UBC Theses and Dissertations

UBC Theses Logo

UBC Theses and Dissertations

Life history variation in Neomysis mercedis holmes (Crustacea, Mysidacea) Johnston, Norman Thomas 1985

Your browser doesn't seem to have a PDF viewer, please download the PDF to view this item.

Item Metadata

Download

Media
831-UBC_1985_A1 J63.pdf [ 9.02MB ]
Metadata
JSON: 831-1.0096613.json
JSON-LD: 831-1.0096613-ld.json
RDF/XML (Pretty): 831-1.0096613-rdf.xml
RDF/JSON: 831-1.0096613-rdf.json
Turtle: 831-1.0096613-turtle.txt
N-Triples: 831-1.0096613-rdf-ntriples.txt
Original Record: 831-1.0096613-source.json
Full Text
831-1.0096613-fulltext.txt
Citation
831-1.0096613.ris

Full Text

LIFE HISTORY VARIATION IN Neomysis  mercedis HOLMES (CRUSTACEA,  MYSIDACEA) by NORMAN THOMAS JOHNSTON B.Sc.(Hon),University of Manitoba,1970 M.Sc.,McMaster U n i v e r s i t y , 1 9 7 2 M . S c . , U n i v e r s i t y of B r i t i s h Columbia,1981 A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY in THE FACULTY OF GRADUATE STUDIES (Department of Zoology) We accept t h i s t h e s i s as conforming r e q u i r e d standard  t o the  THE UNIVERSITY/OF BRITISH COLUMBIA 30 January 1985 @  Norman Thomas Johnston, 1985  In p r e s e n t i n g  t h i s t h e s i s i n p a r t i a l f u l f i l m e n t of  requirements f o r an advanced degree a t the  the  University  o f B r i t i s h Columbia, I agree t h a t the L i b r a r y s h a l l make it  f r e e l y a v a i l a b l e f o r reference  and  study.  I further  agree t h a t p e r m i s s i o n f o r e x t e n s i v e copying o f t h i s t h e s i s f o r s c h o l a r l y purposes may department o r by h i s o r her  be granted by the head o f representatives.  my  It i s  understood t h a t copying or p u b l i c a t i o n o f t h i s t h e s i s f o r f i n a n c i a l gain  s h a l l not be allowed without my  permission.  Department o f The U n i v e r s i t y of B r i t i s h Columbia 1956 Main Mall Vancouver, Canada V6T 1Y3 Date  DE-6  (3/81)  11 i W  KB  written  i i  ABSTRACT This  t h e s i s  parameters mysid  to  and  p a t t e r n s  t e s t  s e v e r a l  P o p u l a t i o n s s p e c i f i c  examines  of  N.  f i t n e s s .  a l l o c a t i o n  was  phenotypic r e l a t e d  v a r i a t i o n  components  N.  mercedis  produced  three  demographic matured  at  reduced  shown  smaller  the  and  breeding summer. to  the  to  food  on  to  p e r i o d The  mysids but  were  m o r t a l i t y  abundance  of  a v a i l a b i l i t y ,  as  per  e f f e c t s  r a t e s  which  d e l t a  had  i n  i n  t h e i r  g e n e r a t i o n s l a r g e r  r a t i o s body  eggs,  than  s i z e  the were  t e m p e r a t u r e . r a t e s  were  constant  l a r g e r  salmon of  m o r t a l i t y d u r i n g  animals  f r y  were and  s e v e r a l  i n  the  throughout  measures  animals  l a r g e  g r e a t e s t  values  w i t h  neonates  those  R i v e r  d i f f e r e d  sex  instantaneous  predatory  dependent s i z e -  Summer  changes  d i r e c t l y  of  of  a l t e r e d  F r a s e r  even  on  manner  s i z e .  more  r e l a t i v e l y  on  age-  r e p r o d u c t i v e  which  embryos,  of  a  temperature  the  of  maximization  fewer  b i r t h  higher  w h i l e  of  i n  water t h e o r y .  regimes  which  c l u t c h  year  Seasonal  than  by  t r a i t s .  and  v a r i e d  the  m a t u r i t y  marshes  S i z e - s p e c i f i c  small  at  c a r r i e d  low  on  through  such  c a p i t a  Fecundity  a v a i l a b i l i t y . higher  the per  d e c l i n e d  summer.  s i z e  r a t e s ,  from  Instantaneous s p r i n g  l a r g e l y  g e n e r a t i o n .  r e s u l t  based  h i s t o r y  s i z e ,  f e r t i l i t y  to  r e p r o d u c t i o n  t i d a l  l i f e  h i s t o r y  to  f i t n e s s  the  l i f e  demographic  b r a c k i s h  energy  mechanism  the  a  d i f f e r e n t  g e n e r a t i o n s  and  o v e r w i n t e r i n g  i n  of  i n  was  i n  to  The  v a r i e d  of  between  s u b j e c t  p r e d i c t i o n s  i n d i v i d u a l  a l l o c a t i o n  p r e d i c t i o n s  a l l o c a t e d  w i t h  r e l a t i o n s h i p  energy  mercedi s  m o r t a l i t y  c o n s i s t e n t  of  the  of  food  r a t e s the  d u r i n g  were  s p r i n g  the  l a t e  d i r e c t l y  r e l a t e d  i n v e r s e l y  r e l a t e d  l a r g e r  s i z e  c l a s s e s  v a r i e d  i n v e r s e l y  s t r o n g l y c l a s s e s , was  s e l e c t i v e t h e  a  phenotypic The S2  l i f e t i m e  summer  t h e i r  than  about  of  of  690,  t h e W  o f  o f  t h e summer  females  (12-13%  be  s i z e  i n c r e a s i n g  s i z e  temperature,  which  temperature  dependent  s e l e c t e d .  females and  females of  g e n e r a l l y  t h e mature  w i t h  c o u l d  195,  a l l o c a t i o n  e f f o r t  r a t e  which  budgets  was  F o r  e n v i r o n m e n t a l  s i z e  o v e r w i n t e r i n g  p a t t e r n s  that  with  i n a d u l t  p r e d a t i o n  m y s i d s .  through  energy  were  and  r e p r o d u c t i v e  l a r g e  c o r r e l a t e d  v a r i a t i o n  F i s h  i n m o r t a l i t y  mechanism  g e n e r a t i o n s  The  food.  f o r  increment  p o s i t i v e l y  provided  w i t h  from  175  t h e W,  J  d i f f e r e d  r e s p e c t i v e l y .  s i g n i f i c a n t l y  a s s i m i l a t e d females  was  versus  8.5%  S 1 , and  energy.  about of  i n The  50%  g r e a t e r  t h e  energy  budget). My  r e s u l t s  p r e d i c t i o n s i n c r e a s e d in  N.  l i f e  when  mercedis  f e c u n d i t y decreased phase  o f  o f  imposed  t h e  u p r i v e r  a  found  c h a r a c t e r i s t i c s .  r a t e s  cost  w i t h  between  p o p u l a t i o n  of  t h e  e f f o r t  were  Reproduction  i n terms  i n c r e a s e d  However,  s e v e r a l  Reproductive h i g h . o f  s u r v i v o r s h i p . e f f o r t  p o p u l a t i o n .  freshwater  t h e o r y .  r e a l  decreased  was  agreement  m o r t a l i t y  r e p r o d u c t i v e  d i f f e r e n t i a t i o n an  i n  h i s t o r y  a d u l t  and and  were  no  reduced Age  a t  d u r i n g evidence  f u t u r e m a t u r i t y  t h e  growth  of  g e n e t i c  t h e e s t u a r i n e  p o p u l a t i o n  which  i n  d i f f e r e d  was  and  r e p r o d u c t i v e  iv  TABLE  OF  CONTENTS  ABSTRACT  i  LIST  OF  TABLES  ..  LIST  OF  FIGURES  v i i i x  ACKNOWLEDGEMENTS GENERAL  i  .  xv  INTRODUCTION  1  I n t r o d u c t i o n  1  The  Problem  2  The  Animal  The  Aims  CHAPTER  1.  HOLMES  and  and THE  IN  i t s Environment  O r g a n i z a t i o n POPULATION  THE  TIDAL  of  Study  MARSHES  OF  THE  OF  9  Neomysis  FRASER  6  RIVER  mercedis ESTUARY  11 11  and S i t e  C o l l e c t i o n A n a l y s i s  t h e T h e s i s  DYNAMICS  I n t r o d u c t i o n M a t e r i a l s  ....  of  Demographic  Methods  12  D e s c r i p t i o n  12  Methods  14  F i e l d  Samples  Analyses  R e s u l t s  16 19 25  P h y s i c a l  Parameters  25  Abundance  25  Body  32  Egg  S i z e S i z e  35  F e c u n d i t y Sex  R a t i o  38 and  F e r t i l i t y  43  V  Demography F i s h  .  46  P r e d a t i o n  D i s c u s s i o n Body Egg  57  ..  S i z e S i z e  .... .. V a r i a t i o n  •  65 66  V a r i a t i o n  69  Demography  76  L i f e  82  H i s t o r y  CHAPTER  2.  Neomysis  THE  UTILIZATION  mercedis  IN  THE  OF  FRASER  ASSIMILATED RIVER  ENERGY  BY  ESTUARY  84  I n t r o d u c t i o n Methods  84  and  M o l t i n g  M a t e r i a l s and  86  Growth  86  Energy  Content  88  Oxygen  Uptake  89  R e s u l t s  92  Growth  92  M o l t i n g  97  Energy  Content  103  Oxygen  Uptake  103  Energy  Budgets  108  D i s c u s s i o n  113  P h y s i o l o g i c a l L i f e  H i s t o r y  Energy CHAPTER  3.  POPULATION  Rates  113  Theory  123  Budgets LIFE OF  I n t r o d u c t i o n  HISTORY Neomysis  128 VARIATION m e r c e d i s  IN  HOLMES  A  FRESHWATER 132 132  v i  M a t e r i a l s Study  and S i t e  Methods and  .......133  C o l l e c t i o n  Methods  .........  ...133  E l e c t r o p h o r e s i s R e s u l t s  ..  Body Egg  .134 1 34  S i z e S i z e  C l u t c h  "... and  F e c u n d i t y  136  Weight  138  E l e c t r o p h o r e s i s D i s c u s s i o n GENERAL  136  ...  140  .  141  DISCUSSION  Appendix T i d a l  1:  The  2:  Appendix  3:  of  Neomysis  mercedis  from  The  147  S e l e c t i v i t y  The  A c c u r a c y  E s t i m a t e d  Appendix  4:  P o p u l a t i o n Appendix  O u t m i g r a t i o n  Channels  Appendix  Rates  144  5:  Nicomen  The  w i t h  t h e  E f f e c t s  of  t h e  of  Sled-Towed  S i z e - s p e c i f i c  Lynch of  Net M o r t a l i t y  A l g o r i t h m  Egg  S i z e  152 on  Rates  of  I n c r e a s e The  L i f e  H i s t o r y  157 of  Neomysis  mercedis  Slough  P h y s i c a l  149  at 160  Parameters  .....160  Abundance  160  F e c u n d i t y  164  Appendix R e f e r e n c e s  6:  Enzymes  Surveyed  E l e c t r o p h o r e t i c a l l y  171 172  v i i  LIST  Table  1.  Summary  of  OF  r e l a t i o n s  TABLES  between  s i z e  and  r e p r o d u c t i v e  parameters Table  2.  38  Homogeneous  r e p r o d u c t i v e Table  3.  Table  4.  output  Summary  Neomys is  L i n e a r  Table  Table  of  6.  7.  8.  Average  d i f f e r e n t Table  at  for  9.  the  m o r t a l i t y  44 of  of  f i s h  Neomysis  I s l a n d ,  Neomysis  ( d a y  - 1  )  on 59  t o  the 61  m o r t a l i t y  r a t e s  on  1977-1978 growth  64  r a t e s  and  mercedis  ; .. .  at  four  temperatures  99  r e g r e s s i o n s  of  s i z e  molt  r a t e  c l a s s e s  of  versus Neomysi s  mercedi s Table  10.  100  Slopes  r e g r e s s i o n s Table  11.  uptake)  96  f o r  mercedis  d i f f e r e n t  46  of  1977-1978  between  p e r i o d s  Neomysis  r a t e s  mercedis  p r e d a t i o n ,  r e l a t i o n s h i p  dependence  abundance  i n s t a n t a n e o u s  from  f o r  f o r  p r e d a t o r  Woodward  F u n c t i o n a l  temperature  models  i n t e r m o l t  s i z e  of  . .  r e p r o d u c t i v e c h a r a c t e r i s t i c s  c o n t r i b u t i o n  l i n e a r  temperature T a b l e  and  mercedis  The  c o n d i t i o n  measures  .  S i z e - s p e c i f i c  Neomysis Table  the  i n s t a n t a n e o u s  f i s h e s  s i z e - a d j u s t e d  female  r e g r e s s i o n  Average  d i e t s  of  .  a v a i l a b i l i t y  5.  and  of  mercedi s  s i z e - s p e c i f i c food  groupings  of  (and  95%  log(oxygen  C o e f f i c i e n t s =  a  +  c o n f i d e n c e  b«log(W)  of +  uptake) the  l i m i t s )  f o r  a g a i n s t  l o g ( w e i g h t )  r e g r e s s i o n  o l o g ( T )  +  d-log(S)  f u n c t i o n a l  model  l o g ( 0  ..106  2  107  v i i i  Table  12.  L i f e t i m e  metabolism,  a l l o c a t i o n  and  of  energy  r e p r o d u c t i o n  to  f o r  growth,  m o l t i n g ,  female  Neomysi s  mercedi s Table  13.  .......110  L i f e t i m e  metabolism, Table  14.  and  15.  r a t e s  and  16.  Energy  Table  17.  L i f e t i m e  18.  and  mercedis  of  energy  to  i n  double  brooding  weight  growth,  dependence  of  111  m o l t s ,  females  113  m e t a b o l i c 119  1  d e n s i t i e s energy  (J*mg~ )  f o r  a l l o c a t i o n  Comparison output  e s t u a r i n e 19.  The  Nicomen Table  of  and  mysids  (%)  i n  122  s e v e r a l  and  s i z e - a d j u s t e d  female  p o p u l a t i o n s  f r e q u e n c i e s  Slough  A1.  s i z e  of  of PGI  Woodward  M o r t a l i t y  r a t e s  s p e c i e s  M o r t a l i t y  r a t e s  s i z e  frequency A4.  Neomysis  A  r a t e s  u s i n g  mercedis  at  of  ....138  enzyme  f o r  u s i n g  a  the  f o r the  e s t i m a t e d  d i s t r i b u t i o n  summary  f r e s h w a t e r  v a r i a n t s  at 140  u s i n g  e s t i m a t e d  d i s t r i b u t i o n  M o r t a l i t y  MDH  e s t i m a t e d  A2.  A3.  i n  of  I s l a n d  d i s t r i b u t i o n  Table  measures  mercedis  and  frequency  frequency  c o n d i t i o n  N.  -  s i z e  Table  Neomysis  m o l t i n g ,  129  r e p r o d u c t i v e  Table  male  growth,  mysids  Table  Table  the  t o  mysids  Table  of  a l l o c a t i o n  f o r  energy f o r  r e p r o d u c t i o n  Exponents i n  of  r e p r o d u c t i o n  L i f e t i m e  metabolism, Table  a l l o c a t i o n  the  Slough  Lynch  Lynch f o r  ..155  i n i t i a l  a l g o r i t h m  r e l a t i o n s  154  i n i t i a l  a l g o r i t h m  P o i s s o n  Lynch  i n i t i a l  a l g o r i t h m  Gaussian  size-dependent  Nicomen  uniform  ..156 f o r 167  ix  LIST  F i g u r e  1.  Map  of  OF  t h e F r a s e r  River  s i t e F i g u r e 1977  t o  1977  Woodward 3b.  4.  5.  a d u l t  water  s a l i n i t y  seasonal  a t  Woodward  a t  I s l a n d  Woodward  I s l a n d  of  October  1977  between  biomass  I s l a n d  abundance  (± 1  from  1977  seasonal  mercedi s  SE)  a t  I s l a n d  from  and  S e a s o n a l female  March  March  1979  m e r c e d i s  a t  ....  28 of  I s l a n d ,  of  female 1977  j u v e n i l e s ,  a t  Woodward  t o  and  male  1979  29  immatures,and I s l a n d  between 31  i n t h e mean  m e r c e d i s  a t  s i z e  (±  Woodward  1  SE)  I s l a n d ,  of 1977  F i g u r e s i z e  33  6b.  a d u l t  The  male  seasonal Neomysis  6 c . The of  p a t t e r n  of  mean  m e r c e d i s  a t  Woodward  seasonal  a d u l t  female  p a t t e r n  of  Neomysis  t h e  (± 1  10  SE)  s i z e  of  I s l a n d percent  m e r c e d i s  a t  33 q u a n t i l e Woodward  I s l a n d F i g u r e  28  a t  1979  changes  Neomysis  and  mercedi s  1979  F i g u r e  26  from  1979  Woodward  mercedi s  Neomysi s  Neomysis  abundance  Neomys is 1977  of  t o  p r o p o r t i o n s  6 a .  a d u l t  temperature  R e l a t i v e  October  13  26  The  Neomysi s  -  study  .  The  The  Woodward  F i g u r e  t h e  1979  3 a .  F i g u r e  water  Bottom  t o  F i g u r e  F i g u r e  showing  1979  2b.  F i g u r e  d e l t a  . 2 a . Bottom  F i g u r e  FIGURES  7 a . The  33 s i z e  a t  m a t u r i t y  (± 1  SE)  of  reared  male  and  X  female F i g u r e s i z e  Neomysis  mercedis  7b.  The  e f f e c t s  a t  m a t u r i t y  of  of  a t  d i f f e r e n t  p r i o r  temperature  female  N.  I s l a n d F i g u r e for F i g u r e  9 a . The  frequency mercedis  h i s t o r y  mercedis  a t  on  9b.  The  10a. The  Woodward between  mean  I s l a n d , brood  Woodward  eggs  r e l a t i o n s h i p  between  brood  " l a r g e "  eggs  p r o d u c i n g  f o r  between  Neomysis  egg  and  d u r i n g s i z e  a t  ....  and  ....  1978  ....  weight  Woodward  10b. The  11a.  The  embryos  embryos, F i g u r e  and  I s l a n d ,  F i g u r e  on  12.  The  :  females  13. The  14.  mercedis  a t  Woodward  dependence  of  t h e  female  The  embryos  female  sperm  s i z e  weight  male  I s l a n d  number  f o r females  and  of  41  stage  c a r r y i n g  I I  and  " s m a l l " 42  V  males  between  1978  11b.  stage  F i g u r e  r e l a t i o n s h i p  f o r Neomysis  F i g u r e  F i g u r e  39  41  s i z e  I I I  39  female  1978 F i g u r e  36  female  1978  d u r i n g  t h e c l u t c h  mercedis  weights  1978-1980  s i z e  " s m a l l "  r e l a t i o n s h i p  s i z e  of  p r o d u c i n g  f o r females  female  a t  t h e  - 3 4  d i s t r i b u t i o n s  r e l a t i o n s h i p  f o r females  s i z e F i g u r e  The  Neomysis  F i g u r e  . . . . . 34  .  8.  s i z e  temperatures  dependence on  s e a s o n a l a t  average  number  m e r c e d i s ,  1977  -  of 1979  number  that  of  IV  and  1977  t h e t o  r a t i o  of  1977  t h e p r o p o r t i o n  45 of  a d u l t  a r e g r a v i d  p a t t e r n eggs  stage  42  of  I s l a n d ,  p a t t e r n  of  1978  p a t t e r n  mercedis  seasonal  t h e  s i z e ,  Woodward  seasonal  Neomysis The  female  of  p e r  a t  45  Woodward  a d u l t  female  I s l a n d  of  Neomysi s 45  xi  F i g u r e  15.  Neomysis F i g u r e  Per  mercedis  16.  r a t e s  of  the  of  b i r t h  I s l a n d ,  p e r  c a p i t a  mercedi s  a t  r a t e s  f o r  1978  47  i n s t a n t a n e o u s  Woodward  b i r t h  I s l a n d  on  d e n s i t y  17a. Food  17b.  i n s t a n t a n e o u s Woodward  Neomysis  mercedis. a t F i g u r e  a t  Dependence  p o p u l a t i o n F i g u r e  c a p i t a  47  r e s o u r c e  Woodward  number  index  f o r  Neomysis  I s l a n d  C o r r e l a t i o n  average  supply:demand  49  between  of  eggs  egg  p e r  p r o d u c t i o n  a d u l t  (measured  female)  and  as food  a v a i l a b i l i t y F i g u r e (and  18.  Seasonal  95%  d i s t r i b u t i o n  Woodward F i g u r e  I s l a n d ,  1)  19b.  ( c l a s s F i g u r e  and  2 0 a .  from  Woodward 20b.  2 1 .  mercedis  Neomysis  r a t e s  mercedis  a t  4)  5)  t o  c l a s s  neonates 56  r a t e s  between  neonates  a n i m a l s  v a r i a t i o n p e r  between  a n i m a l s  i n m o r t a l i t y ( c l a s s  r a t e s  u n i t 5  i n  56  t h e  increment  time  with  f o r  Neomysis  i n t h e  i n c r e a s i n g  s i z e  mercedis  a t  I s l a n d  58  Seasonal  c l a s s  Woodward  of  i n m o r t a l i t y  death  4  i n s t a n t a n e o u s death  50  ( c l a s s  a d u l t  of  p r o b a b i l i t y  F i g u r e  l i m i t s )  Seasonal  c l a s s  (from  a d u l t  1) and  i n  1977-1979  D i f f e r e n c e  p r o b a b i l i t y  F i g u r e  v a r i a t i o n  19a. D i f f e r e n c e  ( c l a s s F i g u r e  49  of 5  v a r i a t i o n  death  t o  p e r  c l a s s  i n  u n i t 6)  t h e time  f o r  increment w i t h  i n  i n c r e a s i n g  Neomysis  t h e s i z e  mercedis  a t  I s l a n d Seasonal consumed  58 changes by  i n t h e p r o p o r t i o n  p a r t i c u l a r  f i s h  of  s p e c i e s ,  Neomysis 1977  x i i  1978  60  F i g u r e  22.  mercedis  Seasonal consumed  changes by  f i s h  i n t h e mean  a t  s i z e  Woodward  of  Neomysis  I s l a n d ,  1977  1978  60  F i g u r e  23.  R e p r e s e n t a t i v e  mercedis: and  sets  of  s i b l i n g s  curves a t  (a)  f o r  Neomysis  10°C, (b)  15°C,  ( c ) 20°C  F i g u r e  24.  mercedis F i g u r e  three  growth  The on  F i g u r e  dependence  frequency  mercedis  26a.  of  t h e growth  r a t e s  of  The  95  of  h e l d  c l u t c h e s  under  dependence  produced  l a b o r a t o r y o f  t h e  by  mature  c o n d i t i o n s  molt  98  frequency  on  temperature F i g u r e  101  26b. The  frequency F i g u r e  -  2 6 c .  dependence temperature  The  o f  t h e  slopes  r e l a t i o n s  dependence  o f  on  t h e egg  o f  body  t h e  molt  s i z e  101  development  r a t e  on  temperature F i g u r e  27b.  female  Neomysis  and 28.  mercedis F i g u r e  mercedis  The  2 7 c . The  eggs, F i g u r e  dependence  Neomysis  F i g u r e  F i g u r e  101  2 7 a . The  male  The a t  of on  t h e animal  mercedis  animal  of  on  content Neomysis  6.5,  mean  10,  s i z e  a t Nicomen  (±  Slough,  m o l t s  from 102  t h e weights  1  o f  m o l t s  from  s i z e SE)  102 of  body  t i s s u e ,  mercedis of  15, and (± 1  o f  s i z e  o f  dependence  5,  weights  dependence  energy  m o l t s  2 9 a . The  mercedis  93  Neomysis  temperature  25. The  Neomysis  .  SE)  oxygen 20°C o f  102 uptake on  a d u l t  1977-1979  body  by  Neomysis  weight  female  ....104  Neomysis 135  F i g u r e  29b. The  mercedis F i g u r e  F i g u r e  Nicomen  30b. The  F i g u r e  3 1 a . The  s i z e F i g u r e  r e l a t i o n s h i p  Neomysis F i g u r e of  A2.  The  d i f f e r e n t  F i g u r e 1m  e m i g r a t i o n  A3. depth  F i g u r e and  A4.  on  s i z e s  Bottom  water  a t Nicomen  mean  egg  weights  of  mean  egg  weights 137  and  female  body 139  between S l o u g h ,  (numbers t i d e s  a t  t h e s l e d - t o w e d  Slough  c l u t c h  from  s i t e s  a t  1977  0.5  night  of  and  h)  of  mid-day  Neomysis  151  midchannel -  and  a t  1979 a t  Nicomen  161 t h e  nearshore  Slough  1977  197 9 F i g u r e  161 A5.  The  d e n s i t i e s  embryos,  (b)  Neomysis  mercedis  F i g u r e a d u l t  148  mercedis  n e t  (#'irr ) a t  and 139  per  2  d e n s i t i e s  weight  1978  c a t c h a b i l i t y  sampling  Nicomen  ....137  t e m p e r a t u r e s  P o p u l a t i o n  m i d c h a n n e l  a t  s i z e  1978  f a l l i n g  by  of  f e c u n d i t y  r a t e  r e l a t i v e  t h e  1978  a t Nicomen  mercedis  on  1978  between  31b.  A 1 . The  135  mercedis  d i s t r i b u t i o n  S l o u g h ,  s i z e  Neomysis  ............135  i n summer  r e l a t i o n  body  female  temperatures  Neomysis  a t Nicomen  female F i g u r e  ambient  d i s t r i b u t i o n  frequency  The  a d u l t  1977-1979  i n s p r i n g  s l o u g h  o f  I s l a n d  frequency  Slough  Nicomen  o f  female  Woodward  30a. The  F i g u r e at  and  of  s i z e  S l o u g h ,  e f f e c t s  m a t u r i t y  Slough  d e c i l e  a t Nicomen  2 9 c . The  at  at  f i r s t  A6.  j u v e n i l e ,  Seasonal  female  a t  (number ( c )  Nicomen  v a r i a t i o n  Neomysis  p e r n r  immature, S l o u g h  from  2  ) of and  (d)  1977  t o  i n t h e p r o p o r t i o n  mercedis  a t  Nicomen  female  (a) a d u l t  1979  o f  S l o u g h ,  ..163  g r a v i d 1977  xiv  to  1979  F i g u r e per . 1977 F i g u r e  A7.  Seasonal  a d u l t t o A8.  Neomysis F i g u r e  A9.  per  m )  1979  ...165  2  v a r i a t i o n  female  i n t h e average  Neomys is  mercedi s  a t  number Nicomen  of  eggs  Slough  1979  1 65  Seasonal mercedis Seasonal of  v a r i a t i o n a t  Nicomen  v a r i a t i o n  Neomysis  i n t h e malerfemale Slough  1977  i n t h e biomass  m e r c e d i s  a t  Nicomen  t o  r a t i o  of  1979  (mg  d r y  Slough  168 weight 1977  t o 168  XV  Acknowledgements I  am  g r a t e f u l  encouragement N e i l l , of  and  t o my  d u r i n g  C o l i n  i d e n t i f y i n g  t h e  e l e c t r o p h o r e s i s . Levy,  and Tom  Lewis, d r a f t 3454  Greg  of  I  Steer  C o l i n  t o T.G.  am  I  and  of  E r i c  N e i l l ,  N o r t h c o t e .  work  N o r t h c o t e ,  work.  D r .  g r a t e f u l me  C.  was  t o  i n t h e  C a r e f o o t ,  h e l p f u l  John  f o r  D a v i s ,  t h e f a c i l i t i e s  P a r k i n s o n  Tom  p r o v i d e d  T h i s  t h i s  thank  f o r a s s i s t i n g B i l l  Tom  p r o v i d e d  e s p e c i a l l y  Levings  t h e t h e s i s .  k i n d l y  work.  mysid  N o r t h c o t e ,  and  t h e course  L e v i n g s  t h e experimental  s u p e r v i s o r ,  f o r a r r a n g i n g Y e s a k i ,  f o r t h e Dave  f i e l d w o r k . C h a r l e y  comments  supported  B i l l  f o r much  Holmquist  I t s u o  h i s  by  on  NSERC  Krebs, an  A l  e a r l i e r  grant  67-  1  GENERAL  INTRODUCTION  I n t r o d u c t i o n  This  work  p o p u l a t i o n s m o r t a l i t y energy  r a t e s  budget  m o r t a l i t y a r i s e s l i f e  i n  h i s t o r y  q u e s t i o n  what  p a t t e r n s and  a d u l t  theory  m o r t a l i t y  of  r i s e  r a t e s  t o a  or  How  what  of  energy  d i v e r g e  do a r e  of  a t t e n t i o n of  that  t h e  a l l o c a t i o n i n l i f e  p r e d i c t i o n s  one  which of  on  r a t e s  h i s t o r y  has  t h e  been  which  a l l o c a t i o n such  of  above  f a c t o r s  q u e s t i o n s  p r o x i m a t e by  t o t a l  q u e s t i o n  d e t e r m i n e  m o r t a l i t y  t h e i r  i n t h i s  energy  a n c i l l a r y  j u v e n i l e  j u v e n i l e  q u a l i t a t i v e and  "Do  i n which  C o n s i d e r a t i o n  p a t t e r n s of  exceed  I n t e r e s t  1983a)  f a c t o r s  (2)  g e n e t i c a l l y ?  1976;  d a t e .  q u e s t i o n  r a t e s  p o p u l a t i o n s  t h e major  number  m o r t a l i t y ?  which  than  m o r t a l i t y ? " . of  t h e  p r o p o r t i o n  focusses  p r o x i m a t e  p a t t e r n s  p o p u l a t i o n s d i v e r g e  t o  w i t h  m o r t a l i t y  g r e a t e r  (Stearns  t e s t e d  s p a t i a l l y ?  i n f l u e n c e  a d u l t  i t i s one  t h e  a  r e p r o d u c t i o n  n e c e s s a r i l y  g i v e s a r e  which  exceeds  i n a d e q u a t e l y  thus  p r i n c i p a l l y  a l l o c a t e  t o  because  i n f l u e n c e  d e a l s  and  a s  (1)  a g e - s p e c i f i c  vary  t e m p o r a l l y  f a c t o r s  t h e organism?  which (3)  c h a r a c t e r i s t i c s  do  a l s o  2  The  L i f e  h i s t o r y  t r a i t s : (2)  (1)  the  the  number  imposed  by  s e l e c t i o n  i s  theory  d e a l s  amount  and  s i z e  of  and the  Problem  g e n e t i c s  expected  to  p r i m a r i l y  t i m i n g young. and  shape  Attempts  to  account  p a t t e r n  generated  an  enormous  in  G i e s e l  (1976),  Stearns  (1977,  ideas  u n d e r l y i n g  a d a p t i o n i s t  1980)  and  (1979).  paradigm  i m p l i c i t  Theories  1975)  take  to  her  g e n e r a t i o n s  f o r  l i f e d e a l  as the  ( F i s h e r  the the  the  organism,  to  i n  maximize  r e p r o d u c t i v e  which  i s  and  Calow  the  reviewed  data  viewpoint c r i t i c i s m s  (1977). and  i s  defended  the  i m p l i c i t l y  of  the  Gould  and  a d a p t i o n i s t  t h e o r y . the  o p t i m a l Taylor  s t a r t i n g  c o n t r i b u t i o n  newborn  c o n s t r a i n t s  a s s e s s e d  1974;  t h e i r  W i t h i n  1980),  has  w i t h  and  l i t e r a t u r e  to  h i s t o r y  e f f o r t ,  v a r i a t i o n  1977,  (1983)  ( S c h a f f e r  v a l u e ,  r e l a t i v e  f u t u r e  i n  e f f o r t  r e p r o d u c t i v e makes  Mayr  r e p r o d u c t i v e  f a c t o r s  the  s u s c e p t i b l e  of  above  (1976,  theory;  sets  of  c r i t i c a l l y  the  which  r e p r o d u c t i v e Parker  has  thus  Lewontin  and  Stearns  two  p h y s i o l o g y  the  " f i t n e s s " . have  of  w i t h  a l l o c a t i o n  et  a l .  p o i n t  the  that  c o n t e m p o r a r i e s  a to  1974;  of Pianka  concept  female the  of  age  a n c e s t r y  of x of  1930):  oo  [1]  V(x)  =  [ e x p ( r - x ) / l ( x ) ]  Z  [ e x p ( - r - y ) • 1 ( y ) • b ( y ) ]  y=x  where  r  i s  s t a b l e  age  i n t r i n s i c  d i s t r i b u t i o n  s u r v i v o r s h i p f i t n e s s  the  u s i n g  l ( x ) r  as  and a  r a t e  d e f i n e d f e c u n d i t y  f i t n e s s  by  of  n a t u r a l  the b ( x ) .  measure  i s  i n c r e a s e  a g e - s p e c i f i c  schedules  M a x i m i z i n g e q u i v a l e n t  under  to  the of  i n d i v i d u a l m a x i m i z i n g  3  the  r e p r o d u c t i v e  1981).  But  1966;  the  Pianka  value  and  Parker  r e p r o d u c t i o n  [2]  V(x)  c u r r e n t  terms 1979;  of  =  l e v e l  of  1980)  r e p r o d u c t i v e s p e c i f i c  and  s u r v i v a l which  the  can  i n t o  (Schaffer  be  1974;  p a r t i t i o n e d  components  e x p e c t a t i o n  r e p r o d u c t i o n , or  are  e f f o r t .  from  1975)  age  of  ( W i l l i a m s  which  f u t u r e  Ypdzis  represent  r e p r o d u c t i o n :  +[l(x+l)/l(x)].V(x+l)  however,  decreased  assumed  Thus  r e p r o d u c t i v e  r e s u l t i n g  value  the  b(x)  decreased  B e l l  every  r e p r o d u c t i v e  c u r r e n t  The  at  the  f u t u r e  of  c o s t s  f e c u n d i t y  increase  o p t i m a l  e f f o r t  i n t e r a c t i o n  to  imposes  with  i s  determined  the  f e c u n d i t y  by and  (Calow  the  a l l o c a t i o n  i n  c u r r e n t of  age-  t r a d e - o f f s s u r v i v o r s h i p  schedules. Reproductive t o t a l  energy  ( H i r s h f i e l d  or  of  budget and  d e f i n i t i o n r a t i o  i s  c l u t c h  v a r i o u s  e f f o r t  favoured weight  the  i n t a k e  t o  from  T i n k l e  1975).  t h i s  manner,  both  under  which  over to  (1)  measures weight  cost  the  c u r r e n t  to  as  ( T i n k l e 1979) and  of  l e v e l s  and  r e p r o d u c t i v e  i s a l t e r e d  i n c r e a s e s  and  f i t n e s s  (2)  i t s  1983).  This  w e i g h t ,  Hadley  the  1975),  because  i t  appears  because  i t  l a r g e l y  animal of  of  r e p r o d u c t i o n  c l u t c h  s i z e  e f f o r t  the  become  and  of  ( H i r s h f i e l d  e f f o r t  p h y s i o l o g i c a l mechanisms  a l l o c a t i o n  r e - a l l o c a t i o n  of  p r o p o r t i o n  a l .  such  e f f o r t  e f f e c t s  comparisons With  et  (Calow t o  the  a l l o c a t e s  Tuomi  i n d i c e s  l i n k  as  organism  body  confounding  and  resource  the  1975;  p h y s i o l o g i c a l  e l i m i n a t e s  which  that  T i n k l e  s t r a i g h t f o r w a r d l y  resource  i s measured  by  d e f i n e d  i n  means  of  circumstances q u e s t i o n s  of  4  i n t e r e s t  ( F i s h e r  Numerous e v o l u t i o n  of  1930). authors  " o p t i m a l "  e x h a u s t i v e l y  reviewed  the  and  d i r e c t i o n  s p e c i f i e d p.275)  changes have  connecting  (1)  r e s u l t e d  r e p r o d u c t i v e  " h i g h ,  v a r i a b l e ,  decreased  "where  j u v e n i l e  exceeds  s e v e r a l  times"  (3)  or  Attempts  i n p h e n o t y p i c  r e c u r r i n g and  e f f o r t  u n p r e d i c t a b l e e f f o r t  work  t o  of  i s  " p r e d i c t  t r a i t s  when  (Stearns  s e t  t h e  1980,  p r e d i c t i o n s  m o r t a l i t y :  u n p r e d i c t a b l e  a d u l t  a d u l t  e a r l y  j u v e n i l e and  m o r t a l i t y  i n l i f e "  m o r t a l i t y  longer  r e p r o d u c t i v e d e c r e a s e d  a d u l t  r a t e s  whereas  w i l l  l i f e "  favour (Stearns  f r e e  of  p r e d i c t i o n s t e s t  These  of  only  j u v e n i l e  once t h e  i n  i n  c u r r e n t  e f f o r t ,  r e p r o d u c t i v e  through  f e c u n d i t y  t h e  should  f i r s t  (Pianka  two  of  t h e Where  reproduce  of  h i s t o r y a r e  wide  and  w i l l  reduce  s u r v i v o r s h i p Parker  t h e above  should  be  e f f o r t  decreased  assumptions  p r e d i c t i o n s  i t sl i f e t i m e .  organism  r e s t r i c t i v e  l i f e  m o r t a l i t y ,  1976, p . 3 ) ,  f u t u r e  of  exceeds  m o r t a l i t y ,  (Stearns  i n c r e a s e s  v i r t u a l l y  m o r t a l i t y  reproduce  d e r i v a t i o n  strong  a  of  t h e i r  environment"  r e p r o d u c t i v e  a d u l t  should  the  (1976).  i n t h e  q u e s t i o n  s t r a t e g i e s ;  changes  p a t t e r n  r e p r o d u c t i v e  organism  The  or  of  t h e  p.60),  (2)  through  h i s t o r y  i n  v a r i a b l e ,  "high,  addressed  i n Stearns  a r e made  f o r i n c r e a s e d  f u t u r e  l i f e  magnitude  s e l e c t  1983a,  have  (Horn  or  1975).  p r e d i c t i o n s 1978).  a p p l i c a t i o n and  i s  Thus,  comprise  a  t h e o r y . g e n e r a l l y  t e s t e d  by  comparing  t h e  5  p r e d i c t e d i s ,  and  by  c o r r e l a t i n g  c o n d i t i o n s in  observed  l i f e  assumed  to  genotypes  1976;  r e s u l t  l i f e  s t r a t e g i c  the  1983);  G i e s e l  and  as  i t  h i s t o r y  no  p.58)  phenotypic  p l a s t i c i t y  p a t t e r n s  components  of  The  important  phenotypic  1979);  norm  phenotypic  c o n t r o l l e d  of  p l a s t i c i t y  (Gupta  and  p l a s t i c i t y  (Kaplan  Cooper  phenotypic h i s t o r y  i n  p l a s t i c i t y  c o u l d  1982).  I t  Thus be  a  source  been  argued w i l l  genotypic  of  (Futuyma  g e n e t i c a l l y  t r a i t s  e i t h e r  that  s t r a t e g y " .  i s  has  be  r e p r o d u c t i v e  evolve  t r a i t s  r e p r o d u c t i v e  1984).  i n  the  w i l l  suggested  i t s e l f  some  wholly  to  r e p r o d u c t i v e  may  of  that evolve  change  v a r i a t i o n  i n  or l i f e  t r a i t s .  The  l e v e l  e n v i r o n m e n t a l of  i n  Lewontin  d e v e l o p m e n t a l and  r e a c t i o n  i s  s t r a t e g y  "environment-dependent are  above  has  been  s t r a t e g y .  r e f e r e n c e  a p p r o p r i a t e  (1976,  o f t e n  s e l e c t i o n ,  formulated  makes  d i f f e r e n c e s  have  under  l i f e  that  e n v i r o n m e n t a l  Phenotypic  f i x a t i o n ,  the  p o p u l a t i o n s ,  p o p u l a t i o n s  theory  which  implemented.  p a t t e r n s  a p p r o p r i a t e  h i s t o r y  by  the  d i f f e r e n t  1983).  between  from  (Caswell  mechanisms  C a s w e l l  t r a i t s  y i e l d i n g  However,  i n  r e p r o d u c t i v e  (Stearns  h i s t o r y  phenotypes  at  which  h e t e r o g e n e i t y  e n v i r o n m e n t a l  change,  h e t e r o g e n e i t y  as  e n v i r o n m e n t s .  Depending  a d a p t a t i o n  may  p h y s i o l o g i c a l i r r e v e r s i b l e  a d a p t a t i o n  a  t h a t  mean  occur  on as  changes, w i t h i n  occurs  the  as  may  to  depend  i s , on  e n v i r o n m e n t a l  " g r a i n "  of  an  or  temporal  the  the  or  r e v e r s i b l e  developmental l i f e t i m e  on  whether  environment  " e a s i l y  s p a t i a l  frequency  organism as  a l t e r n a t e  (Levins  1968),  b e h a v i o r a l  changes i n d i v i d u a l ,  sees  which or  and are  g e n e t i c  6  a d a p t a t i o n p.37).  r e v e r s i b l e In  p l a s t i c i t y p r o v i d e d  r a p i d l y  i s  developmental An  (Mark to  and  d i r e c t l y  a f f e c t  h i s t o r y the the  the  of  extremely  in  n o r t h  mysids  of  the  p r e d i c t i o n s i n and  s u r v i v a l  by  mysid  l i f e  Neomysis  and  i t s  i n  temperate genus  which  and  Neomysis  that on  the  of  a  l i f e  of  a d u l t s  as  t h e o r y .  p r e d a t i o n ,  food,  which  young  c o n t r a s t s  t h e o r y .  mercedis  environments  h i s t o r y  and  the  r e l a t i v e l y  I  Holmes  may  or  the  i n  l i f e  have 1897  used  t o  t e s t  above.  a r e  Environment  p r e d o m i n a n t l y  w i d e l y  marine  the  zone  of  q u a l i t y  s h r i m p - l i k e ,  nearshore  e s t u a r i e s  heterogeneous  depended  such  h i s t o r y  The  s m a l l ,  of  generate  4)  Animal  ( C a s w e l l  e x p e c t a t i o n  f a c t o r s  of  s h o u l d  c r u s t a c e a n s  water  the  the  the  i n  s e a s o n a l l y - v a r i a b l e  (p.  abundant  e v o l u t i o n  1976) between  environment  p o p u l a t i o n s  summarized  are  B r a c k i s h  i n  q u a n t i t y  water  p r e d i c t i o n s  p e r a c a r i d a n  s e p a r a t e  p r e d i c t e d  b r a c k i s h  of  ( G i e s e l  environment.  v a r i a t i o n  the  f u t u r e  1983,  p h e n o t y p i c  c o r r e l a t i o n  h e t e r o g e n e i t y  the  l i v i n g  young,  t r a i t s  Mysids  of  t e s t i n g  seasonal  weather,  p r o d u c t i o n  study  s t r o n g  c o n f i r m e d  between  i n  polymorphism  the  1982)  organism  u s e f u l  P r e d i c t a b l e  and  ( C a s w e l l  environments,  s u f f i c i e n t l y  p r e d i c t a b i l i t y  s h o r t - l i v e d  g e n e r a t i o n s "  g e n e t i c  e n v i r o n m e n t a l  Comparisons  be  a  e x p e r i m e n t a l  a d a p t a t i o n  may  over  p l a s t i c i t y  environments  temporal  i s  over  f l u c t u a t i n g  favoured  there  1983).  only  waters  lower  reaches  u s u a l l y which  d i s t r i b u t e d  have a  and  (Mauchline of  dense  s i n g l e  marine, o f t e n 1980).  c o a s t a l  r i v e r s  p o p u l a t i o n s  s p e c i e s  of  dominates  7  over  a  wide  T a t t e r s a l l America coast  area:  1951);  (Wigley  of  N o r t h  n o r t h  P a c i f i c  1973);  and  A s i a  ( I i  Kinne  and  America  u s e , and  l i f e  h i s t o r i e s  1982;  Toda  Murtaugh  e t  1983).  s e a s o n a l i t y  i n  g e n e r a t i o n s  p e r  generat  mercedis of  P a c i f i c and  abundance year  w i t h  P a c i f i c t o  W i l l i a m s  and  l i f e  summer  n o t i c e a b l e  west  a l o n g  t h e  Holmquist  s i z e  of  e c o l o g i c a l f e e d i n g ,  T a t e r s a l l 1969;  1951;  M a u c h l i n e e t  a l .  1979; S i e g f r i e d  Bremer  h i s t o r y  a  t h e  1972; W i l l i a m s  Corey  1980;  N o r t h  morphology,  1964; Heubach  and  of  c o a s t  be  and  1983, 1984; Knutson  w i t h  i s abundant  N o r t h  c o a s t  where  K e l l e y Its  1982,  ( I i1964;  ( T a t t e r s a l l  Kopache  g e n e r a l i z e d  America  r i v e r s  t h e Sacramento  1979)  1971;  a l o n g  intermedia  seem  s i z e ,  c o a s t  and  V i j v e r b e r g  and  would  e t  O r s i  1983;  i n c l u d e  maximum  marked  and  d i f f e r e n c e s  2-3  between  i o n s .  N. coast  a l . A  i n  1975; Pezzack and  N.  A l a s k a  s p e c i e s  1957; Murano  1979; S i e g f r i e d  1973);  t h e c e n t r a l  s i m i l a r  K n i g h t  mercedis  a l o n g  a r e  and  t h e east  and  they  Burns  ( T a t t e r s a l l  A s i a  These  and  N.  (Holmquist o f  Europe  a l o n g  .1971);  1964).  Kost  i n  americana  a w a t s c h e n s i s  Wigley  1974;  i n t e g e r  Burns  1955; H u l b e r t  1971;  a l .  N.  c o a s t  N.  e q u i v a l e n t s : h a b i t a t  N.  l i f e  i t i s a  1966; Levy h i s t o r y  d i s t r i b u t i o n , (Heubach  San  as  e t  has  e s p e c i a l l y t h e F r a s e r  J o a q u i n  major  i n t h e  1969;  and  such  -  i n n e a r s h o r e  a l . been  prey  S i e g f r i e d  d e s c r i b e d  e t  ( N o r t h c o t e  -  a l _ .  and  a t  f i s h e s  N o r t h c o t e  t h e southern  San 1979).  t h e  J o a q u i n S e v e r a l  west  reaches  e_t a l .  1969; S i e g f r i e d  f o r  1979; Levy  a l o n g  i n t h e lower  (Heubach i t e m  Sacramento  waters  1976) e t  (Turner 1981, l i m i t  of  a l . and  1982). o fi t s  r i v e r s t u d i e s  system have  8  c o r r e l a t e d measures  1983).  of  food  There  processes  a r e , however,  t h e  changes  lower  snowmelt  produces  a  out  marshes  i n t o  s p e c i e s  a  (Levy  a  these  rear  of  e s t u a r y the  few  i n t h e e s t u a r y  1979).  composition  t h e and  on  summer,  produce  i n t e n s i t y  and  s i z e - d i s t r i b u t i o n  1973)  same and  i n c r e a s e s b e n t h i c the  time,  s i g n i f i c a n t  primary  i n  w i t h  concert which  e s t u a r y  t o  f i s h  a  s p r i n g , estuary  number  weeks  organisms  Yesaki  N.  food  i n  of  Lasenby  t h e  changes can  i n  (Takahashi  The  (Levy  be  At  e_t  a l .  g e n e r a l l y  abundance N.  i n  t h e  mercedis.  1979)  of  (Levy  community,  on  t h e  changes  t h e  changes  algae  and  water  r e s i d e n t  temperatures.  (Johnston  River  b r a c k i s h  t h e above  p r e d a t i o n  t h e  s a l t  1974);  other  with  i s t h e p r i n c i p a l  i n  t h e  through  seasonal  and  by  p r e d a t o r s  f i s h e s  by  i s d r i v e n  t h e F r a s e r  days  t h e  p r o d u c t i o n ( K i s t r i t z  R i v e r  by  of  macrophytes  meiofauna,  F r a s e r  and  of  i n t h e e a r l y  move  mysids  sequence  consequence,  f i s h  of  of  Orsi  demographic  f l u s h e s  a  (Northcote  coupled  t o  of  p e r i o d  abundance  t o  and  r i s e  t h e  As  salmon  growth  e x p e c t e d  the  which  Moreover,  f o r a  and  of  t r a n s f o r m i n g  months  f e e d i n g  Breeding  throughout  drainage  i n d i s c h a r g e  j u v e n i l e  a  1982)  temperatures  i n t e r i o r  1979).  of  environments  environment.  a l .  Knutson  p r e d i c t a b l e  t h e assemblage  m i l l i o n  Northcote a l .  of  e t  p e r i o d  As  e s t u a r y ,  freshwater  hundred  over  et  t h e  1978;  abundance  s t u d i e s  a  b i o l o g i c a l  i n c r e a s e  composition  s e a s o n a l l y s e v e r a l  of  t h e  i t s  p o p u l a t i o n s .  R i v e r ,  c y c l e .  from  1 0 - f o l d  d e t a i l e d  mercedis  and  i n  (Anonymous  no  Fraser  temperature  s p r i n g ,  and  i n N.  i n t h e p h y s i c a l  annual  wedge  f l u c t u a t i o n s  resources  o p e r a t i n g  In  the  year-to-year  of  mercedis 1982),  i n  a l s o  9  i n c r e a s e s As l i k e l y  from a  to  spring  be  exposed  abundance,  and  f e c u n d i t y . and  T h i s  s i z e  and  d i f f e r e n t  f a c t o r s  which  w i l l  should  and  Aims  age of  f l u c t u a t i o n s f a c t o r s  The in  the  under  mysid  attempts  s p e c i f i e d and  l i f e  to  w i t h  has  the  v a r y i n g  and the  how  to  l i f e  i n v o l v e s  of  and  to  energy  the  s i z e  account i n  for  terms  w i t h i n  and  (3)  to  by  r e l a t e  of  t r a i t s  w i l l  vary  approach  i s  w i t h i n  of the  a l l o c a t i o n  body  c o n t r a s t s  such  i n f l u e n c e  mysid  e x t e n s i v e  My  Neomysis  may  (1)  the  of  are  above.  t r a i t s  p r o c e s s e s  h i s t o r y  c o n d i t i o n s .  s u r v i v o r s h i p  h i s t o r y  regimes,  the  and  which  death  demographic  p r e d a t i o n  b r e e d i n g ,  of  p a t t e r n s  of  summarized  goals:  abundance  v a r i a t i o n  p r e d i c t  main  are  T h e s i s  l i f e of  mysid  b i o l o g y  f a c t o r s  t h r e e  examine  i n  the  c h a r a c t e r i s t i c s  the  p o p u l a t i o n  frequency  b i r t h  and  h i s t o r y  of  of  a l t e r  p r e d i c t i o n s  v a r i a t i o n  w i t h  e n v i r o n m e n t a l  d e s c r i p t i v e ,  the  n u m e r i c a l  h i s t o r y to  w i t h  work  a f f e c t i n g  l i f e the  regimes  d i r e c t l y  O r g a n i z a t i o n  and  the  (2)  to  m a t u r i t y ,  young,  p o p u l a t i o n ,  that  and  d e a l s  at  t r a i t s .  observed  conform  e s p e c i a l l y  number  these  q u i t e  in  1981).  g e n e r a t i o n s  to  t h e s i s  m e r c e d i s ,  (Harrison  d i f f e r e n t  V a r i a t i o n  The  as  summer  consequence,  food  expected  to  theory under  comparative and  between  p o p u l a t i o n s . The  f i r s t  c h a p t e r  e s t u a r i n e  p o p u l a t i o n  a t t e n t i o n  to  of  v a r i a t i o n  m o r t a l i t y  r a t e s .  i n f l u e n c e  b i r t h  I  a l s o  and  documents N. i n  m e r c e d i s , l i f e  examine  death  the and  h i s t o r y the  p r o c e s s e s  l i f e  h i s t o r y pays  i n  the  an  p a r t i c u l a r  c h a r a c t e r i s t i c s  proximate  of  f a c t o r s p o p u l a t i o n .  and  i n  which The  10  second  chapter  p h y s i o l o g i c a l p a t t e r n s  and  examines  the  p r o c e s s e s compares  which the  demographic  regimes  w i t h  The  chapter  examines  h i s t o r y  t r a i t s  and  f i n a l i n  l i f e  p o p u l a t i o n  of  N.  m e r c e d i s .  p r e d i c t e d  d i f f e r e n c e s a  i n f l u e n c i n g  determine  p a t t e r n s  those  i n  f a c t o r s  seen  energy  a l l o c a t i o n  under  d i f f e r e n t  by  l i f e  i n  a l l o z y m e  f r e s h w a t e r  and  the  a  h i s t o r y  t h e o r y .  f r e q u e n c i e s  b r a c k i s h  water  11  CHAPTER  1. IN  THE THE  POPULATION  TIDAL  DYNAMICS  MARSHES  OF  THE  OF  Neomysis  FRASER  mercedis  RIVER  HOLMES  ESTUARY  T n t r o d u c t ion  Neomysis in  e s t u a r i e s  c o a s t et  of  Levy the  r i v e r s  et  a l .  Sacramento i t s range,  The w h o l l y year  S e v e r a l  however; are and  l i f e  have  w e l l  food  the  have  c o u l d  as  i n  account  suggest  the  the  mercedis  l i f e i n  the  that are  h i s t o r y t i d a l  or  the  f a c t o r s  p r o c e s s e s  the  marshes  The  f e c u n d i t y  d r i v i n g  of  to  not  f l u c t u a t i o n s  i n  are  have  demographic  seen  r e l a t e d  p o p u l a t i o n s .  the  i n  y e a r - t o -  1983).  of  f a c t o r s  c h a r a c t e r i s t i c s  l i m i t  mysids  abundance  mysid  i n  1979). of  through  f o r  o n l y  southern  O r s i  s t u d i e s  a f f e c t i n g  s h o u l d  and  i n  1977;  f l u c t u a t i o n s  mercedis  be  f i s h e s  a l .  et, a _ l .  determine  p r o c e s s e s  f a c t o r s  N.  P a c i f i c  s t u d i e d  the  common  N o r t h c o t e  e_t  abundance  Knutson  would  these  at  the  many  suggested  of  death  h i s t o r y  N.  determine  1978;  been  S i e g f r i e d  abundance  f o r  N o r t h c o t e has  i s  1973;  s e a s o n a l  d e t a i l e d  determined of  l a r g e  s t u d i e s  item  system,  no  p o p u l a t i o n s  changes  p o p u l a t i o n  the  which  the  as  I  i n  prey  which  a l o n g  Holmquist  h i s t o r y  1969;  mysid  r i v e r s  1966;  R i v e r  i t showed  which  b i r t h  abundance i n  J o a q u i n  (Heubach  There  of  important  l i f e  San  of  1969;  I t s  through  mercedis  an  (Anonymous  s u r v i v a l .  knowledge  (Heubach  i s  water  reaches  1979).  unknown.  i n f l u e n c i n g  lower  K e l l e y  s i z e  s p e c i f i e d ,  b r a c k i s h  and  -  l e v e l s  a  (Turner  f a c t o r s  mechanisms been  I t  f l u c t u a t i o n s  food  the  where  and  i s  America  1976).  abundance  N.  and  North  a l .  c o a s t a l  of  mercedis  A i n i n  seasonal  p o p u l a t i o n s .  an of  e s t u a r i n e the  F r a s e r  12  R i v e r  d e l t a .  r e l a t e d  in  t o  of  from  rates  a s s e s s  the  r e l a t i v e  S i t e  l i f e  m e r c e d i s  d e n d r i t i c ,  t i d a l  123°08'W),  a  1979). d a i l y ,  r i v e r  t o  the  of  of  these  r a t e s  and  food  and  f a c t o r s  p o p u l a t i o n .  w i t h i n  the  p r e d i c t i o n s  V a r i a t i o n  p o p u l a t i o n of  as  l i f e  were  h i s t o r y  Methods  meters  c e n t r e s  of  c u r r e n t and  d e t e r m i n e d  of  channel  the  The  depths  by  the  below  the  channel  c o n s i s t o t h e r  of  0.5  low  banks, g e n e r a l  low  or  March  at  m,  whose  g r a d i e n t  the  u s u a l l y  l a r g e ,  (49°06'N,  w i t h  on  s e r i e s  lower  i s l a n d  F r a s e r  R i v e r  a  p l a n t  ( K i s t r i t z  f l o o d  depending  the  t i d e of  h e i g h t  b r a n c h i n g may  up  t o  m  o t h e r  a r e a s  of  w h i l e  the  a r e a s  and  are  30  be wide.  r e l a t i v e l y  s i d e s ,  s i l t s .  and  i s l a n d  reaches  e l e v a t i o n  sands,  a  i n t e r t i d a l of  a  monthly  I s l a n d  l y n g b y e i  v i a  and  1979  r e l i e f ,  Carex  p o p u l a t i o n  b i - w e e k l y  Woodward  i s  bottoms f i n e  on  t i d e s  D r a i n a g e  w e l l - d e f i n e d  and  of  sedge  about  from  e s t u a r i n e  marshes  i s  s e m i d i u r n a l of  an  u n d i s t u r b e d  t i d a l  i s l a n d  of  1977  r e l a t i v e l y ,  1 ) .  the  demography  October  d i s c h a r g e .  s e v e r a l  reaches,  and  d r a i n a g e  M i x e d ,  w i t h  h i g h e r  and  dominated  channels  The  M a t e r i a l s  between  part  ( F i g u r e  community  and  the  were  s m a l l ,  forms  twice  w i t h i n  death  abundance  importance  of  h i s t o r y  made  Yesaki  the  and  1976).  c o l l e c t i o n s  e s t u a r y  viewpoint  b i r t h  D e s c r i p t i o n  Neomysis  which  change  t o .  c h a r a c t e r i s t i c s  the  (Stearns  The of  the  h i s t o r y  examined  Study  i n  demographic  l i f e  theory  m e a s u r e d . i n s t a n t a n e o u s  v a r i a t i o n  p r e d a t o r s agents  I  The  upper lower  Figure  1.  Map o f  the  location  of  Fraser  Estuary  Estuary  and D e l t a w i t h  and d e t a i l s  of  insets  Woodward  showing  Island.  general  14  reaches depth  of  the  at  scoured  low  i n t o  a  e x c e p t i o n a l l y of  v a s c u l a r  in  green  mouth  t r o u g h ,  t i d e s .  about  2  192  (Levy  Mm  m  v a s c u l a r  at  m,  the and  C o l l e c t ion  The  mysid  long  b e f o r e  tows  the  a l o n g  h i g h .  net  was  /im  mesh  The  r e l a t e d of  the  116  are  reaches  known  mesh 1  water  c e n t r e  which  i s  o f t e n  d r a i n  c o m p l e t e l y  the  channel  reaches  i s  and  on  devoid  spp.  d u r i n g  m u d f l a t s  was  2  4610  m ,  1981).  495  a  mid-channel  occur  midsummer. f i l a m e n t o u s  Yesaki  f u r t h e r  1979)  m  long,  maximum  mean  Concurrent and  i n f o r m a t i o n  to  mysid's  p a t t e r n  (Appendix the  at  the  m  study low  net long  which and  w i t h  depth s i z e  s t u d i e s  of  f i s h  (Levy  about  the  a of  sediment  of the  et  a l .  s i t e .  of  ended  the  showed  that  channel  a l o n g  the  cm a  a  1963).  and  30  and  c u r r e n t  d i s t r i b u t i o n  j u s t  the from p r i o r  cm  p l a n k t o n  P r e l i m i n a r y from  or  r e p l i c a t e  d e t a c h a b l e  emigrated  bottom  at  sled-mounted,  wide  v e r t i c a l  they  2-4  i n t e n s i t y  o u t m i g r a t i o n  1)  w i t h  50 i n  sampled  making  bottom was  Herman  was  by  L i g h t  i n f l u e n c e 1969;  s i t e  t i d e  mid-channel  s c r e e n i n g .  (Heubach  of  m  Potamogeton  Channel")  daytime  the  mysids  c h a n n e l s  of  of  the  of a  and  p o p u l a t i o n  mm  speed  and  p r o v i d e  1.1  w i t h  area  ( K i s t r i t z  r e c t a n g u l a r ,  cup  most  0.3-1  Methods  immediately m  an  mouth,  communities  may  lower  ("Stump  N o r t h c o t e  p l a n t  the  but  on  r e t a i n  t i m e s .  s i t e  20  i n  stands  the  n o t i c e a b l e  sampling of  i n  at  u s u a l l y  Although  s c a t t e r e d  areas  occur  w i d t h  1979)  s h a l l o w  are  algae My  e s p e c i a l l y  p l a n t s ,  f i l m s  channels  t i d e ,  low  backwater  Diatom  10  p r i n c i p a l  of  s t u d i e s  dewatering the to  upper the  15  d r a i n i n g ensured to  of that  the  that  e n t i r e  the  m  the  the  s i n c e  i n  and  downstream  the  s a m p l i n g i n  which  r e t a i n e d  Stump  because  the  t r a n s p o r t  channel  d i d  that  p o p u l a t i o n mysids  w i t h i n  at  low  not  a v a i l a b l e  made  i n  t i d e .  change  e m i g r a t e d be  e s t u a r y  as  f l a t  I  assume  a p p r e c i a b l y  channel  not  the  r e l a t i v e l y  the  should  the  a  c o n s e q u e n t l y  was  were  had  water  Channel  o c c a s i o n s whole  the  regime  c o l l e c t i o n s  c h a n n e l ,  i n f r e q u e n t  bottom  The  g e n e r a l l y  p o p u l a t i o n  The  p o p u l a t i o n  g e a r .  of  which  c o m p l e t e l y the  the  100  and  a f t e r  c h a n n e l .  s a m p l i n g  lowermost bottom  the  a  d r a i n e d u n i t  a l o n g  s u b j e c t  t o  net  ( S i e g f r i e d  e_t  a l .  the  s l e d  1979). To in  m i n i m i z e  mid-channel  downchannel s l e d  t o  me  the the  w i t h  0.7  I  m).  (about  (#-m of  10  m  2  nets  edge  u s u a l l y  - 2  )  of  a r e  1968;  known  s i z e  mysids  and  r e s u l t s  used  t o  tow  i n  the  i n  the  a c c e s s i b l e a t of  shore,  q u i c k l y 5  m  w i t h  10%  them  same  of dry  might  changed  water  depth  range.  t o  s i z e - s e l e c t i v e ,  because  and  mesh  determined c o r r e c t  r e t e n t i o n  The  the  r e l a t i v e i n  the  the  h a b i t a t . i c e ;  one  Because vary  as  w i t h  t i d e (0.3-  c o n s t a n t  of  s i z e -  ( C l u t t e r  c a p t u r a b i l i t y  f i e l d  d e n s i t y  towed  depth  roughly  be  channel  2  walked  f o r m a l i n .  channel  t o  the the  then  f i e l d i n  p l a c e d  t o  sampled  p r e s e r v e d  1968).  was  bank,  I  was  a v o i d a n c e  Vannucci  d i f f e r e n t  Each  sample  t h i s  m y s i d s ,  r e t u r n e d  the  mysids  area  the  me, of  was the  t o  by  frozen  channel  over  gear  of  l i n e .  u n d r a i n e d  m )  d i f f e r e n t i a l  the  the  attempted  1050  Anraku  front  the  The  Towed  a v o i d a n c e  c o l l e c t i o n  d e n s i t y area  a  were  per  h e i g h t ,  i n  along  Samples sample  gear  and  (Appendix  and of 2)  s i z e - f r e q u e n c y  16  d a t a . V e r t i c a l w i t h  a  YSI  s u r f a c e the  j u s t  of  The  and  33  of  temperature  T-S-C  above  meter the  at  and  s a l i n i t y  i n t e r v a l s  channel  bottom  of  were  0.5  about  m  measured from  one  the  hour  before  t i d e .  A n a l y s i s  u s i n g  model  and  low  p r o f i l e s  F i e l d  mysids  the  Samples  were  i d e n t i f i e d  d e s c r i p t i o n s  Holmquist  C h a r l o t t e  and  (1973).  Holmquist  of  keys  The  as of  Neomysis  Holmes  (1897),  i d e n t i f i c a t i o n  the  Swedish  were  thawed  mercedis  Museum  was of  Holmes  Banner  (1948),  confirmed N a t u r a l  by  Dr.  H i s t o r y ,  Stockholm. Frozen animals  samples  s o r t e d  from  which  the  mysids  t h e i r  e n t i r e t y .  subsampling 400  w i t h  a n i m a l s ,  c o l l e c t i o n sample  was  d i d  were  s i z e d  0.02  mm  same  l i v e ,  were  d e b r i s  very  a by  Folsom  l e s s  d i f f e r  at  50X  measurements  of  t h i s .  of  and  the  the  p r e s e r v a t i o n  The  biomass  (mg  i f  exopod  of  = the  dry  2  weight'in" )  i n  determined  by  about i n  the  from  the  same  p e r i o d s of  the  r a n k i n g s  p<0.05). to  Animals  the  nearest  measurements  animals uropod up  to  mysids  300-  t o t a l  drawn  uropod  S e q u e n t i a l  f o r  counted  o b t a i n  the  0.82,  s c l e r o t i n i z e d  technique  were  the  a g a i n s t  s i z e - f r e q u e n c y  f o r m a l i n - p r e s e r v e d  h e a v i l y  to  and  t r a y ,  were  Subsamples  concordance  the  white  Samples  s p l i t t e r  t h e i r  m a g n i f i c a t i o n .  f r o z e n ,  s h a l l o w ,  a l l animals  i n  f o r m a l i n  d i s t r i b u t i o n s  p l a n k t o n  than  measuring  a  10%  c o n s p i c u o u s .  measuring  c o e f f i c i e n t by  i n  S i z e - f r e q u e n c y  not  ( K e n d a l l ' s  w i t h  or  the  i n t o  showed d i d 1  not  on  the that  change  y e a r . on  a  given  .17  date  was  estimated  d i s t r i b u t i o n  using  from  t h e  measured  length-weight  r e l a t i o n  c o l l e c t e d ,  animals  them,  l i v e  r i n s i n g  weighed  them  aluminum  the  nearest  over  c a l c i u m  /ug.  s t a b i l i z e d  a t  w i t h i n and  mean  g r a v i d  removed  from  Females  showed  s i g n s  B e r r i l l  w i t h  V.  somatic  when  male's  were  f o r embryo l o s s .  except  A d u l t  males  Animals f o l l o w i n g  were  c r i t e r i a (1)  weighed  t h e d r y  weight  a  stream  counts  that  mean  breeding The  as  had  o f  were  as  was  and  a  as  mass  minimal  from  a  and  combined  t h e  u s u a l l y  sperm  eggs  c a t e g o r i z e d  determined  c o n d i t i o n  t h e  marsupia  VI  weights,  were  F r e s h l y  water  were  h i s stage  cottony  above,  and  c l o s e d  stages  egg  embryos  season.  above  w i t h  weight)  water.  female  d e s c r i b e d e j a c u l a t e d  was  e a s i l y  measure  of t h e  e f f o r t .  c a t e g o r i z e d  a s  ( m o d i f i e d  from  j u v e n i l e s  c h a r a c t e r i s t i c s .  t o  d e s i c c a t o r  and  of  as  Embryonic  (body  r e p r o d u c t i v e  i np r e them  i n a  showed  breeding  k i l l e d  t h e marsupium  weighed,  measuring  them  temperature  t h e  i n  f r e s h l y  weighing  s t o r e d  throughout  (1969),  water,  and  were  room  k i l l i n g  d r y i n g  measurements  weight  and  water,  The  p e r i o d .  t i s s u e  c o l l e c t e d  by  d r y weight  egg  i n warm  t o  r e l a t i o n .  warm  measurements  weights,  immersed  i n  animals  C l u t c h  above.  determined  f o r 15-18h,  t o cool  used  of  f o l l o w i n g stage  d r i e d  females  p i p e t t e . no  60°C  s i z e - f r e q u e n c y  length-weight  d i s t i l l e d  t h e d r y i n g  i n t e r v a l s  c o l l e c t e d g e n t l y  The  c o r r e c t e d  immersion  P r e l i m i n a r y  Counts made  by  a t  c h l o r i d e  immediately.  was  w i t h  pans  t h e  -  Animals  animals w i t h  t o  sex and  Reynolds which uropod  m a t u r i t y and  lacked  u s i n g  DeGraeve  1972):  a l l secondary  l e n g t h s  <  1.35  t h e  mm  sex c o u l d  18  not  be  sexed  r e l i a b l y  and  were  t h e r e f o r e  a l l  c l a s s e d  as  j u v e n il e s ; (2) (a)  a  male  immature  process  1951,  p.19),  f u l l y  developed,  s c a t t e r e d  (b)  s t o u t (3)  c h e l a e  the  ampullae specimens)  as (4)  l a t e r a l l y  f u l l y  p e n i a l w e l l  pleopod  possessed and  w i t h  c y l i n d r i c a l  animals  the  any  of:  T a t t e r s a l l  the  exopod  penes  sacs  as  and  males (not  h e a v i l y  not  b e a r i n g  -  at  marsupium 1951,  pleopod,  and  0.25  of  l e n g t h  the  had  the  sperm  v i s i b l e  v i s i b l e  male  i n  of i n  the  p r e s e r v e d  p r o c e s s e s ; p o s s e s s i n g  d i r e c t e d base  f o u r t h  f i f t h  animals  the  elongate  the  always  forward  T a t t e r s a l l  >  setose  females  o r i g i n a t i n g  p o s s e s s i n g  t i p of  developed  immature  and  -  Breeding  appendages;  ( T a t t e r s a l l  which  ( T a t t e r s a l l  f o u r t h  p a i r e d  males  compressed,  ( o o s t e g i t e s ) t h o r a c i c  (c)  beyond  exopod.  and  animals  antennules  biramous  mature  w i t h  of  -  setae;  e x t e n d i n g  rest  a  the  or  pleopods, the  on  males  of  two  marsupial the  l a s t  two  incomplete;  s t e r n a l  p.14)  p o s t e r i o r  on  p a i r s  the  of  p l a t e s p a i r s  of  p r o c e s s e s t h o r a c i c  segments; (5) rounded,  c l o s e d (6)  the  mature  marsupium  non-breeding  marsupia  g r a v i d  ,  but  females  -  females  without animals  -  animals  w i t h  l a r g e ,  embryos; w i t h  embryos  present  i n  19  Demographic  Analyses  Instantaneous the  egg  r a t i o  1982). Lynch  method  c a p i t a  b i r t h  and  p o p u l a t i o n s  i n which  hatch  as  e s t i m a t i n g n a t u r a l  f r e e - l i v i n g  p o p u l a t i o n s  a r e  furthermore  1979;  more  they  r a t h e r  number  T a y l o r  g e n e r a l  a l l o w than  i n  e s t i m a t e s  y i e l d i n g  c u r r e n t  S l a t k i n  be  made  u n t i l  methods  r e s t r i c t i v e Lynch's  methods  s e p a r a t e l y  s i n g l e  f o r  breeding  1981).  competing  t o  a  embryos  m o r e - o r - l e s s  and  than  breeding  c o n t i n u o u s l y  of  a f t e r  i n s t a n t a n e o u s  c o n t i n u o u s l y  A l l  Lynch  c a l c u l a t e d  d e v e l o p i n g  young.  a  t o  u s i n g  1974;  e s t i m a t i n g  the  parameters  r e q u i r e  ( S e i t z  t e c h n i q u e s  c a r r y  c a l c u l a t e d  were  a p p l i c a b l e  females  demographic  assumptions  c l a s s e s  a r e  for.  were  Paloheimo  rates  procedures  r a t e s  rates  1974;  m o r t a l i t y  Lynch's  death  b i r t h  (Edmondson  Instantaneous (1983).  they  per  and  by  s i z e  p o p u l a t i o n - a v e r a g e d  e s t i ma t e . The  i n s t a n t a n e o u s  c l a s s  i s a p p r o x i m a t e l y  [3]  m(i)  » -  where time  N ( i , t ) t , and  c l a s s The  i  m o r t a l i t y (Lynch  [ l n { N ( i , 0 ) [ G ( i , i + 1 )  i s the G ( i , j )  which  d e r i v a t i o n  G ( i , i + 2 ) ]  i s t h e  [3]  g r e a t e r  than  t h e  uropod  s i z e  c l a s s e s  i n t o  of  r e q u i r e s  expected of  mm  of  c l a s s that  growth  0.5  }  +  i - t h  s i z e  -  G ( i - 2 , i ) ] • e x p ( - m ( i ) • t / 2 ) l n { N ( i , t ) } ]  animals  number s i z e  m ( i ) , f o r t h e  1983)  [ G ( i - 1 , l )  d e n s i t y  grow of  +  +  r a t e ,  i n  t h e  animals j the  over  between  /  t  i - t h s i z e i n i t i a l l y  over  t h e  time  s i z e  c l a s s  t h e  i n t e r v a l  0.3  c l a s s  and  3.8  i n  s i z e  i n t e r v a l  width  mm  a t  be  t . were  t .  much Thus used.  20  The  expected  d e r i v e d  growth  from  (chapter  r e a r i n g  2 ) .  m o r t a l i t y  P r i o r  r a t e s by  parameter  v a l u e s ;  i s  t o  f o r N.  e s t i m a t o r  The  i n c r e m e n t s  a p p l y i n g t h e  determine  e x p e r i m e n t s  which  using  t o  [3]  m e r c e d i s , i t  t o  a s s e s s e d  c a p i t a  G ( i , j )  r e p o r t e d s i z e  t h e  s p e c i f i c  a c c u r a c y  of  of  i n Appendix  b i r t h r a t e  were  elsewhere  p o p u l a t i o n s  a r e d i s c u s s e d  per  1982)  I  a r e  e s t i m a t e  s i m u l a t e d  r e s u l t s  i n s t a n t a n e o u s  (Lynch  which  f o r t h e  t h e  known  3. p o p u l a t i o n  i  max [4]  b  =  I  P ( i ) • b ( i )  i=l  where s i z e  P ( i ) i s t h e p r o p o r t i o n c l a s s ,  and  c a p i t a  b i r t h  [5]  b ( i ) =  where  E ( i )  c l a s s  ( t h e  E ( i ) - [ r ( i )  i s egg  of  Lynch's  b i r t h  h a t c h i n g  per  t h e  rate  t o t a l  p o p u l a t i o n  s i z e - s p e c i f i c  i m p l i e d  by  youngest was  m ( i ) ] /  number  i n t h e i - t h  i n s t a n t a n e o u s  r a t e  t h e s t a g e s s t a g e s t h e  of  and  e s t i m a t o r  female of  [ e x p ( D - [ r ( i )  eggs  r ( i ) i s  f o r changes  a d u l t  i n t h e  developmental  t h e  +  i - t h c l a s s ,  day  from  m o r t a l i t y  t h e  r a t i o ) ,  v a r i a t i o n  the  i s  t h e  per  r a t e ,  i n c r e a s e  r e s u l t  b ( i )  of  D  per  i n d i v i d u a l  t h e  c o r r e c t s  l a y i n g .  t h e  The  not  egg  of  t h e  i n my  was  s t r o n g l y  a t  a l lt i m e s .  p r i n c i p a l  cause  This of  1]  f o r  age  of  p e r i o d .  f r a c t i o n  p r o p o r t i o n s samples  rate  of  d i s t r i b u t i o n  but  -  f o r t h e i - t h  development  age  m o r t a l i t y ,  egg  m ( i ) ] )  i n s t a n t a n e o u s  i s t h e egg  i n t h e egg  +  eggs which  temporal  d i s t r i b u t i o n  d i f f e r e n t  embryonic  skewed  suggested non-uniform  towards  that egg  a d u l t age  21  d i s t r i b u t i o n s , i m p l i c i t  i n  The rates  t h a t ,  Lynch's  egg  used  p e r i o d  and  a l g o r i t h m  e s t i m a t e  i n  [5]  were  average  on  the  sampling  estimated  from  in  experiments  the  Approximate were  e s t i m a t e d  were  by  of of  of  the  w i t h i n  the  i n f l u e n c e  a n a l y s i s  and  comprise  the  mercedis  the  d i v i d e d  1  f o r  over  the  Egg  egg  m o r t a l i t y development  development  r e l a t i o n s h i p  the  b i r t h  technique  and  was  o b t a i n e d  e r r o r  g i v e  death  rates  the  rates  which  randomly  procedure  r e s u l t i n g  e s t i m a t e s  i n  a f t e r  standard The  (Johnston  c a l c u l a t e d  as  l i n e a r  of  drawing  from the  c e n t r a l  measures  a l l  normal  observed 95%  of  and  sampling i n  of  was  examined  the  Lasenby  mean  q u a n t i l e s  the  p r e c i s i o n  on  f e c u n d i t y  I f  be  then  on  s u b s t r a t e s  abundance,  or  r a t i o  of  i . e . , (2)  can the  the  meiofauna  at be  meiofauna  p o p u l a t i o n  H a r r i s o n  a v a i l a b i l i t y s t o c k ,  b e n t h i c  c o n s t r u c t e d  by  food  c o r r e l a t i o n  s e v e r a l  r e p o r t e d s i m i l a r  u s i n g  e s t u a r i n e  1982),  can  s t a n d i n g  the  a v a i l a b i l i t y  r e g r e s s i o n .  a v a i l a b i l i t y  c a p i t a mysid  r a t e s  food  abundances  per  r e s o u r c e  m o r t a l i t y  v a r i a t i o n  by  food  p r i n c i p a l  contemporaneous Seasonal  of  stepwise  r e s o u r c e  meiofauna  (1)  l i m i t s  e s t i m a t i o n  parameters.  i n s t a n t a n e o u s  food  i n s t a n t a n e o u s  d a t e .  r e - e s t i m a t e d  ±  of  and  2 ) .  C a r l o  the  those  e s t i m a t e s .  The  N.  i n  d i s t r i b u t i o n  the  and  Monte  beyond  unnecessary.  dependent  (chapter  (n=l00)  used  d i s t r i b u t i o n s values  a  adjustments  v a l u e s  temperature  c o n f i d e n c e  r e p e a t e d l y  parameters  were  development  ending  r e a r i n g  t h e r e f o r e ,  a  i n d i c e s u s i n g  of the  (1981)  f o r  nearby  s i t e .  r e p r e s e n t e d  meiofauna  to  by:  abundance  supply:demand abundance  of  the  index d a i l y  22  consumption i n g e s t i o n  C  e s t i m a t e d  e q u a t i o n  f o r  the  (Johnston  and  mysid  p o p u l a t i o n  Lasenby  1982)  summed  from  the  over  s i z e  c l a s s e s :  i C  =  24  •  max  I  0  3 . 8 1 - N ( i ) - W ( i )  '  7 8 2  5 1 5  - T ° '  /  w(p)  i=l  where  N ( i )  average  i s  the  dry  weight  temperature,  and  supply:demand mysid's s i z e  abundance  w(p)  index  temperatures t h e r e f o r e  as  t o  caught  at  1979).  B i a s  the  t e c h n i q u e  abundances been  c o n t a i n  same the  consuming  f o r  mid-October  T  The  the  the  i s  the  r e s u l t i n g i n  the  abundance  and  i n  and  ambient  abundance.  I t  may  a v a i l a b i l i t y  of  food  caught  of  those which  mercedis  were  t o  October  of  not  measured  stomach  was  most  s p e c i e s  r e s u l t i n g  the  samples  or  1977  as  ( b l o c k a g e  the  mercedis N.  i s  v a r i a t i o n i n  prey  r e l a t i v e  the  time  those  Subsamples N.  w e i g h t .  p o p u l a t i o n i n  r a t e s  from  f i s h  s e i n e )  a d j u s t e d  1979).  m o r t a l i t y  used  of  prey  W(i)  i - t h c l a s s ,  changes  mysid  the  the  c l a s s ,  s e a s o n a l  from  v a r i a t i o n  s i z e  m y s i d s .  the  fine-meshed  as  d i r e c t l y  i n  i n  average  the  r e f l e c t  the  e s t i m a t e d  the  i - t h  mysid  r e s u l t i n g  w e l l  S i z e - s p e c i f i c were  i s  of  b e t t e r  r e s o u r c e s  a  the  i n c o r p o r a t e s  r e q u i r e m e n t s s t r u c t u r e  of  of  samples  p r o b a b l y  p r e d a t i o n of  f i s h e s  (Levy  e_t a l .  n e g l i g i b l e  s i n c e  the  d e w a t e r i n g  channel  of  the  p r e s e n t .  f u l l y  f i s h  f i s h  r e t a i n e d  by  e f f i c i e n c y s p e c i e s  r e p o r t e d  examined 1978.  f i s h  c o n t e n t s  mysid  gear  were  from  F i s h  at  by  which Levy  monthly of  each  the  (Levy were e_t  w i t h  net  a The  have  et_  a l .  noted  t o  a_l.  as  i n t e r v a l s  from  s p e c i e s  were  23  chosen the  t o  span  o c c u r r e n c e  s p e c i e s if  of  were  t h i s  t h e a v a i l a b l e d i f f e r e n t  examined  on  was  n e c e s s a r y  d i s t r i b u t i o n .  Stomachs  the  esophagus  were  and  and  v i s u a l l y  by  sexed  p r e v i o u s l y  The f i s h  stomachs  observed  s e r i e s  on  of  S i z e - s p e c i f i c  a  S ( i )  in  stomachs,  of  my  more  of  f i s h  means The  each  prey  a  done s i z e  i n c i s i o n s  stomach  mercedis  be  mysid of  t o  of  might  t h e  a t  c o n t e n t s  type  e s t i m a t e d  were  measured  and  of  N.  mercedis  from  c o n s t r u c t e d  by  w e i g h t i n g  d i s t r i b u t i o n  date  was  f i s h  i n t h e  i s t h e A  - 2 - l n { l  t o t a l  -  E x p r e s s i o n  of  one  t i d a l  cycle  i s N ( i , 0 ) • [ 1 - p ( i ) ] The  t h e  where  c o n s e c u t i v e - d a y  sampling  Levy,  rates  were  a t  i - t h s i z e  mysid  Then  average  mysids  u n p u b l i s h e d ) . e s t i m a t e d  of  s i z e  c l a s s  t h e  time  of  c l a s s  simply  b e i n g  t h e p r o b a b i l i t y  c y c l e .  m y s i d s .  a  t h e  (D.A.  a r e a  [6] a r i s e s  of  over  t h e  by  t h e  as  S ( i ) / [ A - D ( i ) ] }  number  of  s p e c i e s  two  date  i s t h e channel  L e t p ( i ) be  i  N.  sampling  p r o b a b i l i t y  c l a s s  A l l  s p e c i e s  c y c l e s ) .  s i z e  by  s p h i n c t e r .  f o r each  D ( i ) i s t h e d e n s i t y  t h e  removed  frequency  m ( i ) =  environment.  a l t h o u g h  i n s t a n t a n e o u s m o r t a l i t y  where  10-20  c h a r a c t e r i z e  were  given  each  [6]  and  date  p r o p o r t i o n  d e s c r i b e d .  s i z e  i n c l u d i n g  t h e  t o  i n rough  G e n e r a l l y  t h e percentage  d i s t r i b u t i o n s  abundance  each  d i s p l a c e m e n t .  o v e r a l l  range  s i z e s .  t h e p y l o r i c  c a t e g o r i z e d  as  s i z e  eaten of  number  N ( i , 0 )  p r o b a b i l i t y  from  a  over  i n t h e  c o n s i d e r a t i o n a  day  mysid  (2  b e i n g over  i n i t i a l  s u r v i v i n g  found  s a m p l i n g ,  mysids  a  s u r v i v i n g  i s t h e of  of  i  one  t i d a l eaten t i d a l  number  over  2  of  c y c l e s  24  is  N ( i., 0) • [ 1-p( i ) ] • [ 1-p( i ) ] . N(i,1)  whence eaten  =  [ 6 ]  N ( i , 0 ) - [ l - p ( i ) ] - [ l - p ( i ) ] i s o b t a i n e d  i s t h e p r o p o r t i o n  by n o t i n g o f mysids  p(i) This eaten  d e r i v a t i o n  does  p r o p o r t i o n channel for  o f t h e mysids  found  a n d  f i s h  t h e  ( 4 )  stomachs,  i . e . ,  reasonable  s i n c e  t h e f i s h  u n t i l  f o r c e d  there  a r e s p e c i e s  (Levy  e t a l . The  e q u a t i o n  s(m)  eaten  t h e c h a n n e l .  on t h e r i s i n g  a n d  Levy  i n  being  have  been  s m a l l  i n t h e  (3)  a l l  t h e  a r e found i n than  t h e  assumptions a r e  t o m i g r a t e t o  t h e e b b i n g t i m i n g  a  w i t h i n  l e s s  o f t h e s e  g e n e r a l l y  t h e  i s  being  a d j u s t e d  1979),  i n t h e c h a n n e l  by  that  consumed  rate  o f  feeding  e_t a l _ .  a r e  Most  t o e m i g r a t e  d i f f e r e n c e s  o f  c y c l e ,  i . e . ,  (which  a r e o b s e r v e d  t i d e  one  (2) a l l f i s h  t h e e v a c u a t i o n  i n  over  c y c l e s ,  stomachs  a l l mysids  t h e p r o b a b i l i t y  (1) t h e p r o b a b i l i t y  e f f i c i e n c y ,  time  channel  t h a t :  t h e t i d a l  f i s h  N ( i , 0 ) - e x p [ - m ( i ) ]  A •D ( i) ] .  i n t h e samples  r e s i d e n c e  channel  eaten  a r e e a t e n ,  gear  i n  =  that  [ S ( i ) /  over  a r e r e p r e s e n t e d  c h a n n e l , the  =  assumes  n o t change  d i f f e r e n t i a l  mysids  B u t ,  i n t o  t h e  t i d a l  remain  i n t h e  t i d e ,  a l t h o u g h  o f  o u t m i g r a t i o n  1979).  s t a n d a r d  e r r o r  o f t h e m o r t a l i t y  [ 6 ] i sa p p r o x i m a t e l y  2  Om/9A) - s ( A )  2  +  ( B a i r d  2  r a t e s  1962,  Om/9D) - s ( D )  2  e s t i m a t e d  p.64):  2  +  where s ( A ) i s the s t a n d a r d e r r o r o f A , e t c .  ( 9m/3S  ) • s(S )  2  from  25  R e s u l t s  P h y s i c a l  Parameters  The t i d a l  channel  2b). 19  temperature  showed  Temperatures  and  21°C,  o c c u r r e d p e r i o d ;  t o  i n the  the  t i d a l  channel  being  the  maximum  from  the  temperature A l t h o u g h  v a r i a t i o n ,  the  ( K . J .  of  s a l i n i t y  were  r i v e r s a l t  the  and  e_t  f a l l - e a r l y  s p r i n g  l a r g e l y  were  6  ppt  r e s u l t e d the  1974). of  temperate  c o n s i d e r a b l e  the  bottom  r e l a t i v e l y Both  the  r e g u l a t e s  c h a r a c t e r i s t i c  of  d u r i n g  s a l i n i t y ,  which  showed  between water  (Hodgins  waters  and  S a l i n e  low  changes  r e a s o n a b l y  ajl.  of  d i s c h a r g e  d a t a ) .  t h e r e f o r e  ( N o r t h c o t e  were  the  2a  maxima  environment  s a l i n i t y  channel  the  i n  (Figures  4°C.  d u r i n g  wedge  was  s u r f a c e  u n p u b l i s h e d  c y c l e s  o c c u r r e n c e s  of  to  s a l i n i t y  c y c l e  temperature  reaches  H a l l ,  of  the  the  3  only  waters  midsummer  f r e s h w a t e r  The  c y c l e  p e n e t r a t i o n  of  bottom  v a r i a t i o n  from  i n t r u s i o n s  v a l u e .  s e a s o n a l  lower  minima  a  the  seasonal  channel  was  of  smoothly  water  l a t i t u d e s .  the  marked  midwinter  B r a c k i s h  The  s a l i n i t y  c y c l e d  summer.  upstream  and  the  d i e l  waters  s l o w l y  v a r y i n g  temperature  p r e d i c t a b l e  i n  and  seasonal  1975).  Abundance  P o p u l a t i o n 2 5 - f o l d  range  d e c l i n e d throughout  d e n s i t i e s  throughout  s h a r p l y the  i n  w i n t e r  the t o  of the  Neomysis y e a r .  autumn, reach  and  mercedis  The  abundance  c o n t i n u e d  minimum  f l u c t u a t e d  to  d e n s i t i e s  of  N.  d e c l i n e of  over  a  mercedis s l o w l y  30-40'm"  2  by  26  I — i — i — i — i — i — i — i — i — i — i — i — i — i — i — i — i — i — i — i —  0  A S O N D J F M A M J J A S O N D J F M 1977  Figure  1978  2a. Bottom w a t e r 1977 t o 1979.  10  a t Woodward I s l a n d  from  T  O N D J 1977'  Figure  temperature  1979  F M A M J  J A S O N D J  1978  FM 1979  2b. Bottom w a t e r s a l i n i t y a t Woodward I s l a n d from 1977 t o 1979. The t i d a l c h a n n e l i s a f r e s h w a t e r e n v i r o n m e n t d u r i n g t h e e a r l y summer.  27  s p r i n g  (Figure  3 a ) .  e a r l y  summer  and  midsummer. r e f e r t i d e  lower  one,  the  end  a t  of  4b,c,d) year:  females  u n t i l  throughout  showed  t h e  (Figure  suggested (1) an  e a r l y  June  and  August;  hatched  e a r l y  i n  o v e r w i n t e r i n g  hatched  maxima The  N.  a  t o  second  had  bred  g e n e r a t i o n  (W)  which  o f  t h e S2  w i t h  p o r t i o n  of  g e n e r a t i o n t h e S2  i n  hatched  g e n e r a t i o n  were  1977).  from  were  and  and  mid-  found  from  b r e e d i n g  was  August, of  a d u l t s  h a t c h e d breed  October;  c o n s i s t e d  of  maxima (Figure p e r  i n  l a t e  i n  l a t e  (S2)  which  and t h e  autumn, d i d  of and  g e n e r a t i o n s  g e n e r a t i o n  which  greater  c o n t a g i o u s l y  e a r l y  i n e a r l y  non-  t h e abundance  (S1) which  summer  were  ( E l l i o t t  three  mature  and  was  appearances  immatures,  g e n e r a t i o n  r a p i d l y  May,  t h e  (Anova,  c o n s i s t e n t l y  p e r i o d ,  s u c c e s s i v e  mercedis  summer  comparisons  A l t h o u g h  i n e a r l y  of  maxima  c o n t i n u o u s l y  month  by  a t low  minima  j u v e n i l e s  2  c o n s i d e r a b l y  summer  sampling  November.  August  o f f s p r i n g that  newly  j u v e n i l e s ,  (2)  my  25%  were  p o p u l a t i o n  of  t h e seven  grew  J u l y - e a r l y  t h e  were  p r e s e n t  4 a ) .  that  r a t i o s  measured  s p r i n g  a l l other  s c a l e  e a r l y  o f  The  i n  measurements  about  c h a n n e l s  t h e  900-l000'm~  were  only  were  pronounced  abundances  May-early  from  a t  r a p i d l y  d e n s i t y  and  1976).  b u t  t h e s p a t i a l  A p r i l  mid-October in  t h e  r i v e r  that  mid-October;  c o n t i n u o u s embryos  t e s t ) ,  i m p l i e d  b e a r i n g  t o  that  Variance-to-mean and  d i s t r i b u t e d  a l _ .  i n c r e a s e d  s t a b i l i z e d  u t i l i z e  d i s t i n g u i s h a b l e  s i g n i f i c a n t .  March  noted  c o u l d  e_t  S c h e f f e ' s  Egg  l e s s  i n t h e main  (Northcote  s t a t i s t i c a l l y  than  be  mysids  D e n s i t i e s  p<0.05,  or  l e v e l s  t o t h e s i d e c h a n n e l h a b i t a t  t h e  c h a n n e l .  more  I t should  only when  P o p u l a t i o n  n o t  (3)  an  j u v e n i l e t o g e t h e r mature  28  ~*  2000  c © a  10 ' — i  1  1  O N D J  1—t—i  1977  Figure  1—i  •—i  F M A M J J  1—i  1—i  A S O N  1  D J  1978  1—i  1  F M 1979  3a. The s e a s o n a l a b u n d a n c e o f N e o m y s i s m e r c e d i s a t Woodward I s l a n d b e t w e e n O c t o b e r 1977 a n d M a r c h 1979 V e r t i c a l l i n e s represent ± 1 standard e r r o r . The summer maxima a r e s i g n i f i c a n t l y d i f f e r e n t f r o m t h e w i n t e r - s p r i n g minima (p<0.05).  10  1  — • — i — i — i — i — i  O N D J 1977  Figure  1 — i — i — •  F M A M J J 1978  1 — i — • — i — i  A S O N D  1— •—i —  J F M 1979  3b. The b i o m a s s (± 1 SE) o f N e o m y s i s m e r c e d i s a t Woodward I s l a n d f r o m 1977 t o 1979 .  29 (a)  J  OHO  F  M  A M '  J J ' A ' S ' O N '  P ' J ' F  (b)  CD  E <D CO  cr co  O  N  D  J  F  M  A  M  J  J  A  8  0  N  D  J  F  U  300  O  N  D  J  F  U  A  U  J  J  A  S  O  N  D  ° - O JruA  M  J  J  ' A tO  N  J  0  F  M  Adult M i l * .  ao  o  N  o  j  r  M  A  M  J  J  A  S  O  N  O  J  F  1U7T  F i g u r e 4. The s e a s o n a l a b u n d a n c e o f f e m a l e a n d m a l e N e o m y s i s m e r c e d i s a t Woodward I s l a n d , 1977 t o 1979 . ( a ) eggs and e m b r y o s (b) j u v e n i l e s , ( c ) immatures, (d) a d u l t s . Note t h e d i f f e r e n t s c a l e s .  M  30  before  f a l l i n g  o v e r w i n t e r i n g A p r i l - M a y ,  g e n e r a t i o n  g i v i n g  The  and  which  breeding  t o  ( F i g u r e  which 5 ) .  ( R i c k l e f s  The  g e n e r a t i o n , d u r a t i o n  85 and  of  t h e  approximately  57  g e n e r a t i o n , The  210+  and  r e l a t i v e f l u c t u a t e d  i n  of  of  t h e  together  p r o p o r t i o n  of  age  a t  m o r t a l i t y  of  s u c c e s s i v e  p o p u l a t i o n  w i t h  t h e  t h e W  when  p r o d u c t i o n  females,  f o r t h e  S1  gave  as  t h e appearance  were  56+  g e n e r a t i o n ,  of t h e  embryos  as  f o r t h e  S2  g e n e r a t i o n . ( F i g u r e  days  j u v e n i l e s , v a r i o u s  r e l a t i v e l y  much  of  breeding  season,  w i t h  a d u l t  (±4.22)%.  of  The 5)  f o r t h e  as S2  g e n e r a t i o n .  were  t o t a l  43  which  p o p u l a t i o n  days  e s t i m a t e d  but  t h e  t h i s  o v e r w i n t e r i n g  stages S1  reproduced,  f o r  g e n e r a t i o n ,  f o r t h e W  s e a s o n a l l y  females  time  from  f o r t h e  f o r t h e  s u c c e s s i v e  which  g e n e r a t i o n  78.1  and  c l a s s e s  p r o p o r t i o n s  c o m p r i s i n g  development  s i z e  t h e  5)  j u v e n i l e s  by  through  days  of  by  season,  components  ( F i g u r e  n=l0)%  b l u r r e d  s i z e - s p e c i f i c  waned  (SE=±0.46,  somewhat  breeding  and  t h e  i n  (S1b) i n  f r e e - l i v i n g  185+  breed  peak  days  days  were  between  estimated  days  t o  The  d i s t i n g u i s h a b l e secondary  average t h e  i n A p r i l  r a t e s  s t r u c t u r e  small  but  was  i n  i n s p r i n g ,  b r e e d i n g .  g e n e r a t i o n .  t h e  changes  s i z e  moved  1973),  approximately  d u r i n g  i n i t i a t e d a  S1  t h e g e n e r a t i o n s  broad  small  next  o v e r l a p  by  c u r t a i l e d p r i m a r i l y  changes  t o  approximate  a d u l t s  of  t h e  temporal  c l u t c h  a  abundance  w i l l  The  was  second  by  l e d  g e n e r a t i o n s .  r i s e  t o  induced  m a t u r a t i o n ,  a  matured  r e p r o d u c t i o n  temperature  of  r i s e  i d e n t i t i e s  continuous  r a t e s  temperatures  immatures,  g e n e r a t i o n s constant  females  p o p u l a t i o n  waxed  throughout  comprising on  and  average,  3.2 and  31  6 0 - -  S1  q 4  0  "  82  w \  I /  w  82, S1  2 0 - -  7\. S1  f  Sib H  1  O N D 1977  1  1 -X n  rr  I I y  J F M A M J  i  J  1-  1978  ' v  v  •  H  1  1  A S O N D J  1  > h- H c  M 1  F M  1979  F i g u r e 5. R e l a t i v e p r o p o r t i o n s of j u v e n i l e s , immatures,and a d u l t Neomysis mercedis at Woodward I s l a n d between October 1977 and March 1979 . (o) a r e j u v e n i l e s , (•) are immatures, and (°) a r e a d u l t s . Generations are designated a s : (W) o v e r w i n t e r i n g , (S1) f i r s t summer , and (S2) second summer . The S1 generation shows a small secondary group ( S i b ) .  32  Peak Biomass  biomass  values  increased  generations  grew  and  t o  constant  a t  i n c r e a s e d  s l i g h t l y  generation  Body  winter  values  s i z e ,  d i e d  changes  i n  and  sex  a d u l t  mg  from  t o  which  t o a  2.3  2  t o  as  I t  3 b ) .  t h e S1  and  remained  throughout  then  f a i r l y  t h e  decreased  S2  w i n t e r ,  as  t h e  W  June.  i m p l i e d  that  t h e s i z e  m o r t a l i t y . f i e l d  mean  ( F i g u r e  6b)  2.9  The  10  about  f i r s t  and  temperature  h i s t o r y  females  that  a t  a t of  a d u l t  q u a n t i l e  mm  t o  d i f f e r e n c e s  cause  7a)  20°C  may  1978) s i n c e  n o t been  a t  20°C  This about  showed  6 c ) ,  from  a  a  which  r e d u c t i o n  s i z e - d i f f e r e n t i a l  changes  g e n e r a l l y  have  t h e  m a t u r i t y ,  from  The  6a)  females,  a t m a t u r i t y  (Anova,p<0.01).  from  ( F i g u r e  f o r these  mm.  egg  t h e a d u l t  r e s u l t e d  t h e s i z e  ( F i g u r e  o f  mm  rather  2.2  weight  f i r s t  2.0  (Figure i n  and l i f e  f e c u n d i t y ,  females  d r y  a t  s e v e r a l  t o about  percent  2.8  i n  c o n s i d e r a b l y  l e n g t h  t h e s i z e  t h e summer  m a t u r i t y ,  mean  (de March had  changes  decreased  uropod  regime;  temperatures l a b o r a t o r y  s i z e  between  i n t h e  proximate  females  by  s i z e  r e p r o d u c t i o n  temperature  i n c r e a s i n g  mm  d e c l i n e  from  The  males  t h e  The  t h e s e a s o n a l  a t  time  accompanied  approximates  change  w i l d  May  i n c l u d i n g  mg.  b e t t e r  reared  were  near  s i m i l a r  in  mg-m"  generation  r a t i o .  males  corresponded  the  d i e d .  s p r i n g ,  i n l a t e  (Figure  2  s u c c e s s i v e l y  and 100  t h e  a d u l t s  parameters  summer,  in  near i n  generations  h i s t o r y  5.4  decreased  m a t u r i t y  q-m"  0.6-1.0  S i z e  The  and  were  was of  l a b o r a t o r y  decreased  smaller  r e s u l t e d some  p r o b a b l y  e f f e c t from  i n d i v i d u a l s  c o n t i n u o u s l y  over  with seen p r i o r were t h e i r  33  3.5  T  Female  1  o  3.0  •• o  E 2.5-  j I *  a o  5  2.0--  1.5 I — i  ( — i 1-  H  1-  1  O N D J F M A M J J 1977  Figure  1 1 1 1 1 1 1  H  A S O N D J F M  1978  1979  6a. S e a s o n a l changes i n the mean s i z e ( ± 1 SE) of a d u l t female Neomysis m e r c e d i s a t Woodward I s l a n d , 1977 - 1979 . 3.5  T  Male E E  3  0  5 .1  2.5--  -j  M0  0  55  2.0  1.5  1 ^  1  H  1 1 1 1-  O N D J F M A M J 1977  •*  1  1  1  J A S O N D  1  1978  1  1  J F M  1  1979  F i g u r e 6b. The s e a s o n a l p a t t e r n of mean (+ 1 SE) s i z e of a d u l t male Neomysis m e r c e d i s a t Woodward I s l a n d . 3.5  X  3.0  2.5--  o  „ o  Z3 2.0--  1.5  1  h O N D J 1977  Figure  F M  A  M  J  J  1978  A S O N D J  F M 1979  6c. The s e a s o n a l p a t t e r n of the 10 p e r c e n t g u a n t i l e s i z e of a d u l t female Neomysis m e r c e d i s a t Woodward Island .  34  3.0  E $ £  2.5  a  c a _i o a o  2.0  w  1.5 5  10  15  20  25  Temperature (C)  Figure  7a. The s i z e a t m a t u r i t y (± 1 SE) o f r e a r e d male ( o ) and f e m a l e (•) Neomysis m e r c e d i s a t d i f f e r e n t temperatures .  3.0  E E  2.5  at ca & o  2.0  3  1.5 0  5  10  15  20  Temperature (C)  Figure  7b. , The e f f e c t s o f p r i o r t e m p e r a t u r e h i s t o r y on t h e s i z e a t m a t u r i t y o f f e m a l e N. m e r c e d i s a t Woodward Island . The d a t a f o r m a t i m e s e r i e s g o i n g c l o c k w i s e f r o m O c t o b e r 1977 ( l o w e r l e f t ) t o M a r c h 1979. The s i z e a t m a t u r i t y o f f e m a l e s w h i c h m a t u r e a t a g i v e n ambient t e m p e r a t u r e v a r i e s d e p e n d i n g on t h e d i r e c t i o n o f temperature change.  35  l i f e s p a n . of  newly  of  mature  the  The  maturing  time  of  was  sampling w i t h  s i z e  than  regimes.  The  and  food  t h e  accounted  f o r by  same  was  t h e  r i s i n g r e s u l t a  o f  food  t h e s i g n i f i c a n t  h y s t e r e s i s  a t of  temperature m a t u r i t y  a t  temperature  e f f e c t s of  of  food  s i z e  a g a i n s t  f u r t h e r  i n c r e a s e  e x p l a i n e d  temperature  Animals  ( a t t h e time  f a l l i n g  d i d n o t  a t  matured  a t  t h e  t h e v a r i a n c e  s i z e  change.  s i z e  r e g r e s s i o n  a v a i l a b i l i t y ,  d e c i l e  f a l l i n g  and from  s i z e  marked  temperature  e x p e r i e n c e d  I n  a  t h e  temperature  temperatures  between  n o t  t h e f i r s t  temperature  ambient  d u r i n g  1 7 a ) .  o f  r i s i n g  which  p r o p o r t i o n  frequency  c a r r i e d  by  changed mean a  yg  mode  beyond  e f f e c t  was  t h e  l i t t l e common  d u r i n g  a t  1978.  25-30 The  egg t h e  summer  modal  o v e r l a p s i z e  nq  egg  o f  t h e  mean  i n t h e Woodward  i n t h e s p r i n g  8 a ) .  eggs,  females  d u r i n g  weights  (Figure  most  occur  i n d i v i d u a l  major  l a r g e r There  d i s t r i b u t i o n s  s e a s o n a l l y  egg  w i t h  the  o f  There  on  that  ( p < 0 . 0 l ) .  Size  The  45  7b) .  d i r e c t i o n  d i d  (Figure  (p=0.08)  Egg  t h e ambient  d i f f e r e n c e s  p r o b a b l y  temperature  a g a i n s t  those  regimes  a v a i l a b i l i t y  p l o t t e d  t h e  temperatures  h i s t o r y  when  (Figure  s i m i l a r  temperature e v i d e n t  regimes  f o r  sampling)  p r i o r was  t h e  e x p e r i e n c e d  l a r g e r  of  animals  females  a s s o c i a t e d which  e f f e c t  The  and  a  much  s m a l l e r  being  35-40  and  i n t h e s p r i n g  b r e e d i n g  summer.  The  s p r i n g  Mg  summer  and  eggs  p o p u l a t i o n  was mode  h a d , on  i n t h e s p r i n g  o f  d i s t r i b u t i o n  g e n e r a t i o n  g e n e r a t i o n s s i z e  I s l a n d  frequency  b r e e d i n g  s i z e  b i m o d a l , a t  40-  average,  much  ( F i g u r e  8 b ) .  d i s t r i b u t i o n s ;  a n i m a l s  summer  o f  egg  d i d  n o t  weight  -  36 50  (a) 1978  SPRING  40 30 20 10 +  0 10  SO  20  30  40  SO  60  (b)  T  1878  SUMMER  40 30  u c © 3  cr  20410 0 10  c 0) u  O.  4=20  30  40  60  80  60  (c) 1078  SPRING  404 30 20 10 +  0 10  20  30  —I— 40  —I  60  60-  60  (d) SPRING  40  1880  30  2010  0 10  20  30  40  60  60  E g g W e i g h t (ug)  Figure  8. The f r e q u e n c y d i s t r i b u t i o n s o f mean egg w e i g h t s f o r Neomysis m e r c e d i s a t Woodward I s l a n d , 1978-1980 . (a) s p r i n g 1978 (n=39), (b) summer 1978 (n=26), (c) s p r i n g 1979 (n=13), a n d (d) s p r i n g 1980 (n=46).  37  frequency d i s t r i b u t i o n s d i f f e r ' s i g n i f i c a n t l y Smirnov 2-sample t e s t ) .  the  The females appeared to be d i v i d e d  (egg weights < 3 5 Mg) and l a r g e  small  former  predominant  in  the  l a t t e r present i n the summer. small  and  large  (±0.95,n=29)  size  forms  average  26.1  Mg r e s p e c t i v e l y .  should  egg  size  egg weight, was  was probably c o r r e l a t e d with weights  of  hatchlings  mean egg weights  (14-48  Mg).  (15-58  newly  11.4  egg  f o r the and  (SE=±0.51,n=38)  Within-clutch  i n the dry weight of  reflect  with  e a r l y s p r i n g breeders and the  The  were  into  (> 3 5 Mg) egg types,  variation  was not examined but the average w i t h i n - c l u t c h  of v a r i a t i o n  Kolmogorov  (p<0.01,  hatched  Mg)  as  in  coefficient  young,  which  the  range  was s i m i l a r  of  dry  to the range of  The frequency d i s t r i b u t i o n s of egg  weights seen i n the s p r i n g s of 1 9 7 9 and 1 9 8 0 (Figure 8 c , d ) significantly sample  different  test).  distributions  In  from that of s p r i n g  both  were  1 9 7 9 and  unimodal  1980  and  mean egg weight  indistinguishable spring  1980  mean  in spring  1979  of  (39.8  33.5  Mg  (±0.84,  Mg  for  n=46)  egg  than were ±1.61,  were KS  (p<0.05,  the  weights  from the l a r g e egg mean of  1978  heavier  d i s t r i b u t i o n a l t h o u g h the ranges of egg The  egg  S i z e at h a t c h i n g  (±0.94)%.  size  42.5  2-  weight the 1 9 7 8 similar. n=l3)  1 9 7 8 while  was the  was i n t e r m e d i a t e i n  value. Egg s i z e was except  the  1978  independent  female  size  for  a l l cases  small egg type where there was a weak i n v e r s e  r e l a t i o n s h i p which accounted variance.  of  for  only  15%  of  the  egg  size  38  Fecundi ty  The  brood  increased during  s i z e  e x p o n e n t i a l l y 1978  females  (p<0.05,Ancova) and  9 b ) .  against  (the  i n  The  1.  with  t h e i r  48-50  %  of  the  the  <  35  p r o d u c i n g  the  c l a s s e s  of  mean the  s i z e  of  the  and  s m a l l  large  i s  given  i n  of  I  embryos)  mother, eggs  r e l a t i o n s  r e g r e s s i o n  . 547 . 562 .2 9 4 . 801 . 1 25 - o . 903 0. 0863 - 4 . 99 0. 737 -0 -0 -1 -0 -0  Table  1.  but  d i f f e r e d  (Figures  log(number  egg  t o t a l  (p>0.05),  i n  of  weights  dry  weight  f o r of  SE)  .79 .73 .80 .94 .61 .96 .89 .65 .994  (0 (0 (0 (0 (0  .018) .016) .21 ) .57) .48) .18) .41 ) .62) .005)  egg  (1 (0 (1 (0  number.  females 1.56  eggs.  females  (1  of  S i z e  9a eggs)  accounted  The  c l o s e l y l a r g e the  0. 0. 0. 0. 0. 0. 0. 0. 0.  were  c a r r y i n g as  r  many  r a t i o  eggs of  c l u t c h  s m a l l on  n  99 99 62 50 49 27 48 53 99  38 30 1 5 28 1 0 236  the  with  as  the  slopes  a  mean  s i m i l a r  s i z e d  egg t o  eggs.  the  1 95 22 1 67  s t a t i s t i c a l l y  eggs  corresponded  and  2  A l t h o u g h  r e l a t i o n s  about  l a r g e r  b 2 2 2 4 3 4 2 6 0  v a r i a t i o n  jug h a d  females  the  i n c r e a s i n g  s i z e - f e c u n d i t y  weight  two  stage  a  i n d i s t i n g u i s h a b l e dry  or  Summary of s i z e dependent r e l a t i o n s of the form log(y) = a + b l o g ( u r o p o d l e n g t h i n mm) for female Neomysis mercedis from Woodward I s l a n d , 1978.  t o t a l weight (mg) body weight (mg) c l u t c h weight (mg) egg number (<35ug) 11 ,111 embryos IV,V embryos egg number (>35ug) sperm weight (ug) body l e n g t h (mm)  of  eggs  s i z e - f e c u n d i t y  s i z e )  y  for  of  c a r r y i n g  f u n c t i o n a l  l o g ( f e m a l e  Table  number  s i z e  numbers  the The of  r a t i o  f o r of  dependence the  mother  39  100T <35  ug  (0  CD CD HI  © E z  10--  Uropod Length (mm) F i g u r e  9 a . s i z e  The r e l a t i o n s h i p between brood s i z e and for females p r o d u c i n g " s m a l l " eggs d u r i n g  female 1978.  100-r >35  ug  m  CD CD UJ  © XI  E  10-1  1  1  2  3  1  4  1  5  Uropod Length (mm) F i g u r e  9b. s i z e  The r e l a t i o n s h i p between brood s i z e and for females p r o d u c i n g " l a r g e " eggs d u r i n g  female 1978.  40  (Figure l a r g e Of  10a)  eggs.  t h e  was C l u t c h  female  produced  males  a n ima1  (Fi g u r e  c l u t c h  weight  of  IV  and  V)  females  embyros  l a t e  d i f f e r  from  in  for  s p r i n g N.  of  1980  -  female  were  -  s i z e  1.53  I I I  stage  of  of  t h e  of  t h e  0.005  -  t h e  (stage stage  i m p l i e d  0.009  d a y " ' d i d not  (p>0.05).  c a r r i e d  an  The  by  females  than  temporal  changes  female  s i z e  r a t h e r -  of  e a r l i e r  I I I embryos  embryos  f o r that  o l d  which  embryos  number  s i z e  f o r which  s m a l l  eggs  r e l a t i o n  t h e m o r t a l i t y  than  i n s p r i n g  that  (Ancova,p>0.05).  t h e  c o n s t a n t , those  seen  from  v a r i a t i o n  A l t h o u g h  remained h e a v i e r  r e l a t i o n s  i n d i s t i n g u i s h a b l e  y e a r - t o - y e a r  r e l a t i o n s .  times  s i z e  was  p>0.05).  c a r r y i n g  r e l a t i o n s  stage  samples  sperm  slopes  of  f e m a l e s ,  and  t h e  of  r e l a t i o n s  t h e  t h e number  stage  m o r t a l i t y  s i z e  suggested  t h e number  of  over  s i g n i f i c a n t  about  egg  t h e  1-2%  s i z e  A l t h o u g h  of  l a t e  t h e  about  f o r embryos  egg  however,  weight  of  w i t h  9a,11a,11b)  s i z e d  and  with  and  s i z e .  75%  t h e  number  mercedis  female  eggs  s m a l l  weight  number-female  s i n c e  (Ancova,  egg  rate  d r y  only  same  about  Numbers  i n v a r i a n t  c a l c u l a t e d  and  s i m i l a r  m a r s u p i a l  remained  was  m o r t a l i t y .  by  r a t e s  t h e  ( F i g u r e s  only  w i t h  e x p o n e n t i a l l y  (p>0.05,Ancova),  m o r t a l i t y  those  o v u l a t i o n  The  s t a g e s  i n t h e number  r e f l e c t e d  t h e  was  s p r i n g .  r e d u c t i o n  1 ) , but of  f o r females  e x p o n e n t i a l l y  t h e embryo  d i f f e r  c a r r i e d  i n s t a n t a n e o u s in  of  embryos  i n c r e a s e d S i m i l a r l y ,  p r e - h a t c h i n g  d i d not  (p>0.05)  i n c r e a s e d  embryonic  was  l i n e s  1 ) .  10b, Table  Comparison  there  weight  (Table  by  s u c c e s s i v e  i d e n t i c a l  of  1979  e q u i v a l e n t  of  i n  There  i n t h e c l u t c h  s l o p e s t h e  seen  1979  t h e  1978 was,  weight c l u t c h  broods  averaged  s i z e d  females  41  0.2  Uropod Length (mm) Figure  10a. The r e l a t i o n s h i p b e t w e e n . t h e c l u t c h w e i g h t a n d f e m a l e s i z e f o r N e o m y s i s m e r c e d i s a t Woodward I s l a n d . 1978 .  Uropod Length (mm) Figure  10b. The r e l a t i o n s h i p between sperm w e i g h t a n d male s i z e f o r N e o m y s i s m e r c e d i s a t Woodward I s l a n d .  42  100  T  Stage 2,3  (0  o> ut 0)  E Z  10"  5+  2  3  Uropod Length (mm) Figure  11a. The d e p e n d e n c e o f t h e number o f s t a g e I I a n d I I I embryos on f e m a l e s i z e f o r f e m a l e s c a r r y i n g " s m a l l " embryos, 1978.  Figure  11b. The d e p e n d e n c e o f t h e number o f s t a g e s t a g e V embryos on f e m a l e s i z e , 1978.  IV and  43  in  1978  while  t h e  1978  than the  t h e  p r e d o m i n a n t l y  of  eggs  few  summer  a  breeding small  weight  a  breeding same who  l a r g e  numbers  of  -  without  a f f e c t i n g  r e l a t e d  measures  R a t i o  The about  in  while W  of  females  as  l a r g e  small  l a r g e  but  t h e same  upward t h e  output  who  t o t h e  l i n e .  eggs.  female  which  1980  s p r i n g  produced  t h e  females  b u t  t h e  c l u t c h  1978  a n i m a l s  V a r i a t i o n  and  The  c l u t c h  s h i f t e d  r e l a t i v e  small  t o t a l  g e n e r a t i o n  which  of  females  and  females  s p r i n g  eggs  o f  1979  l a r g e  1978  l a r g e r  i n  s i z e -  c o n d i t i o n  a r e  2.  r a t i o  (Figure a l s o  matured  matured  increased  of b u t  1 2 ) .  i n  d e c l i n e d  s t e a d i l y  percentage  died  s p r i n g  and  a f t e r  t h e  reached  of  5 a ) , t o  t h e low w i n t e r  t h e  q u i c k l y ,  p o p u l a t i o n  (Figure  females a t  t h e whole  The  d e c r e a s e d  t h e mature  females  g e n e r a t i o n  of  of  of  t o  c o n s i s t e d  c l u t c h e s  c o n s i s t e d  t h e  t h e summer  t h e w i n t e r  no  l a r g e  The  c l o s e l y  g e n e r a t i o n  c l u t c h e s  eggs  h e a v i e r  F e r t i l i t y  during  w i n t e r  producing  r e p r o d u c t i v e  i n Table  and  as  times  years.  breeding  b a s i s .  t h e slope  t h e p o p u l a t i o n  the  o f  1.27  correspond  between  p r o d u c i n g  r e l a t i o n  malerfemale  one  d u r i n g  young  s i z e  summarized  weights  c o n s i s t e d  s i g n i f i c a n t l y  weight  Sex  females  about  d i f f e r e n c e s  females  s i z e - a d j u s t e d  numbers  averaged  1978, t h e s p r i n g  g e n e r a t i o n s  l a i d  egg  g e n e r a t i o n s  produced on  The  i n mean  during  with  broods  c l u t c h e s .  d i f f e r e n c e s Thus,  1980  76%  f l u c t u a t e d t o  0.2-0.3  adult  females  <  breeding  1%,  during  i n  October  t e m p e r a t u r e s . percentage by  l a t e  o f  A p r i l .  As  t h e  a d u l t This  4.4  Table  2.  Homogeneous g r o u p i n g s of of r e p r o d u c t i v e output an Bracketted groups do not the 0.05 p r o b a b i l i t y l e v e have been log-transformed 1 = 1978 s m a l l . e g g t y p e , 3 = s p r i n g 1979, 4 = s p r i  s i z e - a d j u s t e d measures d female c o n d i t i o n . d i f f e r s i g n i f i c a n t l y a t l (Scheffe t e s t ) . V a r i a b l e s t o homogenize v a r i a n c e s . 2 = 1 9 7 8 l a r g e egg type, n g 1980.  v a r l a b l e egg  groupings  weight  1  <  4  <  ( 2 , 3 )  s i z e - a d j u s t e d : a)  f e c u n d i t y  b)  c l u t c h  c)  body  d)  t o t a l  r e f l e c t e d time. the  s p r i n g  l a t e  that  from  about  zero  10  per  A l t h o u g h  a d u l t  females  <  <  3  ( 1 , 3 , 4 )  ( 1 , 4 )  then  range  from  d e c l i n e d  that  r a p i d l y  females  2-5%  a t  d i e d .  as The  f o r t h e balance  of  3.2%. t h e  a d u l t 80%  r a p i d l y  1 3 ) .  t o  The  female  t o  females t h e W  s t a b i l i z e  were  by  female  i n  produced  J u l y  t h e  i n t h e summer by  g r a v i d  matured as  s i z e W  these i n  s i z e  of  p r o p o r t i o n per  a d u l t  generation  (Figure  about  i n  60-70%  i n t h e  brood  t h e  were  between  r e d u c t i o n  t h e average  throughout  broods  40%  t h e decrease  a d u l t  which  generation  about  s e a s o n a l  w i t h  p e r  as t o  again  lower  eggs  m u l t i p l e  4  4)  p o p u l a t i o n  i n t h e  combined  30  t h e  generation  t o about  b r e e d i n g  i n  t h e W  increased  about  <  <  and  of  (Figure  males  a d u l t  averaged  females  were  female  hatched  and  summer  of  of  d e c l i n e d  d i e d  b r e e d i n g  to  from  s p r i n g ,  females  numbers  percentage  i n c r e a s e d the  2  s t a b i l i z e d and  ( 1 , 3,  ( 1 , 2 , 4 )  p r o p o r t i o n  summer, The  low  <  ( 1 , 2 )  weight  brood  percentage the  weight  weight  t h e  The  2  21%  1 4 ) . of  t h e  O N D J F M A M J 1977 Figure  12. males  1.0  J  A S  O.N  D J F M  1978  1979  The s e a s o n a l p a t t e r n : f e m a l e s a t Woodward  of the r a t i o of I s l a n d , 1977 t o  ON  J A S  1977.  T  0.8 a  5  0.6  o  CL O °- 0.4  0.2  1977 Figure  13. female  50  J F M A M J  ON  D J F M  1978  1979  The s e a s o n a l p a t t e r n of t h e p r o p o r t i o n Neomys i s m e r c e d i s t h a t a r e g r a v i d .  of a d u l t  T  O N 1977 Figure  D  D J F M A M J J  A S O N D  1978  14. The s e a s o n a l p a t t e r n a t Woodward a v e r a g e number o f eggs p e r a d u l t f e m a l e m e r c e d i s , 1977 - 1979 .  J F M 1979 I s l a n d of Neomysis  46  females rates made  reared  i t  June,  w e l l  suggested produced  3.  females  a  the  small  of  (chapter  females  i n  produced  2 ) , the  the  m o r t a l i t y  n a t u r a l  p o p u l a t i o n  a  second  s u c c e s s f u l l y  brooded  l a r g e  f i r s t  g r a v i d  d e c i l e  p r o p o r t i o n  (<  more  females  a d u l t  10%)  c l u t c h ,  s i z e  of  than  two  u n t i l  l a t e  had  d e c r e a s e d ,  W  generation  three  generations  the  are  c h a r a c t e r i s t i c s  summarized  i n  of  Table  the  3.  Summary of the r e p r o d u c t i v e c h a r a c t e r i s t i c s the three generations of Neomysis mercedis Woodward I s l a n d d u r i n g 1978.  parameter s i z e at b r mean egg s c l u t c h wei average # percentage number of generation p o p u l a t i o n  and  c l u t c h e s .  r e p r o d u c t i v e  m e r c e d i s  many,  p e r s i s t e n c e  m u l t i p l e  The  Table  any  a f t e r  t h a t  a d u l t  that  that The  l a b o r a t o r y  for  u n l i k e l y  c l u t c h e s .  N.  the  c a l c u l a t e d  improbable  of  i n  w  e e d i n g (mg) i z e l a i d (ug) ght / body weight eggs / brood g r a v i d broods time (days) 2 d e n s i t y (#/m )  S2  SI  5.44 26. 1 0.19 25 >80 1 2 2 10 + 40  of at  2.25 42.5 0.19 9 <60 1 2 85 + 900  2.89 42. 5 0.19 1 2 70 1 56 + 1 400  Demography  I n s t a n t a n e o u s v a r i a t i o n  over  rates  h i g h e s t  were  generation  per  the i n  hatched.  c a p i t a 1978 the  b i r t h  b r e e d i n g l a t e  s p r i n g  Maximum  r a t e s  r a t e s  showed  c o n s i d e r a b l e  season  (Figure  as  o f f s p r i n g  of  the  about  0.27  15).  B i r t h  of day"  the 1  W were  47  0.5T  5 0.4-©  M  J  J  A  S  O  1978 Figure  15. P e r c a p i t a i n s t a n t a n e o u s b i r t h r a t e s f o r Neomysis m e r c e d i s a t Woodward I s l a n d , 1978 . Vertical lines r e p r e s e n t 95% d i s t r i b u t i o n l i m i t s f r o m r e p e a t e d r e e s t i m a t i o n of the b i r t h r a t e s .  0.001 -  1  20  1  1  1 — I — l i l l  100  1  1  1  1 — I — l i l l  1  1000  Population Density (^/square meter) Figure  16. Dependence o f p e r c a p i t a i n s t a n t a n e o u s b i r t h r a t e s o f N e o m y s i s m e r c e d i s a t Woodward I s l a n d on population density .  48  found low  i n  l a t e  May.  The  values  (0.01  s i z e  c l a s s e s  three l e n g t h  c l a s s  T h e r e a f t e r ,  made  b i r t h  r a t e .  p o p u l a t i o n  d e n s i t y  suggested  that  c o m p e t i t i o n  for  b i r t h  r a p i d l y Egg  to  p r o d u c t i o n ,  female  ( F i g u r e  n=13)  w i t h  p o s i t i v e l y p<0.05,  C o r r e l a t i v e  was  i n t e r c o r r e l a t i o n s  i s  at  l e a s t  d e t e r m i n i n g  the  Instantaneous N.  mercedis  Because  the  t h i s  w i t h  v a r i e d  r a t e s  an  i n  s o r t  N.  r a t e s  mm  uropod  b i r t h  r a t e .  animals,  c l a s s e s  the  (1.8-2.8  to  the  mm)  o v e r a l l  v a r i a t i o n  p<0.0l,  peaked  number  determinant  of  weak  the  B i r t h  and  summer. per  a d u l t p<0.05,  r a t e s  crop  were  (r=0.75,  supply:demand  r a t i o .  p o t e n t i a l l y  b i a s e d  v a r i a b l e s .  N e v e r t h e l e s s ,  there  food  p l a y  r a t e s  l e v e l s at  f o r  a  Woodward  s p e c i f i c  throughout were  and  food  s p r i n g  eggs  s t a n d i n g food  the  (r=0.57,  r a t i o .  the  as  l a t e  of  c o r r e l a t e d  i s  as  throughout  mean  which such  such  i n  w i t h  n=12)  p r o c e s s ,  important  mercedis  c o n s i d e r a b l y  t o t a l  a v a i l a b i l i t y  w i t h  m o r t a l i t y  m o r t a l i t y  was  the  t h a t  A l t h o u g h  s m a l l e r  =0.74,  values  other  summer.  i n v e r s e  meiofauna  not  suggestion  b i r t h  the  two  supply:demand  although  by  2  17a)  as  w i t h  of  r  food  lower  constant  mid-October.  p o s i t i v e l y  food  evidence  to  s t r o n g  ( F i g u r e  c o r r e l a t e d  n=12)  of  measured  the  of  rather  2.8-3.5  density-dependent  much  14),  the  the  83%  to  to  c o n t r i b u t i o n s  16;  Measures  d e c l i n e d  a  r e s o u r c e s ,  r a t i o  -  a f t e r  ( F i g u r e some  r a t e s .  supply:demand  equal  showed  food  60  June  s h i f t e d  ceased  f e l l  throughout  narrowed  approximately  r a t e s  then  l a t e  f o r  range  B i r t h  the  u n t i l  r e p r o d u c t i o n  Breeding  r a t e  day"')  bred  s i z e  which  0.03  accounted  as  reproducing  -  b i r t h  time  estimated  major  r o l e  i n  I s l a n d .  s i z e  c l a s s e s  ( F i g u r e using  of  I8a-g). the  Lynch  49  F  M  A  M  J  J  A  S  O  N  D  1978  Figure  J 1979  17a. Food r e s o u r c e supply:demand m e r c e d i s a t Woodward I s l a n d .  index  f o r Neomysis  20 -r-0.57 16  ••  12  •  CO  E ©  li-  ra  TJ <  O CL  8 ••  in  O) cn at  4 •  O  10  20  30  40  50  Relative Food Availability (Supply:Demand) Figure  17b. C o r r e l a t i o n between egg p r o d u c t i o n ( m e a s u r e d a s the a v e r a g e number o f e g g s p e r a d u l t f e m a l e , a n d f o o d availability.  50 (a) Class 1  O.4..  >» CO  TJ  0.2  CO  CC >> 75  O  2  -0.2 ••  -0.4  J  1  O  1  N 1977  0.3  J  1  1  1  F  M  A  1  1  M  J  1  l  J 1978  1  A  l_: r _ i  S  O  i.  1  N  D  i  J  F  i  M  1979  (b) Class 2  T  1977  Figure  1  D  1978  1979  18. Seasonal v a r i a t i o n in instantaneous death rates (and 95% d i s t r i b u t i o n l i m i t s ) of N e o m y s i s m e r c e d i s a t Woodward I s l a n d , 1977-1979 . V e r t i c a l l i n e s represent t h e 95% d i s t r i b u t i o n l i m i t s from r e p e a t e d r e - e s t i m a t i o n of t h e m o r t a l i t y r a t e s . (a) = c l a s s 1 (0.3-0.8 mm u r o p o d l e n g t h ) , (b) = c l a s s 2 (0.8-1.3 mm),  (c) Class 3  1979  1978  1977  (d) Class 4  O  N  D  J  F  M  A  M  J  1977  J  A  S  O  N  D  J  1978  F  M  1979  (e)  Class 5  O  N 1977  Figure  D  J  F  M  A  M  J  J 1978  A  S  O  N  D  J  F  M  1979  18. Seasonal v a r i a t i o n i n instantaneous death rates (and 95% d i s t r i b u t i o n l i m i t s ) Neomysis m e r c e d i s a t Woodward I s l a n d , 1 9 7 7 - 1 9 7 9 . V e r t i c a l lines represent the 95% d i s t r i b u t i o n l i m i t s from r e p e a t e d r e - e s t i m a t i o n of t h e m o r t a l i t y r a t e s . ( c ) = c l a s s 3 ( 1 . 3 - 1 . 8 mm), ( d ) = c l a s s 4 ( 1 . 8 - 2 . 3 mm), ( e ) = c l a s s 5 ( 2 . 3 - 2 . 8 mm),  52  -0.2 J  1 O  1  1  D  J  N  1  1 F  1  M  A  1  1  M  J  1977  -0.2  J  1 O  1 D  1977  F i g u r e  18. Se ( a n d 95% Woodward (g) = c l a s s  1 J  1 A  1  S  1  O  N  1  1——I  D  J  J  1  1 F  1 M  1 A  M  1  1  J  1  1979  1 J  1978  1 F M  1978  1 N  1  1  1  1  1  1  A  S  O  N  D  1 J  1 F  1 M  1979  asonal v a r i a t i o n i n i n s t a n t a n e o u s death r a t e s d i s t r i b u t i o n l i m i t s ) Neomysis mercedis a t I s l a n d , 1977-1979 . ( f ) = c l a s s 6 (2.8-3.3 mm), 7 (3.3-3.8 mm)  53  a l g o r i t h m , t r u e  i t  values  m o r t a l i t y  between  : r a t e s of  s i z e  the  l i k e l y  (see  magnitudes  of  i s  Appendix are  the  r a t e s ,  c l a s s e s ,  For  the  (3)  50%  l a r g e s t  c o n f i d e n c e  about  l i m i t s  encompass  the  suggested  in  e s t i m a t e s  a b s o l u t e  magnitude  r e l a t i v e (Lynch  rates  from  A3).  d i f f e r e n t  e s t i m a t i o n c o u l d  c l a s s  to  would of  of  be about  the  magnitude  the  p o p u l a t i o n  u n c e r t a i n t y  i n  N e v e r t h e l e s s ,  c l a s s e s  95%  g e n e r a l l y  the  i n  r a t e s .  s i z e  s t r u c t u r e  However,  were  cause  m o r t a l i t y  m o r t a l i t y  values  r a t e s  b i a s  major  of  the  should  be  the the  c o r r e c t  1983).  The c l a s s  the  and  true  . (1)  the  s i z e  U n c e r t a i n t i e s  a  the  A2  of  t r u e  s m a l l e s t  m o r t a l i t y  3.  change  the  the  s i z e - f r e q u e n c y  data,  the  i f  of  which  upon  d u r a t i o n  T a b l e s  the  were  of  for  to  depends rate  the  underestimate  degree  i n i t i a l  values  of  the  I s l a n d  (see  Appendix  d e n s i t y -  The  (4)  30%  on  true  3 ) .  the  Woodward  by  the  s l i g h t l y  (2)  and  u n d e r e s t i m a t e d for  they  u n d e r e s t i m a t e d  p o p u l a t i o n ,  i n t e r v a l .  that  c o n s i s t e n t l y 1  (1)  subject s m a l l e s t  animals  during  i n a c c u r a c i e s to  l a r g e  for  u n i f o r m i t i e s  i n  algorithm)  are  l a t e  the  the  a d u l t  for  2 ) ,  1984), egg  or age  m o r t a l i t y  u n l i k e l y  to  (3)  may  e s t i m a t e s  from  from  account  for  (which  of  for  e f f e c t s on  d i e l  the  o t h e r  p e r i o d  were the of  expected  temperature Non-  than  i n c o r p o r a t e d the  for  a r i s e n  immigration.  d i s t r i b u t i o n i s  the  r a t e s  e f f e c t s  (which  have  s e l e c t i v i t y  growth  the  e s t i m a t e d  p e r i o d  gear  (2) or  from  r a t e s  summer  d e n s i t y  hatching  example,  Meyers  from  i n  the  f l u c t u a t i o n s ,  r e s u l t i n g  the  Appendix  of  (as,  m o r t a l i t y  adjustments  a n i m a l s ,  u n d e r e s t i m a t e s d e n s i t i e s  negative  of  i n  those the  negative  54  m o r t a l i t y  e s t i m a t e s  i n c r e a s e not  i n  evident In  Newly  to  l a t e  l e v e l s death  r a t e  June  of  v a r i a t i o n ,  2  r e l a t i v e l y s l i g h t l y l a t e r  i n  i n c r e a s e d  day"  c l a s s  constant  1  The  f o r and  which Death  h i g h  a  continuous  p e r i o d ,  which  f l u c t u a t i o n s  the 18a)  l a r g e r showed  born  i s  rose  at of  at  low, the  the  the  l a r g e s t the  -  0.42  the  r e l a t i v e l y  onset  i n  (0.18  through  breeding  were  c l a s s e s .  e a r l y  m o r t a l i t i e s  c o n s i d e r a b l y  remained  animals  f o r  Animals  remainder  a l l  showed  the  magnitude  l a r g e r  March  and  May.  l a r g e s t from  2,  day"  1  l a t e  constant  season.  The  winter  but  of  was r a t e s  day"  were  1  c l a s s  the  and  somewhat  r a t e s  and  g e n e r a l l y  then  m o r t a l i t i e s  c l a s s  3,  were  present  were  d e c l i n e d  occurred  Death  showed  and  r a t e s  d e c l i n e d were  0.09  day"  about 1  f o r  5.  d i f f e r e n t low  winter  seasonal v a r i a t i o n  M o r t a l i t y  peak  f o r  of  seasonal  September  c l a s s e s  They  q u i t e  to  p a t t e r n  d e c l i n e  summer  s i z e  p e r i o d .  of  c l a s s e s .  Late  for  s i m i l a r  d u r i n g The  mid-May  0.12  a  a n i m a l s .  values  l a r g e s t  v a r i a t i o n  the  seasonal  F i g u r e  very  low  c l a s s  s p r i n g  of  r a t e s .  and  v a l u e s .  to  1,  at  two  0.17  two  c l a s s e s .  1  the  w i n t e r  4,  winter  i n  the  over  than  d e c l i n e d  the  5  s t e a d i l y  low,  death  w i t h  between  r e q u i r e  w i n t e r .  -  but  d e c r e a s i n g  ( c l a s s  p e r i o d  the  C l a s s e s  c l a s s e s  r a t e s  c l a s s  over  p r o d u c t i o n  experienced  throughout  d e c l i n e d  0.20  s i z e  in  M o r t a l i t y  would  magnitudes  mysids  season  d a y " ' ) .  egg  the  v a r i a t i o n  t h i s  14).  s m a l l e r  hatched  breeding  of  ( F i g u r e  f o r  seasonal  to  r a t e  g e n e r a l ,  g r e a t e r  May  the  s i n c e  a  p a t t e r n  from  q u i t e  the  only of  i n  temporal  i n t e r m e d i a t e  constant  u n t i l  the  May  s i z e when  55  they  increased  g r e a t l y  w i n t e r  l e v e l s  in  June  l a t e  u n t i l  m o r t a l i t y p e r i o d , death than  when r a t e s  those  m o r t a l i t y and  of  of  g e n e r a l l y  l a r g e r t o  intermediate  in  s i z e - s p e c i f i c  two  rather  the  j u v e n i l e s For the  were t h e  range  i n c r e a s i n g  body  o c c u r r e d  (Figure  a g a i n s t c l a s s e s Am).  r a t e s l a r g e r  would The  p o s i t i v e l y  be  g e n e r a t i o n newly  The  rates  when  those  rates  body  s i z e s  during  over  May  i n c r e a s i n g  by  Am  with  N.  increase  p e r  day  ( s i n c e rate  t h e average  when  s u r v i v a l  with  hatched 1 9 ) . matured,  -  with  breeding  i n s t a n t a n e o u s  of  Am)  s e l e c t i o n t h e  l a r g e r  f o r  small  i n c r e a s i n g  ambient  during  increased  i m p l i e d  S2-S,(1  animals  newly  mercedis  as  s p r i n g  (2)  i n  s i z e  f o r  v a r i a t i o n  (Figure  October,  body  i n m o r t a l i t y  of  were  l i t t l e  hatched  animals  which  t o  r a t e s  t h e  and  r a t e s  l a r g e s t  summarized  during newly  g r e a t e r  f o r t h e  g e n e r a l l y  The  were  s i z e - s p e c i f i c  be  a d u l t s ,  l a r g e r  r a t e s  20a,b).  The  of  t h e death of  t h e  temporal  (1)  and  b r e e d i n g ,  v a r i e d  t h e r e f o r e  regimes:  immatures  June  of  but  i n  e a r l y  t h e m o r t a l i t y  o v e r a l l  c a n  t h e death  reduced  c o r r e l a t e d  p o p u l a t i o n  -  animals  r a t e s  1 a n i m a l s ,  a n i m a l s .  a d u l t s .  increase  hatched  t h e summer  m o r t a l i t y  with  was  high  than  s i z e  t h e  v a r i a t i o n  A p r i l  with  p e r i o d  of  t h e  U-shaped,  l a r g e r  l e s s  above  t h e  l i t t l e  p a t t e r n  when  s i z e - s p e c i f i c  m o r t a l i t y  During  m o r t a l i t y  breeding  was  t h e  m o r t a l i t y  of  from  a n i m a l s ;  During  s i z e  d i s t i n c t  those  s i z e .  f o r t h e c l a s s  p e r i o d  summer  be  mysids.  the  exceeded  there  t h e s m a l l e s t ,  lowest  b r e e d i n g  d i s a p p e a r e d  o v e r w i n t e r i n g  tended  s m a l l e s t  w i n t e r  with  t h e  c o n s i d e r a b l y  18f and 1 8 g ) .  t h e  rates  remained  t h e c l a s s e s  (Figures  Throughout  and  water  s i z e  was  temperature  56  0.4  -r  m  CD  T3  Z  0.2  -  o 2  3  < - 0 . 2  --  - 0 . 4  --  "E > 3  Figure  19a. D i f f e r e n c e i n m o r t a l i t y r a t e s between n e o n a t e s ( c l a s s 1) and a d u l t ( c l a s s 4) a n i m a l s . Positive values i n d i c a t e t h a t j u v e n i l e m o r t a l i t y r a t e s e x c e e d t h o s e of adults.  0.4  -•  CO  J >A  >»  CO  Z  0.2  •-  - 0 . 2  ••  - 0 . 4  --  75 k»  o  < 1  'c  CO > 3  Figure  19b. D i f f e r e n c e i n m o r t a l i t y r a t e s between n e o n a t e s ( c l a s s 1) and a d u l t ( c l a s s 5) a n i m a l s . Positive values i n d i c a t e t h a t j u v e n i l e m o r t a l i t y r a t e s e x c e e d t h o s e of adults.  57  over  the  estimation  increase  in  P=0.10,  n=24  the  m o r t a l i t y for  ambient  r e l a t i v e adult  m o r t a l i t y r e l a t e d  to  v a r i a n c e  in  of  chinook  the  salmon  the  that rates  F i s h  to  n=13 c l a s s  4  be  for  to  a  6;  r=0.35,  5).  Thus,  p r e d i c t o r  f u r t h e r  the  of  the  i n c r e a s e s  i n  (Table  4  were  food  2  accounted  nor  f o r  and  for  by  the  p r e d a t o r  death  a l l  s i z e s  measures  1  mysids w i t h  s m o l t s . (74%)  for  the The  of  regression  the  food  r e s o u r c e s  of  immature  34%  of  of  food v a r i e d  83%  of  of the  However,  s i g n i f i c a n t c l a s s e s .  c o e f f i c i e n t s  in  the  abundance  model.  s i z e  of  d e n s i t y  were  other  r e g r e s s i o n  f l u c t u a t i o n s  by  d e n s i t i e s  rates  s t a n d a r d i z e d  for  c l a s s  most  i n v e r s e l y  mysids  and  accounted  were  percent  f r y  salmon  s i z e - s p e c i f i c  one  d i r e c t l y  mysid  s i m i l a r  c l a s s  -  and  e x p l a i n e d  of  F i f t y  a v a i l a b i l i t y  sockeye  the  of  rates  of  l e v e l s  of  4 ) .  for  rates  p r e d a t o r s  of  m o r t a l i t y  rates  a n i m a l s  models  on  The  suggested m o r t a l i t y  a n i m a l s .  P r e d a t i o n  N. 5)  that  M o r t a l i t y  e f f e c t  was  r e g r e s s i o n  l e v e l s  and  food  the  5  c l a s s e s  a g a i n s t  m o r t a l i t y  v a r i a n c e  magnitudes  between  s e l e c t i o n  of  food  with  p r e d i c t o r s  c l a s s  c o u l d  suggested  a v a i l a b i l i t y .  neither  from  temperature  l i n e a r  c l a s s  i n v e r s e l y  rates  p<0.05,  s i z e .  rates  of  (r=0.58,  increase  water  Stepwise  t o t a l  the  i n t e n s i t y  body  that  i n t e r v a l  as  mercedis  w e l l  importance v a r i e d  as of  was  the  preyed  shrimp  N.  c o n s i d e r a b l y ,  by  Crangon  mercedis both  upon  as  a  a  v a r i e t y  f r a n c i s c o r u m d i e t a r y  between  f i s h  item  of  f i s h e s  (Table  Stimpson.  The  for  i t s  p r e d a t o r s  s p e c i e s  and  between  58  0.16  T  CO  •o  -0.10-1  1  1  1  O N D J  1  1  1  1  1  F M A M J  1977 Figure  1  1  1  1  1  1  1—I  1  J A S O N D J  1  F M  1978  1979  20a. Seasonal v a r i a t i o n i n the increment i n the p r o b a b i l i t y of death per u n i t time w i t h i n c r e a s i n g s i z e from c l a s s 4 t o c l a s s 5 f o r Neomysis m e r c e d i s a t Woodward I s l a n d . Positive values indicate increasing m o r t a l i t y r a t e s w i t h an i n c r e a s e i n s i z e ; The v a l u e s a r e g e n e r a l l y p o s i t i v e t h r o u g h o u t t h e p e r i o d from May t o September. 0.16T  - 0 . 1 0 - 1 — i — i — - t — i — i — i  O N D J 1977 Figure  1 — i  1 — i  F M A M J  1 — i  J 1978  A  S  1 — i  O  N  1  D  1—i  J  F  1  M  1979  20b. Seasonal v a r i a t i o n i n the increment i n the p r o b a b i l i t y of death per u n i t time w i t h i n c r e a s i n g s i z e ( f r o m c l a s s 5 t o c l a s s 6) f o r N e o m y s i s m e r c e d i s a t Woodward I s l a n d . Positive values indicate increasing m o r t a l i t y r a t e s w i t h an i n c r e a s e i n s i z e .  59  Table  4a.  C o e f f i c i e n t s of the m u l t i p l e r e g r e s s i o n model death rate = b per c a p i t a food r e s o u r c e s + c predator abundance f o r c l a s s 1 N. mercedis (n=13) .  2  v a r i a b l e  s t a n d a r d i z e d c o e f f i c i e n t +-'  salmon f r y d e n s i t y per c a p i t a food R  1.324 -0.551  ++-  R added  SE  0.240 0.240  0.74 0.09  2  0.83  Table  4b.  C o e f f i c i e n t s death 2 N.  of  rate = b mercedis  the  m u l t i p l e  r e g r e s s i o n  supply:demand (n=15).  index  f o r  model c l a s s  2  v a r i a b l e  s t a n d a r d i z e d c o e f f i c i e n t +-  supply:demand  Table  4c.  index  -0.714  +-  R added  SE  0.194  C o e f f i c i e n t s of the m u l t i p l e death rate = b supply:demand 4 N. m e r c e d i s (n=15).  0.51  r e g r e s s i o n index f o r  model c l a s s 2  v a r i a b l e  s t a n d a r d i z e d c o e f f i c i e n t +-  supply:demand  sampling p r o p o r t i o n i t s  index  d a t e s . of  N.  seasonal  There  abundance  f i s h  s e a s o n a l l y  ( F i g u r e  community. h e r r i n g ,  was  mercedis  p a r t i c u l a r  c o m p o s i t i o n ,  -0.581  s p e c i e s 21)  i n  i n  and  the  no  (Table  5 ) .  The  p r e d a t o r s response and -  on  t o s i z e  w i n t e r  s t a r r y  0 . 34  obvious of  f a l l  e s p e c i a l l y  +-0.226  d i e t  abundance, During  SE  the  as  R added  r e l a t i o n  i t s f i s h  N.  p r e d a t o r s  r e l a t i v e mercedis  changes  i n  s t r u c t u r e p e r i o d  f l o u n d e r s  between  and  importance  of  a l s o  changed  the  s p e c i e s  of  the  s c u l p i n s ,  accounted  the  f i s h smelt,  f o r most  of  60  1977  Figure  21. S e a s o n a l c h a n g e s i n t h e p r o p o r t i o n o f Neomysis m e r c e d i s consumed by p a r t i c u l a r f i s h s p e c i e s , 1977 1978 . L F S = l o n g - f i n n e d s m e l t , PH = P a c i f i c h e r r i n g , SF = s t a r r y f l o u n d e r s , SS = s t a g h o r n s c u l p i n s , PS = p r i c k l y s c u l p i n s , CS = c h i n o o k s a l m o n , and TSS = threespined stickleback.  0  1  O  1  N  1977  Figure  1978  1  D  1  J  1  F  1  M  1  A  1  M  1  J  1  J  1  1  A  1  S  O  1  1978  22. S e a s o n a l c h a n g e s i n t h e mean s i z e o f Neomysis m e r c e d i s consumed by f i s h a t Woodward I s l a n d , 1977 1978 . ( A ) i s t h e mean s i z e from f i s h s t o m a c h s , (•) i s t h e mean s i z e from C r a n g o n s t o m a c h s , and (0) i s t h e mean s i z e i n t h e p o p u l a t i o n .  61  Table  5.  C o n t r i b u t i o n  of  N.  SE) t o t h e d i e t s 1978. SS=stagh PH=Pacific h e r r i LFS=long f i n n e d chinook salmon, SS  date  mercedi s  of orn n g , smel and  f i s s c u TSS t, CF=  PH  PS  12-13/X/77  21.7 11.3 ( 1.8) ( 2 . 8 )  94. 3 ( 2 . 2)  16/XI/77  9.6 (4.1 )  16. 5 ( 2 . 0)  19-20/1/78  2.8 (0.3)  (average  TSS  LFS  0.5 (0.5)  3.5 (1.1) 1 . 1 (1.1)  12-13/IV/78  40.0 (0.0)  52. 2 ( 1 5 . 5)  volume  +-  SF  CF  CS  2.5 (2.5)  15-17/11/78  12-13/111/78  %  h e s a t Woodward I s l a n d , 1977 l p i n , P S - p r i c k l y s c u l p i n , =three s p i n e d s t i c k l e b a c k , SF=starry f l o u n d e r , CS= Crangon f r a n c i s c o r u m  5.6 (0.9)  34.8 (21.2)  4.4 (0.9)  100.0 (0.0)  3. 6 ( 3 . 6)  67. 4 ( 2 . 8)  18. 6 ( 5 . 4)  86. 3 (2. 1 )  6. 5 ( 6 . 5)  9. 6 ( 9 . 6)  7. 1  19-20/V/78  2.3 (0.3)  15.5 (1.9)  9.0 (0.7)  0. 3 ( 0 . 3)  23-24/VI/78  0. 1 (0.1 )  4.5 (0.6)  14.0 (0.5)  ( 1 .3 )  17.0 ( 1.3)  1 .2 ( 0 . 5)  19-20/VII/78  19.7 (1 . 7 )  14-15/VIII/78  2.9 (0.9)  14-15/IX/78  36.0 ( 1.3)  18-19/X/78  4.5 ( 1.2)  the  N.  through became salmon  m e r c e d i s t h e  t h e major was  12. 8 (5. 1 )  8.3 100.0 (0.0) ( 1.4) 33. 8 ( 4 . 8)  i n  p r e d a t o r s  through  3. 0  0.8 (0.3)  5.4 (0.7)  consumed.  e s t u a r y  14. 8 ( 2 . 4)  ( 1 .2 )  t h e i r  31.0 (2.8)  However,  as  s p r i n g ,  chinook  on  t h e m y s i d s .  n u m e r i c a l  j u v e n i l e salmon The  abundance  salmon  moved  f r y and  smolts  impact s i n c e  N.  of  t h e  m e r c e d i s  62  never  comprised  more  5).  Levy  a l .  e t  r e l a t i v e l y  s m a l l  (averaging  9.1%  consumed  most  as  t h e  r e s u l t  the  f i s h .  of  l a t e  summer  d i f f i c u l t  t o a s s e s s .  shrimp  was  used.  mercedis  ( S i e g f r i e d  Changes i n  t o  c l a s s e s  s i z e  i s  a t  o f  f i s h  d i f f e r e n t f i s h  (Figure  2 2 ) , f e l l  d r a m a t i c a l l y  s e l e c t i o n  f o r t h e s m a l l e s t  dominant  s m a l l  the  mysid  Smirnov N.  from  from  p o p u l a t i o n  mysid  The  s i z e  stomachs  p o p u l a t i o n  2-sample  mercedis  mysid  f i s h  on  t e s t ) . t h e f i s h ,  s m a l l  t h e C.  an  d u r i n g  a  salmon  s t i c k l e b a c k once  a g a i n  abundance  of  dominant  f i s h  f r a n c i s c o r u m  was  was  important  prey  t h e w i n t e r ,  t h e  t h e c o l l e c t i o n an  was  chinook  important  i n  community  methods  p r e d a t o r  p r e s s u r e mean  on  June  s i z e and -  A p r i l  mysid  median  l a t e  f a l l  J u l y  c l a s s e s  by  t h e  and  was  l e s s  t h e r e  was  and  a g a i n  from  t o t h e  no  those  of of  Kolmogorov  t h e mean  than  of  n u m e r i c a l l y  (p<0.05, J u l y  of  s p r i n g  d i s t r i b u t i o n s  s i g n i f i c a n t l y  June  s i z e  because  i n c r e a s e d  a l l o c c a s i o n s  stomachs  t o d i f f e r e n t  frequency  d i f f e r e d  I n  mysid  and  then  of  with  t h e  and  between  i n  i n t e r a c t e d  abundance  The  i n c r e a s e d  s t i c k l e b a c k s ,  v a l u e s .  and  t i m e s .  by  mysids  t h e f i s h  p r e d a t i o n  consumed  f a l l  by  t o be  mercedi s  n u m e r i c a l  of  (Table  1982).  mysids  p r e v i o u s  sampled  d i e t  p r e d a t i o n ,  mercedis  known  of  became  r o l e  s t r u c t u r e  s h i f t  f i s h  i n c r e a s e d  N.  N.  summer  5 ) , e s p e c i a l l y  i n t h e n a t u r e t h e  p o p u l a t i o n s i z e  (Table  i t  t o  that  d i e t  e a r l y  The  A l t h o u g h  t h e salmons'  found  s c u l p i n s  n o t q u a n t i t a t i v e l y  Elsewhere  changes  l o s t  m e r c e d i s .  f o r t h e shrimp  o f  t h e  I n  t h e g r e a t l y  on  N.  N.  of  volume).  t h e mysids  7%  a l s o  component  p r e d a t o r  item  about  (1979)  of  of  In  than  t h a t  d i f f e r e n c e  s i z e of  of t h e  i n t h e  63  means,  and  stomachs t e s t ) . were  i n was  G r a v i d  u s u a l l y  p r o p o r t i o n squared and  a l l other  in  that  females,  whose  broods  they  they  p r e d a t i o n  i n  i n  were  one  given  i n  from  f i s h  i n c r e a s i n g  mysid  s i z e .  The  s m a l l e s t  mysid  e a r l y  summer  (<0.001  day"  present  i n  from  f i s h  r a t e s  1  but )  the  were  remained  1  0.012  d a y "  r e s p e c t i v e l y )  were  observed  ranged  0.005  m o r t a l i t y  from  was  low  f a i r l y  i n c r e a s i n g The  l a r g e  c l a s s  summer,  A p r i l ;  however  c l a s s  i n  the  t r e n d  e a r l y  the  f i s h  became  the  M o r t a l i t y  low  same  (p>0.05,  c h i -  r a t e  d a y "  the d a y "  and  r a t e s  f a l l 1  .  ,  but  C l a s s  high  found  l o s s e s  d e c l i n e d  the  day" low  1  2  )  i n  v a l u e s  c l a s s e s  c l a s s e s  were 3  -  5  Maximal  0.045  day"  1  the  r a t e s  6  had  high  summer,  were  had  g e n e r a l l y  e a r l y  was  0.07  and  the  c l a s s  w i t h  on  v a r i a t i o n .  d u r i n g  s i z e  abundant.  1  r a t e s  the  on  summer,  o f t e n  extremely  w h i l e  temporal  0.030 i n  to  of  from  i n c r e a s e d  c l a s s e s  (maximum  values  l i t t l e  which  very  death  l e s s  ,  s p r i n g  a n i m a l s ,  the  the  e a r l y  g e n e r a l l y  r a t e s .  p r e d a t i o n  showed  v i s i b l e ,  r e s u l t i n g  i n  s i z e  0.015  u n t i l  7  t -  overrepresented  r a t e s  Except  t h e r e a f t e r  showed  and  6.  M o r t a l i t y  (about  between  f i s h  (p<0.05,  i n  were  l a r g e s t  at  p o p u l a t i o n .  p r e d a t i o n  the  very  p o p u l a t i o n  they  g r e a t e s t  d e c l i n e d  and  the  p r e d a t i o n  m o r t a l i t y  c l a s s e s  them  stomachs  m o r t a l i t y  Table  r a t e s  e l e v a t e d  p o p u l a t i o n  rendered  case  from  underrepresented.  m o r t a l i t y  g r e a t l y  i n  s i z e  the  f i s h  instantaneous  are  of  the  occurred  although  S i z e - s p e c i f i c f i s h  mean  than  as  cases  the  g r e a t e r  represented  t e s t ) , 2  cases  mysids  w i n t e r  but  w i t h  m o r t a l i t y a  e l i m i n a t e d only to  between  i n  f i s h A p r i l  s l i g h t i n  June.  s p r i n g  and  p r e d a t i o n  i n  and  June  as  Table 6.  Size s p e c i f i c  Sampling Date  Instantaneous m o r t a l i t y r a t e s on N. mercedis from f i s h p r e d a t i o n  (+- 1 SE).  Uropod Length C l a s s 0.3-0.8mm 0.8-1.3mm 1.3-1.8mm 1.8-2.3mm 2.3-2.8mm 2.8-3.3mm 3.3-3.8mm  10 October 1977  0 0041 (0 0025)  0 086 (0 054)  0 22 (0 14)  0 . 36 (0 .25)  0 089 (0 056)  16 November 1977  0 0057 (0 0012)  0 001 1 (0 0002)  0 0089 (0 0018)  0 029 (0 006)  0 043 (0 009)  0 14 (0 03)  0 0130 (0 0003)  0 036 (0 001 )  0 28 (0 01)  0 0058 (O 0012)  0 0087 (0 0019)  15 January 1978  0 00030 0 0037 (0 00001) (0 0001 )  17 February 1978  0 00010 0 00025 0 0027 (0 00002) (0 00005) (0 0006)  14 A p r i l 1978  o 012 (0 004)  0 0079 (0 0027)  0 0084 (0 0029)  0 0064 (0 0022)  0 17 (0 06)  25 May 1978  0 0018 (0 0004)  0 017 (0 004)  0 013 (0 003)  0 014 (0 003)  0 028 (0 006)  0 01 1 (0 002)  0 012 (0 0O3)  0 028 (0 006)  0 010 (0 002)  22 June 1978  0 074 (0 016)  0 028 (0 006)  0 015 (0 003)  20 J u l y 1978  0 012 (0 005)  0 0041 (0 0016)  o 0013 0 0029 (0 001 1 ) (0 0005)  17 August 1978  0 000042 0 00045 0 0027 (0 000014)(0 00015) (0 0009)  0 0061 (0 0020)  0 0093 (0 0030)  15 September 1978  0 000095 0 001 1 (0 000031)(0 0004)  o 026 (0 009)  ,-0 045 (0 015)  13 October 1978  0 000046 0 00050 0 0026 (0 000002)(0 00002) (0 0001 )  0 0060 (0 0003)  0 0097 (0 0004)  0 0098 (0 0033)  0 0030 (0 001 1 ) 0 001 1 (0 0003)  65  Di scuss ion  N.  mercedis  appears  t o  i n t h e t i d a l  produce  i n i t i a t e d  i n l a t e  i n c r e a s e  above  temperatures the  at  2.0-2.1 the  d e c l i n e  mm  mm.  o f  of  Animals  (W)  grow  November,  i n c r e a s e at  higher  s i z e s  below  between  of  6°C  on  each  as  and  of  eggs  (chapter  t h e  and  t h e  over  an  and  when  between 2.8-2.6  r e s u l t s  March.  T h i s , of  t h e  by  t h e  S1  October  a t  throughout  by  a  because  s m a l l o f  t h e  i n  (S2)  p e r i o d and  e a r l y  decreases j u v e n i l e s  and  a g a i n  e a r l y  uropod  June  l e n g t h ;  r e s u l t  i n or  temperatures  from  t h e t h e  p e r i o d .  t o d e v e l o p  i n a  August  extended  females  t h e m a t u r a t i o n  S1  (W)  A p r i l mm  i n  o v e r w i n t e r i n g  summer  r a p i d l y  embryos  e a r l y  mid  growing  mature  abundance  by  s l o w l y  m a t u r i n g  2)  and  temperature  grow  and  ( t h e  t h e  from  d u r i n g  a n i m a l s  b r o o d i n g  i n t h e l a t e  u n t i l  appear  i s c o n t i n u o u s  i n  when  j u v e n i l e s  g e n e r a t i o n  b r e e d i n g  October  produced  m u l t i p l e  i s  temperatures  mid  J u l y  mature  young  p r e s e n t  t h e l a t e r  November  s e a s o n a l i t y  i n  and  of  of  decrease  f a i l u r e  about  August  a n i m a l s  temperatures  The  Young  o v e r w i n t e r  which  These  d e l t a  B r e e d i n g  water  hatched  l e n g t h .  R i v e r  y e a r .  u n t i l  i n l a t e  hatched  i n t h e s p r i n g ,  as  t o mature  spreads  These  s i z e s  s m a l l e r  May.  r a p i d l y  and  immatures.  m i d - l a t e  i n i t i a l l y  the f a l l  Newly  because  which  per  c o n t i n u e s  p r o d u c t i o n  g e n e r a t i o n ,  t h e F r a s e r  A p r i l  s h a r p l y .  females  s i z e s  s p r i n g .  and  i n e a r l y  The  of  g e n e r a t i o n s e a r l y  uropod  p e r i o d  p r o p o r t i o n  -  q u i c k l y  appear  summer  range  i n  grow  2.0-2.1  g e n e r a t i o n  March 6-8°C,  p o p u l a t i o n  g e n e r a t i o n )  t h r e e  marshes  a t  c e s s a t i o n  i n t u r n , mysid.  temperatures of  imposes  b r e e d i n g a  marked  S t a n d i n g  c r o p s  66  (#«nr ) 2  of  d e c l i n e  30-40«m"  i n c r e a s e s the  2  c o n t i n u o u s l y d u r i n g i n  q u i c k l y  p o p u l a t i o n  I000«m~  2  e v i d e n t  o f  i n c r e a s e d  Body  commences,  c o n j u n c t i o n  changes  which s i z e  c r u s t a c e a n s  the  i n  a d u l t  d u r i n g  a s c r i b e d  a t  v a l u e s  Abundance of  young  t o  d e n s i t i e s  near  i n abundance  there  p e r i o d .  changes  t r a i t s  of  t h e mysids,  s i z e  a t  t h e  m a t u r i t y  most  and  an  g e n e r a t i o n s .  t h e  summer 1980,  1983).  has p.  a t t r i b u t e d  v a r i a t i o n t o  and  (Heubach  i n t h e s i z e  temperature  d i f f e r e n c e s  a t  been  a n d ,  i n  e f f e c t s  and  (Corkett 1982)  K l e i n  B r e t e l e r  and  s m a l l e r  body  s i z e  Neomysis et, a _ l .  Leptomysis on  1980;  and Gonzalez  r e p o r t e d  1969; Toda of  n u t r i t i o n  1972; N o r t h c o t e  1980a;  t o  115; de  B r a m b i l l a  M a t u r a t i o n  f r e q u e n t l y  1978, p.  1976;  B r e t e l e r  ( V i d a l  511;  a t t r i b u t e d  1982),  i n t r i n s i c  i n  1970, p.  Landau  ( S t r o n g  K l e i n  204,211)  t o temperature  Seasonal  123;  or  been  and McLaren  p r e d a t i o n  common  856; Kinne  V i j v e r b e r g  i n c o m b i n a t i o n  1982; Sheader  f a i r l y  has v a r i o u s l y  1976),  p.  i s  1967, p.  ( C o r k e t t  1960;  1982),  1978, o r  s i z e  1980; Armitage  1975; Stenson  (Mauchline  body  temperature  1958; Deevey  s i n g l y  Gonzalez  r e c r u i t m e n t  f a l l  decreased  1980) and  C u l v e r  McLaren  a c t i n g  e a r l y  h i s t o r y a  s p r i n g .  s t a b i l i z e s  i n t h e summer  1981; Elmore  C l a r o t t o and  o f  1978;  Evans  a s  t h e seasonal  a r e  1980; C u l v e r  (Richman  summer  ( e . g . H u t c h i n s o n  e f f e c t s  March  -  e a r l y  t o minimum  V a r i a t i o n  V a r i a t i o n  Nelson  w i t h  and  and  summer  i n t h e l i f e  egg  S i z e  w i n t e r  i n t h e e a r l y  i n t h e l a t e  In occur  l a t e  t h e w i n t e r  i n ,  has  1982,  1ingvura  metabolism  mysids been 1983).  has  (Gaudy  been and  67  Guerin  1979).  I n t e r p o p u l a t i o n  m a t u r i t y  i n  M y s i s  r e g i o n a l  d i f f e r e n c e s  V a r i a t i o n of  both  most  N.  i n  proximate  important  s i z e  at  reared  s i n c e  the  at  animals  the  decreased  may  r e s u l t  r e a r e d -  h y s t e r e s i s  s i z e  depending  dependence  d u r i n g  e a r l y (de  o p t i m i z e  Seasonal  has  i n  amount at  temperature  e f f e c t s .  than  l e v e l s .  v a r y i n g  same the  body  number  s i z e of  20°C  The  showed  was  d i s c u s s e d  i n  by  f l u c t u a t i n g  a v a i l a b i l i t y  body  r e a r e d over  i n  beyond may  a  a  i n  f i x e d  wide  p r e r e p o d u c t i v e  not  H y a l e l l a mechanism  environments.  at  f o r  a  m a t u r i t y  of  a t t r i b u t a b l e  a q u a t i c  be  a  i n s t a r s  of  to more  c r u s t a c e a n s  temperature  range  A  e x p e r i e n c e d  account  s i z e  that  change.  a  g e n e r a l l y  s i z e  at  as  w i l d  marked  amphipod  thermal  d i d  v a r i a t i o n  a d u l t  her  the  d e r i v e d  a  temperature  the  than  of  f i e l d  temperatures  of  I s l a n d ,  20°C.  f o r  i n  l e s s  h i s t o r i e s  r e p o r t e d  the  temperature.  thermal  on  be  l a b o r a t o r y  Woodward  7b)  terms  r e d u c t i o n  was  s i z e  Temperature  Daphnia  at  may  w e l l - f e d  at  (Figure  I s l a n d  of  of  i n  p o p u l a t i o n  of  the  Woodward  d e t e r m i n a n t  the  food of  important  at  and  I s l a n d  d i r e c t i o n  been  r e p r o d u c t i o n  s i g n i f i c a n t  food  the  a d u l t  1978)  v a r i a t i o n  mercedis  of  l i f e  March  on  summer  s i z e  a t  r e l a t i o n  to  i n c r e a s i n g  e a r l y  m a t u r i t y  a t t r i b u t e d  w i t h  temperatures the  at  1980).  the  m a t u r a t i o n  body  s i z e  be; d i s c u s s e d  Woodward  a d u l t  the  Temperature  i n d u c i n g  s i m i l a r l y  from  t o  s i m i l a r  N.  i n  may  i n  were  (Morgan  c a u s e s .  the at  Tahoe  t r a i t s  f a c t o r  s i z e  decrease  temperature  to  u l t i m a t e  i n  Lake  l e v e l s  h i s t o r y  c o r r e s p o n d i n g  d i f f e r e n c e  a z t e c a  food  l i f e and  w i t h i n  proximate  a n i m a l s  Although  i n  m a t u r i t y  mercedis  that  r e l i c t a  d i f f e r e n c e s  food  matured  l e v e l s  (Anderson  by  1932;  68  N e i l l  1981a).  N e i l l ,  However,  p e r s .  been  case  s i n c e :  reared  an  n u t r i t i o n  (1) growth  r e l a t i o n  d i d not  and  r e p r o d u c t i v e  i n d i c a t o r s  of  fact  animals  r e p r o d u c t i o n  2 ) , and  vary  does  not  l e v e l s .  Both  d e c l i n e d  throughout  per  s t a t e  food  a t  t h e  food  l e v e l s  i n c r e a s e d  w i t h  Because  increment  i n p r o b a b i l i t y  with  temperature,  to  a  of  s i z e  t h e r e  p r o b a b i l i t y s e l e c t i o n  body of  c l a s s e s  a g a i n s t  a t  s u r v i v a l .  a g a i n s t  environmental  s i z e  -  female  g e n e r a t i o n s .  Growth  regarded  as  a n i m a l .  However  d u r i n g  f o r normal that  s e n s i t i v e  t h e  t h e summer  growth  and  l a r g e r  animals  w i t h  f i n d  adequate  food  a l s o  supply:demand  o f  f u r t h e r t o  Seasonal  temperatures  N.  c o u l d  m a t u r i t y  l a r g e  strong r a t e s  i n c r e a s i n g  p h y s i o l o g i c a l response  reduced  was  M o r t a l i t y  temperature  s e l e c t i o n  present  l a b o r a t o r y  weight  s i z e  and  c o n s i s t e n t l y  f o r t h e mature  of  t o  i n d i c e s  summer.  October  s i z e  an  would  2 0 ) .  t h e  1978  imply  requirements  s i z e  t o those  small  ( F i g u r e  a  (W.E.  i n t h e  r e s o u r c e s  n e c e s s a r i l y  c a p i t a  of  s i z e  Thus  g e n e r a l  a d u l t  t h e  t o  i n t e n s i t y  be  i s u n l i k e l y  t h e c l u t c h  May  body  not  p o p u l a t i o n  commonly  matured  s u f f i c i e n t  of  (2)  a r e  which  metabolic  large  may  s i m i l a r  between  output  greater  From  were  t h e n u t r i t i o n a l  had  f i e l d  m o d i f i e r  r a t e s  (chapter  s i z e  a p p a r e n t l y  response  i n t h e  important  animals  that  a  comm.).  Inadequate have  such  animals may  of  s e l e c t i o n (from  death  w i t h  i n c r e a s i n g  was  c o r r e l a t e d  a  i n c r e a s e d  summer.  p r e d i c t o r  i n c r e a s e  i n  r e s u l t i n t h e  was  of  body  temperature  v a r i a t i o n  promote  sources)  d u r i n g  be  which  a l l  s i z e  mercedis  would  a g a i n s t  i n  l e d  higher  i n t e n s i t y  c o r r e l a t e d  g e n e t i c  s i z e .  that a  t h e  of w i t h  mechanisms  69  u n d e r l y i n g at  a  temperature-dependent  S i z e  i n  (Wigley  and  1973a;  B r a t t e g a r d  and  i n t e g e r .  N.  Burns  p o p u l a t i o n  however, eggs  than  times  s i z e  i n  q u i t e  N.  t o t a l  r a t h e r  egg  f o r  1955;  a_l.  about  the  c l u t c h  the  ranges v a r y  of  may  weight  The  t o  1969;  changes  c o n s t a n t  v a r i a t i o n  i n  change of  times The most  mean  egg  egg f o r  which seasonal  Neomysis  Mauchline  between i n  1.56  r e p o r t e d  observed.  i n  the  the  r a t i o s  f o r  the  reduces  would  2.25  r e p o r t e d  t o  customary  e r r o r :  d i a m e t e r s  Heubach  remains  M y s i d a c e a .  I  l a r g e r  Changes  the  observed  1.35  which  r e p r e s e n t  s e a s o n a l  egg  from  1964;  I  t i m e s .  f e c u n d i t i e s  Murano  Thus  which  and  c a s e s ,  c a r r i e d  weights  measurement  1.17  v a r i a t i o n  1979)  t o  weights  americana the  than  two  I s l a n d .  d i a m e t e r s  to  i n  Woodward  a  1973a)  c o n t r a s t  egg  m e r c e d i s .  common  i n  amer i c a n a w i t h i n  these  females  females,  r e l a t i v e  N.  (Mauchline In  mysids  Mauchline  s i z e  because  s i z e - a d j u s t e d  e_t  egg  o v e r l o o k e d  N.  (Kinne  i n  commonly  c a l c u l a t e d  i n  i n c l u d i n g  g e n e r a t i o n  at  s e v e r a l  1972;  be  by  s i m i l a r  1979)  1981b).  mercedis  o n l y  S i e g f r i e d  as  N.  f o r  L a n g f o r d  i n t e g e r  summer  d i a m e t e r s  and  N.  w i n t e r  egg  i n t e g e r  the  f o r  r e p o r t e d  changes  (Wittmann  mean  s p e c i e s  if  Baychorov  i n  volumes  changes  and  d i f f e r e n c e s  change  egg  are  of  of  Lasenby  s m a l l e r  may  magnitude  been  f o r  l a r g e r  seen  measurement  has  Seasonal known  the  s i t u a t i o n  s i z e  1974;  l i n g v u r a the  s i z e  egg 1971;  are  Leptomysis  N.  i n  Var i a ti o n  V a r i a t i o n  the  p l a s t i c i t y  m a t u r i t y .  Egg  egg  phenotypic  egg  1971; s i z e  g e n e r a t i o n s  s i z e  may  be  70  Seasonal r e p o r t e d  f o r  c l a d o c e r a n s 1982),  egg  (Brody  (Green  1966;  and  1984).  temperatures  and/or  food  proximate  f a c t o r s  on  c o m p e t i t i o n The N.  are  at  temperatures Nelson  L a t i t u d i n a l c o l d e r  f o o d ,  magnitudes  a s s e s s .  In  on  p o r t i o n  of  D i e t  known  1973;  et  the  and  i n are  d i f f e r e n t  i n  summer  seasonal egg  number  a_l.  1981)  and  i n  Lampert  and  1982;  the  McLaren  l a r g e r and  are d i r e c t  accounted  Sheader  f o r  1978; 1983).  eggs  B i r d  w i t h 1980).  e f f e c t s  of The  d i f f i c u l t  to  e f f e c t s  of  o n l y  a  ( B r a m b i l l a  mysid  other  f o r  of  h i g h e r  d i f f e r e n c e s .  the  the  data  w i t h  s i m u l t a n e o u s  numerous 1978;  1966).  Sheader  v a r i a t i o n i n  w h i l e  s i z e - r e l a t e d  to  a s s o c i a t e d Hart  the  g e n e r a t i o n s  c o n t r a s t  f a c t o r s  Daphnia  as  m o r t a l i t y  (Cody  Dolah  experiments  s i z e  or  a s s o c i a t e  the  environmental  d i f f e r e n t i a l  causes  1978), isopods  v a r i a t i o n  the  Van  a f f e c t  1976;  and  s i z e  B r a m b i l l a  to  V i j v e r b e r g  1983),  regarded  1975;  1980;  McLaren  i n t e r p o p u l a t i o n  of  observed  i s  eggs  confound  egg  i n  s i m i l a r l y  l a b o r a t o r y  temperature  (Johns  1980;  data  eggs  B r a m b i l l a  and  p r e d a t i o n  u l t i m a t e  1980;  i n  been  i n c l u d i n g  o f t e n  s i z e  S t e e l e  (Nelson  r e l a t i v e  i s  and  comparisons  f i e l d  i n  I s l a n d  s m a l l e r  C u l v e r  temperature,  the  l a r g e r  where  environments  However  of  ( S t e e l e  1980;  egg  s i z e - s e l e c t i v e as  Hart  v a r i a t i o n  are  have  groups  C u l v e r  Sheader  Seasonal l e v e l s  Woodward  c r u s t a c e a n s  1975a;  v a r i a t i o n  invoked  o c c u r r e n c e  mercedi s  most  from  1974;  p.659;  i n d u c i n g  seasonal  j u v e n i l e s ,  1967,  S t e e l e  p o p u l a t i o n s  c r u s t a c e a n  K e r f o o t  Lawlor  ( p r e d i c t a b l e )  w i t h i n  other  (Hutchinson  (Steele  and  c y c l e s  numerous  copepods  amphipods  s i z e  M y s i d o p s i s  c r u s t a c e a n s 1983)  but  s m a l l 1982). bahia (Smyly food  71  e f f e c t s  on  egg  s i z e  r e s u l t e d  i n  B r a m b i l l a  1980)  s m a l l e r but  (Brody  and  adverse  c o n d i t i o n s  (Dixon  and  o f t e n the  The N.  response between  t o  g e n e r a t i o n s  Food  m a t u r i t y and  The i n  N.  mercedis  T h e i l a c k e r  1971;  v i t e l l o g e n e s i s somatic  might  decrease  i s  growth  l a s t  i n t e r m o l t s  1inqvura  (Wittmann  decrease  i n  N.  i n t e g e r  weight,  s i z e .  In  about  19%  N.  has  r a t h e r et  mercedis the  and by  In  s t o r e s low  a_l.  the  N.  o t h e r  the  the  f i r s t  (Raymont  from  energy  i n  p e r i o d over  (13%  l i k e l y  e x t r u s i o n the much  of  the  the  a  body food  i n f l u e n c e s  c l u t c h  by  Since  that  of  the  Leptomysis  1966).  egg  so  of  accompanied  i s  weight  that  o c c u r s  i t  of  sexual  ( C l u t t e r  the  a_l.  i n  suggests  c l u t c h  r e s e r v e s  weight  t o t a l  et,  s i z e  mysids  i n  i t i s  i n  d i f f e r e n c e s  egg  d i v e r s i o n  i n t e g e r  p r e c e d i n g  v a r i a t i o n  p r e c e d i n g  V i t e l l o g e n e s i s  1974)  d a t a .  1979)  p r o d u c t s  1964),  female's  and  i s  p h y s i o l o g i c a l  the  r a t e  l i p i d  dry  s i z e  growth  and  F r e t w e l l  i n f l u e n c e  i n  aphids  i n f l u e n c i n g  i n t r i n s i c  w i t h  under  as  I983a,b),  d i r e c t  G u e r i n  p r e c e d i n g  immediately  of  2)  l a y i n g .  1981a).  l i p i d  a v a i l a b i l i t y  the  ( c h a p t e r  egg  body  Raymont  i n  r e p r o d u c t i v e  b e f o r e  s e v e r a l  c o n s i s t e n t  young  such  and  1956;  Armadi11ium  l a r g e r  egg  nor  d i r e c t l y  Gaudy  immediately  Smith  a  l e v e l s  (Green  f a c t o r s  s e a s o n a l  a c c o m p l i s h e d  t o  t o  N e i t h e r  i s w h o l l y  of  (Stearns  1951;  l i m i t a t i o n  i s o p o d  organisms  f i s h  induce  Food  Daphnia  the  response  r e s o u r c e  a v a i l a b i l i t y  Neomysis.  and  o b s c u r e .  v a r y i n g  i n  o t h e r  (Hutchinson  which  i n  p r o d u c t i o n  a d a p t i v e  young  remain  young  i n  1982)  r e p o r t e d .  b i r t h  The  known  an  f a c t o r s  mercedis  l a r g e r  W e l l i n g s  of  commonly at  1984). i s  as  l e s s s i z e  i n  Lawlor  d i s c u s s e d  s u r v i v a l  are  egg  averages a n i m a l ' s  72  energy  s t o r e s  The s p r i n g in  would  be  u t i l i z e d  i n v a r i a n c e  o f  t h e f e c u n d i t y  g e n e r a t i o n s  egg  s i z e  d i f f e r e n c e s maternal  p r o v i d e s  may  w e i g h t s ,  egg  which  between  female  s i z e s ,  r e s u l t e d  as  from  occurrence  o f  of  u n l e s s  d i f f e r e n t instance that egg  t h e  1979  s i z e  argues  weight  against  b i m o d a l i t y .  v a r i a b l i t y  i n egg  body  s i z e  d i f f e r e n c e s  i n  s p r i n g  summer  and  from  s p r i n g  of  egg  s i z e  and  g e n e r a t i o n s  d i f f e r e n c e s i n  s i z e  forms  r e p r e s e n t  not  g r a v i d  do  d e t e r m i n a t i o n  n o t  -  as f o r  show  s i z e s  q u i t e  t h e  r i v e r  egg  t h e  s p r i n g  p o s s i b l e ,  f a c t  bimodal  d i s c h a r g e g e n e r a t i n g seen  a t  a l l  i n t r a p o p u l a t i o n  e n v i r o n m e n t a l  f e c u n d i t y  do  1978  t h e mechanism  throughout  body  Moreover  p o p u l a t i o n s ,  weight  mean  e x p e r i e n c e d  i s  of  s i z e  d i f f e r e n c e s  i n t h e  have  i n  egg  t h e mean  c o n s i d e r a b l e  c l u t c h  r e l a t i o n s h i p s  as  range  s i m i l a r  t h e  t h e  f a c t o r s ,  s i m i l a r  i s  t o  do  g e n e r a t i o n s  broad  response  n u t r i t i o n .  u p r i v e r  immigration  under  nor  t h i s  d e s p i t e  s i z e  e n v i r o n m e n t a l  females  there  s i z e  an  egg  v a r i a t i o n  c o n d i t i o n  egg  A l t h o u g h  The  that  c o n s t a n c y -  with  that  that  i f t h e egg  s m a l l  immigration  i m p l i e s  The  and  1980  s u g g e s t i o n  i n t h e  v a r i a t i o n  t h e s i z e - a d j u s t e d  i n maternal  d i f f e r e n t  and  as  expected  d i s t r i b u t i o n s ,  1978  periods  l a r g e  i n  r e l a t i o n  y e a r - t o - y e a r  g e n e r a t i o n s  e n v i r o n m e n t s .  p a t t e r n s , the  be  s i z e  i t i m p l i e s  i n t e r p r e t e d  i n c o n s i s t e n t  through  as  However,  s p r i n g  both  body  p h y s i o l o g i c a l  r e f l e c t e d  d i f f e r e n c e s  i s  s i z e  be  might  g e n e r a t i o n egg  a r e  t h e  a  s t a t e ,  number.  can  strongest  i n p a r t ,  e f f o r t  than  vary  b e ,  -  c o n s i d e r a b l e  t h e  n u t r i t i o n a l  r e p r o d u c t i v e rather  d e s p i t e  f o r v i t e l l o g e n e s i s .  body  1978 seen  c o n d i t i o n s . s i z e  imply between  v a r i a t i o n  and that  body t h e  t h e 1978 i n  t h e  73  a l l o c a t i o n  of  d i f f e r e n c e s  i n t h e a v a i l a b i l i t y  s i z e  d i f f e r e n c e s  i n d i v i d u a l s  I n d i c e s  of  of  food  mean  egg  response  t o a  as  seen  c o u l d  eggs  s i z e  l a r g e  i n  f e c u n d i t y  by  (Wittmann by  3 5 % .  copepod  development  about  l a r g e r small  than  1981b), 16%.  eggs  p e r i o d  on  t h e  i f s e x u a l  t o o s m a l l  growth  i n  weight  egg  r e p o r t s  m o r t a l i t y  improve  d u r i n g  t h e e a r l y  Since  o c c u r s  t h e  eggs  o f  were  a  s i z e  female's  s i n c e  o f  weight  t h e age c o n s t a n t  However, b r e e d i n g  g e n e r a l l y  s i z e  i n mean  time  neonates,  t h e  t o s e x u a l  egg  i n  t h e egg  t h e egg  r e s u l t  s p e c i f i c  a f f e c t  e x p o n e n t i a l a t  body  -  s i t u a t i o n  that  part  a d u l t s  a  and  i n c u b a t i o n  than  h a t c h i n g a t  t h e  s m a l l  t h e  s i m i l a r  o f  important  s u r v i v o r s h i p .  d i f f e r e n c e  s i g n i f i c a n t l y i s  o f  l a r g e r  m a t u r i t y  weight  power  such  1984).  s e v e r a l  Moreover,  average,  increase  p h y s i o l o g i c a l  p r o d u c i n g  a  i s l e s s  r a t e s  a  reduced  i n c r e a s e s  from  t o  eggs  c o n d i t i o n s .  t h e  Lawlor  c l u t c h  t h e 0.31  i n t e r v a l  A l t h o u g h  appears  same  be  has  females  so  t h e  a v a i l a b i l i t y ,  and  s i z e  m i n u t u s . as  may  i n food  i n egg  (1965)  m o r t a l i t y  neonates.  i n summer  (Brody  l a r g e  t h e l a r g e r  produced  t h e  o f  t e m p e r a t u r e .  o f  i n c r e a s e s  I f a d u l t  were  h a t c h l i n g s ,  decrease  t h e  e n v i r o n m e n t a l  summer  Because  McLaren  would,  when  those  reduced  d u r i n g  Pseudocalanus p e r i o d  eggs  d e c r e a s e  had  t h e p r o d u c t i o n  the  d i f f e r e n t  v a r i a t i o n  r e l a t i o n ,  Egg  i n  A r m a d i l l i u m  1978  f o r r e p r o d u c t i o n .  d i f f e r e n c e s  consequences.  eggs  than  g e n e r a t i o n s o r from  ( p r e d i c t a b l e )  I n t r a s p e c i f i c  rather  between  under  from  energy  young  d i f f e r e n c e s  seen  isopod  o f  among  i n t r i n s i c  a v a i l a b i l i t y  i n t h e  demographic  r e s o u r c e s  r e s u l t  i n d i f f e r e n t  p r o v i s i o n i n g  in  e q u i v a l e n t  i n  l e s s l a r g e r  m a t u r i t y a t  i s  a  given  s i z e  (I6yg)  a t r a t e ,  m a t u r i t y , so  s m a l l  74  i n i t i a l  d i f f e r e n c e s  (Lawlor at  1976;  m a t u r i t y  s u r v i v a l agents  Kaplan  as  m a t u r i t y . by  such  i n  d e c r e a s i n g  the  i n  the  p o p u l a t i o n  age  r  produced assumes  in  •  i s  V a r i a t i o n  age  at  can  i n  reduce  m a t u r i t y  the  the  s i z e  age  may  exposure  egg  at  i n c r e a s e  to  m o r t a l i t y  l e n g t h , S  i s  most then the  i n  f e c u n d i t y  through  the  be  r a t e  of  through changes  p o t e n t i a l  from  and  the  r a t e  (McLaren  w i l l  i n of  1963)  i n  eggs  reproduce  w i t h i n  the  small i n egg  be  s u c c e s s i v e  by  s i z e  i n c r e a s e s  s i z e  W  and f o r  the  l e n g t h  eggs [7]  approximately i s  continuous  g e n e r a t i o n s only sum  The  of  egg  S2 S1  the  V a r i a t i o n  from i n  i s  once.  p e r i o d .  egg  the  generation  the  of  Equation  there  approximated  from  number  s u r v i v o r s h i p .  p r e - r e p r o d u c t i v e  l a r g e r  i s  although  females  r e s u l t s  for  and  on  but  between  produced ,  E  the  case,  r e s u l t i n g  1  the  f e c u n d i t y ,  estimated  generations  and  i n f l u e n c e  i n  s i z e  roughly  l e n g t h  d a y "  t h e r e f o r e  changes  of  o v e r l a p  may  d i f f e r e n c e i n  the  r e p r o d u c t i o n ,  and  and  p e r i o d  0.001-0.002 no  the  4)  g e n e r a t i o n  f u r t h e r  of  progresses  ln(E-S)  present  l e n g t h  g e n e r a t i o n  but  [1/D]  the  development  be  g e n e r a t i o n  s i n c e  g e n e r a t i o n  in  =  can  female,  ( F i g u r e  w i l l  s i z e  f i r s t  non-overlapping  b r e e d i n g , low  the per  c o r r e c t  time  reduct ion  r i s e  d u r a t i o n  e f f e c t s  i n c r e a s e  i s  as  Simultaneous  through  at  The  [7]  D  egg  i n c r e a s e  i n  a m p l i f i e d  p r e d a t i o n .  s u r v i v o r s h i p .  where  1980).  Reductions  V a r i a t i o n  changes  g r e a t l y  temperatures  as  p o p u l a t i o n  are  which  r,  of  the  about  generations g e n e r a t i o n .  r e s u l t i n g  from  75  the  egg  s i z e  i n c r e a s e s a l l  i n  eggs  young  T h i s  compensate i f  the  f o r  Seasonal on  dependence the of  age the  at  r  the  of  average  g e n e r a t i o n  r e d u c t i o n  concommitant i n  i n  (1967,  the  of  rate  i n  1  )  from  l a r g e l y  s i z e  p.85)  brood of  may  female  10  from  1  ) ,  assuming more  s e n s i t i v e changes  t o  than  of  can  s i z e s  egg  s i z e . l a r g e r  t e m p e r a t u r e s i z e  s i z e ,  reduces t h a t  of  the  reduces  the  (Table  3 ) .  summer  no  g e n e r a t i o n  that  of  the  m o r t a l i t y .  compensates  Lewontin  (1965)  t o  changes  i n  f e c u n d i t y  r  Thus,  much  25-30  " i n g e n e r a l  egg  o n e - t h i r d  times  be  i n  egg  because  the  1.6-2.2  f e c u n d i t y .  that  of  of  number.  a d u l t  on  t o  eggs  The  a l s o ,  from  s u r v i v o r s h i p  have  but  r  cause  s m a l l  egg  of  i n  d i f f e r e n c e s  d i f f e r e n t  and  i n c r e a s e  f o r  the  from  g e n e r a t i o n s  t o  l e n g t h  c l a i m  i n  i n  eggs  d i f f e r e n c e s  independent  2)  i s about  t o  the  v a r i a t i o n .  summer  d a y "  i s more than  those  f e c u n d i t y  per  u l t i m a t e  s m a l l  young  eggs  the  r e d u c t i o n  ( c h a p t e r  g e n e r a t i o n  r  t o  of  seasonal  temperature  egg  (0.015  r e p r o d u c t i o n  W i l s o n  i n  day"  r e d u c t i o n  g e n e r a l ,  be  s m a l l  i n c r e a s e s  causes  s m a l l  that  i s  g e n e r a t i o n ,  young  w i n t e r  and  of  dependence  (0.025-0.030  f i r s t  would  f o r  s u r v i v a l  from  neonates  r a t e s  m a t u r i t y  p o t e n t i a l  t h a t ,  r  does  females  the  r e l a t i v e  of  ,  However,  s m a l l  concommitant  growth  number  young  m e r c e d i s .  eggs  r a t e s  then  young  1  the  suggest  on  i s produced  day"  Thus,  of  c o u l d  N.  o v e r w i n t e r i n g  average  4 ) .  that  v a r i a t i o n  of  g e n e r a t i o n  R e l a t i v e l y  than  e x p o n e n t i a l  The  i n  l a r g e  l i t t l e ,  e f f e c t s  0.001-0.005  m o r t a l i t y  m o r t a l i t y  v a r i e d  about  r e s u l t  s m a l l . from  the  exceed  v a r i a t i o n q u i t e  which  (Appendix  s i z e - s p e c i f i c  s i z e  of  of  must  i n c r e a s e d .  are  r,  g e n e r a t i o n s  l a r g e  in  from  i n  and  s m a l l  f o r  has  the  Thus the  argued age  at  MacArthur  changes  i n  76  developmental to  l a r g e  the  r a t e s  i n c r e a s e s  e f f e c t  may  be  o f  t h e order  of  10% a r e r o u g h l y  i n f e r t i l i t y  of  dependent  t h e magnitude  on  t h e order  of  e q u i v a l e n t  100%."  o f  However  f e c u n d i t y  (Cole  1954).  Demography  Maximum occur 0.03 to  i n  p e r c a p i t a  t h e 1  d a y " reduce  f o r t h e r e s t  a  a  d e c r e a s e s  an  a  comprised Decreases a  by  c l e a r are  r a t e  n o t .  higher  Several  t h e s i z e  of  i n c l u t c h  near  f a c t o r s  1  )  0.01-  combine  t h e  females  a t  m a t u r i t y ,  s i z e ,  mean  egg  decrease  i n t h e p r o p o r t i o n  r e d u c t i o n  i n t h e p r o p o r t i o n  t h e a d u l t  s i z e ,  which  a l s o  of  t h e a d u l t  females  age  a t m a t u r i t y  t h e  I n  o f f s e t  t h e preceding  r a t e  through  d e n s i t y  t h e r o l e  that  summer  p o p u l a t i o n  of  temperature  f a c t o r s  t o  a  d e c l i n e s . which  t h e  l i m i t a t i o n of  a r e l i m i t e d  N. by  i n t h e  occurred  i n d u c i n g  food r a t e s  t h e d e c l i n e  p e r i o d  f a c t o r s  t h e b i r t h p e r i o d  i n c r e a s i n g  summer  t h e proximate  p a r t i c u l a r ,  d e n s i t y  w i t h  t h e b i r t h  t h e high  Evidence  t h e  p e r i o d  mechanisms  above),  o f  females.  t h e i n c u b a t i o n  d u r i n g  ( s e e  ambiguous. the  t o v a l u e s  day"  s i z e ,  b u t n e v e r t h e l e s s  A l t h o u g h b i r t h  a  i n  reduced  degree,  d e c l i n e  (0.27  r a t e :  i n  i n  r a t e s  g r a v i d , (4)  and  b i r t h  i n c r e a s e  b i r t h  t h e summer.  decrease  t h e c l u t c h (3)  a r e  of  decrease  corresponding (2)  that  b u t q u i c k l y  t h e per c a p i t a (1)  w i t h  s p r i n g ,  instantaneous  a r e  changes remains  mercedis  d u r i n g  d e c r e a s e s  i n t h e  77  r e l a t i v e  a v a i l a b i l i t y  mechanisms  through  of  food  which  remains  such  weak,  an  a l t h o u g h  e f f e c t  c o u l d  numerous  occur  remain  p o s s s i b l e . Food  a v a i l a b i l i t y  c r u s t a c e a n s Durbin N.  ( e . g .  SLI.  et  mercedis  (Figure  17a)  number  of  c o r r e l a t e d  1983).  Woodward.  and  was  eggs  per  of  decrease  i n  s i z e  the  temperature  June  F u r t h e r ,  the  p o p u l a t i o n r a t e s  the  of  s i z e , The  not the  which  d e c r e a s e  i n  t h a t  a l l o c a t e r u l e  of  out  of i n  due  good  c l u t c h  those  c l u t c h the  o t h e r of  amounts e f f e c t s a d u l t  c l u t c h  of of  which  food  females  were  from  the  be  mass  t o  a b l e  p r i m a r i l y due t o  of  h i g h . f i e l d  the  growth  2 ) . c l u t c h  i n  the  the  s i z e , summer  mean  remained  breed  The  b r e e d i n g  egg  c o n s t a n t .  however, t o  food  d e c l i n e  the  merely  were  able  I t  does  r e p r o d u c t i o n .  were  t o  s t i l l  i n f l u e n c e  l i m i t a t i o n .  which  p a r t l y  w i t h  r e l a t i o n ,  energy  the  was  i n  average  p o s i t i v e l y  began  s i z e s  summer  i n  ( c h a p t e r  i n c r e a s e  weight  a n i m a l s  t o  f o r  change  component  a n i m a l s  t o  was  t o  m a t u r i t y  1980;  food  the  e f f e c t  agreement  expected  t o  r e s u l t s appears  that  r e a r e d  a r e  at  of  s p r i n g  The  a d d i t i o n a l  numerous  Checkley  r a t e  a v a i l a b i l i t y  s i z e - a d j u s t e d  s i m i l a r  p r o p o r t i o n  s i z e  i n  w i t h  b i r t h  which  body  was  from  c r o p .  no  r a t e s  l e v e l s  the  the  w i t h  food  1978;  a v a i l a b i l i t y  female  s i z e - a d j u s t e d  the  c o n s t a n c y  a d u l t  r e l a t i v e  appears  Lampert  c o r r e l a t e d  female;  l a b o r a t o r y  food  s i n c e  the  f e c u n d i t y  d e c l i n e d  m a t u r i t y ,  matured  females  I s l a n d  per  at  growth  w e l l - f e d  i n d i c a t e s to  when  1976;  s t a n d i n g  response  A l t h o u g h  b r e e d i n g  eggs  a f f e c t  r e l a t i v e  a d u l t  Moreover,  e a r l y  to  p o s i t i v e l y  meiofauna  number  in  The  a t  w i t h  v a r i a t i o n .  known  V i j e r b e r g  average  a  i s  r e d u c t i o n may  be  i n such  78  an  e f f e c t .  was but  p r o p o r t i o n  n o t c o r r e l a t e d was  the  s t r o n g l y  p r e c e d i n g  expected energy  over  observed  r e s o u r c e s  a t  s u c c e s s f u l  h i g h e r  m o r t a l i t y  c o n s i s t e n t  f e e d i n g  was  d e n s i t i e s If weight  no  s i m i l a r  i n t e r p r e t e d then  t h e  a n i m a l s between  t h e a s  a  c o n t e s t  p o p u l a t i o n  do  n o t  t h e  h i g h  i n t h e  v a r i a t i o n d e n s i t y  i n v a r i a n c e that  of  and  of  eggs.  The  m a t u r i t y on  energy  t o  p l a u s i b l e  t h e  b r e e d i n g  and  v a r i a t i o n  p r i o r  i n  s i z e -  c o m p e t i t i o n  f o r  food  d e n s i t i e s ,  i n  which  r e s o u r c e s  t o  breed  breed.  The  d e n s i t y  and  between  g e n e r a l l y  p e r i o d  i n  l a b o r a t o r y  Lasenby f e e d i n g  a r e  1982),  mysids  a t  f i e l d . i n  t h e g e n e r a l  t h e  s i z e - a d j u s t e d  b r e e d i n g l e v e l  t h e s i z e - a d j u s t e d  summer  be  e x p e n d i t u r e  of  makes  (Johnston  s p r i n g  t h e observed  a t  might  sexual  However,  i n t e r f e r e n c e  d a t e ,  a c q u i s i t i o n  t o  s u f f i c i e n t  mercedis  r e f l e c t i n g  t h e s p r i n g  imply  as  t o produce  seasonal  i n N.  low  suggests  o f  s p e c u l a t i o n .  y e a r - t o - y e a r of  lack  t h i s  t o those  t h e  t h e p r o p o r t i o n  d u r i n g  n=l3)  t h e energy  which  g r a v i d  a v a i l a b i l i t y  d i v e r s i o n  i n d i v i d u a l s  obvious  on  were  t h e sampling  food  p r i o r  o f  2 ) ,  o b t a i n  r a t e s  w i t h  of  most  h i g h e r  i n d i v i d u a l s  u n s u c c e s s f u l  t h e r e  may  t h e  w h i l e  s t u d i e s  The  a t  l a y i n g  t h e  between  weight  egg  which  p<0.05,  immediately  chapter  a v a i l a b i l i t y .  t o  depended  p r e c e d i n g  ( s e e  c l u t c h  c o r r e l a t e d  through  c o r r e l a t i o n  a d j u s t e d  a v a i l a b i l i t y  accumulate  c l u t c h  females  date'(r=0.74,  r a t e s  t o  a d u l t  l a r g e l y  t h e molt  v i t e l l o g e n e s i s  food  p o s i t i v e l y  i n growth  f i r s t  of  food  sampling  s u f f i c i e n t  the  w i t h  i f t h e mysids  r e d u c t i o n is  The  v a r i a t i o n  b r e e d i n g  o f  animals food  c l u t c h i n  females  c l u t c h  s i z e  mean  c a n  be  abundance, i n egg  i n 1978 d o e s  these s i z e n o t  79  represent  a  b r e e d i n g  females  amounts  of  d e n s i t y s i z e so be  food  r u l e d  but of  simple  a n a l y s i s  that  r  t h e s m a l l e s t  to on  from  a l l  e s t i m a t e a  s u r v i v a l a l t h o u g h the  suggests customary p r e d a t o r s  mysids  sources  r a t e s  r a t e s  when  or  M u l t i p l e m o r t a l i t y  t o aquire  were  of  (Table  death  rates  of  salmon  f r y rather  f o r  (Cody  4 ) .  neonates by  was food,  f i s h  p r e d a t i o n  lower  produced, l a r g e  that  most  of  accounted  m o r t a l i t y  methods  rates  between  t h e  Thus, during data  a l t h o u g h  a b i l i t y  t o  t h e a v o i d  a p p l y . i n s t a n t a n e o u s  t o measures  t h e v a r i a t i o n f o r by  a n d , a l t h o u g h  used  i n  neonates  t h e  r e l a t e d  t h e  eggs.  eggs,  1 9 6 6 ) may  u n l e s s  t h e a v a i l a b l e  increased  were  The  on  suggests  increased  but  small  The  During  d i f f e r e n c e s  and  suggested  However,  s i z e .  1 8 ) .  s i z e .  s i z e  egg  6)  cannot a d a p t i v e  4)  egg  egg  1984),  t h e  d i f f e r e n t i a t e  g e n e r a l l y  j u v e n i l e s  than  t o  regarding food  of  r e s o l v e  were  of  low  of  Lawlor  Appendix  (Figure  t h e  a v a i l a b i l i t y  (Table  large  eggs  r e g r e s s i o n  r a t e s  a v a i l a b i l i t y  from  advantage  s p e c u l a t i o n s  from  cannot  enough  l a r g e  obvious  of  d e c r e a s e d  f i n e  m o r t a l i t y  no  with  from  i n c l u t c h  independent  s i z e  h a t c h l i n g s  p e r i o d  (see a l s o  rate  s i z e - a d j u s t e d  and  food  summer  dependence  question  t h e m o r t a l i t y c l a s s  (Brody  r e d u c t i o n  c o n s i d e r a b l y  s c a l e  of  above  s i m i l a r  inverse  t o  t h e  r e s u l t i n g  m o r t a l i t y  s i z e  An  isopod  begs  The  d i f f e r e n t l y  response  l a r g e l y  v a r i e d  q u i t e  f o r an  t h i s  be  a v a i l a b i l i t y .  a n i m a l s .  d i s c u s s e d  summer,  r a t e s  energy  t h e  would  food  p a r t i t i o n e d  p h y s i o l o g i c a l  out  s u r v i v o r s h i p  t o  1978  i s r e p o r t e d  s i g n i f i c a n c e  on  i n  r e p r o d u c t i v e  d i r e c t  e a r l y  response  spring-breeding  on a  d i r e c t  of  food  i n  t h e  t h e abundance  food  accounted  of f o r  80  up  t o  50%  of  the  v a r i a n c e  s u b s t a n t i a l  amounts  Although  t h e  mechanisms  p a t t e r n  of  b i o l o g i c a l main  r a t h e r  s i z e - s p e c i f i c  and to  as  l e v e l s N.  Changes  i n  the  from  b i r t h d u r i n g  a d u l t  females  most  c a s e s of  may  reduced  f a c t o r s  food  the  t o  the  cannot  such  as  a v a i l a b i l i t y  v a l u e s  be  of  i n  t h e  t h e  age-  p o p u l a t i o n per  food  or  which  the  c a p i t a  a v a i l a b i l i t y p r o p o r t i o n  i n  i n t o  t h e  p r e d a t i o n ,  p r o c e s s  of  s i n c e  p a r t i t i o n e d  t h e  known  p o p u l a t i o n  However,  food  t o  Temperature  reduced  s u r v i v o r s h i p .  was  1971).  lower Lower  of  p r e d a t i o n ,  v a r i a t i o n  p r o p o r t i o n  t h e  component  reach  mysid  r a t i o .  r a t e s  one  H a i r  t h e r e f o r e  egg  s p e c i f i e d ,  p r o b a b l y  f i s h  d i d not  s e a s o n a l  the  i n  f o r .  temporal  e x a c t l y were  from  1951;  c o n t r i b u t e  m o r t a l i t y  s p e c i f i c of  and  reduced  through the  importance  t h e  remains  i l l -  i n e d . The N.  e s t i m a t e s  mercedis  zooplankton (0.27  day"  1  e s t i m a t e s mean  a  summer  a d u l t  reduce  f e m a l e s ,  through  t h e  e f f e c t s  r a t e s  from  unaccounted  s e a s o n a l l y .  I s l a n d  of  j u v e n i l e s ,  observed  v a r i a t i o n  (Wilson  and  the  f a c t o r s  changed  s t r u c t u r e  r e c r u i t m e n t  by  r a t e  age  remained  r e s u l t i n g  Woodward  mercedis  m o r t a l i t y  comprised  that  l a r g e r  cannot.be  e n v i r o n m e n t a l Temporal  of  f o r  m o r t a l i t y  community a t  t o  s p e c i f i c  for  f i s h  v a r i a n c e  r e s p o n s i b l e  a g e n t s .  l e t h a l  r e s u l t  def  than  m o r t a l i t y  the  m o r t a l i t y ,  t h e  oxygen be  of  s i z e - s p e c i f i c  m o r t a l i t y  evident  i n  summer  of  a r e  i n s t a n t a n e o u s n a t a l i t y  i n  t h e  range  ( e . g . N e i l l )  f o r N.  a v a i l a b l e b i r t h  1981b).  mercedis f o r  r a t e s  commonly  a r e  other  (0.03  The  s l i g h t l y n o r t h  day"  1  )  and  found  f o r  maximum h i g h e r  temperate  a r e  m o r t a l i t y  s i m i l a r  r a t e s  c r u s t a c e a n b i r t h  than m y s i d s , t o  the  r a t e s  the but  few the  0.023-  81  0.044  day"'  that  Metamysidopsis et  a l .  the  elonqata  (1981)  death  f o r  (0.15-0.20  d a y "  6)  i n  estimated between  1  ) .  two  the  the  of  known  the  (approximately  t o t a l  ( F i g u r e  f o r  that  Toda  S i m i l a r l y , to  N.  those  intermedia  was  of  not  F i s h  r a t e s  from  t h a t  i n  the  reduce  w i t h i n  the  channel,  (November  1977).  H e r r i n g never  caught found  i n  i n  the  i n  the  they  only  one  t o  be  Moreover,  not  i n c l u d e  of the of  the  date  over  the  Temporal  between  death  the r a t e s  r a t e .  m o r t a l i t y  f i s h on  stomachs one  from was  occasion  contained  F a i l u r e  be  were  sampling  m o r t a l i t y  channel  c h a n n e l .  not  p r e d a t i o n  agreement  v i o l a t e d  w i t h i n  was  samples.  e s t i m a t i o n  was  s i n c e  m o r t a l i t y  estimates  found  agreement  c o u l d  s p e c i f i c  v a r i a t i o n  a l l m a t e r i a l  consumed  mysid  would  do  f i s h  between  S e q u e n t i a l  assumptions  a  r a t e s  expected  p r e d a t i o n  m o r t a l i t y  temporal  be  p r e d a t i o n  Crangon  of  a l l sources.  i n t e r v a l  r a t e s  Lack  p r e d a t i o n  from  (Table  m o r t a l i t y  unexpected  would  from  p r e d a t i o n  18).  day)  c o n s i d e r a b l e  l o p h o g a s t r i d  the  average  e s t i m a t e s .  p r e d a t i o n ,  and  w i t h  estimated  of  f i s h  )  f i s h  method  14  the  1  from  t o  two  of  day"  r e f e r r e d  m o r t a l i t y  One  1  comparable  which  i n  suggested  day"  r a t e s  m o r t a l i t y  s i n c e  e s t i m a t e s  v a r i a t i o n s e t s  are  t h e r e f o r e  m o r t a l i t y  Lynch  estimated  i n t e r m e d i a .  (0.019-0.10  q u a n t i t i e s .  of  The  0.10-0.15  obtained  e s t i m a t e s  e s t i m a t e s of  (1968)  Neomysis  method  and  e s t i m a t e s  whereas  of  p r e d a t o r s ,  e s t i m a t e d . point  Lynch  m o r t a l i t y  e s t i m a t e s  a l l  I  m o r t a l i t y  s e t s  component  the  the  f o r  agreement  d i f f e r e n t  than  C l u t t e r  •  estimate  lower  t o  elongata  poor  u s i n g  the  and  that  M.  g e n e r a l ,  were  and  c a l c u l a t e d  r a t e s  estimated  In  Fager  of  a t h i s  82  assumption those  s i z e  r e s u l t i n g  L i f e  would  c l a s s e s  b i a s  i s  of  mercedis  apparent  a c t u a l l y  m o r t a l i t y  consumed  o u t s i d e  e s t i m a t e s  the  of  c h a n n e l .  The  u n a s s e s s a b l e .  the  i n  p o p u l a t i o n s S i e g f r i e d  i n  et  the  Mauchline  1971;  p a t t e r n  2-3  g e n e r a t i o n s  mechanism  abundance  f o r  a l l o w  c o n d i t i o n s i n d i c a t e  i n  regimes  north  primary  and  w i t h  to  of  size-dependent "environment p a t t e r n s "  e x p l o i t of  p r o d u c t i o n  the  i n c r e a s i n g  by  Indeed, and  the  summer  m a t u r i t y , and  s t r o n g  genus.  of  growth  dependent  ( G i e s e l  and  Yesaki  p.58)  may  the  g e n e r a l l y  F r a s e r  (Takahashi 1979)  which  environmental  temperatures In  a  phenotypic  1976,  f a v o u r a b l e  phytoplankton and  Neomysis  f e c u n d i t y , p r o v i d e s  l a t i t u d e s .  ( K i s t r i t z  and  the  r a t e s  1955;  americana  at  of  are  Kinne  f e c u n d i t y ,  the  geographic  winter  s i z e  c h a r a c t e r i s t i c  temperate  macrophytes  i n  i n  1969;  h i s t o r i e s  1979),  d i s t i n c t  s i z e - a d j u s t e d seems  i t s  1981,1982).  y e a r ,  dependence  mercedis  a l .  present  Neomysis  Corey  d i f f e r e n c e s  r e p r o d u c t i v e  t h a t  et  Neomysis  (Heubach  1951;  1978),  and  of  l i f e  (Vorstman  K r u i j f  per  g e n e r a t i n g  i n N.  Toda  i n  coupled  p l a s t i c i t y  de  l i m i t  S i m i l a r  by  a l s o  e s t u a r y  southern  Pezzack  marked  temperature  m a t u r a t i o n ,  e s t u a r y ,  1964;  v a r i a t i o n i n  and  g e n e r a t i o n s  w i t h  s e a s o n a l i t y  the  i n t e g e r  1971;  (Murano  seasonal  at  are  Joaquin  1973).  B e a t t i e Burns  of  The  1979),  d i s p l a y e d  e s t u a r y  Sacramento-San  Neomysis  and  t r a i t s  R i v e r  (Holmquist  f o r  i n t e r m e d i a  h i s t o r y  F r a s e r  a_l.  r e p o r t e d  (Wigley  l i f e  the  d i s t r i b u t i o n  1973)  the  H i s t o r y  Most  may  i n f l a t e  show  R i v e r e_t a l .  i n c r e a s e s  83  in  the  water  May-August  p e r i o d  temperature.  In  year-to-year  The  set  a l l o w  of  i t s  w i t h l i f e  the  p r o d u c t i o n  the  v a r i a t i o n  c o r r e l a t e d  i n  i n d i c e s h i s t o r y  mysid  to  t y p i c a l  of  h a b i t a t .  that  c l o s e l y  Sacramento-San the  of  abundance  primary  t r a i t s e x p l o i t  the  p a r a l l e l  n o r t h  Joaquin N.  Neomysis  s t r o n g  temperate  changes  R i v e r  mercedi s  p r o d u c t i o n  which the  of  the  i n  e s t u a r y , i s  h i g h l y  (Anonymous  1978).  d i s p l a y s  would  s e a s o n a l i t y e s t u a r i e s  i n which  primary form  84  CHAPTER  2.  THE  UTILIZATION.OF  mercedis  IN  THE  ASSIMILATED  FRASER  I n t r o d u c t  L i f e  h i s t o r y  r e p r o d u c t i v e as  age  p a t t e r n  and  r e p r o d u c t i v e r e s u l t s the  of  the  by  s i z e e f f o r t ,  r a t e  then  to  that  the  and  the  and  number  a c t i n g  of  to  r  for  amount s i z e  i s  maximization  r e p r o d u c t i v e  account  maximize  i n c r e a s e  Neomysis  ESTUARY  v a r i a t i o n  r e p r o d u c t i v e  m a t u r i t y ,  f i t n e s s  i n d i v i d u a l ' s  attempts  assuming  BY  ion  at  s e l e c t i o n  i n t r i n s i c  measure,  theory  RIVER  ENERGY  young  of  are  the  f i t n e s s .  a p p r o p r i a t e  e q u i v a l e n t  such  t i m i n g  i n d i v i d u a l an  i s  t r a i t s  and  of  i n  to  I f  f i t n e s s m a x i m i z i n g  value  oo  V(x)  =  [ e x p ( r - x ) / l ( x ) ]  I  [ e x p ( - r • y ) • 1 ( y ) • b ( y ) ]  y=x  at  every  This  age  leads  f e c u n d i t y  Two  means  to  of  the  of  i n t e r e s t : which  Numerous  authors  G i e s e l  the  i n  (Pianka  and  (1)  1976;  i t have  f i r s t what  1974;  Parker  r a i s e d the  e f f o r t  a d d r e s s e d 1976,  the  Yodzis the  and  between the  1981).  a g e - s p e c i f i c  schedules,  determining  are  of  t r a d e - o f f s  advantageous  Stearns  a l .  ( l ( x ) )  of  e f f o r t s  both  et  inter-dependence  importance  r e p r o d u c t i v e i s  Taylor  s u r v i v o r s h i p  t a c t i c s  circumstances  see  and  q u e s t i o n s ,  1974;  to  r e p r o d u c t i v e  r e p r o d u c t i v e  become  d i r e c t l y  (b(x))  consequence, f u t u r e  (Schaffer  as  a  present  " o p t i m a l "  and  set  of  1975). by  F i s h e r  (1930),  then  p h y s i o l o g i c a l mechanisms  i s to  v a r i e d ? vary  l a s t  1977;  and  under  r e p r o d u c t i v e  q u e s t i o n  Calow  (2)  1977)  ( f o r to  by  what  e f f o r t ? reviews  generate  a  85  m o r e - o r - l e s s T i n k l e  agreed  1975;  r e p r o d u c t i v e (1)  or  a d u l t  u n p r e d i c t a b l e  or  longer (3)  (4)  l i f e ,  when  I  should  of  s i z e  t o  energy  m e r c e d i s -. o f  r e p r o d u c t i o n  1980).  I  v a r i a b l e s components  of  of of  t h e  r e p r o d u c t i v e  r e l a t i o n s h i p s  t o  h i g h ,  r e p r o d u c t i v e  favoured  which  v a r i a b l e , e f f o r t  or  e a r l y  a r e h i g h ,  i n  v a r i a b l e  r e p r o d u c t i v e  when  m o r t a l i t y  m o r t a l i t y  e f f o r t  and  a d u l t  t h e age should  t h e a d u l t  r a t e  exceeds  p o p u l a t i o n s  e f f o r t  a t  be  m o r t a l i t y i t e r o p a r i t y  m o r t a l i t y ,  m a t u r i t y  should  concentrated  be  e a r l y  i n  i n c r e a s e d .  t e s t  t h e  above  a l l o c a t i o n  i n  Reproductive  and  T i n k l e  t h e  may  estimate  be  was budget  water  that  1975;  see on  determine  t h e mechanisms then  from  B e l l  environmental  ( i . e . ,  budgets  t h e  devoted  a l s o  that  and  mysid  as  was  r a t e s  v a r i e d ) ,  energy  examining  measured  dependence  budget  by  b r a c k i s h  e f f o r t  p h y s i o l o g i c a l  e f f o r t  t h e  energy  measured  energy  p r e d i c t i o n s  t o t a l  ( H i r s h f i e l d  t h e  decreased  1983a),  be  t h e animal's  f i r s t  reduce  f e c u n d i t y ,  a r e  r a t e s  w i l l  through  i n decreased  j u v e n i l e  j u v e n i l e  brood  i n c r e a s e d  (Stearns  t h e  f u t u r e  which  r e s u l t  r e p r o d u c t i v e  p r o p o r t i o n  which  l i f e  attempted  Neomysis  and  a l l o c a t i o n  e f f o r t  e i t h e r  m o r t a l i t y  should  i n expanding  p a t t e r n s  r a t e s  favour  s e m e l p a r i t y  and  ( H i r s h f i e l d  t h e  r e p r o d u c t i v e  d e c r e a s e d  j u v e n i l e  a d u l t  decreased,  to  w i l l  exceeds  favoured  regarding  e f f o r t ,  m o r t a l i t y  whereas  rate  i n c u r r e n t  through  u n p r e d i c t a b l e  and  p r e d i c t i o n s  1976)  r e p r o d u c t i v e  (2)  of  e f f o r t :  s u r v i v o r s h i p  l i f e  s e t  Stearns  i n c r e a s e s  f u t u r e  upon  t h e through  a p p l i e d  f i e l d  t h e  c o n d i t i o n s  86  for  p o p u l a t i o n s  S u c c e s s i v e  g e n e r a t i o n s  experience (chapter  very  has  r a t e s  w h i l e  a d u l t  P o p u l a t i o n  food  g e n e r a t i o n  low  g e n e r a t i o n s  Molt ing  time  and  growth  s e r i e s  f i e l d  growth  r a t e s  o b t a i n e d Newly  of  m o r t a l i t y  l a b o r a t o r y  of  and  food  a v a i l a b i l i t y  t h e  w i t h  l o w e r t h e  summer  a  g e n e r a t i o n s . h i g h  h i g h  t h e above  t o  i n t h e j u v e n i l e  when  i s  (S1)  summer  a r e expected  and  than  summer a t  regimes  breeds  t h e p o p u l a t i o n  second  t h e  growing  g e n e r a t i o n  d e n s i t y  and  g e n e r a t i o n  (S2)  vary  among  t h e  p r e d i c t i o n s .  M a t e r i a l s  by  e s t i m a t e s data  r a t e s  and  r e a r i n g  hatched  c o n t a i n e r s  which  R i v e r  Growth  R e l i a b l e  s p e c i f i c  demographic  t r u e  f i r s t  e s t u a r y .  F r a s e r  i s  i s s t a t i o n a r y  Methods  t h e  a r e  p a t t e r n s  i n accordance  and  R i v e r  t h a t  t h e  when  Reproductive  i n  g e n e r a t i o n  matures,  when  t h e p o p u l a t i o n  resources  breeds.  a r e low  d e c r e a s i n g  and  r a t e s  converse  (W)  mysid  o v e r w i n t e r i n g  d e n s i t i e s  food  t h e  i n t h e F r a s e r  environmental  m o r t a l i t y  t h e  o v e r w i n t e r i n g  breeds,  The  I s l a n d  of  d i f f e r e n t  1 ) .  s p r i n g  and  a t Woodward  250  hatched  Artemia  depending  on  of  s a l i n a  temperature.  1 ) .  be  water,  and  n a u p l i i  u n t i l i n  300  were a t  I  of  ml  age  were  p l a s t i c  excess of  i n  o c c u r r e d .  c l e a r  water  s i z e -  mysids  h a t c h i n g  f e d t o  and  i n  t h e  determined  known  i n t e r v a l s  c o n t a i n e r s  from  v a r i a t i o n  i n d i v i d u a l  I n d i v i d u a l s females  o b t a i n e d  T h e r e f o r e from  i s o l a t e d  The  not  temporal  f r e q u e n c i e s  g r a v i d were  ml  of  (chapter  experiments.  mysids  w i t h  because  molt  h o l d i n g  c o u l d  on  newly  2-3  days,  were  changed  87  at  l e a s t  weekly;  changes.  F a e c a l  Measurements 10  p p t ,  1  s t a b l e were  P h o t o p e r i o d s a p p r o p r i a t e 15°C;  12  and  by  h  a t  reduced The  t h i s  s m a l l  hatched  ±  the 10°C I  i t became  a n i m a l s  was  determined  uropod  on  the  l e n g t h  The  s i z e  the  the a t  uropod  which  i n d i v i d u a l s  were  of  and  I  o c c u r r e d  i n j u r i n g  themselves  a t  (16  s a l i n i t i e s  aged n a t u r a l  h  a t  of  g e n e r a l l y s a l i n i t y  w e l l w a t e r . d a y l e n g t h s  20°C;  on  of  t h e  16  h  a t  measure  of  t h e  i n t e r m o l t  l e n g t h  the  i n t e r m o l t molt  weight  w i t h  w e i g h i n g  t o  f o r p e r i o d s m o l t i n g  and  a t  up  was  n e a r e s t t o  280  some  of  the  t h e  animal  S u c c e s s i v e  and  i t s  m o l t i n g ,  molt u n l i k e  1973b).  determined water, jug.  days,  e s p e c i a l l y  d i s t u r b e d .  f o r  (Mauchline  d i s t i l l e d  the  of  p e r i o d .  growth  newly  o c c a s i o n a l l y .  s i z e  o n l y  t h e  l e n g t h  animal  changed  of  m o l t s  I  "daybreak".  m o l t s  t h e  d a i l y .  o v e r n i g h t ,  a f t e r  missed  of  twice  m o l t s  t h e i r  both  the  o c c u r r e d  immediately  ingest  t h e  f o r m o l t s  m o l t i n g  measurements  when  d a i l y .  a p p r o p r i a t e  t h e  undoubtedly  r i n s i n g  r e a r e d  m o r t a l i t y  most  shows  m o l t ,  60°C,  t o  o f f  were  w i t h  c o n t a i n e r s  i s a  uropod  of  between  a t 5°C).  the  of  dependence  measuring o v e r n i g h t  from  which  the  that  S o l u t i o n s  a l s o  beginn i n g  c o n f i r m e d body  that  a t  Temperatures  seawater  that  may  m o l t ,  of  and  t r a n s p a r e n c y  meant  Growth  measurements  20°C  e x a m i n a t i o n s  and  Mysids  t h e  15,  10,  h  d a i l y  r e q u i r e d  p i p e t t e d  ;  8  as  were  temperature  and  up  prey  corresponded  examined  s i z e  topped  r e a r i n g  a n i m a l s .  at  5,  0.5°C.  apparent  t o  t h e  dead  d i l u t i n g  I n i t i a l l y When  a t  were  f r e s h w a t e r .  r o u g h l y t o  and  made  w i t h i n  made  l e v e l s  p e l l e t s  were  p p t ,  t o  water  by  d r y i n g A l t h o u g h  s u b s t a n t i a l  from  A c c o r d i n g l y  a n i m a l s i t  was  88  necessary  t o  on  f i e l d  c o l l e c t e d  the  growth  e f f e c t s the  of  using  p r i o r  h i s t o r y  h e l d  f i e l d  the  i n  Female  mysids  The  determined  the  determined mature  the  female  1971;  w i t h  i n  M a u c h l i n e  marsupium i s o l a t e d  Energy  molt  n i g h t  day  of  temperature  t o  f o r  c a r r y i n g  g r a v i d  the at  females  by  which  was  the  uropod  l e n g t h s  w i l d  a n i m a l s  g r a v i d  females  females w i t h  15,  whose  I  1939;  p.43).  Eggs  20°C  o f t e n  by  p a i r i n g  o v a r i e s not  were  d i r e c t l y  a  few and  by  when  minutes  of  T h e i l a c k e r  e x t r u d e d  even  I  o c c u r r e d  C l u t t e r were  u s u a l l y  h a t c h e d .  d i d  w i t h i n  t h e r e f o r e  molt  are  f e r t i z a t i o n  o c c u r s  m o l t ,  the  and  (Mauchline  i s  e n l a r g i n g  body.  that  embryos  young  10,  (Nair  the  the  the  produced  p e r i o d ,  times  C o p u l a t i o n  mysids  a  of  that  assumed  1980,  w i t h i n  w h i l e  t r a n s p a r e n t  but  minimized  w e i g h t ,  from  determine  n o t e d .  development  the  i n  o b t a i n e d  broods  i n t e r v a l  m o l t e d . molt  of  I  r e a r i n g  e s t i m a t e d  a l s o  m a t u r i n g  the  Growth  r e l a t i o n  development  c o p u l a t i o n ,  female  matching  was  not  egg  same  through  observe the  egg  males  v i s i b l e  the  to  a n i m a l s .  was  i n t e r m o l t by  o c c u r r i n g  do  order  ( o l d e r )  number  l a b o r a t o r y  measurements  l a r g e r by  i n  w i t h  age  t e m p e r a t u r e s .  The  data  unknown  s i z e - w e i g h t  the  1973b).  the  rate  of  i n t e r e s t ,  1 ) .  growth  a n i m a l s  of  of  (chapter  the  r a t e s  ambient  v a r i a b l e  supplement  i n t o  the  u n f e r t i l i z e d  f e m a l e s .  Content  The determined  energy from  Phi 1 1 i p s o n - t y p e  c o n t e n t the  of  somatic  combustion  microbomb  of  t i s s u e ,  known  c a l o r i m e t e r .  eggs,  amounts The  of  and  m o l t s  m a t e r i a l  m a t e r i a l  was  were i n  a  d r i e d  89  as  d e s c r i b e d  and  p e s t l e ,  which  were  e_t_ . a l . had  s t o r e d  e f f e c t  benzoic  on  c o r r e c t i o n s  c u r r e n t .  Oxygen  Uptake  Oxygen  by  the  average  uptake  uptake  as  uptake  the of  of  c l o s e d r o u t i n e  measurement  r e t a r d  o x i d a t i o n .  storage  J-mg" )  1  f o r  was  was  t o  a f t e r  every  a c i d  formation  l a r g e l y  used was  that  as  a  measure  w i t h  oxygen  by  c l o s e d  b o t t l e  very  p e r i o d  and  t o vary  s l i g h t  above seems  i n m y s i d s .  c a n be  w i t h  chosen  6  oxygen  f i r i n g  wire t h e  metabolic  c l o s e d  b o t t l e  and Roff  (1976)  some  o f The  oxygen i n t o  i n  t h e  t h e  oxygen  throughout  shown  t h e  oxygen  c o n c e n t r a t i o n  b u t  N e v e r t h e l e s s  t o t h e  c o n t a i n e r  t o a l l o w  or  animals  p p t oxygen.  a p p r o p r i a t e The  c o m b u s t i o n s .  changes  have  a t  c a l i b r a t e d  e l e v a t e d  d e c l i n e s  (1980)  was  measurements.  t h e  p o s s i b l e  temperatures  d i s c u s s e d  newly-introduced  and Lasenby  technique  metabolism  of  S c h i n d l e r  r o u t i n e a  b o t t l e  weight  a d j u s t i n g  Foulds  (1969)  c o n c e n t r a t i o n  r e l i c t a  of  using  d e s c r i b e d Kamler  by  mortar  r e - d r i e d  2-3  e l i m i n a t e d  measured  (1980).  were  a  d r y  low  (26.462  d e t e r m i n a t i o n  was  a t  c a l o r i m e t e r  a r e t h e i n c o r p o r a t i o n  M y s i s  1 0 - 2 0 mg  The  Sandemann  v a r i a t i o n  t o  t h e d i s t u r b e d  t h e  experiment.  of  u s e .  a s s o c i a t e d  o f  p e l l e t s  extended  made  w i t h  i n t o  before  e_t a _ l .  consumption  powder  p e l l e t s  were  o b j e c t i o n s  f i n e  The  s i m i l a r  Gaudy  t o a  v a l u e s .  consumption  problems  c h i e f  the  c a l o r i c  uptake  Oxygen  technique  that  t h e l a t t e r  f i r i n g  r a t e .  ground  -10°C  found  a c i d  combustion;  and  a t  immediately  w i t h  1,  and compressed  (1971)  no  60°C  No  i n chapter  s i z e  t h e organism  e s t i m a t i o n and  t h e  scope  f o r  90  a c t i v i t y , the  i n c o r p o r a t i n g  a c c u r a c y  the  i n i t i a l ,  l e n g t h  of  induce  a  always  response.  f i n a l  g r e a t e r  to  and span  20°C the  a n i m a l s They  were  a  by  s e v e r a l few  degrees  and  a t  at  5  t e s t  i n  i n  at  The  the  a  of  s t a b i l i z e d  w i t h i n  2  under  c l e a n e d , The  d u r a t i o n  c y c l e s . the  ground  i r r e g u l a r  was  B o t t l e  animal  g l a s s  t o  p a t t e r n  swim of  10  and  (30-300  oxygen  may  that  N.  mercedis  experiments  1  of  50  mm  were  were The  d i d  b e i n g  of  were  f o r  a  l a r g e  w i t h  1979.  t o  t e s t  a  p e r i o d  not  exceed  temperature were  i n  N.  u s u a l l y Simmons mercedis  change. e n c l o s e d  p e r i o d  i n  of  d i e l  enough  t y p i c a l  The  of  used.  p o t e n t i a l  a l t e r n a t i n g  over  Animals  r a t e s  10,  f r e s h w a t e r  s p r i n g  n a t u r a l  consumption  7,  mysids.  change  before  any  5,  a c c l i m a t e d  to  b o t t l e s  ml)  the  e a r l y  of  and  temperature  a n i m a l s  i n c l u d e  p p t ,  by  were  s i m i l a r  n o r m a l l y . swimming  s t r e s s e s  i n  and  the  days  stoppered t o  the may  t e n s i o n s  p p t ,  w i n t e r  i n d i v i d u a l  chosen  s i z e s  of  4-5  that  cases  of  my  of  event  oxygen  environment.  showed  most  e f f e c t s  any  temperatures  s i m i l a r  (1975)  days  r e d u c i n g  e x t e n d i n g  i n  showed  temperature  rate  f o r  The  by  v a r i e t y  (.1973)  r a i s i n g  K n i g h t  In  a  above  10°C  a n i m a l ' s  c o n d i t i o n s  and  encountered  rate  day,  reduced  nominal  l a t e  or  w i t h o u t  l e v e l .  s a l i n i t i e s  s e q u e n t i a l l y  per  where  that  made  c o l l e c t e d  be  p e r i o d  Jawed  n o r m a l l y  days.  f l u c t u a t i o n s h e l d  at  range  h e l d  c o n d i t i o n s of  and  were  can  c o n c e n t r a t i o n s  than  were  rhythms,  d e t e r m i n a t i o n .  consumption  oxygen  Measurements 15,  uptake  c o n d i t i o n s  i t s oxygen  much  l e v e l  measurement  n a t u r a l  10°C;  endogenous  oxygen  oxygen  the  s i m i l a r  r e g u l a t e s at  the  h i g h  approximate  Hg  of  any  24±2  h.  a c t i v i t y  t o  b e h a v i o r r e s t i n g  a c i d -  p e r m i t was on  an the  91  bottom.  R e s t i n g  c u r r e n t s a l s o  were  used  s e v e r a l and  more  1980,  The  p r i o r  mysids  a n i m a l s  p r e c i s e  uptake showed  per  mysid  samples  v a r y i n g  p a r t i a l  oxygen  e l e c t r o d e s  PMH-71  a c i d - b a s e  e l e c t r o d e  was  temperature i n v e r t e d s y r i n g e i n j e c t e d The  known  a c r o s s was  temperature  found  by  by  mysid  the  between  a n a l y z e r  times the the  the  a  and  and  sample  w i t h  E5046)  c o u p l e d  a  t e s t  the  930 c e l l  The  o b t a i n  and  Kukina  ran t o  to  be  s e v e r a l c o n f i r m  to  water the  mean  of  oxygen  sample  the  by  the  of  20°C.  c o n t r o l  sample  drawing were  oxygen  i n  was a  s l o w l y t e n s i o n . a i r  a l l b o t t l e s  Oxygen  The  b o t t l e  s a t u r a t e d  d i f f e r e n c e 3  module.  subsamples  volumes  Radiometer  to  removed  water  at  a  c o o l e d  determine  The  p o l a r o g r a p h i c  to  c l o s e d  subsamples  p r e s s u r e .  and  PMA  a g a i n s t  from  using  r a t e s .  R e p l i c a t e  e l e c t r o d e  e s t i m a t e d  I  measured  b o t t l e .  d i s t i l l e d  range,  were  ml  s i z e  t o  m i r a b i 1 i s  mysids  water. 2  c r o p  p o s s i b l e  s i z e  M1  70  the  d a r k .  Kuz'micheva  broad  s i m i l a r  by  c a l i b r a t e d  w e i g h i n g was  i n  a  n a u p l i i  i n  a n i m a l s  Neomysis  over  1976;  n e c e s s i t a t e d  s m a l l e s t  of  the  (Radiometer  through  e l e c t r o d e  of  the  T h i s  A l t h o u g h  of  c i r c u l a t i n g  s e v e r a l up  l a r g e s t  p r e s s u r e s  mounted by  the  r a t e  number  independence  Oxygen  span  the  d e n s i t y  prey  i n  w e i g h t ) .  uptake  had  are  Roff  Artemia  done  mg  f o r  fed  and  which  and  were  to  r e s p i r a t o r y  appendages  were  chosen dry  as  (Foulds  experiments  measurements.  the  i n a c t i v e  t h o r a c i c  mysids  the  b o t t l e  of  w i t h  not  swimming  The  to  were  independent  d e n s i t y  the  A l l measurements  s e v e r a l  the  were  a c t i v e  (0.024-7.136  (1974)  by  p.140).  hours  f o r e g u t .  range  generated  i n  Mauchline  animals  at were  consumption  oxygen  b o t t l e s .  l e v e l s Animals  92  were  sexed  and  r a t e s  were  molted  d u r i n g  weighed  c o n v e r t e d  i n c u b a t i o n  were  t o  were  p e r i o d ,  0.3°C. used  i n  0  Mg  found  t h e  Average  2  were t o  mean  Oxygen  - a n i m a l "  1  > h " ' .  a n a l y z e d  d i f f e r e n c e over  consumption A n i m a l s  which  s e p a r a t e l y .  f l u c t u a t e  t e m p e r a t u r e s  i n r e g r e s s i o n  1.  c h a p t e r  t h e measurements  Temperatures  being  a s  s l i g h t l y  from t h e  over  t h e  t h e nominal 24  hour  l e v e l  i n t e r v a l  a n a l y s e s .  R e s u l t s  Growth  The  time  p a t t e r n  mercedis  was  s e v e r a l  d i s t i n c t  changed the 3  roughly  s t r a i g h t  c o u l d  c o n t i n u o u s  a t  p r o c e s s  1959).  Because  of  l i n e a r  change  i n  i n c r e a s e growth  i n body of  newly  c o n s i d e r a b l y l e n g t h . a n i m a l s  as  T h i s t o  m a i n t a i n e d  w i t h i n a t  be  l e n g t h At  r e l e a s e d  young  t h e  or  t h e  a t t a i n e d be  handle animal  slow  r e l a t e d  neared  a  s e r i e s  t o  of  t o  and  sexual  r a t e  of t h e  i n c r e a s e d mm  t h e a b i l i t y  The  t h e  10°C,  but  a  Knowles  l e n g t h ,  0.7-0.9  or  p r o b a b l y  about  i n i t i a l l y  2  changed  e x p o n e n t i a l  below  Thus, of  l e n g t h was  i n  l e n g t h  2 2 ) .  ( C a r l i s l e  s i z e s  p r e y .  by  an  t e m p e r a t u r e s  may  (Figure  weight  i m p l i e s  was  o c c u r r i n g  a d d i t i o n  of  Neomysis  t h e uropod  uropod  c r u s t a c e a n s  w e i g h t .  capture  which  approximated  t h e r e l a t i o n s h i p  i n c r e a s e  growth  r a t e  weight  i n other  uropod  of  c o n s t a n t  m o l t i n g ,  as  f o r i n d i v i d u a l  w i t h  each  A l t h o u g h  t h e a n i m a l s  u n t i l  a  w e l l  segments.  d i s c o n t i n u o u s l y ,  l e n g t h s  r e c t i l i n e a r ,  i n time  curve l i n e  uropod  phases  l i n e a r l y  growth  of  higher m a t u r i t y ,  uropod of  small  r a t e when  was t h e  93 3  T  10 C  2 ••  100  200  300  Age (days) 3 T  E E 2 --  c  CD "O O  1 --  a o  50  100  150  Age (days) 3 T 20 C  2 --  1 --  •+-  50  100  150  Age (days) F i g u r e  23. R e p r e s e n t a t i v e growth c u r v e s for Neomysis m e r c e d i s : t h r e e s e t s of s i b l i n g s at (a) 1 0 ° C , Tb) 1 5 ° C , and (c) 20°C . Note that the s i z e of i n d i v i d u a l mysids i n c r e a s e s l i n e a r l y i n time over much of the a n i m a l ' s l i f e .  94  rate of  of  an  change  animal  higher  was  or  s t r a i g h t  c o n s t a n t  over  absent  was  temperature. F i g u r e  averaging  were  r a t e s  of  s i z e  d e s c r i b e d  growth  r a t e  the  and no  r e a c h i n g  broods  i n  h a t c h i n g  i n  or  between  c u r v i l i n e a r the  over  on  the  r e l a t i o n s h i p  marked  small  At was  by  two  the  i n  the  r a t e s ,  S i m i l a r l y  and  may  a n i m a l s  l a b o r a t o r y  i n c r e a s e d  (5-20°C) ( q u a d r a t i c  growth  that d i d  whose  s i z e  of not at the  p o s s i b l e  have  obscured  the  a r e  expected  t o  d i f f e r e n c e s at  hatched  a  were  d i f f e r e n t  a n i m a l s  have  l i n e a r l y  i n  to  s i z e s  reared  examined  s i b l i n g s  However,  major  d i d , however,  high  mean  rate  a n i m a l s  which  no  was  magnitude  neonate  used  given  W i t h i n - c l u t c h  n=l9). of  a  f o r  the  growth  those  length)  of  i n  at  Consequently  f e m a l e s .  range  growth  which  range  Anova)  but f o r  (CV)  c l u t c h e s .  p>0.05,  Temperature  r a t e s ,  f i t t o  1 ) ,  r a t e s w i l d  some  s i m i l a r  s i z e  w e i g h t .  growth  growth  was  (uropod  s i z e  the  temperature  and  v a r i a t i o n  d i f f e r e n t  (r=0.27,  measure  t e m p e r a t u r e . on  i n  (chapter w i t h  of  (p>0.1,  r a t e s  known  neonate  s a l i n i t i e s  38%  of  growth  s i z e of  c o e f f i c i e n t  d i f f e r e n c e s  e x p o n e n t i a l  A  be  w e l l  phase  i n  i n a t  the  improve  c o u l d  r a t e  v a r i a t i o n  i m p r e c i s i o n  e f f e c t  growth  r a t e  2 3 ) .  growth  W i t h i n - c l u t c h  r e l a t i v e  same  and  low  (Figure  r a t e s  was  found  i n i t i a l  i t s l i f e  growth  growth  h a t c h i n g  be  the  of  the  i n  s i g n i f i c a n t l y  e f f e c t s  much  Thus  v a r i a t i o n  the  v a r i a t i o n  w i t h  d e c r e a s e d .  c o n s i d e r a b l e  2 3 ) ,  15%  there  vary  l e n g t h  l i n e s .  There  the  uropod  t e m p e r a t u r e s  reduced  (see  of  a t  the  s i g n i f i c a n t  w i t h  ( F i g u r e  temperature)  i n c r e a s i n g 2 4 ) .  A  d i d  not  d a t a .  r e d u c t i o n  i n  the  growth  r a t e  a p p r o x i m a t e l y  Figure  24. The d e p e n d e n c e o f t h e g r o w t h r a t e s of N e o m y s i s m e r c e d i s on t e m p e r a t u r e . ( a ) = immatures, (b) = mature f e m a l e s , (c) = mature m a l e s .  96  c o i n c i d e d  w i t h  temperature mature for  t h e  m a t u r i t y . were  was  males  l e s s  (Figure  24a) or mature  males  growth  rate  was  u s u a l l y  p r o d u c t i o n . mature  The  males  temperatures d i d  near  n o t mature  dependence  Table  7.  o f  a t  females  f e e r  a p p l i e d  much  c o r r e c t l y newly  r a t e s  i c i e n t s of en growth r rature f o r e male Neom  o f  i s g i v e n  hatched  data  temperature  peaks  i n  t h e  s t a r t i n g  a n i m a l s .  The  24b) animals i n  p r e c e e d i n g  egg  z e r o  f o r both  growth  I s l a n d  t h i s .  +++-  1  a t  p o p u l a t i o n  The  temperature  7.  data  r  0.00013 0.00030 0.00028  t h e  i n t e r v a l s  i n  of mature  peaks  2  0.59 0.66 0.22  f o r Woodward  abundance  from  SE  summarized  i n  c a l c u l a t e d  w i t h  r e d u c t i o n  r a t e s  i n Table  +-  0.00238 0.00265 0.00147  r a t e  Ancova)  t h e l i n e a r r e l a t i o n y = a + b a t e (mm u r o p o d l e n g t h / d a y ) a n d immature, mature female, and ysis m e r c e d i s .  b  growth  p r e d i c t e d  below  - 1  t h e  (Figure  The  t o  o f  immature  growth  temperatures  t o t h e f i e l d  o c c u r r e n c e  of  and  mm-day  s l o p e  t h e molt  e x t r a p o l a t e d  -0.0088 -0.0208 -0.0117  t h e  a t  0.4  females  e i t h e r  r a t e -  a n i m a l s  (p<0.05,  2 4 c ) .  dependence  a  immatures mature males mature females  The  i n t h e Woodward  c a t e g o r y  When  ( F i g u r e  of  t h e growth  about  8°C; a n i m a l s  t h e growth  C o e f betw temp matu  by  o f mature those  o f  immature  females  e v i d e n t  temperature  and  f o r  Ancova).  r a t e s than  s l o p e s  lowered  f o r mature  t h e growth  c o n s i d e r a b l y  were  (p<0.05,  lowered  that  The  i d e n t i c a l  b u t t h e r a t e s  mature  r e s u l t  were  r e l a t i o n s  males,  r e l a t i o n the  s e x u a l  Table  T  n 142 29 24  7  were  I s l a n d ,  t h e  females  were  abundance  o f  f o r t h e S 1 , S 2 ,  97  and  W  g e n e r a t i o n s  were  r e s p e c t i v e l y  w h i l e  those  (Figure  were  57  5)  suggested  t h a t  p o p u l a t i o n fed  the  which  l a b o r a t o r y M u l t i p l e  growth  i n  m u l t i p l e  b r o o d i n g , produced  p h y s i o l o g i c a l l y  43  to  from  days,  r a t e s  46  of  the  and  was  and  257  days  s i z e - f r e q e n c y  185+  t h a t  breed  days,  days.  segment s i m i l a r  T h i s  r e s u l t  the  f i e l d  of  to  data  those  of  w e l l -  a n i m a l s .  c l u t c h e s  h e l d  were  days,  reared  days,  e s t i m a t e d  managed  females  58  were  produced  the  l a b o r a t o r y  two  c l u t c h e s  by  a  capable  about  ( F i g u r e  were  s i n g l e  of  by  21%  25).  l a i d  of  In  but  mature  most  up  female.  the  to  N.  cases 5  of  broods  mercedis  i s  i t e r o p a r i t y .  Molt i n g  M o l t i n g of  the  m o l t i n g  d o r s a l l y , was  by  plane  C o n v u l s i o n s animal normally At p e r i o d a  males  as  5  g i v e n  a n t e r i o r  the  w i t h  s u g g e s t i o n  i n  10°C  s i z e  the  d a t a .  l i n e a r l y c a t e g o r y ;  of  w i t h  of  the or  The  the the  molt  body  3  of  p o r t i o n s  molt  s p l i t  the  a n i m a l ,  i n  the  on  the  seconds animal  and  dorso-  s u b s t r a t e . u n t i l  was  the  swimming  molt. d u r a t i o n the  of  animal  i n t e r m o l t frequency  i n c r e a s i n g  f u n c t i o n a l  of  r e s t e d  exuvium.  reduced  The  observed The  r e g i o n  about  s i z e  I  o c c a s i o n s .  swam  a f t e r  the  but  of  temperature,  s l i g h t the  two  i n t e r v a l s  minutes  n i g h t  on  animal  at  of  at  f l e x i n g  the  i n c r e a s e d  i n c r e a s e d each  v i g o u r o u s  f r e e  w i t h i n a  from  o c c u r r e d  was  o c c u r r e d  process  backward  removed  v e n t r a l  was  g e n e r a l l y  (Table  p e r i o d s  i n t e r m o l t 8 ) .  There  f o r  small  ( i n t e r m o l t  temperature  r e g r e s s i o n s  the  of  ( F i g u r e the  molt  p e r i o d " 26a) r a t e  1  )  f o r are  98  80  i  60 "  1 >» o  40-  CT  0) i_  Li.  20 -  0  1  1  1—  i  1  2  3  1  1—•  4  i  '  1 —  5  Number of C l u t c h e s  F i g u r e 25. The f r e q u e n c y o f c l u t c h e s p r o d u c e d by m a t u r e Neomysis m e r c e d i s h e l d under l a b o r a t o r y c o n d i t i o n s .  99  Table  8.  Average  i n t e r m o l t  Neomysis 15,  (mm)  s i z e  5  0 . 4 - 0 .6 0 . 6 - 0 .8 0 . 8 - 1 .0 1 . 0 - 1 .2 1 . 2 - 1 .4 1.4-1 .6 1 . 6 - 1 .8 1 . 8 - 2 .0 2.0-2 2.2-2 2.4-2 2.6-2  19. 18. 22. 18. 24. 28. 24.  .4 .6 .8  i n  10  3 + -1 . 5 0 + - 0 .9 0 + - 2 .0 2 + -.1 .8 0 + - 3 .0 5 + - 4 .0 7 + - 2 .9  Table and  animal  The  [8]  normal  7.8+-0.4 7.5+-0.5 8.2+-0.2 9.2+-0.4 10.7+-0.5  The  26b)  r a t e  development  r a t e  t h e  10,  C  20  C  2 . 8 + - 0 .2 3. 3 + -0.1 3. 9 + - 0 .1 4 . 5 + - 0 .2 4 . 6 + - 0 .2 5 . 0 + - 0 .2  - 0 .3 - 0 .2 - 0 .2 - 0 .2 - 0 .2 - 0 .2 - 0 .2 - 0 .2 - 0 .2  r e l a t i o n  5 . 5 + - 0 .3 6 . 1 + - 0 .3 6 . 2 + - 0 .3 6 . 7 + - 0 .3  molt  between  dependent  t h e constant frequency  -0.00782•W" '  p e r i o d s  d e c l i n e d  (development  ( F i g u r e  m a r g i n a l l y  2 6 c ) . b e t t e r  a g a i n s t  0.95  i n p r e d i c t i v e  e s p e c i a l l y  s i n c e  the  d a y .  nearest  f o r  5,  8 . 7 + - 0 .5  s t r o n g l y  were  i n t e r v a l s  p e r i o d s  d i f f e r e n c e  of  0  =  development  p o l y n o m i a l  SE)  16.6+-0.6 18.5+-3.5  were  t h e  3. 7 + 4+ 3 + 9+ 3 + 8+ 0 + 6+ 7. 8+  4. 5. 5. 6. 6. 7. 7.  •10.7 + - 0 . 2 11.2+-0.3 11.5+-0.3 12.9+-0.4 13.8+-0.7  slopes  as  of  i n t e r m o l t  a  15  6.5+-0.3 7.0+-0.3 7.3+-0.3 8.8+-0.3 9.6+-0.4 10.3+-0.3 11.2+-0.3 11.8+-0.3 12.8+-0.3 13.0+-0.4 15.1+-0.6 16.7+-0.8  development  temperature  1 a t  on  terms on  t h e  t h e  o f  s i z e  Table  body  molt of 9.  s i z e  and  than  t h e  same  s i z e .  Egg  temperatures  w i t h  t h e  l i n e a r l y  w i t h  becomes  molt  Egg  (+-  s i z e s  C females  temperature  ( F i g u r e  i n days  d i f f e r e n t  males  9.  dependence  temperature  of  C.  C  28  frequency  gave  20  .2  given  the  and  p e r i o d  mercedis  t h e The  7 0  were  0.00971•W~  c o n s i d e r a b l y  f o r animals a t  p e r i o d A  )  l i n e a r  g r e a t e r  t h e  f o r  t h e  r e l a t i o n ) , t h e  p e r i o d s range  2  ' "•T  ( q u a d r a t i c )  2  between  t h e  0  i n c r e a s i n g  (r =0.96  development of  - 1  c u r v i l i n e a r  f o r t h e a b i l i t y  of  higher  f i t  maxima  +  two  were of  i s only  f u n c t i o n q u a d r a t i c  however  t h e  n e g l i g i b l e , recorded  i n c u b a t i o n  t o  p e r i o d s  1 00  Table  9.  opod  F u n c t i o n a l r e g r e s s i o n s o f mean m o l t frequency 1 (day" ) a g a i n s t temperature f o r d i f f e r e n t s i z e c l a s s e s of Neomysis m e r c e d i s .  (mm)  s i z e  a  b  0.4-0.6 0.6-0.8  -0.0625 -0.0303  0.8-1.0 1.0-1.2  -0.0170 0.0007  1.2-1.4 1.4-1.6 1.6-1,8 1.8-2.0 2.0-2.2  -0.0181 -0.0160 -0.0064 0.0066 -0.0060 -0.0021  2.2-2.4  observed at  (27-38  20°C)  were  development (as  i n  were  temperatures The ( F i g u r e s males  and  d r y 27a  that  below  g r e a t e r  The  i n s l o p e  of  t h e l a r g e  0.99 0.99 0.99 0.99 0.99  a t  1.3 o f  o f  then  f a i l  t o d e v e l o p , n a t u r a l  days  I f egg weight  t h e r a t i o  p o s s i b l e  r a t e  10-11  egg  egg  Thus  t h e observed  eggs  t h e  of  t i m e s .  i n c u b a t i o n  5 5 5 5 5 5 5 4 4 5  v a l u e s .  power  1981b),  The  i n  15°C,a n d  t h e minimum  t h e range  f o r much  of  t h e  m a r s u p i a l  m o l t s  However  t h e s l o p e  s i g n i f i c a n t l y d i f f e r e n c e  0.0003 0.0003 0.0004 0.0007 0.0002  n  weights  egg  s i z e  v a r i a t i o n  e x t r a p o l a t e d a t  5.9°C.  of  i n t o  G r a v i d  p o p u l a t i o n  a t  t h i s .  2 7 b ) .  f e m a l e s ,  0.98 0.99 0.99 0.99 0.99  r  SE  t h e 0.31  about  present  weight  and  0.0014 0.0005 0.0008 0.0002 0.0004  Wittmann  from  be  t i m e s .  n o t  ++++++++++-  times t o  1 i n g v u r a ,  account  i n d i c a t i n g  females  1.1-1.4  would  c o u l d  1  10°C, 17-23 days  expected  uq)  development  z e r o ,  0.0109 0.0096 0.0080 0.0085 . 0.0077  p r o p o r t i o n a l  times  20-50  v a r i a t i o n egg  were  0.0170 0.0140 0.0111 0.0117  a t  about  Leptomysis  i n c u b a t i o n (about  days  0.0212  2  +-  than was  i n c r e a s e d w i t h  t h e r e l a t i o n s  were  of  t h e  female's  that  of  t h e male's  p r o b a b l y  p l a t e s  r e l a t e d  i n m a t u r i n g  uropod  d i f f e r e n t  r e g r e s s i o n (p<0.05,  t o t h e  females.  s i z e f o r being  Ancova).  development  0.25 1.0-1.2 mm  Class  0.20 a  •a 0.15  0.10 +  o  2  0.05 +  —I—  —I—  10  15  Temperature  Figure  20  25  (C)  26a. The d e p e n d e n c e o f t h e m o l t f r e g u e n c y on temperature. S i m i l a r l i n e a r r e l a t i o n s h i p s were obtained for a l l size c l a s s e s .  a.  0.4 Uropod Length  Figure  (mm)  26b. The d e p e n d e n c e o f t h e s l o p e s o f t h e m o l t t r e q u e n c y - t e m p e r a t u r e r e l a t i o n s on body s i z e . —  0.12 0.10  <"  0.08 +  c o  E 0.06 a. o 0.04 +  a a a  0.02 +  10 Temperature  Figure  —I—  — —  15  20  —I 25  (C)  26c. The d e p e n d e n c e o f t h e egg d e v e l o p m e n t temperature.  rate  1 02  0.001-1 0.1  1  •—>—  1  1  1 Uropod Length  Figure  2  1  — 3 4  (mm)  27. The d e p e n d e n c e o f t h e w e i g h t s Neomysis m e r c e d i s on a n i m a l s i z e .  40  1  of molts  from  t  30 •  SK  20 •  i  I  9 Q o c  Ul  10 •  F i g u r e 27c. The energy c o n t e n t (± 1 SE) of body t i s s u e , eggs, and m o l t s of Neomysis mercedis . 1=immatures, 2=mature n o n g r a v i d females, 3=gravid female somata, 4=whole g r a v i d females, 5=mature males, 6=eggs, 7=molts  103  Energy  Content  The immature, N.  energy  d e n s i t i e s  (Figure  mature  n o n g r a v i d  female,  mercedis  averaged  22.35  content  of  (±2.14)  J  Oxygen  d i d  (±1.76)  animal  no  s y s t e m a t i c  w i t h  the  number  Wilcoxon  data  a l l  were  as  signed  used  between  the  r e l a t i o n s  v a r i e d  1  . •dry 1  w e i g h t . w h i l e  Eggs  and  an  of  male  Anova)  had  m o l t s  had  a  the  and  energy  averaged  the  r a t e s  8.69  The and  dry  of  oxygen  a  sample  a l l  m u l t i p l e  expected weight  c o m b i n a t i o n s  l o g a r i t h m  of  i n  Consequently  a n a l y s e s .  s a l i n i t y  i n  e n c l o s e d  consumption  use  the  fact  s i m u l t a n e o u s  that  among  l o g - l o g was  (Figure  the  found 28a-e).  measured  However t o  h i g h e r  slope  was  the  t o  s l o p e s  by of  of  uptake  N.  temperature mercedis  the  range  t e s t s  d i f f e r e n c e s .  suggested v a l u e  the  than  generate  an  t r e a t m e n t s  ( S c h e f f e ' s  I n s p e c t i o n  20°C  -  10  the  other  e m p i r i c a l  was  uptake-weight  t e m p e r a t u r e - s a l i n i t y  m u l t i p l e  r e s o l v e 10)  e f f e c t s  consumption  the  (Table  purpose  v a r i a t i o n  t e s t ) .  oxygen  f a i l e d  v a l u e s  my  the  Ancova).  s l o p e s  have  S i n c e  (p>0.05,  t i s s u e s  v a r i a b l e .  of  on  by  may  s i g n i f i c a n t l y  a n i m a l s  rank  and  dependent  c o m p l i c a t e d  slope  female,  of  oxygen  a n a l y s e s  s a l i n i t y  (p<0.05,  i n  temperature  subsequent  the  g r a v i d  J « m g ~  was  I n t e r p r e t a t i o n  on  body  1  r e l a t i o n s h i p  and  the  Uptake  (p>0.05,  r a t e  j«mg~  of  mg" .  consumption  A l l  d i f f e r  (SE=±0.61)  29.26  There  for  not  27c)  ppt  t e s t )  of  the  treatment  t r e a t m e n t s . p r e d i c t o r  of  104  Dry W e i g h t  2 8. m  e  r  c  The e  d  l  s  a  dependence t  5»  6.5,  of  10,  (mg)  oxygen 15,  and  uptake 20°C  on  by  Neomysi  body  weight  106  r o u t i n e occur such  metabolism a t  Woodward  c o n d i t i o n s  Moreover, or  K n i g h t  1975).  20°C  (0.72-0.95)  on  over  slope  -  10  ( c h a p t e r  e f f e c t  e f f e c t s  The  (Table  10.  no  n o n - e x i s t e n t  t r e a t m e n t s  Table  t h e  I s l a n d  has  s a l i n i t y  small  mysids  and  on  1 ) , a  c o n d i t i o n s change  energy  budget  oxygen  uptake  i n  range  v a l u e s  below  o b t a i n e d  s i m i l a r  t o  those  S a l i n i t y ( p p t ) 1 ppt  0. 832 ( 0 .71 - 0 . 9 5 )  0.810  6.5  Temperature  (C)  the  and  d i f f e r e n t  found  f o r  other  i s known t h e  1975).  ppt  0.894 ( 0 . 5 6 - 1 .21 )  0.835 (0 . 7 1 - 0 . 9 6 )  0.915 (0 . 8 1 - 1 . 0 1 )  0. 769 (0 .67 - 0 . 8 7 )  0.881 (0 . 8 1 - 0 . 9 5 )  0.866 (0 . 8 3 - 0 . 9 0 )  1 5  0. 902 (0 .83 - 0 . 97)  0.733 (0 . 6 2 - 0 . 8 4 )  0.784 (0 . 7 0 - 0 . 8 7 )  0.787  0.962 (0 . 8 6 - 1 . 0 7 )  that  oxygen A  10  (0 . 5 9 - 1 . 0 3 )  (0 . 7 4 - 0 . 8 3 )  Knight  (Simmons  10  20  modify  a r e  S l o p e s (and 95% c o n f i d e n c e l i m i t s ) of f u n c t i o n a l r e g r e s s i o n s of log(oxygen uptake) a g a i n s t l o g ( w e i g h t ) under v a r i o u s temperature and s a l i n i t y c o m b i n a t i o n s .  5  to  under  mercedis  ppt  f o r  slope  not  c a l c u l a t i o n s .  N.  10  d i d  1 5 ) .  f r e s h w a t e r  It  i n  t h e  the  were  ppt  w e i g h t , uptake  s i m p l e  t e m p e r a t u r e ,  r a t e  r e g r e s s i o n  of  N.  model  and  s a l i n i t y  mercedis of  the  i n t e r a c t  (Simmons form  and  1 07  log(oxygen  (where  the  weight in  i n  11).  to  sum  to  given  var  uptake  T  i s  The of  the  i n  Table  oxygen  the  accounted  (Table  f i t  rate)  mg,  ppt)  the  uptake  11.  f o r  s a l i n i t y and  d a t a .  The  11.  a  +  i s  b«log(W)  i n  Mg  0  temperature  squares  Table  =  98%  2  i n  made  c o u l d  be  °C, of  a  and the  d e l e t e d  of  f u l l model c o e f f i c i e n t +-  constant weight temperature sal i ni ty  on  •0.334 0.837 0.738 0.008  model  d i d  and The  A  ++++-  the  1  the  somewhat  ,  W  i s  of  the  v a r i a n c e  the  raw  the  dry  s a l i n i t y i n  my  data  r e d u c t i o n  a f f e c t i n g  reduced  r e s i d u a l s  the  model  are  f o r  the  reduced model c o e f f i c i e n t +1  SE  0.041 0.013 0.040 0.007  -0.331 0.837 0.735  oxygen  suggest  been  ( V i d a l  uptake  p e r i o d  +++-  SE  0.041 0.013 0.040  0.98  s i m i l a r  has  copepods  measurement u s i n g  not  s t r u c t u r e .  temperature  1979)  i s  w i t h o u t  0.98  model  - 1  d*log(S)  C o e f f i c i e n t s of the m u l t i p l e r e g r e s s i o n model l o g ( u p t a k e ) = a + b log(W) + c l o g ( T ) + d l o g ( S ) for oxygen consumption by N e o m y s i s m e r c e d i s .  i a b l e  reduced  S  +  n o n - s i g n i f i c a n t  c o e f f i c i e n t s  I n s p e c t i o n  c«log(T)  * a n i m a l " V-h  (n=139)  term  +  s y s t e m a t i c  l o g a r i t h m i c  found  i n  some  d e v i a t i o n s  dependence f i s h e s  of  from  the  metabolism  (Brett  and  Groves  1980c).  r a t e s  were  any  of  a n i m a l s  compared  reduced  r e g r e s s i o n  g r e a t e r  i n  m o l t i n g  which  a g a i n s t  model. a n i m a l s  molted the  Oxygen (p=0.l0,  d u r i n g  r a t e s  p r e d i c t e d  consumption sign  the  t e s t ) ,  was and  108  averaged  1.32  Energy  a l l o c a t i o n  r o u t i n e  S2  v a r i a b l e s .  The  s i z e  over  i n t e r m o l t  of  t h e  non-molting  a n i m a l s .  dependent  which molt  were  uropod  l e n g t h  r e l a t i o n  J « m g -  oxygen  energy  1  0  and  (Jawed  1969)  e v e n t ,  the  i n c r e a s e d that  reached  suggest  4% by  d i o x i d e  that range  1.32  of  m a t u r i t y , using  at  on  the  growth the  the  of  weight  u s i n g  the  1972).  day  the  1975).  d a t e .  p r e c e d i n g r a t e .  body  weight  f a c t o r  Measurements  r a t i o s  m o l t i n g .  sampling  Changes  Neomysis  i n t r o d u c e s  food  M e t a b o l i s m  r e a s o n a b l e  of  growth  the  c o n v e r s i o n  i n  no  f i e l d .  1.  L a n g f o r d  Davidson  the  r e l a t i o n  i n  0:N  d a i l y  a v e r a g i n g  assumed  c h a p t e r  the  growth  the  mature  i s a  by  p r e d i c t e d  a n i m a l s  and  e n v i r o n m e n t a l  i n t e r v a l  a  n e a r e s t over  by  W,  above  c a l c u l a t e d  assuming  v a l u e s  the  a d u l t  over  i n  1968)  and  times  e s t i m a t e d  the  the  determined  was  e v o l u t i o n  t h i s  ( E l l i o t t  observed  r e c a l c u l a t e d  and  Krishnaswamy  p o s s i b l e  than  r e p o r t e d  e q u i v a l e n t s  uptake:carbon  (Raymont  t o  and  m o l t i n g , f o r  u s i n g  was  Growth  use  which  c o n v e r t e d  (Lasenby  2  mysid  r e a r e d  a n i m a l s  l e n g t h  t o  The  c a l c u l a t e d  r a t e s  rates  l a b o r a t o r y those  the  were  t e m p e r a t u r e .  w e l l - f e d  c o n v e r t e d  of  growth,  I s l a n d  g e n e r a t i o n .  i n t e r v a l s  f o r  Woodward  s i z e  t o  was  p h y s i o l o g i c a l  uropod  l e s s  f o r  energy  r e p r o d u c t i o n a t  parent  i n i t i a l  l i m i t a t i o n  was  and  i n i t i a l  the  temperature  14.15  value  a s s i m i l a t e d  between  egg  in  p r e d i c t e d  g e n e r a t i o n s  r e l a t i o n s h i p s  from  of  metabolism  and  from  the  Budgets  The  S1,  times  i n  v a l u e ; an  N.  I f  i n t e r m o l t  the  of  r a y i i  i n  M e t a b o l i s m a t  of  i n t e g e r  u n c e r t a i n t y  S i z e  was  any of was  m a t u r i t y animal  p e r i o d  was  1 09  The  a l l o c a t i o n  of  commence  with  the  l a y i n g .  Yolk  formation  i n t e r m o l t ( C l u t t e r l a y i n g  i n  females  T h e i l a c k e r  produced of  i n c u b a t i o n  i n  t o  not of  males  weights  sperm  produced  undertaken  c o p u l a t i o n s  was  t o  E x c r e t o r y the  oxygen  2.59  J « m g  for  amino  Neomysis 1968).  budget  were  N.  l o s s e s  rate  Cumulative  Approximate  are  and  E x c r e t o r y  m e t a b o l i c  the  not a  p r e c e d i n g  Because  from  the  d u r i n g  the  young  second  because  reared  that  produce  p r o b a b l e  the  m o l t s  assumed  i n d i v i d u a l ;  a s s i m i l a t e d r a t e and  a n i m a l s .  a c i d s  r a y i i  i n d i v i d u a l  of  ( E l l i o t t  2  an  may  i n  c o p u l a t i o n  c o n t i n u e d  breed  e s t i m a t e d  consumption 0  I  o c c u r s  egg  and  1981b).  i g n o r e d  and  before  t o  time.  of  The  the  s m a l l the  i f  s m a l l  numbers number  the  r a t i o  of  were  e s t i m a t e d  of of  g r a v i d  males.  l o s s e s  a m m o n i o t e l i c  free  the  _ 1  t o  was  by  c r u d e l y  mature  s e v e r a l  c l u t c h e s ,  assumed  molt  m o l t i n g  over  energy  was  e l o n q a t a  (Wittmann  t h i s  e f f o r t  females  and  s u r v i v e  c o p u l a t i o n s  one  r e p r o d u c t i o n  r e p r o d u c t i v e of  before  l i n g v u r a  a l t h o u g h  d i d  r a t e  M e t a m y s i d o p s i s  1971),  energy  r e p r o d u c t i o n  growth  s u c c e s s i v e  p e r i o d  female  i n  t o  immmediately  Leptomysis  a l l o c a t i o n  the  r e d u c t i o n  p e r i o d and  energy  of  Ammonia  of  heat  are  c o n f i d e n c e e s t i m a t e d  a  c o n v e r s i o n  1975), and  which  s m a l l  p r i n c i p a l  i n t e g e r  f a c t o r  i s  e x c r e t o r y 1969;  a s s i m i l a t e d  energy  of  a p p r o p r i a t e  amounts  (Jawed  from  (10-15%) p r o d u c t s  Raymont were  et  about  18%  of of a l . of  p r o d u c t i o n .  energy  a n i m a l s  u s i n g  D a v i s o n  the  energy  a l l o c a t i o n s summarized l i m i t s  u s i n g  a  f o r  over i n  the  the  T a b l e s  l i f e t i m e s 12  components  M o n t e - C a r l o  p r o c e d u r e  and  of i n  the  of 13.  energy  which  the  1 10  budget  was  r e p e a t e d l y  parameters  from  of  v a l u e .  the  mean  d i s t r i b u t i o n of  the  (n=l00)  normal  of  The  r e - e s t i m a t e d  d i s t r i b u t i o n s r e s u l t i n g  energy  budgets  12.  L m f c  i o o l  f e t i m e a l l o c a t i o n o l t i n g , m e t a b o l i s m , r female Neomysis m u t c h (mean and 95%  rep o o t  r f v o  o f a t  d s r a  metabo e x c r e t  690.1 (650.2-725.5)  The  g e n e r a l  females  i n  a s s i m i l a t e d  energy  e s p e c i a l l y  i n c r e a s i n g a  e s t i m a t e s  of  the  e r r o r  of  the  p r e c i s i o n  small  true  reduced  the  of  three was  55.6 (28.3%) (52.8-59.4) 7.0 ( 3.6%) (6.7-7.4)  44.7 (25.6%) (41.9-50.3) 5.6 ( 3.2%) (5.1-6.8)  11.3 ( 5.8%) 14.4 ( 7.3%) 25.7 (13.1%) (23.7-28.1) 91.4 (46.5%) (79.1-102.8) 16.7 ( 8.5%) (14.5-18.8)  9.4 ( 5.4%) 11.8 ( 6.7%) 21.2 (12.1%) (19.0-24.3) 87.4 (50.0%) (73.3-110.0) 16.0 ( 9.1%) (13.4-20.1)  energy  r e q u i r e d  f o r  of  W  the  and  maintenance  p r o p o r t i o n  of  the  174.9 (155.0-210.9)  a l l o c a t i o n  g e n e r a t i o n s .  growth  l i f e t i m e  S2  196.4 (178.0-215.8)  p a t t e r n  a l l  temperatures  was  q u a n t i l e s  S1  120.1 (17.4%) (113.4-124.0) 29.0 ( 4.2%) (27.4-29.9) uct i o n p r i n g 27.3 ( 3.9%) i e s 31.4 ( 4.6%) l 58.7 ( 8.5%) (54.6-61.0) lism 407.7 (59.1%) (378.5-436.9) i o n 74.6 (10.8%) (69.3-80.0)  t o t a l  was  standard  a l l  f energy ( j ) t o growth, e x c r e t i o n , and r e p r o d u c t i o n e r c e d i s p r o d u c i n g one d i s t r i b u t i o n l i m i t s ) .  W  m o l t s  95%  ± 1  drawing  b u d g e t s .  Table  growth  w i t h i n  c e n t r a l gave  randomly  Most  r o u t i n e  c o s t s . t o t a l  s i m i l a r  (45-60%)  where  Energy budget.  l o s t  the T h i s  low  m a t u r a t i o n ,  f o r  of  m e t a b o l i s m .  g e n e r a t i o n i n h i b i t  was  w i n t e r g r e a t l y  i n  molts  R e p r o d u c t i o n  1 11  Table  13.  L m N l  i o e i  f l o m  e t m i  t i y t  i n s s  m g i )  e , s .  a l l o c a t i o n of energy (J) t o g r o w t h , m e t a b o l i s m , and e x c r e t i o n f o r male mercedis (mean and 95% d i s t r i b u t i o n  W growth m o l t s metabolism e x c r e t i o n  t o t a l  72.8 (37.0%) (68.9-76.3) 9.3 ( 4.7%) (8.8-10.0)  62.5 (31.8%) (59.9-64.2) 9.4 ( 4.8%) (8.8-9.7)  422.5 (62.6%) (387.2-462.2) 77.3 (11.5%) (70.9-84.6)  96.7 (49.2%) (85.0-109.3) 17.7 ( 9.0%) (15.6-20.0)  105.3 (53.6%) (91.6-115.3) 19.3 ( 9.8%) (16.8-21.1)  f o r  t o  the  a p p r e c i a b l e e f f o r t . energy  f o r  The  55%)  i n  s e x u a l  m a t u r i t y  female  of  producing  (about  that  amount  not  budget,  p r o p o r t i o n  a f t e r  accounted  the  the  s t a r t  t o t a l the  but  of  r e d u c t i o n  so  but  i s , the  energy  i n c u b a t i o n  p e r i o d ,  was  the  t o t a l  f r a c t i o n  became  a l l o c a t e d  that  of  l a r g e  energy  a  an  r e p r o d u c t i v e  of  the  a v a i l a b l e  p r o g r e s s i v e l y  s m a l l e r  b r e e d i n g . energy  g e n e r a t i o n i n  the  r e p r e s e n t e d and  196.4 (178.7-209.1)  young,  l a s t  a s s i m i l a t e d same  c o n t i n u e d  energy  f o r a  animals  r e p r o d u c t i o n  r e p r o d u c t i o n  energy  the  l i f e t i m e  t o  the  d u r i n g  i m p l i e d  growth  196.5 (179.3-214.2)  o v a r i e s  immature  females  of  and  Growth  component  and  8-13%  r e p r o d u c t i o n  shunted  S2  140.6 (20.8%) (126.5-148.9) 34.5 ( 5.1%) (32.3-36.2)  675.0 (617.2-727.2)  accounted to  S1  12  and  f o r  males  13).  T h i s  r a t e  of  females  r e - c h a n n e l i n g  of  energy  that  the  d u r i n g  the  a l l o c a t e d  s i m i l a r  (Tables  growth  a  was  a l l o c a t i o n i n c u b a t i o n  c l o s e l y  of p e r i o d  b a l a n c e d  the  3-4  as  a t from  energy  t o  since  t h e  male  and  budgets.  Females  i n  the  W  g e n e r a t i o n  used  times  much  energy  112  over  t h e i r  l i f e t i m e  l a r g e r  s i z e  females  r e s u l t e d  producing to  about  had  an  was  about  The  each 20-22  energy  m a t u r i t y i n more  J  d e c l i n i n g  W  young  o f  f o r t h e S  S1  was  g e n e r a t i o n .  The  (11.4-13.1%)  when  r e p r o d u c t i v e 29%  o f  3.9%  e f f o r t s  p r o d u c t i o n ) . o f  t h e  g e n e r a t i o n , Some  t o t a l  and  females  s e v e r a l  c l u t c h e s .  c l u t c h e s  a r e given  temperatures amount  o f  energy  c o s t  t o t a l  i n  were  t h e  a  energy of  W  Energy i n  p e r young  by  expended was  egg  e f f i c i e n c y  (30%)  h i g h e s t i n  a l s o  of  budget  t h e  had  a l l o c a t e d  8.0-9.0%)  made  i n  a  i n  t h e  S1  content t h e W  of  l a r g e r  (Table  1 2 ) .  p r o d u c t i o n , (about  o f f s p r i n g  g e n e r a t i o n ,  W  g e n e r a t i o n  g e n e r a t i o n of  t o  t h e  s i g n i f i c a n t l y  i n a l l g e n e r a t i o n s  5.8%  t h e 28-  comprised f o r t h e SI  g e n e r a t i o n .  and  S1  budgets  Table  experienced  each  g e n e r a t i o n .  g e n e r a t i o n  energy  S2  s i m i l a r  t h e  t h e budget  S2  of  compared  Since  lowest  p r o p o r t i o n  f o r t h e S2  i n  w i n t e r  cost  a s  f o r t h e W  and  g e n e r a t i o n s  budget  5.4%  3%  ( 9 5 % l i m i t s  as  The  t h e  J , t h e energy  13.1% (12.2-13.9%)  expressed  (25 J  t h e  ( 4 1 % ) .  summer  and  However,  and  of  t h e l i f e t i m e  f e m a l e s ) .  s t a t i o n a r y  8.5%  e f f o r t s :  s i z e  higher  0.76-1.2  t h e  r e p r o d u c t i v e 12.1%  summer  g e n e r a t i o n  o f  about  The  somewhat  Although  ( p r o d u c t i o n / a s s i m i l a t i o n ) was  e f f i c i e n c y  p r o p o r t i o n  egg  female,  g e n e r a t i o n s  g e n e r a t i o n .  r e p r o d u c t i o n  p e r  about  females.  s m a l l e r  from  e f f i c i e n c y  n e t energy The  and  f o r young  i n t h e growing  g e n e r a t i o n  remained  content  6%  summer  young  n e t energy  (45%)  high  a t  as  14.  g r e a t l y  f o r The  these on  g e n e r a t i o n s  may  females regime  animals  producing of  a l t e r e d  metabolism  b u t  reduced,  13  t o  two  i n c r e a s i n g t h e  t h e J  produce  r e l a t i v e l i f e t i m e  p e r young  f o r  1 13  both  the  Table  W  and  14.  L m i c  S1  females.  i f e t i m e a l l o c a t i o n of en o l t i n g , m e t a b o l i s m , e x c r n female Neomysis m e r c e d l u t c h e s (mean and 95% d i  erg e t i i s s t r  y (J) o n , an which i b u t i o  W growth molts  t o growth, d r e p r o d u c t i o n produce two n l i m i t s ) .  S1  140.3 (16.4%) (129.3-146.4) 34.0 ( 4.0%) (31.8-35.4)  69.9 (24.8%) (65.7-75.2) 9.3 ( 3.3%) (8.7-10.2)  58.4 ( 6.8%) 36.9 ( 4.4%) 95.3 (11.2%) (87.7-99.2) 493.7 (57.8%) (451.1-535.2) 90.4 (10.6%) (82.6-97.9)  25.8 ( 9.2%) 18.2 ( 6.4%) 44.0 (15.6%) (40.7-47.9) 134.1 (47.6%) (116.8-151.3) 24.5 ( 8.7%) (21.4-27.7)  r e p r o d u c t i o n o f f s p r i n g o v a r i e s t o t a l metabolism e x c r e t i o n  t o t a l  853.7  281  (795.3-909.3)  .8  (255.0-309.5)  D i s c u s s i o n  P h y s i o l o g i c a l  The s e v e r a l in  Rates  growth phases  uropod  t e m p e r a t u r e .  i n  s i z e  w i t h i n  l e n g t h A  was  l i n e a r  each  of of  N.  m e r c e d i s  which  c o n s t a n t dependence  i n  the time  of  c o u l d average but  growth  be  r e p r e s e n t e d  d a i l y  v a r i e d r a t e s  increment  d i r e c t l y on  by  w i t h  t e m p e r a t u r e  114  was  a l s o  noted  s p e l u n c o l a  and  e u p h a u s i i d weak  Gaudy  Leptomysis  Euphausia  Because  as  of  uropod  d i d  s p e c i f i c per  [9]  Pezzack  growth  =  has  dW/Wdt  =  growth  over  the  from  range as  i s  1980a).  i s  p o i k i l o t h e r m s  f o l l o w s Lasenby  ( V i d a l  the  1982)  the  N.  a  Neomysis amer  body  l e n g t h %  found  i n N.  the  i c a n a .  weight  i m p l i e s  change  and that  i n  body  +  0 . 0 0 4 0 4 7 - T ) • ( W  w i t h  but  '  i n c r e a s i n g  d e c l i n e s  3 6 6  1972;  dependence  of  )  temperature  w i t h  (Shushkina  (-0.33  0  i n c r e a s i n g B r e t t  the  s p e c i f i c  i s common  i n  t o  r e p o r t e d  r e l a t i o n s h i p  -0.41) i s  f i s h  not  1979;  and  the  ( B r e t t  g e n e r a l  i n  1980a).  the  s p e c i f i c  f o r  (1984)  between  the  Hemimysis  (1966)  f o r  uropod  as  case  range  m e t a b o l i c  between  the  mercedis  of  d i f f e r e n c e a  et_ a _ l .  (1979)  weight  dependence  that  t o  the  of  assumption  leads  20°C  form  and  L a s k e r  temperature  i n c r e a s e s  t o  t h i s  q u a l i t a t i v e from  rate  f o r i n  of  f o r  form  a l l o m e t r i c  However  The  on  (-0.01526  5  found  exponent  1979).  by  Toda  e x p r e s s e d  commonly The  rate  weight  (1979)  and  Corey  growth  the  s p e c i f i c  growth  and  r a t e ,  The  V i d a l  1 i n g v u r a  dependence  c o n s t a n t  day,  G  weight,  G u e r i n  the. e x p o n e n t i a l r e l a t i o n s h i p  l e n g t h ,  weight  and  pac if i c a . w h i l e  e x p o n e n t i a l  intermedia  the  by  growth  rate  i n g e s t i o n rate  s p e c i f i c  the  r a t e s  growth the  the  of  growth  consumption on  s i z e i s  and  form  f u n c t i o n  (Johnston  and  t e m p e r a t u r e .  The  p r o p o r t i o n a l  rate the  and  rate  the  to  m e t a b o l i c  the rate  115  [10]  G  where  H  While f a c t  =• { 0 . 0 0 3 1 3 2 - H . T  i s t h e number t h i s  p r e d i c t s  t h e  " l i n e a r i t y " r a t e s  of  l e s s  than  r a t e s  In  range  t h e  observed agree  dependence  decreases and  i n  from  t h e  p r e d i c t s i n c r e a s e d o r  m a t u r i t y  s i z e  decreases  ( H a r t n o l l  1982).  The  have  a  Based  and  t h e  m a t u r i t y r i s i n g f i x e d on  my  would  improve  t h e  t h e  observed a r e  f o r  l a r g e  ( e q u a t i o n  of  10)  temperature  r e l a t i o n s h i p A d u l t  body  r a t e s between  s i z e  mercedis  a l s o  (chapter  1979; M a t s u i d a r a e x p r e s s i o n r a t e s f o r  number  m o l t s  of  i f t h e  of d a t a ,  d e r i v e d  mercedis  a t  N.  t o m a t u r i t y i s E q u a t i o n of  Many  m o l t s t h e  a l .  10)  number  t e m p e r a t u r e s .  e_t  1)  ( e q u a t i o n  temperature.  number  o b t a i n e d ;  development  rate  o n l y  i n  temperature  m a t u r i t y  r e a r i n g  were  e f f e c t s  m e t a b o l i c  i n c r e a s i n g  f e e d s .  1.5-3.  and  Guerin  2 0  dependence  e s p e c i a l l y  i n N.  growth  i f  w i t h  of  1980b).  and  l i n e a r  p r e d i c t e d  f a c t o r  temperature  a t  a t  and  '  temperature,  w i t h  10,  growth  s i z e  w i t h  rate  inverse  consumption  temperatures  copepods,  of  a  0  }-W"  mysid  t h e d a t a  t h e d i f f e r e n t  (Gaudy  decreased  reduced  a  9)  7 3 5  on  r a t e s  e q u a t i o n  ( V i d a l  1984).  d e c r e a s e s  p r e d i c t s  a s  mysids  observed a  s i z e  i n c r e a s i n g  et. a _ l .  by  '  However,  growth  observed  body  other  Toda  such  and  w i t h  1952;  f i x e d  t h e  from  which  0  t h e  dependence  r e l a t i o n .  w i t h i n  t h e b o d y - s i z e  temperature  that  i n growth  ( e q u a t i o n  copepods,  f o r  day  a t  s p e c i f i c  s e v e r a l  account  0.007097-T  i n d i s t i n g u i s h a b l e  p r e d i c t e d  o n l y  -  p e r  v a r i a b i l i t y  of  those The  hours  t h e observed  change  a n i m a l s . growth  of  5 1 5  '  c u r v i l i n e a r  temperature  b e t w e e n - i n d i v i d u a l  on  a  i t i s v i r t u a l l y  over  of  0  molts  9 t o  C r u s t a c e a ,  t o  number  m a t u r i t y of  p o s t -  116  embryonic N.  molts  m e r c e d i s .  number  of  s t u d i e d . matured  t o  Gaudy  t o  B e r r i l l  and  a f t e r  molts  t o m a t u r i t y  other  found  mysids  c o n s i d e r a t i o n s  to  vary  found  copepods  food  copepods  c o n c e n t r a t i o n  were  r e l a t i v e l y  r e s u l t s  o b t a i n body  s i z e  summer  would  p e r m i t  d e n s i t y w i t h  then  food  as  food i n a  food  c o n c e n t r a t i o n  body  s i z e  more  dependent  The  such  s m a l l e r  temperature t o  f i e l d  t h e e f f e c t  of  as  of  of  might  w i t h  i n  r e s o u r c e  a t  s i m i l a r  l e v e l s  body  s i z e  1980a). o f  more  V i d a l s e v e r a l  a t  growth  h i g h  r a t e s  temperature l a r g e r  as  copepods I f  s i m i l a r  d u r i n g  r a t e s t h e  a d u l t  i n t h e under  p o p u l a t i o n body  l a b o r a t o r y  s i z e r e a r e d  temperatures  w h i l e  of than  r e d u c t i o n  growth  occur  t o  m e r c e d i s .  p o p u l a t i o n  i n w e l l - f e d  a n i m a l s  apply  q u a l i t a t i v e  l e v e l s .  h i g h  r e d u c t i o n  noted  by  these  e n e r g e t i c  i n N.  p r o g r e s s i v e  i n t h e n a t u r a l  t h e maintenance  of  Thus  maximum  food  t h e  t h e number  f o r growth  rates on  e t  l i k e l y  ( V i d a l  i n f l u e n c e d  t h e growth  mercedis  very  p r o p o r t i o n a l l y  s t r o n g l y  r e l i c t a Toda  observed  fashion  they  i n t e r m e d i a ;  i n t e r a c t  Consequently  which  However,  a t m a t u r i t y  complex  l o w .  N.  t h e  c o n c e n t r a t i o n  r e s o u r c e s ,  compared  r e p r e s e n t  t h e s i z e  observed  i n c r e a s e d .  i n c r e a s e d  a n i m a l s  of  more  a d u l t  d e c l i n i n g  Neomysis.  p r e d i c t  and  f i x e d  Mysis  between  i n Neomysis  genus  w h i l e  f o r  r e l a t i o n  14-15 i n a  s p e c i e s that  t h e  a t  were  suggest  about  suggest  t h e two  data  w i t h  than  a l s o  comprehensive  r a t e s  i n c r e a s e d  t o be  temperatures.  i n v e r s e  t h e c r i t i c a l  temperatures small  and  two  temperature  dependence  growth  that  a t  c o r r e c t l y  Temperature  f o r  Lasenby... ( 19 8 3 )  and  i n  (1979)  m a t u r i t y  an  f a r t h e most  temperature  G u e r i n  12-13 molts  (1984)  by  r e p r o d u c t i o n seems  and  molts  a l .  are.  f i r s t  t h e  may  g e n e r a l  .117.  correspondence r e l a t i v e r a t e s my  of  s m a l l  s i n c e  g e n e r a l l y  (Table  changes  i n  q u a l i t a t i v e l y  l i n e a r  The weights weight about the  the  s l o p e s were  3.5%  a  weight  was  weights  r a t e s  of  cannot  e f f e c t s  of  of  from  the  the  be  growth  t e s t e d  with  r e s o u r c e  immature  dependent  rate  of  f r e q u e n c y ,  s i z e  N.  l e v e l s  mysids  are  those  of  than  w i t h  those  of  of  than  l o g a r i t h m i c  by  the  the  other  dependence  mysids  was  of  the  body  same  i n  s i z e  dependence  male  p r o p o r t i o n  N.  (9.2%)  pouch  a l t e r e d  the  body  i n c r e a s i n g  f r a c t i o n  of  the  N.  mercedis  e l o n q a t a l e s s  c o n t e n t .  than  In  of  brood  c o n s i d e r a b l y  7 ) .  frequency  were  (Mauchline  1980,  b e t t e r  are  ( C l u t t e r those  of  d e s c r i b e d  by  advocated  a by  the  molt  and  body  so  that  the  molt  m e r c e d i s ,  energy  Metamysidopsis  r i s i n g  (equation  r e l a t i o n  the  i n  w i t h  s i z e  molt  p a r t l y  1980).  c o n s t a n t  an  r e s u l t e d  i n c r e a s e d  i n c r e a s i n g  dependences  to  mercedis  which  temperature  the  of  l a r g e  the  temperature  growth  s i m i l a r  (1977,  was  f o l l o w  c o n c e n t r a t i o n  growth  decreased and  r e l a t i o n  Mauchline  the  and  but  would  s p e c u l a t i o n  examine the  molt  temperature  p. 2 1 0 ) ,  not  food, T h i s  s t r o n g l y  i n  temperature The  d i d  r a t e s  7 ) .  Changes from  from  However  more  growth  a n i m a l s .  I  growth.  a d u l t s  the  independence  data  on  of  the  females  s i m i l a r  body the  form  so  body to  and  T h e i l a c k e r  of  c l a d o c e r a  w e i g h t ,  or  development  of  that  the  w e i g h t . those 1971),  (10-30%,  molt Molt  (13%) but  of are  B o t t r e l l  1975). S i m i l a r l y embryonic  t o  the  development  i n t e r m o l t was  p e r i o d ,  s t r o n g l y  the  temperature  d u r a t i o n dependent  of i n  118  N.  mercedis  b u t . was  nongravid  females  d u r a t i o n  i n  induced t h e i r  r e l a t i o n s  are  embryonic  that  may  a l t e r rates  m u l t i p l i c i t y  e n v i r o n m e n t a l l e v e l the  of body  s i z e  metabolism  oxygen  1975)  t h e i r  but body  s i z e  metabolism d e s c r i b e d  by  e f f e c t s  model  of  rate  assumes i s  (Comita  indeed 1968;  that  = the  independent V i d a l  N.  some 1981b)  mercedis  1971,  mercedis  My  l i t t l e  fed  a f f e c t e d l e v e l  of  the  animals  by of  s l i g h t l y  and  compared  measurements  g e n e r a l  season  (Simmons  n e g l i g i b l e  a c t i v e ,  p r e v i o u s  In  the  and  by  n u t r i t i o n ,  p.874).  a l t e r  m a t u r i t y ,  and  s t a g e ,  i n s t e a d  n o r m a l l y  a  i n  i n f l u e n c e d  p r e s e n t  i s  l a r g e l y  the  d u r a t i o n  Wittman  are  metabolism  N.  temperature.  log(M) which  are  a c c l i m a t e d , a  i n  The  i n  egg  c u r v i l i n e a r  s i z e  1975b;  o n t o g e n t i c  Sex,  consumption  and  of  1980c).  egg  of  t i m e s .  (Kinne  which  c a r r y  dependence  observed  i n c l u d i n g  of  that  1984).  i n v e r t e b r a t e s  behavior  v a r i a b l e s  S t e e l e  hormonally  a l t h o u g h  w i t h  s i z e  s i z e ,  dependence  i n f l u e n c e  and egg  f a c t o r s  and  ( V i d a l  Meyers  a q u a t i c  c o n d i t i o n s ,  e n v i r o n m e n t a l  of  of  a c t i v i t y ,  1975;  g e n e r a t i o n of  l i n e a r  f o r  i n t e r m o l t  from  Crustacea  common,  c o r r e l a t e d  i n  r e s u l t s  other  i n t e r v a l  i n c r e a s e d  i s  ( S t e e l e  v a r i a t i o n s  M e t a b o l i c a  i s  i n  i n t e r m o l t  The  observed  ( B o t t r e l l  c r u s t a c e a n s  1)  The  temperature  known  the  (chapter  on  the  p r o b a b l y  known  1976).  development  p e r a c a r i d a n so  i s  than  s i z e .  females  which  r a t e s  g r e a t e r  s i m i l a r  brooding  (Lawlor  development  of  of  a n e c d y s i s  eggs  much  Knight to  those  " r o u t i n e " are  w e l l  form +  b'log(W)  body of  1980c).  s i z e  +  c - l o g ( T )  dependence  temperature, The  above  as  of i s  a l l o m e t r i c  the  m e t a b o l i c  o f t e n model  found gave  a  1 1 9  weight  exponent  value  of  S i m i l a r  0.81  15.  0.837±0.013  f o r  Neomysis  Exponents f o r the r a t e s i n m y s i d s .  l e v e l  i n c r e a s i n g  (1975)  s a l i n i t y  N.  i n t e g e r .  10  ppt)  and  seawater which  a l s o  (about  may the  Indeed,  no  f e c u n d i t y  and  10  changes changes  are  Corey  from i n i n  1973;  at  of  i n t e r n a l  as  i n  the  i n  m e t a b o l i c  of i o n  uptake uptake A r t e m i a  1976).  e f f e c t .  N.  a t  the  of may  or  noted and  used  s t u d i e s .  Simmons below  of  i f growth 1976).  i n  t o  l o a d s . r a t e s  or  E s t u a r i n e  normal  O s m o r e g u l a t i o n  30%  e f f e c t s  osmotic  below  i n (0-  i t i s d i f f i c u l t  v a r y i n g  (Lockwood  above  I  v a r i e t y  occur  Simmons  mercedis  s a l i n i t i e s  changes,  with  (1977)  which  p r e c e d i n g  e f f e c t  s a l i n i t i e s  Lockwood  15).  i n c r e a s e d  l i t t l e  s a l i n i t i e s  Because  oxygen  of  E l g e r s h u i z e n  uptake  than  oxygen  (Table  mercedis  had  and  s a l i n i t y  p p t ) .  reduced,  osmoregulate  no  mysids  1975).  study  N.  s a l i n i t y  range  s m a l l e r  found  r e s u l t  p r e d i c t  mysids  much  i n  oxygen  the  K l e k o w s k i  dependence  t h i s  V l a s b l o m  a l t e r e d  However  was  K n i g h t  and  but  Winberg's  Simons and K n i g h t 1975 Jawed 1973 S h u s h k i n a e t a l . 1971 V l a s b l o m & E l g e r s h u i z e n 1977 Lasenby and L a n g f o r d 1972 F o u l d s and Roff 1976 G a u d y e_t a _ l . 1 9 8 0 G a u d y e t a l . 1980  metabolism  temperature  K n i g h t  that  of  t o  r e f e r e n c e  0.774 0.62 0.81 0.58-0.83 0.75 0.778 0.55-0.72 0.38-0.70  Leptomysis l i n g v u r a Hemimysis s p e l u n c o l a  c l o s e  and  other  weight  0.837  N. m i r a b i l i s N. i n t e g e r Mysis r e l i c t a  and  f o r  b  mercedi s  The  (Duncan  obtain  s p e c i e s  i s very  which  Crustacea  exponents  weight  Table  of  N.  (Dormaar i n t e g e r  120  and of  N.  r a y i i  f r e e  Jawed  i s  amino  1969),  thought  a c i d s but  r a t e  A  and  d o u b l i n g  by  a  i n c r e a s e d  i n  M y s i s  animals  and  those  v e r t i c a l  m i g r a t i o n of  independence swimming  speeds  t h o r a c i c as  w e l l  Roff  appendages as  f o r  to  i s  ejt  1968;  s l i g h t .  e f f e c t s  i n c r e a s e d d o u b l i n g  a_l.  on  metabolic  the  of  metabolic  the  temperature  t i m e s . mysids  may  and  Roff  not  d i f f e r  and  at  only  weakly  (1976)  showed  between  speeds  i n c r e a s e d  l e n g t h s r a t e s  from  by  from  the  a  and  Manton  oxygen  observed of  The  continuous  1.2  r e l a t i v e at  normal  use  f e e d i n g 1928;  on  a c t i v e  f a c t o r  l e v e l s  r e s p i r a t o r y and  (Cannon  t h a t  to  second.  a c t i v i t y  depend  r o u t i n e l y  s i m i l a r  only  per  r e s u l t s  generate  locomotion  cost  p r o d u c t i o n  of  the  c u r r e n t s  Foulds  and  1976). My  data  i n c o r p o r a t e s made the  probably  a  or  (Raymont  s i m i l a r  w h i l e  body  metabolic  had  weight  swimming  2-4  of  body  d i d  r a t e s ,  e x c r e t i o n  m e t a b o l i c  s i z e  Foulds  r e l i c t a  the  c a t a b o l i s m  the  1.79  r a t e s  uptake  speeds  of  1.66  l e v e l s .  at  the  by  a c t i v i t y i n  of  r a t e  M e t a b o l i c  p r o t e i n  body  f a c t o r  the  i n v o l v e  e v i d e n t l y  Temperature r a t e s .  by  to  on  r e c e n t l y  copepods  r e l a t i o n  l i t t l e  r a t e s  ( V i d a l  independent  of  food  assume  w i t h  the  r o u t i n e  metabolism  fed of  a n i m a l s .  s i n c e The  have  found  c o n c e n t r a t i o n s metabolic  that  metabolism  p o i k i l o t h e r m s  1980c)  between I  the  d i g e s t i v e  metabolic  1979).  on  the  q u a n t i t y  r a t e  m e t a b o l i c of  r a t i o n .  the  the  whereas and  of  of  f i s h  r a t i o n s  r a t e  of  mercedis  r a t i o n  ambiguous.  l e v e l  N.  measurements  e f f e c t s are  of  N.  l e v e l  S t u d i e s  metabolism show ( B r e t t  were  to  on on be  a  d i r e c t  and  Groves  mercedis  changes  121  In study)  s e v e r a l  c o n s i d e r a b l e  (1966, to  p.1298)  molt,  but  conclude  t h a t  the  expense  m e t a b o l i c higher  T h e i l a c k e r  the  on  day  are  organic  the of  low  of  body  organism,  very  s i m i l a r  as  of  to  obtained  values  for  Crustacea,  they  1977). e_t  a l .  1978)  and  1965;  are  omnivores  as  e s t u a r i e s , a  group, The  The  of  l i e l i p i d  no  many  the  they  are  p r e c e d i n g  data  resource  suggest  and  the  such  as  C l u t t e r  and  l a r g e l y i n  c o n s i d e r a b l e depressed  N.  mysids the  on  (Table  i s  1971;  Because  f o o d - r i c h may  v a l u e  small  seasonal  16).  r e p o r t e d  modal  T h e i l a c k e r  mysids  mercedis  range  the  mysids  1978).  of  a  whole  above i n  p e r i o d .  1966).  and  w i t h i n  h  i n c r e a s e  i s  other  r e l a t i v e l y  d e n s i t i e s  r a r e l y  impose  times  l i v e s  moderate  s i g n i f i c a n t  Hopkins  i n h a b i t  energy  f o r  f r a c t i o n  shows  i n t e g e r  eggs,  somewhat  C l u t t e r  and  N.  (Lasker  are  1966;  Johnson  and  m o l t s ,  mysids  1966;  a_l.  f e e d i n g  e u p h a u s i i d s  24  e_t  may  i f  the  at The  1.32  products  the  m o l t i n g  d e n s i t i e s  v a l u e s  Raymont  so,  over  to  a n i m a l " .  storage  t h a t  e s p e c i a l l y i n  of  the  him  c o n t i n u e s  averaged  animals  suggests I f  of  mercedis  Raymont  w i t h  energy  as  1965;  i n g e s t i o n .  energy  N.  c o n c e n t r a t i o n s  L i n f o r d  molt  r e s e r v e s  non-molting  ( L i n f o r d  The  ( L i n f o r d  m e t a b o l i c  m o l t i n g  those  the  Hopkins  c o n t i n u e d  of  a  t h i s Lasker  e u p h a u s i i d s  and  the  and  m o l t i n g .  n e c e s s i t y  While  15%,  at  i s  the  ( G r i f f i t h s  1979;  " m o l t i n g  a s s o c i a t e d  of  non-growing  Guerin  l e a d i n g  d a i l y  s t r e s s  that  o c c u r r e d  and  s h o r t e r ,  1971);  metabolism  has  (Gaudy  p r o g r e s s i v e l y  carbohydrates  i t s  observed  r a t e s  have  s t u d i e s  m o r t a l i t y  became  than  Mysids  on  r e a r i n g  (10-  Johnson v a r i a t i o n  most  mysids  areas  such  i n d i c a t e  t h a t ,  l i m i t e d . importance  of  the  animal  1 22  Table  16.  Energy  d e n s i t i e s  species  ( J mg"  body  s i z e  and  a .: S h u s h k i n a e t b : C l u t t e r and T c : Lasenby and L d : Hakala 1979 e : Tyler 1973 f : Johnson and H  t h e  c o n t r o l l i n g  temperature  t h e  opkins  of  components  of  temperature  dependences  of  rates  reduction  i n  t h e  lead  t o  r i s e s . of  a The  t h e  change  v a r i a t i o n  i n  temperature r a t e  a t  dependence  s e l e c t i o n temperature  e f f o r t  schedule.  t h e  large  (chapter t i e d  of  8.69 10.38 -  of  study a b c d e f  p h y s i o l o g i c a l  molting a t  growth  of  body  be  and  animals  and  growth  as  temperature  rate  a  consequence  i s and  metabolism  The  development  and  over  thus of  i n s i z e  t o  s i z e  and  l i m i t s  t h e  successive  i n f l u e n c e s  a d u l t s .  i s p o s i t i v e l y  1 ) , t h e v a r i a t i o n  i n t h e s i z e  maturity  accumulated  s u r v i v o r s h i p  i n  among  somatic  s i z e . egg  r a t e s  energy  and  i n g e s t i o n  growth  t o v a r i a t i o n  t h i s  D i f f e r e n c e s  s i z e  and  can  mysids.  1978  f o r reproduction  and  against  i n t i m a t e l y  of  energy  i n t e r v a l s  reproductive  is  temperature  which  i n t e r b r o o d  budget.  responses  o f  reference  a s s i m i l a t e d  i n t h e somatic  d i f f e r e n t  molt  29.26 29.96 -  dependence  energy  animal)  a l . 1971 h e i l a c k e r 1971 a n g f o r d 1972  a l l o c a t i o n t h e  whole  eggs  Neomysis mercedis 22.35 N. m i r a b i l i s 22.89 Metamysidopsis elonqata 19.25 Mysis r e l i c t a 22.59 20.91-28.03 M. s t e n o l e p i s 19.72 Taphromysis bowmani 18.52-19.72  references  1  both  Because  c o r r e l a t e d  with  with  temperature  i n t h e a g e - s p e c i f i c  s u r v i v o r s h i p  123  L i f e  H i s t o r y  The  a b r u p t  m a t u r i t y  has  T h e i l a c k e r 1981; of  Theory  Toda  energy  d e c l i n e  been  m a t e r i a l .  Gaudy  a l .  from  females  r e l a t i v e  t o  energy  c o n t e n t  of  l a y i n g of  at  the  10°C,  and  c l u t c h  a t  d i f f e r e n t and to  growth  males  (the  i s  terms  d e c r e a s e d  of  Current r e p r o d u c t i v e presence  l a r g e l y f i s h  ( F e i f a r e k the  low  of  the  of  a  i n  of  et  1983),  subsequent  broods  r e p r o d u c t i o n  may  not  females s u g g e s t s  a f f e c t  cost  t o  i n  the  p r e c e d i n g  energy  d e s p i t e  of  females of  growth  energy  rate  r e p r o d u c t i o n . the  c u r r e n t  egg  c o n t e n t  agreement,  s i z e ,  of Since  r e d u c t i o n r e p r o d u c t i o n  impose  a  second  s u r v i v o r s h i p .  A l t h o u g h  marsupium  r e n d e r s  v i s i b l e ,  i n c r e a s e d  p r e d a t i o n  r e p o r t e d  observed  s u r v i v i n g that  l o n g e v i t y .  i n  d i r e c t  the  as  i n  p o t e n t i a l .  reduced  brood  such  of  body  a l s o  f e m a l e s ,  of  the  reduced  "cost"  on  g r a v i d  i n c i d e n c e  the  mature  accumulate  a l l o c a t i o n  q u i t e  was  of  d i r e c t  animal  a_l.  r a t e s  l i t t l e  may  d e v e l o p i n g  r e p r o d u c t i v e  i n t e r m o l t  c l o s e  r e p r o d u c t i v e  terms  of  budgets  r e a l  r e p r o d u c t i o n c o s t  The  et a l .  r e - a l l o c a t i o n  t o  of  and  a  energy  dependent  f u t u r e  the  s e x u a l  ( C l u t t e r  t o t a l  t h a t  a  growth  75-80%  e n e r g e t i c  imposes  r e p r e s e n t s formation  over  a t  Cuzin-Roudy  s u f f i c i e n t  20°C.  making  the  t r a n s p a r e n t  on  and  suggests  growth  i s  females  mysids  1979;  somatic  c l u t c h  15  s t r o n g l y  the  accumulate  l a t t e r  somatic  the  t o  r e p r e s e n t s  f e c u n d i t y  t o  i n  of  s e v e r a l  p r o b a b l y  immatures the  rate  G u e r i n  growth  r a t e s ,  r e p r o d u c t i o n )  females  and  decrease  growth  i n  and  1984)  somatic  The  the  observed  1971; et  i n  f o r  (chapter t o  the  the by  some  copepods  1 ) .  However,  produce e n e r g e t i c  second  or  c o s t s  of  124  Energy  a l l o c a t e d  accumulated  over  growth  r a t e s  a t  energy  from  p o t e n t i a l be  the  mature  p r e c e d i n g  s e x u a l  m a t u r i t y  somatic  rate  of  f e m a l e s . w i l l  i n t e r m o l t , p e r i o d .  growth  a c c u m u l a t i o n between  The  be  amount  t h i s  w h i c h ,  Thus,  s u c c e s s i v e  the  d i f f e r e n c e  c l u t c h e s  t o  the  a  i n  c o n c e r t  w i t h  development,  w i l l  c o n t r o l  the  the  i s , the as  i n v e r s e l y  w i t h  the  same  female,  i s  the  p r o d u c t s  r a t e s  the  the  growth  i n of  then  of  the  the  f o r  of  the  development  on  s i z e  dependence  energy  and  s u c c e s s i v e  egg  r a t e s  w i l l  immature  d u r a t i o n  temperature of  r e d u c t i o n  r e p r o d u c t i o n  times  l e s s  s i z e .  and  of  egg  a v a i l a b l e  f o r  i n v e r s e l y  w i t h  p e r i o d  i s  of  s u c c e s s i v e  c o n t i n u e d broods  of  growth  w i l l  impose  or  energy  body As  an  w i l l  a l s o  i s  weight  s i n c e  the  v a r y  observed both  a c q u i s i t i o n of  t o show of  r e p r o d u c t i o n ,  temperature  i n c r e a s i n g l y  p e r i o d . i n t e r m o l t ,  weight  r e q u i r e m e n t s of  accumulate  brood  over  w e i g h t ,  c l u t c h  1 ) .  the  females  s u c c e s s i v e  of  the  (chapter  behind  development  body  the  v a r i e s  l a r g e r  each  of  But  f r a c t i o n  lags  egg  a c c u m u l a t i o n  dependence  because  over  p r o p o r t i o n  body  energy  the  rate  s i z e ,  energy  c o n s t a n t s i z e  growth  maternal  a  s u r p l u s  the  f o r  be  d i v e r s i o n  accumulated  amount  w h i l e  p o t e n t i a l  expressed  a  9)  of  p r o p o r t i o n a t e l y  remain  s p e c i f i c  (equation  independent  That  energy  energy  the  t o  c l u t c h e s .  Because weight  of  of  temperature,  s u c c e s s i v e  r e p r o d u c t i v e  growth  l a r g e l y  the  t o  b r o o d i n g  dependence  I f  r e p r e s e n t s  d i f f e r e n c e  f o r  seems  i n t e r m o l t .  the of  broods  severe  regimes, s t r e s s e s  on  a n i m a l . The  o p t i m a l i t y  arguments  which  u n d e r l i e  much  of  l i f e  125  h i s t o r y  theory  " c o s t s "  i n terms  or  s u r v i v a l  of  of  e_t  underpinnings The  such  summer  t h e o r y .  g e n e r a t i o n s  m o r t a l i t y the  h i s t o r y  theory:  r a t e s  m o r t a l i t y i n  maintenance  c o s t s  N.  temperature i n t e g e r West  i n  breed  at  The  R i v e r  1982).  The  c o n s t r a i n t  arguments  n o t  which  t o w i n t e r  breeding  e f f o r t t o  measuring  1.5  t h e  seen  where The  i n c r e a s e d w i n t e r  r e s u l t e d  i n t h e  generation under  of  that  Bremer  there  i n Neomysis N.  of low  Neomysis  1971; Parker 1955;  i n  times  a t  not u n i v e r s a l  a r e  a d u l t  r a t e s .  p o p u l a t i o n s  t o and  generation  from  (Kinne  t h e  d i r e c t i o n  about  (Mauchline  i n f e r e n c e s  responses f o r  Several  do  i n r e p r o d u c t i v e  p o t e n t i a l l y  i s  1983;  i n which  maturation  breeding  t h e w i n t e r  others  t h e  i n t h e o v e r w i n t e r i n g  Fraser  throughout  d i f f e r e n c e s l e a s t  c o s t s  i n  r e s u l t e d  and  winter  m o r t a l i t y  delayed  of  c o n d i t i o n s .  1979) although  developmental  w i t h  c e s s a t i o n  t h e  winter  V i j v e r b e r g  the  The  e f f o r t  a l .  t h e  made  j u v e n i l e  ( S n e l l  a l l o c a t e d  g e n e r a t i o n s ,  r a t e s ,  f e c u n d i t y  strengthen  budget  was  impose  experimental  e t  t h e o v e r w i n t e r i n g  than  a s s o c i a t e d  maintenance  mercedis  j u v e n i l e  r e p r o d u c t i v e  t e m p e r a t u r e s . a d d i t i o n a l  summer  l e s s  Brody  between  t h e  of  s t u d i e s  energy  d i f f e r e n c e  e f f o r t  was  d i f f e r e n c e  t o t a l  t h e  exceeded  other  1983)  s i g n i f i c a n t l y  and  r e p r o d u c t i v e  a d u l t  t h e  subsequent The  1982;  l i f e  e f f o r t  1980).  and  Reznick  d i f f e r e d  by  i n t h i s  1980; Browne  of  on  B e l l  1983;  p r o p o r t i o n  p r e d i c t e d  1974;  c o s t s  r e p r o d u c t i v e  e f f e c t s  a _ l . of  r e p r o d u c t i o n  c u r r e n t  d e l e t e r i o u s  1977; H i r s h f i e l d  F e i f a r e k  that  (Schaeffer  d e m o n s t r a t i o n King  r e q u i r e  i s and  mercedis  and and no that a r e  s e l e c t i o n . r e p r o d u c t i v e  e f f o r t  as t h e  126  p r o p o r t i o n  of  the  animal's  r e p r o d u c t i o n  focus  r e p r o d u c t i v e  e f f o r t .  v a r i e d  by  growth  and  (1)  the  r e p r o d u c t i o n ,  T i n k l e  w i t h  or  coming  1975;  energy  that  (3) from  have  t o t a l  the  account  the  r e p r o d u c t i v e  et.  a  1982).  the  of  c o n s i d e r a b l e  i n t r i n s i c  a l l o c a t e d animals  Thus  i t  1980;  e f f o r t seems  budget  p r i m a r i l y with  t o the and  which  c o n t r o l  e f f o r t  v a r i e s  Browne vary  1982),  w i t h  and  resource  necessary  i n  by  ( H i r s h f i e l d  r e p r o d u c t i v e  of  (2)  budget  Experiments  r e p r o d u c t i o n  do  a l t e r  p r o d u c t i o n  i n c r e a s i n g l y 1980).  ignores  the  f a c t  energy  budgets  s i n c e  t o  r e p r o d u c t i o n  that or  a l l o c a t i o n s  t o  comparing  to  v a r i a t i o n  can  only  a l l o c a t i o n  i n  some  p a r t i t i o n  However animals take  r e p r o d u c t i v e  the  i n t o  t o  of  a l l o c a t e d  appeal  t e m p e r a t u r e s  i d e n t i c a l  l e v e l  p r o d u c t i o n  d i f f e r e n t  ( H i r s h f i e l d  t o t a l  be  between  budget, going  i t s  could  p r o d u c t i o n  maintenance  measurement  p r o p o r t i o n  and  the  t h a t  energy  of  t o  i n c r e a s e  e f f o r t  t o t a l  ( H i r s h f i e l d  given  c o u l d  i n c r e a s e  1983).  a l l o c a t e d  take  l e v e l s  of  e f f o r t .  N e v e r t h e l e s s  growth  the  and  a l .  t o t a l  f i x e d  reducing  budget  of  (Browne  of  a  with  by  which  a l l o c a t i o n  f o r  growth  energy  c o s t s  Moreover,  the  budget  r e p r o d u c t i v e  demonstrated  a v a i l a b i l i t y  energy  theory,  budget  Tuomi  i n t a k e  the  In  a l t e r i n g  t o t a l  energy  mechanisms  r e p r o d u c t i o n  i n c r e a s i n g  r e d u c t i o n  on  t o t a l  come of  as  the  r e p r o d u c t i o n  has  i n  e f f o r t  the  amounts  from  p r o d u c t i o n .  p r o d u c t i o n  between  cases:  medakas  reared  s i m i l a r  amounts  of  r e p r o d u c t i o n  at  higher  t h i s  measure  of  r e p r o d u c t i v e  may  r e q u i r e  very  very  d i f f e r e n t  p r o d u c t i o n  and  at t o t a l  temperatures  d i f f e r e n t  times  of  t o  r e p r o d u c t i o n  e f f o r t t o t a l  accumulate ( H i r s h f i e l d  127  and  T i n k l e The  1975). t h r e e  p r o p o r t i o n constancy weight  of of  on  c o l l e c t e d . years  cost  of  that  energy  a l s o  r e l a t i o n  of  i n c r e a s i n g  q u e s t i o n  of  number mercedis  very in  that  energy  s i z e d  measures  approach  e f f e c t i v e  t h e  young of  would  f e c u n d i t y  of  be  were  does  v a r y t o  t o attempt  and  of  e f f o r t "  of  b e n e f i t  each  assumes  of  e f f e c t i v e  o f f s p r i n g  s u r v i v i n g  on  t h e  i n t e r -  s c h e d u l e s .  energy  p a r t i t i o n e d w i l l  w i n t e r  A l t h o u g h may  u n i t s i n t o  vary  imply  begs  t h e  young  and  w i t h  s i z e  g e n e r a t i o n s  c l u t c h  mass  d i f f e r e n c e  i s not  e f f o r t .  Perhaps  d i r e c t  i s  t h e  r e p r o d u c t i o n  and  t h i s  both  measure  schedule  i n d i v i d u a l s .  body  a l l o c a t e d  " r e p r o d u c t i v e  depends  t h e use  r e p r o d u c t i v e be  -  data  r e l a t i o n  w e i g h t - s p e c i f i c but  i d e n t i c a l  t h e  p r o d u c t i o n  The c l u t c h  weight  c o r r e l a t e  t o  Summer  same  s i z e  s u r v i v o r s h i p  s u r v i v o r s h i p  both  show  when  number  should  that  r e f l e c t  s i n g l e  commitment  young.  d i v i d e  d i f f e r e n t  t h e above  u s e f u l  of  t o  c l e a r l y  f e c u n d i t y ,  t h e a g e - s p e c i f i c  and N.  how  of  reasonable  and  same  y e a r s .  measures  f e c u n d i t y  e n e r g e t i c  of  between  l i f e t i m e  f e c u n d i t y  e f f e c t i v e  body  t h e  r e p r o d u c t i o n .  t h e c l u t c h  1978  -  i n a  t o  f a c t s  and  attempts  i s a  i s , t h e  g r e a t e r  how  vary  r e p r o d u c t i o n  t h e  1)  weight  a l l o c a t e  p r o d u c t i o n )  d u r i n g  Each  E f f e c t i v e  ( i . e . ,  (chapter  t h e above  that  breed.  t h e  from  t h e p r o p o r t i o n  a l l o c a t i o n  f e c u n d i t y ,  a r i s e s  i n v a r i a n t  of  mercedis (29%)  s i z e  that  N.  p r o d u c t i o n  c l u t c h  so  of  weight  s a t i s f a c t o r y .  and  an  was  must  N e i t h e r  to  body  The  r e p r o d u c t i o n  w h o l l y  r a t i o  t o t a l  r e l a t i o n  between  t h e i r  t h e  and  dependence s i z e  g e n e r a t i o n s  of i n t o  r e f l e c t e d  measurements  a  more of  t h e  1 28  The  p r e d i c t i o n s  frequency N.  of  mercedis  produced  breeding  p r o p o r t i o n  5  of  t h e females  many  females  broad  s i z e  some  m u l t i p l e  which  range  o f  i n  dichotomy  Energy  g r a v i d  more  m o r t a l i t y i s  The  However  two  i n  t h e  t o change  . i t  a d u l t  only  i s  between  females a  and  t h e  small h i g h t h a t  The  r a t h e r t h a t  although  t h e  m o r t a l i t y  o c c u r r e d between n o t  d a t a .  suggest  g e n e r a t i o n  t h e  my  u n l i k e l y  f i e l d  disagreement  d e t e r m i n i n g  broods  t h e  only  c l u t c h e s .  exceeding  g e n e r a t i o n s  w i t h  i t e r o p a r i t y :  make  i n each  r e g a r d i n g  t e s t  m u l t i p l e  p r e d i c t e d  summer  a r e u n l i k e l y  of  than  females  o c c u r r e d  mechanisms  energy  mercedis  t h e leakage  suggested  energy  capable  t o  i n t h e f i e l d  g e n e r a t i o n .  l i f e t i m e  Neomysis  a q u a t i c  d i f f i c u l t  produced  produce  breeding  t h e  theory  f o r  i n  t h e  theory  and  unexpected:  t h e  s e m e l p a r i t y / i t e r o p a r i t y s u c c e s s i v e  g e n e r a t i o n s .  Budgets  The  t h a t  animals budget.  m e t a b o l i c  s o l u b l e  t h e may  12)  be  a  o r g a n i c  l a r g e  (1976)  C a l l i o p i u s u s e .  and and  The  underestimate  of  have  e x c r e t i o n  products  carbon  mercedis  of  budgets  (Table  Dagg  end  amphipod  m e t a b o l i c N.  o f  h i s t o r y  i n t h e l a b o r a t o r y .  a d u l t s  j u v e n i l e  p h y s i o l o g i c a l  the  on  would  o v e r w i n t e r i n g  for  broods  i t e r o p a r i t y  nature  a r e  t o  r a t e s  c o n d i t i o n s  l i f e  i s p h y s i o l o g i c a l l y  up  m o r t a l i t y  of  t h e  n o t been  d i s s o l v e d  f r a c t i o n  s e p a r a t e l y  (36%) measured  t h e leakage  extent t h e  of  leakage t o t o t a l  g e n e r a t i o n s  a d j u s t e d  compounds.  of  found  t h r e e  which  account  Hargrave organic of  (1971)  matter  t h e i r  by  t o t a l  t h e e x c r e t i o n  o r g a n i c  t o be  t o  o f  compounds  about t h e  a s s i m i l a t e d  30%  o f i n  o f t h e  budgets energy  f o r i s  129  d i f f i c u l t  t o e s t a b l i s h .  Hargrave  " e x c r e t i o n "  of  organic  the  of  d i s s o l v e d  leakage  r e p r e s e n t s  30%  underestimate The 14)  c a n  s i z e  and  Table  of  be  compounds  energy  t o those  bracket  of o f  by N.  of  w t a r r  t s b e o  t o t a l data:  h  budget  ( J )  i n t e r s p e c i f i c  i n t h e p r o p o r t i o n  e l o n q a t a  (Fager  and  r e p r o d u c t i v e T h e i l a c k e r  may  12 17)  m e r c e d i s .  Mysis Lake  and whose  There  r e l i c t a Stoney  i s  r a t e s  16.4%  71 . 7 % 13.1% 3.4%  65.6% 12.0% 5.9% 994.2  e f f o r t  h i g h e r  1968).  As  (17.2%)  and  The  energy  f o r  l a r g e ,  Lake  11.8%  i n t e r p o p u l a t i o n  t h e t o t a l  were  C l u t t e r  1971).  and  of  Metamysidopsis  and  (Table  M e t a m y s i d o p s i s e l o n g a t a ( C l u t t e r and T h e i l a c k e r M y s i s r e l i c t a (Lasenby and L a n g f o r d 1972)  M o r t a l i t y  l a r g e  a l s o  budgets  (Tables  992.3  84.8  r e p r o d u c t i o n .  a d u l t s  I f  15%.  mysids N.  m y s i d .  mysids  energy  mercedis  Char  17.2% 6.4% 50.0% 9.2% 17.2%  o l i sm t i o n duct i o n  c o n s i d e r a b l e 17.2%)  i n  t h e  17. L i f e t i m e a l l o c a t i o n of energy (%) f o r f e m a l e s of s e v e r a l p o p u l a t i o n s of m y s i d s . E x c r e t i o n i s e s t i m a t e d as 18% of m e t a b o l i c heat l o s s ( E l l i o t t and Davison 1975).  Metamysidopsi s e l o n q a t a gro mol m e t e x c rep  about  other  those  r e p o r t e d  u n i d e n t i f i e d  t h e above  energy  budgets  an  (1968)  compounds  t h e m e t a b o l i s m ,  compared  l o n g e v i t y  by  o r g a n i c  t h e a s s i m i l a t e d  l i f e t i m e  and Geen  t h e  j u v e n i l e s  than  t h e mysid  M y s i s  t o  s h o r t - l i v e d  i t e r o p a r o u s  l o n g - l i v e d  ( 3 . 4 -  a l l o c a t e d  s m a l l ,  p r e d i c t e d , was  v a r i a t i o n  budget  f o r  1971)  f o r  made  a  ( C l u t t e r  r e l i c t a  made  130  low  r e p r o d u c t i v e  i t e r o p a r o u s the  a r c t i c  (Lasenby  and  Lasenby  1983)  c o s t s ,  and mg  Lake  when  w h i l e were  Metamysidopsis to  young  devoted t h e  ( C h i l d r e s s  p r e d i c t e d  f o r G.  g e n e r a l l y  l e s s  i n  of  22%  ingens  Lake  inqens  shunted  o f  those  of  of.  s i z e  produced  p o p u l a t i o n ) .  t o t a l  p o p u l a t i o n s The  p r o d u c t i o n  t o  a l l o c a t e d  26%.  f o r  N.  m e r c e d i s .  i t sl i f e t i m e  of  e f f o r t  compared.  p r o d u c t i o n  l o n g - l i v e d  (7  y r ) ,  i t s p r o d u c t i o n  S e m e l p a r i t y  j u v e n i l e l a t e r  was  g i a n t ,  61%  r a t e s  maintenance  r e l i c t a  p o p u l a t i o n  1983).  s i n c e  M.  measured  42%  of  r e p r o d u c t i v e  i t s  t h e 29%  P r i c e  egg  p r o d u c t i o n of  e f f o r t  ( B e r r i l l a n d  i n c r e a s e d  s m a l l e r  t h e semelparous  and  than  which  temperate  a l l o c a t e d  w h i l e  Gnathophausia  t o  slowed  f o r t h e temperate  Stoney  s i m i l a r  p h y s i o l o g i c a l l y  r e p r o d u c t i v e from  d i f f e r e n c e s  and  elongata  r e p r o d u c t i o n  a b y s s a l  mg  was  t e m p e r a t u r e s  much  t h e a l l o c a t i o n  p o p u l a t i o n  values  food,  0.20  a r c t i c  r e p r o d u c t i o n These  t o  lower  low  t h e  (1.7 times)  t h e  d i s a p p e a r e d  low  and  p a r t l y  under  from  compared  l a r g e  between  Char  and/or p a r t l y  The  r e s u l t e d  development  as  The  (3.4-5.9%)  1971).  p o p u l a t i o n  growth  (0.12  e f f o r t s  was  m o r t a l i t y  i n s t a r s  i n t o  c o r r e c t l y  r a t e s  ( C h i l d r e s s  were  and  P r i c e  1978). These  data  agree  organisms  w i l l  i t e r o p a r o u s  organisms  great  range  noteworthy.  o f The  p h y s i o l o g i c a l l y of  poor  s u r v i v a l  w i t h  show  lower  shown  that  r e p r o d u c t i v e and by  e f f o r t s  i t e r o p a r o u s of  p r e d i c t i o n  g r e a t e r  ( H i r s h f i e l d  e f f o r t  i s  t h e  T i n k l e t h e  made  One  e f f o r t s  1975);  by  s p e c i e s  s p e c i e s that  semelparous  might  than  however  i t e r o p a r o u s  b u t e f f e c t i v e l y  i n t e r e s t .  semelparous  expect  t h e i s a r e  because a  low  131  p r o b a b i l i t y  of  r e p r o d u c t i v e Temporal favour  mercedis  N.  m i r a b i l i s  r e c a l c u l a t e d  0.19).  a  than  a  were  i n  f a c t o r s  r e l a t i v e l y  from  was  1 7 ) . s i m i l a r  i n v e r t e b r a t e s  those  of  t o  but such  a f f e c t i n g  t h e two  of  h i g h  Shushkina Table  c l u t c h  favour  h i g h  i s n o t t h e  c a s e .  s u r v i v o r s h i p  might  s t r a t e g y .  e f f i c i e n c i e s  (0.43,  f o r  second  i n s e m e l p a r i t y  "bet-hedging"  g e n e r a t i o n  e f f i c i e n c y g r e a t e r  as  n e t energy  N.  w i n t e r  e f f o r t  v a r i a b i l i t y  such  The  p r o d u c i n g  t h e  b u t were  1972) The  and  t o  t h e  r e l i c t a  g e n e r a t i o n s  s i m i l a r M.  n e t energy  (0.32, M.  summer  Banse  t o those  e l o n q a t a e f f i c i e n c y  average  n e t  of  (0.41, of t h e energy  1979) b u t was  p o p u l a t i o n s  of  (0.15  much and  132  CHAPTER  3.  LIFE  HISTORY  VARIATION  Neomysis  IN  mercedis  I n t r o d u c t  S p a t i a l l y h i s t o r y the  t r a i t s  s u r v i v a l  The  separated  t h e p r o d u c t i o n  f e c u n d i t y  s t r o n g l y  by  p r e d a t o r s , h a b i t a t s  food  near  f i s h  e t  h a b i t a t s changes the  a l . on  i n f i s h term  mysids t o  N.  a r e p o s s i b l e m e r c e d i s ,  s e l e c t i o n I  and have  p o p u l a t i o n  on  mercedis  and  t h e r e l a t i v e  t h e t o t e s t  t h e  downstream  u p r i v e r  s i t e s  v a r i a t i o n i n  e t a_l.  m i g r a t i n g  d i f f e r e n c e s  i n  b e n t h i c  magnitudes  seasonal 1978) and  t o  i n l i f e  e s t u a r i n e  i n  u p r i v e r  o f minimal  (Northcote  f i s h  i n both  reduced  salmon  of  i s  Freshwater  o f  a t  because  young  and  Seasonal  t o be  i s  d i s t r i b u t i o n  h a b i t a t s  higher  freshwater  of  1 ) .  abundance  1976, 1978).  (Futuyma  determined  o f N.  t h e  h a b i t a t s .  abundance  (chapter  a f f e c t  mercedis  t h e s u r v i v a l  p e r i p h y t o n  j u v e n i l e  between  flow  of  C o n s e q u e n t l y ,  N.  t h e mysid's  estuary  o f  between  mysid  e s t u a r i n e  composition  depending  gene  of  i s expected  residence  l i f e  d i r e c t l y  d i f f e r  t h e  salmon  s l i g h t l y  t h e  species  and  and  1975,  i n t h e e s t u a r y .  t r a i t s  w h i l e  crops  lower  i n t h e i r  d i v e r g e  which  water  from  salmon  compared  short  s i t e s  of  a r e  p r e d a t i o n  l i m i t  standing  may  young  l e v e l s  d i f f e r  j u v e n i l e  of  j u v e n i l e  OF  HOLMES  f a c t o r s  a v a i l a b i l i t y  River  i n v e r t e b r a t e s  (Northcote  food  POPULATION  ion  b r a c k i s h  t h e upstream  f a c t o r s :  m i g r a t i n g  on  e s p e c i a l l y  Fraser  above  t h e  dependent  i n f l u e n c e d  the  of  FRESHWATER  p o p u l a t i o n s  i f e n v i r o n m e n t a l  o r  A  r e a r i n g h i s t o r y  p o p u l a t i o n s of  n a t u r a l  1979). l i f e  h i s t o r y  t h e e x i s t e n c e  o f  a  and  freshwater nature  of  133  l i f e  h i s t o r y  p o p u l a t i o n s . d i f f e r e n c e s enzyme  v a r i a t i o n I  have  a l s o  l i f e  which  h i s t o r y  of  S i t e  The was  and  l i f e  s t u d i e d  River  h i s t o r y  a t Nicomen  l o c a t e d  122°10'W,  d i s t r i b u t i o n of  C o l l e c t i o n s 1977  t o March  Nearshore samples  were  t o  (about  m)  c o n d u c t i v i t y preserved, the  t i d a l a t  a s  were  s o r t e d ,  e s t u a r i n e  t h e  f o r  d e t e c t a b l e d i f f e r e n c e s  p o p u l a t i o n s .  taken 4-5  from  1976).  l i m i t The  was  a t  m  V e r t i c a l a t  analyzed  s i t e  s a l t  from  p r o f i l e s  w h i l e  was  a r e o f o f  d e s c r i b e d  mysid's  i s l o c a t e d  1  depth  Fraser  ( a t about  t h e  t h e  m i d c h a n n e l . as  mercedis  t h e  wedge.  by  d e p t h .  midchannel  done small  w e l l  September  s t r a t i f i e d  Sampling which  of  o f  of  sampling 0.5-1  N.  t h e e s t u a r y  i n c h a p t e r  m.  of  sidechannel  p e n e t r a t i o n  that  measured  p o p u l a t i o n .  g e n e t i c  p o p u l a t i o n  upstream  f l u c t u a t i o n s  and  p o p u l a t i o n s  Methods  l a r g e  d e s c r i b e d  t h e s i t e .  were  a  e_t a l .  c o l l e c t e d a t  reference 0.5  t h e  1979 e x c e p t  samples  and  between  u p r i v e r  maximum  made  suggest  freshwater  km  near  t h e  were  a  70  (Northcote  two  e s t u a r i n e  Methods  Slough,  about  49°08'N)  upstream  o f  and  e l e c t r o p h o r e t i c a l l y  d i f f e r e n c e s  C o l l e c t ion  t h e  might  M a t e r i a l s  Study  freshwater  examined  i n t h e f r e q u e n c i e s  polymorphisms  u n d e r l y i n g  between  without amplitude  temperature Samples i n chapter  and were  1 f o r  . 1 3 4  E l e c t r o p h o r e s i s  in  Mysids  c o l l e c t e d  December  1977 a t  polymorphisms gel and  16  at  Nicomen  Slough  and  mid-May  1978  l o c i  (Appendix  e l e c t r o p h o r e s i s . p r o c e s s e d  as  I n d i v i d u a l  d e c r i b e d  examined  f o r each  compared  between  i n  a n i m a l .  and were  6)  F r e q u e n c i e s  Woodward assayed  using  whole  P a r k i n s o n  a t  f o r  enzyme  h o r i z o n t a l  a n i m a l s  were  (1981). of  I s l a n d  homogenized  A l l 16  enzyme  s t a r c h  l o c i  were  v a r i a n t s  were  p o p u l a t i o n s .  R e s u l t s  The b r o a d l y given  t o  . b r e e d i n g  a t  Woodward l a t e  appear  u n t i l e a r l y  matured  i n t o  which  the  few  1978;  m a j o r i t y a t  females the  d e t a i l s  a r e  however. the  s p r i n g  were  found  S2  d i d  were  not  found  g e n e r a t i o n  o v e r w i n t e r e d Slough  components  o n s h o r e - o f f s h o r e s i z e .  was  j u v e n i l e s  Nicomen  midchannel  i n  i n  females  of  Slough  noted  l a t e r  g r a v i d  p o r t i o n  t h e  and  and  were  g r a v i d  p o p u l a t i o n  s e a s o n a l  i n abundance  p o p u l a t i o n ;  newly-hatched  s m a l l  mysid  Nicomen  commenced  A l t h o u g h  a  nearshore  suggested  d i f f e r e d  Slough  f i r s t  only  at  d i f f e r e n c e s  May.  i n  mercedis e s t u a r i n e  Very  t h e  of  bred  s e p a r a t e d f l u c t u a t i o n s  and  end  Second,  t h e  Two  I s l a n d .  immatures.  N.  Nicomen  November,  and  of  5.  a t  A p r i l the  of  that  Appendix  before  u n t i l  h i s t o r y  s i m i l a r  i n  F i r s t , than  l i f e  movement  as was  whose and  1 35 3.5  T  1 5I  1—i  1  I—I  1  1—i  1—I  1  S O N D J F M A M J J 1B77  1—I—I—I  1  1—I  l  A S O N D J F M  1978  1979  F i g u r e 29a. The mean s i z e ( ± 1 SE) of adult female Neomysis mercedis at Nicomen Slough, 1977-1979 . (A) = midchannel, ( O ) = nearshore. Note the abrupt decrease in mean body s i z e i n e a r l y summer.  3.5  "i  3.0  1.5-1—I  1  1  1  1—i  1  1  1—i  S O N D J F M A M J 1977  1  1  1  1  1  1  1—, c  J A S O N D J 1978  FM 1979  F i g u r e 29b. The f i r s t d e c i l e s i z e of adult female Neomysis mercedis at Nicomen Slough, 1977-1979 . ( A ) ~ midchannel, ( o ) = nearshore. The f i r s t d e c i l e s i z e approximates the s i z e at m a t u r i t y . Note the seasonal changes in s i z e at m a t u r i t y .  3.0  1  -  5  J 0  1  1  1  •  5  10  15  20  Temperature (C)  Figure 29c. The e f f e c t s of ambient temperatures on the s i z e at maturity of female Neomysis mercedis at Nicomen Slough ( O ) and Woodward Island ( A ) . Note t h a t , in the s p r i n g , females at Nicomen Slough mature at Smaller body s i z e than do females at Woodward I s l a n d at the same ambient temperatures (upper c e n t r e ) .  136  Body  Size  The  mean  Nicomen of  Slough  a d u l t  s p r i n g  s i z e (Figure  females  breeding again  from  abrupt  2.6  mm  as  a  segment  of  matured  a t m a t u r i t y  the  e s t u a r i n e  than  Egg  and  c o n t r a s t  55nq  n = 93) the  of  t h e  t h e mean a t  d i s t r i b u t i o n d r y  /ug w h i c h  e x p o n e n t i a l l y -  a t  mean  l e n g t h  s i z e  a t m a t u r i t y  i n t h e  be  b u t  a  smaller  about  1 ) .  t o  t h a t  t h e s p r i n g  The  waters  e x p e c t e d .  s i m i l a r  and  presumably  midchannel  1)  s i z e  from  (chapter  would  a t  r e s u l t e d  summer,  very  The of  b r e e d i n g  s i z e  (2.6  mm)  ( F i g u r e 2 9 c ) .  e s t u a r i n e  s i z e  of  Nicomen was  weight.  eggs  unimodal  The  mean  eggs with  s i z e  Woodward  female  body  was  c a r r i e d  with  egg  a t  r e l a t i o n  p o p u l a t i o n ,  Slough  i s i n d i s t i n g u i s h a b l e  l a r g e - t y p e  f e c u n d i t y  as  females  t h e summer  i n mean  changes  was  (chapter  p o p u l a t i o n  d u r i n g  c o o l e r  s i z e ,  The  uropod  i n t h e  t h e  matured  mm  s i z e  mm  t h e summer  Slough  t o  s e a s o n a l l y  frequency  l a r g e r  mm  changes  2.0  a d u l t  Fecundity  d i s t r i b u t i o n change  2.2  t h e  i n  p o p u l a t i o n  t h e e s t a u r i n e  In  to  during  2.8  temperature  p o p u l a t i o n  a t Nicomen  S i z e  t o about  s l i g h t l y  s i z e  females  i n  of  s e a s o n a l l y .  from  The  decrease  t o seasonal  a  v a r i e d  t o about  i n t h e f a l l .  t h e  a t  29a,b)  a t m a t u r i t y  decreased  i n t h e s p r i n g response  s i z e  generation  increased an  and  a  range  i d e n t i c a l  from  about  44.4  (Figure  weight  31a) of  The 35yg  (SE=±0.51,  Fecundity  t o that  d i d not  30a,b).  t h e average  I s l a n d . s i z e  was  frequency  females  (Figure  weight  from  by  t h e  t h e  of  increased and  t h e  e s t u a r i n e  137  50  t  Spring 1978  >» o c  40 "  cr o 2  30 - -  S  20  CP 3  w  tL  10 "  20  30  40  60  50  Egg Weight (ug) F i g u r e  3 0 a . The frequency d i s t r i b u t i o n at Nicomen Slough i n s p r i n g 1978.  of  mean e g g (n=78).  weights  50 T Summer 1978 >» o c  40  a  30 -•  •  CD 3  CD  CD  20 •-  O  k.  CD  a.  10 -•  0  1  1  1  20  30  1  1  1  40  50  1  1  60  Egg Weight (ug)  F i g u r e  3 0 b . The frequency d i s t r i b u t i o n a t N i c o m e n s l o u g h i n summer 1978.  of  mean e g g (n=13).  weights  138  l a r g e  egg  C l u t c h  a n i m a l s  p>0.05).  Weight  The Slough  d r y  weight  increased  slope  of  that  of  heavier  Table  (Ancova,  the  a t  18.  weight  e s t u a r i n e  the  c l u t c h e s  e x p o n e n t i a l l y  c l u t c h  the  of  -  egg  with  body  body  s i z e  p o p u l a t i o n ,  f r e s h w a t e r  s i t e  Comparison of s i z e - a output and female c o n Slough) and e s t u a r i n e of Neomysis mercedis s i g n i f i c a n t l y a t the been log-transformed Woodward I s l a n d 1978 1978 l a r g e egg type, var  c a r r i e d  females  a t  s i z e  (Figure  3 1 b ) .  r e l a t i o n  but  (Table  by  was  c l u t c h e s  1 8 ) .  The  the  were  t o t a l  Nicomen The  same  as  about  20%  weight  d j u s t e d measures of r e p r o d u c t i v e d i t i o n i n f r e s h w a t e r (Nicomen (Woodward I s l a n d ) p o p u l a t i o n s . B r a c k e t t e d groups do not d i f f e r 5% p r o b a b i l i t y l e v e l . Data have to homogenize v a r i a n c e s . 1= small egg type, 2=Woodward I s l a n d 3=Nicomen Slough 1978.  i a b l e  groupings  weight  1  <  ( 2 ,  3)  s i z e - a d j u s t e d : a)  body  s i z e  e s t u a r i n e of  the  b)  c l u t c h  c)  body  d)  t o t a l  weight  weight weight  r e l a t i o n s s i t e s  c l u t c h  r e l a t i o n s t o t a l  f e c u n d i t y  were  weight  (Table  were  i d e n t i c a l  1 8 ) .  W i t h i n  weight the  -  same.  f o r Nicomen  body  s i z e  each and  (2,  3)  <  1  (1,  2)  <  3  (2,  3)  <  1  (1,  2,  a t  t h e  3)  f r e s h w a t e r  p o p u l a t i o n t o t a l  C l u t c h  weights  were  Slough  females  but  weight about were  t h e 21%  only  and  slopes  body  s i z e  of  t h e  about  16%  1 39  100  5 4— 1  1  1  2  3  1 4  1  5  Uropod Length (mm) Figure  31a. The r e l a t i o n between f e c u n d i t y a n d f e m a l e s i z e a t Nicomen S l o u g h , 1978.  2.0  E  body  t  1.0 +  3 o  02 1  , 2  , 3  , , 4  5  Uropod Length (mm) Figure  31b. female  The r e l a t i o n s h i p between c l u t c h w e i g h t body s i z e a t Nicomen S l o u g h , 1978.  and  1 40  of  the  t o t a l  weight  f o r  Woodward  I s l a n d  females  i n  1978.  E l e c t r o p h o r e s i s  E l e c t r o p h o r e t i c a l l y found  at  only  dehydrogenase one  a l l e l e  l o c u s  v a r i a n t s  two  (MDH)  homozygous  while  the  v a r i a n t s  h e t e r o z y g o u s  a t  a  d i m e r i c  v a r i a n t s t e s t ,  three  (Table  The frequency of Neomysis mercedis  I s l a n d Slough  PGI .  Nicomen  at  a  d i m e r i c  Slough  showed  a l l e l e d i d  not  d i f f e r  p r o t e i n  v a r i a n t s  BC  2  41  13  1  42  12  p r o t e i n  v a r i a n t s  AA  AB  17  3  16  4  to two three  and  l o c u s .  BB  The f r e q u e n c y o f MDH Neomysis mercedis .  I s l a n d  19)  M a l t a s e  two The  between  p>0.05).  AB  Woodward  genotype  one  were  corresponded  homozygous  (chi-squared  (b)  which  t o  the  Nicomen  s u r v e y e d .  corresponded  of  Woodward  l o c i  (PGI)  f r e q u e n c i e s  (a)  two  16  polymorphisms  isomerase  genotypes  19.  the  enzyme  phosphoglucose  h e t e r o z y g o u s  T a b l e  of  showed  and  which  p o p u l a t i o n s  d e t e c t a b l e  i n  i n  141  D i s c u s s i o n  The  most  between Slough  the and  the  i n c r e a s e  s i t e  d e s p i t e  the  i n  biomass to  d u r i n g  environments; the  adjusted food  mass  r e l a t i o n  s i t e .  s i z e ,  The the  smaller  s i z e s and  Slough.  or  t o t a l  s i t e s ,  s i t e ,  would  be  the  weight  the Food  d i f f e r e n c e s .  d i d age  c o s t s  e l e v a t e d ,  -  would  s i z e  Slough  e f f e c t s I n t r i n s i c  not  mature  f r e s h w a t e r waters  weight would  was  at or for  between  the  S i z e -  -  the  at  the  the  longer the  i n  body  mature  i n v a r i a n t  matured  s i m i l a r  at  on  a l t h o u g h  d i f f e r e n c e s  e a r l i e r  account  d i f f e r e n c e s  u p r i v e r  p r o d u c t i o n .  t o t a l  g e n e r a t i o n s was  and  s a l i n e  animals  p o p u l a t i o n  m a t u r i t y d i d  the  s i z e - a d j u s t e d  were  r e f l e c t  the  r e l a t i o n  e q u i v a l e n t at  or  between  u n l i k e l y  a l t e r  and  developmental  the  and  are  e i t h e r  somatic  e s t u a r i n e  f r e s h  merely  freshwater  d i f f e r e n c e s i n  the  D i f f e r e n c e s  a  s i t e s  might  a l s o  then  a n i m a l s  Nicomen as  so,  from  Nicomen was  the  between  both of  I s l a n d at  t r a i t s  at  w e i g h t s .  the  p r o d u c t i o n  might  I f  between  e f f e c t s  osmoregulatory  c l u t c h  l a r g e r  seem  d i r e c t  t o t a l  i n t r i n s i c  when  mercedis  mass  d i f f e r e n c e s  summer  of  a v a i l a b i l i t y .  s i z e a  the  thus  c l u t c h  from  h i s t o r y  Woodward  r e s u l t  m a i n t a i n e d  p a r t i t i o n i n g  d i f f e r e n t i a l  or  However,  were  at  N.  p r o d u c t i o n  c o u l d  freshwater  weights  p o p u l a t i o n s  equal  l i f e  of  s i z e - a d j u s t e d  of  p o p u l a t i o n s .  c l u t c h  p o p u l a t i o n  s i z e - a d j u s t e d  i d e n t i c a l  r e p r o d u c t i v e  the  the  i n  p o p u l a t i o n  e s t u a r i n e  a l l o c a t i o n  s e n s i t i v i t y  d i f f e r e n c e  freshwater  20%  in  n o t i c e a b l e  .  at  r i c h e r between same  or  e s t u a r i n e at  Nicomen observed  p o p u l a t i o n s  thus  p o s s i b l e . However  no  d i f f e r e n c e s  i n  genotype  f r e q u e n c i e s  were  found  142  between  the  allozymes the  p o p u l a t i o n s  were  surveyed.  p o p u l a t i o n s  p o r t i o n that  of  the  the  are  w i t h  was  however,  1976;  have Doyle  s e l e c t i o n l i m i t e d  a q u a t i c  been  shown  to  (Doyle should  energy  c o n t r i b u t i o n  of  the  p o p u l a t i o n s ,  as  A l t h o u g h e n e r g e t i c did  not  the  the  or  to  s i n c e  1954;  B i r d  1980;  e v o l u t i o n a r y  a v a i l a b i l i t y  (see  u n l i k e l y  be  to  Mysis  Cody  a  f o l l o w i n g  above,  Slough  the  i n  Strong  1972;  Mashiko of  e f f e c t s  important  s i z e  that  organism's  maximized  and  l e v e l s  c h a p t e r i n  the  Geneticbetween  made  a  of 1). the  i n c r e a s e d .  known  and  have  l a r g e r  f e c u n d i t y  a l s o  are  Corkett  f a c t o r  argued  s i z e - a d j u s t e d  temperature, of  been  p a t t e r n s  s i z e  1982)  has  u n r e a s o n a b l e .  egg  egg  McLaren  an  p o p u l a t i o n  mean  and  h i s t o r y  g e n e r a t i o n s .  not  r e p r o d u c t i o n ,  l i f e  (1966)  a l l o c a t i o n are  (Furst  change  which  were  e s t e r a s e  1972;  of  manner  evidence  of  c e r t a i n  genetic  small  p o p u l a t i o n s .  r e l i c t a  a l l o c a t i o n i n  the  (Strong  1981a).  d i s c u s s i o n , an  i n  a  p a t t e r n s  f r e q u e n c i e s  r a p i d  energy  p h y s i o l o g i c a l e f f e c t s the  and  to  d i f f e r e n c e s  (Hynes and  i n  between  between  only  d i r e c t  a l l o c a t i o n  h e r i t a b l e  the  Nicomen  i n c r e a s e ,  Dolah  to  i n  p o s t u l a t e d  I n t e r p o p u l a t i o n  Van  i n  the  resources  investment  crustaceans  be  genotype  d i f f e r e n c e s  no  was  c r u s t a c e a n s ,  Hunte  r e s u l t  or  there  found  1981a,b)  and  time  based  been  other  Hunte  s i n c e  energy  i n  In  and  documented  i n  d e t e c t a b l e  d i f f e r e n c e s  p o s s i b l e ,  d i f f e r e n t i a t i o n  isozymes  t r a i t s  very  d i f f e r e n c e s  d i f f e r e n c e s  1969).  i n t r i n s i c  surveyed,  I n t e r p o p u l a t i o n  Nyman  e l e c t r o p h o r e c t i c a l l y  Although  g e n e t i c  have,  16  s t i l l  genome  observed  a s s o c i a t e d  when  i n  McLaren been  food,  many 1978;  a t t r i b u t e d  and  s a l i n i t y  p r e d a t i o n  and  food  Temperature  i s  present  case  s i n c e  1 43  temperature were  d i f f e r e n c e s  very  s l i g h t  I d e n t i c a l  eggs  d i d  have  e x p e r i e n c e d  been  Freshwater  produce  l a r g e r  (Hynes  1954).  modify  The  Although  freshwater  the  and  d i f f e r e n t i a t i o n  represent  The  other  suggest  s i t e s  s i n c e  food  d e s p i t e  t h e  of  l a r g e r which  a t  e i t h e r  a r e known  water  v a r i a t i o n  t h a t  g r e a t l y .  that  eggs  c r u s t a c e a n s  which  s i t e s  animals  l a r g e  b r a c k i s h  y e a r - t o - y e a r  .  p r o d u c t i o n  c a r r i e d  animals  d i f f e r e d  imply  freshwater  of  e s t u a r i n e  p o p u l a t i o n s  i n t h e egg  e x p e r i e n c e d  other  t o  f a c t o r s  s i z e  s a l i n e  must  a l s o  s i z e .  e s t u a r i e s  1980).  s i z e s  between  s i z e .  adjacent  1)  and  weights  environments  d i f f e r e n c e s  between g e n e t i c  by  e s t u a r i n e  (chapter  egg  induced  However,  s p r i n g - b r e e d i n g  c o n d i t i o n s  egg  than  egg  g r e a t l y  i n mean  p o p u l a t i o n s  eggs  when  t o t a l  d i f f e r  freshwater  s i t e .  of  not  d i f f e r e n c e s  c o u l d  t h e u p r i v e r  i n t h e s p r i n g  s i z e - a d j u s t e d  a v a i l a b i l i t y observed  between  and g e n e t i c  c l a i m  d i f f e r e n c e s  i n  environmental  a d j a c e n t between  i n l i f e  h i s t o r y  a r e thought  i n l i f e  there  was  t o  t r a i t s  of  mercedis  N.  between  evidence  promote  ( L e v i n t o n  h i s t o r y  l i t t l e  N e v e r t h e l e s s , t r a i t s  e x i s t i n g  p o p u l a t i o n s  p o p u l a t i o n s  a d a p t a t i o n s ,  p r o b a b l e .  waters  adjacent  t h e d i f f e r e n c e s e s t u a r i n e  c o n d i t i o n s  between may t o  make  there  were  obvious  t h e two  p o p u l a t i o n s .  144  GENERAL A  s t r i k i n g  v a r i a b i l i t y m y s i d .  i n  The  f i r s t l y  a  appears  t o  f e a t u r e  s e a s o n a l r e s u l t  v a r i a t i o n  v a r i a t i o n  l a r g e l y  r a t e s ,  mass. v a r i a t i o n  Both  o f  l e v e l s  p r o d u c t i o n  and in  as  a t  m a t u r i t y  p o t e n t i a l l y  i n  t h e  p r e d a t o r y  f i s h e s  mechanism  through  The l a r g e l y  v a r i a t i o n i n  t h e o r y .  C u r r e n t  decreased  i n c r e a s e d  the  a t  age  l i f e  i n an  that  t h e  f e c u n d i t y  e f f o r t ,  budget,  measured  when  m a t u r i t y expanding l i f e  t h e  a d u l t  and  h i s t o r y  on  as  brood  s i z e  between-  and  egg  s i z e .  r e l a t i v e such  a r e  h e r i t a b l e  Seasonal  v a r i a t i o n  r e s u l t  c o m p o s i t i o n food  t r a i t s  from  s e a s o n a l  and  s i z e  l e v e l s ,  seen  p r e d i c t i o n s  e f f o r t and as  r e p r o d u c t i v e  i n N. o f  of  p r o v i d e  imposed  a  c o s t s  a  e f f o r t  These  were  c h a r a c t e r i s t i c s  of  h i s t o r y  i n terms  of  t h e  h i g h ;  o c c u r r e d  r e s u l t s  i s  o f  s u r v i v o r s h i p ;  p r o p o r t i o n r a t e s  mercedis  l i f e  decreased  m o r t a l i t y  p o p u l a t i o n .  which  c o u l d a c t .  h i s t o r y  w i t h  i s  Furthermore,  which  t h e  concommitant  t h e  commonly  c a p i t a  s e l e c t i o n  r e p r o d u c t i v e  f u t u r e  r e p r o d u c t i v e  r a t e s ,  p e r  such  s e l e c t i o n .  s p e c i e s  i n  i n l i f e  agreement  t o  i t a  i n f l u e n c e  f e c u n d i t y  by  temperature  f e c u n d i t y  and  t h e  There  c o n s i d e r a b l e  i n d i v i d u a l s .  abundance,  which  as  i s  m a t u r i t y ,  o f  w i t h  by  s u b j e c t  and  i s  such  a t  t r a i t s  s t r o n g l y  s i z e - d i f f e r e n t i a l m o r t a l i t y  changes  influence  there  w i l l  l e v e l s .  t h e s i z e  c a r r i e s  mercedis  i s e x h i b i t e d  two  h i s t o r y  i n t r a i t s  o f f s p r i n g  s i z e  thus  which l i f e  v a r i a t i o n  o f  i n  N.  which  a t  t h e  Secondly  i n d i v i d u a l  t r a i t s  from  and  of  t r a i t s  m a n i f e s t s  i n s i z e - r e l a t e d  c l u t c h  t h e b i o l o g y  h i s t o r y  v a r i a b i l i t y  p h y s i o l o g i c a l  and  l i f e  of  DISCUSSION  energy  and  both  e a r l i e r  support organisms  t h e  i n view  c a n  be  1 45  c o n s i d e r e d n a t u r a l  as  an  s e t  of  w i t h  the  observed  t h e o r e t i c a l  v a r i a t i o n  p r e d i c t i o n s ,  p r o b a b l y  p h e n o t y p i c  p l a s t i c i t y  v a r i a t i o n  rather  genetic  r e s u l t  i s  i m p l i c i t  i n  n e c e s s a r i l y  l i f e  h i s t o r y  c o n t r o l l e d  temperature determine  s i z e  and  age  t r a i t s  and  i n  e n v i r o n m e n t a l  w i t h  food  p r o v i d e s  c o u l d  on  the  responses  t o  being  d e c r e a s i n g  a  of  as  a l t e r growth  the  s h i f t s  a d a p t i v e :  from  i n  g e n e r a t i o n s  the The  was  g r e a t e r  of  i n  i n  may  i t s e l f  i n  which  Thus, s i z e would  the  increase  s i z e  p h y s i o l o g i c a l at  t r a i t .  at  m a t u r i t y  through  the  that  mercedis  increase of  the  changes as  w e l l  population of  f o r  the  the  of  of  m a t u r i t y  increase  s t r u c t u r e  dependences  w i t h  s e l e c t i o n  development  rate  i n  between  m o r t a l i t y  p o s s e s s i n g  N.  which  v a r i a t i o n  of  i n  a The  rates  rates  observed  be  s i z e - d i f f e r e n t i a l  the  i n  T h i s  assumptions  c o r r e l a t i o n  temperature  temperature  than  i n  r a t e s .  v a r i a t i o n  and  the  the  through  r e s u l t e d  was  s e l e c t i o n .  increase  p o p u l a t i o n  s i z e  p o t e n t i a l  to  s y n c h r o n i z e s  the  change  temperature  p h y s i o l o g i c a l  i n d i v i d u a l  of  w i t h  observed  t r a i t s  polymorphism.  p l a s t i c i t y  mechanism  s e a s o n a l  m a t u r a t i o n the  The  which  r a t e  as  v a r i a t i o n  and  a  f e c u n d i t y  s u r v i v o r s h i p . and  seasonal  the  size-dependent through  m a t u r i t y  f u n c t i o n  Temperature-dependent i n f l u e n c e s  the  p h y s i o l o g i c a l  temperature  s u r v i v o r s h i p  in  of  of  from  i n c o n s i s t e n t  subject  h i s t o r y  mechanism  such  t r a i t  temperatures  o p e r a t e  change  l e v e l s .  i n c r e a s i n g . s i z e  a l s o  r e s u l t i n g  l i f e  r e s u l t i n g  since  at  i n  the  t h e o r y  dependence  h i s t o r y  m o r t a l i t y  than  not  g e n e t i c a l l y  l i f e  a d a p t a t i o n s  s e l e c t i o n .  A l t h o u g h agreed  i n t e g r a t e d  the  which  rates  c l e a r l y the  of are  summer  o v e r w i n t e r i n g  146  g e n e r a t i o n  because  g e n e r a t i o n  length  of  a  than  p r o p o r t i o n a l l y i n  t h e  g r e a t e r  change  concommitant  i n t h e  r e d u c t i o n  i n  f e c u n d i t y . I n t e r p o p u l a t i o n f e c u n d i t y  and  d i f f e r e n c e s  c l u t c h  g e n e t i c a l l y  based  c o n d i t i o n s ,  a l t h o u g h  demonstrated. l i f e summer  breeding  lakes  (Furst  food  of  a r e and  l e v e l s  food of  t h e  such or  temperature  f o r  u n e x p l a i n e d N e v e r t h e l e s s q u a l i t a t i v e m e r c e d i s .  by  l i f e p a t t e r n  may  explained  A  p o r t i o n  i n N.  by  v a r i a t i o n  h i s t o r y of  s i z e ,  theory  l i f e  were  s p e c i f i c a l l y  as of  d i f f e r e n c e s has  t h e  both  t h e  i n  l i f e there  c l u t c h  l i f e  e f f e c t s  of  i n t e r -  and  h i s t o r y  Although  remains mass,  i n  c o n d i t i o n s  h i s t o r y  s u c c e s s f u l l y  h i s t o r y  Swedish  l i f e  t h e v a r y i n g  i n  sympatric  i n some  i n d i v i d u a l s .  i n  v a r i a t i o n ,  i n brood  e n v i r o n m e n t a l  d i f f e r e n c e s  mercedis  r e f l e c t  e x p e r i e n c e d  s i z e  v a r i a t i o n  seen  mass  i n t r a p o p u l a t i o n  accounted  N.  c l u t c h  been  r e p r e s e n t  .  which  populations  i n t e r p o p u l a t i o n  1980).  v a r i a t i o n  s p e c i f i c  r e l i c t a  s i z e - a d j u s t e d may  i n t e r p o p u l a t i o n  breeding  have  as  s i z e  d i f f e r e n c e s  i n M y s i s  Other  such  egg  t o  based  w i n t e r  (Morgan  as  i n  genetic  known  r e l i c t a  i n t r a - p o p u l a t i o n t r a i t s  no  1972). M.  and  a d a p t a t i o n s  G e n e t i c a l l y  h i s t o r i e s  h i s t o r i e s  mass  i n t r a i t s  and  t r a i t s  much i s  c o n s i d e r a b l e egg  accounts  v a r i a t i o n  of  s i z e . f o r t h e  seen  i n  147  Appendix  j_: The  O u t m i g r a t i o n  o f  Neomysis  mercedis  from  T i d a l  Channels  The reaches using 0.47  p a t t e r n of  a mm  which  o f  t h e t i d a l v e r t i c a l  mesh)  d r a i n e d  o u t m i g r a t i o n channel  s e r i e s  p l a c e d i n t o  a t  o f  s i t e  (Figure  i n t e r v a l s  c o n t i n u a l l y  four  from  D r i f t h i g h  night  of  11  January  1978  Water  d e p t h ,  s u r f a c e  c u r r e n t  measured  a t  p e r i o d .  Samples  d e s c r i b e d In mysids  b e g i n n i n g  were  both  t h e  e m i g r a t e d  c h a n n e l .  from  dropped  The  speed below  p u l s e  much  i n  d r i f t  much  m  was  a t  X  30  and of  t h e  r e g u l a r  t i d e  15  0.5  on  January  f o r m a l i n  0.5  and  h  h  t h e 1978.  temperature each  cm,  channel  a l t e r n a t e  low  on  upper  examined  ( 3 0 cm  above  t o  mid-day  10%  t h e  s e c o n d a r y ,  60  water  t h e  was  s e r i e s ,  t h e d r i f t  r a t e s  lower  than  those  These  r e s u l t s  A1)  were  sampling  counted  as  T h i s  i n - w h i c h i n t h e  i n t h e n i g h t t i m e  imply  that  1  as  flow  sample  showed  i m m e d i a t e l y peak  t h e channel  daytime  m-s"  was  i n  l a r g e  before  were  n e t s  than  t h e  p r e s e n t  d i d n o t d r a i n  s e r i e s  t h e  t o t h e  a  n o t  of  abrupt  i n t h e upper  samples  second  p u l s e  an  c o n f i n i n g  caught  i n t e r v a l  s m a l l  0.2  i n t h e night  n i g h t  i n t h e  a  w i t h  t o about  h e i g h t ,  l a r g e r  t h e  s e r i e s ,  c o n c u r r e n t l y  t h e mysids  c o m p l e t e l y dewatered. daytime  time  ( F i g u r e  of  Moreover,  i n c r e a s e  n i g h t  p r o p o r t i o n  sample.  Indeed,  i n  t h e bank  the  t h e  a  t h e end  t h e c h a n n e l  t h i s  in  a t  and  and  d u r i n g  channel  of  speed,  p r e s e r v e d  day  i n c u r r e n t  l e v e l  day  samplers  sampled  s l a c k  and  receded  about  was  from  above.  i n c r e a s e water  t h e  d r i f t  c h a n n e l  1 ) .  mysids  t h e t i d e  t h e c o n f l u e n c e  t h e main  sampling  as  o f  d r y .  g e n e r a l l y  s e r i e s .  o u t m i g r a t i o n  i s a  p a s s i v e  response  1 48  0.20  40  T  1 1 January  1978 (Night) T  T  20:00  21:00  22:00  23:00  24:00  1000  1:00  Time (h)  15 January 0.20  1978 (Day)  40T  T  1 000  ft  /  •  0.15  •  =  -• 800  30E o  •o m a  >  0.10  +  •  0.06  600  | c  400  -  °>'.. O  - 20 + a e Q  o  o  m  u  10  •o  200  0  c  IO  t  J1 1:00  12:00  13:00  14:00  15:00  16:00  Time (h)  F i g u r e A1. T h e e m i g r a t i o n r a t e (numbers p e r 0.5 h ) o f N e o m y s i s m e r c e d i s ' on f a l l i n g t i d e s a t n i g h t a n d m i d - d a y ~. ( • ) = w a t e r d e p t h i n dm, ( o ) = c u r r e n t s p e e d i n m*s , (—) = the v e r t i c a l s e r i e s of d r i f t net catches w i t h t h e t o p c u r v e b e i n g t h e bottom n e t . _ 1  149  to  p h y s i c a l  mechanism. swimming Much  of  t r a n s p o r t I  d r a i n i n g  of  the  i n  t h e  w i t h and  s t u d i e s r e l a t e d  a t  of  of  s i z e  nets  mechanical  net  t o  by an  d r i f t  through  The  was  a v o i d  (0.47  mm)  t o  was  mysid  assumed  r e t a i n above  t h e  t r u e  a  (2)  net  (1)  mesh s i z e  i n  mercedis  Net  both  because  because  t h e my  of  gear  t h e  c o n c u r r e n t  must d r i f t  t h e  c u r r e n t  that  mysids  c l a s s e s d r y .  was of  two  of  t h e  c a t c h e s  t h e  pass n e t  on  s l e d - t o w e d  t h e  of  of  r e l a t i v e  d i s t r i b u t i o n  s i z e  d r a i n e d  t h e  r a t h e r  s i z e  t h e  h i g h  of  c o n s i s t e n t N.  and  by  p o p u l a t i o n  s i n c e :  s m a l l e s t  t h e d r i f t  as  that  t h e  of  s i z e ,  c o n s t r i c t i o n  s u f f i c i e n t l y  t h e n e t ;  by  d i s t r i b u t i o n  a t  t h e  d r i f t i n g  t h e Sled-Towed  mysids  o b t a i n e d  Much  i s  determined  t h e  when  mysids  a v o i d a n c e  I  of  i s r e a s o n a b l e  c o n s t r i c t i o n not  gear  c h a n n e l s .  channel  This  and  1963).  s e l e c t i v e  s i z e  p l a c e d  I  of  t h e  o u t .  responses  Herman  s i z e d  sample  l a t t e r  d r a i n e d .  channel  t h e  t h e e n t i r e  c o u l d  the  d i f f e r e n t  u n b i a s e d  t h i s  be  r e t e n t i o n .  samplers  s e l e c t i v e ;  c u r r e n t  1969;  d i f f e r e n t i a l  day.  b e h a v i o r a l  water  t h e  more  a  upstream  of  low  of  were  i n t h e  and  t o  a t  bottom  S e l e c t i v i t y  known  comparing  which  channel  the  a r e  of  p o p u l a t i o n . of  The  mesh  c a t c h a b i l i t y  l i g h t  out  t h e a n i m a l s  There  than  (Heubach  2:  based  o c c a s i o n s  t h e  mysids  Appendix  column.  being  o r i e n t e d  swept  j u s t  t h e  than  be  being  f o r c e s  a l o n g  n i g h t  r a t h e r t o  o c c u r r e d  channel  water  column  Towed  w h i l e  o c c u r r e d  t h e  water  mysids  e m i g r a t i o n  o u t m i g r a t i o n than  observed  v i g o u r o u s l y t h e  p r o c e s s e s  channel as  t h e  was  non-  speed (and  small mysids;  a t  f i s h ! ) enough and  (3)  150  The  d r i f t  samples  taken.  d e s c r i b e d  compared p r o p o r t i o n  uropod  The  1.5  were  h  before  low  p r e s e r v e d  t i d e  and  and  s l e d  a n a l y s e d  as  of  N.  samples  mercedis  mysids,  i n  and  the  i n  (Figure s l e d  became  the A2).  samples  roughly  s l e d  samples  The  increased  constant  as  r e l a t i v e with  above  the  1.0  mm  l e n g t h .  one  gives  a  at  s i z e s  constancy  of  mysids  caught  are  observed  measure  of  I  n o r m a l i z e d  have above  the  the thus  s i z e - f r e q u e n c y be  i n c o r p o r a t e  noted both  that  the  1.0  r e l a t i v e by  c a t c h a b i l i t i e s  should  about  u n d e r - r e p r e s e n t e d  d r i f t  c a t c h a b i l i t i e s .  The  were  the  the  This  to  set  samples  mysids to  of  was  p r e v i o u s l y .  Small  s i z e  net  r e l a t i v e  mm  the  on  sampler  obtained  i n  t h e i r  were  used  b e h a v i o r a l  and  for  c a t c h a b i l i t y mechanical  gear  that  that  t r u e to  absolute  c a t c h a b i 1 i t i e s  assumption  i n d i c a t e d  d i s t r i b u t i o n s these  than  r e l a t i v e  the  p r o p o r t i o n s  s l e d  rather  the  the l a r g e  p r o p o r t i o n s . c o r r e c t  s e l e c t i o n .  c o r r e c t i o n s s e l e c t i o n .  the I t w i l l  151  2.Or  U r o p o d Length  (mm)  F i g u r e A2. The r e l a t i v e c a t c h a b i l i t y o f N e o m y s i s m e r c e d i s o f d i f f e r e n t s i z e s by t h e s l e d - t o w e d n e t .  1 52  Appendix  3_:  The  Accuracy  Est imated  Lynch s p e c i f i c  (1983)  the  a c c u r a c y . method  Here  to  a  wi t h  the  rates  examine  s e r i e s  t e c h n i q u e  of  the  M o r t a l i t y  Rates  A l g o r i t h m  p e r i o d i c  the  of  Lynch  a  from  p r e c i s i o n I  S i z e - s p e c i f i e  presented  m o r t a l i t y  c o n s i d e r e d  of  to  estimate  size-abundance e s t i m a t e s  a l g o r i t h m  for  s i m u l a t e d  d a t a .  but  b i a s  by  s i z e -  not  He t h e i r  a p p l y i n g  p o p u l a t i o n s  of  the known  c h a r a c t e r i s t i c s . If  the  s p e c i f i e d  over  m o r t a l i t y and  which to  as  i n  e q u a t i o n s  m o r t a l i t y  r a t e s  m o r t a l i t y  rate  m(i)  = -  of  were for  [ l n {  i s i s  the set  a  next  a  of  the  i - t h  N ( i , 0 )  the  +  +  f l u x  the  T h i s  unknown, to  a  [G(i-1,1) } of  a n i m a l s  + -  the  expected the  w i l l  depend  w e l l  as  on  of  to  a  m ( i ) ,  by  given  of  the  leads in  the  set  of  assuming  s i z e  i.e.,  on  animals  equations  f u n c t i o n s then  the  s i t u a t i o n  c o n s i d e r e d ,  c l a s s  be  s i z e - s p e c i f i c  number  problem  r e c r u i t s  G ( i , i + 2 ) ]  of  as  s i m u l t a n e o u s  c l a s s  abundance  c l a s s  can  However,  c l a s s  c l a s s .  s i n g l e  s i z e  the  p e r i o d .  s i z e  s i z e  c l a s s e s  comparing  a c t u a l  of  i n  then  the  the  s i z e  by  g i v e n  reduced  the  the  the  i n  of  " s l o w l y " - v a r y i n g  [ G ( i , i + 1 )  N ( i , t )  G(i,x+1)  rate  that  end  determine i n t o  t ,  c a l c u l a t e d  p r e c e d i n g  Lynch  m o r t a l i t y  between  i n t e r v a l  the  the  grow  r a t e s .  approximated  and  at  under-determined  the  where  be  animals  these  to  independent  [1]  can  of  rate  survive  m o r t a l i t y  that  sampling  m(i)  number  r a t e ,  an  animals  abundance  m o r t a l i t y  growth  of  the  rate  observed  expected the  f l u x  c l a s s  that  s i z e .  the The  becomes  G ( i - 2 , i ) ] • e x p ( - m ( i ) • t / 2 ) l n { N ( i , t ) } ] i - t h  from  s i z e  c l a s s  i  /  t  c l a s s to  at  time  c l a s s  t i+1  1 53  over  the  i n t e r v a l  expressions c l a s s e s ,  f o r t h e which  intersample The of  The  terms  m o r t a l i t y  I  of  estimate  e r r o r s  t h e  (2)  c l a s s e s , of  a  t o  Lynch's  which of  s e r i e s  t h e  of  s p e c i f i e d  represent  an  c l a s s e s  a t  f o r 20  two  s i z e  f i r s t  during  between  s i z e -  temperature-dependent  mercedis  and  f i n a l  s i z e  t h e G  c l a s s e s  were  m o r t a l i t y  i n a c c u r a c i e s [1].  adjusted  were  t h e  i n t o  a p p r o x i m a t i o n  t h e c l a s s  t h e  a b i l i t y  change  time  of  c l a s s e s  t o i - t h  w i l l  r e l a t i v e  depend t o  and  may  t h e  of  m o r t a l i t y  i n t e r v a l ,  s i z e  t h e  t h e magnitude  (1)  was  i n equation rates  of  t h e  r a t e s  (4)  i n f l u e n c e  from  i n t h e a p p r o x i m a t i o n  known  a p p l i e d .  u n i t  t h e t h e  c l a s s e s  of  determined determined growth  The [1]  so  t h e used  true i n  t o  d i s t r i b u t i o n . d a i l y  d a i l y  t o  f u n c t i o n  that  i n i t i a l  i n t e r v a l s  f u n c t i o n  same  p o p u l a t i o n An  u n i t  5  m o r t a l i t y  Each  i n t e r v a l s .  f o r m o r t a l i t y  d i s t r i b u t i o n .  terms  upon  t r a n s i t i o n s  of  e x p e r i m e n t a l l y  T r a n s i t i o n s and  depend  populations  a l g o r i t h m  was  equation  gives  estimate.  d i s t r i b u t i o n  estimated  Lynch  G(i-2,i)]«exp(-m(i)•t/2)  i n t o  adjacent  t h e m o r t a l i t y  + of  rate  (3)  simulated  c a l c u l a t e  t h e  recruitment  Therefore  [1].  s i z e  true  by  i n t h i s  t r a n s i t i o n s  100  N.  m o r t a l i t y .  of  w i l l  [ G ( i - 1,i)  of  abundances  c o n s i s t e d  .affected  t h e  i n equation  s i z e  accuracy  rates  time-pattern  of  r a t e ,  r e l a t i v e  r a t e s  of  e f f e c t s  t h e magnitude  between  of  p e r i o d .  t h e a c t u a l  c l a s s .  other  be  approximation  represent  on  i n t h e absence  m o r t a l i t y  may  a c c u r a c y  t h e  t  using measured y i e l d was  d e v i a t i o n s values t h e  used of  r e f l e c t  d e r i v a t i o n  t h e f o r t h e t o t h e only of  1 54  The f a c t o r s  e f f e c t s l i s t e d  frequency the  of  m o r t a l i t y  which the  i n t e r v a l .  The  c a l c u l a t i o n  of  (2)  m i d d l e  d i s t r i b u t i o n  an  by  of  t h e t h e  of  m o r t a l i t y  r a t e s ,  c l a s s e s ,  and  t h e  m o r t a l i t y  and on  an  t h e  were  (1)  a  d i s t r i b u t i o n  c l a s s .  o.  Change  c o n s t a n t i n c r e a s i n g  U-shaped  The using  10 50  t r u e  Lynch's  s l i g h t l y  10 50  as  1  Time I n t e r v a l 5 day 1 1 day day  95-96  76-86  67-100  92-99  76-85 72-81  63-95 53-82  78-85 73-92  63-105 53-126  94-96  m o r t a l i t y p r o c e d u r e . t h e  M o r t a l i t y 1 day'  true  rates The  a r e  P o i s s o n e s t i m a t e d  0.5  1  day  92-100  rate  A1-A3.  t h e  day"  1  Time I n t e r v a l 5 day 1 1 day  96  of  i n T a b l e s  Rate  c o n s i s t e n t l y  a c c u r a c y  m o r t a l i t y  v a l u e s  The  t o  c e n t r e d  R a t i o s of (estimated•100% / a c t u a l ) m o r t a l i t y r a t e s c a l c u l a t e d f o r a u n i f o r m i n i t i a l s i z e - f r e q u e n c y d i s t r i b u t i o n using t h e Lynch a l g o r i t h m .  M o r t a l i t y P a t t e r n  true  the  u n i f o r m  Table  0.1  t h e  a p p r o x i m a t i o n  a p p r o x i m a t e l y  f i r s t  i n  d i s t r i b u t i o n s ,  r a t e s  (a) UNIFORM DISTRIBUTION  t o  of  m o r t a l i t y  A1.  compared  Gaussian  (3)  t h e  r a t e ,  change  d u r a t i o n  s i z e - f r e q u e n c y of  four s i z e -  percentage  importance  t h e  i n i t i a l  the  a p p r o x i m a t e l y  c e n t r e d  e s t i m a t e s  v a r y i n g  magnitude  i n i t i a l  the  rate  s i z e ,  r e l a t i v e  c l a s s ,  a r e  examined  w i t h  between  t h e  m o r t a l i t y  t h e  m o r t a l i t y  d e t e r m i n e d  t h e  were  r a t e s  d i s t r i b u t i o n , on  above  the  d i s t r i b u t i o n ,  p a t t e r n  sampling  on  82-90  66-100  80-89  63-95 51-81  82-89 74-94  63-105 52-122  u n d e r e s t i m a t e d  e s t i m a t e  i n c r e a s e d ,  i n c r e a s e d presumably  1 55  Table  A2.  (b)  R a t i o s of (estimated•100% / a c t u a l ) m o r t a l i t y r a t e s c a l c u l a t e d f o r a Gaussian i n i t i a l s i z e - f r e q u e n c y d i s t r i b u t i o n using t h e Lynch a l g o r i t h m .  GAUSSIAN  M o r t a l i t y  DISTRIBUTION  0.1  %  M o r t a l i t y p a t t e r n  Change  constant  t h e  r e l a t i v e l y t h e  63-97  67-91  53-90  10 50  89-99  75-92  63-103 53-115  67-93  smaller  were  r e l a t i v e of  Lynch's  magnitude  of  t h e  e r r o r  the  d i r e c t i o n the  of  e s t i m a t e .  estimate same  was  t h e  Lynch's under  t h e  t o  t h e  numbers  estimate  other  term as  s i z e  c l a s s e s  change  i n m(i)  between  decreased  i n magnitude between  accuracy m o r t a l i t y  c o n d i t i o n s  of  the  terms  66-100  78-94  63-97  when  f o r which  numbers  w i t h  time  c l a s s e s ;  as  g e n e r a l , d i f f e r e n c e  c l a s s e s  m ( i )  that The  However,  t o  [ 1 ] ,  a c c u r a t e  c l a s s .  In  i-1  became  the  percentage  adjacent  adjacent  e s t i m a t o r  i n t o  i n c r e a s e d .  than  Lynch  i n i t i a l  i n c r e a s e d .  from  term  l e a s t '  s h a r p l y  the  63-103 52- 1 1 4  i n equation  t h e  w i t h  growing  adjacent  l a r g e r  80-94  78-95 69-98  85-100  decreased  i n c r e a s e d  m ( i )  Time I n t e r v a l 5 day 1 1 day  91-99  d i s t r i b u t i o n s ,  approximation  I f  day  1  51-89  f o r c l a s s e s  the  estimate  p r o p o r t i o n  i n c r e a s e d  Poisson  t o  1  day"  G ( i - 2 , i ) ] • e x p ( - m ( i ) • t / 2 )  obtained  accuracy  between  +  compared  and  were  m(i)  66-100  77-92  e s t i m a t e s  i n  77-92  85-99  Gaussian  small  0.5  50  [ G ( i -1,i)  Rate  1  Time I n t e r v a l 5 day 1 1 day  10  U-shaped  For  day  91-99  i n c r e a s i n g  because  1  day'  i ,  the i n the  i n f l u e n c e d then  i n c r e a s e d t h i s  the  by  the the  g e n e r a l l y  e s t i m a t e .  was i t was  g e n e r a l l y designed:  q u i t e  accurate  short  i n t e r v a l s  1 56  Table  A3.  R a t i o s of (estimated•100% / a c t u a l ) m o r t a l i t y r a t e s c a l c u l a t e d f o r a P o i s s o n - l i k e i n i t i a l s i z e - f r e q u e n c y d i s t r i b u t i o n using t h e Lynch a l g o r i t h m .  (c) POISSON DISTRIBUTION  0.1  %  M o r t a l i t y p a t t e r n  1  Change  constant i n c r e a s i n g  true the as  slowly  91-94  74-78  67-100  50  86-92  73-76 65-72  63-96 51-84  10 50  90-94  73-80 65-91  63-105 52-123  changing  m o r t a l i t y sampling t o  m ( i )  rates  i n t e r v a l  make  t r a n s i t i o n s  Time I n t e r v a l 5 day 1 1 day  10  U-shaped  and  day  i n t o  e q u a t i o n [ 1 ] .  M o r t a l i t y 1 d a y "  t h e  f u n c t i o n s .  may and  be  0.5  1  day  86-100  However,  i n t e r - c l a s s  l a r g e  of  r e l a t i v e  1  79-81  66-100  76-80  62-96  76-84 66-93  63-105 51-126  i t i s  c l e a r  u n d e r e s t i m a t e d  t r a n s i t i o n  t h e  d a y "  Time I n t e r v a l 5 day 1 1 day  92-94  s i g n i f i c a n t l y  magnitude  t h e c l a s s  Rate  rates  term  which  t o  t h e other  a r e  that when such  r e p r e s e n t s terms  i n  1 57  Appendix  4^: T h e  E f f e c t s  of  Egg  S i z e  on  Rates  of  P o p u l a t i o n  t h e  rate  Increase  The  e f f e c t s  growth,  r ,  (McLaren  of  can  egg  be  D  by  Equation  a  [1] can  be  [1/D]  {  =  •  m  time  t o m a t u r i t y . i n  dependence  t h e  of  i n  The  i n t e r v a l  g1 t h e  then about (FLP)  The  f o l l o w i n g  p o p u l a t i o n  a p p r o x i m a t i o n  S1  t h e egg 16% would  S) i s  i s t h e  t h e  number  s u r v i v o r s h i p  of  t o  eggs  m a t u r i t y .  as  l n ( S ) }  e f f e c t s  of  =  [1/D]  •  s i z e  on  rate  over  a r e m a n i f e s t  which  p e r i o d  (-m)  l n ( E ) +  m o r t a l i t y  egg  l e n g t h  development  from  s t a g e =  only  t h e e f f e c t s  o r i g i n a t e s  A p r i l  eggs.  f r e e - l i v i n g  If  S  E  i n s t a n t a n e o u s  t h e egg  mature  Mg)  and  g e n e r a t i o n  g e n e r a t i o n  females  l n ( E •  l e n g t h ,  l n ( E ) +  c o n s i d e r  i n l a t e  (42.5  t h e  of  r e s u l t egg  t h e  through  from  s i z e  and  t h e  through  f e c u n d i t y .  F i r s t  l a i d  •  r e - w r i t t e n  i s t h e average  changes  S1  [1/D]  female,  where  The  =  i s t h e g e n e r a t i o n  produced  changes  using  on  1963): r  r  v a r i a t i o n  examined  [1] where  s i z e  -  e a r l y  May  h a t c h i n g a  The  average  s i z e  •  g e n e r a t i o n  be  about  of  (26.1  h a t c h  2.25  30-35  i s about mg  l e n g t h  eggs  Mg)  about  57  and  i n s t a n t a n e o u s  l n ( 2 . 2 5 had  development 1.16  and  g e n e r a t i o n  which  days  rate  r . a r e  l a t e r .  d a y s .  produce  growth  on  The  9  l a r g e  over  t h e  about  [1/57]  t o  s m a l l  t o m a t u r i t y  a t  i s  from  of  •  0.0261)  o r i g i n a t e d  p e r i o d 35  /  =  40.6  (EDP) days  from  =  0.0782 l a r g e  would and  t h e  be  mg-day'  1  ( 4 2 . 5 Mg)  eggs,  i n c r e a s e d  f r e e - l i v i n g  by  p e r i o d  158  t The  and  with  The  S2  l a i d  i n  l a t e r  at  the  FLP  Thus days  of  The  eggs  small  f o r  l a r g e  •  egg  [ l / g 2 ]  of  days  h a t c h e s e a r l y and  r a t e  57)  eggs  days  (12  12  at  the  12  •  1.16  l a r g e  egg  /  0.0425)  =  /  +  would 47.9)  =  be =  59.9  would  day"  r  =  [1/59.9]  •  ln(12)  =  0.0415  day"  g e n e r a t i o n  l a i d  i n  l a t e l a t e  l a r g e  per  g3  =  h a t c h e s  September A p r i l  at  f e m a l e .  i s about 40.6  eggs  l a r g e  43  days  35  d a y s .  -  The days. The  i n  e a r l y  5.44  per  f e m a l e .  t e m p e r a t u r e s 13.9  days.  •  The  i s  mg-day"  mg  (13.9  days  1  1  w e i g h t ,  small  the  ln(5.44/0.0425)  56.9 eggs.  1  eggs  f o r  small  eggs.  October  from  l a r g e  matures  the  next  and  produces  c a l c u l a t e d  average  =  l a r g e  O c t o b e r ,  Thus  43)  f o r  m i d - l a t e  EDP  f o r  +  EDP  f o r  a t  the  l a r g e  i n s t a n t a n e o u s  about  =  0.0262  25  f i e l d  eggs  w i l l  growth  rate  i s  [1/185]  so  be  0.0437  for  from  days  about  =  W  =  47.9  ln(12)  =  w i l l  be  0.0261)  increase  eggs  0.0981  •  1.16*35  small  r  about  neonates  [1/56.9]  be  f o r  Thus  August  f i e l d  =  temperatures  days  eggs.  l a r g e  the  l e n g t h s  and  be  would  l n ( 2 . 8 9  p o p u l a t i o n  eggs  = 9 2  matures  r  i n  days  e a r l y - m i d  August,  would  young  •  12  of  i n  produces  l n ( 2 . 8 9  The  s p r i n g  91.4  eggs  g e n e r a t i o n  rates  and  [1/43]  l a r g e  50.8  +  i s about  growth  small  =  (35  or  l a r g e  of  0.0425)  t h e r e f o r e  w e i g h t ,  EDP  =  f o r  J u l y  mg  g2  the  =  /  s i z e .  l a t e  EDP  =  are  g e n e r a t i o n  2.89  t  l n ( 2 . 2 5  50.8)  egg  i n s t a n t a n e o u s  The  +  c a l c u l a t e d  that  •  times  (40.6  vary  eggs  The  [ l / g i ]  g e n e r a t i o n  eggs not  =  mg-day'  1  159  The  FLP  of  t The  =  neonates  [1/g3]  g e n e r a t i o n  l a r g e  eggs  v a l u e s  would  and Thus,  and  (35  +  203.6)  0.0142  day"  r  =  •  ln(25)  =  0.0134  days  [1/238.6]  r e s u l t not  d i s t r i b u t i o n  f o r  s m a l l  and  a  i.e.,  by  from  having  f e c u n d i t y  of 14  s m a l l  egg  would  be  eggs  would  would  be  d a y "  have  0.0123  d a y "  l e n g t h  p o p u l a t i o n  i n c r e a s e  t o  of  0.005  S e a s o n a l magnitude  be  be  =  225.6  small  .  The  day"  i n  v a l u e s egg  1  changes  0.0287 be  days  eggs.  f o r  The  q u i t e  l a r g e small  r  r  i n  which the  the  may  S1  eggs eggs. S2  be  and  why  W  the  g e n e r a t i o n  S1  d a y '  /  1  =  1.56  i s  .  The 18.7  females.  only  i f the  and  may  eggs  egg,  Then  the  so  16  eggs of  egg  that  s i z e  r on  r a t e  eggs  of  then  instantaneous  of  m o r t a l i t y a  r  l a r g e  p o t e n t i a l  r a t e  be of  that  so  l i f e t i m e  be  would  producing  Large  d e a t h  s i z e - s p e c i f i c  s i z e  f e c u n d i t y  average  t h e i r  the  =  the  egg  over  same  females  g e n e r a t i o n  e f f e c t s  r e d u c e s  p o s s i b l e ,  the  females  25  than  r e q u i r i n g  h e r i t a b l e .  1.56*12  of  young  l e s s i n  f o r  by  the  s i m u l t a n e o u s  l a r g e  l a r g e  f o r  i n  to  h i g h l y  f e c u n d i t y  of  1  produce  g e n e r a t i o n  f e c u n d i t y 1  t o  females  W  r  a r e  egg  would  .  r i s e  examined  s i z e  would  and  higher r a t e  1  g i v e s  s i z e  r  i n c r e a s e s  g e n e r a t i o n ,  be  egg  a  g e n e r a t i o n  m o r t a l i t y  be  eggs.  can  egg  and  S1  which  females  0.0488  i n  the  given  small  eggs  s l i g h t  l a r g e  h a t c h  =  i n  i n  which  t h i s  f o r  =  e f f e c t s  young.  days  would  days  185)  ln(25)  F e c u n d i t y  0.001  238.6  +  •  weight  r e s u l t  (40.6  =• [ 1 / 2 2 5 . 6 ]  but  S2  =  be  203.6  r  g e n e r a t i o n s  1.56«9  would  =  eggs  be  eggs  bimodal  small  l n (5 . 4 4 / 0 . 0 2 6 1 )  l e n g t h s  l a r g e  egg  •  from  f a c t o r  i s  about  small  egg  r a t e s  of  i n d u c i n g  160  the  observed  egg  s i z e  b:  The  L i f e  Appendix  v a r i a t i o n .  H i s t o r y  of  Neomysis  mercedis  at  Nicomen  Slough  P h y s i c a l  Parameters  Midchannel v a r i e d  l a t e  when  than  s a l i n i t y to  was  100  s e v e r a l Slough  not  at  the  2  1  m  e s t u a r i n e  the  always  the  (Figure  w i n t e r  to  temperatures s i t e  between were  s i t e  1  except  18-20°C were  l a t e  or  A3)  2°C  i n  i n  1-3°C  A p r i l  and  c o o l e r  e a r l y  at f a l l  warmer. a  p u r e l y  f r e s h w a t e r  C o n d u c t i v i t y  a l t h o u g h  throughout  i n  temperatures  degrees  was  temperatures  water  the  measurable.  jumho-cm"  f l u c t u a t i o n s  a t  2°C  bottom  g e n e r a l  than  were  Nicomen  In  water  about  temperatures  Slough  they  from  Midchannel  September.  Nicomen  nearshore  s e a s o n a l l y  midsummer. c o o l e r  and  t h e r e  was  environment;  g e n e r a l l y  were  small  c l o s e  i r r e g u l a r  y e a r .  Abundance  P o p u l a t i o n throughout d e n s i t i e s waters two  autumn. l a t e  the were  than  peaks  f a l l ,  d e n s i t i e s year  of  N.  (Figure  c o n s i d e r a b l y at  the  2  about  6 0 0 « m ~  As  the  d e n s i t i e s  t h e r e  was  a  ,  A 4 ) . lower  nearshore  of  mercedis  at  For i n  s i t e .  d u r i n g  much  the  of  deeper  Nearshore  the  d e c l i n e d  i n c r e a s e  30-40 the  i n  and  i n  s h a r p l y the  f o l d y e a r ,  midchannel  d e n s i t i e s  midsummer  nearshore  c o r r e s p o n d i n g  f l u c t u a t e d  showed e a r l y i n  the  midchannel  161  0  1  1  O  1  N 1977  Figure  5  1  D  J  1—I  F  M  1  1  1  A  M  J  1  1  1  1  J A S O N  1  1  1—|  1979  A3. Bottom water t e m p e r a t u r e s a t m i d c h a n n e l a t Im d e p t h ( o ) a t Nicomen S l o u g h f r o m 1977 -  1000  1—i  D J . F M A  1978  ( o ) and 1979.  T  1978 Figure  1  1979  A4. P o p u l a t i o n d e n s i t i e s (#.nr ) a t the nearshore ( o ) and m i d c h a n n e l ( o ) s a m p l i n g s i t e s a t Nicomen S l o u g h 1977 - 1979 . J  162  d e n s i t i e s  which  an  o f f s h o r e  low  (about  the  only  2  20'irr )  a  more  i n  mercedis  r e p r e s e n t e d  an  l o c a t i o n s  but  September  while  autumn  i n f l u x  d e n s i t i e s  increased  females  at  moved  appeared t h e r e a f t e r . j u v e n i l e s , May,  and  l a t e  t o May  immatures  J u l y ,  a d u l t  (S1)  and  The was  midchannel  Since  l e t h a l  nearshore temperature may  midchannel summer  have w a t e r s .  at s i t e  low  both i n  u n t i l  s i t e  nearshore  the  May  l a t e the  broad  d a y s .  u n t i l  while  f o r  they  were  mature  J u v e n i l e s  f i r s t  abundance  maximum  female  that  r a p i d l y  s i t e  e a r l y  a d u l t  suggested  r e s p e c t i v e l y  l e n g t h 85  and  young.  at  a  i n  which  i n c r e a s e d  J u l y  m i d - A p r i l  d e n s i t i e s  i n  about  d e n s i t i e s  corresponded  nearshore  from  peaks  showed  and  when  Midchannel  The  remained  t h e i r  generation thus  l a t e  s i t e ,  the  May,  d e n s i t i e s  i n  found  brood  l a t e  d e n s i t y  i n  c o o l e r  nearshore  and  S u c c e s s i v e  mid-August.  generation  the  were  h a b i t a t .  Embryo  midchannel  onshore  and  e a r l y  Nearshore  the  i n  were  A5a). at  upper  abundance  nearshore  v a l u e s .  the  d e n s i t i e s  maximum  t o  at  from  l a t e  d e n s i t y .  the  r e s u l t e d  r a p i d l y .  maximum  change  r a p i d l y  females  (Figure  nearshore  the  to  reached  p r e c i p i t o u s l y  the  November  i n c r e a s e  movement  midchannel  from  midchannel  nearshore  1971),  d e c l i n e  November  approaching  i n c r e a s e d  Egg-bearing  d e c r e a s i n g  and  o f f s h o r e  d e c l i n e d  the  s h a l l o w - w a t e r  were  D e n s i t i e s  from  slowly the  of and  t o  the  the  (Hair  part  began  of  lagged  temperatures  N.  s i m i l a r  o n e - t h i r d  maximum  that  Nearshore  segment  d e c l i n e  water  and  increased  about  midsummer  for  movement.  nearshore  d e n s i t i e s  to  suggested  were  i n  abundance  of  embryos,  seen  (Figures between the  i n  l a t e  A5a,b,c). l a t e  f i r s t  J u l y summer  163  120  3 O N 0 J F M A M J 1977  J  A S O N O  J  1978  F M  1979  2  Figure A5. The densities (number per n r ) of female (a) embryos, (b) juvenile, (c) immature, and adult Neomysis mercedis at Nicomen Slough from 1977 to 1979 .  164  Newly shallow  waters;  abundant of  r e c r u i t e d  i n a d u l t  i m p l i e d to  t h e  that  a t  embryo  t o mysids  m i d c h a n n e l . a d u l t  t h e midchannel  t h e maturing  S1  a t  t h e  were  more  i n i t i a l  pulse  abundant  The  l a t e  midchannel  moved  t o  warmer  much  more  s t r a t u m .  t h e  females  i n t h e  were  A f t e r  females  d e n s i t i e s  rear  J u l y  l o c a t i o n  t h e deeper  waters  breed. The  p o p u l a t i o n  r e l a t i v e l y  h i g h  apparently  embryo  s i t e .  I n mid-September  f i r s t  a t  r a p i d l y as  a t  appeared immature  however,  summer  and  and  than  i n May,  throughout peak  j u v e n i l e  nearshore  b r e e d i n g  a n i m a l s  midchannel  t o a  second  and  peak  t h e  immatures  November  and  both  November-December  abundance  and  d i d  c r a s h e d  (W  embryo  near  j u v e n i l e s  a  two  and  August  i n J u l y  a t  week  t o o v e r w i n t e r  a t  t h e  t h e  t h e  midchannel i n c r e a s e d ,  J u v e n i l e s  l a g .  immatures  d e s p i t e  d e n s i t i e s  s h o r e .  g e n e r a t i o n )  a f t e r  p e r i o d  seen  October then  i n  increased  nearshore Breeding  moved  ceased  o f f s h o r e  p r i m a r i l y  as  s i t e ,  i n  i n t h e  immatures.  Fecundi t y  The  p r o p o r t i o n  c o n s i d e r a b l y females peaks, the  over  c a r r i e d but  d e c l i n e d i m p l i e d The  t h e  c l u t c h e s  D u r i n g  which as that  bred  t h e  d u r i n g  f a l l  increased  t h e g r a v i d  t h e  s p r i n g  f e l l  f i r s t  b r e e d i n g Almost and  t o about p e r i o d ,  moved  s i m i l a r  a l l  0.5  a d u l t  b r e e d i n g throughout  t h e p r o p o r t i o n  i n nearshore onshore  t o  t o  seen  that  v a r i e d  f a l l  i n t h e midchannel  i n c r e a s e d  was  A 6 ) .  b r e e d i n g  females  p a t t e r n  females  ( F i g u r e  b r e e d i n g  t h e p r o p o r t i o n  seasonal  a d u l t  year  t h e p r o p o r t i o n  summer.  females  of  samples  samples,  of and  which  breed. a t  Woodward  165  S O N  D  J  F  M  A  1977 F i g u r e  M  J  J  A  S  O  N  1  l—i—l D J F  1978  M  1979  A6. Seasonal v a r i a t i o n i n the p r o p o r t i o n of g r a v i d a d u l t female Neomysis mercedis at Nicomen S l o u g h , 1977 to 1979 .  4 0  T  CD ca  3 0  +  S O N  D J  F M A M J J  1977 F i g u r e  A7. Seasonal v a r i a t i o n per a d u l t female Neomysis 1977 t o 1979 .  1978  A  S  O  N  D  J  F  M  1979  i n the average number of eggs m e r c e d i s at Nicomen Slough  166  I s l a n d at  except  Slough,  during  t h e peak  midsummer  d e c l i n e  freshwater The  20  5-6  female  t h e  of  females  was  nearshore p r o p o r t i o n  of  female  v e r s u s  both  Woodward  s i t e s  u p r i v e r  animals  e s t u a r i n e  p a r t l y  a t  a  l a r g e r  much  of  t h e year  d e c l i n e r a t i o the  was  i n  t h e  r a t i o  s t r o n g l y  p o p u l a t i o n  d e n s i t y  l a r g e r  but  of  t h e  s i m i l a r  a t  both  This  i n l a t e  There  was,  winter  and  i n favour beginning  of t o  females  i n c r e a s e  one  t h e from  of  matured c o o l e r  breeding. throughout a  s p r i n g . a t  t h e  that  of  however, e a r l y  a t  r e s u l t e d  females  about  per  of  twice  p r o p o r t i o n  f l u c t u a t e d  than  s i m i l a r  because  higher  average  (20 eggs  d i f f e r e n c e  (presumably  i n  higher  lower  f e c u n d i t y  Slough  per  than  The  were  was  t h e  eggs  20%  peak  of  s l i g h l y  F e c u n d i t i e s  t h e Nicomen  A 8 ) .  s i z e  of  s p r i n g  t o  decreased  samples  about  i n t h e  1 ) .  r a t i o  t h e  and  about  d e c l i n e d  females.  breeding  t h e  but  number  s i z e  was  was  smaller  t h e average  f a l l  from  was  t h e The  females  s i z e  skewed  females  extent  of  midchannel  females  that  (Figure  and  midchannel  (chapter  sex  longer  of  A7)  peaks  r e s u l t  3 ) .  t h e  summer  p a r t l y  male:female  a  female).  t h e  was  ( F i g u r e  breeding  i n  t h e  f a c t  and  of  per  during  t h e  temperatures) The  t h e  animals  from  l a t e r  25  and  g r a v i d  female  as  I s l a n d  about  d u r i n g  f a l l  (chapter  Slough  c o n t i n u e d  p r o p o r t i o n  t i m i n g  breeding  of  Nicomen  a d u l t  and  because  and  s i t e s .  h i g h e r  b r e e d i n g  those  l a t e r  higher  The  summer  s l i g h l y  of  per  females  samples  f e c u n d i t y  eggs  s p r i n g  summer-maturing  s l i g h t l y  p e r i o d s .  d u r i n g  p r o p o r t i o n  a  e s t u a r i n e  of  t h e  and  commenced  i n t h e p r o p o r t i o n  and  number  during  about  the  breeding  Nicomen  bred  the  that  g e n e r a l The  time  sex when  i t s winter  167  minimum. Biomass and  waned  180  mg-nr  f l u c t u a t e d  (Figure 2  a t  v a l u e s  o c c u r r e d  v a l u e s  were  A 9 ) .  both  c o n s i d e r a b l y The  the  much  l e s s  midsummer  nearshore  i n w i n t e r  and  than  as  maxima  and  were  t h e  g e n e r a t i o n s were  midchannel  about  c o r r e s p o n d i n g  about  s i t e s . 2  10  mg'irr .  v a l u e s  waxed  a t  Minimum  The t h e  160—  biomass e s t u a r i n e  s i t e . The and  t o t a l  t o t a l  dependent of  N.  l e n g t h (Table  mercedis  Table  weight,  A4.  body  of  N.  A 4 ) .  from  a  Thus,  i n t o  two  the  Nicomen  f e c u n d i t y ,  Slough  compared  i n chapter  were  w i t h  s i z e those  3.  i n  both  l a t e  j u v e n i l e s  i n  the  a r e a s .  the  y e a r .  nearshore  r i s e  A p r i l  p o p u l a t i o n per  t o  i n  the  016) 014) 24) 24) 007)  of  N.  June  nearshore  by  n  99 99 59 61 99  mercedis  p o p u l a t i o n  females  the  and  areas  0. 0. 0. 0. 0.  midchannel  s p r i n g ,  2  r  (0. (0. (0. (0. (0.  The  and  Breeding e a r l y  1 SE  +-  2 .82 2 .74 3 .59 3 .55 0 .96  - o . 564 - 0 . 578 -1 . 54 - 0 . 1 57 0. 725  g e n e r a t i o n s  nearshore  from  b  f r e s h w a t e r  temperatures  o c c u r s of  has  t h e  immatures  water  s i t e  weight,  Summary of s i z e - d e p e n d e n t f u n c t i o n a l r e g r e s s i o n s of the form l o g ( y ) = a + b*log(uropod l e n g t h i n mm) f o r Neomysis mercedis at Nicomen Slough, 1978.  t o t a l weight (mg) body weight (mg) c l u t c h weight (mg) egg number body l e n g t h (mm)  as  a t  r e g r e s s i o n s a r e  e s t u a r i n e  y  Slough  c l u t c h  mercedis  The  the  weight,  274 274 91 89 253  a t  Nicomen  o v e r w i n t e r s  h a b i t a t s . mature  and  o v e r w i n t e r i n g  g i v e s  r i s e  i n e a r l y  t o  summer.  a  As move  animals p u l s e A d u l t s  168  1.5t  cd  1.0"  © cd E  CD U.  ®  0.5  cd  2  0 '  1 1 S O N  1  1 D J  1—I 1 1 1—I 1 1 1 1 1 1 F M A M J J A S O N D J 1978  1977  1—I 1 F M 1979  Figure A8. S e a s o n a l v a r i a t i o n i n the male:female r a t i o of N e o m y s i s m e r c e d i s a t Nicomen S l o u g h 1977 t o 1979 .  500  t  S O N 1977  D J F M A M J  J 1978  A S O N D J F M 1979  Figure A9. S e a s o n a l v a r i a t i o n i n t h e b i o m a s s (mg d r y w e i g h t p e r m ) of N e o m y s i s m e r c e d i s a t Nicomen S l o u q h 1977 t o 1979 . " 2  1 69  mature  a t  p r o g r e s s i v e l y  c o n t i n u e s most  t o  a d u l t s  remain  mysids  (SI  deeper  waters  p o s s i b l y  i n c r e a s e  when  because areas  d e c r e a s e s  s h a r p l y  g e n e r a t i o n  and  i n l a t e  females  move  r e l e a s e d . much  of  t h e  they  of  a t  i n t h e  mature  i n  t h i s  remains  W  and  The  stops  t h e  u n t i l  g e n e r a t i o n  moves  move  i n t o  -  mid  At  where as  p u l s e t h i s  t h e W  i n t h e  abundance of  t h e  of  breeding  time  t o  S1  mature  j u v e n i l e s  temperatures  o f f s h o r e  t h e  August,  p o p u l a t i o n  O c t o b e r .  but  new-born  temperatures  second  i n November  p e r i o d  The  maturation  a  h a b i t a t  but  J u l y  water  temperature  summer  h a b i t a t .  high  e a r l y  t h e  e a r l y  l a t e  d e s p i t e  low  as  shallows  time.  nearshore  Breeding t h e  rear  i n August  t h e  t h i s  midchannel  t h e extremely  September  t o  s i z e s  throughout  generation)  n e a r s h o r e  occurs  i n  smaller  f a l l  a r e and-  overwinter  as  p o p u l a t i o n  of  immatures. The N.  l i f e  mercedis  t h a t  of  two  of  t h r e e .  The  with  females  Slough  a  i n  that were  a t  w h i l e  d e n s i t y  t h e e s t u a r i n e 600'irr  t h e  2  s i t e .  w h i l e  r e s p e c t s  I s l a n d .  e s t u a r i n e  t h e  S2  generation  a t  Nicomen Maximum  those  a t  which,  of  mature  midsummer  t h e  Slough  e s t u a r i n e was  d e n s i t i e s  Woodward  sharp  s i t e  t h e a t  produced  t h e  i n t h e p r o p o r t i o n e l i m i n a t e d  t h e  p o p u l a t i o n  from  u p r i v e r  from  F i r s t ,  a p p a r e n t l y  r e s u l t e d  r e d u c t i o n  t o  Slough t h e  a t  e f f e c t i v e l y  i n s e v e r a l  Woodward  Nicomen  abundance  p o p u l a t i o n  about  a t  d i f f e r e n c e  corresponding  Second,  a t  freshwater  d i f f e r e d  year  concurrent  breeding,  g e n e r a t i o n  than  mercedis  d e c l i n e  t h e  p o p u l a t i o n  p e r  midsummer  s i t e .  N.  of  Slough  generations  produced  c o u p l e d  Nicomen  t h e e s t u a r i n e  p o p u l a t i o n o n l y  a t  h i s t o r y  a t  lower Nicomen  I s l a n d  were  170  2  about  900-1000•m" .  populations  i n  a l l o c a t i o n The  from  i n  N.  suggested  p r e s s u r e ,  S l o u g h . et  r e s u l t  intermedia and  cause  was 1983,  s p r i n g as  h i g h  1984)  predation  and  et  the  as  t o  d i d may  f a l l t o  p r e s s u r e  mercedis  i n  s i z e  b r e e d i n g  i n  the  i n both (chapter  t o  that  N.  the  f a c t o r  food f a l l . N. 2 ) .  t h e  Slough  of  d e c l i n e  i n c r e a s i n g  Nicomen  A l t h o u g h  the  t h e  i n  1982).  p e r i o d  a  and  s i m i l a r  a  be  between  .  a t  p r e d a t i o n  d i f f e r e n c e s  and  3)  was  a _ l .  f i s h  temperature, N.  but  c o l l a p s e  s t r e s s  a d a p t a t i o n s  p r o b a b l y  I s l a n d  from  just  f e c u n d i t y ,  abundance  corresponded  25°C)  i n  d i f f e r e n c e s  (see c h a p t e r  i n  (Toda  d i s c u s s e d  the  energy  midsumer  d e c l i n e  were  m a t u r i t y ,  Woodward  t h e  (above  a_l.  s p r i n g  a l .  a t  intermedia  the  there  v a r i a t i o n  P h y s i o l o g i c a l  between N.  that  could  temperature  at  a s s i m i l a t e d  that  p o p u l a t i o n  Toda  s i z e  seasonal  d i f f e r e d seen  of  the  T h i r d ,  or  seen i n  intermedia  from  of  the and  they  f i s h i n g  very at  high Nicomen  d e c l i n e s . f e c u n d i t y  g e n e r a t i o n s resources The  intermedia  i n  of the  proximate (Toda  e_t  171  Appendix  The  6:  f o l l o w i n g  d e t e c t a b l e  Enzymes  Surveyed  enzymes  were  E l e c t r o p h o r e t i c a l l y  surveyed  Name  ADH  A l c o h o l  AGP  a - g l y c e r o p h o s p h a t e  Fumerase  dehydrogenase dehydrogenase  Fumerase  G6PDH  G l u c o s e  6-phosphate  HK  Hexokinase  IDH  I s o c i t r a t e  dehydrogenase  IDH-NAD  I s o c i t r a t e  dehydrogenase  ( b - d i p h o s p h o p y r i d i n e  dehydrogenase  n u c l e o t i d e  LAP  Leucine  a m i n o p e p t i d a s e  LDH  L a c t a t e  dehydrogenase  MDH  M a l a t e  ME  M a l i c  PEP  dehydrogenase enzyme  Phosphoglucose  PGM  S o r b i t o l  TO  T e t r a z o l i u m attempt  1981)  t o  improve  extent  of  enzyme  MDH  and  P G I ,  been  p o l y m o r p h i c  isomerase  Phosphoglucomutase  SDH  no  b u f f e r )  P e p t i d a s e  PGI  r e l i a b l y  e l e c t r o p h o r e t i c a l l y  v a r i a n t s :  A b b r e v i a t i o n  As  f o r  was  made  polymorphism  b u t  i n t e r p r e t t e d .  other t h e  oxidase  t o modify  t h e r e s o l u t i o n ,  s e v e r a l  dehydrogenase  t h e p r o c e d u r e s  t h e r e s u l t s  i n N.  m e r c e d i s .  enzymes  p a t t e r n s  do  (G6PDH; were  n o t measure I n  IDH;  t o o  (Parkinson  a d d i t i o n PEP)  b l u r r e d  may t o  t h e t o have be  172  References  A n d e r s o n , B.G. 1 9 3 2 . The number o f p r e - a d u l t i n s t a r s , growth, r e l a t i v e growth, and v a r i a t i o n i n Daphn i a magna. B i o l . B u l l . 63:81-98.  Anonymous. 1978. C a l i f o r n i a Department of F i s h and Interagency E c o l o g i c a l Study Program f o r t h e San Joaquin e s t u a r y . S i x t h Annual Rept.  Game. Sacramento-  Armitage, K.B. a n d L.M. L a n d a u . 1982. The e f f e c t s of p h o t o p e r i o d and temperature on growth and r e p r o d u c t i o n o f Daphnia a m b i g u a . Comp. B i o c h e m . P h y s i o l . 71A:137-140.  B a i r d ,  D.C.  1962. E x p e r i m e n t a t i o n :  an  i n t r o d u c t i o n  measurement theory and e x p e r i m e n t a l Inc., Englewood C l i f f s , N . J .  d e s i g n .  t o P r e n t i c e - H a l l  Banner, A.H. 1948. A taxonomic study o f t h e Mysidacea and Euphausiacea (Crustacea) o f t h e n o r t h e a s t e r n P a c i f i c , I I , Mysidacea, from t r i b e M y s i n i through s u b f a m i l y M y s i d e l l i n a e . Trans. Roy. Canad. I n s t . 27:65-125.  p a r t  B a y c h o r o v , V.M. 1979. Reproduction of t h e mysid Paramysis l a c u s t r i s (Crustacea) i n t h e n o r t h e r n and southern zones of i t s i n t r o d u c t i o n . H y d r o b i o l o g l c a l J . 15:29-34.  B e a t t i e , D.M. a n d H. de K r u i j f . 1978. P o p u l a t i o n dynamics and biomass p r o d u c t i o n of Neomysis i n t e g e r (Leach) i n t h e Bergumermeer. Verh. I n t e r n a t . V e r e i n . L i m n o l . 20:25662571 .  B e l l ,  G. 1 9 8 0 . T h e c o s t s o f Am. N a t . 1 1 6 : 4 5 - 7 6 .  B e r r i l l , M. Mysis  r e p r o d u c t i o n  and  t h e i r  consequences.  1969. The embryonic behavior of t h e mysid r e l i c t a . Can. J . Z o o l . 47:1217-1221 .  shrimp,  B e r r i l l , M. a n d D . C . L a s e n b y . 1983. L i f e c y c l e s of t h e f r e s h w a t e r mysid shrimp Mysis r e l i c t a r e a r e d a t two t e m p e r a t u r e s . Trans. Amer. F i s h . S o c . 112:551-553.  173  B o t t r e l l , H.H. 1975. Generation time, l e n g t h of l i f e , i n s t a r d u r a t i o n and frequency of m o u l t i n g , and t h e i r r e l a t i o n s h i p to temperature i n e i g h t s p e c i e s of C l a d o c e r a from the R i v e r Thames, Reading. Oecologia ( B e r l . ) 19:129-140.  B r a m b i l l a , D.J. 1980. Seasonal ch small p o n d D a p h n i a , p. 4 3 8 - 4 Zooplankton Communities, e d U n i v e r s i t y Press o f New Eng  B r a m b i l l a , in a  nges i n s i z e at m a t u r i t y i n 5 i_n E v o l u t i o n a n d Ecology of t e d b y W.C. K e r f o o t . a n d , H a n o v e r , New Hampshire.  D.J. 1982. Seasonal v a r i a t i o n i n egg s i z e and number Daphnia pulex p o p u l a t i o n . H y d r o b i o l o g i a 97:233-248.  B r a t t e g a r d , the  a 5 i l  T.  1974.  Caribbean  A d d i t i o n a l coast  of  Mysidacea  Columbia.  from  S a r s i a .  shallow  water  on  57:47-86.  B r e m e r , P. and J . V i j v e r b e r g . 1982. P r o d u c t i o n , p o p u l a t i o n b i o l o g y , and d i e t of Neomysis i n t e g e r (Leach) i n a shallow F r i s i a n l a k e (the N e t h e r l a n d s ) . H y d r o b i o l o g i a 93:41-51.  B r e t t ,  J.R. 1979. E n v i r o n m e n t a l f a c t o r s in F i s h P h y s i o l o g y V o l . 7, e d i t e d R a n d a l l , and J.R. B r e t t . Academic  B r e t t ,  J.R. and T.D.D. G r o v e s . 1979. P h y s i o l o g i c a l e n e r g e t i c s , p.280-352 rn F i s h P h y s i o l o g y V o l . 7, e d i t e d b y W.S. Hoar, D.J. R a n d a l l , and J.R. B r e t t . Academic P r e s s , New York  Brody,  M.S., M.H. E d g a r , and L.R. Lawlor. 1983. A cost of r e p r o d u c t i o n i n a t e r r e s t i a l isopod. E v o l u t i o n 37:653-655.  Brody,  M.S. and L.R. Lawlor. 1984. Adaptive v a r i a t i o n i n o f f s p r i n g s i z e i n the t e r r e s t i a l isopod A r m a d i l l i d i u m v u l q a r e . Oecologia ( B e r l . ) 61:55-59.  B r o w n e , R.A. 1982. The c o s t s Ecology 63:43-47.  Calow,  P. 1977. metabolic  of  and g r o w t h , p. 599-675. b y W.S. Hoar, D.J. P r e s s , New York  r e p r o d u c t i o n  i n  b r i n e  Ecology, e v o l u t i o n , and e n e r g e t i c s : a a d a p t a t i o n . Adv. Ecol Res. 10:1-62.  shrimp.  study  i n  1 74  Calow,  P. 1979. approach.  The c o s t of r e p r o d u c t i o n B i o l . Rev. 54:23-40.  C a n n o n , H.G. amd S.M. Manton. 1927. a mysid c r u s t a c e a n , Hemimysis E d i n . 55:219-253.  C a r l i s l e ,  D.B.  and  C r u s t a c e a n s .  F.  Knowles.  Cambridge  1959.  -  a  p h y s i o l o g i c a l  On the feeding mechanism of lamornae. T r a n s . Roy. Soc.  Endocrine  U n i v e r s i t y  P r e s s ,  C o n t r o l  i n  Cambridge.  C a s w e l l , H. 1983. Phenotypic p l a s t i c i t y i n l i f e - h i s t o r y t r a i t s : demographic e f f e c t s and e v o l u t i o n a r y c o n s e q u e n c e s . Amer. Z o o l . 23:35-46.  C h e c k l e y , D.M. 1980. Food l i m i t a t i o n of egg p r o d u c t i o n by marine, p l a n k t o n i c copepod i n the sea o f f southern C a l i f o r n i a . L i m n o l . Oceanogr. 25:991-998.  C h i l d r e b L s  s a o t  s t p r  , J . J h y p e l a h o g a s t u c t u r e  . and g i c c r i d a e . Mar  C h i l d r e b L M  s a o a  s t p r  , J . J . h y p e l a g h o g a s t r ine B i o  M.H. P r u s t a c ) . I. ine B i  a  r i c e . 1978. Growth rate of the e a n Gnathophausia ingens (Mysidacea: Dimensional growth and p o p u l a t i o n o l o g y 50:47-62.  a n d M.H. P r i c e . 1983. Growth rate of the i c c r u s t a c e a n Gnathophausia ingens (Mysidacea: i d a e ) . I I . Accumulation of m a t e r i a l and energy. l o g y 76:165-177.  C l u t t e r , R . I . a n d G.H. T h e i l a c k e r . 1971. E c o l o g i c a l e f f i c i e n c y of a p e l a g i c m y s i d shrimp: e s t i m a t e s from growth, energy budget, and m o r t a l i t y s t u d i e s . F i s h e r y B u l l . 69:93-115.  C l u t t e r , R . I . Monogr.  a n d M. A n r a k u . 1968. Avoidance of oceanogr. methodology 2:57-76.  Cody,  M.L. 1966. 174-184.  A  g e n e r a l  theory  of  c l u t c h  C o l e ,  L.C. 1954. phenomena.  The p o p u l a t i o n c o n s e q u e n c e s o f Q u a r t . Rev. B i o l . 29:103-137.  samplers.  s i z e .  UNESCO  E v o l u t i o n  l i f e  h i s t o r y  20:  175  Comita, G.W. 1968. Oxygen consumption Oceanogr. 13:51-57.  C o r k e t t ,  C . J .  and  I.A.  Pseudocalanus.  C u l v e r , D. f i r s t and E K e r f o Hamps  McLaren. Adv.  mar.  1978. B i o l .  i n  The  Diaptomus.  b i o l o g y  L i m n o l .  of  15:1-231.  1980. Seasonal v a r i a t i o n i n r e p r o d u c t i o n i n C l a d o c e r a , cology of Zooplankton Commun o t . U n i v e r s i t y P r e s s o f New hire  th p it En  e s i z e s at b i r t h 3 5 8 - 3 6 6 _in E v o l u i e s , e d i t e d by gland, Hanover,  and t i o n W.C. New  at  Cuzin-Roudy, J . , J . B e r r e u r - B o n n e n f a n t , and M.C. F r i e d M o n t a u f i e r . 1981. Chronology of post-embryonic development in S i r i e l l a armata (M. Edw.) ( C r u s t a c e a : Mysidacea) r e a r e d in the l a b o r a t o r y : growth and sexual d i f f e r e n t i a t i o n . I n t . J . I n v e r t e b r a t e R e p r o d u c t i o n 4:193-208.  Dagg,  M.J. 1976. Complete carbon and n i t r o g e n budgets f o r the c a r n i v o r o u s amphipod C a l l i o p i u s l a e v i u s c u l u s ( K r o y e r ) . Int. Revue ges. H y d r o b i o l . 61:297-357.  D e e v e y , G.B. 1960. R e l a t i v e e f f e c t s of temperature and food on seasonal v a r i a t i o n i n l e n g t h of marine copepods i n some e a s t e r n American and western European w a t e r s . B u l l . Bingham Oceanogr. C o l l . 17:54-85.  de  M a r c h , B.G.E. 1978. The e f f e c t s of c o n s t a n t and v a r i a b l e temperature on the s i z e , growth, and r e p r o d u c t i o n of the f r e s h w a t e r amphipod H y a l e l l a a z t e c a ( S a u s s u r e ) . Can. J . Z o o l . 56:1801-1806.  Dixon,  A.F.G. and P.W. r e p r o d u c t i o n i n 5:83-89.  W e l l i n g s . 1982. S e a s o n a l i t y a p h i d s . I n t . J . I n v e r t e b r a t e  D o r m a a r , K.A. and S. C o r e y . 1973. Some a s p e c t s o f in M y s i s s t e n o l e p i s ( C r u s t a c e a , M y s i d a c e a ) . Bd. Can. 30:1747-1749.  Doyle,  R.W.  and  W.  Hunte.  1981a.  Demography  of  an  and Reproduction  osmoregulation J . F i s h . Res.  e s t u a r i n e  amphipod Gammarus l a w r e n c i a n u s e x p e r i m e n t a l l y s e l e c t e d f o r h i g h " r " : a model of the g e n e t i c e f f e c t s of environmental change. Can. J . F i s h . Aquat. S c i . 38:1120-1127.  176  Doyle,  R.W. a n d W. and y i e l d of environment.  Hunte. 1981b. Genetic changes i n " f i t n e s s " a c r u s t a c e a n p o p u l a t i o n i n a c o n t r o l l e d J . exp. mar. B i o l . e c o l . 52:147-156.  D u n c a n , A. and R.Z. K l e k o w s k i . 1975. P a r a m e t e r s of an energy b u d g e t , p . 9 7 - 1 4 7 j_n M e t h o d s f o r E c o l o g i c a l Bioenerget i c s , e d i t e d b y W. G r o d z i n s k i , R.Z. K l e k o w s k i , and A. Duncan. B l a c k w e l l S c i e n t i f i c P u b l i c a t i o n s , O x f o r d .  D u r b i n , E.G., A.G. D u r b i n , T . J . Smayda, and P.G. V e r i t y . 1983. Food l i m i t a t i o n o f p r o d u c t i o n by a d u l t A c a r t i a tonsa i n N a r r a g a n s e t t Bay, Rhode I s l a n d . L i m n o l . Oceanogr. 28:11991213. .  E d m o n d s o n , W.T. 1974. V e r e i n . L i m n o l .  Secondary p r o d u c t i o n . 20:229-272.  M i t t .  I n t e r n a t .  E l l i o t t , J.M. 1 9 7 7 . Some m e t h o d s f o r the s t a t i s t i c a l a n a l y s i s samples of b e n t h i c i n v e r t e b r a t e s . S c i . P u b l . Freshwater B i o l . Assoc. 25:1-160.  E l l i o t t , J.M. and consumption 195-201.  W. D a v i s o n . 1975. Energy e q u i v a l e n t s of i n animal e n e r g e t i c s . O e c o l o g i a ( B e r l . )  of  oxygen 19:  E l m o r e , J . L . 1982. The i n f l u e n c e of food c o n c e n t r a t i o n and c o n t a i n e r volume on l i f e h i s t o r y parameters of Diaptomus d o r s a l i s March from s u b t r o p i c a l F l o r i d a . H y d r o b i o l o g i a 89: 215-223.  Evans,  F.  1981.  An  i n v e s t i g a t i o n  i n t o  the  r e l a t i o n s h i p  of  sea  temperature and food supply t o the s i z e of the p l a n k t o n i c copepod Temora l o n g i c o r n i s M u l l e r i n t h e North Sea. E s t u a r i n e , C o a s t a l and S h e l f Science 13:145-158.  Fager,  E.W. and R . I . C l u t t e r . 1968. Parameters of a n a t u r a l p o p u l a t i o n of a h y p o p e l a g i c marine mysid, Metamysidopsis e l o n q a t a (Holmes). P h y s i o l . Z o o l . 41:257-267.  F e i f a r e k , B.P., G.A. Wyngaard, and r e p r o d u c t i o n i n a f r e s h w a t e r 56:166-168.  J.D. A l l a n . 1983. The c o s t copepod. O e c o l o g i a ( B e r l . )  of  1 77  F i s h e r , R.A. 1930. The g e n e t i c a l theory of n a t u r a l s e l e c t i o n . (2nd e d i t i o n , 1 9 5 8 ) . D o v e r P u b l i c a t i o n s , New York  F o u l d s ,  J.B.  and  J.C.  R o f f .  1976.  Oxygen  consumption  s i m u l a t e d v e r t i c a l m i g r a t i o n i n Mysi s Mysidacea). Can. J . Z o o l . 54:377-385.  r e l i c t a  d u r i n g ( C r u s t a c e a ,  F u r s t ,  M. 1972. L i f e c y c l e , g r o w t h , and r e p r o d u c t i o n in Mysis r e l i c t a Loven. I n f o r m a t i o n f r a n S o t v a t t e n s - L a b o r a t o r i e t Drottningholm 11:1-41.  F u r s t ,  M. and r e l i c t a  L. Nyman. 1969. Isoenzyme polymorphism i n Mysis Loven. Rept. I n s t . Freshwater Res. Drottningholm  49:44-48.  Futuyma, D.J. 1979. E v o l u t i o n a r y I n c . S u n d e r l a n d , Mass.  Gaudy,  R. mysi Lept J . e  Gaudy,  R., J.P. comparee ( c a v e r n i c c a v e r n i c o B i o l . e c o  B i o l o g y .  Sinauer  A s s o c i a t e s ,  and J.P. G u e r i n . 1979. E c o p h y s i o l o g i e comparee des daces Hemimysis s p e l u n c o l a Ledoyer ( c a v e r n i c o l e ) et omysis 1ingvura G.O. Sars (non c a v e r n i c o l e ) . xp. mar. B i o l . e c o l . 38:101-119.  G u des o l e l e ) l .  e r i n , and M. Pagano. 1980. E c o p h y s i o l o g i e mysidaces Hemimysis s p e l u n c o l a Ledoyer ) et Leptomysis 1ingvura G.O. Sars (non : r e s p i r a t i o n et e x c r e t i o n . J . exp. mar. 44:29-46.  G i e s e l , J.T. 1976. Reproductive s t r a t e g i e s as a d a p t a t i o n s l i f e i n t e m p o r a l l y h e t e r o g e n e o u s e n v i r o n m e n t s . Ann. E c o l . S y s t . 7:57-79.  Gould,  Green,  to Rev.  S . J . and R.C. L e w o n t i n . 1979. The spandrels of San Marco and the P a n g l o s s i a n paradigm: a c r i t i q u e of the a d a p t i o n i s t programme. P r o c . R. Soc. Lond. B 205:581-598.  J .  1956.  Growth,  (Crustacea: 204.  s i z e ,  C l a d o c e r a ) .  and  r e p r o d u c t i o n  Proc.  Z o o l .  Soc.  i n  Daphnia  Lond.  126:173-  1.78  Green,  J .  1966.  C l a d o c e r a .  Seasonal J .  v a r i a t i o n  Anim.  E c o l .  i n  egg  p r o d u c t i o n  by  35:77-104,  G r i f f i t h s , D. 1977. C a l o r i c v a r i a t i o n i n C r u s t a c e a a n i m a l s . J . Anim. E c o l . 46:593-605.  and  other  Gupta,  A.P. and R.C. L e w o n t i n . 1982. A study of r e a c t i o n in n a t u r a l p o p u l a t i o n s of D r o s o p h i l a pseudobscura• E v o l u t i o n 36:934-948.  H a i r ,  J.R. 1971. Upper l e t h a l tempe t o l e r a n c e s of the opossum shr from the Sacramento-San J o a q u C a l i f . F i s h and Game 5 7 : 1 7 - 2 7  norms  r a t u r e and thermal shock imp Neomysis a w a t s c h e n s i s i n e s t u a r y , C a l i f o r n i a . .  H a k a l a , I. 1979. Seasonal v a r i a t i o n i n the carbon and energy c o n t e n t s and a s s i m i l a t i o n of a Mysis r e l i c t a p o p u l a t i o n i n P a a j a r v i , s o u t h e r n F i n l a n d . Ann. Zool.. F e n n i c i 16:129-137.  H a r g r a v e , B.T. 1971. An amphipod. L i m n o l .  H a r g r a v e , B.T. and z o o p l a n k t o n .  energy budget f o r a d e p o s i t - f e e d i n g Oceanogr. 16:99-103.  G.H. Geen. 1968. Phosphorus e x c r e t i o n L i m n o l . Oceanogr. 13:332-342.  H a r r i s o n , B.J. 1981. The b i s t r u c t u r e of h a r p a c t i e s t u a r i n e i n t e r t i d a l Ph.D. T h e s i s , U n i v e r s  H a r t ,  o l c o f l i t  o g i i d a t y o  c a l d copep (Fras f B r i  e o e t  by  t e r m i n a n t s of the d communities on an r R i v e r d e l t a , B.C.). i s h Columbia, Vancouver.  R.C. and I.A. McLaren. 1978. Temperature a c c l i m a t i o n and other i n f l u e n c e s on e m b r y o n i c d u r a t i o n i n the copepod Pseudocalanus sp. Marine B i o l o g y 45:23-30.  H a r t n o l l , R.G. 1982. G r o w t h , p . 11 1 - 1 9 6 i_n T h e B i o l o g y of C r u s t a c e a . V o l . 2, e d i t e d by L.G. A b e l e . Academic P r e s s , New York.  Herman, S.S. 1963. V e r t i c a l m i g r a t i o n of the opossum shrimp Neomysis americana Smith. L i m n o l . Oceanogr. 8:228-238.  1 79  H e u b a c h , W.. 1969. Neomysis a w a t s c h e n s i s i n the Joaquin R i v e r e s t u a r y . L i m n o l . Oceanogr.  Sacramento-San 14:533-546.  H i r s h f i e l d , M.F. 1980. An e x p e r i m e n t a l a n a l y s i s of r e p r o d u c t i v e e f f o r t and c o s t i n the Japanese medaka, O r y z i a s l a t i p e s . Ecology 6J_:282-292.  H i r s h f i e l d , M.F. and D.W. T i n k l e . 1975. N a t u r a l s e l e c t i o n and the e v o l u t i o n of r e p r o d u c t i v e e f f o r t . P r o c . Nat. Acad. S c i . USA 72:2227-2231.  Hodgins, D.O. 1974. S a l i n i t y B r i t i s h Columbia. Ph.D. Columbia, Vancouver.  Holmes,  S . J .  1897.  Merced.  i n t r u s i o n s i n the F r a s e r R i v e r , T h e s i s , U n i v e r s i t y of B r i t i s h  D e s c r i p t i o n  P r o c .  C a l i f .  of  Acad.  a  new  s c h i z o p o d  S c i . 2nd  H o l m q u i s t , C. 1973. Taxonomy, d i s t r i b u t i three s p e c i e s Neomysis i n t e r m e d i a a w a t s c h e n s i s (Brandt) and N. merce M y s i d a c e a ) . Z o o l . J b . S y s t . Bd. 1  Horn,  H.S. 1978. Op h i s t o r y , p.41 approach, e d i S c i e n t i f i c P u  G.E.  1967.  I n t r o d u c t i o n to Wiley and Sons,  Hynes,  I i ,  N.  from  Lake  6:199-200.  o n , and ecology of the ( C z e r n i a v s k y ) , N. dis Holmes ( C r u s t a c e a , 00:197-222.  timal t a c t i c s of r e p r o d u c t i o n and l i f e 1-429 _in B e h a v i o r a l E c o l o g y : an e v o l u t i o n a r y t e d by J . R . Krebs and N.B. D a v i e s . B l a c k w e l l b l . , O x f o r d .  H u t c h i n s o n , G.E. 1951. Copepodology Ecology 32:571-577.  H u t c h i n s o n ,  s e r i e s  A  T r e a t i s e  Lake New  B i o l o g y York.  f o r  on  the  o r n i t h o l o g i s t .  Limnology.  and  the  V o l .  2.  Limnoplankton.  John  H.B.N. 1954. The ecology of Gammarus d u e b e n i L i l l j e b o r g and i t s occurrence i n f r e s h water i n western B r i t a i n . J . Anim. E c o l . 23:38-84.  1964.  Mysidacea.  Fauna  J a p o n i c a ,  Tokyo.  180  Jawed,  M. 1969. Body n i t r o g e n and n i t r o g e n o u s e x c r e t i o n . i n N e o m y s i s r a y i i M u r d o c h a n d E u p h a u s i a p a c if i c a H a n s e n . L i m n o l . Oceanogr. 14 : 7 4 8 - 7 5 4 .  Jawed,  M. 1973. E f f e c t s of e n v i r o n m e n t a l f a c t o r s and body s i z e on r a t e s of oxygen consumption i n Archaeomysis q r e b n i t z k ii and Neomysis awatschensis ( C r u s t a c e a : Mysidae). Marine B i o l o g y 2J_: 1 7 3 - 1 7 9 .  Johns,  D.M., W . J . B e r r y , a n d W. W a l t o n . and r e p r o d u c t i v e p o t e n t i a l of t h e Molenock f e d v a r i o u s g e o g r a p h i c a l shrimp, A r t e m i a . J . e x p . mar. B i o l  1981. mysid s t r a i n . e c o l  S u r v i v a l , growth, M y s i d b p s i s bahia s o f t h e b r i n e . 53:209-219.  Johnson, J . T . and T.L.Hopkins. 1978. Biochemical c o m p o s i t i o n the mysid shrimp Taphromysis bowmani Bacescu. J . e x p . B i o l . e c o l . 31:1-9.  Johnston,  N.T.  and  D.C.  Lasenby.  1982. D i e t  and  f e e d i n g  of mar.  of  Neomysis mercedis Holmes ( C r u s t a c e a , Mysidacea) from t h e F r a s e r R i v e r e s t u a r y , B r i t i s h C o l u m b i a . Can. J . Z o o l . 60: 813-824.  Kalmer, E. 1969. A comparison of t h e c l o s e d - b o t t l e and f l o w i n g water methods f o r measurement of r e s p i r a t i o n i n a q u a t i c i n v e r t e b r a t e s . P o l . A r c h . H y d r o b i o l . 16:31-49.  Kaplan, R.H. 1980. The i m p l i c a t i o n s o f ovum s i z e v a r i a b i l i t y f o r o f f s p r i n g f i t n e s s and c l u t c h s i z e w i t h i n s e v e r a l p o p u l a t i o n s of salamanders (Ambystoma). E v o l u t i o n 34:51-  Kaplan, R . H . a n d W.S. Cooper. 1984. The e v o l u t i o n of developmental p l a s t i c i t y i n r e p r o d u c t i v e c h a r a c t e r i s t i c s : an a p p l i c a t i o n of t h e " a d a p t i v e c o i n - f l i p p i n g " p r i n c i p l e . Am. N a t . 1 2 3 : 3 9 3 - 4 1 0 .  K e r f o o t , W.C. 1974. Egg-size 1259-1270.  Kinne, -  c y c l e  of  a  c l a d o c e r a n .  0 . 1955. Neomysis v u l g a r i s Thompson, b i o l o g i s c h e s t u d i e . B i o l Z e n t r a l b l .  Ecology  55:  eine a u t o k o l o g i s c h e 74:160-202.  181  Kinne,  0. 1970. T e m p e r a t u r e - i n v e r t e b r a t e s , E c o l o g y . Vol.1 , p a r t 1, e d i t e d b y O. S o n s , New York  K i n n e ,  0. 1971. S a l i n i t y - i n v e r t e b r a t e s , p.821-995 in Marine E c o l o g y . V o l . 1, p a r t 2 , e d i t e d b y 0 . K i n n e . J o h n s Wiley and S o n s , New York  K i s t r i t z , R.U. and f l u x , and n u t e s t u a r y . West Columbia, Tec  K l e i n  p . 4 0 7 - 5 1 4 _in. M a r i n e K i n n e . John Wiley and  I. Y e s a k i . 1979. Primary p r o d u c t i o n , d e t r i t u s r i e n t c y c l i n g i n a sedge marsh, F r a s e r R i v e r water Research C e n t r e , U n i v e r s i t y of B r i t i s h h . R e p t . No. 17:1-53.  B r e t e l e r , W.C.M. a n d S.R. G o n z a l e z . 1982. I n f l u e n c e of c u l t i v a t i o n and f o o d c o n c e n t r a t i o n on body l e n g t h of c a l a n o i d copepods. Marine B i o l o g y 71:157-161.  Knutson j r . , A.C. and J . J . O r s i . 1983. F a c t o r s r e g u l a t i n g abundance and d i s t r i b u t i o n of the shrimp Neomysis mercedis in the Sacramento-San J o a q u i n e s t u a r y . Trans. Amer. F i s h . Soc. 112:476-485.  K o s t ,  A,L.B. and A.W. mercedis Holmes C a l i f . F i s h and  K n i g h t . 1975. The food of Neomysis i n the Sacramento-San Joaquin e s t u a r y . Game 61:35-46.  K u z ' m i c h e v a , V . I . and I.V. K u k i n a . 1974. I n t e n s i t y of r e s p i r a t i o n of m y s i d s when p a c k e d i n r e s p i r o m e t e r s d i f f e r e n t i n t e n s i t i e s . Oceanology 14:732-736.  L a m p e r t , W. 1978. A f i e l d study on the f e c u n d i t y of Daphnia s p . on food ( B e r l . ) 36:362-369.  dependence  of  c o n c e n t r a t i o n .  at  the O e c o l o g i a  L a s e n b y , D.C. 1971. The ecology of M y s i s r e l i c t a i n an a r c t i c and a temperate l a k e . Ph.D. T h e s i s , U n i v e r s i t y of Toronto, O n t a r i o  L a s e n b y , D.C. and R.R. L a n g f o r d . 1972. Growth, l i f e r e s p i r a t i o n of M y s i s r e l i c t a i n an a r c t i c and l a k e . J . F i s h . Res. Bd. Can. 29:1701-1708.  h i s t o r y , and temperate  1 82  L a s k e r , R. Feeding, g r o w t h , r e s p i r a t i o n , and carbon of a e u p h a u s i i d c r u s t a c e a n . J . F i s h . Res. Bd. 1291-1317.  u t i l i z a t i o n Can. 23:  L a w l o r , L.R. 1976. P a r e n t a l investment and o f f s p r i n g f i t n e s s the t e r r e s t i a l isopod A r m a d i l l i d i u m v u l g a r e ( L a t r . ) ( C r u s t a c e a , O n i s c o i d e a ) . E v o l u t i o n 30:775-785.  L e v i n s , R. 1968. U n i v e r s i t y  E v o l u t i o n i n Changing E n v i r o n m e n t s . P r e s s , P r i n c e t o n , N.J.  L e v i n t o n , J.S. 1980. Genetic divergence in E s t u a r i n e P e r s p e c t i v e s , e d i t e d A c a d e m i c P r e s s , New York.  r e u i  t h c o t n i l e a r y . t i s h  e . sal Wes C o l  i n by  i n  P r i n c e t o n  e s t u a r i e s , p.509-520 V.S. Kennedy.  Levy,  D.A. and T.G. N o abundance of j u v Fraser R i v e r e s t U n i v e r s i t y of B r  1981. The d i s t r i mon i n marsh h a b twater Research u m b i a , Tech. Rep  b u t i o n and i t a t s of the C e n t r e , t . No. 25:1-117.  Levy,  D.A. and T.G. N o r t h c o t e . 1982. J u v e n i l e salmon r e s i d e n c y in a marsh area of the F r a s e r R i v e r e s t u a r y . Can. J . F i s h . Aquat. S c i . 39:270-276.  Levy,  D.A., T.G. N o r t h c o t e , and G.J. B i r c h . 1979. J u v e n i l e salmon u t i l i z a t i o n of t i d a l channels i n the Fraser R i v e r e s t u a r y , B r i t i s h Columbia. Westwater Research Centre, U n i v e r s i t y of B r i t i s h C o l u m b i a , T e c h . R e p t . No. 23:1-70.  Lewontin, R.C. 1965. S e l e c t i o n f o r c o l o n i z i n g a b i l i t y , p. 79-94 i n The G e n e t i c s o f C o l o n i z i n g S p e c i e s , e d i t e d by H.G. Baker and G.L. S t e b b i n s . Academic P r e s s , New York.  L i n f o r d , E. 1965. Biochemical s t u d i e s on m a r i n e z o o p l a n k t o n . V a r i a t i o n i n the l i p i d content of some M y s i d a c e a . J . C o n s . i n t . E x p l o r . Mer 30:16-27.  I I .  L o c k w o o d , A.P.M. 1976. P h y s i o l o g i c a l a d a p t a t i o n to l i f e i n e s t u a r i e s , p . 3 1 5 - 3 9 2 i_n A d a p t a t i o n to Environment, e d i t e d by R.C. N e w e l l . B u t t e r w o r t h s , London  183  Lynch,  M. 1 9 8 2 . How w e l l does the Edmondson-Paloheimo approximate instantaneous b i r t h r a t e s ? Ecology  Lynch,  M. 1983. E s t i m a t i o n of zooplankton p o p u l a t i o n s Oceanogr. 28:533-545.  Mark,  G.A.  1982.  An  s i z e - s p e c i f i c m o r t a l i t y r a t e s by p e r i o d i c s a m p l i n g . L i m n o l .  e x p e r i m e n t a l  study  of  e v o l u t i o n  heterogeneous environments: p h e n o l o g i c a l b r u c h i d b e e t l e . E v o l u t i o n 36:984-997.  M a s h i k o , K. 1982. c l u t c h s i z e Haan i n t h e  model 63:12-18.  i n  i n  a d a p t a t i o n  by  D i f f e r e n c e s i n both the egg s i z e and t h e of the freshwater prawn Palaemon p a u c i d e n s Sagami R i v e r . J a p . J . E c o l . 32:445-451.  a  de  M a t s u d a i r a , C., T. K a r i y a , a n d T . T s u d a . 1952. The s t u d y on the b i o l o g y of a mysid G a s t r o s a c c u s v u l g a r i s Nakazawa. Tohoku J . A g r i c . Res. 3:155-174.  M a u c h l i n e , J . 1 9 7 1 . The b i o l o g y M y s i d a c e a ) . J . mar. b i o l .  of Neomysis i n t e g e r ( C r u s t a c e a , A s s . U.K. 51 : 3 4 7 - 3 5 4 .  M a u c h l i n e , J . 1973a. The broods of B r i t i s h ( C r u s t a c e a ) . J . mar. b i o l . A s s . U.K.  Mysidacea 53:801-817.  M a u c h l i n e , J . 1973b. Inter-moult ( C r u s t a c e a ) . J . mar. b i o l .  s p e c i e s of Mysidacea 53:569-572.  growth of A s s . U.K.  M a u c h l i n e , J . 1977. Growth and m o l t i n g of C r u s t a c e a , e s p e c i a l l y e u p h a u s i i d s , p.401-422 i_n O c e a n Sound S c a t t e r i n g P r e d i c t i o n , e d i t e d b y N.R. Anderson and B . J . Z a h u r a n e c . P l e n u m P r e s s , New York  M a u c h l i n e , 369.  Mayr,  E. Nat.  J .  1983.  1980.  How  121:324.  The  t o  b i o l o g y  c a r r y  out  of  the  m y s i d s .  Adv.  a d a p t i o n i s t  Mar.  B i o l  program?  18:1-  Am.  1 84  M a c A r t h u r , R.H. and Biogeography.  E.O. W i l s o n . 1967. The Theory of I s l a n d P r i n c e t o n U n i v e r s i t y P r e s s , P r i n c e t o n , N.J.  M c L a r e n , I.A. 1963. E f f e c t s o f t e m p e r a t u r e on g r o w t h of z o p p l a n k t o n , and the a d a p t i v e value of v e r t i c a l m i g r a t i o n . J . F i s h . Res. Bd. Can. 20:685.  M c L a r e n , I.A. 1965. Some r e l a t i o n s h i p s between t e m p e r a t u r e and egg s i z e , body s i z e , development r a t e , and f e c u n d i t y of the copepod P s e u d o c a l a n u s . L i m n o l .Oceanogr. 10:5 2 8 - 5 3 8 .  M c L a r e n , I.A. 1976. I n h e r i t a n c e of demographic and p r o d u c t i o n parameters i n the marine copepod Eurytemora herdmani. B i o l . B u l l . 151:200-213.  M e y e r s , D.G. 1984. Egg development of a c h y d o r i d c l a d o c e r a n , Chydorus s p h a e r i c u s , exposed t o c o n s t a n t and a l t e r n a t i n g temperatures: s i g n i f i c a n c e t o secondary p r o d u c t i v i t y i n f r e s h w a t e r s . E c o l o g y 65:309-320.  Morgan, M.D. 1980. L i f e h i s t o r y i n t r o d u c e d p o p u l a t i o n s of 561 .  M u r a n o , M. 1964. F i s h e r i e s Neomysis i n t e r m e d i a C s p e c i a l r e f e r e n c e t o A q u a c u l t u r e (Japan)  c h a r a c t e r i s t i c s of two M y s i s r e l i c t a . E c o l o g y  61 : 5 5 1  -  b i o l o g y of a marine r e l i c t mysid z e r n i a w s k y . I I I .L i f e c y c l e , w i t h the r e p r o d u c t i o n of the m y s i d . 12:19-30.  M u r t a u g h , P.A. 1983. M y s i d l i f e h i s t o r y and in p r e d a t i o n p r e s s u r e on z o o p l a n k t o n . S c i . 40:1968-1974.  s e a s o n a l v a r i a t i o n Can. J . F i s h . Aquat.  N a i r ,  K.B. 1939. The r e p r o d u c t i o n , o o g e n e s i s , and development of Mesopodopsis o r i e n t a l i s T a t t . P r o c . I n d i a n A c a d . S c i . B9: 195-229.  N e i l l ,  W.E. 1981a. Developmental responses of j u v e n i l e Daphnia rosea t o e x p e r i m e n t a l a l t e r a t i o n of t e m p e r a t u r e and n a t u r a l seston c o n c e n t r a t i o n . Can. J . F i s h . Aquat. S c i . 38:1357-1362.  185  N e i l l ,  W.E. 1981b. Impact of Chaoborus p r e d a t i o n upon the s t r u c t u r e and dynamics of a c r u s t a c e a n zooplankton community. Oecologia ( B e r l . ) 48:164-177.  N e l s o n , W.G. 1980. Reproductive p a t t e r n s amphipods. S a r s i a 65:61-71 .  N o r t h c o t e , T.G. 1974. B i o l o g y of Westwater Research C e n t r e , T e c h . R e p t . No. 3:1-94.  of  gammaridean  the lower F r a s e r R i v e r . U n i v e r s i t y of B r i t i s h Columbia,  N o r t h c o t e , T.G. and R. C l a r o t t o . 1975. L i m n e t i c macrozooplankton and f i s h p r e d a t i o n i n some c o a s t a l B r i t i s h Columbia l a k e s . Verh. I n t e r n a t . V e r e i n . L i m n o l . 19:2378-2393.  N o r t h c o t e , T.G., G.L. E and p l a n k t o n i c al to water q u a l i t y U n i v e r s i t y of B r i  n n i s , and M.H. Anderson. gae of the lower F r a s e r R c o n d i t i o n s . Westwater Res t i s h Columbia, Tech. Rept  1975. P e i v e r i n earch Ce . No. 8:  r i p h y t i c r e l a t i o n ntre, 1-61.  N o r t h c o t e , T.G., N.T. Johnston, and K. Tsumura. 1976. B e n t h i c , e p i b e n t h i c , and d r i f t fauna of the lower F r a s e r R i v e r . Westwater Research C e n t r e , U n i v e r s i t y of B r i t i s h Columbia, T e c h . R e p t . No. jj_: 1-227.  N o r t h c o t e , T.G., N.T. Johnston, and K. Tsumura. 1978. A r e g i o n a l c o m p a r i s o n of s p e c i e s d i s t r i b u t i o n , abundance, s i z e , and other c h a r a c t e r i s t i c s of lower Fraser R i v e r f i s h e s . Westwater Research C e n t r e , U n i v e r s i t y of B r i t i s h Columbia, T e c h . R e p t . No. _1_4 : 1 -38 .  Paloheimo, J . L i m n o l .  1974. C a l c u l a t i o n of instantaneous Oceanogr. 19:692-694 .  P a r k e r , M. and B. W e s t . 1979. The n a t u r a l h i s t o r y i n t e g e r (Leach) i n Lough Furnace, Co. Mayo, lough i n the west of I r e l a n d . E s t u a r i n e and Science 8:157-167.  b i r t h  r a t e .  of Neomysis a b r a c k i s h C o a s t a l Marine  P a r k i n s o n , E.A. 1981. Genetic s t r u c t u r e i n p o p u l a t i o n s of s t e e l h e a d t r o u t i n B r i t i s h C o l u m b i a . M.Sc. T h e s i s , U n i v e r s i t y of B r i t i s h Columbia, Vancouver.  186  Pezzack, D.S. and S. C o r e y . 1979. The l i f e h i s t o r y and d i s t r i b u t i o n of Neomysis americana (Smith) ( C r u s t a c e a , Mysidacea) i n Passamaquoddy Bay. Can. J . Z o o l . 57:785-793.  P i a n k a , E.R. and W.S. P a r k e r . 1975. A g e - s p e c i f i c t a c t i c s . Am. Nat. 109:453-464.  r e p r o d u c t i v e  Raymont, J.E.G. and S. K r i s h n a s w a m y . 1968. A method for d e t e r m i n i n g the oxygen output and carbon d i o x i d e output i n Neomysis i n t e g e r . I n t . Revue ges. H y d r o b i o l . 53:563-572.  Raymont, J.E.G., J . A u s t i n , and E. L i n f o r d . 1964. B i o c h e m i c a l s t u d i e s on m a r i n e z o o p l a n k t o n . I. The b i o c h e m i c a l c o m p o s i t i o n of Neomysis i n t e g e r . J . Cons. i n t . E x p l o r . Mer 28:354-363.  Raymont, J.E.G., J . A u s t i n , and E. L i n f o r d . 1966. s t u d i e s on m a r i n e z o o p l a n k t o n . I I I . Seasona the b i o c h e m i c a l c o m p o s i t i o n of Neomysis i n t in Some C o n t e m p o r a r y S t u d i e s i n M a r i n e S c i e H. Barnes.  Raymont, J.E.G., s t u d i e s on major b i o c h J. mar. b i o  Reynolds, J.B. c h a r a c t e r s o u t h e a s t Great Lak  J m e l  . ar m i .  A i c A  u n a s  s t i n , and E. L i n f o r d . 1968. B i o c h e m i c a l e z o o p l a n k t o n . V. The composition of the l f r a c t i o n s i n Neomysis i n t e g e r . s . U.K. 48:735-760.  and G.M. DeGraeve. 1972. Seasonal p o p u l a t i o n i s t i c s of the opossum shrimp Mysis r e l i c t a i n e r n Lake M i c h i g a n , 1970-71. P r o c . 15th Conf. es Res.,1972. 117-131  R e z n i c k , D. 1983. The s t r u c t u r e of t r a d e o f f s between g r o w t h and 873.  Richman,  S.  E c o l .  R i c k l e f s ,  1958.  The  Monogr.  R.E.  B i o c h e m i c a l l v a r i a t i o n i n e g e r , p.597-605 n c e , e d i t e d by  1973.  guppy l i f e h i s t o r i e s : r e p r o d u c t i o n . Ecology  t r a n s f o r m a t i o n  of  energy  by  Daphnia  the 64:862-  p u l e x .  28:273-291.  E c o l o g y .  C h i r o n  P r e s s ,  P o r t l a n d ,  Oregon.  187  Sandeman, ambi and M y s i  I .M. a n d D.C. L a s e n b y . 1980. The r e l a t i o n s h i p between ent oxygen c o n c e n t r a t i o n , t e m p e r a t u r e , body weight, oxygen consumption f o r Mysis r e l i c t a ( M a l a c o s t r a c a : d a c e a ) . Can. J . Zool. 58:1032-1036.  S c h a f f e r ,  W.M.  e f f e c t s  1974. of  age  S c h i n d l e r , D.W., A. c a l o r i c v a l u e with a P h i l l i samples. J . F  S e i t z ,  S e l e c t i o n s t r u c t u r e .  f o r o p t i m a l Ecology  S. C l a r k , and s of freshwate p s o n bomb c a l o i s h . Res. Bd.  l i f e  h i s t o r i e s :  the  55:291-303.  J.R. G r a y . 1971. Seasonal r z o o p l a n k t o n , as determined r i m e t e r m o d i f i e d f o r small Can. 28:559-564.  A. 1 9 7 9 . On the c a l c u l a t i o n of b i r t h r a t e s and death r a t e s i n f l u c t u a t i n g p o p u l a t i o n s w i t h c o n t i n u o u s r e c r u i t m e n t . O e c o l o g i a ( B e r l . ) 41:343-360.  S h e a d e r , M. 1983. The r e p r o d u c t i v e b i o l o g y and ecology of Gammarus d u e b e n i (Crustacea: Amphipoda) i n southern England. J . mar. b i o l . A s s . U.K. 63:517-540.  S h u s h k i n a , E.A. 1972. I n t e n s i t y of p r o d u c t i o n and u t i l i z a t i o n a s s i m i l a t e d food f o r growth of mysids from the sea of Japan. Oceanology 12:275-285.  of  S h u s h k i n a , E.A., V . I . K u z ' m i c h e v a , and L.A. O s t a p e n k o . 1971. Energy e q u i v a l e n t of body mass, r e s p i r a t i o n , and c a l o r i c value of m y s i d s from the Sea of Japan. Oceanology 11:880889.  S i e g f r i e d , C.A. 1982. T r o p h i c r e l a t i o n s of Crangon franc i scorum Stimpson and Palaemon m a c r o d a c t y l u s Rathbun: p r e d a t i o n on the opossum shrimp, Neomysis mercedis Holmes. H y d r o b i o l o g i a 89:129-139.  S i e g f r i e d , C.A. a n d M.E. mercedis (Holmes).  Kopache. 1980. Feeding of B i o l . B u l l . 159:193-205.  S i e g f r i e d , C.A., M.E. K o p a c h e , a n d A.W. K d i s t r i b u t i o n and abundance of Neomy r e l a t i o n t o the entrapment zone i n San J o a q u i n d e l t a . T r a n s . Amer. F i s  n i g h sis the h . S  Neomysis  t . 1979. The mercedis i n western Sacramentooc. 108:262-270.  188  S i m m o n s , M.A. a n d A.W. K n i g h t . 1975. R e s p i r a t o r y response of Neomysis intermedia ( C r u s t a c e a , Mysidacea) t o changes i n s a l i n i t y , t e m p e r a t u r e , a n d s e a s o n . Comp. B i o c h e m . P h y s i o l . 50A:181-193.  Smith,  C C . a n d S.D. F r e t w e l l . 1974. The optimal balance between s i z e a n d n u m b e r o f o f f s p r i n g . Am. N a t . 1 0 8 : 4 9 9 - 5 0 6 .  Smyly,  W.J.P. 1973. C l u t c h - s i z e copepod, Cyclops strenuus t h o r a c i c volume and food.  S n e l l ,  T.W. and C E . K i n g . 1977. L i f e s p a n and f e c u n d i t y p a t t e r n s in r o t i f e r s : t h e cost o f r e p r o d u c t i o n . E v o l u t i o n 31:882890.  i n t h e freshwater c y c l o p o i d abyssorum Sars i n r e l a t i o n t o J . n a t . H i s t . 7:545-549.  S t e a r n s , S . C 1976. L i f e - h i s t o r y Q u a r t . R e v . B i o l . 51:3-47.  t a c t i c s :  S t e a r n s , S.C. 1977. The e v o l u t i o n of l i f e c r i t i q u e of t h e theory and a review E c o l . S y s t . 8 : 145-171.  S t e a r n s , S.C. 1980. A 35:266-281.  new  view  of  l i f e  a  review  of  t h e  h i s t o r y t r a i t s : a o f t h e d a t a . Ann.  h i s t o r y  e v o l u t i o n .  S t e a r n s , S.C. 1983a. A n a t u r a l experiment i n l i f e - h i s t o r y e v o l u t i o n : f i e l d data on t h e i n t r o d u c t i o n o f t h e m o s q u i t o f i s h (Gambusia a f f i n i s ) t o H a w a i i . E v o l u t i o n 601-617.  S t e a r n s , S.C. h i s t o r y (Gambusi E v o l u t i o  i d e a s .  Rev.  Oikos  37:  1983b. The g e n e t i c b a s i s of d i f f e r e n c e s i n l i f e t r a i t s among s i x p o p u l a t i o n s o f m o s q u i t o f i s h a a f f i n i s ) t h a t shared a n c e s t o r s i n 1905. n 37:618-627.  S t e e l e , D.H. a n d V . J . S t e e l e . 1 9 7 5 a . T h e b i o l o g y o f Gammarus ( C r u s t a c e a , Amphipoda) i n t h e northwestern A t l a n t i c . X I . Comparison and d i s c u s s i o n . Can. J . Z o o l . 53:1116-1126.  189  S t e e l e , D.H. and V . J . S t e e l e . 1975b. Egg s i z e and d u r a t i o n embryonic development i n C r u s t a c e a . I n t . Revue ges. H y d r o b i o l . 60:711-715.  Stenson,  J.A.E.  1976.  c o m p o s i t i o n 2j_:8l4-822.  S t r o n g , an  D.R.  of  1972.  amphipod  S i g n i f i c a n c e Bosmina  L i f e  spp.  h i s t o r y  ( H y a l e l l a  of  predator  i n f l u e n c e  p o p u l a t i o n s .  v a r i a t i o n  a z t e c a ) .  L i m n o l .  among  Ecology  of  on Oceanogr.  p o p u l a t i o n s  of  53:1103-1111.  Takahashi, M., K . F u j i and T.R. Parsons. 1973. S i m u l a t i o n study of p h y t o p l a n k t o n p h o t o s y n t h e s i s and growth i n the F r a s e r R i v e r e s t u a r y . Marine B i o l o g y 19:102-116.  T a t t e r s a l l , W.M. Mysidacea.  and The  O.S. Ray  T a t t e r s a l l . 1951. S o c i e t y , London.  The  T a y l o r , B.E. and M. S l a t k i n . 1981. E s t i m a t i n g r a t e s of z o o p l a n k t o n . L i m n o l . Oceanogr.  B r i t i s h  b i r t h and death 26:143-158.  T a y l o r , H.M., R.S. G o u r l e y , C.E. L a w r e n c e , and R.S. Kaplan. 1974. N a t u r a l s e l e c t i o n of l i f e h i s t o r y a t t r i b u t e s : an a n a l y t i c a l approach. Theor. P o p u l . B i o l . 5:104-122.  T i n k l e , D.W. and N.F. Hadley. 1975. L i z a r d r e p r o d u c t i v e e f f o r t : c a l o r i c e s t i m a t e s and c o m m e n t s on i t s e v o l u t i o n . Ecology 56:427-434.  Toda,  H., M. Takahashi, and S. I c h i m u r a . 1981. Dynamics a n a l y s i s in p o p u l a t i o n change of Neomysis i n t e r m e d i a i n a hypere u t r o p h i c Lake K a s u m i g a u r a , J a p a n . A b s t r a c t s of the 44th Annual Meeting, ASLO, p.71  Toda,  H., M. Takahashi, and S. Ichimura. 1982. Abundance l i f e h i s t o r y of Neomysis i n t e r m e d i a Czerniawsky i n Kasumigaura. H y d r o b i o l o g i a 93:31-39.  Toda,  H., M. Takahashi, and S. Ichimura. 1983. Temperature c o n t r o l on the post-embryonic growth of Neomysis i n t e r m e d i a Czerniawsky i n a h y p e r e u t r o p h i c temperate J . P l a n k t o n Research 5:377-392.  and Lake  l a k e .  190  Toda,  H . , M. T a k a h a s h i , and S. I c h i m u r a . 1984. temperature on t h e post-embryonic growth i n t e r m e d i a Czerniawsky ( C r u s t a c e a , Mysida l a b o r a t o r y c o n d i t i o n s . J . P l a n k t o n Resear  The e f f e c t o f o f Neomysi s ceal under ch 6:647-662.  Tuomi,  J . ,T. H a k a l a , a n d E . H a u k i o j a . 1 9 8 3 . A l t e r n a t i v e concepts o f r e p r o d u c t i v e e f f o r t , c o s t s o f r e p r o d u c t i o n , and s e l e c t i o n i n l i f e - h i s t o r y e v o l u t i o n . Amer. Zool. 23: 25-34.  Turner, J . L . a n d D.W. K e l l e y . 1966. E c o l o g i c a l s t u d i e s of t h e Sacramento - San J o a q u i n . P a r t I I . F i s h e s o f t h e d e l t a . C a l i f . D e p t . F i s h a n d Game F i s h B u l l . 136:1-168.  T y l e r ,  Van  A.V. 1973. C a l o r i c v a l u e s o f i n v e r t e b r a t e s . Marine B i o l o g y  some N o r t h A t l a n t i c 19 : 2 5 8 - 2 6 1 .  Dolah, R.F. and E. B i r d . 1980. A comparison o f r e p r o d u c t i v e p a t t e r n s i n e p i f a u n a l and i n f a u n a l Gammaridean amphipods. E s t u a r i n e and C o a s t a l Marine S c i e n c e . 11:593-604.  V a n n u c c i , M. 1968. Loss Monogr. oceanogr.  o f organisms methodology  through meshes. 2:77-86.  UNESCO  V i d a l ,  J . 1980a. P h y s i o e c o l o g y o f z o o p l a n k t o n . I. E f f e c t s o f p h y t o p l a n k t o n c o n c e n t r a t i o n , temperature, and body s i z e on the growth rate o f Calanus p a cifi c u s a n d P s e u d o c a l a n u s s p . Marine B i o l o g y 56:111-134.  V i d a l ,  J . 1980b. P h y s i o e c o l o g y o f z p h y t o p l a n k t o n c o n c e n t r a t i o n , the development and m o l t i n g r Pseudocalanus s p . Marine B i o l  V i d a l ,  J . 1980c. P h y s i o e c o l o g y o f z o o p l a n k t o n . I I I . E f f e c t s of p h y t o p l a n k t o n c o n c e n t r a t i o n , temperature, and body s i z e on the m e t a b o l i c rate o f Calanus p a cif i c u s . M a r i n e B i o l o g y 56:195-202..  o t a o  o p l a n k t o n . I I . E f f e c t s o f emperature, and body s i z e on t e s o f Calanus p a c i f i c u s and g y 56:135-146.  V i j v e r b e r g , J . 1976. The e f f e c t s o f food q u a n t i t y and q u a l i t y the growth, b i r t h - r a t e and l o n g e v i t y o f Daphnia h y a l i n a L e y d i g . H y d r o b i o l o g i a 51:99-108.  on  191  V l a s b l o m , oxy i n t in N e t  g e d h  A.G. and J.H.B. E l g e r s h u i z e n . 1977. S u r v i v a l and en consumption of Praunus f l e x u o s u s and Neomysis g e r and embryonic development of the l a t t e r s p e c i e s , i f f e r e n t temperature and c h l o r i n i t y c o m b i n a t i o n s . e r l a n d s J . Sea Res. 1 1: 3 0 5 - 3 1 5 .  V o r s t m a n , A.G. 1951. A year's i n v e s t i g a t i o n on the l i f e c y c l e Neomysis v u l g a r i s Thompson. Verh. I n t e r n a t . V e r e i n . L i m n o l . 1 1 :437-445.  W i g l e y , R.L. and B.R. Burns. 1971. D i s t r i b u t i o n and b i o l o g y mysids ( C r u s t a c e a , Mysidacea) from the A t l a n t i c coast t h e U n i t e d S t a t e s i n t h e NMFS Woods H o l e c o l l e c t i o n . F i s h e r y B u l l e t i n 69:717-746.  W i l l i a m s , A.B. C a r o l i n a 254-262.  W i l l i a m s D i th M y  1972. A ten-year e s t u a r i e s : mysid  , A.B., T.E. Bowman, s t r i b u t i o n , v a r i a t i o n e opossum shrimp, Neo s i d a c e a ) . F i s h e r y B u l  of  of of  study of meroplankton i n North shrimp. Chesapeake Science 13:  and D.M. Damkaer. 1974. , and supplemental d e s c r i p t i o n mysis americana (Crustacea:. l e t i n 72:835-84.2.  W i l l i a m s , G.C. 1966. N a t u r a l s e l e c t i o n , r e p r o d u c t i o n , and a refinement of Nat. 100:687-692.  the c o s t of Lack's p r i n c i p l e .  of  Am.  W i l s o n , R.R. 1951. D i s t r i b u t i o n , growth, f e e d i n g h a b i t s , abundance, t h e r m a l , and s a l i n i t y r e l a t i o n s of Neomysis mercedis (Holmes) from the N i c k o m e k l and S e r p e n t i n e R i v e r s , B r i t i s h Columbia. M.A. T h e s i s , U n i v e r s i t y of B r i t i s h Columbia, Vancouver.  Wittman m M B  n a e i  , K.J. 1981a. Comparative b i o l o g y and r s u p i a l development i n Leptomysis and diterranean Mysidacea ( C r u s t a c e a ) . J . o l . e c o l . 52:243-270.  Wittmann, K.J m a r s u p i (Mysida e f f e c t s B i o l . e  morphology other exp. mar.  of  . 1 9 8 1 b . On the b r e e d i n g b i o l o g y and p h y s i o l o g y a l development i n Mediterranaen Leptomysis cea: Crustacea) w i t h s p e c i a l r e f e r e n c e to the of temperature and egg s i z e . J . exp. mar. c o l . 53:261-279.  of  1 92  Y o d z i s ,  P.  1981.  f i t n e s s Ecology  Concerning  i s e q u i v a l e n t 62:1681-1682.  the t o  sense  i n which  maximizing  maximizing  r e p r o d u c t i v e  value,  

Cite

Citation Scheme:

        

Citations by CSL (citeproc-js)

Usage Statistics

Share

Embed

Customize your widget with the following options, then copy and paste the code below into the HTML of your page to embed this item in your website.
                        
                            <div id="ubcOpenCollectionsWidgetDisplay">
                            <script id="ubcOpenCollectionsWidget"
                            src="{[{embed.src}]}"
                            data-item="{[{embed.item}]}"
                            data-collection="{[{embed.collection}]}"
                            data-metadata="{[{embed.showMetadata}]}"
                            data-width="{[{embed.width}]}"
                            async >
                            </script>
                            </div>
                        
                    
IIIF logo Our image viewer uses the IIIF 2.0 standard. To load this item in other compatible viewers, use this url:
http://iiif.library.ubc.ca/presentation/dsp.831.1-0096613/manifest

Comment

Related Items