UBC Theses and Dissertations

UBC Theses Logo

UBC Theses and Dissertations

The analysis of zooplankton population fluctuations in the strait of Georgia, with emphasis on the relationships… Gardner, Grant Allan 1976

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

Item Metadata

Download

Media
831-UBC_1976_A1 G37.pdf [ 8.18MB ]
Metadata
JSON: 831-1.0094027.json
JSON-LD: 831-1.0094027-ld.json
RDF/XML (Pretty): 831-1.0094027-rdf.xml
RDF/JSON: 831-1.0094027-rdf.json
Turtle: 831-1.0094027-turtle.txt
N-Triples: 831-1.0094027-rdf-ntriples.txt
Original Record: 831-1.0094027-source.json
Full Text
831-1.0094027-fulltext.txt
Citation
831-1.0094027.ris

Full Text

THE ANALYSIS OF ZOOPLANKTON POPULATION FLUCTUATIONS IN THE STRAIT OF GEORGIA, WITH EMPHASIS ON THE RELATIONSHIPS BETWEEN CALANUS PLUMCHRUS MARUKAWA AND CALANUS MARSHALLAE FROST  by  GRANT ALLAN GARDNER B.Sc, U n i v e r s i t y of Guelph, 1970 M . S c , U n i v e r s i t y o f B r i t i s h Columbia,  1973  A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY  xn  THE FACULTY OF GRADUATE STUDIES Department o f Z o o l o g y and I n s t i t u t e o f Oceanography  We a c c e p t t h i s t h e s i s a s c o n f o r m i n g to t h e required standard  THE UNIVERSITY OF BRITISH COLUMBIA October,  1976  Grant A l l a n Gardner, 1976  In  presenting  this  thesis  an a d v a n c e d d e g r e e the I  Library  further  for  shall  agree  at  in p a r t i a l  the U n i v e r s i t y  make  it  freely  that permission  his representatives.  of  this  thesis  for  It  financial  Zoology  The  of  University  British  2075 W e s b r o o k P l a c e V a n c o u v e r , Canada V6T 1WS  Date  October 5, 1976  of  Columbia,  British for  for extensive  gain  Columbia  the  requirements  reference copying of  I  agree  and this  shall  c o p y i n g or  n o t be a l l o w e d  for  that  study. thesis  by t h e Head o f my D e p a r t m e n t  i s understood that  written permission.  Department o f  of  available  s c h o l a r l y p u r p o s e s may be g r a n t e d  by  fulfilment  or  publication  w i t h o u t my  i  ABSTRACT In 1971,  changes were observed i n t h e o v e r w i n t e r i n g p o p u l a t i o n  s i z e s o f C a l a n u s plumchrus Marukawa, Galanus m a r s h a l l a e F r o s t and C a l a nus p a c i f i c u s c a l i f o r n i c u s Brodsky i n t h e S t r a i t o f G e o r g i a , B r i t i s h Columbia.  C a l a n u s p l u m c h r u s and C. p a c i f i c u s were l e s s common t h a n i n  p r e v i o u s y e a r s , w h i l e C. m a r s h a l l a e was more common.  Based on s c a t t e r e d  d a t a taken s i n c e t h e t u r n o f t h e c e n t u r y , t h e s e changes appeared abnormal.  Because C a l a n u s plumchrus c o n s t i t u t e d  t o be  a s i g n i f i c a n t propor-  t i o n o f t h e biomass o f t h e z o o p l a n k t o n community, i t was p o s s i b l e  that  t h e observed f l u c t u a t i o n s were i n d i c a t i v e o f changes i n t h e s t r u c t u r e o f t h e z o o p l a n k t o n community w i t h i n t h e S t r a i t .  Thus a unique o p p o r t u n i t y  was p r e s e n t e d t o s t u d y a z o o p l a n k t o n community and I t s r e l a t i o n s h i p t o environmental  parameters.  Multiple correlation analysis, cluster analysis, multiple  regression  a n a l y s i s , f a c t o r a n a l y s i s and p r i n c i p a l components a n a l y s i s were used t o a n a l y s e z o o p l a n k t o n c o n c e n t r a t i o n s and h y d r o g r a p h i c d a t a t a k e n i n o v e r w i n t e r i n g p e r i o d s from I969 t o 197^-  A d d i t i o n a l h y d r o g r a p h i c d a t a were  used t o examine r e l a t i o n s h i p s between p h y s i c a l and b i o l o g i c a l d a t a t h r e e and s i x months out o f phase.  The m u l t i v a r i a t e t e c h n i q u e s a l l o w e d an e f f i -  c i e n t a n a l y s i s o f t h e r e l a t i o n s h i p s w i t h i n and between t h e b i o l o g i c a l and p h y s i c a l d a t a banks.  More than one m u l t i v a r i a t e method was used a s each  method g i v e s a s l i g h t l y d i f f e r e n t v i e w p o i n t on t h e d a t a .  A combination  of methods t h u s produces a more complete p i c t u r e o f t h e system b e i n g anal y s e d , w h i l e p o i n t s o f o v e r l a p between t h e t e c h n i q u e s a c t a s i n t e r n a l checks on t h e c o n s i s t e n c y o f t h e a n a l y s i s . The a n a l y s i s i n d i c a t e s a r e c e n t s h i f t i n t h e h y d r o g r a p h i c  regime  ii  of t h e S t r a i t o f G e o r g i a .  The s h i f t i s most o b v i o u s i n t h e s a l i n i t y , b u t  can a l s o be seen i n t h e t e m p e r a t u r e , and i n b o t h c a s e s i s s t r o n g e s t i n S t r a i t o f G e o r g i a deep water. and temperature s t r u c t u r e .  I t i n v o l v e s s u b t l e changes i n s a l i n i t y  These changes axe o f u n c e r t a i n b i o l o g i c a l  sig-  n i f i c a n c e b u t i n d i c a t e f l u c t u a t i o n s i n t h e p r o c e s s o f deep w a t e r f o r m a t i o n . Deep water i s formed i n t h e S o u t h e r n Passages by t h e m i x i n g o f i n c o m i n g S t r a i t o f Juan de F u c a i n t e r m e d i a t e and deep water w i t h o u t f l o w i n g n e a r s u r f a c e f r e s h e r water.  Changes i n e i t h e r o f t h e s e components, o r i n t h e  degree o f m i x i n g , may produce some changes i n t h e q u a l i t y o f t h e deep water, which i n t r u d e s i n t o t h e S t r a i t o f G e o r g i a i n l a t e summer.  These  changes i n q u a l i t y appear t o a f f e c t t h e z o o p l a n k t o n community. I n d i v i d u a l z o o p l a n k t o n s p e c i e s a r e s t r o n g l y i n f l u e n c e d by temperat u r e and s t a b i l i t y c h a r a c t e r i s t i c s o r r e l a t e d f a c t o r s .  Temperature and  s t a b i l i t y d u r i n g the f a l l i n t r u s i o n are p a r t i c u l a r l y important t o the o v e r w i n t e r i n g z o o p l a n k t o n community t h r e e months l a t e r .  The same two  f a c t o r s i n s p r i n g a l s o a f f e c t zooplankton i n the f o l l o w i n g winter.  The  c o n c e n t r a t i o n s o f C a l a n u s plumchrus and C. m a r s h a l l a e have s i g n i f i c a n t (p^O.05) l i n e a r r e g r e s s i o n s w i t h c o n c u r r e n t t e m p e r a t u r e a t 350  m.  The  r e g r e s s i o n l i n e s have o p p o s i t e s l o p e s and i n t e r s e c t i n t h e r e g i o n o f n o r mal ambient t e m p e r a t u r e a t 350 m.  T h i s r e s u l t s u g g e s t s t h a t deep water  temperature, o r a t e m p e r a t u r e a s s o c i a t e d , f a c t o r , s t r o n g l y a f f e c t s t h e r e l a t i v e f l u c t u a t i o n s i n t h e numbers o f b o t h s p e c i e s . P r i n c i p a l components and f a c t o r a n a l y s i s o f t h e h y d r o g r a p h i c d a t a b o t h suggest t h a t t h e most i m p o r t a n t f a c t o r i n t h e s t r u c t u r e o f t h e water column i s i t s s u b d i v i s i o n i n t o n e a r s u r f a c e , i n t e r m e d i a t e and deep water. However, i n b o t h temperature and s a l i n i t y components a p o r t i o n o f t h e  iii  v a r i a n c e i s a s s o c i a t e d w i t h a t e m p o r a l t r e n d w i t h i n t h e deep water. P r i n c i p a l components o f t h e z o o p l a n k t o n s i m i l a r l y a s s o c i a t e 15% o f t h e zooplankton v a r i a n c e w i t h a temporal t r e n d . weighted  No s p e c i e s i s s t r o n g l y  on t h e s e components, and t h e a s s o c i a t i o n appears t o be a f u n c t i o n  o f t h e whole community, r a t h e r t h a n o f i n d i v i d u a l s p e c i e s . As an a d j u n c t t o t h i s i n v e s t i g a t i o n , e c o l o g i c a l s e p a r a t i o n between Calanus plumchrus and C. m a r s h a l l a e was i n v e s t i g a t e d . s i m i l a r d i s t r i b u t i o n s and l i f e h i s t o r i e s .  B o t h s p e c i e s have  F e e d i n g c o m p e t i t i o n between  them i s m i n i m i z e d by a s e p a r a t i o n i n t h e i r a b i l i t y t o f i l t e r s m a l l p a r t i c l e s from t h e water.  Calanus plumchrus can f e e d r e a d i l y on p a r t i c l e s  above 3>5 ym i n d i a m e t e r , w h i l e C. m a r s h a l l a e can n o t e f f i c i e n t l y p a r t i c l e s below about 10.5  ym i n d i a m e t e r .  Thus, C a l a n u s plumchrus can  e x p l o i t a p o t e n t i a l l y r i c h f o o d source w i t h no c o m p e t i t i o n from marshallae.  filter  Calanus  T h i s advantage may m a i n t a i n C a l a n u s plumchrus w i t h i n t h e  S t r a i t of G e o r g i a d e s p i t e t h e d e t r i m e n t a l e f f e c t o f a s h i f t i n deep water temperature  or related factors.  I t a l s o s u g g e s t s t h a t , g i v e n a more  "normal" p h y s i c a l c l i m a t e , Calanus plumchrus c o u l d r e v e r t t o i t s t r a d i t i o n a l dominance. I f Calanus plumchrus c o n t i n u e s t o drop, o r r e m a i n s a t s u p p r e s s e d l e v e l s , t h e e c o n o m i c a l l y i m p o r t a n t f i s h s p e c i e s t h a t u t i l i z e i t as f o o d w i l l have t o s h i f t p r e y s p e c i e s , p r o b a b l y t o Calanus m a r s h a l l a e .  Feeding  on C. m a r s h a l l a e w i l l i n v o l v e a g r e a t e r energy e x p e n d i t u r e t o o b t a i n t h e same r a t i o n , and may be d e t r i m e n t a l t o some p r e d a t o r s .  iv  TABLE OF CONTENTS ABSTRACT  i  LIST OF FIGURES  v i i  LIST OF TABLES  viii  ACKNOWLEDGEMENTS  x  GENERAL INTRODUCTION  1  THE STUDY AREA  11  DESCRIPTION AND ANALYSIS OF STRAIT OF GEORGIA ZOOPLANKTON Introduction  1?  Sample C o l l e c t i o n and A n a l y s i s Introduction  19  Procedure  19  E v a l u a t i o n of sampling gear  222  Statistical  Methodology  Introduction Data treatment  24'  26  S t a t i s t i c a l procedures  28  Evaluation of technigues  31  Results H y d r o g r a p h i c regime d u r i n g t h e s t u d y p e r i o d  39  R e s u l t s o f sample s o r t i n g  4-6  D i v e r s i t y and m u l t i p l e c o r r e l a t i o n  53  Cluster analysis  53  Canonical c o r r e l a t i o n  58  Regression a n a l y s i s  59  Factor analysis  63  V  P r i n c i p a l components a n a l y s i s  * 65  Discussion Data manipulation  74-  D i v e r s i t y and m u l t i p l e c o r r e l a t i o n a n a l y s i s  75  Cluster analysis  77  Canonical c o r r e l a t i o n analysis  79  Regression a n a l y s i s  83  F a c t o r and p r i n c i p a l components a n a l y s i s  88  ASPECTS OF THE ECOLOGY OF THE APPARENTLY CO-OCCURRING SPECIES CALANUS PLUMCHRUS MARUKAWA AND CALANUS MARSHALLAE FROST Introduction  96  Distribution  98  Feeding Introduction  99  Procedure  99  R e a r i n g and B r e e d i n g Introduction Procedure  101 101 v  Calorimetry Introduction Procedure  102 104-  Results Distribution  105  Feeding  105  R e a r i n g and b r e e d i n g  110  vi  Galorimetry  112  Discussion  113  SUMMARY  125  REFERENCES'  129  APPENDIX A  144  vii  LIST OF FIGURES F i g u r e 1:  F i g u r e 2:  D i s t r i b u t i o n of major c u r r e n t s i n t h e o c e a n i c r e g i o n adjacent t o the study area  12  The s t u d y a r e a and i t s major d i v i s i o n s  13  F i g u r e 3^a-e): F i g u r e 4-(a-e): F i g u r e 5: F i g u r e 6:  Temperature i s o p l e t h s f o r f i v e c o n s e c u t i v e y e a r s a t Geo 174-8 S a l i n i t y isopTeths f o r f i v e consecutive y e a r s a t Geo 174-8  F l u c t u a t i o n s i n s a l i n i t y at s e l e c t e d depths i n s u c c e s s i v e Decembers a t Geo 174-8  4-0 4-1 4-3  Summary of t h e c o r r e l a t i o n c o e f f i c i e n t s between the zooplankton species i n the b a s i c dataamatrix  54-  F i g u r e 7:  Clustering  o f t h e p a r t i t i o n e d months  55  F i g u r e 8:  Clustering  o f s p e c i e s , p a r t i t i o n e d raw d a t a  57  F i g u r e 9:  R e g r e s s i o n of C a l a n u s plumchrus and C. m a r s h a l l a e  F i g u r e 10:  a g a i n s t temperature a t 350 m V e r t i c a l d i s t r i b u t i o n of C a l a n u s plumchrus and C. m a r s h a l l a e d u r i n g o v e r w i n t e r i n g  106  Second m a x i l l a e o f Calanus plumchrus and Calanus m a r s h a l l a e . Major d i s t i n c t f i l t e r i n g zones a r e shown i n o u t l i n e  107  F i l t e r i n g e f f i c i e n c y c u r v e s f o r Calanus plumchrus and C a l a n u s m a r s h a l l a e  109  F i g u r e 11:  F i g u r e 12:  64  viii  LIST OF TABLES Table I:  D i v e r s i t y i n d i c e s and t h e i r methods o f c a l c u l a t i o n  29  Table I I :  L i s t o f a l l s p e c i e s o r groups s o r t e d  4-7  Table I I I :  P r o p o r t i o n ^ each s p e c i e s i n each o f t h e r e g i o n s of t h e water column found a t Geo 1748  4-9  The c o n c e n t r a t i o n s (no./m ) o f t h e t h r e e C a l a n u s s p e c i e s d u r i n g t h e study p e r i o d  51  E f f e c t o f t r a n s f o r m i n g t h e raw d a t a on two s p e c i e s and two months chosen a t random from t h e d a t a matrix  52  The numbers o f s i g n i f i c a n t p o s i t i v e and n e g a t i v e c o r r e l a t i o n c o e f f i c i e n t s i n the species correlation matrix  53  G r o u p i n g o f s p e c i e s by v e r t i c a l d i s t r i b u t i o n pattern  58  T a b l e IV: T a b l e V:  Table VI:  Table V I I :  T a b l e V I I I : Summary o f t h e s i g n i f i c a n t c a n o n i c a l c o r r e l a t i o n coefficients Table IX:  T a b l e X:  Summary o f a l l r e g r e s s i o n e q u a t i o n s s i g n i f i c a n t at F = 0.10 prob I n i t i a l f a c t o r i n g of z o o p l a n k t o n d a t a  Table X I :  Secondary f a c t o r i n g of s p e c i e s a s s o c i a t e d w i t h t h e  P r i n c i p a l components of the h y d r o g r a p h i c d a t a (  T a b l e X I I I : Rank o r d e r o f s t a n d a r d i z e d c a s e s on each p r i n c i p a l component T a b l e XIV: P r i n c i p a l components a n a l y s i s o f t h e p a r t i t i o n e d zooplankton data T a b l e XV: T a b l e XVI:  61,  66  67  f i r s t f a c t o r of Table X Table X I I :  60  F i l t r a t i o n zone a n a l y s i s of t h e second m a x i l l a e o f C a l a n u s plumchrus and C. m a r s h a l l a e Development t i m e s and growth r a t e s of C a l a n u s plumchrus a t 8 C  T a b l e X V I I : O v e r a l l growth r a t e s f o r C a l a n u s plumchrus r e a r e d i n t h e l a b o r a t o r y , e x p r e s s e d as p e r cent change i n weight p e r day  68  70 72 105  I l l  I l l  62  ix  T a b l e X V I I I : Average c a l o r i f i c v a l u e p e r u n i t d r y weight and per i n d i v i d u a l  109  X  ACKNOWLEDGEMENTS I t i s a p l e a s u r e t o acknowledge t h e a s s i s t a n c e and guidance Dr. A.G.  which  L e w i s has p r o v i d e d d u r i n g my t e n u r e a t t h e U n i v e r s i t y of B r i t i s h  Columbia.  D r s . R.E.  Foreman, G.C.  Hughes, C.J. Krebs, T.R.  Parsons  and  S. Pond a l s o gave v a l u a b l e a s s i s t a n c e b o t h i n my r e s e a r c h and i n t h e p r e p a r a t i o n of t h i s t h e s i s .  They have r e a d t h e m a n u s c r i p t  and any e r r o r s t h a t r e m a i n a r e w h o l l y my  critically,  own.  I w i s h t o extend my thanks t o a l l of t h e members o f t h e I n s t i t u t e of Oceanography f o r p r o v i d i n g t h e s t i m u l a t i n g atmosphere t h a t makes i n t e r d i s c i p l i n a r y r e s e a r c h b o t h i n t e r e s t i n g and e x c i t i n g , and i n p a r t i c u l a r t o A. Ramnarine and M.P.  Storm who  h e l p e d t o smooth out  many of t h e t e c h n i c a l problems t h a t might o t h e r w i s e have made t h e l e c t i o n o f d a t a much more d i f f i c u l t and c e r t a i n l y l e s s  col-  interesting.  The g a t h e r i n g o f samples f r o m over a f i v e y e a r p e r i o d o f n e c e s s i t y i n v o l v e s the a s s i s t a n c e and c o - o p e r a t i o n o f a g r e a t many p e o p l e . t h e s e p e o p l e , s p e c i a l thanks go t o Dr. M.S. who  c o l l e c t e d many o f t h e samples.  d i a n Hydrographic  Evans and Mr. D.P.  Among  Stone,  The o f f i c e r s and crew o f t h e Cana-  S e r v i c e s h i p s V e c t o r and P a r i z e a u , and o f t h e Canadian  Navy s h i p Laymore, were a l s o o u t s t a n d i n g i n t h e i r c o - o p e r a t i o n and h e l p fulness.  I n p a r t i c u l a r , a l l of t h e o f f i c e r s and crew who  on t h e C.S.S. V e c t o r a h a v e  have s e r v e d  a c t e d w i t h c h e e r f u l n e s s and w i l l i n g n e s s under  a l l c o n d i t i o n s o f weather and sea s t a t e t o make t h e c o l l e c t i o n o f samples not j u s t p o s s i b l e , b u t p l e a s a n t and  exciting.  Much of my r e s e a r c h was funded by NRC Lewis.  A-206?, a g r a n t t o Dr.  A.G.  P e r s o n a l f u n d i n g was a l s o o b t a i n e d f r o m t h e N a t i o n a l Research  C o u n c i l o f Canada, v i a an NRC  s c h o l a r s h i p i n 1970/71, and f r o m t h e  Department o f Zoology, UBC, v i a a s e r i e s o f T e a c h i n g  Assistantships.  The g r e a t e s t thanks o f a l l must go t o my w i f e , B e v e r l e y , who p e r s e v e r e d t h r o u g h t h o s e y e a r s when t h e end seemed out o f s i g h t . W i t h o u t h e r c o n t i n u e d s u p p o r t , encouragement and good s p i r i t s , t h e d i f f i c u l t i e s i n v o l v e d i n p r e p a r i n g f o r t h e Ph .D. d e g r e e would have been m a g n i f i e d t e n f o l d .  1  GENERAL INTRODUCTION I n 1971>  a change was n o t e d I n t h e l o c a l p o p u l a t i o n l e v e l s o f t h r e e  c o n g e n e r i c s p e c i e s o f p l a n k t o n i c marine copepod. Calanus plumchrus,  One o f t h e s e s p e c i e s ,  i s a major source o f f o o d f o r h e r r i n g , salmon and  o t h e r p l a n k t i v o r e s (Campbell 1933; L e b r a s s e u r e t a l . I969), and i n t h e s p r i n g can r e a c h numbers s u f f i c i e n t t o c r e a t e a monomyctic s i t u a t i o n i n c e r t a i n areas of the S t r a i t of Georgia (Parsons, LeBrasseur e t a l . I969).  I n November 19711 t h e abundance o f t h i s s p e c i e s was observed t o  be about an o r d e r o f magnitude l e s s than i t s abundance i n December I969 and December 1970 ( F u l t o n , p e r s . comm.; Gardner 1972). t h e p o p u l a t i o n o f C a l a n u s p a c i f i c u s appeared  Simultaneously,  t o have d e c r e a s e d w h i l e t h e  p o p u l a t i o n o f C. m a r s h a l l a e appeared t o have i n c r e a s e d .  Other d a t a  ( e . g . Stephens e t a l . 19&9) e s t a b l i s h t h a t t h e o v e r w i n t e r i n g l e v e l s o f C. plumchrus were s t a b l e f o r a t l e a s t t h e f i v e y e a r s p r e c e d i n g t h e decline.  S i m i l a r d a t a do n o t e x i s t f o r t h e o t h e r two Calanus s p e c i e s , a s  t h e y were n o t c o n s i d e r e d s e p a r a t e s p e c i e s i n t h e S t r a i t o f G e o r g i a  until  I969 (Woodhouse 1971) • O b s e r v a t i o n s on C. plumchrus were s p o r a d i c p r i o r t o 1965.  The  d a t a t h a t do e x i s t ( e . g . Campbell 1933i 193^-) c o n s i d e r C. plumchrus t o be t h e dominant l o c a l z o o p l a n k t o n s p e c i e s , and t h e o v e r w i n t e r i n g l e v e l s o f t h e s p e c i e s appear t o have been c o n s i s t e n t l y h i g h e r than t h o s e observed I n f a l l 1971•  T h i s s t r o n g l y suggests t h a t t h e l o w numbers i n 1971  c o n s t i t u t e an "abnormal"  e c o l o g i c a l event i n t h a t t h e y do n o t r e f l e c t  t h e b e h a v i o u r o f t h e p o p u l a t i o n over t h e l a s t h a l f - c e n t u r y . F u l t o n (1973; p e r s . comm;) s u g g e s t s t h a t t h e i n f e c t i o n o f C. plumchrus by t h e p a r a s i t i c y e a s t M e t s c h n i k o w i a sp. may have i n i t i a t e d o r c o n t r i b u t e d t o  2  the decline, but the s i g n i f i c a n c e of the yeast i n the S t r a i t of Georgia has yet to be established.  The presence of the yeast, however, i n  addition t o t h e concurrent population f l u c t u a t i o n s of Calanus marshallae 1  and C. p a c i f i c u s , further suggests that the decline of Calanus plumchrus i s not an isolated event and that a change i n the r e l a t i v e importance of the three species might be occurring. Copepods constitute the predominant c l a s s within the marine zooplankton (Raymont 1963; T a i t I968).  Consequently,  changes i n the popula-  t i o n l e v e l s of, and ..in the interactions between, copepod species can have a pronounced e f f e c t on the structure of the zooplankton community as a whole, and by extrapolation can a f f e c t the structure of the marine food chain.  The analysis and description of such population changes w i l l  have both l o c a l and general s i g n i f i c a n c e .  Locally, the importance of the  S t r a i t of Georgia zooplankton as food f o r migrating and developing s a l monids and other commercially important f i s h e s suggests that changes i n the structure of the zooplankton community may have economic as well as e c o l o g i c a l repercussions.  In a more general sense, the analysis of  factors a f f e c t i n g f l u c t u a t i o n s within zooplankton communities w i l l be important to our understanding of the dynamics of such communities both i n estuaries and i n the open ocean. Seasonal and annual fluctuationss i n species and communities have been investigated previously from many d i f f e r e n t viewpoints, but our understanding of such fluctuations i s s t i l l f a r from complete.  Never-  theless, certain conclusions can be drawn which apply to population,:s ftLugiisAiations i n general. Fluctuations i n the population l e v e l of a species are not unusual  3  on a seasonal time scale, and are i n t u i t i v e l y more acceptable  than  stable population l e v e l s or populations that follow a smooth, sigmoid curve (Slobodkin 1954-)•  Furthermore, the f l u c t u a t i o n s should be more  pronounced i n a more widely varying environment.  The complexity of  food webs and the constancy of the environment i n t r o p i c a l areas w i l l tend to dampen o s c i l l a t i o n s ; however, the r e l a t i v e s i m p l i c i t y of food webs and the pronounced seasonality of the environment i n temperate and polar climates w i l l r e i n f o r c e o s c i l l a t i o n s (Dunbar i 9 6 0 ) . Heinrich (1962b), f o r example, has described d i f f e r e n t types of seasonal cycle in the zooplankton of A r c t i c and north temperate waters. The cycles which he describes are a l l characterized by at l e a s t peak in abundance during the year.  one  The v a r i a t i o n within such cycles  i s associated with the pronounced seasonality of the phytoplankton (Raymont 1963;  Parsons and Takahashi 1973), which i n turn w i l l be gov-  erned by the seasonality of the p h y s i c a l environment.  In n e r i t i c habi-  t a t s , geographic, t i d a l and runoff considerations also become important factors and may  complicate  the analysis of seasonal f l u c t u a t i o n s (Par-  sons and Takahashi 1973)• O s c i l l a t i o n s i n the population l e v e l s of s i n g l e species over multiyear periods are also well known.  Although most of the species studied  have been t e r r e s t r i a l (e.g. A r c t i c fox and lemmings: Elton 194-2; wolf: Cole 1951;  tent c a t e r p i l l a r s : Wellington  1957,  I960; locusts: Waloff  I966, cited by Odum 1971), such f l u c t u a t i o n s have also been noted in aquatic organisms (e.g. Sears and Clarke 194-0; Slobodkin i960).  195^;  In :one of the most extensive studies of the population  Dunbar fluctu-  ations in a marine plankton community, Sears and Clarke (194-0) monitored  4  l a r g e a m p l i t u d e f l u c t u a t i o n s i n t h e z o o p l a n k t o n s p e c i e s on t h e c o n t i n e n t a l s h e l f i n t h e Gape God a r e a .  The a r e a m o n i t o r e d was h y d r o g r a p h i c a l l y  r e l a t i v e l y s t a b l e f r o m y e a r t o y e a r , and t h e r e was no a p p a r e n t e n v i r o n mental c o n t r o l over t h e observed f l u c t u a t i o n s i n p o p u l a t i o n s i z e s .  The  S e a r s and C l a r k e a n a l y s i s i s l a r g e l y d e s c r i p t i v e ; t h e y appear t o have "b been i n v e s t i g a t i n g a system c h a r a c t e r i z e d by l a r g e y e a r t o y e a r f l u c t u a t i o n s i n numbers o f many o f i t s s p e c i e s .  A l t h o u g h S e a r s and C l a r k e f e l t  t h a t t h e s e f l u c t u a t i o n s were o f b a s i c i m p o r t a n c e , t h e y were unable t o e s t a b l i s h a cause f o r them. I n t h e s e and s i m i l a r s t u d i e s , t h e r e h a s been a tendancy t o approach t h e problem on a s p e c i e s l e v e l .  A l t h o u g h i t i s p r o f i t a b l e t o examine  such f l u c t u a t i o n s f r o m an a u t e c o l o g i c a l v i e w p o i n t , t h e i r p o s s i b l e r a m i f i c a t i o n s suggest u s i n g an approach t h a t w i l l y i e l d more i n f o r m a t i o n on p o p u l a t i o n and community p r o c e s s e s .  There have u n f o r t u n a t e l y been f e w  a t t e m p t s t o d i s c u s s such f l u c t u a t i o n s i n terms o f t h e i r e f f e c t on t h e K zooplankton, phytoplankton o r p e l a g i c  communities.  C l a r k e (195^) emphasized t h a t a t t e m p t s t o d i s c o v e r t h e causes and e f f e c t s o f f l u c t u a t i o n s i n communities o f organisms have n o t been v e r y successful.  M u l t i y e a r changes i n p o p u l a t i o n l e v e l s , and t h e i r e f f e c t  on community s t r u c t u r e i n a l a r g e , m o d e r a t e l y s t r a t i f i e d e s t u a r y such a s t h e S t r a i t o f G e o r g i a , have n o t been s t u d i e d .  To a t t a c k t h i s problem,  and t o i n v e s t i g a t e r e l a t i o n s h i p s w i t h i n a community, f i r s t  requires  c l a r i f i c a t i o n o f t h e concept o f "community" a s i t a p p l i e s t o marine ecosystems. M i l l s (1969) r e v i e w e d t h e community concept i n marine z o o p l a n k t o n and i n o t h e r a n i m a l assemblages.  He found t h a t t h e term "community" had  5  been used i n many d i f f e r e n t ways, and that i t was impossible to decide which view was most meaningful or whether there were other views that were more meaningful.  Despite t h i s ambiguity, M i l l s proposed that the  term be retained, rather than replaced with a series of new terms, and suggested defining a community as "...a group of organisms occurring i n a p a r t i c u l a r environment,  and separable, by means of e c o l o g i c a l survey,  from other groups." T r a d i t i o n a l l y , studies of communities,  l i k e studies of population  f l u c t u a t i o n s , have been based more frequently on t e r r e s t r i a l than aquatic ecosystems because of the r e l a t i v e a c c e s s i b i l i t y of suitable study areas and our greater f a m i l i a r i t y with "dry land" (e.g. Grombie 1947; Elton 19^6; Elton and M i l l e r 1 9 5 * 0 •  T e r r e s t r i a l organisms are often d i s t r i -  buted i n an approximately two-dimensional space, and are more r e a d i l y obtained and maintained i n the laboratory than are most marine organisms. Furthermore, h i s t o r i c a l records of species occurrences are l i k e l y more complete than f o r marine species, and borders between neighbouring habit a t s are often more r e a d i l y defined.  In the marine environment,  study of communities i s more d i f f i c u l t .  the s t  When the communities are s t i l l  confined to a nearly two-dimensional space, as i n i n t e r t i d a l and benthic organisms, t h e i r study may be approached  i n much the same manner as i s  used f o r the study of t e r r e s t r i a l organisms (e.g. Odum and Smalley 1959; Vinogradova 1959; Gonnell 196la, b; Thorson I966).  When the organisms  are planktonic, t h e i r analysis becomes very complicated. M i l l s ' d e f i n i t i o n assumes that the environment be expressed by an array of suitable parameters.  of a community can  In t e r r e s t r i a l commu-  n i t i e s , these parameters can be components of the substratum type,  6  micro-climate, variables.  v e g e t a t i o n t y p e w i t h i n the range or s i m i l a r complex  I n t e r t i d a l communities a r e o f t e n d e f i n e d p a r t i a l l y i n terms  of s u b s t r a t u m t y p e and  t i d a l regime.  p l a n k t o n i c community, which i s a r r a y e d  D e f i n i n g the environment o f a i n a three-dimensional  space  and b o r d e r e d by c l o s e l y s i m i l a r environments, i s l e s s s t r a i g h t f o r w a r d . The development o f methods by which t h e marine environment c o u l d be " c o m p a r t m e n t a l i z e d " i n a manner s u i t a b l e f o r community a n a l y s i s began with the e a r l i e s t extensive ton.  e c o l o g i c a l i n v e s t i g a t i o n s of marine z o o p l a n k -  I n i t i a l l y , t h i s work i n v o l v e d the i n v e s t i g a t i o n of a s s o c i a t i o n s  between d i s c r e t e assemblages of s p e c i e s and  i d e n t i f i a b l e b o d i e s of  R u s s e l l ' s work i n t h e B r i t i s h I s l e s (1935, 1936a, b; 1939) p r o -  water.  vided the basis f o r thist&ype  of work, and B a r y (1959. 1963a, b, c; 1964)  f u r t h e r d e v e l o p e d t h e t e c h n i q u e of u s i n g s p e c i e s - w a t e r  body r e l a t i o n s h i p s  t o i n v e s t i g a t e s p e c i e s ' a s s o c i a t i o n s and d i s t r i b u t i o n p a t t e r n s . a p p l i e d t h i s t e c h n i q u e over a l a r g e g e o g r a p h i c a r e a , and  Bary  delineated  t h r e e d i s t i n c t t y p e s of water and a s s o c i a t e d groups of z o o p l a n k t o n i n the w a t e r s o f the A t l a n t i c Ocean n o r t h and The  e a s t of B r i t a i n .  factors responsible f o r maintaining  a species-water  mass a s s o c i -  W i l s o n (1951) demonstrated d i f f e r e n c e s between  a t i o n a r e s t i l l unknown.  water b o d i e s by showing t h a t water from t h e E n g l i s h Channel and from t h e C e l t i c Sea had  s i g n i f i c a n t l y d i f f e r e n t e f f e c t s on t h e r e a r i n g  of a q u a t i c i n v e r t e b r a t e s . 1958,  water  F u r t h e r e x p e r i m e n t s ( W i l s o n and  Armstrong  I96I) showed t h a t the p r o p e r t i e s r e s p o n s i b l e v a r i e d t e m p o r a l l y  t h e same l o c a l i t y , as w e l l as v a r y i n g g e o g r a p h i c a l l y , but t h e i n v o l v e d c o u l d n o t be i s o l a t e d .  in  properties  B a r y (1964) has a l s o p o s t u l a t e d  e x i s t e n c e of such p r o p e r t i e s or groups of p r o p e r t i e s , but c o u l d  the not  7  c o r r e l a t e them w i t h any known c h e m i c a l o r p h y s i c a l p a r a m e t e r s o f t h e water body. Despite the i n a b i l i t y t o determine the f a c t o r s r e s p o n s i b l e f o r v a r i a t i o n s i n water q u a l i t y , t h e s p e c i e s - w a t e r body approach i s s t i l l v a l i d and has been w i d e l y used I n t h e P a c i f i c - n o t a b l y by B i e r i L e B r a s s e u r ( 1 9 5 9 ) , Aron ( 1 9 6 2 ) and F a g e r and McGowan ( 1 9 6 3 ) .  (1959),  The d e v e l -  opment o f t e c h n i q u e s f o r examining t h e d i s t r i b u t i o n o f organisms w i t h r e s p e c t t o water b o d i e s has g i v e n t h e b i o l o g i c a l oceanographer t h e a b i l i t y t o d i f f e r e n t i a t e e c o l o g i c a l l y unique a r e a s o f t h e environment and t o i d e n t i f y s p e c i e s groups a s s o c i a t e d w i t h such a r e a s .  U n t i l the  f a c t o r s o p e r a t i n g t o make t h e s e a r e a s d i s t i n c t a r e known, however, t h e s t u d y o f marine z o o p l a n k t o n communities w i l l be hampered.  Nevertheless,  t h e i n v e s t i g a t i o n o f s p e c i e s i n t e r r e l a t i o n s h i p s and community dynamics, b o t h from p r a c t i c a l and t h e o r e t i c a l v i e w p o i n t s , has proceeded r a p i d l y i n r e c e n t y e a r s ( e . g . H e i n r i c h 1 9 6 2 a , b; A n r a k u and Omori 1 9 6 2 ; 1963,  Mullin  I 9 6 8 ; B r o o k s and Dodson I 9 6 5 ; J e f f r i e s I 9 6 7 ; G e y n r i k h I 9 6 8 ; I k e d a  1 9 7 0 ; Hodgkin and R i p p i n g a l e 1 9 7 1 ; The i n v e s t i g a t i o n  S a i l a and P a r r i s h 1 9 7 2 ;  Fager 1 9 7 3 ) .  o f t h e z o o p l a n k t o n community o f t h e S t r a i t o f  G e o r g i a has n o t proceeded a t t h e same r a t e as the s t u d y o f z o o p l a n k t o n communities i n o t h e r a r e a s .  L o c a l l y , most o f the p r e v i o u s work i s  e i t h e r t e m p o r a l l y r e s t r i c t e d and d e a l s w i t h t h e e c o l o g y of o n l y a few s p e c i e s ( e . g . Campbell 1 9 3 3 , e t a l . 1971,. 1 9 7 2 ;  193^;  Gardner 1 9 7 2 ;  Pandyan 1 9 7 1 ;  Evans 1 9 7 3 ;  Woodhouse 1 9 7 1 ;  F u l t o n 1973)  Lewis  o r t r e a t s many  s p e c i e s , p r i m a r i l y i n a taxonomic c o n t e x t ( e . g . Campbell 1 9 2 9 a , b, F u l t o n 1968,  1930;  1972).  The o n l y "comprehensive" p l a n k t o n s u r v e y o f t h e S t r a i t o f G e o r g i a  8  i s t h a t o f Legare  (1957)•  U n f o r t u n a t e l y , L e g a r e ' s d a t a a r e from two  s a m p l i n g p e r i o d s o n l y , and h i s t e c h n i q u e s a r e open t o q u e s t i o n . H i s d e e p e s t n e t h a u l was from 250 m, c o m p l e t e l y . c u t t i n g o f f t h e o v e r w i n t e r i n g p o p u l a t i o n o f C a l a n u s plumchrus ( e . g . G a r d n e r 1972) and p e r h a p s of  other species as w e l l .  0.2 m  The n e t t h a t he used was v e r y s m a l l ( c a ,  mouth a r e a ) and was equipped w i t h a mesh s i z e and t y p e (25xxx  b o l t i n g c l o t h ) t h a t would r e s u l t i n c l o g g i n g and r e j e c t i o n o f water, y i e l d i n g a b i a s e d sample ( e . g . T r a n t e r and F r a s e r 1968).  In addition,  w i t h t h e e x c e p t i o n o f s u r f a c e t e m p e r a t u r e , Legare d i d n o t m o n i t o r any. hydrographic  parameters.  S i n c e Legare&s s u r v e y , t h e P a c i f i c B i o l o g i c a l S t a t i o n i n Nanaimo has c o l l e c t e d a c o n s i d e r a b l e amount o f p h y s i c a l and b i o l o g i c a l d a t a i n t h e S t r a i t o f G e o r g i a ( e . g . Stephens e t a l . I969), b u t t h e d a t a have n o t been f u l l y a n a l y s e d and a r e p r e s e n t e d o n l y a s raw d a t a w i t h l i t t l e interpretation.  P a r s o n s , L e B r a s s e u r and B a r r a c l o u g h (1970) have syn-  t h e s i z e d many o f t h e s e d a t a i n t o a r e v i e w o f p r o d u c t i o n l e v e l s i n t h e S t r a i t of Georgia, but d i s c u s s selected species only.  The p r o d u c t i v i t y  of t h e S t r a i t o f G e o r g i a was examined i n more d e t a i l i n a s e r i e s o f p a p e r s d e a l i n g w i t h p r i m a r y p r o d u c t i o n ( P a r s o n s , Stephens and L e B r a s s e u r 1969)1 secondary p r o d u c t i o n ( P a r s o n s , L e B r a s s e u r e t a l . I969) and f i s h g r a z i n g ( L e B r a s s e u r e t a l . I969). was r e s t r i c t e d t o t h e s p r i n g o f 1967 > t h e F r a s e r R i v e r plume were sampled.  The p e r i o d examined, however, o n  i y near s u r f a c e waters i n  C o n s e q u e n t l y , no e x a m i n a t i o n o f  t h e z o o p l a n k t o n community i n terms o f t e m p o r a l v a r i a t i o n and i n terms o f b a s i c h y d r o g r a p h i c parameters Georgia.  h a s been c a r r i e d o u t i n t h e S t r a i t o f  9  I t i s i m p o r t a n t t o understand and be a b l e t o d e s c r i b e t h e r e l a t i o n s h i p s between z o o p l a n k t o n s p e c i e s w i t h i n a community, and t h e i n t e r a c t i o n between s p e c i e s o r s p e c i e s groups and t h e p h y s i c a l environment.  Further-  more, i t i s e s s e n t i a l t o a s s e s s t h e impact o f t h e apparent s h i f t i n t h e numbers o f t h e t h r e e Calanus s p e c i e s i n t h e S t r a i t o f G e o r g i a on t h e z o o p l a n k t o n community as a whole.  To examine t h e s e a s p e c t s o f t h e  e c o l o g y o f t h e l o c a l z o o p l a n k t o n , I have s o r t e d and counted a s e r i e s o f v e r t i c a l and h o r i z o n t a l tows from an oceanographic of Georgia.  s t a t i o n i n the S t r a i t  The d a t a have been a n a l y s e d by a v a r i e t y o f s t a t i s t i c a l  t e c h n i q u e s d e s i g n e d t o y i e l d t h e maximum amount o f i n f o r m a t i o n on t h e s t r u c t u r e o f t h e z o o p l a n k t o n community and on t h e i n t e r a c t i o n s o f t h e community and i t s component members w i t h t h e h y d r o g r a p h i c regime i n t h e Strait. W i t h i n t h e c o n t e x t o f t h i s study, I have l o o k e d a t t h e e c o l o g i c a l s e p a r a t i o n o f C a l a n u s plumchrus and C. m a r s h a l l a e .  The  co-occurrence  o f c o n g e n e r i c s p e c i e s i s e c o l o g i c a l l y i n t e r e s t i n g and n o t w e l l understood.  Hence, s p e c i f i c . i n f o r m a t i o n r e g a r d i n g t h e r e l a t i o n s h i p s between  t h e t h r e e s p e c i e s o f C a l a n u s commonly found i n t h e S t r a i t o f G e o r g i a i s important i n i t s e l f .  Furthermore,  t h e dominance o f C a l a n u s i n t h e zoo-  p l a n k t o n biomass ( P a r s o n s , L e B r a s s e u r e t a l . 1969;  G a r d n e r 1972)  sug-  g e s t s t h a t c l a r i f y i n g t h e r e l a t i o n s h i p between s p e c i e s o f C a l a n u s i s i m p o r t a n t t o an u n d e r s t a n d i n g o f t h e z o o p l a n k t o n community as a whole. Woodhouse (1971) h a s e s t a b l i s h e d t h a t C a l a n u s m a r s h a l l a e and C. p a c i f i c u s a r e i n f a c t a l l o p a t r i c s p e c i e s ; however, t h e s i m u l t a n e o u s  distributions  o f C. m a r s h a l l a e and C. plumchrus have n o t been f u l l y e s t a b l i s h e d . The importance  o f Calanus plumchrus as a source o f f o o d f o r young  10  salmon i n t h e S t r a i t o f G e o r g i a (Campbell  1933; L e b r a s s e u r e t a l . I969)  suggests t h a t i n t e r a c t i o n s between C. plumchrus and C. m a r s h a l l a e c o u l d a f f e c t t h e g e n e r a l e c o l o g y and economic importance w e l l as the s t r u c t u r e o f the zooplankton p o s s i b l e importance  community.  o f the S t r a i t , as Because o f t h e  o f t h i s i n t e r a c t i o n , I have examined t h e degree o f  o v e r l a p between t h e two s p e c i e s w i t h r e s p e c t t o s e l e c t e d a s p e c t s o f d i s t r i b u t i o n , f e e d i n g and b r e e d i n g .  I n a d d i t i o n , I have examined t h e  r e l a t i v e f o o d v a l u e o f G. plumchrus and C. m a r s h a l l a e i n o r d e r t o e s t i mate t h e e f f e c t on p l a n k t i v o r e s o f a s h i f t i n t h e r e l a t i v e numbers o f t h e two s p e c i e s . These r e s u l t s , i n c o n j u n c t i o n w i t h t h e a n a l y s i s o f p o p u l a t i o n f l u c t u a t i o n s i n t h e o t h e r members o f t h e z o o p l a n k t o n , w i l l be used t o d e s c r i b e t h e e x t e n t and causes o f f l u c t u a t i o n s i n t h e z o o p l a n k t o n community s i n c e 1969-  A unique o p p o r t u n i t y f o r t h i s t y p e o o f  investigation  has been g e n e r a t e d by t h e s h i f t i n t h e p o p u l a t i o n l e v e l s o f t h e t h r e e Calanus s p e c i e s .  The r e s u l t s o f t h i s i n v e s t i g a t i o n w i l l n o t o n l y be o f  v a l u e l o c a l l y , b u t s h o u l d h e l p t o c l a r i f y some o f t h e g e n e r a l p r i n c i p l e s o f z o o p l a n k t o n community e c o l o g y .  11  THE STUDY AREA The S t r a i t o f G e o r g i a i s a s e m i - e n c l o s e d body o f water open a t b o t h ends t o t h e i n f l u e n c e o f t h e N o r t h P a c i f i c Ocean ( F i g . 1 ) .  The ocean-  ography o f b'oth t h e S t r a i t o f G e o r g i a and t h e a d j a c e n t s u b a r c t i c P a c i f i c has been d e s c r i b e d ( e . g . Doe 1955; P i c k a r d 1956; T u l l y and Dodimead 1957; W a l d i c h u k 1957; Dodimead e t a l . 1963; Dodimead and P i c k a r d I967). The most c o n s p i c u o u s c h a r a c t e r i s t i c o f t h e S t r a i t i s t h e e s t u a r i n e  circula-  t i o n r e s u l t i n g from i n t e r a c t i o n s between incoming o c e a n i c water and o u t g o i n g f r e s h e r water which o r i g i n a t e s i n t h e d r a i n a g e b a s i n s s u r r o u n d i n g the S t r a i t .  A t l e a s t $0% o f t h e f r e s h water e n t e r i n g t h e S t r a i t comes  from t h e b a s i n s d r a i n e d by t h e F r a s e r and Squamish R i v e r s ( H e r l i n v e a u x and Giovando I969).  The i n s i d e passage, which c o n n e c t s t h e n o r t h e r n  end o f t h e S t r a i t o f G e o r g i a w i t h t h e P a c i f i c , i s c h a r a c t e r i z e d by cons t r i c t e d and w i n d i n g waterways. the  The c o n s t r i c t i o n s s u f f i c i e n t l y h i n d e r  t r a n s f e r o f water t h a t t h e c o n t r i b u t i o n o f t h e n o r t h e r n passages t o  t h e l c o m p o s i t i o n o f t h e water i n t h e S t r a i t o f G e o r g i a i s s m a l l compared t o t h e c o n t r i b u t i o n o f t h e S t r a i t o f Juan de F u c a ( W a l d i c h u k 1957; H e r l i n v e a u x and Giovando I969) •  Tbethes:s'o.uth^,stheeGulfiiE&landseahd San  ^uahhArch'ipelago s e p a r a t e t h e main body o f t h e S t r a i t from d i r e c t a c c e s s t o t h e S t r a i t o f Juan de F u c a and hence t h e open ocean. B o t h W a l d i c h u k (1957) and T u l l y and Dodimead (1957) s e p a r a t e d t h e S t r a i t o f Georgia i n t o t h e Southern Approaches, t h e N o r t h e r n Approaches and t h e C e n t r a l S t r a i t ( F i g . 2 ) .  The mechanisms by which water i n t h e  C e n t r a l S t r a i t i s formed have been d i s c u s s e d a t some l e n g t h , by Waldichuk.  particularly  S u r f a c e water ( i . e . water above t h e p r i n c i p a l p y c n o c l i n e )  t e n d s t o be v a r i a b l e , l a r g e l y due t o t i d a l a c t i o n and t h e v a r i a b l e  12a  F i g u r e 1:  D i s t r i b u t i o n of major c u r r e n t s i n t h e o c e a n i c r e g i o n a d j a c e n t t o t h e study a r e a . Currents marked w i t h an a s t e r i s k a r e s e a s o n a l ; s u b s u r f a c e c u r r e n t s a r e i n d i c a t e d by a dashed l i n e . (Based on Dodimead e t a l . I963)  WEST LONGITUDE  13a  F i g u r e 2:  The  study a r e a and  i t s major d i v i s i o n s .  14  e f f e c t o f f r e s h water r u n o f f .  S t r a i t o f G e o r g i a i n t e r m e d i a t e and deep  w a t e r s a r e f a r l e s s v a r i a b l e , and o r i g i n a t e i n t h e S o u t h e r n  Approaches  as a c o m b i n a t i o n o f i n c o m i n g Juan de F u c a i n t e r m e d i a t e and deep water and o u t f l o w i n g s u r f a c e w a t e r .  The S o u t h e r n P a s s a g e s a r e c h a r a c t e r i s t i s  c a l l y w e l l mixed t h r o u g h o u t t h e water column d u r i n g most o f t h e y e a r (Gardner 1972;  Evans 1973).  The c o m p o s i t i o n o f the water e n t e r i n g t h e S o u t h e r n Approaches  from  t h e S t r a i t of Juan de F u c a w i l l v a r y w i t h v a r y i n g o f f s h o r e o c e a n o g r a p h i c conditions.  The major e a s t e r l y c u r r e n t a t t h i s l a t i t u d e i s t h e West  Wind D r i f t ( F i g . 1 ) .  T h i s c u r r e n t d i v e r g e s as i t approaches t h e c o a s t .  One b r a n c h moves n o r t h e r l y towards t h e G u l f o f A l a s k a and t h e o t h e r moves s o u t h e r l y as t h e C a l i f o r n i a C u r r e n t .  A s m a l l p o r t i o n of the water,  however, i n t r u d e s i n t o t h e c o a s t a l w a t e r s o f f Vancouver I s l a n d (Dodimead e t a l . I963).and may  r e s u l t i n t h e movement o f n e a r s u r f a c e water from  the C e n t r a l S u b a r c t i c Domain i n t o Juan de F u c a .  In a d d i t i o n , the p r e -  v a i l i n g summer winds i n t h e e a s t e r n N o r t h P a c i f i c a r e from t h e n o r t h w e s t and blow r o u g h l y p a r a l l e l t o t h e r c o a s t .  A n e t o f f s h o r e movement o f  s u r f a c e water r e s u l t s due t o JFEkman t r a n s p o r t ( e . g . S v e r d r u p e t a l . 1942), and u p w e l l i n g can o c c u r from May t h r o u g h September i n c o a s t a l waters.  The u p w e l l e d water o r i g i n a t e s on t h e c o n t i n e n t a l s h e l f a t  d e p t h s of 200-300 m (Doe 1955)  and r e a d i l y i n t r u d e s i n t o Juan de F u c a .  Water f r o m t h i s d e p t h does n o t n o r m a l l y approach t h e c o a s t (Dodimead e t a l . I963) and u p w e l l i n g i s n e c e s s a r y t o i n t r o d u c e i t in£o i n s h o r e waters. Water o f s o u t h e r n o r i g i n can a l s o r e a c h t h e S t r a i t o f Juan de F u c a . A deep c o u n t e r c u r r e n t ( c a . 200 m) a d j a c e n t t o t h e c o a s t b r i n g s water f r o m  15  t h e e a s t e r n boundary r e g i o n o f t h e s u b t r o p i c s t o t h e west c o a s t o f B r i t i s h Columbia (Dodimead  e t a l . 1963)-  The e x t e n t o f t h i s  "Califor-  n i a U n d e r c u r r e n t Domain" v a r i e s s e a s o n a l l y and a n n u a l l y and t h u s has a f l u c t u a t i n g e f f e c t on t h e S t r a i t of Juan de F u c a .  During the upwelling  season, t h e n o r t h w a r d f l o w o c c u r s o n l y a t d e p t h s o f 200 m o r g r e a t e r ( S v e r d r u p and F l e m i n g 1941).  When u p w e l l i n g c e a s e s , a s u r f a c e c o u n t e r -  c u r r e n t , t h e D a v i d s o n C u r r e n t , d e v e l o p s as w e l l , r e s u l t i n g i n n o r t h e r l y f l o w a l o n g t h e c o a s t a t a l l d e p t h s ( S v e r d r u p e t a l . 1942).  In these  c o n d i t i o n s , water o r i g i n a t i n g i n t h e C o l u m b i a R i v e r system can r e a d i l y be c a r r i e d n o r t h and i n t o Juan de F u c a .  At other times of the year,  t h e r e i s s t i l l a d i s t i n c t n o r t h w a r d f l o w n e a r t h e s e a bed between t h e mouth o f t h e Columbia R i v e r and t h e S t r a i t o f Juan de F u c a ( B a r n e s e t al.  1972).  Whatever t h e o r i g i n s of t h e water e n t e r i n g Juan de F u c a , t h e  complex  i n t e r a c t i o n between o c e a n i c water and f r e s h w a t e r i n t h e S o u t h e r n App r o a c h e s r e s u l t s i n a f i n e l y b a l a n c e d system.  I n c r e a s e d r u n o f f , which  •would have a d i l u t i n g e f f e c t , o c c u r s a t t i m e s o f i n c r e a s e d i n p u t o f h i g h e r s a l i n i t y o c e a n i c w a t e r and v i c e - v e r s a .  Hence, t h e s a l i n i t y o f  t h e S t r a i t of G e o r g i a bottom water does n o t v a r y g r e a t l y from y e a r t o y e a r , a l t h o u g h o t h e r c h e m i c a l c h a r a c t e r i s t i c s o f t h e water may v a r y more m a r k e d l y due t o d i f f e r e n c e s i n t h e makeup o f t h e i n c o m i n g o c e a n i c water and o f t h e f r e s h water r u n o f f .  Water moves i n t o t h e S t r a i t a t i n t e r -  mediate d e p t h s f o r much o f t h e y e a r , ( H e r l i n v e a u x and Giovando  I969),  b u t i n t h e l a t e summer and f a l l t h e i n t r u d i n g water i s s u f f i c i e n t l y dense t o r e p l a c e t h e deep water i n t h e S t r a i t o f G e o r g i a ( W a l d i c h u k 1957; Gardner  1972).  16  Once i n the S t r a i t of Georgia, the intruding water mixes slowly with the water i t displaced.  The bottom topography of the Central S t r a i t i s  r e l a t i v e l y smooth, and other than the boundaries of the main basin there are few s t r u c t u r a l b a r r i e r s to l a t e r a l mixing processes.  The r e s u l t i s  a large deep water mass i n the Central S t r a i t overlain by a much more variable but r e l a t i v e l y t h i n surface layer.  There are no currently  documented physical or chemical processes within the Central S t r a i t that might lead to large-scale permanent horizontal heterogeneity of-the zooplankton community found there.  17  DESCRIPTION AND. ANALYSIS OF STRAIT OF GEORGIA ZOOPLANKTON Introduction There axe many d i f f i c u l t i e s i n a d e q u a t e l y s a m p l i n g p o p u l a t i o n s d i s p e r s e d i n a t h r e e - d i m e n s i o n a l medium.  Z o o p l a n k t o n t e n d t o be d i s t r i b u t e d  i n p a t c h e s r a t h e r than c o n t i n u o u s l y ( C u s h i n g I 9 6 I ) .  Since the s i z e  and  shape o f t h e p a t c h e s p r o b a b l y v a r i e s , r e p l i c a t e n e t h a u l s t a k e n i n t h e same a r e a can be q u i t e d i f f e r e n t (Barnes 194-9; B a r n e s and M a r s h a l l H o p k i n s I963; Wiebe and H o l l a n d 1968; of  Wiebe 1970) .  zooplankton patfaheseareapoorly understood.  The  characteristics  Wiebe's d a t a  (^^O^^ug  g e s t t h a t t h e y a r e a p p r o x i m a t e l y c i r c u l a r w i t h a r a d i u s o f about meters,  and a r e d i s t r i b u t e d randomly.  1951;  Denman and P i a t t (1975)1  -  fifty on t h e  o t h e r hand, f e e l t h a t p h y t o p l a n k t o n p a t c h e s a r i s i n g from p h y s i c a l t r a n s p o r t p r o c e s s e s range from about f i f t y meters size.  -  to several kilometers i n  U n t i l our u n d e r s t a n d i n g o f t h e mechanisms and c h a r a c t e r i s t i c s o f  p l a n k t o n p a t c h i n e s s i s more d e t a i l e d , p a t c h i n e s s w i l l remain a source o f e r r o r t h a t can n e i t h e r be f u l l y e v a l u a t e d o r compensated f o r . I n c o r r e c t c h o i c e o f s a m p l i n g g e a r can a l s o l e a d t o e r r o r .  Varia-  t i o n i n s a m p l i n g e f f i c i e n c y of d i f f e r e n t z o o p l a n k t o n s a m p l i n g d e v i c e s i s l a r g e , and y e t t h e r e a r e no u n i v e r s a l l y a c c e p t e d s t a n d a r d d e s i g n s f o r such n e t s .  The f a c t o r s which must be c o n s i d e r e d i n d e s i g n i n g an adequate  n e t have, however, been i n v e s t i g a t e d ( e . g . T r a n t e r and F r a s e r I968; N a t i o n a l Academy o f S c i e n c e I969) • a r e n e t s i z e and mesh s i z e .  The two most i m p o r t a n t v a r i a b l e s  Wiebe and H o l l a n d (1968) suggest t h a t on a  t h e o r e t i c a l b a s i s l a r g e r n e t s sample more e f f i c i e n t l y and w i t h l e s s e r r o r than s m a l l e r n e t s .  V e r y l a r g e n e t s , however, can be awkward and  diffi-  c u l t t o h a n d l e a t sea, and a b a l a n c e must be a c h i e v e d between c a t c h i n g  18  e f f i c i e n c y and h a n d l i n g  characteristics.  The c h o i c e o f optimum mesh s i z e a l s o r e q u i r e s a compromise.  The  mesh a p e r t u r e s h o u l d be s m a l l enough t o c a p t u r e a l l o f t h e organisms t o be sampled.  However, as the mesh a p e r t u r e d e c r e a s e s ,  t h e r i s k of c l o g -  g i n g o f t h e meshes and subsequent r e j e c t i o n o f water i n c r e a s e s . two f a c t o r s must a l s o be b a l a n c e d zooplankton.  These  when d e s i g n i n g equipment f o r sampling  19  Sample C o l l e c t i o n and Analysis Introduction The zooplankton analyses presented here are based on samples taken at Geo 1748, a station approximately. 14.-.-5 km •-east of Nanaimo, . B r i t i s h Columbia (-Fig. 2).  Geo 1748,. .with a bottom depth of .420 m,.- i s i n  one..of the deepest parts of the ..Strait of .Georgia.  Based on previous  records (Stephens et a l . 1969; Gardner 1972; Evans 1973). i f i s reasonable to consider the zooplankton found at t h i s station as t y p i c a l of open water S t r a i t of Georgia zooplankton. the Institute of Oceanography, University  The station was monitored by of B r i t i s h Columbia,  on an a l -  most continuous monthly basis from October 1969 to December 1974, and thus samples from a f i v e year period were available.  Procedure Two types of sample were collected; s t r a t i f i e d tows taken at twelve depths (10, 30, 50, 75, 100, 150, 200, 250, 300, 350, 375, 390 m) with modified Clarke-Bumpus opening/closing samplers (Paquette and Frolander 1957), and v e r t i c a l hauls taken from 390 m to the surface with a conical net having a seventy centimeter mouth diameter.  The s t r a t i f i e d  tows were discontinued a f t e r June 197*+> but the v e r t i c a l hauls were available f o r the entire sampling period. Concurrent hydrographic data were collected i n each month from standard depths (0, 10, 20, 30, 50, 75, 100, 150, 200, 250, 300, 350, 375, 390 m).  Hydrographic data could not be taken with the December 1972  b i o l o g i c a l data because of time restrictions!;; however, hydrographic data from November 1972 were used as the best approximation of the  20  m i s s i n g December d a t a .  Temperature i n s i t u ' w a s measured u s i n g r e v e r -  s i n g thermometers, and a water sample was taken from each depth f o r s a l i n i t y determination.  S u r f a c e d a t a were taken from a bucket sample  u s i n g a s t a n d a r d s a l i n i t y sample b o t t l e and an o r d i n a r y thermometer graduated  i n 0.1 G° i n c r e m e n t s .  D e n s i t y v a l u e s , expressed as sigma-t,  were then c a l c u l a t e d f o r each depth a c c o r d i n g t o s t a n d a r d nomographs p r e p a r e d by t h e U.S. Navy H y d r o g r a p h i c O f f i c e (H.O. M i s c . 1504-7, Nos. 3-8). Each v e r t i c a l h a u l sample was p l a c e d i n a s i x t e e n ounce g l a s s j a r and i m m e d i a t e l y p r e s e r v e d by t h e a d d i t i o n o f s u f f i c i e n t n e u t r a l b u f f e r e d f o r m a l i n t o make up an approximate 1976).  5% ( v o l / v o l ) s o l u t i o n ( e . g . Steedman  The Glarke-Bumpus samples were t r e a t e d s i m i l a r l y (see Gardner  1972; Evans 1973)'  I n a n a l y s i n g t h e b i o l o g i c a l m a t e r i a l , emphasis was  p l a c e d on v e r t i c a l h a u l samples t a k e n i n e a r l y w i n t e r (October t o Decemb e r ) . D u r i n g t h e s e months, l e s s s h o r t - t e r m f l u c t u a t i o n o c c u r s i n t h e z o o p l a n k t o n p o p u l a t i o n than a t any o t h e r t i m e o f t h e y e a r , and t h e p o s s i b i l i t y o f t h e masking o f y e a r t o y e a r v a r i a t i o n by s e a s o n a l v a r i a t i o n i s minimized. I n t h e l a b o r a t o r y , each v e r t i c a l h a u l sample was p l a c e d i n a s o r t i n g t r a y , and a l l l a r g e organisms ;(?eirg. E u p h a u s i i d s , l a r g e Tomopteris, l a r g e amphipods,...) were removed.  The r e m a i n i n g m a t e r i a l was p l a c e d  i n a p l a n k t o n s p l i t t e r and s p l i t i n t o two e q u a l p o r t i o n s , one o f which was d i s c a r d e d .  Any conspicuous  s p e c i e s t h a t were p r e s e n t i n s m a l l  enough numbers t o be c o m p l e t e l y removed were s o r t e d from t h e r e m a i n i n g half.  T h i s h a l f was f u r t h e r s p l i t u s i n g a m o d i f i e d F o l s o m P l a n k t o n  S p l i t t e r (Gardner 1972), and t h e s u b s a m p l i n g / s o r t i n g p r o c e s s was  21  continued  u n t i l s o r t i n g was complete.  W i t h few e x c e p t i o n s , were s o r t e d .  o n l y a d u l t and i m m e d i a t e l y p r e - a d u l t  F l u c t u a t i o n s i n the s i z e of successive generations  stages of a  s p e c i e s w i l l be r e l a t e d t o t h e number o f s e x u a l l y mature i n d i v i d u a l s produced w i t h i n each g e n e r a t i o n . stage, estimates  As t h e a d u l t i s o f t e n a s h o r t - l i v e d  o f t h e b r e e d i n g p o p u l a t i o n t h a t a r e based on t h e num-  ber o f i n d i v i d u a l s i n the stage immediately preceding  t h e a d u l t w i l l be  more p r e c i s e than e s t i m a t e s based s o l e l y on t h e number o f a d u l t s captured.  When i d e n t i f i c a t i o n was p.ossible, young s t a g e s  were a l s o s o r t e d ,  o f major s p e c i e s  Some s p e c i e s were combined i n t o groups f o r conven-  i e n c e ; however, i t h a s been shown ( W i l l i a m s o n 19^1; B a i n b r i d g e and F o r s y t h 1972) t h a t t h e m i x t u r e  o f s p e c i e s d a t a w i t h group d a t a  should  not d e t r a c t f r o m t h e d a t a a n a l y s i s .  In other species, e s p e c i a l l y i n  non-copepod groups, i t was d i f f i c u l t  to differentiate later l i f e history  stages.  I n t h e s e cases, a l l s t a g e s t h a t were n o t o b v i o u s l y j u v e n i l e  were s o r t e d and counted a s a u n i t . The  Glarke-Bumpus samples were s o r t e d t o e s t a b l i s h t h e v e r t i c a l  d i s t r i b u t i o n o f C a l a n u s plumchrus and C a l a n u s m a r s h a l l a e ,  and t o o b t a i n  t h e d e p t h d i s t r i b u t i o n o f each s p e c i e s s o r t e d i n t h e v e r t i c a l h a u l s . Two months, November and J a n u a r y 1973, were chosen a t random and s o r t e d for  t h e two C a l a n u s s p e c i e s o n l y .  for  complete s o r t i n g .  November and December 1971 were chosen  I n t h e l a t t e r case, s e l e c t i n g two c o n t i g u o u s  months r e d u c e s e r r o r due t o a n n u a l f l u c t u a t i o n .  I n a d d i t i o n , i n Novem-  b e r 1971 t h e h o r i z o n t a l tows were t a k e n between 1700 and 1800hr, e a r l i e r than i n any o t h e r w i n t e r month. m i d n i g h t and 0200hr.  I n December, t h e t o w s were 'taken-'between :  November 1971 was s e l e c t e d i n t e n t i o n a l l y t o g e t a s  22  c l o s e as p o s s i b l e t o the pre-migration v e r t i c a l d i s t r i b u t i o n of species with a d i e l migration pattern. mean p o s i t i o n  When averaged w i t h t h e December d a t a , a  f o r each s p e c i e s w i t h i n t h e water column was g e n e r a t e d .  F o r v e r t i c a l l y m i g r a t i n g s p e c i e s t h i s meant t h a t t h e average calculated  position  i n c l u d e d s p e c i f i c d a t a from b o t h t h e n i g h t d i s t r i b u t i o n and  the l a t e afternoon d i s t r i b u t i o n , j u s t a f t e r  sunset.  E v a l u a t i o n o f sampling gear The mesh a p e r t u r e o f b o t h t y p e s o f n e t was 350 ym.  This i s  l a r g e r than t h e 200 urn a p e r t u r e s i z e recommended by UNESCO f o r c a p t u r i n g s m a l l e r mesozooplankton ( T r a n t e r and F r a s e r 1968), b u t c o r r e s p o n d s c l o s e l y t o t h e 333 urn a p e r t u r e recommended by t h e N a t i o n a l Academy o f Sciences  (I969) a s t h e s m a l l e s t mesh r e t a i n i n g  f o r t h e d u r a t i o n o f a f i f t e e n minute tow. spectrum o f z o o p l a n k t o n ,  including  stages o f n u m e r i c a l l y important  its filtering  efficiency  B o t h n e t s c a p t u r e a wide s i z e -  l a r g e numbers o f t h e e a r l y  copepodite  copepod s p e c i e s (e.g. Gardner 1972;  Evans  1973)• Neither design of net i s i d e a l .  P e r h a p s t h e major o b j e c t i o n t o t h e  use o f t h e Clarke-Bumpus sampler i s t h a t i t s s m a l l s i z e , and t h e mechanic a l c l u t t e r i n and around t h e mouth, f a c i l i t a t e a v o i d a n c e o f t h e sampler by t h e more m o b i l e s p e c i e s .  Such a v o i d a n c e may r e s u l t i n a b i a s e d sam-  p l e , w i t h t h e degree o f b i a s f l u c t u a t i n g s i z e (Regan I963). zooplankton  w i t h b o t h < towing speed and mesh  These problems p r i m a r i l y  population sizes.  t  affect the estimation of  The Clarke-Bumpus sampler i s , however,  one o f t h e b e s t s a m p l e r s a v a i l a b l e  f o restimating the v e r t i c a l d i s t r i -  b u t i o n o f a s p e c i e s , a s i t i s one o f t h e few p l a n k t o n samplers t h a t  23  a l l o w s t h e t a k i n g o f d i s c r e t e ' s t r a t i f i e d h a u l s (McHardy The  s e v e n t y c e n t i m e t e r n e t used i n t h e c o l l e c t i o n o f t h e v e r t i c a l  h a u l s approximates F r a s e r (I968).  t h e p r e f e r r e d s p e c i f i c a t i o n s o u t l i n e d by T r a n t e r  and  I t s major weakness appears t o be a s e n s i t i v i t y t o t h e  patchiness i n plankton d i s t r i b u t i o n s .  The Glarke-Bumpus  s i n c e i t i s towed h o r i z o n t a l l y f o r about 0.5 the e f f e c t s o f s m a l l - s c a l e p a t c h e s  km,  F o r my  sampler,  t e n d s t o average out  ( G i l f i l l a n I967).  u s u a l l y has a much s h o r t e r p a t h l e n g t h and may patch.  1961).  o r may  The v e r t i c a l h a u l not t r a n s e c t a  samples, I assume t h a t t h e v e r t i c a l h a u l g i v e s s a n a c c u -  r a t e estimate of the r e l a t i v e p r o p o r t i o n s of the v a r i o u s s p e c i e s t h a t i t captures.  T h i s assumption  i s s u p p o r t e d by t h e r e l a t i v e l y l o n g p a t h  l e n g t h o f t h e v e r t i c a l tow (390 m),  and by t h e f a c t t h a t t h e deep w a t e r  i n t h e a r e a i s h o r i z o n t a l l y w e l l mixed.  G i l f i l l a n (I967) a l s o s u g g e s t s  t h a t t h e s e v e n t y c e n t i m e t e r n e t g i v e s a r e p r e s e n t a t i v e sample o f t h e z o o p l a n k t o n , a l t h o u g h he recommends a h i g h e r t o w i n g speed t h a n i s n o r mally f e a s i b l e .  24  S t a t i s t i c a l Methodology Introduction The raw d a t a c o n s i s t e d o f a t i m e s e r i e s o f c o n c e n t r a t i o n v a l u e s f o r each o f a number o f s p e c i e s .  A n a l y s i n g any such f a m i l y o f  c o n t i n u o u s v a r i a b l e s a s a u n i t , r a t h e r than i n d i v i d u a l l y , r e q u i r e s t h e use o f some form o f m u l t i v a r i a t e a n a l y s i s .  In ecological research,  m u l t i v a r i a t e t e c h n i q u e s have been a p p l i e d p r i m a r i l y i n two s e p a r a t e a r e a s : n u m e r i c a l taxonomy ( e . g . S o k a l and M i c h e n e r 1958; R o h l f and S o k a l 1962;  S o k a l and S n e a t h I963; W a l l a c e and Bader I967), and t h e a n a l y s i s  o f community s t r u c t u r e i n p l a n t s and r e l a t i v e l y s e d e n t a r y a n i m a l s ( e . g . G o o d a l l 1954; C a s s i e and M i c h a e l I968; L i e and K e l l y 1970; Dayyet a l . 1971;  L i n d s t r o m 1974). T y p i c a l l y , t h e d a t a f o r community a n a l y s e s a r e o b t a i n e d from a  t r a n s e c t a l o n g which t h e r e i s some g r a d a t i o n i n an e n v i r o n m e n t a l meter.  The d a t a a r e o f t e n t a k e n from a s e r i e s o f q u a d r a t s o f s t a n d a r d  s i z e p l a c e d a t random a l o n g t h e t r a n s e c t l i n e . tively  para-  Each q u a d r a t i s exhaus-  counted t o produce c o n c e n t r a t i o n v a l u e s f o r each o f t h e s p e c i e s  found i n i t , and t h e r e s u l t s a r e combined t o form a m a t r i x o f s p e c i e s data.  Each s p e c i e s i s t h u s r e p r e s e n t e d by a s e r i e s o f c o n c e n t r a t i o n  values corresponding t o i t s c o n c e n t r a t i o n i n successive quadrats ( e . g . L i n d s t r o m 197^) •  The d a t a i n my p r o j e c t d i f f e r from t h i s form o n l y i n  t h a t t h e c o n c e n t r a t i o n values a r e arrayed along a temporal r a t h e r than a spatial axis.  T h i s d i f f e r e n c e w i l l n o t a f f e c t t h e use o f m u l t i v a r i a t e  a n a l y s i s , and may s i m p l i f y t h e i n t e r p r e t a t i o n o f some o f t h e t e c h n i q u e s used, s i n c e t h e a x i s a l o n g w h i c h t h e d a t a a r e a r r a y e d i s more r e g u l a r . P r e v i o u s m u l t i v a r i a t e a n a l y s e s o f z o o p l a n k t o n d a t a have tended t o  25  be r e s t r i c t e d i n both scope and number.  Williamson  (1961, I963) a n a l y s e d  p l a n k t o n r e c o r d s i n t h e N o r t h Sea by both p r i n c i p a l components and mult i p l e correlation analyses. v a l u e s f o r twenty-three  H i s d a t a c o n s i s t e d o f average  abundance  s p e c i e s over t e n y e a r s , and were r e s t r i c t e d t o  June, J u l y and p a r t o f August, d u r i n g t h e h e r r i n g season. showed a s i g n i f i c a n t r e l a t i o n s h i p between t h e zooplankton which W i l l i a m s o n attempted  The a n a l y s e s and t h e h e r r i n g  t o i n t e r p r e t on a b i o l o g i c a l b a s i s .  Angel and  Fasham (1973» 197*+) have made e x t e n s i v e use o f f a c t o r a n a l y s i s and p r i n c i p a l components a n a l y s i s t o examine t h e d a t a from t h e SOND C r u i s e o f I965, i n an e f f o r t t o s e p a r a t e s p e c i e s groups by v e r t i c a l d i s t r i b u t i o n p a t t e r n and water mass r e l a t i o n s h i p s . day  The SOND d a t a c o n s i s t e d o f one d  s e r i e s and one n i g h t s e r i e s o f v e r t i c a l h a u l s c o v e r i n g 19 depth  ranges,  and a s i m i l a r s e t o f h o r i z o n t a l tows taken with an I s a a c s -  K i d d Midwater T r a w l .  I n a n a l y s i n g t h e v e r t i c a l h a u l d a t a , A n g e l and  Fasham were d e a l i n g with a maximum o f 38 samples and i n cases where o n l y n i g h t o r day d a t a were c o n s i d e r e d , w i t h a maximum of 19 samples. More r e c e n t l y , A n g e l and Fasham (1975) and Fasham and A n g e l  (1975)  have used f a c t o r a n a l y s i s and c l u s t e r a n a l y s i s t o examine t h e d i s t r i b u t i o n and water mass r e l a t i o n s h i p s o f p l a n k t o n i c o s t r a c o d s i n t h e n o r t h e a s t A t l a n t i c Ocean.  They examined d a t a from s i x s t a t i o n s , each o f  which was sampled a t 16 d e p t h h o r i z o n s once d u r i n g t h e day and once d>-r d u r i n g the n i g h t .  The s t a t i o n s were a n a l y s e d i n d e p e n d e n t l y ,  making t h e  e f f e c t i v e d a t a base f o r each a n a l y s i s a s e t o f 32 samples. L o c a l l y , Marlowe and M i l l e r (1975) have used n e s t e d f a c t o r t o examine t h e zooplankton the s u b a r c t i c P a c i f i c .  analysis  community a t ocean weather s t a t i o n "Papa" i n  They c o l l e c t e d t h e i r d a t a i n a v e r y r e s t r i c t e d  26  t i m e p e r i o d , however, and a n a l y s e d b i o l o g i c a l d a t a o n l y .  Their data  base c o n s i s t e d o f 36 samples (two day s t a t i o n s and two n i g h t s t a t i o n s sampled a t n i n e d e p t h s e a c h ) . These and s i m i l a r a n a l y s e s g e n e r a l l y c o n s i d e r o n l y one o r two m u l t i v a r i a t e techniques.  In a d d i t i o n , w i t h the exception of Williamson  (1961, I963) t h e y a r e a l l of a g e o g r a p h i c r a t h e r than a t e m p o r a l n a t u r e . F o r my a n a l y s e s , i n f o r m a t i o n has been o b t a i n e d w i t h s i x d i f f e r e n t  sta-  t i s t i c a l techniques: m u l t i p l e c o r r e l a t i o n , c l u s t e r a n a l y s i s , p r i n c i p a l components a n a l y s i s , c a n o n i c a l c o r r e l a t i o n , f a c t o r a n a l y s i s and m u l t i p l e regression. data.  D i v e r s i t y i n d i c e s have a l s o been c a l c u l a t e d f o r a l l o f t h e  These t e c h n i q u e s w i l l be e v a l u a t e d i n a l a t e r s e c t i o n .  Data treatment S a l i n i t y and temperature 10,  50, 200, 300,and 350 m.  v a l u e s were chosen from f i v e  S t a b i l i t y v a l u e s e x p r e s s e d as  depths:  ^depthy^  were c a l c u l a t e d over f i v e d e p t h r a n g e s : 0-10, 10-50, 50-200, 200-300 and 300-350 m.  U s i n g more than t h e s e f i v e s u b d i v i s i o n s of each p a r a -  meter i s e x p e n s i v e and c o m p l i c a t e d .  As w i l l be shown i n t h e r e s u l t s  s e c t i o n , t h e s u b d i v i s i o n s chosen a d e q u a t e l y r e p r e s e n t t h e f u l l range o f the three hydrographic  parameters.  The scope o f t h e b i o l o g i c a l d a t a was such t h a t i t was n e c e s s a r y t o reduce t h e d a t a b l o c k t o a more manageable s i z e .  D a t a were o r i g i n a l l y  r e c o r d e d as t h e number o f organisms of each s p e c i e s p e r c u b i c meter, e i t h e r i n t e g r a t e d over t h e whole water column ( v e r t i c a l n e t h a u l ) o r for  a s p e c i f i c d e p t h range ( h o r i z o n t a l tow).  This o r i g i n a l data i n c l u -  ded c o n c e n t r a t i o n v a l u e s f o r many s p e c i e s which were p r e s e n t i n v e r y  27  low numbers. sampling,  Because o f t h e v a r i a b i l i t y i n h e r e n t i n z o o p l a n k t o n  c o n c e n t r a t i o n s o f l e s s than about 0.05 p e r c u b i c meter a r e  d i f f i c u l t to discriminate.  I n such c a s e s , t h e a p p a r e n t absence o f t h e  s p e c i e s from a sample i s v i r t u a l l y m e a n i n g l e s s .  I t may be p r e s e n t  i na  c o n c e n t r a t i o n o n l y s l i g h t l y below n o r m a l , b u t l o w enough t o be i n d e t e c table.  Thus t h e v a r i a t i o n i n d u c e d by t h e s a m p l i n g  g e a r masks t h e n a t u r a l  v a r i a t i o n i n t h e p o p u l a t i o n s i z e s o f uncommon s p e c i e s . the o r i g i n a l d a t a b l o c k were p r e s e n t  Other s p e c i e s i n  i n a p p r e c i a b l e numbers, b u t ap-  p e a r e d i n o n l y a f e w samples, a d d i n g e x c e s s i v e l y t o t h e v a r i a b i l i t y o f the d a t a .  To r e d u c e d a t a v a r i a b i l i t y from t h e above s o u r c e s ,  which were p r e s e n t  species  i n c o n c e n t r a t i o n s o f l e s s than 0.05 p e r c u b i c meter  and/or i n l e s s t h a n 50$ o f t h e samples were dropped f r o m t h e a n a l y s i s . These c r i t e r i a a r e s i m i l a r t o t h o s e o f Marlowe and M i l l e r eliminated species present  (1975) who  i n l e s s t h a n t h r e e samples and/or i n concen-  t r a t i o n s l e s s t h a n 0.05 p e r c u b i c meter. A f t e r t h e b a s i c d a t a m a t r i x was c o n s t r u c t e d , d a t a from t h e two s e t s of h o r i z o n t a l tows were used t o c a l c u l a t e t h e average p r o p o r t i o n o f t h e p o p u l a t i o n o f each s p e c i e s i n each o f t h e t h r e e t y p e s o f water r e c o g n i z a b l e a t Geo 17*4-8.  These w a t e r t y p e s a r e : n e a r s u r f a c e (0-75 m),  i n t e r m e d i a t e (75-200 m) and deep (200-390 m) (Gardner 1972).  The t o t a l  c o n c e n t r a t i o n o f a s p e c i e s a s c a l c u l a t e d f r o m each v e r t i c a l h a u l was s p l i t i n t o t h r e e components based on t h e c a l c u l a t e d p r o p o r t i o n s . Similarly., s p l i t t i n g ^ a l l l s p e c i e s sisting  S  y i e l d e d a p a r t i t i o n e d d a t a m a t r i x con-  o f t h e c o n c e n t r a t i o n o f each s p e c i e s i n each o f t h e t h r e e  regions  o f t h e water column over t h e t i m e p e r i o d f o r which d a t a were a v a i l a b l e . Some o f t h e s t a t i s t i c a l methods used ( e . g . c o r r e l a t i o n and r e g r e s s i o n )  28  contain the i m p l i c i t mally d i s t r i b u t e d .  assumption  t h a t the d a t a being analysed are nor-  D e v i a t i o n s from n o r m a l i t y may  be c o r r e c t e d f o r by  a p p l y i n g a n o r m a l i z i n g f u n c t i o n t o the data block p r i o r to the analyses (e.g.  B a r n e s 1952;  W i l l i a m s o n 1963;  G a s s i e and M i c h a e l I968).  My b a s i c  d a t a m a t r i x was t r a n s f o r m e d u s i n g t h e f u n c t i o n : x' = l n ( x + 0.01). L o g a r i t h m i c t r a n s f o r m a t i o n s have been used p r e v i o u s l y w i t h s i m i l a r d a t a (e.g.  W i l l i a m s o n I963: x  M i c h a e l I968: x t i o n was  1  1  = l o g ( x ) ; Hughes e t a l . 1972,  = I n ( x + 1.0)).  e v a l u a t e d by examining  Gassie  and  The e f f e c t i v e n e s s o f t h e t r a n s f o r m a skewness and k u r t o s i s , b e f o r e and  after  t r e a t m e n t , o f two s p e c i e s and two months chosen a t random from t h e d a t a bank. F o r some a n a l y s e s , i t was the intrasample v a r i a b i l i t y species being considered.  an advantage t o f u r t h e r reduce  either  o f t h e z o o p l a n k t o n d a t a o r t h e number o f I n t h e s e c a s e s , s p e c i e s which had b a r e l y met  t h e c r i t e r i a f o r b e i n g i n c l u d e d i n t h e b a s i c z o o p l a n k t o n m a t r i x were also eliminated. The d a t a m a n i p u l a t i o n y i e l d e d e i g h t m a t r i c e s : t h e m a t r i x o f each h y d r o g r a p h i c v a r i a b l e v e r s u s month, t h e b a s i c z o o p l a n k t o n s p e c i e s conc e n t r a t i o n v e r s u s month m a t r i x , the p a r t i t i o n e d and/or t r a n s f o r m e d v e r s i o n s of the b a s i c m a t r i x and t h e t r a n s f o r m e d and p a r t i t i o n e d c o r e s p e c i e s matrix.  Statistical  procedures  U n l e s s o t h e r w i s e n o t e d , t h e s t a t i s t i c a l a n a l y s e s were  performed  v i a l i b r a r y programmes a v a i l a b l e on t h e IBM 370/168 system m a i n t a i n e d t h e Computing C e n t r e o f t h e U n i v e r s i t y o f B r i t i s h Columbia.  by  The r e f e r e n c e  29  name f o r each UBG  programme i s g i v e n i n t h e t e x t when the programme i s  f i r s t mentioned.  I n i t i a l l y , v a r i o u s s t a n d a r d measures o f d i v e r s i t y  ( T a b l e I ) were c a l c u l a t e d from t h e raw d a t a p r i o r t o r e d u c t i o n o f t h e  T a b l e I : D i v e r s i t y i n d i c e s and t h e i r methods o f c a l c u l a t i o n . ( v a r i o u s s o u r c e s ; summarized i n P a r s o n s and T a k a h a s h i 1973)  H  = IT  l o  «2  n^n^L.-n.!  H  H * -H' R (redundancy) = „, * . max min  H  max  •  -|i^° 2 S  H  max  i s t h e v a l u e whxch H x  =  E (evenness) =  m a  where:  '  -i  would have x f a l l s p e c i e s were -U  p r e s e n t i n e q u a l numbers H'.' ' i s t h e v a l u e which H would have i f mm , were p r e s e n t n. i s t h e number o f s p e c i e s ' i ' i n t h e p?" i s the p r o p o r t i o n of s p e c i e s ' i ' i n N i s t h e t o t a l number o f organisms i n H i s defined analogously to H max max  o n l y one  species  sample the sample t h e sample  1  i n i t i a l species l i s t .  An i n i t i a l m u l t i p l e c o r r e l a t i o n (UBC  *C0RN)  was  then c a r r i e d out on t h e t r a n s f o r m e d b a s i c z o o p l a n k t o n s p e c i e s d a t a . The  i n t e n t o f t h e s e i n i t i a l m a n i p u l a t i o n s was  t o get a p r e l i m i n a r y '  e s t i m a t e of t h e degree and t y p e s o f i n t e r a c t i o n s o c c u r r i n g between t h e s p e c i e s , and t o l o o k f o r i n d i c a t i o n s o f a change i n d i v e r s i t y , a b a s i c community parameter.  F o r t h e c o r r e l a t i o n a n a l y s i s , and f o r a l l o t h e r  s t a t i s t i c a l programmes, t h e 1Q% p r o b a b i l i t y l e v e l i s used as t h e t e r i o n f o r r e j e c t i o n o f t h e n u l l h y p o t h e s i s (H ) .  cri-  30  The r e m a i n i n g a n a l y s e s were s e l e c t e d  to investigate  t h e r e l a t i o n s h i p s between groups o f z o o p l a n k t o n  s p e c i e s and t h e r e l a -  t i o n s h i p o f t h e s e groups t o h y d r o g r a p h i c p a r a m e t e r s . d a t a m a t r i x was  clustered  i n more d e t a i l  The  partitioned  u s i n g a c l u s t e r a n a l y s i s programme p r e p a r e d  by Mr. E r i c Minch f o r Dr. R.E.  Foreman, Department of Botany, UBC.  c l u s t e r i n g o f s p e c i e s and c l u s t e r i n g o f samples were c a r r i e d  out.  To examine r e l a t i o n s h i p s between t h e h y d r o g r a p h i c d a t a and b i o l o g i c a l d a t a , c a n o n i c a l c o r r e l a t i o n s were c a l c u l a t e d t ( w i t h 06M)  Both  the  UBC  BMD  w i t h t h e b i o l o g i c a l and p h y s i c a l d a t a b l o c k s i n phase and t h r e e  s i x months out of phase.  Hydrographic  and  d a t a f o r t h e s e comparisons were  o b t a i n e d e i t h e r from I n s t i t u t e o f Oceanography d a t a r e p o r t s (1970-1975)', o r from o r i g i n a l d a t a .  F o r t h e c a n o n i c a l c o r r e l a t i o n s , t h e s p e c i e s were  grouped a c c o r d i n g t o t h e i r p o s i t i o n i n t h e w a t e r column.  C a l a n u s plum-  chrus and C_. m a r s h a l l a e were r u n as s i n g l e s p e c i e s 'groups' i n a d d i t i o n t o b e i n g r u n w i t h i n t h e i r own  groupings.  Chi-square  significance  values  f o r the c a n o n i c a l c o r r e l a t i o n c o e f f i c i e n t s were c a l c u l a t e d by hand f r o m t h e Lambda s t a t i s t i c u s i n g B a r t l e t t ' s t e s t ( C o o l e y and Lohnes 1971)• Each s p e c i e s i n t h e c o r e d a t a s p e c i e s m a t r i x was r e g r e s s e d ( u s i n g UBC  *STRP) a g a i n s t each h y d r o g r a p h i c v a r i a b l e i n t h e same phase r e l a -  t i o n s h i p s as f o r t h e c a n o n i c a l c o r r e l a t i o n s .  Because o f t h e h i g h d e g r e e  o f i n t e r s p e c i f i c c o r r e l a t i o n among t h e amphipods, S c i n a b o r e a l i s added t o t h e core s p e c i e s m a t r i x f o r t h i s a n a l y s i s . o f each h y d r o g r a p h i c  v a r i a b l e were t r e a t e d  was  The s u b d i v i s i o n s  as a s e r i e s o f f i v e i n d e -  pendent v a r i a b l e s a g a i n s t which t h e dependent v a r i a b l e , l n ( 0 . 0 1 + number of s p e c i e s 'A' p e r m ), was r e g r e s s e d .  Only t h o s e independent  variables  which were s i g n i f i c a n t were i n c l u d e d i n t h e f i n a l r e g r e s s i o n e q u a t i o n .  31  Significance was defined as having F  ^ '< 0.10,  where F i s the r a t i o of  the mean square due to regression to the deviations mean square, and F\prob i s the p r o b a b i l i t y of having an equivalent or higher value of F. To examine redundancy and natural grouping within the zooplankton species, a f a c t o r analysis (UBG *FAN) of the partitioned, transformed data was carried out.  The largest grouping generated i n t h i s analysis  was refactored as a separate unityto increase the d e f i n i t i o n of the factors. P r i n c i p a l components analysis (UBG BMD 01M) of both the winter hydrographic data and the core species b i o l o g i c a l data were carried out to gain further information on the degree of redundancy i n the data, and on the most i n f l u e n t i a l components of the community.  Evaluation of techniques The use of sophisticated multivariate techniques f o r the o r d i nation and analysis of community data has expanded greatly i n the past twenty-five years, l a r g e l y due to the increased e f f i c i e n c y and a v a i l a b i l i t y of d i g i t a l computers.  The a b i l i t y to handle complex sets of data  has generated a large number of c o n f l i c t i n g methods, many of which have been argued against as often as they have been supported (e.g. Beals 1973; Whittaker 1973; Lindstrom 197*+) • Many techniques are available, however,that  can shed considerable l i g h t on underlying ecological struc-  ture i f the r e s u l t s are c a r e f u l l y evaluated and the methodological  aseu---  sumptions are consistent with the data c o l l e c t i o n and data base i t s e l f . The techniques used i n analysing my data overlap to a certain extent. Such overlap i s not necessarily redundant, as i t w i l l provide points of  32  c o n t a c t between t h e t e c h n i q u e s t h a t w i l l be h e l p f u l i n e v a l u a t i n g t h e i r efficiency. The d i v e r s i t y a n a l y s i s i s the l e a s t o v e r l a p p i n g o f t h e s e t o f analyses.  C o n c e p t u a l l y , d i v e r s i t y can be c o n s i d e r e d t o be r e l a t e d t o  the u n c e r t a i n t y i n v o l v e d i n p r e d i c t i n g which s p e c i e s an a n i m a l would be c o n f r o n t e d w i t h i n i t s n e x t random e n c o u n t e r w i t h a n o t h e r a n i m a l ( L l o y d et a l . I968).  I f d i v e r s i t y measurements a r e made on t h e same community  a,t d i f f e r e n t t i m e s , observed d i f f e r e n c e s i n d i v e r s i t y w i l l be due d i f f e r e n c e s i n t h e r e l a t i v e numbers o f s p e c i e s as w e l l as i n the number o f i n d i v i d u a l s .  to total  By comparing t h e d i f f e r e n c e i n d i v e r s i t y between  the b e g i n n i n g and end o f a time p e r i o d w i t h f l u c t u a t i o n s d u r i n g the p e r i o d , i t s h o u l d be p o s s i b l e t o t e s t f o r t h e p r e s e n c e o f t e m p o r a l i n t h e d i v e r s i t y o f the system. fully  Hummon (1974), f o r example, has  used a s i m i l a r i t y i n d e x o f h i s own d e s i g n ( S ) u r  time trends  success-  to investigate  n  t e m p o r a l and s p a t i a l r e l a t i o n s h i p s among i n t e r t i d a l marine g a s t r o t r i c h s . He examined d a t a f r o m a one y e a r p e r i o d o n l y , however, and the  temporal  b i a s i n h i s r e s u l t s r e l a t e s more t o a n n u a l c y c l i n g than t o l o n g term fluctuation. The  o t h e r a n a l y s e s which I have used a r e more c l o s e l y  Three o f the t e c h n i q u e s  ( c o r r e l a t i o n , c a n o n i c a l a n a l y s i s and  yield a probability level, n u l l hypothesis.  'p , 1  regression)  which can be used t o a c c e p t o r r e j e c t a  S i g n i f i c a n c e l e v e l s f o r 'p' a r e p r i m a r i l y a f u n c t i o n  o f convenience,  w i t h the 1% and %  Cochran I967) .  I have d i v i d e d t e s t s which show p^<  r a n g e s of s i g n i f i c a n c e : 0.015 C h o o s i n g p '< 0.05  interrelated.!  l e v e l s most o f t e n used (Snedecor and  p, 0.01*  p^:  would be more r e a s o n a b l e  0.05,  0.10  into three  0.05-< p '<  0.10.  on a s t a t i s t i c a l b a s i s ;  33  however, s i n c e t h e number of samples i s s m a l l , t h e r e i s a h i g h e r p r o b a b i l i t y of c o m m i t t i n g a t y p e - I I e r r o r ( i . e . a c c e p t i n g H actually false). and  I f p '< 0.05  when i t i s  q  were the s o l e c r i t e r i o n f o r s i g n i f i c a n c e ,  a l l s t a t i s t i c a l l y i n s i g n i f i c a n t c o r r e l a t i o n s or r e g r e s s i o n s were d i s -  c a r d e d , a r e l a t i o n s h i p f o r which p = 0.075 would be i g n o r e d .  Such a  r e l a t i o n s h i p , however, might have a sound b i o l o g i c a l b a s i s which would aid  i n the i n t e r p r e t a t i o n of the a n a l y s i s .  information  Hence, p o t e n t i a l l y v a l u a b l e  might be l o s t by c u r t a i l i n g the a n a l y s i s of b o r d e r l i n e  s i g n i f i c a n t a t l e v e l s o f 'p' between 0.05  and  0.10.  The  use  of a  cases slight-  l y higher s i g n i f i c a n c e l e v e l minimizes t h i s p o s s i b i l i t y .  Subdividing  the s i g n i f i c a n t r e l a t i o n s h i p s a c c o r d i n g t o the degree of  significance  isolates relationships whichdhavetstatisticalesignificaricesfrom  those  w i t h d e b a t a b l e s t a t i s t i c a l s i g n i f i c a n c e but which s t i l l might be  helpful  i n u n d e r s t a n d i n g the p r o c e s s e s b e i n g e v a l u a t e d . The analysis.  f i r s t o f the i n t e r r e l a t e d a n a l y s e s i s m u l t i p l e  correlation  M u l t i p l e c o r r e l a t i o n a n a l y s i s i n d i c a t e s the degree and  of i n t e r a c t i o n o c c u r r i n g between d i f f e r e n t s p e c i e s . t e c h n i q u e which i s l e a s t s u s c e p t i b l e p r e t e d ; however, i t may  I t i s p e r h a p s the  t o d i s t o r t i o n and  most r e a d i l y i n t e r -  a l s o y i e l d the l e a s t i n f o r m a t i o n .  C l u s t e r ana'A  l y s i s w i l l f u r t h e r r e f i n e the d a t a a n a l y s i s by c o n s t r u c t i n g of s i m i l a r l y v a r y i n g s p e c i e s . can then be examined, and rence  The  types  aggregations  s p e c i e s c o m p o s i t i o n of t h e s e c l u s t e r s  a b i o l o g i c a l or p h y s i c a l b a s i s f o r t h e i r o c c u r -  postulated. Groups of s i m i l a r s p e c i e s may  mental f a c t o r s .  The  have s i m i l a r r e s p o n s e s t o  environ-  demonstrated r e l a t i o n s h i p between such groups  e n v i r o n m e n t a l c h a r a c t e r i s t i c s ( e . g . B a r y 1963a, b, c, 1964;  Fager  and and  34  McGowan 1963) i n d i c a t e s t h a t e n v i r o n m e n t a l p a r a m e t e r s * p l a n k t o n abundance.  often c o n t r o l zoo-  C a n o n i c a l c o r r e l a t i o n i s a s t a t i s t i c a l method f o r  comparing i n t e r c o r r e l a t i o n s between two c o n c e p t u a l l y d i f f e r e n t domains measured w i t h i n a s i n g l e system  ( C o o l e y and Lohnes 1971) •  Although i t  was; d e v e l o p e d f o r t y y e a r s ago by H o t e l l i n g (1935, 1936), c a n o n i c a l c o r r e l a t i o n h a s n o t been w i d e l y used i n t h e a n a l y s i s o f z o o p l a n k t o n d a t a . The major o b j e c t i o n t o t h i s method i s t h a t t h e c o r r e l a t i o n  coefficient  g e n e r a t e d i s o n l y a measure o f t h e o v e r l a p between two m a t h e m a t i c a l l y d e r i v e d c a n o n i c a l v a r i a t e s which a r e n o t n e c e s s a r i l y i m p o r t a n t compon e n t s o f t h e i r r e s p e c t i v e d a t a s e t s ( C o o l e y and Lohnes 1971)•  The  d e r i v a t i o n o f a "redundancy i n d e x " by S t e w a r t and Love (1968) has p r o v i d e d a means o f e s t i m a t i n g t h e a c t u a l degree o f o v e r l a p between t h e twon domains a s r e p r e s e n t e d i n t h e f i r s t and subsequent p a i r s o f c a n o n i c a l variates. There i s c o n s i d e r a b l e a p r i o r i  s u p p o r t f o r t h e assumption  d i t i o n s d u r i n g t h e s p r i n g bloom and t h e l e s s prominent  t h a t con-  f a l l bloom, w i t h  i t s a s s o c i a t e d i n t r u s i o n o f o c e a n i c water, may be i m p o r t a n t f a c t o r s i n r e g u l a t i n g the s i z e o f overwintering p o p u l a t i o n s of zooplankton species. By s e l e c t i n g b l o c k s o f h y d r o g r a p h i c and b i o l o g i c a l d a t a t h a t a r e tempo:-?ar a l l y s e p a r a t e d , and c a l c u l a t i n g t h e c a n o n i c a l c o r r e l a t i o n  coefficient  and t h e redundancy between c a n o n i c a l f a c t o r s o f d t h e s e b l o c k s , t h e p o s s i b l e e f f e c t o f t h e h y d r o g r a p h i c regime a t one t i m e o f t h e y e a r on t h e b i o l o g i c a l regime a t a l a t e r d a t e may be e x p l o r e d . The f u n c t i o n a l r e l a t i o n s h i p between i n d i v i d u a l s p e c i e s and h y d r o g r a p h i c parameters  i s a l s o o f i n t e r e s t and can be i n v e s t i g a t e d by mul-  t i p l e regression analysis.  A l t h o u g h my d a t a do n o t adhere s t r i c t l y t o  35  t h e a s s u m p t i o n s u n d e r l y i n g t h e c l a s s i c a l l i n e a r r e g r e s s i o n model,  devi-  a t i o n s from t h e model a r e s m a l l , and t h e i n t e n t o f t h e a n a l y s i s i s n o t so much r i g o r o u s as i t i s h e u r i s t i c .  L i n e a r r e g r e s s i o n i s most o f t e n  used i n t h e e v a l u a t i o n o f e x p e r i m e n t a l d a t a , when t h e independent v a r i a b l e can be measured w i t h o u t e r r o r ( e . g . d r u g dosages, exposure t i m e s , ...).  I am e s s e n t i a l l y comparing t h e v a r i a t i o n i n h y d r o g r a p h i c parame-  t e r s a t a s e r i e s of s p e c i f i c depths w i t h p o p u l a t i o n s t h a t are found over a depth range.  The h y d r o g r a p h i c p a r a m e t e r s r e p r e s e n t t h e h y d r o g r a p h i c  regime over a d e p t h range, however, and a r e an i n d e x o f t h e g e n e r a l cond i t i o n s t o which a s p e c i e s i s exposed.  The e r r o r i n v o l v e d I n t h e measure-  ment o f such p a r a m e t e r s i s s u f f i c i e n t l y s m a l l t h a t i t w i l l be c o n s i d e r e d n e g l i g i b l e i n terms o f t h e b i o l o g i c a l e f f e c t s i n w h i c h I am  interested.  F o r example, t e m p e r a t u r e measurements can be made w i t h an e r r o r o f about + 0.02  G°, a s m a l l e r r o r compared t o t h e range o f t e m p e r a t u r e s  l i k e l y t o be f o u n d o v e r t h e d u r a t i o n o f s a m p l i n g a t any one d e p t h a t Geo 17*4-8.  Such r a n g e s s h o u l d be on t h e o r d e r o f 0.50  G° o r l a r g e r .  Trends w i t h i n a b l o c k o f s i m i l a r measurements become d i f f i c u l t t o d e s c r i b e as t h e amount o f d a t a c o l l e c t e d i n c r e a s e s ( G r i e g - S m i t h 1971)• I t i s i m p o s s i b l e , however, t o c o l l e c t o n l y t h o s e d a t a which w i l l meaningful!  be  F a c t o r a n a l y s i s can reduce complex d a t a b l o c k s t o a r e l a t i v e -  l y few i m p o r t a n t f a c t o r s .  The degree t o which d a t a can be r e d u c e d i s an  i n d e x o f t h e redundancy o f t h e measurements.  The f a c t o r s g e n e r a t e d can  o f t e n , but n o t a l w a y s , be i n t e r p r e t e d i n b i o l o g i c a l terms. F a c t o r a n a l y s i s i s a c t u a l l y a g e n e r a l term f o r a v a r i e t y o f p r o c e d u r e s ( C o o l e y and Lohnes 1971)•  The b a s i c t e c h n i q u e was  originally  "developed by p s y c h o l o g i s t s as a t o o l f o r measuring t h e u n d e r l y i n g  traits  36  i n a b l o c k of c h a r a c t e r d a t a (Anderson I963)•  A few f a c t o r a n a l y t i c a l  methods have been s u c c e s s f u l l y used i n t h e a n a l y s i s of z o o p l a n k t o n ( e . g . A n g e l and Fasham 1973,  i9?4-, 1975;  W i l l i a m s o n 1961,  data  1963).  One  o f t h e s e i s p r i n c i p a l components a n a l y s i s (PGA). P r i n c i p a l components a n a l y s i s i s complementary t o c l u s t e r a n a l y s i s . L i k e o t h e r f a c t o r i n g methods, PGA s i m i l a r i t y data.  I n PGA,  e x t r a c t s f a c t o r s f r o m an a g g r e g a t e of  the f i r s t f a c t o r e x t r a c t e d i s the f a c t o r ac-  c o u n t i n g f o r most o f t h e c o v a r i a n c e among t h e v a r i a b l e s . f a c t o r i s o r t h o g o n a l t o the f i r s t ,  The  next  and hence u n c o r r e l a t e d w i t h i t .  It  i s the next h i g h e s t c o n t r i b u t o r t o the covariance.  A succession of f a c -  t o r s can be e x t r a c t e d - t h e number b e i n g d e t e r m i n e d  by t h e  meaningfulness  of the f a c t o r s and by t h e b a l a n c e between the degree o f  c o m p l e x i t y encountered son 1961,  ecological  and t h e degree of completeness c f e s i i e d d ( W f l l i a m s -  I963; O r l o c i 1973).  The advantage o f PGA  i s that i t i s a  s t a t i s t i c a l method of d e s c r i b i n g i n t e r r e l a t i o n s h i p s i n terms o f a s m a l l number of f a c t o r s ( R o h l f and S o k a l I962). i s t h a t even t h e " i m p o r t a n t " f a c t o r s may ( G o o d a l l 1954).  Normally,  The p r o b l e m w i t h t h i s method, have no b i o l o g i c a l meaning  however, the a r i t h m e t i c a l f a c t o r s can  be  a s s o c i a t e d w i t h known b i o l o g i c a l p a r a m e t e r s ( e . g . W i l l i a m s o n I963; G a s s i e and M i c h a e l I968). B o t h p r i n c i p a l components and c l u s t e r a n a l y s i s have been  criticized  as b e i n g t o o s u s c e p t i b l e t o d i s t o r t i o n a n d i i n g e n e r a l t o o c o m p l i c a t e d g i v e meaningful 1973)•  r e s u l t s ( B e a l s 1973;  O r l o c i 1973;  to  W h i t t a k e r and Gauch  P a r t of t h e d i s t o r t i o n i s caused by t h e f u n d a m e n t a l c l a s h be-  tween t h e l i n e a r i t y o f the models and t h e n o n - l i n e a r i t y of t h e ecosystem. T h i s d i s t o r t i o n s h o u l d be r e d u c e d i n my d a t a , as t h e y a r e a r r a y e d a.  along  37  a t e m p o r a l a x i s , r a t h e r t h a n a l o n g a complex g r a d i e n t , t i v e of t h e a n a l y s i s i s t o i n v e s t i g a t e p a t t e r n s  and  the  objec-  of v a r i a t i o n w i t h i n - a  community r a t h e r t h a n e n v i r o n m e n t a l c o r r e l a t e s w i t h communities A l l e n I968). PGA  F u r t h e r m o r e , B e a l s (1973) s u g g e s t s t h a t methods such  a r e more m e a n i n g f u l when a p p l i e d t o a narrow range of t h e  ment , where t h e communities i n q u e s t i o n e t a l . (1972) a l s o f o u n d t h a t PGA t h a n was  (e.g.  cluster analysis.  was  environ-  approach homogeneity.  more s e n s i t i v e t o  as  Hughes  heterogeneity  R e s t r i c t i n g t h e a n a l y s i s o f my d a t a t o  s i n g l e community under c l o s e l y s i m i l a r e n v i r o n m e n t a l c o n d i t i o n s duces a degree of homogeneity which s h o u l d enhance t h e of p r i n c i p a l components a n a l y s i s .  The  a  intro-  effectiveness  o t h e r advantage of PGA  t h e a n a l y s i s g e n e r a t e s the r a n k o r d e r of each s t a n d a r d i z e d  i s that  case on each  component, f a c i l i t a t i n g t h e a s s o c i a t i o n of components w i t h d e f i n e d ments o f the d a t a ,  seg-  and making the a s s o c i a t i o n of b i o l o g i c a l meaning  w i t h t h e components l e s s h a z a r d o u s . B a s i c f a c t o r a n a l y s i s of the t y p e c a r r i e d out by the UBG  library  programme *BAN g i v e s s i m i l a r r e s u l t s t o p r i n c i p a l components a n a l y s i s , and  has been used more e x t e n s i v e l y i n p l a n k t o n r e s e a r c h .  as a v a i l a b l e i s more f l e x i b l e t h a n PGA, s p e c i e s may axis.  The  be r e a d i l y grouped a c c o r d i n g f a c t o r s produced may  and  has  The  programme  the advantage t h a t  t o t h e i r r e l a t i o n s h i p w i t h each  be r o t a t e d t o f i n d an o r i e n t a t i o n which  might be more r e a d i l y i n t e r p r e t e d i n terms of the b i o l o g y of t h e  system.  V a r i m a x r o t a t i o n , which I have used, r o t a t e s the axes i n o r d e r t o up"  "clean  t h e f a c t o r s t r u c t u r e by s i m p l i f y i n g the columns o f the f a c t o r m a t r i x  ( C o o l e y and Lohnes 1971) •  I t i s p e r h a p s the most a c c e p t a b l e of  p o s s i b l e r o t a t i o n s ( G l a s s and  Taylor  I966) .  the  Because of i t s f l e x i b i l i t y ,  38  t h i s method o f f a c t o r a n a l y s i s was used t o examine r e l a t i o n s h i p s  within  t h e z o o p l a n k t o n b a s i c d a t a b l o c k , w h i l e PCA was used t o f a c t o r t h e h y d r o g r a p h i c d a t a and a l s o t h e z o o p l a n k t o n c o r e s p e c i e s d a t a .  39  Results Hydrographic regime during the study period A v i s u a l inspection of the temperature and s a l i n i t y data i n d i cates that the general features of the d i s t r i b u t i o n of hydrographic parameters comform with previously published descriptions of the hydrography of the S t r a i t of Georgia (Tully and Dodimead 1957; Waldichuk 1957; Gardner 1972; Evans 1973).  The annual f l u c t u a t i o n of hydrographic  properties i s t y p i f i e d by the f l u c t u a t i o n i n 1971/72 (Figs. 3c, 4c). In spring, the upper part of the water column i s strongly s t r a t i f i e d as a r e s u l t of the warming of surface water by i n s o l a t i o n and lowering of surface s a l i n i t i e s due to runoff.  The near surface density gradient i s  a maximum at t h i s time, exceeding 1.00 (sigma-t units per meter increase in depth) i n June.  Waters deeper than 200 m are cool (less than 8.5 C)  and have almost no temperature gradient. The s a l i n i t y i s l e s s than ° . 31 °/oo,,anddthe deep water s a l i n i t y gradient i s weak. In l a t e summer, the intrusion of warm, high s a l i n i t y deep water formed by mixing processes i n the Southern Approaches i s the most s t r i king feature of the hydrographic regime.  S a l i n i t y in the deep water has  increased to 31-15 °/oo, and a l l temperatures are close to 9-0 G.  Des-  p i t e the change i n temperature and s a l i n i t y d i s t r i b u t i o n s i n spring and f a l l , s t r a t i f i c a t i o n i n water deeper than 50 m i s s t i l l very weak.  Near  surface s t a b i l i t y i s r e l a t i v e l y high i n August, but decreases considerably by September due largely to atmospheric cooling. By November, further intrusions originating i n the Southern Approaches have entered the deep basin of the S t r a i t of Georgia and i n creased the s a l i n i t y and temperature of the near bottom water at Geo  1748.  40 a  Figure 3(a-e):  Temperature i s o p l e t h s , i n G, a t Geo 1748 between I969 and 1974. Dotted l i n e s (...) i n d i c a t e i n t e r p o l a t i o n s over m i s s i n g d a t a p o i n t s . Dashed l i n e s ( ) indicate t h e 9-0 G i s o p l e t h . S a m p l i n g d e p t h s a r e indicated with a small dot.  40b TIME (month)  40c  4-ia  Figure 4(a-e):  S a l i n i t y isopleths, i n ° / , f o r f i v e consecutive years at Geo 1748. Dotted l i n e s (.vdi<?<)/fc§ndicate interpolations over missing data points. Dashed l i n e s ( ) indicate the 31 ° / isopleth. Sampling depths are indicated with a small dot. 0 0  00  TIMEfrttnths)  41c  42  The g r e a t e s t change, however, i s i n t h e upward e x t e n t of h i g h s a l i n i t y water.  Water of g r e a t e r than 31 ° /  00  has r e a c h e d 250 m i n November,  compared w i t h 300 m i n September, and a l l d e p t h s between 50 and 390 show i n c r e a s e d s a l i n i t y .  m  S a l i n i t i e s and t e m p e r a t u r e s from deeper t h a n  50 m a r e g e n e r a l l y h i g h e r i n ' w i n t e r than a t any o t h e r t i m e o f t h e y e a r . Stability  i s s t i l l low i n deep and i n t e r m e d i a t e w a t e r s , b u t has a l s o  dropped i n n e a r s u r f a c e water.  The d e n s i t y g r a d i e n t i n December i s I s  l e s s t h a n OiOlnjihroughoutmthe water column, and t h u s b a r r i e r s t o v e r t i c a l movement a r e m i n i m i z e d . A l t h o u g h t h e above d e s c r i p t i o n i s based on e v e n t s i n 1971/72, i t i s r e p r e s e n t a t i v e o f t h e average a n n u a l c y c l e of h y d r o g r a p h i c p r o p e r ties.  To p u t t h i s p a r t i c u l a r y e a r i n t o p e r s p e c t i v e , i t must be compared  t o t h e o t h e r y e a r s f o r whichddata a r e a v a i l a b l e .  I n t h i s way,  changes  i n h y d r o g r a p h i c s t r u c t u r e t h a t r e l a t e t o l o n g - t e r m t r e n d s can be  isolated.  The a n n u a l d i s t r i b u t i o n s o f temperature and s a l i n i t y have been p l o t ted  f o r each y e a r o f t h e s u r v e y ( F i g s . 3, 4 ) .  The t i m e p e r i o d from A p r  A p r i l t h r o u g h A p r i l o f t h e f o l l o w i n g y e a r was used i n o r d e r t o b r a c k e t the  f a l l i n t r u s i o n , which extends p a s t the end of t h e c a l e n d a r y e a r .  W i t h one e x c e p t i o n , t h e r e has been a g r a d u a l i n c r e a s e i n t h e s a l i n i t y the  i n t r u d i n g water mass throughout t h e s t u d y p e r i o d .  of  This feature i s  more r e a d i l y seen by examining s a l i n i t y a t s e l e c t e d d e p t h s d u r i n g s u c c e s s i v e Decembers ( F i g . 5)-  P i c k a r d (1975), examining t h e same pheno-  menon over a s h o r t e r t i m e p e r i o d , f e l t t h a t i t i n d i c a t e d a t r e n d i n t h e S t r a i t o f G e o r g i a toward h i g h e r s a l i n i t i e s i n deep water, b u t t h a t such changes were q u i t e s m a l l . The changes i n s a l i n i t y a r e more a p p a r e n t when d a t a from 1974- a r e  43*  F i g u r e 5:  F l u c t u a t i o n s i n s a l i n i t y a t s e l e c t e d depths i n s u c c e s s i v e Decembers a t Geo 1748. (Data f o r 1972 a r e from November)  43b  29.60 • V U  '68  1  '69  1  70  L  _L  I  VI  72  73  L  74  YEAR  1  44  added t o P i c k a r d ' s d a t a .  I n 1973/4, s a l i n i t i e s exceeded 31.25  a t d e p t h s g r e a t e r than 300 m.  °/  0 0  T h i s h i g h e r t h a n normal s a l i n i t y was  apparent a t o n l y one d e p t h i n t h e p r e c e d i n g y e a r (390 m i n November), and was n o t p r e s e n t i n any o t h e r y e a r , w i t h one e x c e p t i o n . was I970/7I,  The e x c e p t i o n  when t h e a n n u a l c y c l e i n deep water was v e r y s i m i l a r t o t h e  c y c l e i n 1973/74.  W i t h o u t t h e d a t a from 1970/71, i t would be t e m p t i n g  t o p o s t u l a t e a l o n g - t e r m t r e n d i n t h e deep water h y d r o g r a p h i c regime in the S t r a i t ofGeorgia.  With t h i s d a t a , however, i t i s l e s s p r o b a b l e  that the trend i s s i g n i f i c a n t . S i m i l a r t r e n d s i n t h e t e m p e r a t u r e v a r i a t i o n over t h e s t u d y p e r i o d can a l s o be d e s c r i b e d ; however, t h e t r e n d s a r e more tenuous.  Tempera-  t u r e s above 9-0 G a t d e p t h s g r e a t e r t h a n 50 m a r e l e s s common i n t h e l a t t e r h a l f o f t h e s a m p l i n g p e r i o d than i n t h e f i r s t h a l f .  Temperatures  below 9-0 G p r e v a i l e d i n most o f t h e water column f o r two s u c c e s s i v e y e a r s (1971/72,  1972/73), b u t i n t h e l a s t y e a r f o r which d a t a a r e a v a i l -  a b l e (1973/7*+) t h e 9-0 G i s o t h e r m once more r e a c h e d t h e d e e p e s t d e p t h s sampled.  The a b s o l u t e changes a r e s m a l l .  Deep water t e m p e r a t u r e s o f  g r e a t e r t h a n 9-5 0 o r l e s s than 8 . 7 5 0 were r a r e l y n o t e d . Combining b o t h t e m p e r a t u r e and s a l i n i t y d a t a , i t appears t h a t t h e r e has been a s l i g h t s h i f t i n t h e h y d r o g r a p h i c regime o f t h e S t r a i t o f Georgia w i t h i n the study period.  T h i s s h i f t i s due p r i m a r i l y t o i n -  c r e a s e s i n t h e s a l i n i t y o f water i n t r u d i n g from t h e S o u t h e r n Approaches. The temperature regime a l s o appears t o have s h i f t e d , towards c o o l e r deep water, b u t t h e v a r i a t i o n s i n v o l v e d a r e l e s s i n d i c a t i v e o f a t r e n d t h a n a r e t h e v a r i a t i o n s •in, s a l i n i t y . 5  These changes i n t h e hydrography may be r e l a t e d t o a l o n g - t e r m  45  a l t e r a t i o n of t h e g e n e r a l h y d r o g r a p h i c c h a r a c t e r o f t h e S t r a i t .  Alter-  n a t i v e l y , i n view o f t h e d e v i a t i o n i n t h e 1 9 7 0 / 7 1 d i s t r i b u t i o n of s a l i n i t y and t h e g e n e r a l v a r i a b i l i t y i n t h e t e m p e r a t u r e f i e l d ,  t h e changes  may be p a r t o f a normal c y c l i c f l u c t u a t i o n w i t h a p e r i o d of g r e a t e r t h a n f i v e years. The r o l e o f t h e s e h y d r o g r a p h i c changes on t h e z o o p l a n k t o n i s d i f f i c u l t to assess without f u r t h e r a n a l y s i s .  The a b s o l u t e v a l u e s o f t h e  changes i n t e m p e r a t u r e and s a l i n i t y a r e s m a l l compared t o t t h e range i n the  same p a r a m e t e r s w i t h i n t h e water column.  However, t h e c h a n g i n g h y d r o -  graphy r e f l e c t s v a r i a t i o n i n t h e f o r m a t i o n o f t h e water masses of t h e S t r a i t of Georgia.  The changes observed i n deep water, f o r example,  w i l l be r e l a t e d t o t h e p h y s i c a l m i x i n g p r o c e s s e s i n t h e S o u t h e r n Approaches.  I n c r e a s i n g s a l i n i t y of i n t r u d i n g deep water can r e s u l t from  i n c r e a s e d s a l i n i t y o f i n c o m i n g Juan de F u c a deep water, o r from v a r i a t i o n s i n t h e degree o f m i x i n g between t h e Juan de F u c a water and o u t g o i n g f r e s h e r water.  I n t h e former c a s e , t h e i n f l u x o f water o f h i g h e r  t h a n normal s a l i n i t y from Juan de F u c a might r e f l e c t more i n t e n s i v e u p w e l l i n g o f f s h o r e and l e s s d i l u t i o n of t h e u p w e l l e d water.  In the  l a t t e r case, p r o p e r t i e s o f t h e m i x i n g water masses o t h e r than s a l i n i t y (e.g.  o r g a n i c carbon c o n t e n t , t r a c e m e t a l c o n t e n t , p a r t i c u l a t e c o n t e n t ,  ...) w i l l a l s o v a r y due t o v a r i a t i o n s i n t h e degree o f m i x i n g .  In  e i t h e r case, t h e c o m p o s i t i o n of t h e i n t r u d i n g water w i l l be c h a n g i n g , and t h e s e changes may be a f f e c t i n g t h e z o o p l a n k t o n community. Temperatures w i l l a l s o be a f f e c t e d by f l u c t u a t i o n s i n t h e format i o n o f water d e s t i n e d t o move i n t o t h e S t r a i t o f G e o r g i a .  In addition,  n e a r s u r f a c e water i n t h e S t r a i t w i l l be s e n s i t i v e t o a t m o s p h e r i c  46  fluctuations.  The changes i n t h e temperature and s a l i n i t y f i e l d s a r e  t h u s i n d i c a t i v e o f changes i n o t h e r , l e s s r e a d i l y d e f i n e d , water parameters  i n the S t r a i t of Georgia.  quality  Whether o r n o t t h e s e changes a r e  a s s o c i a t e d w i t h and perhaps r e s p o n s i b l e f o r concomitant changes w i t h i n t h e z o o p l a n k t o n community i s a q u e s t i o n which I hope t o answer i n t h e following analysis.  R e s u l t s o f sample s o r t i n g A t o t a l o f 22 v e r t i c a l h a u l s c o v e r i n g t h e p e r i o d from I969 t o December 1974 were s o r t e d .  October  E l e v e n o f t h e s e samples were t r u e  " w i n t e r d a t a " and a r e included, i n t h e a n a l y s e s r e p o r t e d here;, t h e o t h e r s were s p r i n g and summer d a t a used t o e s t a b l i s h t h e e x t e n t o f v a r i a t i o n d u r i n g t h e s p r i n g p h y t o p l a n k t o n bloom and i n e a r l y summer.  Over 75  d i f f e r e n t groups (Ta,ble I I ) were i d e n t i f i e d i n t h e c o u r s e ^ o f s o r t i n g t h e samples.  Most o f t h e s e were s i n g l e s p e c i e s , b u t some were groups  of a few s i m i l a r s p e c i e s t h a t c o u l d n o t be r e a d i l y d i f f e r e n t i a t e d , w h i l e o t h e r s were s u b s e t s o f t h e same'species. one m i l l i o n i n d i v i d u a l organisms  These groups r e p r e s e n t almost  s o r t e d and r e c o r d e d i n t h e i n i t i a l  sample a n a l y s i s . The i n f l u e n c e o f t h e s u b a r c t i c P a c i f i c on t h e S t r a i t o f G e o r g i a suggests t h a t s p e c i e s found i h e t h e S t r a i t s h o u l d be p r e d o m i n a t e l y water o r u b i q u i t o u s s p e c i e s .  cold  L e B r a s s e u r and Kennedy (1972) v e r i f y t h a t  t h e s p e c i e s c o m p o s i t i o n o f t h e S t r a i t o f G e o r g i a i s almost i d e n t i c a l t o t h a t found a t ocean weather s t a t i o n "Papa", w i t h i n t h e s u b a r c t i c water mass, and i n my s t u d y t h o s e s p e c i e s o f t h e 75 i d e n t i f i e d f o r which adequate d i s t r i b u t i o n r e c o r d s e x i s t a r e n e a r l y a l l c o l d water o r widespread  Table I I :  L i s t of a l l species or groups sorted.  AMPHIPODA Caliiopus sp. **Cyphocaris challengerl **Euprimno abyssalis E, macropa Hyperia sp. Orchomenella sp. **Parathemisto p a c i f i c a **Scina borealis S t i l i p e s sp. CHAETOGNATHA **Sagitta elegans COELENTERATA Medusae **Aeglna sp. **Aequorea sp. Aglantha sp. Hyboecdon sp. Phialidium sp. Proboscidactyla sp. Rathkea.sp. .**Species A (unidentified) Siphonophora Chelophes appendlculata (?) Dimophyes a r c t i c a Lensia baryi **Muggia a t l a n t i c a **Nanomia bijuga N. cara Species B (unidentified)  COPEPODA  CTENOPHORA  Beroe cucumis Acartia c l a u s l i Pleurobrachia pileus **A. longiremus Aetidlus armatus EUPHAUSIIDAE A. pacificus Bradyldius saanichi **Euphausia p a c i f i c a Calanus cristatus Nematoscelis d i f f i c l l i s **C.. marshallae (Frost 1974) Thysanoessa longipes **C. pacificus (Woodhouse 1971) T. spin i f era **C. plumchrus (Marukawa 1921; Campbell 1934) **Candacia columblae POLYCHAETA Centropages abdominalis **Chiridlus g r a c i l i s Rhynchonerella angelini . Corycaeus anglicus Tomopteris renata Epilabidocera amphitrites **T. septentrionalis •"••Eucalanus bungii bungii unidentified l a r v a l forms Gaetanus intermedius **Gaidlus columbiae PTEROPODA G. pungens Heterorhabdus tanner! **Clione limacina **Metridia okhotensis **M. p a c i f i c a MISCELLANEOUS Microcalanus pigmaeus p u s i l l u s Oithona helgolandicus **Limacina sp. * * 0 . spinirostris **Oikopleura sp. Oncaea borealis Decapod larvae and adults **Pareuchaeta elongata (Campbell 1934': as Euchaeta f i s h larvae japonlca; see Appendix A) p a r a s i t i c copepods **Pseudocalanus minutus **Ostracods (unsorted) S caphocalanus brevicornis l a r v a l squid and octopus S c o l e c i t h r i c e l l a minor unidentified cumaceans S. subdentata unidentified mysids Spinocalanus brevicaudatus Tharybis f u l t o n i Tortanus discaudatus  NB: Unless another reference i s given above, the species were i d e n t i f i e d from zooplankton keys prepared by John Fulton (1968, 1972, 1973). The i d e n t i f i c a t i o n of some of the species was checked with Fulton s o r i g i n a l source. For further information, see Appendix A. • **These 29 species (or groups) were retained after i n i t i a l examination of the data. As two species were subdivided due to the presence of appreciable numbers of juvenile stages i n the samples, data were generated f o r 32 species/groups.  48  s p e c i e s ( e . g . E u c a l a n u s b u n g i i b u n g i i : D a v i s 1949, M o r i 1964; m a r s h a l l a e : F r o s t 1974;  Calanus  O i t h o n a s p i n i r o s t r i s : M o r i 1964; A c a r t i a l o n g i -  remus: D a v i s 1949, M o r i 1964; Oncaea h o r e a l i s (= c o n i f e r a ? ) : D a v i s  1949;  E u p h a u s i a p a c i f i c a : Ponomareva 1963; T o m o p t e r i s s e p t e n t r i o n a l i s : D a l e s 1957,  Tebble 1962; C y p h o c a r i s  jgl'igans: B i e r i 1959) •  c h a l l e n g e r i : Bowman and McLain 1967; S a g i t t a  I n a d d i t i o n , some s p e c i e s a r e endemic t o t h e S t r a i t  of G e o r g i a and n e i g h b o u r i n g  waters ( e . g . G a i d i u s columbiae P a r k  B r a d y i d i u s s a a n i c h i P a r k I966). to  t h e c o l d water r u l e .  1962)  There a r e o n l y two d e f i n i t e  1967;  exceptions  Calanus p a c i f i c u s ( v a r . c a l i f o r n i c u s B r o d s k y  i s a w a r m - t r a n s i t i o n a l water s p e c i e s found from 23°N l a t i t u d e t o  52°N l a t i t u d e a l o n g t h e w e s t t c o a s t o f N o r t h A m e r i c a . probably maintained  This species i s  i n t h e S t r a i t , o f G e o r g i a by t h e northward f l o w i n g Da-  v i d s o n C u r r e n t and C a l i f o r n i a C o u n t e r c u r r e n t  (Woodhouse 1971)•  Aetidius  armatus, a minor s p e c i e s i n t h e S t r a i t , has been d e s c r i b e d a s a t r o p i c a l and s u b t r o p i c a l s p e c i e s (.Davis l-949, tMori 1964), and may be m a i n t a i n e d i n ;  the S t r a i t o f G e o r g i a i n t h e same way a s C a l a n u s p a c i f i c u s . The i n i t i a l Table I I .  s p e c i e s l i s t was reduced t o t h e 29 s p e c i e s marked i n  The m a j o r i t y o f t h e s p e c i e s e l i m i n a t e d were r a r e s p e c i e s ap-  p e a r i n g i n o n l y a s m a l l p r o p o r t i o n o f t h e samples. in  c o n c e n t r a t i o n s t o o s m a l l t o be r e l i a b l e .  (=32  O t h e r s were p r e s e n t  The 29 s p e c i e s r e t a i n e d  s u b d i v i s i o n s ) , along with t h e i r corresponding  concentration values  over t h e p e r i o d o f t h e study, c o n s t i t u t e d t h e " b a s i c d a t a m a t r i x " . m a t r i x was then!"further r e d u c e d .  This  The r e s u l t i n g "core s p e c i e s m a t r i x " was  composed o f 20 s u b d i v i s i o n s : 14 t r u e s p e c i e s , 1 group.and 2 s u b d i v i d e d s p e c i e s ( s e e Table I I I ) . None o f t h e s p e c i e s e l i m i n a t e d t o form t h e c o r e s p e c i e s l i s t were i m p o r t a n t elements o f t h e biomass, n o r d i d t h e v a r i a n c e  Table I I I :  Proportion of each species i n each of the regions of the water column found at Geo 1748. Acronyms are included to f a c i l i t a t e l a t e r reference to the species i n figures.  REGION SPECIES **Cyphocaris challengeri **Euprimno abyssalis **Parathemisto p a c i f i c a Scina borealis **Sagitta elegans Aegina sp. Aequorea sp. **Medusa sp. A Muggia a t l a n t i c a **Nanomia bijuga Acartia longiremus **Calanus marshallae **C. pacificus **C. plumchrus Gandacia columbiae **Chiridius g r a c i l i s **Eucalanus bungii bungii Gaidius columbiae Metridia okhotensis **M. p a c i f i c a (* CIV) (< CIV) Oithona s p i n i r o s t r i s **Pseudocalanus minutus **Pareuchaeta elongata (< CIV) (* CIV) (total) **Euphausia p a c i f i c a **Tomopteris septentrionalis Clione limacina Limacina h e l i c i n a Oikopleura sp. **Ostraccds  Near Surface ACRONYM (0-75 m) CYPHOC EUPRIM PMISTO SCINA SAGELE AEGINA - AEQUOR MEDSPA MUGGIA • NANOM ACARLO CMARSH CPACI CPLUM CANDAC CHIRID EUCAL GAIDCO METOK MPAC1 MP AC 2 OSPIN PSEUDO PARI PAR2 . PARTOT EUPAC TOMSEP CLLIM LIMAC OIKOP OSTRAC  0.14  0.56 0.27 0.03 0.23 0.57 0.07 0.29  0.32  0.95  0.01 0.13 0.27  0.01  0.16  Intermediate (75-200. m) 0.17  0.28  0.51 0.17  0.10  0.43 0.30 0.35 0.54  0.18  0.05 0.07 0.16  0.10 0.42 0.02  0.46 0.03  0.02 0.21 0.10  0.57  0.44  0.15  0.27 0.35 0.71  0.10 0.19  0.06  0.46 0.20  0.04 0.40 0.02  0.41 0.24 0.02 0.45 0.50 0.39 0.13 0.31  Species marked with a double asterisk (**) are "core species"  Deep (200-350 m) 0.69 0.16  0.22 0.81  0.67 0.70 0.58 0.17 0.50 0.93 0.83  1.00  0.77 0.31 0.97 0.38 0.97 0.94 0-39 0.33 O.98  . 0.41 0.32  0.40 0.28  0.45 0.31 0.55  0.41  0.49  50  i n t h i n t h e i r concentrations i n d i c a t e the presence of l a r g e annual f l u c t u a t i o n s i n t h e i r numbers. D a t a from t h e 24 Clarke-Bumpus samples t h a t were c o m p l e t e l y were ..used t o e s t i m a t e t h e p r o p o r t i o n of each s p e c i e s i n each c a l l y d e f i n e d r e g i o n of t h e water column ( T a b l e I I I ) .  sorted  hydrographi-  These p r o p o r -  t i o n s a r e c o n s i s t e n t w i t h the a v a i l a b l e d a t a on the v e r t i c a l d i s t r i b u t i o n s of the s p e c i e s s o r t e d (e.g. F u l t o n  I968; Gardner  1972;  Evans 1973)•  The' p r o p o r t i o n s were'-then:.used^to: c a l c u l a t e -the a c t u a l number per.-cubic m e t e r - o f each s p e c i e s ' i n each r e g i o n of t h e water column. I f the c o n c e n t r a t i o n v a l u e s f o r t h e t h r e e C a l a n u s s p e c i e s a r e  isola-  t e d f r o m t h e b a s i c d a t a m a t r i x ( T a b l e I V ) , the e x t e n t o f the f l u c t u a t i o n s t h a t t h e y underwent d u r i n g t h e sampling p e r i o d can be examined.  The  f l u c t u a t i o n s a r e n o t as e x t e n s i v e as t h e y i n i t i a l l y appeared t o be i n f a l l 1971•  November 1971  was  an u n u s u a l l y p o o r month f o r C a l a n u s plum-  c h r u s , a c c e n t u a t i n g the a p p a r e n t d i f f e r e n c e between 1971 e v e r , p r i o r t o November 1971  and 1970.  How-  the c o n c e n t r a t i o n of C a l a n u s plumchrus  w i t h one e x c e p t i o n , always g r e a t e r than t h a t of C. m a r s h a l l a e ,  while  d u r i n g and a f t e r November 1971  C. m a r s h a l l a e  merous than C. plumchrus .  c o n c e n t r a t i o n o f C a l a n u s p a c i f i c u s was  The  comparable t o t h a t o f C. m a r s h a l l a e was  was  was,  c o n s i s t e n t l y more nu-  i n I969, but i n a l l o t h e r samples  c o n s i s t e n t l y lower. The raw z o o p l a n k t o n  Transforming  d a t a showed s i g n i f i c a n t skewness and k u r t o s i s . '  t h e d a t a e l i m i n a t e d the skewness and k u r t o s i s ( T a b l e V)  the transformed  d a t a c o u l d t h e n be used as i n p u t f o r s t a t i s t i c s  grammes s e n s i t i v e t o the n o r m a l i t y of the d a t a .  pro-  and  :  51  T a b l e IV:  The c o n c e n t r a t i o n s (no./m ) o f t h e t h r e e C a l a n u s s p e c i e s d u r i n g t h e s t u d y p e r i o d . Mean v a l u e s r e p r e s e n t t h e mean f o r one y e a r based on t h e o v e r w i n t e r i n g samples.  SPECIES plumchrus By month Mean  0, aG:rsmarshallae Byymonthh Mean  C_. p a c i f i c u s By month Mean  Oct 69 Nov 69 Dec 69  72.20 25-61 48.96  48.93  23.07 29.70 40.97  31.25  18.30 21.77 27.^5  22.51  Nov 70 Dec, • 70  47.34 45.38  46.30  9.39 5.29  7-34  3.84 2.08  2.96  Nov 71 Dec 71  5.08 39-08  22.08  27.63 48.94  38.29  1.81 1.66  1.73  Dec  72  12.49  (12.49)  60.38  (60.38)  4.56  (4.56)  Nov 73 Dec 73  27.21 18.50  22.86  39.81 44.06  0.88 0.52  0.70  Dec  11.40  (11.40)  22.55  4.51  (4.51)  74  41.99  (22.55)  T a b l e V:  E f f e c t o f t r a n s f o r m i n g the raw d a t a on skewness and k u r t o s i s of two s p e c i e s (Calanus p l " * c h r u s (CPLUM) and Parathemisto p a c i f i c a (PMISTO)) and two months (October 1969 and December 1972; chosen a t random from the data m a t r i x . T e s t s f o r skewness and k u r t o s i s a r e from Geary (1936).  TRAN SFORMED DATA  RAW DATA ir(x.-x) n i SKEWNESS COEFFICIENT:  CPLUM  3  /b. (m ) 2  PMISTO  372  0.20 377  3  •iz(x.-x) n  1^1  2  I  0.08 3300  -Z(x.-x) n  0.86  x 0.81  0.45  0.61  -0.28  0.59 0.35 0.49  OCT 69  477  25300  2.43**  4.64  DEC 72  A 31  16800  1.88**  5.46  -6.31 TRANSFORMED DATA  2  /nE^-x)  where:  2  1 - 3 m, = — 2 ( x - x ) j n l  PMISTO  1.29  1.49  CPLUM  55.75  64.39  OCT 69  67.17  109.17  DEC 72  67.78  ^(x.-x) n 1  99.55  2  0.09  -3.45  v4(x,-x)  a -  -E(x.-x) n I -0.06  RAW DATA  KURTOSIS COEFFICIENT:  3  7n~~  /£(x x)  :  f  2.56  2.98  0.86 .  0.87  2.00  2.59  0.77  0.62**  8.98  10.77  0.83  9.14  11.21  0.82  0.87  0.68**  2  ** i m p l i e s a s i g n i f i c a n t c o e f f i c i e n t (p'<0.01). S i g n i f i c a n c e l e v e l s f o r both t e s t s f o r the range of sample s i z e s t e s t e d a r e found i n Geary (1936). n = 11 f o r t h e s p e c i e s d a t a , n = 25 f o r the October data and n = 23 f o r the December data A l l summations a r e summed over the range o f i = 1,2,3  n  53  D i v e r s i t y and  multiple  correlation  A l l of the d i v e r s i t y i n d i c e s were s t a b l e , and none showed t r e n d over the p e r i o d  examined.  d a t a b l o c k y i e l d e d 75  correlations  no  i n t u i t i v e pattern  F i f t e e n per  The  multiple  c o r r e l a t i o n of the  s i g n i f i c a n t a t p '< 0.10.  t o the d i s t r i b u t i o n of c o r r e l a t i o n s  c e n t of t h e  any  basic  There i s (Fig.  6).  c o r r e l a t i o n c o e f f i c i e n t s a r e s s i g n i f i c a n t (p '<  Table V I ) .  Table VI:  The numbers of s i g n i f i c a n t p o s i t i v e and n e g a t i v e c o r r e l a t i o n c o e f f i c i e n t s i n the s p e c i e s c o r r e l a t i o n m a t r i x (maximum p o s s i b l e number of c o r r e l a t i o n s i s 4-96) .  S i g n of  'r' (correlation  coefficient)  Significance  +  -  0.01  ^ p  9  0.01  < p '<  0.05  133  3 8  21  0.05  < p  '<  0.10  20  12  42  52  23  75  Totals  Cluster  total 12  analysis  Clustering  of the p a r t i t i o n e d d a t a withmmonths as  y i e l d s t h r e e c l u s t e r s d i s t i n c t a t the 0.50 r a n g i n g from 0.0  t o 1 .'0  ( F i g . 7)-  variables  l e v e l on a i s i m l l a r i t y  Each c l u s t e r c o n s i s t s  scale  of a l l of  d a t a from one  of the t h r e e r e g i o n s of the water column found a t  station.  o n l y e x c e p t i o n i s the i n c l u s i o n o f i n t e r m e d i a t e water  The  the  the  0.10;  54 a  Figure 6 :  Summary of the correlation c o e f f i c i e n t s between the zooplankton species i n the basic data matrix. Only correlations s i g n i f i c a n t at pf<0.10 are shown, and only the sign of the c o e f f i c i e n t i s given. Acronyms are as i n Table I I I .  54b  E U C A L l G A I D C O l M E TOK  I  M P A C 1  P S E U D O W  P A R T O T I E U P A C I T O M S E P  I  C L L I M l L I M A C I OIKOP  OSTRACEI  55 a  F i g u r e 7:  C l u s t e r i n g o f t h e p a r t i t i o n e d months. (A = n e a r s u r f a c e , B = i n t e r m e d i a t e , C = deep water)  S I M I L A R I T Y  o z > 70  O  m o  O C T  6 9 C  D E C  6 9 C  N O V  7 3 C  D E C  7 3 C  D E C  7 4 C  D E C  7 1 C  D E C  7 2 C  D E C  7 0 C  N O V  7 1 C  N O V  69C"  N O V  70C-  O C T  69A-  O C T  6 9 B -  D E C  69A-  N O V  70A-  D E C  7CA"  N O V  71A"  D E C  71A"  D E C  72A"  N O V  69A-  N O V  73A"  D E C  73A-  D E C  74A-  D E C  6 9 3 -  P E C  73Br  N O V  7 3 B "  D E C  7 4 B "  D E C  T I B -  D E C  7 2 B "  D E C  7 0 B -  N O V  71  N O V  6 9 B -  B-  N O V  70B~  p  O  p  O  CD  03  ^  O)  56  data from October 1 6 Q  Q  within the near surface water cluster.  There are  no major subdivisions in any of the three clusters; however, in both deep and intermediate water clusters there i s a tendency for November?)dataatoG be grouped separately from December data, and for data taken in the l a t ter part of the sampling period to be grouped separately from earlier data. Two major clusters of species were produced at a s i m i l a r i t y level of 0.12  (Fig. 8).  The f i r s t cluster contains 12 of the 32 species.  (N.B. Not a l l of the elements of the data matrices are true species, but are referred to as such for the sake of convenience).  Six of these  twelve species are the only true deep water species identified. f a l l into a single cluster separable at.the 0.50  level.  They  The other  six do not f a l l into any d i s t i n c t cluster, and include species with d i f f e r i n g depth distributions. The second major species cluster does not contain--any-large; wa-. ter type associated groups.. The only two species always found shallower than 200 m do not f a l l into any cluster at the 0.30  level.  The only two  species found i n both near surface and deep water, but uncommon at i n termediate depths, are similarly unclustered.  The remaining species  f a l l into a number of small clusters that appear not to be related to the region in which the species i s found, but rather to the region in which i t i s rarest.  For example, i n the cluster composed of Nanomia  bijuga, Pareuchaeta elongata  (5CIV  and t o t a l ) , Cyphocaris challenger!  and Sagitta elegans, which i s clustered at the O.65  l e v e l , a l l of the  species but Gyp'ohallengeri have a concentration minimum i n intermediate water, even though they have a measurable concentration in a l l three  57  F i g u r e 8:  C l u s t e r i n g of s p e c i e s , p a r t i t i o n e d d a t a . Acronyms as i n T a b l e I I I .  raw  a  S I M I L A R I T Y  O AEOUOR CLLIM OSPIN CPACI SCINA CANDAC M E TOK EUCAL CPLUM PSEUDO MPACI C MARSH ACARLO AEGINA  TJ m o m in  EU PAC OIKOP CHIRID MPAC2 LI M A C M E DSP A E U PRIM MUGGIA PMISTO PAR2 NANOM PARI PAR TOT CYPHOC SAGELE OSTRAC GAIDCO TOM S E P  o  o 0)  o  Ol  58  t y p e s o f water.  Cyphocaris  challengeri  has a c o n c e n t r a t i o n minimum i n  n e a r s u r f a c e water, but the c o n c e n t r a t i o n i n i n t e r m e d i a t e water i s a l m o s t S i m i l a r l y , the 0 s t r a c o d / G a i d i u s  i d e n t i c a l w i t h the minimum. Tomopteris s e p t e n t r i o n a l i s  columbiae/  c l u s t e r , formed a t the same s i m i l a r i t y l e v e l ,  shows a c o n c e n t r a t i o n minimum i n n e a r s u r f a c e w a t e r .  Canonical  correlation  G r o u p i n g core s p e c i e s by p a t t e r n of d e p t h d i s t r i b u t i o n , and r u n n i n g C a l a n u s plumchrus and G. m a r s h a l l a e s i x groups ( T a b l e V I l ) .  Table V I I :  Group 1  The  as s i n g l e s p e c i e s ,  s i g n i f i c a n t canonical correlation  yielded coefficients  G r o u p i n g of s p e c i e s by v e r t i c a l d i s t r i b u t i o n p a t t e r n .  Characteristics  Species  Minimum c o n c e n t r a t i o n a t i n t e r mediate d e p t h s , some v e r t i c a l migration  Euphausia p a c i f i c a Nanomia bi.juga Pareuchaeta elongata (<CIV and t o t a l ) S a g i t t a elegans  Minimum c o n c e n t r a t i o n i n deep water, Euprimno a b y s s a l i s but g r e a t e r than 10% of the p o p u l a Parathemisto p a c i f i c a t i o n i n each r e g i o n o f the water column Minimum c o n c e n t r a t i o n nearv.surface, most s p e c i e s w i t h a mid-depth maximum; a t l e a s t 1 0 % of t h e p o p u l a t i o n i n each r e g i o n o f the water column  Tomopteris s e p t e n t r i o n a l i s M e t r i d i a p a c i f i c a (<GIV) Chiridius gracilis Ostracods  A l l s p e c i e s w i t h a maximum c o n c e n t r a t i o n i n deep water, and a n e g l i g i b l e c o n c e n t r a t i o n ( l e s s than 10% of t h e t o t a l ) i n n e a r s u r f a c e water  a) C a l a n u s plumchrus P s e u d o c a l a n u s minutus M e t r i d i a p a c i f i c a (SCIV) Calanus marshallae Calanus p a c i f i c u s b) C a l a n u s plumchrus c) G. m a r s h a l l a e  59 ( R ' s ) between b l o c k s of z o o p l a n k t o n and b l o c k s o f h y d r o g r a p h i c  data  c  are,  w i t h o n l y t h r e e e x c e p t i o n s , a l l g r e a t e r than 0.95-  No  specific  t r e n d s appeared i n t h e c a n o n i c a l c o r r e l a t i o n s , much as w i t h t h e m u l t i ple  c o r r e l a t i o n r e s u l t s , and t h e o v e r a l l p i c t u r e i s s t i l l v e r y complex.  F o r example, t h e f i r s t  c a n o n i c a l f a c t o r f o r water column s t a b i l i t y i n  August and September has s i g n i f i c a n t r e l a t i o n s h i p s w i t h a l l but groups, and can a c c o u n t f o r over 95% p l u m c h r u s.  of t h e v a r i a t i o n i n C a l a n u s  The E u p h a u s i a p a c i f i c a / N a n o m i a b i j u g a group can be  t o almost a l l o f t h e f a c t o r s checked, w h i l e C a l a n u s m a r s h a l l a e s i g n i f i c a n t r e l a t i o n s h i p s w i t h temperature only. i s most s t r o n g l y r e l a t e d t o s t a b i l i t y to  stability  factors.  two  related shows  The deep w a t e r group  i n J u n e / J u l y , but i s a l s o r e l a t e d  i n phase and t h r e e months out o f phase, as w e l l as t o o t h e r  D e s p i t e t h i s i n h e r e n t c o m p l e x i t y , t h e r e appears t o be a d e f i -  n i t e r e l a t i o n s h i p between t h e h y d r o g r a p h i c p a r a m e t e r s , t e m p e r a t u r e and s a l i n i t y ,  and t h e z o o p l a n k t o n d a t a .  particularly  The r e s u l t s  are  summarized i n T a b l e V I I I .  Regression a n a l y s i s The r e g r e s s i o n a n a l y s i s ( T a b l e IX) s u p p o r t s t h e r e l a t i o n s h i p of z o o p l a n k t o n w i t h s t a b i l i t y and t e m p e r a t u r e . t h a t c a t e d by t h e c a n o n i c a l a n a l y s i s .  initially  Only 6 o f t h e 3*+ s i g n i f i c a n t  r e g r e s s i o n equations i n v o l v e s a l i n i t y . the f a c t o r s t h a t d e t e r m i n e s  was  stability,  Although  indi-  (p^O.10)  t e m p e r a t u r e i s one  of  t h i s a s s o c i a t i o n does n o t appear  t o be r e s p o n s i b l e f o r t h e f a c t t h a t each parameter g e n e r a t e s  a similar  number o f s i g n i f i c a n t r e g r e s s i o n e q u a t i o n s .  The m a j o r i t y (60$l) o f t h e  temperature r e g r e s s i o n s i n v o l v e temperatures  from 200  m or deeper, w h i l e  60  Table V I I I :  Summary o f t h e s i g n i f i c a n t c a n o n i c a l c o r r e l a t i o n  Group St 1  R  0.9978 c  0.05  P  %s  —-  23.0  2  2  -—  D a t a S i x Months Out of Phase  D a t a Three Months Out of Phase  D a t a i n Phase  T  S  coefficients.  T  St  S  St  0.9985  0.9978  0.9970  0.9946  0.9921  0.9979  0.05  0.10  0.10  0,05-  0.10  0.05  26.0  21.2  24.0  26.6  O.976O  R c  0.05  P  11.4  7.8 0.9971 0.9607 b.01 0.05 12.31 80.§P 0.9980  15.4  J  3  •—  R  0,9937  0.9995  0.01  0.05  0.9984  c  p 2  %s  —  4a R  -—  0.9999  c  0.01  P %S  26.4  2  c  c  0.9950  0.9974  0.05  0.10  0.10  0.05  25.1  22.7  where : 1  c  f<£  33.6  0.9907 0.9738 0.05 0.10 • X V 30 39.9 9  0.9918 j_  -  0.10  R  13.0  -  0.005  0-.-9383  0 *9881  0.10  0.005  88.0  79.5  2  27.7  98.4  0.8916  4c R  13.3  0.9958  76.8  2  fcS  51.7  0.05  0.9991  0.05  P  fs  —  0.8764  4b R  —  30.4  0.05  i s the canonical c o r r e l a t i o n  97.6  coefficient  2 i s t h e p e r cent of t h e v a r i a n c e i n t h e zooplankton accounted f o r by t h e h y d r o g r a p h i c f a c t o r  'p' i s t h e C h i - s q u a r e p r o b a b i l i t y T = temperature,  S = salinity,  that R  c  i s not s i g n i f i c a n t  St ==stability  A d o u b l e s e t o f v a l u e s i m p l i e s t h a t b o t h t h e f i r s t and second of c a n o n i c a l f a c t o r s were s i g n i f i c a n t l y c o r r e l a t e d  pairs  61  = 0.10.  T a b l e I X : Summary o f a l l r e g r e s s i o n e q u a t i o n s s i g n i f i c a n t a t  IN PHASE REGRESSIONS Temperature:  Stability:  GYPHOG = -1.02(T ) +10.03 350 SAGELE. 1.37(T ) 11.21  MPAG1  3 0 0  GMARSH GPLUM EUGAL  -2.99(T  350  2.72(T  3 5 Q  1 . 3 ' . 7 6 ( S t _ ) + 2.82  OSTRAG =  10  50  1 . 9 9 ( S t _ ) + 4.13  =  Q  1 0  ) + 30.25  ) - 21.27  -0.4-3(T ) + 4.4? 10  Salinity: GPAGI  -7-02(S  EUGA1  3.69(S  OSTRAG  3 5 0  ) + 220.24  3 5 Q  ) - 114.23  - 0 . 2 9 ( S ) + 11.40 1 0  THREE MONTHS OUT OF PHASE Temperature:  Stability:  GYPHOG  - 0 . 9 6 ( T ) + 9.^4  GYPHOG  0 . 9 6 ( S t _ ) + 0.63  EUPRIM  - 2 . 8 8 ( T ) +24.29  NANOM  1.29(st _ ) + l . o ( s t _ )  PMISTO  -3.19(T ) + 3 . 1 5 ( T  5Q  5Q  5Q  Salinity: GMARSH  0.57(S ) +18.99  3 0 Q  Q  10  0  -  )  10  5  2 6.69(St _ 7  5 0  2 0 0  3  3 1 . 0 7 ( S t _ ) + 1.65  CHIRTD  - 4 6 . 3 4 ( S t _ ) + 2.09  EUGAL  - 1 . 8 l ( S t _ ) + 1.44  1Q  PARTOT  50  1 0  0  5 0  )  GMARSH  1Q  1 0  5 Q  1 0  0.95(St _ ) 0  26.86(St _ )  1Q  :^ -i?(st 6  5 0  _  10  2 0 0  50  )  +8b9.4:2(st _ ) + 1.26 2  300  TOMSEP = - 0 . 6 6 ( S t _ ) - 2488.64(St _ ) 0  10  2  300  + 3.77 SAGELE = - 0 . 6 l ( S  V l 0  )  813.53(St _ 2  + 2.25 CONTINUED ON FOLLOWING PAGE...  3 0 Q  )  62  Table IX (Cont'd):  SIX MONTHS OUT OF PHASE Temperature:  Stability:  CYPHoc = - 0 . 6 6 ( T ) + 6.17  PMISTO = 3 5 - 7 7 ( S t _ ) - 4 8 1 . 4 ( S t _  5Q  SCLNA  = -8.48(T  3 0 Q  10  ) + 69-99  CMARSH = - 0 . 9 3 ( T ) - 4 . 9 1 ( T 5Q  = -2.03(T  5 0  SAGELE = - 0 . 8 1 ( S t _ ) + 1.44 Q  300  1 0  ) TOMSEP = - 2 . 1 7 ( S t _ ) + 1-56 Q  +52.05  1 0  OSTRAG 4= - 1 . 4 0 ( S t _ ) + 3-81 0  30Q  ) + 0.59(T  30Q  ) + 8.00(T  = 4.75(S  2 Q 0  ) - 144.54  SAGELE = - 7 . 9 8 ( S  3 0 Q  ) + 8.00(S  MPAG1  50  350  1 0  )PART0T = - 1 3 4 - 3 D ( ^ _ 5 Q  ) 2-22 +  2 Q Q  + 16.40 PARTOT = 2 . 3 4 ( T  350  )  Salinity: EUCAL  NB:  A l l e q u a t i o n s a r e o f t h e form:  3 5 Q  )  l n ( y + 0.01) = ax^ + bXg + c x + d x ^ 3  + ex^ + K where:  y i s t h e c o n c e n t r a t i o n o f t h e s p e c i e s (no./m ) 3  a,b,c,d,e a r e t h e c o e f f i c i e n t s o f t h e independent v a r i a b l e s x^,x^,x„,x^,x,, a r e t h e s u b d i v i s i o n s o f t h e independent v a r i a b l e 'x' K i s a constant A l l t e m p e r a t u r e s a r e i n °C a t t h e s u b s c r i p t e d d e p t h A l l s a l i n i t i e s are i n ° /  Q O  a t the subscripted depth  A l l s t a b i l i t i e s a r e i n u n i t s o f afa^+uS"^ over t h e subs c r i p t e d d e p t h range \ i? J I n t h i s and o t h e r t a b l e s , t h e d e p t h r a n g e s 200-300 m and 300-350 m a r e c o n c a t e n a t e d t o 2-300 m and 3~350 m r e s p e c t i v e l y f o r convenience.  2 0 Q  )  63  t h e m a j o r i t y (68%) of t h e s t a b i l i t y r e g r e s s i o n s i n v o l v e t h e t o p 50 m o f the water column.  A l s o , o n l y two s p e c i e s show s i m u l t a n e o u s s i g n i f i c a n t  r e g r e s s i o n s on t e m p e r a t u r e and  stability.  The m a j o r i t y of t h e s i g n i f i c a n t r e g r e s s i o n e q u a t i o n s i n v o l v e o n l y a c o n s t a n t and one independent v a r i a b l e of t h e f i v e t e s t e d s i m u l t a n e o u s l y . S t a b i l i t y t h r e e months out of phase produced t h e h i g h e s t number o f s i g n i f i c a n t r e g r e s s i o n s , f o l l o w e d by t e m p e r a t u r e s i x months out of phase,  and  t h e n by t e m p e r a t u r e i n phase. One p a r t i c u l a r l y i n t e r e s t i n g a s p e c t of t h e r e g r e s s i o n a n a l y s i s i s t h e r e l a t i o n s h i p between C a l a n u s plumchrus and C. m a r s h a l l a e .  The r e -  g r e s s i o n of t h e two s p e c i e s a g a i n s t t e m p e r a t u r e a t 350 m, a d e p t h a t which t h e r e i s c o n s i d e r a b l e o v e r l a p between t h e two p o p u l a t i o n s (see F i g . 10), y i e l d s r e g r e s s i o n l i n e s of o p p o s i t e s l o p e which i n t e r s e c t i n t h e r e g i o n o f normal ambient t e m p e r a t u r e ( F i g . 9)•  Factor analysis The i n i t i a l f a c t o r a n a l y s i s o f t h e p a r t i t i o n e d , t r a n s f o r m e d z o o p l a n k t o n d a t a produced e i g h t f a c t o r s which t o g e t h e r c o u l d y i e l d of t h e v a r i a n c e i n . t h e d a t a m a t r i x .  90%  A f t e r varimax r o t a t i o n , these f a c -  t o r s c o u l d a c c o u n t f o r v i r t u a l l y 100% o f t h e v a r i a n c e i n t h e m a t r i x . A l l o f t h e s p e c i e s w i t h h i g h p o s i t i v e l o a d i n g s on t h e f i r s t f a c t o r a r e deep water s p e c i e s t h a t a r e almost a b s e n t from n e a r s u r f a c e w a t e r .  The  t h r e e s p e c i e s w i t h t h e h i g h e s t n e g a t i v e l o a d i n g s on t h i s f a c t o r a r e s u r f a c e and s u r f a c e t o mid-depth s p e c i e s w i t h few r e p r e s e n t a t i v e s i n deep water.  The second f a c t o r i s a s s o c i a t e d w i t h s p e c i e s which have a mid-  d e p t h minimum and undergo some degree of v e r t i c a l m i g r a t i o n .  Factor  64a  F i g u r e 9:  R e g r e s s i o n of C a l a n u s plumchrus and 0. m a r s h a l l a e a g a i n s t t e m p e r a t u r e a t 350 m. Equations of the form: l n ( y + 0.01) = mx + b.  64b  ''8.6  87  88  8.9  9.0  9*1  92  T E M P E R A T U R E (°C)  93  9.4  95  96"  65  number t h r e e i s a s s o c i a t e d p r i m a r i l y w i t h s p e c i e s which a r e most h i g h l y concentrated  i n deep water b u t have a p p r e c i a b l e numbers a t mid-depths  and s m a l l numbers n e a r t h e s u r f a c e .  Factor four i s associated with  s p e c i e s which have a mid-depth maximum.  those  The o t h e r f a c t o r s a r e l e s s e a s i l y  a s s o c i a t e d w i t h s p e c i f i c groups o f s p e c i e s ; however, t h e s e f i r s t f o u r f a c t o r s can account f o r 73% o f t h e v a r i a n c e i n t h e z o o p l a n k t o n  matrix.  The o n l y l a r g e s p e c i e s group produced i n t h e i n i t i a l f a c t o r a n a l y sis  was t h e group o f 13 s p e c i e s a s s o c i a t e d w i t h t h e f i r s t f a c t o r .  To exa-  mine t h e s t r u c t u r e o f t h i s g r o u p i n g i n more d e t a i l , i t was t r e a t e d as a s e p a r a t e group o f s p e c i e s and r e - f a c t o r e d i n t h e same manner as t h e o r i g i nal  data block.  The seven f a c t o r s produced y i e l d e d 100% o f t h e v a r i a n c e  i n the zooplankton.  A f t e r r o t a t i o n , t h e y s t i l l reproduced  a l l of the  variance i n the zooplankton data, but t h e i r i n d i v i d u a l c o n t r i b u t i o n s t o t h e v a r i a n c e were more e q u i t a b l e .  The f i r s t f a c t o r was a s s o c i a t e d w i t h  s p e c i e s whose c o n c e n t r a t i o n was h i g h e s t i n deep water and t a p e r e d o f f t o wards t h e s u r f a c e .  The second f a c t o r was a s s o c i a t e d w i t h two o f t h e  s h a l l o w s p e c i e s , which had h i g h n e g a t i v e l o a d i n g s , and one deep water species.  The o t h e r f a c t o r s were a M o a s s o e i a t e d w i t h s i n g l e s p e c i e s .  The  r e s u l t s o f t h e f a c t o r i n g a r e shown i n T a b l e s X and X I .  P r i n c i p a l components a n a l y s i s The r e s u l t s o f t h e p r i n c i p a l components a n a l y s i s o f t h e h y d r o graphic data are given i n Table X I I .  S u f f i c i e n t e i g e n v a l u e s were e x t r a c t e d  i n each case t o y i e l d a t l e a s t 95% o f t h e v a r i a n c e o f t h e d a t a m a t r i x .  The  r e m a i n i n g v a r i a n c e was l o s t i n t r u n c a t i n g t h e number o f e i g e n v a l u e s under consideration.  Truncated  e i g e n v a l u e s i n d i v i d u a l l y accounted f o r an  Table Xt  I n i t i a l f a c t o r i n g of zooplankton data  VARIMAX FACTOR LOADINGS Species Acronym:  Factor: 1  CPLUM  0.97  0.08  0.01  0.08  0.08  -0.10  0.01  O.05  PSEUDO  0.9?  0.0?  -0.03  -0.13  0.04  -0.14  . 0.01  -0.06  MPAC1  0.97  -0.04  0.12  0.04  0.13  0.04  0.11  -0.02  EUCAL  0.94  -0.08  0.20  0.11  -0.16  0.02  -0.11  -0.10  METOK  0.8? .  0.10  0.14  -0.25  0.24  0.08  -0.01  -0.02  CMARSH  0.79  O.58  -0.03  -0.12  O.07  -0.08  -0.01  -0.02  SCINA  0.78  0.22  -O.52  -0.15  -0.04  0.15  0.05  -0.05  OTHOC  0.65  -0.17  -0.24  0.19  -0.09 "  0.35  0.26  -0.49  CP AC I  0.61  0.35  -0.25  -0.06  0.29  -0.25  0.05  0.21  CANDAC  0.52  -0.39  -0.12  0.26  0.48  0.06  0.03  0.06  ACARLO  -0.69  -0.43  -0.05  -O.34  0.29  0.33  . -0.02  0.16  HUGGIA  -0.73  0.05  -0.39  -0.41  -0.22  0.11  0.00  -0.27  AEG IN A  -0.81  0.00  0.01  -0.05  0.26  0.1?  0.0?  -0.03  0.22 .  -0.15  0.05  -0.24 O.36  OIKOP  ** ****** -0.14  2  * * X ** -  3  4  5  XXX  -0.68  6  7  -0.25  0.02  8  0.10  PARTOT  -0.45  -0.70  -0.29  0.00  -0.03  EUPAC  -0.11  -0.75  -0.03  0.18  0.07  -0.08  PARI  -0.25 .  -0.75  -0.35  0.16  -0.15  -0.06  0.18  -0.11  SAGELE  0.40  -0.86  0.04  0.05  0.13  0.02  0.11  0.12  MEDSPA  0.18  0.00  -0.53  0.23  0.44  -0.26  -0.13  0.22  OSTRAC  0.02  -0.31  -0.61  -0.47.  0.34  -0.18  -0.01 .  0.11  PMISTO  -0.48  9.06  -0.82  -0.04  -0.13  0.25  0.10  -0.04  -0.95  -0.21  0.05  -0.15  GAIDCO  -0.26  0.48  -0.10  -0.65  -0.14  -0.12  0.42  0.13  TOMSEP  0.18  0.23  0.02  -0.79  0.32  0.03  -0.14  0.29  OSPIN  0.00  0.01  -0.27  -0.88  0.05  -0.11  -0.37  -0.09  HPAC2  -0.10  -0.08  -0.03  0.90  -0.02  -0.13  -0.03  PAR2  -0.10  0.16  O.I?  * ¥. -y.-x -0.0?  0.92  0.06  0.08  -0.09  -0.26  LIMAC  EUPRTM AEQUOR CLLIM CHIRID NAN 014  ********  ******** -0.25 0.05  -0.05  -0.15  -0.2?  -0.06  -0.0?  -0.16  0.03  -0.15  -0.42  0.20  0.08  0.60  O.38  0.23  -0.04  -0.16  0.39  -0.23  -0.57  -0.19  -0.24  -0.43  -0.10  0.20  0.11  -0.30  0.55  0.20  .0.11  -0.30  ******** 0.55  0.0?  0.00  7.0  7.0  . -0.5'+  -0.29  -0.24  -0.43  -0.10  -0.10  0.58  0.00  0.12  % of zooplankton v a r i a n c e accounted f o r by each factor: 3^.0  16.0  13.0  10.0  0.14  0.03  -O.78 **#-M~X-**-*  6.0  6.0  67  Table XI: Secondary factoring of species associated with the f i r s t factor of Table X.  Species Acronym:  Factor: 1  VARIMAX FACTOR LOADINGS 2  3  4  .5  6  -  7 '  CPAGI  0.91.  0.09  0.00  -0.25  -0.05  0.C9  0.01  SCINA  0.73  0.32  -0.46  0.20  -0.18  0.14  -0.14  CMARSH  0.73  0.44  -0.15  -0.19  0.03  0.23  -0.16  CPLUM  0.59  0.44  -0.26  -0.39  -0.29  0.21  -0.34  PSEUDO  0.57  0.48  -0.28  -0.21  -0.25  O.30  -O.36  MPAC1  0.49 ******** 0.25  0.35  -0.33  -0.42  -0.34  0.31  -0.35  -O.38  -0.22  0.31  -0.47  -0.14  -0.01  -0.05  0.22  -0.17  0.16  -0.20  0.11  -0.08  EUCAL ACARLO  -0.33  AEGINA  -0.26  CYPHOC MUGGIA CANDAC METOK  ******** 0.52 -0.75  -0.38  .  0.24  0.51  0.15  0.12  -O.90 ******** 0.19-  ******** -0.94  -0.23  -0.32  ******** 0.02  0.07  0.08  -0.21  0.55  0.23  -0.22  0.15  % of zooplankton variance accounted f o r by each factor: . 27.1  -0.09 ******** 0.79 ******** -0.18 -0.23  0.41 -0.18 ******** 0.10 -0.93 ******** . ******** O.69 -0.22  ********  21.3  13-3  12.2  7.6  5.6  0.13 -0.07 -0.14  T a b l e X I I : P r i n c i p a l components o f t h e h y d r o g r a p h i c d a t a .  VARIABLE Temperature  EIGENVALUES  % OF TOTAL VARIANCE  CUMULATIVE % VARIANCE  SUBDIVISIONS  1  EIGENVECTORS 2 3  2.64  53  53  T  0.04  -0.71  -0.58  1.34  27  80  0.15  -0.69  0.55  0.85  18  98  T 50 T 200 T T300  0.53  0.05  0.47  0.60  0.05  -0.22  0.58  0.13  -0.31  0.26  -0.87  -0.20  0.48 0.48 0.48  -0.26  0.37  0.22  0.65  0.29  -0.44  0.49  0.21  -0.46  0.50  -0.31  -O.56  -0.13  0.68  -0.071.  -0.12  0.11  •0.49  0.11  0.70  0.32  0.02  0.66  -0.43  0.62  0.23  O.67  -0.03  -0.70  350 Salinity  Stability  3.80  76  76  S  10  0.97  19  94  s  0.16  50  4  98  S  200  S  300  S  350  1.96  39  39  s t  1.73  35  74  s t  0.93  18  92  0.22  97  oio.  50 St 200-300 St 300-350  s t  69  i n s i g n i f i c a n t amount o f t h e v a r i a n c e i n t h e parameter. The f i r s t t h r e e o f f i v e p r i n c i p a l components o f t e m p e r a t u r e g e n e r a t e 98% o f t h e v a r i a n c e .  The f i r s t component has h i g h n e g a t i v e l o a d i n g s on  deep water d a t a and n e g l i g i b l e l o a d i n g s on n e a r s u r f a c e water.  The  second component has h i g h n e g a t i v e l o a d i n g s on n e a r s u r f a c e water and n e g l i g i b l e l o a d i n g s on deep water t e m p e r a t u r e s  F a c t o r three has a h i g h  n e g a t i v e l o a d i n g on T ^ Q , and h i g h p o s i t i v e l o a d i n g s on T^Q and Tgoo* S a l i n i t y a l s o has t h r e e major components.  The f i r s t component r e -  l a t e s most s t r o n g l y t o deep and i n t e r m e d i a t e w a t e r .  The second component  has a s i n g l e h i g h n e g a t i v e l o a d i n g on t h e s h a l l o w e s t depth and t h e t h i r d component has a s i n g l e h i g h p o s i t i v e l o a d i n g on i n t e r m e d i a t e water w i t h two l e s s e r n e g a t i v e l o a d i n g s on deep water. S t a b i l i t y components show l e s s redundancy.  A l l f i v e are required  t o y i e l d lOQ&oof t h e v a r i a n c e i n t h e s t a b i l i t y m a t r i x . however, y i e l d <J]% o f t h e v a r i a n c e .  The f i r s t f o u r ,  The f i r s t t h r e e can be a s s o c i a t e d  w i t h n e a r s u r f a c e , deep and i n t e r m e d i a t e water r e s p e c t i v e l y . has a h i g h p o s i t i v e l o a d i n g on StgQQ -^QQ> St  The f o u r t h  a h i g h n e g a t i v e l o a d i n g on  300-350"  The r e s o l u t i o n o f t h e p r i n c i p a l components o f each o f t e m p e r a t u r e , s a l i n i t y and s t a b i l i t y i n t o t h r e e d e p t h r e l a t e d g r o u p i n g s i s r e l a t e d t o t h e d i v i s i o n o f t h e water column a t Geo 1748 i n t o t h r e e d i s t i n c t r e g i o n s . Thus t h e major o r i e n t a t i o n o f t h e p r i n c i p a l components i s r e l a t e d t o t h e p h y s i c a l s t r u c t u r e o f t h e water column.  The r a n k o r d e r i n g o f t h e s t a n -  d a r d i z e d cases on h y d r o g r a p h i c d a t a components ( T a b l e X I I I ) s u g g e s t s i n a d d i t i o n t h e p r e s e n c e o f a t e m p o r a l b i a s i n t h e components. t i c u l a r l y t r u e o f t h e f i r s t component o f t e m p e r a t u r e .  This i s par-  L a t e r months have  70  Table XIIIi  Rank order of standardized cases on each principal component.  HYDRODATA COMPONENTS  jSt  Temperature  8 7 11 6 10 1 9 3 2 5 4  2  n d  5 11 7 10 3 9 8 2 4 1 6  Salinity  3  6 10 4 7 3 9 5 11 2 8 1  2  2 1  2 11  3 7 6 8  9 4 10  2  3c 10c  lb 10b lib  5c 2c 4c 3b 6c 10b 9b 7b lb 8b lib 5b 2b 4b 6b 3a 10a 9a 7a la lla 8a 5a 4a 2a 6a  3  l  r d  6 10 4 2  3 8 6  2  4 6  3  r d  7 2 6 4  7 6 9 3 1 2 11 4  3 11 1 2  9 5  nd 8  7 5 9 10 8  7 3 8 11 1  5 7 1  3 t  9 1 5 3 11 8 10  5 10  k  th 4  5 2 8 10 7 1 9 6 3 11  ZOOPLANKTON COMPONENTS  ^st  11c  Stability  nd  5 9 4 10 11  9c 7c lc 8c  Month Codeoi  jSt  r d  n d  3b 5b 9b 2b 8b 7b 4b 6b la lc 10a 10c lla 3a 5a 11c 2a 9a 3c 5c 2c 9c 8a 8c 7a 7c 4a 6a 4c 6c  3  r d  k  th  5  t h  7a 7b 7c 3a 8b 10a  3a 3b 3c 10a 4a 10b  ?b 7c 7a 4b  8c 10b 10c lla lib 11c  10c 9a 5a 4b lla 4c  4a 4c 3a 3c 8a 8c  9a 9b 9c 5a 6a  ?a 9c 9b la  5b 2b lb 2c 6b lc  5b 5c 6b 6c la lb lc 3a 3b 3c 4a 4b 4c 2a 2b 2c  5c lie 5b lib 7c 7b lb lc 6a 8a 2a 6c 6b 8b 8c 2c 2b Doc 71 10 » Dec 72 11 -  1 - Oct 69 2 - Nov 69  4 - Nov 70 5 - Dec ?0  78 -  3 - Dec 69  6 - Nov 71  9 - Hov ?3  3b 8b  5c 2a 5a la 6c 6a lib 9b lla 10b 11c 9c 9a 10c 10a Dec 73 Dec 74  6  th  7  6b 6c 6a 3b 3c 3a  8c 8a 8b 11c lib  9b lib 7b 4b 2b 9a 9c lla 11c 10b  t h  10a lla 10c 2a 3a 2c 10b 2b  ?c 7a 8b 4a 2c 2a 4c 10c 10a 8c lb 8a la lc  3b 3c 4a 4a 4b 4c 5a 5b 5c la ?a 6a lc 7c 6c 7b lb  5b 5a  9a 9c 9b 5c Depth Codesi  NBi If no dopth code Is given, the month code rofers to the whole water column  a - 0-75 m b - 75-200 m c - 200-390 m  71  h i g h r a n k i n g s on t h i s component, w h i l e e a r l y months have low r a n k i n g s . In a d d i t i o n , t e m p e r a t u r e s a t d e p t h s g r e a t e r than 200 m have t h e h i g h e s t l o a d i n g s on t h e f i r s t t e m p e r a t u r e component, s u g g e s t i n g t h a t t h e tempora l b i a s i s a f u n c t i o n o f deep water r a t h e r than o f n e a r s u r f a c e water. A t e m p o r a l b i a s a l s o shows up i n t h e s a l i n i t y d a t a , a l t h o u g h t o a l e s ser  e x t e n t , b u t t h e case r a n k i n g s o f t h e s t a b i l i t y components a r e n o t  sequential. The f i r s t seven e i g e n v e c t o r s o f t h e z o o p l a n k t o n  core species matrix  y i e l d 94% o f t h e v a r i a n c e o f t h e m a t r i x ( T a b l e X I V ) .  Of t h e seven, o n l y  t h r e e account i n d i v i d u a l l y f o r more than 10% o f t h e v a r i a n c e , t h e l a r g e s t accounting f o r  J&fo.  I n many r e s p e c t s , t h e r e s u l t s a r e s i m i l a r t o t h o s e  seen i n t h e f a c t o r a n a l y s i s ( T a b l e s X, X i ) . The f i r s t t h r e e components generated  appear t o have s p e c i e s a s s o c i a t i o n s s i m i l a r t o t h e a s s o c i a t i o n s  w i t h t h e f i r s t t h r e e f a c t o r s generated,  although t h e absolute values of  the c o e f f i c i e n t s of t h e eigenvectors a r e g e n e r a l l y lower i n the p r i n c i p a l components a n a l y s i s . zooplankton  The f i r s t t h r e e f a c t o r s account f o r over 60% o f t h e  variance i n both  analyses.  The s p e c i e s / e i g e n v e c t o r a s s o c i a t i o n s o f t h e two a n a l y s e s after the t h i r d factor i s extracted. to  diverge  T h i s d i v e r g e n c e may be due i n p a r t  t h e r e d u c t i o n o f t h e s p e c i e s m a t r i x t o twenty c o r e s p e c i e s i n t h e p r i n -  c i p a l components a n a l y s i s . The f o u r t h p r i n c i p a l component has h i g h negat i v e l o a d i n g s on t h e t h r e e amphipod s p e c i e s ( C y p h o c a r i s Euprimno a b y s s a l i s and P a r a t h e m i s t o e l o n g a t a (PAR2). pacifica.  challengeri,  p a c i f i c a ) and on j u v e n i l e P a r e u c h a e t a  The h i g h e s t p o s i t i v e l o a d i n g i s 0.25,  w i t h Euphausia  Component number f i v e has h i g h n e g a t i v e c o e f f i c i e n t s w i t h  s p e c i e s t h a t have a n e a r s u r f a c e minimum and a mid-depth maximum, b u t  72  T a b l e XIV: P r i n c i p a l components a n a l y s i s o f t h e p a r t i t i o n e d z o o p l a n k t o n data.  Eigenvalues  P e r cent o f t o t a l variance  C u m u l a t i v e p e r cent of v a r i a n c e .  7.21  36  36  3.80  19  55  2.99 1.70  15  70  9 6  79  5 4  90  1.24  1.01 0.89  Species——  8594  :  EUPAC  1  2  3  4  5  6  7  -0.14  -0.37  -0.07  00003  -0.11  0.03  -0.30  -0.27  0.27  -0.49  0.02  T0MSEP  0.12  SAGELE  0.03  -0.41  -0.17  0.13  -0.21  CYPH0C  0.13  -O.36  0.09  -0.42  -0.01  0.12  -0.01  EUPRIM  -0.27  -0.06  0.01  -0.45  -0.01  0.15  -0.09  PMIST0  -0.23  0.06  -0.16  -0.46  MEBSPA  00006  0.00  -0.37  -0.05  NAN0M  -0.13  CHIRID  -0/16  0.24  -0.39  0.08  0.28  -0.31  -0.01  0.21 0.10  0.14  -0.33  0.03  -0.65  0.08  -0.02  0.48  -0.08  -0.13  0.11  -O.36  -0.04  -0.49  -0.32  0.13  -0.02  0.09  -0.02  -0.19  CPLUM  0.35 0.34  -0.15  -0.07  -0.10  -0.01  -0.10  -0.06  EUCAL  0.31  -0.23  -0.06  -0.07  -0.16  -0.09  MPAC1  0.33  -0.22  -0.04  -0.07  -0.09  -0.03  MP AG 2  -0.02  0.05  -0.37  0.07  -0.35  0.52  0.34  -0.15  -0.08  -0.08  -0.03  -0.01  0.02  PARI  -0022  -0.34  -0.13  -0.17  0.29  PAR2  -0.07  0.08  0.23  -0.45  -0.13  -0.21  0.27  0.07  -0.27  -0.15  0.21  0.05  0.17  OSTRAC  -0.04  -0.06  -0.52  -0.09  CO. 00  0.08  0.33  PARTOT  -0.30  -0.25  -0.09  -0.13  -0.18  0.10  0.11  CMARSH  PSEUD0  GPACI  '  0.10  0.02  0.06  0.20 -0.50  0.02 -0.12  73  this relationship have n e g l i g i b l e  i s n o t c o n s i s t e n t , as some s p e c i e s showing t h i s p a t t e r n  coefficients.  The r e m a i n i n g  e i g e n v e c t o r s can n o t r e a d i l y  be a s s o c i a t e d w i t h any d e f i n i t e s p e c i e s group,.' The r a n k o r d e r i n g o f cases on p r i n c i p a l components ( T a b l e X l l l ) r e i t e r a t e s t h e d i v i s i o n o f t h e water column i n t o t h r e e r e g i o n s .  A l l of the  deep water cases have h i g h r a n k i n g s on t h e f i r s t component, w h i l e t h e n e a r s u r f a c e cases have t h e l o w e s t r a n k i n g s .  F o r component two, i n t e r -  mediate water has t h e h i g h e s t r a n k i n g s , w i t h a t r e n d i n t h e r e m a i n i n g r a n k i n g s f o r November and December d a t a t o be ranked w i t h November cases ranked  lowest.  i n separate blocks,  The r a n k s of t h e s t a n d a r d i z e d  on component t h r e e a r e t e m p o r a l l y a r r a y e d . r a n k s h i g h e s t on t h e f o u r t h component.  cases  December 196-9, a l l d e p t h s ,  December 1971, a l l d e p t h s , has t h e  t h r e e h i g h e s t r a n k i n g s on component f i v e , w h i l e t h e f i n a l t h r e e months sampled monopolize t h e l o w e s t r a n k s .  Components s i x and seven a r e s i m i -  l a r l y a s s o c i a t e d w i t h s p e c i f i c months: November 1971 and December respectively.  1972  74  Discussion Data  manipulation Over 75 groups o r s p e c i e s o f z o o p l a n k t o n were i d e n t i f i e d i n t h e  samples; however, many a r e o n l y • p e r i p h e r a l members o f t h e z o o p l a n k t o n community.,, iii:-.that.. t h e i r : c o n t r i b u t i o n t o t h e community biomass i s v e r y s m a l l , a, L  and  several are present  i n small numberssldifficultttoa.assessaacc.urately  w i t h a v a i l a b l e s a m p l i n g methods.  The e l i m i n a t i o n o f such s p e c i e s i n  o r d e r t o r e d u c e background n o i s e i n d a t a a n a l y s i s i s a c c e p t e d p r a c t i c e . A n g e l and Fasham (1973) chose o n l y 50 o f 212 i d e n t i f i e d copepod s p e c i e s , 8 o f 84 i d e n t i f i e d amphipod s p e c i e s and 13 o f 16 i d e n t i f i e d  chaetognath  s p e c i e s f o r f a c t o r a n a l y s i s o f d i f f e r e n t segments o f t h e SOND C r u i s e z o o a , plankton data.  The e l i m i n a t e d s p e c i e s were n o t c o n s i d e r e d  in sufficientlnumbers for "useful analysis". Michael  t o be p r e s e n t  S i m i l a r l y , C a s s i e and  (1968) f o u n d o n l y 12 s p e c i e s i n s u f f i c i e n t abundance f o r numeri-  c a l a n a l y s i s , and reduced t h i s number t o 8 s p e c i e s f o r c a n o n i c a l c o r r e l a t i o n a n a l y s i s w i t h sediment p r o p e r t i e s a t 21 s t a t i o n s . G r i e g - S m i t h (1971) has d i s c u s s e d t h e r a t i o n a l e b e h i n d t h e e l i m i n a - - ; t i o n of selected data p r i o r t o a n a l y s i s .  He s u g g e s t s t h a t o f t e n a l a r g e  p r o p o r t i o n o f t h e d a t a i s e s s e n t i a l l y background n o i s e .  Even though  .this n o i s e may c o n t a i n m e a n i n g f u l i n f o r m a t i o n , i t might s t i l l be d e s i r able t o eliminate i t f o r p r a c t i c a l reasons.  The d e g r e e t o which a com-  p l e x d a t a bank can s a f e l y be r e d u c e d can o n l y be a r r i v e d a t e m p i r i c a l l y , but t h e r e i s an i n d i c a t i o n t h a t 10-20% o f t h e o r i g i n a l d a t a may be s u f f i c i e n t i n some c a s e s ( e . g . A s h t o n 1964, c i t e d i n G r i e g - S m i t h 1971; A u s t i n and G r i e g - S m i t h I968). A l t h o u g h I e l i m i n a t e d s e v e r a l s p e c i e s , many o t h e r a p p a r e n t l y  minor  75  z o o p l a n k t o n s p e c i e s were r e t a i n e d f o r a n a l y s i s .  Species present i n low  but m e a n i n g f u l numbers may s t i l l be good i n d i c a t o r s o f s u b t l e f l u c t u a t i o n s w i t h i n t h e community. L e w i s e t a l . (1971, 1972) of E u c h a e t a  F o r example, L e w i s and Ramnarine ( l 6 ° ) and Q  have shown t h a t t h e e a r l y d e v e l o p m e n t a l  stages  j a p o n i c a ( = P a r e u c h a e t a e l o n g a t a i n my a n a l y s i s ) a a r e s e n s i -  t i v e t o i n t e r a c t i o n s of t r a c e metals w i t h types of d i s s o l v e d organic s u b s t a n c e s i n sea .water.  F i e l d p o p u l a t i o n s o f P. e l o n g a t a may r e a c t t o  changes i n t h e s e agents sooner than such d i f f e r e n c e s can r e a d i l y be measured.  Other s p e c i e s p r o b a b l y r e a c t s i m i l a r l y t o t r a c e m e t a l / o r g a n i c  i n t e r a c t i o n s and t o o t h e r f a c t o r s which i n f l u e n c e "water q u a l i t y " .  Reac-  t i o n s o f i s o l a t e d s p e c i e s can t h u s be i m p o r t a n t as t h e y might i n d i c a t e a change t h a t w i l l e v e n t u a l l y a f f e c t t h e whole community. I t i s c o n s e q u e n t l y b e t t e r t o e r r on t h e s i d e o f r e t a i n i n g more s p e c i e s than n e c e s s a r y than on t h a t o f d i s r e g a r d i n g p o s s i b l y species.  important  The s p e c i e s which were d i s r e g a r d e d a t t h i s i n i t i a l s t a g e o f t h e  d a t a m a n i p u l a t i o n were p r e s e n t i n such l o w numbers a s t o be o f l i t t l e value f o r s t a t i s t i c a l parameters.  comparison  with other species or with p h y s i c a l  As a r e s u l t , t h e community a s d e s c r i b e d i n t h i s t h e s i s can  be c o n s i d e r e d t o c o n s i s t o f a b l o c k o f 29 groups f o r which r e l i a b l e d a t a c o u l d be o b t a i n e d .  T h i s l i s t can be f u r t h e r reduced t o t h e c o r e s p e c i e s  l i s t i f i t i s d e s i r e d t o examine e i t h e r t r e n d s known t o be common t o t h e whole community o r t r e n d s w i t h i n major s p e c i e s .  D i v e r s i t y and m u l t i p l e c o r r e l a t i o n  analysis  I t i s p r e f e r a b l e t o r e t a i n t h e maximum number o f s p e c i e s i n t h e i n i t i a l s t a g e s o f a n a l y s i s i f t h e i n t e n t o f t h e i n i t i a l methods i s t o  76  o b t a i n an overview method.  of the community.  D i v e r s i t y i s such an  analytical  I t i s s e n s i t i v e t o b o t h t h e number o f s p e c i e s and t h e number o f  i n d i v i d u a l s , and c o n s e q u e n t l y  the b e s t e s t i m a t e o f d i v e r s i t y w i l l  be  based n o t on a reduced d a t a b l o c k , b u t on a b l o c k o f as many s p e c i e s as possible.  On t h i s b a s i s , t h e d i v e r s i t y of t h e o v e r w i n t e r i n g  community o f t h e S t r a i t of G e o r g i a was period.  zooplankton  almost c o n s t a n t w i t h i n t h e  S i n c e d i v e r s i t y i s not a s p e c i e s s p e c i f i c measurement, an  p a r e n t constancy  sampling ap-  i n d i v e r s i t y does not i m p l y a l a c k o f change i n e i t h e r  the species composition  o f the t o t a l p o p u l a t i o n of the community.  It  does suggest, however, t h a t any changes which have o c c u r r e d have tended to  o f f s e t each o t h e r , w i t h no t r e n d towards more o r fewer s p e c i e s , o r  towards h i g h e r o r l o w e r a c t u a l numbers. The  c o r r e l a t i o n m a t r i x a l s o s u g g e s t s a r e l a t i v e l y s t a b l e community,  and s u p p o r t s t h e i m p l i c i t assumption t h a t t h e z o o p l a n k t o n which I am d e a l i n g may  be c a l l e d a community.  assemblage w i t h  The predominance of p o s i -  t i v e c o r r e l a t i o n c o e f f i c i e n t s suggests a f a i r l y c l o s e l y k n i t group of organisms, b u t t h e r e a r e few s t r i k i n g r e l a t i o n s h i p s w i t h i n t h e m a t r i x . The most o b v i o u s f e a t u r e i s t h e c l o s e n e s s of t h e r e l a t i o n s h i p s among t h e amphipod s p e c i e s .  Each s p e c i e s i s p o s i t i v e l y c o r r e l a t e d w i t h t h e o t h e r s ,  and t h u s t h e i r p o p u l a t i o n * f l u c t u a t i o n s may ,  be r e g u l a t e d by f a c t o r s which  a f f e c t c h a r a c t e r i s t i c s common t o a l l members o f t h e group.  There i s no  immediate i n d i c a t i o n o f what t h e s e f a c t o r s might be; however, f e e d i n g h a b i t s a r e u n l i k e l y t o be d i r e c t l y i n v o l v e d .  Euprimno a b y s s a l i s . i s  equipped f o r r a p t o r i a l f e e d i n g w h i l e t h e o t h e r s p e c i e s a r e equipped f o r f i l t e r feeding.  S i m i l a r l y , the v e r t i c a l d i s t r i b u t i o n p a t t e r n s of the  species are d i f f e r e n t .  77  A s i d e from e s t a b l i s h i n g t h e i n t e r c o r r e l a t i o n between amphipod species,  t h e c o r r e l a t i o n a n a l y s i s does n o t g i v e much i n s i g h t i n t o t h e  s t r u c t u r e o f t h e z o o p l a n k t o n community.  I t would be more u s e f u l t o com-  p a r e t h e c o r r e l a t i o n s t r u c t u r e o f t h e community over d i f f e r e n t t i m e periods.  T h i s would r e q u i r e a c q u i s i t i o n o f enough d a t a t o g e n e r a t e a  s e r i e s o f c o r r e l a t i o n matrices,of t h e s p e c i e s  each r e p r e s e n t i n g  over a f o u r o r f i v e y e a r p e r i o d .  the intercorrelations I f these two-dimensional  m a t r i c e s were a r r a n g e d a l o n g a temporal!'.axis, t h e y would form a t h r e e d i m e n s i o n a l m a t r i x amenable t o m u l t i v a r i a t e a n a l y s i s .  The number and  d e g r e e o f s i g n i f i c a n t c o r r e l a t i o n s s h o u l d change a s t h e s p e c i e s v e r g e d towards o r d i v e r g e d from a more d i v e r s e community.  con-  I t might be  p o s s i b l e t o d i s c o v e r t r e n d s i n t h e c o r r e l a t i o n s t r u c t u r e t h a t would be i n d i c a t i v e o f s u b t l e s h i f t s i n t h e community s t r u c t u r e .  The c u r r e n t l y  a v a i l a b l e data are not s u f f i c i e n t t o further explore t h i s p o s s i b i l i t y .  Cluster  analysis  C l u s t e r a n a l y s i s generates the f i r s t concrete p i c t u r e of the s t r u c t u r e o f t h e z o o p l a n k t o n community.  The c l u s t e r s w i t h i n which t h e  p a r t i t i o n e d months f a l l a r e s t r o n g l y a s s o c i a t e d The  with the p a r t i t i o n i n g .  c l o s e s t a s s o c i a t i o n s a r e w i t h i n r e g i o n s o f t h e x w a t e r column.  example, n e a r s u r f a c e  samples a r e c l u s t e r e d t o g e t h e r r a t h e r t h a n samples  f r o m t h e whole water column t a k e n i n t h e same month. t e r n of association  For  suggests that s p a t i a l separation  Although t h i s pati s more i m p o r t a n t i n  d e t e r m i n i n g r e l a t i o n s h i p s than i s t e m p o r a l s e p a r a t i o n ,  i t i s l a r g e l y the  r e s u l t o f t h e a r t i f i c i a l p a r t i t i o n i n g o f t h e water column.  Relationships  w i t h i n each o f t h e t h r e e groups a r e more l i k e l y t o r e f l e c t t h e p r e s e n c e  78  of t e m p o r a l t r e n d s i n t h e z o o p l a n k t o n tioning.  and t o be u n a f f e c t e d by t h e p a r t i -  The s e g r e g a t i o n o f t h e deep water samples i s a p p a r e n t l y based  on t h e f a c t t h a t t h e y a r e t e m p o r a l l y s e p a r a t e d .  There i s a group w i t h i n  the deep water c l u s t e r , and s e p a r a b l e a t a s i m i l a r i t y l e v e l o f t h a t c o n t a i n s a l l of t h e samples taken a f t e r November 1971•  O.63,  October and  December I969 f o r m a second d i s c r e t e group a t t h i s l e v e l , w h i l e t h e r e mainder of the samples form a t h i r d group. Although the temporal groupings  o f t h e i n t e r m e d i a t e water d a t a  are  l e s s d i s t i n c t , t h e l a s t t h r e e i n t e r m e d i a t e water samples t a k e n d u r i n g t h e s u r v e y a r e grouped, as a r e s i x o f t h e f i r s t e i g h t samples. f a c e water t h e r e i s a l s o e v i d e n c e o f t e m p o r a l November and December 1971 December 1973  and 1974  separation w i t h i n the data.  a r e c l u s t e r e d w i t h December 1972.  a r e grouped w i t h November 1973;  I969 i s a l s o c l u s t e r e d w i t h t h i s group. these groupings  In near sur-  In a d d i t i o n ,  however, November  The g e n e r a l i n d i c a t i o n f r o m  i s t h a t r e c e n t deep water samples a r e s e p a r a b l e f r o m  e a r l i e r samples, and t h a t t o a l e s s e r e x t e n t i n t e r m e d i a t e and n e a r s u r f a c e samples may  be s i m i l a r l y  separable.  There i s a l s o an i n d i c a t i o n t h a t g r o u p i n g of s i m i l a r months o c c u r s f o r i n t e r m e d i a t e and deep water samples. f r o m November 1969,  1970  and 1971  t h r e e samples i n deep water.  I n t e r m e d i a t e d e p t h samples  a r e grouped, as a r e t h e  corresponding  This grouping probably r e f l e c t s a r e a l  s i t u a t i o n , as November and December r e p r e s e n t s l i g h t l y d i f f e r e n t p o i n t s i n t h e a n n u a l c y c l e o f t h e community.  The f a c t t h a t t h i s shows up i n  the c l u s t e r i n g process supports the a b i l i t y of c l u s t e r a n a l y s i s t o d i s criminate associations within a data set. C l u s t e r i n g o f s p e c i e s a i s o produces groups t h a t a r e d i s t r i b u t i o n  79  o r i e n t e d r a t h e r than t i m e o r i e n t e d . t i c u l a r l y d i s t i n c t group. t i o n patterns  The deep water s p e c i e s form a p a r -  S p e c i e s which have u n u s u a l v e r t i c a l d i s t r i b u -  (e.g. A c a r t i a longiremus, which i s the only d i s t i n c t near  s u r f a c e s p e c i e s , and A e g i n a sp., t h e o n l y o t h e r s p e c i e s absent from deep w a t e r ) do not f i t i n w i t h any  cluster.  Species c l u s t e r s are a l s o p a r t l y  r e l a t e d t o t h e p a r t i t i o n i n g of the d a t a ; however, s i n c e t h e p a r t i t i o n i n g r e f l e c t s the a c t u a l v e r t i c a l d i s t r i b u t i o n p a t t e r n s  of t h e s p e c i e s ,  the  c l u s t e r i n g i s as i n d i c a t i v e of the s t r e n g t h of the d i s t r i b u t i o n a l  associa-  t i o n s as i t i s of t h e p a r t i t i o n i n g method. C l u s t e r a n a l y s i s s u g g e s t s t h a t the community i s h i g h l y The  s p a t i a l arrangement of t h e s p e c i e s  i s apparently  structured.  more i m p o r t a n t than  a r e t e m p o r a l changes i n community s t r u c t u r e , and t h e r e has been no a l s h i f t of s u f f i c i e n t i n t e n s i t y t o d i s r u p t t h e b a s i c p a t t e r n of  temporthe  community.  Canonical  correlation analysis  C l u s t e r a n a l y s i s i n d i c a t e s t h e i m p o r t a n c e t o t h e community of the v e r t i c a l d i s t r i b u t i o n o f s p e c i e s w i t h i n t h e water column.  The  effect  of t h e h y d r o g r a p h i c regime on s p e c i e s grouped by t h i s c r i t e r i o n can c l a r i f i e d by c a n o n i c a l t u r e and  correlation analysis.  The  be  i m p o r t a n c e of tempera^,  s t a b i l i t y f a c t o r s i n t h i s a n a l y s i s i s i n t r i g u i n g . Only 5 of  s i g n i f i c a n t c a n o n i c a l a c o r r e l a t i o n s a r e w i t h s a l i n i t y , and none of s a l i n i t y f a c t o r s can account f o r g r e a t e r t h a n 34% zooplankton variance. important.  The  of the  24  the  corresponding  Temperature, however, appears t o be p a r t i c u l a r l y  most o b v i o u s t e m p e r a t u r e e f f e c t i s on C a l a n u s m a r s h a l l a e .  I t appears t h a t t h e o v e r w i n t e r i n g  population  of t h i s s p e c i e s i s a s s o c i a t e d  80  w i t h o r a f f e c t e d by t e m p e r a t u r e v a r i a t i o n a t a l l t i m e s o f t h e y e a r , w i t h a t l e a s t 79% of t h e z o o p l a n k t o n v a r i a n c e e x p r e s s e d i n t h e a p p r o p r i a t e temperature f a c t o r .  Group 1 ( E u p h a u s i a p a c i f i c a , Nanomia b i j u g a ,  Pareu-  c h a e t a e l o n g a t a ( t o t a l and mature), and S a g i t t a e l e g a n s ) i s a l s o a f f e c t e d by t e m p e r a t u r e t h r o u g h o u t t h e y e a r and by s a l i n i t y and s t a b i l i t y a t c e r t a i n t i m e s as w e l l ; however, t h e amount o f z o o p l a n k t o n v a r i a n c e t h a t i s e x p r e s s e d i n t h e a p p r o p r i a t e h y d r o g r a p h i c f a c t o r i s low, n e v e r  exceeding  27%.  The phase r e l a t i o n s h i p s between z o o p l a n k t o n and h y d r o g r a p h i c p a r a meters u n d e r l i n e t h e r o l e o f t h e h y d r o g r a p h i c regime i n d e t e r m i n i n g t h e s i z e o f t h e o v e r w i n t e r M g p o p u l a t i o n s o f many z o o p l a n k t o n s p e c i e s .  The  importance o f h y d r o g r a p h i c c o n d i t i o n s i n t h i s r e s p e c t i s n o t u n u s u a l , b u t h y d r o g r a p h i c c o n d i t i o n s t h r e e months p r e v i o u s appear t o be as  impor-  t a n t as, o r perhaps more i m p o r t a n t t h a n , h y d r o g r a p h i c c o n d i t i o n s i n t h e p r e c e d i n g May al.  and June, d u r i n g a t i m e o f h i g h p r o d u c t i v i t y (Stephens e t  1969).  Two  h y d r o g r a p h i c e v e n t s a r e e v i d e n t i n August and September t h a t  might a f f e c t o v e r w i n t e r i n g p o p u l a t i o n s o f z o o p l a n k t o n .  There i s a de-  crease i n the d e n s i t y g r a d i e n t i n near s u r f a c e waters.  The breakdown o f  t h e d e n s i t y s t r a t i f i c a t i o n r e s u l t s from t h e c o o l i n g o f n e a r s u r f a c e water due t o a t m o s p h e r i c c o o l i n g , from t h e i n c r e a s e i n s u r f a c e s a l i n i t i e s caused by reduced f r e s h water r u n o f f , and from wind i n d u c e d m i x i n g p r o cesses.  As a r e s u l t , n u t r i e n t s a g a i n become a v a i l a b l e f o r a u t o t r o p h i c  uptake and a secondary p h y t o p l a n k t o n bloom may and Dodimead 1957)•  develop.iiin t h e f a l l  (Tully  The e x t e n t o f t h i s secondary bloom w i l l be a f u n c t i o n  o f t h e t i m i n g o f t h e appearance of s u f f i c i e n t m i x i n g t o renew t h e n u t r i e n t s  81  i n t h e e u p h o t i c zone.  I f t h e d e n s i t y g r a d i e n t b r e a k s down l a t e r than  u s u a l , n u t r i e n t s may n o t become a v a i l a b l e u n t i l t h e d a y l e n g t h has dec r e a s e d s u f f i c i e n t l y t o s e r i o u s l y hamper a u t o t r o p h i c p r o d u c t i o n .  Such a :  d e c r e a s e i n p r i m a r y p r o d u c t i o n would have a d e t r i m e n t a l e f f e c t on h e r b i v o r o u s s p e c i e s which must accumulate r e s e r v e s o f body l i p i d s t o m a i n t a i n t h e m s e l v e s over t h e w i n t e r . homogeneity to  C o n v e r s e l y , an e a r l y r e t u r n i t o  vertical  c o u l d r e s u l t i n a l a r g e f a l l bloom t h a t would be b e n e f i c i a l  many s p e c i e s . The second h y d r o g r a p h i c event o c c u r r i n g i n August/September  i s the  a n n u a l i n t r u s i o n of warm, h i g h s a l i n i t y deep water i n t o t h e S t r a i t of Georgia.  The c h a r a c t e r i s t i c s of t h e i n t r u d i n g water a r e d e r i v e d from  b o t h incoming Juan de F u c a i n t e r m e d i a t e water and f r e s h water r u n o f f t h a t a r e mixed t o g e t h e r i n t h e Southern Approaches  (Waldichuk 1957') •  I  n  my d a t a , t h i s i n t r u s i o n i s n o r m a l l y apparent i n August i n deep water, and i s always apparent i n September i n water below 200-300 m.  By November/  December, t h e e x t e n t o f t h e deep water mass has i n c r e a s e d due t o f u r t h e r i n t r u s i o n s and t o m i x i n g p r o c e s s e s . The o c c u r r e n c e of t h e i n t r u s i o n s u g g e s t s t h a t "water q u a l i t y " p a r a meters i n t h e S t r a i t o f G e o r g i a a r e c h a n g i n g .  D a t a from L e w i s • .. .  (1976) i n d i c a t e h i g h n i t r a t e i n Juan de F u c a deep water, which makes up p a r t of t h e i n t r u d i n g w a t e r mass.  I n c r e a s e s i n t h i s n u t r i e n t a r e o f im-  portance to future phytoplankton production.  Lewis et a l .  (I97i) have  shown an i n c r e a s e i n t h e l a b o r a t o r y s u r v i v a l of t h e p r e f e e d i n g s t a g e s o f P a r e u c h a e t a e l o n g a t a i n sea water c o l l e c t e d d u r i n g t h e f a l l  intrusion.  They suggest t h a t o r g a n i c s u b s t a n c e s found i n t h e i n t r u d i n g water c o u l d be a f f e c t i n g t h e s u i t a b i l i t y o f deep water f o r t h e s u r v i v a l of p r e f e e d i n g  82  stages of P. elongata.  Evans (1973), however, f e l t t h a t changes i n t h e  s u r v i v a l o f young s t a g e s o f P . e l o n g a t a were l e s s i m p o r t a n t than  morta-  l i t y o f l a t e r l i f e ' - h i s t o r y s t a g e s , and t h a t s u b t l e changes i n water q u a l i t y would n o t g e n e r a t e changes i n t h e p o p u l a t i o n s i z e o f t h e s p e c i e s . E v a n s i h y p o t h e s i s does n o t reduce t h e s u i t a b i l i t y o f young n a u p l i a r s t a g e s of  t h e organism t o l a b o r a t o r y t e s t i n g f o r changes i n water q u a l i t y .  Such  changes may have s u b t l e e f f e c t s on o t h e r s p e c i e s o r on t h e community a s a whole. R e l a t i o n s h i p s between t h e h y d r o g r a p h i c r e g i m e and z o o p l a n k t o n s i x months l a t e r appear t o a f f e c t a l l groups w i t h t h e e x c e p t i o n : o f t h e "group" c o n s i s t i n g o f C a l a n u s plumchrus o n l y (Group 4 b ) .  S i n c e s p r i n g i s t h e op-  timum r e p r o d u c t i v e p e r i o d f o r most z o o p l a n k t o n , t h e r e l a t i o n s h i p b b e t w e e n t h e h y d r o g r a p h i c regime i n s p r i n g and o v e r w i n t e r i n g z o o p l a n k t o n c o n c e n t r a t i o n s i s p r o b a b l y connected t o r e p r o d u c t i v e s u c c e s s .  Calanus  i s known t o breed w e l l b e f o r e t h e s p r i n g p h y t o p l a n k t o n bloom 1972). ciently. ble  plumchrus (Gardner  T h i s t i m i n g a p p a r e n t l y a l l o w s i t t o g r a z e t h e bloom more e f f i The development r a t e o f t h e younger s t a g e s appears t o be f l e x i -  and c o - o r d i n a t e d w i t h t h e a v a i l a b i l i t y o f phytoplankton('(Gardner 1972) .  The a b i l i t y t o t i m e development t o c o i n c i d e w i t h i n c r e a s e d p r i m a r y t i o n might make t h e younger d e v e l o p m e n t a l ation i n the phytoplankton.  produc-  stages l e s s s u s c e p t i b l e t o vari-^  The e a r l y developmentaof t h e p o p u l a t i o n might  a l s o make i t l e s s s u s c e p t i b l e t o h y d r o g r a p h i c v a r i a t i o n i n May and June. V a r i a t i o n s i n o t h e r s p e c i e s p r o b a b l y r e s u l t from a g r e a t e r s e n s i t i v i t y to  t h e e f f e c t s o f t h e h y d r o g r a p h i c regime on p r i m a r y p r o d u c t i v i t y ,  in  t u r n w i l l a f f e c t r e p r o d u c t i o n and s u r v i v a l o f t h e n e x t g e n e r a t i o n . In phase d a t a a l s o s u g g e s t , t h a t b o t h t e m p e r a t u r e  which  and s t a b i l i t y  83:  v a r i a t i o n s c o n t r i b u t e t o f l u c t u a t i o n s i n zooplankton species.  Since  t h e r e a r e no l a r g e - s c a l e h y d r o g r a p h i c e v e n t s d u r i n g t h e o v e r w i n t e r i n g p e r i o d , i t i s d i f f i c u l t t o a n a l y s e t h e importance o f s t a b i l i t y , any o t h e r h y d r o g r a p h i c f a c t o r s , w i t h o u t l o o k i n g a t more s p e c i f i c  or of hydro-  graphic/zooplanktonic relationships.  Regression analysis R e g r e s s i o n s u p p l i e s some o f t h e d e f i n i t i o n l a c k i n g i n t h e c a n o n i c a l a n a l y s i s a t t h e expense o f a l o s s o f g e n e r a l i t y . s u p p o r t t h e c o n c l u s i o n s based on t h e c a n o n i c a l c o r r e l a t i o n  The  results  coefficients.  In a d d i t i o n , t h e r e l a t i o n s h i p between h y d r o g r a p h i c parameters a t s p e c i f i c d e p t h s and s i n g l e z o o p l a n k t o n s p e c i e s can now  be e s t i m a t e d .  The l a r g e s t number o f s i g n i f i c a n t r e l a t i o n s h i p s o c c u r s w i t h s t a b i l i t y t h r e e months out o f phase.  C a n o n i c a l a n a l y s i s f i r s t suggested t h e  impor-  t a n c e o f t h e h y d r o g r a p h i c regime i n t h e l a t e summer, and r e g r e s s i o n anal y s i s now  shows t h a t t h e s t a b i l i t y s t r u c t u r e o f t h e water column i n l a t  August and September i s i m p o r t a n t t o over 50% o f t h e c o r e s p e c i e s .  Alsoso  most a l l o f t h e s t a b i l i t y v a r i a b l e s i n v o l v e d i n t h e s e r e l a t i o n s h i p s a r e near s u r f a c e parameters.  The d e n s i t y g r a d i e n t i n water d e e p e r than 200  i s e x t r e m e l y s m a l l ( c a . 0.002), and i s c l o s e r t o b e i n g a c o n s t a n t than a variable.  Consequently, r e l a t i o n s h i p s between t h e s i z e of o v e r w i n t e r i n g  p o p u l a t i o n s and t h e d e n s i t y s t r a t i f i c a t i o n  of deep water a r e not  statis-  t i c a l l y r e a l i s t i c , and r e l a t i o n s h i p s between n e a r s u r f a c e s t a b i l i t y  and  z o o p l a n k t o n c o n c e n t r a t i o n s a r e more l i k e l y t o b e i m e a n i n g f u l . Many o f t h e s p e c i e s which a r e r e l a t e d t o n e a r s u r f a c e s t a b i l i t y s p e c i e s found i n deep and i n t e r m e d i a t e water.  are  It is initially difficult  m  84  to  see t h e i m p o r t a n c e t o a deep water s p e c i e s o f s t a b i l i t y i n n e a r s u r -  f a c e water.  The f r e q u e n t o c c u r r e n c e  o f such a r e l a t i o n s h i p , however,•  suggests t h a t i t i s b i o l o g i c a l l y important. must be r a t h e r i n d i r e c t . lowing  The c o n n e c t i o n , i f r e a l ,  Some p o s s i b i l i t i e s a r e d i s c u s s e d i n t h e f o l -  paragraphs.  The r o l e o f d e n s i t y s t r a t i f i c a t i o n i n t h e f a l l p h y t o p l a n k t o n  bloom  p r o b a b l y b c o n t r i b u t e s t o t h e r e l a t i o n s h i p , and was c o n s i d e r e d i n d i s c u s s i n g the c a n o n i c a l c o r r e l a t i o n b f t s e v e r a l zooplankton s t a b i l i t y o f t h e whole water columnsin  l a t e summer.  groups w i t h t h e A weakly s t r a t i f i e d  water column would be more r e a d i l y broken down by m i x i n g p r o c e s s e s .  In  i n t e r p r e t i n g t h e c a n o n i c a l c o r r e l a t i o n i t was h y p o t h e s i z e d t h a t e a r l y m i x i n g would l e a d t o e a r l y n u t r i e n t r e g e n e r a t i o n and a s u b s t a n t i a l f a l l bloom o f p h y t o p l a n k t o n .  I f t h i s h y p o t h e s i s were t r u e , then t h e s l o p e o f  t h e r e l a t i o n s h i p between a z o o p l a n k t o n would be n e g a t i v e .  s p e c i e s and n e a r s u r f a c e  H i g h s t a b i l i t y would i m p l y reduced  stability  phytoplankton,  which i n t u r n would i m p l y reduced o v e r w i n t e r i n g p o p u l a t i o n s o f z o o p l a n k ton.  I n f a c t , f i v e o f t h e e i g h t r e g r e s s i o n e q u a t i o n s do have n e g a t i v e  s l o p e s , s u p p o r t i n g my h y p o t h e s i s .  Three s p e c i e s , however, i n c l u d i n g  C a l a n u s m a r s h a l l a e , have p o s i t i v e s l o p e s w i t h n e a r s u r f a c e s t a b i l i t y . These e x c e p t i o n s suggest t h a t o o t h e r f a c t o r s a r e i n v o l v e d i n t h e r e l a t i o n s h i p between z o o p l a n k t o n  and t h e s t a b i l i t y s t r u c t u r e o f t h e water column.  The e f f e c t o f water column s t r a t i f i c a t i o n on p h y t o p l a n k t o n  affects  overwintering zooplankton populations i n d i r e c t l y , since the phytoplankton a r e more a v a i l a b l e i n e a r l y f a l l .  A mechanism can be p o s t u l a t e d by which  n e a r s u r f a c e s t a b i l i t y i n August and September can more d i r e c t l y t h e o v e r w i n t e r i n g p o p u l a t i o n s o f deep water s p e c i e s .  affect  85  Near s u r f a c e s t a b i l i t y i n d i r e c t l y i n d i c a t e s t h e degree o f m i x i n g between f r e s h water r u n o f f and i n c o m i n g deep water.  Insolation pro-  c e s s e s i n n e a r s u r f a c e water a l s o a f f e c t t h e s t a b i l i t y s t r u c t u r e , b u t a r e n o t connected w i t h r u n o f f .  The r e l a t i v e i m p o r t a n c e o f t e m p e r a t u r e and  s a l i n i t y t o d e n s i t y g r a d i e n t s can be e s t i m a t e d from my d a t a by c a l c u l a t i n g t h e c o r r e l a t i o n between s t a b i l i t y and t h e two h y d r o g r a p h i c p a r a m e t e r s separately.  T h i s c o r r e l a t i o n shows t h a t n e a r s u r f a c e s t a b i l i t y i s more  highly correlated with the corresponding s a l i n i t y gradient ( r = p ^ O . O l ) than w i t h t h e t e m p e r a t u r e g r a d i e n t ( r = O.76, the  O.98,  p<;0.0l).  Hence  s t a b i l i t y i s a good a p p r o x i m a t i o n o f t h e s a l i n i t y g r a d i e n t i n n e a r  surface water. H i g h s t a b i l i t y i n n e a r s u r f a c e water i m p l i e s h i g h r u n o f f .  Increased  r u n o f f i m p l i e s t h a t more f r e s h water i s a v a i l a b l e f o r m i x i n g and  bottom  water f o r m a t i o n . Hence t h e c o n t r i b u t i o n of n e a r s u r f a c e water t o t h e deep w a t e r mass w i l l be g r e a t e r .  C o n v e r s e l y , i n a y e a r w i t h l e s s than  average: r u n o f f and a l o w e r d e n s i t y g r a d i e n t i n n e a r s u r f a c e water, l e s s f r e s h water w i l l be a v a i l a b l e f o r m i x i n g and t h e c o n t r i b u t i o n o f s u r f a c e water t o t h e deep water mass w i l l be d e c r e a s e d .  T h i s i s a tenuous sug-  g e s t i o n a t b e s t , and i s d i f f i c u l t ! , i f n o t i m p o s s i b l e , t o q u a n t i f y . e v e r , t h e t i m e l a g i n v o l v e d i n t h i s case I s t h r e e months.  How-  The f o r m a t i o n  of bottom water i n t h e S t r a i t of G e o r g i a p r e d a t e s t h e i n t r u s i o n a t Geo 1748  by about two t o t h r e e months ( L e w i s e t a l . 1971; Evans 1973;  unpub.).  Gardner  T h i s t i m i n g s u g g e s t s t h a t n e a r s u r f a c e e v e n t s i n J u l y and August  d i r e c t l y i n f l u e n c e t h e c o m p o s i t i o n of bottom water a t Geo 1748  i n November  and December, and s u p p o r t s t h e r e l a t i o n s h i p between n e a r s u r f a c e e v e n t s i n l a t e summer and o v e r w i n t e r i n g deep water z o o p l a n k t o n s p e c i e s .  This  86  more d i r e c t r e l a t i o n s h i p , a c t i n g i n c o n j u n c t i o n w i t h t h e e f f e c t o f s t a b i l i t y on p h y t o p l a n k t o n ,  can account f o r much o f t h e r o l e o f t h e h y d r o g r a -  p h i c regime i n August and September on t h e o v e r w i n t e r i n g  zooplankton.  Temperature r e l a t i o n s h i p s t h r e e months out o f phase a r e a l s o o f interest.  A l l t h r e e o f t h e amphipod s p e c i e s i n t h e c o r e s p e c i e s l i s t a r e  i n v e r s e l y r e l a t e d t o t e m p e r a t u r e a t 50 m.  The h i g h degree o f i n t e r c o r -  r e l a t i o n i n t h e s e s p e c i e s was shown p r e v i o u s l y i n t h e c o r r e l a t i o n a n a l y sis. ted  I t appears t h a t n e a r s u r f a c e t e m p e r a t u r e s i n l a t e summer a r e r e l a t o t h i s i n t e r c o r r e l a t i o n ? b u t i t i s d i f f i c u l t t o see how t h i s might  have come about.  The maximum c o n c e n t r a t i o n s o f t h e t h r e e amphipod s p e c i e s  a r e i n d i f f e r e n t r e g i o n s o f t h e water column d u r i n g o v e r w i n t e r i n g , so t h e c o n n e c t i o n may be v e r y i n d i r e c t , and w i l l - m e e d f u r t h e r study b e f o r e i t can be r e s o l v e d . Regressions  w i t h h y d r o g r a p h i c d a t a i n phase and s i x months,  out o f phase each g e n e r a t e  a s i m i l a r number o f s i g n i f i c a n t r e g r e s s i o n  e q u a t i o n s , b u t no s i n g l e parameter has a m a j o r i t y o f t h e r e g r e s s i o n s i n the way t h a t s t a b i l i t y d a t a dominated t h e r e l a t i o n s h i p s o f z o o p l a n k t o n w i t h h y d r o g r a p h i c d a t a t h r e e months out o f phase. relationships.  The h y d r o g r a p h i c  There a r e few obvious  regime i n s p r i n g a f f e c t s t h e ultimate-  s i z e of overwintering populations of zooplankton,  b u t t h e mechanisms a r e  d i f f i c u l t t o u n r a v e l because o f t h e c o m p l e x i t y o f events i n t h e i n t e r vening time p e r i o d .  The s u c c e s s o f b r e e d i n g may be i n v o l v e d , p a r t i c u l a r l y  i n those s p e c i e s w i t h annual l i f e c y c l e s .  The i n t e n s i t y o f t h e s p r i n g  bloom w i l l a l s o be i n v o l v e d a s i t w i l l d e t e r m i n e t h e a v a i l a b i l i t y .of f o o d for  t h e h e r b i v o r e s d i r e c t l y and t h e c a r n i v o r e s i n d i r e c t l y . I n phase r e g r e s s i o n s a r e c h a r a c t e r i z e d by r e l a t i o n s h i p s between deep  87  water t e m p e r a t u r e and deep water s p e c i e s .  S a l i n i t y and s t a b i l i t y  t i o n s h i p s a r e reduced and a f f e c t o n l y a few s p e c i e s . C a l a n u s plumchrus and C. m a r s h a l l a e important.  The  relaV  The r e g r e s s i o n s o f  a g a i n s t temperature are p a r t i c u l a r l y  i n v e r s e nature of the r e l a t i o n s h i p s suggests temperature,  o r a t e m p e r a t u r e r e l a t e d f a c t o r , as t h e d r i v i n g f o r c e behind a t i o n s of t h e two species-.  the  fluctu-  I t i s p o s s i b l e that the f a c t o r s generating  t h e f l u c t u a t i o n s a f f e c t o n l y one of t h e two s p e c i e s , and t h a t t h e s p e c i e s i n c r e a s e s or d e c l i n e s a c c o r d i n g l y y  The  other  egg p r o d u c t i o n of C a l a n u s  s p e c i e s i s on t h e o r d e r o f 200-300 eggs d u r i n g t h e b r e e d i n g  season (Mar-  s h a l l and O r r 1955b), s u f f i c i e n t f o r C ...-marshallae t o i n c r e a s e i n number s o l e l y due t o t h e f a v o r a b l e c o n d i t i o n s g e n e r a t e d by a d e c l i n e i n C a l a n u s plumchrus, and t o a l l o w such an i n c r e a s e t o o c c u r w i t h o u t a n o t i c e a b l e time l a g .  Conversely,  a change i n a f a c t o r l i m i t i n g o n l y t h e p o p u l a t i o n  d e n s i t y of C. m a r s h a l l a e might a l l o w C. m a r s h a l l a e to the detriment  o f C. plumchrus.  t o i n c r e a s e i n numbers  E i t h e r of t h e s e p o s s i b i l i t i e s  c r e a t e an a r t i f i c i a l r e g r e s s i o n between t h e second s p e c i e s and  could  tempera-  t u r e , but would not m a t e r i a l l y a l t e r t h e f a c t t h a t t e m p e r a t u r e or a temp e r a t u r e r e l a t e d f a c t o r was r e s p o n s i b l e f o r t h e f l u c t u a t i o n s i n number. The f a c t t h a t a t e m p o r a l t r e n d common t o t h e whole z o o p l a n k t o n e x i s t s , as w i l l be d i s c u s s e d l a t e r , s t r o n g l y s u p p o r t s t h e  community  hypothesis  t h a t t h e f a c t o r s r e s p o n s i b l e f o r f l u c t u a t i o n s i n number a r e a c t i n g on  the  community as a u n i t , r a t h e r t h a n on i n d i v i d u a l s p e c i e s . I n the case of C a l a n u s plumchrus and Calanus m a r s h a l l a e ,  a suffi-:V.  c i e n t l y abnormal t e m p e r a t u r e might s h i f t t h e e q u i l i b r i u m between t h e s p e c i e s s u f f i c i e n t l y t h a t one s p e c i e s c o u l d r e p l a c e t h e o t h e r . t i o n t o be d i s c u s s e d i n t h e l a b o r a t o r y r e s u l t s s u g g e s t s t h a t t h e  Informa-  88  replacement of C. m a r s h a l l a e by G. plumchrus i s more l i k e l y t o t h a n the replacement of G. plumchrus by G.  occur  marshallae.  F a c t o r and p r i n c i p a l components a n a l y s i s F a c t o r a n a l y s i s and p r i n c i p a l components a n a l y s i s b o t h  indi-  c a t e t h e degree t o which t h e o r i g i n a l d a t a c o u l d c o n c e i v a b l y have been reduced i f t h e i n t e r a c t i o n s o f i n d i v i d u a l s p e c i e s had n o t been c o n s i d e r e d as i m p o r t a n t as the i n t e r a c t i o n s o f groups o f s p e c i e s . The f a c t o r a n a l y s i s i n d i c a t e s a c o n s i d e r a b l e amount o f redundancy i n the zooplankton data.  The f i r s t 8 f a c t o r s y i e l d almost a l l o f t h e  variance i n a zooplankton  m a t r i x o f 32 groups.  F u l l y h a l f o f the  total  v a r i a n c e i s c o n t a i n e d In two f a c t o r s which can be r o u g h l y e s t i m a t e d by few as f o u r key s p e c i e s .  The  composition  of the f a c t o r s supports  as  earlier  c o n c l u s i o n s based on r e g r e s s i o n and c a n o n i c a l a n a l y s i s . The f i r s t f o u r f a c t o r s are d i s t r i b u t i o n oriented.  The a s s o c i a t i o n o f deep water s p e c i e s  w i t h t h e f i r s t f a c t o r , which y i e l d s s 3 4 % o f t h e z o o p l a n k t o n v a r i a n c e , i n d i c a t e s t h e dominance o f deep water s p e c i e s i n the. community.  Species  w i t h deep water maxima dominate the t h i r d f a c t o r as w e l l , and c o n t r i b u t e h e a v i l y t o t h e second.  The f o u r t h f a c t o r , however, i s a s s o c i a t e d o n l y  w i t h s p e c i e s h a v i n g maximum c o n c e n t r a t i o n s at. i n t e r m e d i a t e d e p t h s .  There  i s no f a c t o r s p e c i f i c a l l y r e l a t e d t o s p e c i e s found p r i m a r i l y i n n e a r s u r f a c e o r b o t h n e a r s u r f a c e and i n t e r m e d i a t e w a t e r .  These s p e c i e s aree  a s s o c i a t e d w i t h t h e f i r s t f a c t o r , on which t h e y have h i g h n e g a t i v e loadings. R e - f a c t o r i n g t h e 13 s p e c i e s a s s o c i a t e d w i t h t h e f i r s t f a c t o r c o n f i r m s t h a t i t i s p r i m a r i l y a s s o c i a t e d w i t h deep water s p e c i e s , but i n d i c a t e s  89  t h a t t h e n e a r s u r f a c e s p e c i e s s h o u l d n o t be d i s r e g a r d e d as t h e y account f o r approximately  can  Jk% o f t h e v a r i a n c e a s s o c i a t e d w i t h t h e f a c t o r .  F u r t h e r d i v i s i o n s w i t h i n t h i s group o f 13 s p e c i e s appear t o be a s s o c i a t e d with specific d i s t r i b u t i o n patterns. The  second f a c t o r i n g does not y i e l d much new  community s t r u c t u r e , but s u g g e s t s  i n f o r m a t i o n on  the  which s p e c i e s c o u l d b e s t be used t o  r e p r e s e n t t h e f i r s t major f a c t o r of t h e whole s p e c i e s m a t r i x .  Using  i n f o r m a t i o n generated  distribu-  by t h e f a c t o r a n a l y s i s , and t h e v e r t i c a l  t i o n p a t t e r n s i n d i c a t e d by o t h e r a n a l y s e s , a s m a l l group o f s p e c i e s be s e l e c t e d which a r e r e p r e s e n t a t i v e o f t h e g e n e r a l community.  can  Such a  group might c o n t a i n C a l a n u s plumchrus, P s e u d o c a l a n u s minutus, A c a r t i a longiremus,  S a g i t t a e l e g a n s , E u p h a u s i a p a c i f i c a , L i m a c i n a sp. and  spinirostris.  These seven s p e c i e s , which a r e a l l V r e a d i l y i d e n t i f i e d ,  t h e major r e p r e s e n t a t i v e s i n f a c t o r s a c c o u n t i n g f f o r 75% the zooplankton  Oithona  community.  Use  are  of t h e v a r i a n c e i n  o f t h e s e s p e c i e s o n l y would n o t e l i m i n a t e  s o r t i n g samples c o m p l e t e l y , b u t c o u l d a c t as a p r e l i m i n a r y check.  I f data  f r o m t h i s b l o c k o f s p e c i e s i n d i c a t e d g r e a t e r than u s u a l v a r i a t i o n i n t h e overwintering zooplankton,  o r changes i n t h e r e l a t i o n s h i p s between major  s p e c i e s , then i t might be a d v i s a b l e t o s o r t and count samples more t h o roughly.  Otherwise,  t h e amount of work i n v o l v e d i n m o n i t o r i n g t h e zoo-  p l a n k t o n community c o u l d be g r e a t l y In many c a s e s , z o o p l a n k t o n  decreased.  m o n i t o r i n g programmes a r e n o t  s p e c i f i c , and y i e l d d a t a s u c h as "wet t o n " , " t o t a l copepods", "zooplankton  w e i g h t biomass of t o t a l displacement  measures o f abundance ( e . g . Stephens e t a l . I969). a r e monitored,  species zooplank-  volume" o r s i m i l a r When i n d i v i d u a l  t h e s p e c i e s a r e c o f t e n chosen s u b j e c t i v e l y r a t h e r than  species  90  objectively.  There can be c o n s i d e r a b l e m e r i t t o t h e s e approaches, depen-  d i n g on t h e p u r p o s e s f o r which t h e d a t a a r e c o l l e c t e d ; however, i t i s dangerous t o lump s p e c i e s h a p h a z a r d l y .  F a c t o r a n a l y s i s p r o v i d e s an  ob-  j e c t i v e c r i t e r i o n f o r s e l e c t i n g key s p e c i e s when- i t i s n e i t h e r l o g i s t i c c a l l y nor economically f e a s i b l e t o monitor a l l s p e c i e s . such as t h e economic importance  Other c r i t e r i a ,  of c e r t a i n species, or the  contribution  o f a s p e c i e s t o t h e community biomass, c o u l d a l s o be c o n s i d e r e d , but i f t h e o b j e c t i v e i s t o m o n i t o r t h e community r a t h e r than p a r t i c u l a r s p e c i e s , i t i s e s s e n t i a l t h a t t h e s p e c i e s chosen be r e p r e s e n t a t i v e o f t h a t community. These s u g g e s t i o n s a r e p r i m a r i l y d e s i g n e d f o r t h e m o n i t o r i n g o f y e a r t o y e a r v a r i a t i o n w i t h i n t h e zooplankton,. examinatiohoof  l2They.tcouldiberadapt,edDtOiT.an°;  s e a s o n a l v a r i a t i o n , b u t i t would p r o b a b l y be more d i f f i c u l t  t o s e l e c t s p e c i e s which a d e q u a t e l y r e p r e s e n t t h e community throughout year.  the  I t would a l s o be b e t t e r t o m o n i t o r a l a r g e r number o f s p e c i e s i n  a s e a s o n a l s u r v e y i f s p e c i e s s p e c i f i c d a t a were r e q u i r e d , as might be t h e case i n a s t u d y o f s p e c i e s s u c c e s s i o n , or i n a b a s e l i n e s t u d y . S i m i l a r d a t a r e d u c t i o n methods can be a p p l i e d t o t h e m o n i t o r i n g of h y d r o g r a p h i c v a r i a b l e s , but t h e g a i n i s n o t as a p p r e c i a b l e as t h e number of h y d r o g r a p h i c . v a r i a b l e s i s n o r m a l l y a l r e a d y reduced due t o t h e l o g i s t i c s of d a t a c o l l e c t i o n and t h e p r e l i m i n a r y s e l e c t i o n of r e p r e s e n t a t i v e depths.  As a r e s u l t , p r i n c i p a l components a n a l y s i s of my d a t a i n -  d i c a t e s t h a t t h e r e i s l e s s redundancy i n t h e m a t r i x o f h y d r o g r a p h i c t h a n t h e r e was  i n the zooplankton d a t a .  The d a t a a r e v e r y s t r o n g l y  r e l a t e d t o t h e water column s t r u c t u r e a t Geo i s n o t unexpected,  data  17^8.  This r e l a t i o n s h i p  as t h e d i v i s i o n o f t h e water column a t t h i s  station  91  i n t o t h r e e s e p a r a t e b o d i e s of water i s w e l l known ( e . g . Gardner 1972). However, water masses a r e more n o r m a l l y d e s i g n a t e d by i n s p e c t i o n of a s e r i e s of t e m p e r a t u r e / s a l i n i t y c u r v e s from t h e a r e a under  investigation.  P r i n c i p a l components a n a l y s i s can be used e i t h e r as a check on a r b i t r a r y d e s i g n a t i o n o f r e g i o n s w i t h i n t h e water column o r as a method f o r def i n i n g such r e g i o n s from c o l l e c t e d d a t a .  The method c o u l d a l s o be used  i n t h e d e s c r i p t i o n ^ of: water masses i n t h e open ocean.  The  difficultyx  w i t h u s i n g p r i n c i p a l components a n a l y s i s i n t h i s manner i s t h a t b o t h r e g i o n s o f t h e water column and t r u e water masses a r e d e f i n e d on t h e b a s i s o f two u s u a l l y independent v a r i a b l e s , n e i t h e r o f which i s n e c e s s a r i l y sufficient in itself.  T a k i n g t h e p r i n c i p a l components of t e m p e r a t u r e and  s a l i n i t y s e p a r a t e l y and comparing t h e r e s u l t s would be one p o s s i b l e  way  t o d e t e r m i n e t h e s t r u c t u r e o f the whole b l o c k o f h y d r o g r a p h i c d a t a . A l t e r n a t i v e l y , t h e f r e q u e n c y d i s t r i b u t i o n of a s e r i e s o f twod i m e n s i o n a l s q u a r e s ( t e m p e r a t u r e x s a l i n i t y ) c o u l d be d e t e r m i n e d ( e . g . Montgomery 1955. methods.  Hansen 1973)  and a n a l y s e d by p r i n c i p a l components  I n most c a s e s , t h i s t r e a t m e n t would p r o b a b l y be as t e d i o u s and  t i m e consuming as t r a d i t i o n a l methods.  However, i n an a r e a where w a t e r s  from many d i f f e r e n t s o u r c e s a r e i n t e r a c t i n g and c o n s t a n t l y s h i f t i n g ,  and  a complex mass of d a t a i s r e a d i l y accumulated and n o t so r e a d i l y d e c i phered, s t a t i s t i c a l t e c h n i q u e s o f t h i s t y p e would be more e f f i c i e n t i n d e f i n i n g and k e e p i n g t r a c k of water s t r u c t u r e .  The o b j e c t i v i t y o f p r i n -  c i p a l components a n a l y s i s as compared w i t h t r a d i t i o n a l t e c h n i q u e s , enhances t h e a p p e a l o f s t a t i s t i c a l approaches t o t e m p e r a t u r e / s a l i n i t y a n a l y sis.  As advanced computer t e c h n o l o g y makes such a n a l y s e s more r e a d i l y  a v a i l a b l e and l e s s cumbersome, t h e y w i l l p r o b a b l y become more w i d e l y  92  a c c e p t e d and used.  They have t h e a d d i t i o n a l advantage o f b e i n g more  t r a c t a b l e t o m o d e l l i n g o r t o n u m e r i c a l m a n i p u l a t i o n than  traditional  approaches. Wang and Walsh (1976), f o r example, have r e c e n t l y used p r i n c i p a l components a n a l y s i s ( e m p i r i c a l o r t h o g o n a l f u n c t i o n a n a l y s i s i n t h e i r t e r m i n o l o g y ) t o examine t h e h o r i z o n t a l and s p a t i a l t e m p o r a l v a r i a t i o n s of an u p w e l l i n g ecosystem.  T h e i r d a t a i n c l u d e d v a l u e s f o r s u r f a c e tem-  p e r a t u r e , c h l o r o p h y l l f l o u r e s c e n c e and n u t r i e n t d i s t r i b u t i o n s a s w e l l as d e n s i t y and n u t r i e n t d i s t r i b u t i o n s w i t h i n t h e w a t e r column.  They  s e p a r a t e d n u t r i e n t uptake p r o c e s s e s f r o m t h e dominant c o n s e r v a t i v e p r o c e s s e s , and were a b l e t o d i s c u s s t h e l a r g e - s c a l e c h a r a c t e r i s t i c s o f t h e u p w e l l i n g ecosystem i n a m e a n i n g f u l l w a y .  Wang and Walsh were concerned  more w i t h i s o l a t i n g i n f o r m a t i o n c o n c e r n i n g t h e b i o l o g i c a l p r o c e s s e s with studying the p h y s i c a l processes.  than  However, t h e y suggest t h a t p r i n -  c i p a l components a n a l y s i s i s a p o w e r f u l t o o l f o r o b j e c t i v e l y a n a l y s i n g s e t s o f oceanographic  data.  S t a b i l i t y d a t a can be used i n a d d i t i o n t o t e m p e r a t u r e and s a l i n i t y d a t a t o check t h e b o u n d a r i e s  o f r e g i o n s o f t h e water column a t Geo 17^8.  D e s p i t e t h e r e l a t i v e l a c k o f s t a b i l i t y s t r u c t u r e below 200 m, t h e second s t a b i l i t y e i g e n v e c t o r , on which deep water s t a b i l i t y v a l u e s have h i g h l o a d i n g s , a c c o u n t s f o r 35% o f t h e v a r i a n c e i n t h e m a t r i x o f s t a b i l i t y data.  Such a h i g h l o a d i n g i n d i c a t e s t h a t deep water d e n s i t y s t r u c t u r e  s h o u l d n o t be i g n o r e d d e s p i t e t h e a l m o s t n e g l i g i b l e d e n s i t y g r a d i e n t . The p r i n c i p a l components aloheado n o t g i v e much i n s i g h t i n t o tern-.p o r a l t r e n d s i n t h e h y d r o g r a p h i c regime.  I f a s e r i e s o f d a t a s e t s , each  c o v e r i n g s e v e r a l years', c o u l d be assembled, then changes i n i n t e r n a l  93  s t r u c t u r e might be m a n i f e s t e d as changes i n t h e component s t r u c t u r e with time.  As w i t h c o r r e l a t i o n m a t r i c e s , t h e c u r r e n t l y used d a t a a r e  n o t s u f f i c i e n t i n scope f o r t h i s t y p e o f a n a l y s i s .  P r i n c i p a l components  a n a l y s i s , however, g e n e r a t e s i n f o r m a t i o n c o n c e r n i n g t h e r a n k o r d e r i n g o f s t a n d a r d i z e d c a s e s on t h e d e r i v e d p r i n c i p a l components, and  essentially  i n d i c a t e s , i n o r d e r , t h e r e l a t i v e c o n t r i b u t i o n o f each case t o each component . T h i s i n f o r m a t i o n c o n f i r m s t h e p r e s e n c e of a d e f i n i t e temporalt t r e n d i n t h e h y d r o g r a p h i c d a t a monitored d u r i n g t h e s t u d y p e r i o d . The r a n k i n g s on t h e f i r s t p r i n c i p a l component o f temperature separ a t e t e m p e r a t u r e d a t a t a k e n between October I969 and December 1970 t e m p e r a t u r e d a t a t a k e n between November 1971 component r e p r e s e n t s 53%  and December 197^-  from This  o f t h e v a r i a n c e i n t e m p e r a t u r e , and i s a s s o c i a t e d  more c l o s e l y w i t h t e m p e r a t u r e s from below 50  m.  The h i g h r a n k i n g of d a t a  from t h e second h a l f of t h e s a m p l i n g p e r i o d , a f t e r December 1970,  on t h e  f i r s t component o f t h e temperature m a t r i x , s u g g e s t s t h a t most of t h e v a r i a t i o n i n t h e t e m p e r a t u r e d a t a has o c c u r r e d s i n c e t h e s t a r t o f t h e f l u c t u a t i o n s i n Calanus plumchrus and C. m a r s h a l l a e , and was p r i m a r i l y a s s o c i a t e d w i t h water below 50  m.  component, which a c c o u n t s f o r 76% s e p a r a t e I969 d a t a from 1973  The r a n k i n g s on t h e f i r s t  salinity  of the v a r i a n c e i n the s a l i n i t y matrix,  and I974 d a t a , and suggest t h a t much o f t h e  s a l i n i t y v a r i a n c e i s associated w i t h the f i r s t p a r t of the sampling p e r i o d . T h i s component i s a l s o more c l o s e l y a s s o c i a t e d w i t h deep water t h a n w i t h n e a r s u r f a c e water. S t a b i l i t y f a c t o r s a r e n o t as s t r o n g l y t e m p o r a l i n t h e i r  orientation.  However, t h e r a n k i n g s on s a l i n i t y / a r e t h e i n v e r s e o f t h o s e on t e m p e r a t u r e . The h i g h e s t r a n k i n g s on t h e f i r s t t e m p e r a t u r e component go t o t h e most  94  r e c e n t months, w h i l e t h e h i g h e s t r a n k i n g s on t h e f i r s t s a l i n i t y go t o t h e e a r l i e s t months.  component  S i n c e temperature and s a l i n i t y b o t h i n f l u e n c e  d e n s i t y , c o n s i s t e n c y i n t h e r a n k i n g s on s t a b i l i t y components can n o t be expected. The p r i n c i p a l components a n a l y s i s o f h y d r o g r a p h i c d a t a showed t h e p r e s e n c e o f a y e a r t o y e a r t r e n d i n t h e temperature and s a l i n i t y v a l u e s . P r i n c i p a l components a n a l y s i s o f t h e z o o p l a n k t o n d a t a adds t o t h e e v i d e n c e for  a temporal s h i f t .  The p r i n c i p a l components o f t h e c o r e z o o p l a n k t o n  s p e c i e s a r e l e s s s t r i k i n g than t h e f a c t o r s g e n e r a t e d by t h e f a c t o r a n a l y s i s . S i m i l a r r e l a t i o n s h i p s between s p e c i e s groups and f a c t o r s a r e a p p a r e n t , b u t t h e r e a r e n o t h i g h f a c t o r l o a d i n g s , p r o b a b l y due t o r e s t r i c t i n g t h e a n a l y s i s t o c o r e s p e c i e s and thus r e d u c i n g t h e v a r i a n c e i n t h e m a t r i x b e i n g factored.  From t h e s t a n d p o i n t o f t e m p o r a l change, however, t h e i n t e r e s t  t i n g and i m p o r t a n t p a r t o f t h e p r i n c i p a l components a n a l y s i s o f t h e zoop l a n k t o n i s t h e r a n k i n g o f t h e s t a n d a r d i z e d c a s e s on t h e components. The t e m p o r a l s h i f t i s n o t a s apparent i n t h e z o o p l a n k t o n m a t r i x as i t was i n t h e h y d r o g r a p h i c d a t a .  The f i r s t component, which a c c o u n t s f o r  36% o f t h e z o o p l a n k t o n v a r i a n c e , i s d i s t r i b u t i o n a l .  I t r e i t e r a t e s the  importance o f deep water s p e c i e s groups w i t h i n t h e z o o p l a n k t o n community. The second component s u p p o r t s t h e f i r s t a a n d i n d i c a t e s t h a t 19% o f t h e zoop l a n k t o n v a r i a n c e i s a s s o c i a t e d w i t h i n t e r m e d i a t e d e p t h samples which have no t e m p o r a l a s s o c i a t i o n .  The t h i r d component, however, has no o b v i o u s  d e p t h o r s p e c i e s a s s o c i a t i o n s , y e t a c c o u n t s f o r 15% o f t h e z o o p l a n k t o n variance.  I t i s strongly temporally oriented.  d a t a from between December 1971  The f i r s t 15 r a n k s go t o  and December 1974.  The l o w e s t 12  go t o d a t a from between October I969 and December 1970.  ranks  November and  95  December 1971.  t h e months i n which t h e s h i f t i n C a l a n u s plumchrus and  m a r s h a l l a e was f i r s t n o t e d , h a v e b i n t e r m e d i a t e r a n k i n g s .  C.  The t e m p o r a l l y  a s s o c i a t e d z o o p l a n k t o n v a r i a n c e o b v i o u s l y o r i g i n a t e d a t t h e same t i m e as the  i n i t i a l s h i f t i n t h e two C a l a n u s s p e c i e s , and has been p r e s e n t s i n c e  that time.  N e i t h e r C a l a n u s n o r any o t h e r s p e c i e s has a h i g h l o a d i n g on  the  t h i r d ' f a c t o r ; however. vThe temp or a l t t r e n d i s a s s o c i a t e d more w i t h  the  community i n g e n e r a l than w i t h any p a r t i c u l a r s p e c i e s .  J  The t e m p o r a l i t y which i s e v i d e n t i n t h e f a c t o r s of t h e two p r i m a r y h y d r o g r a p h i c parameters i s a m a t h e m a t i c a l e x p r e s s i o n o f t h e changes i n S t r a i t o f G e o r g i a deep water which a r e r e p r e s e n t e d i n F i g u r e s '3, 4 and •5. These f i g u r e s i n d i c a t e d a s h i f t i n deep water s a l i n i t y and a l e s s w e l l — - ' d e f i n e d s h i f t i n deep water t e m p e r a t u r e .  The s t a t i s t i c a l a n a l y s e s sug-  g e s t t e m p e r a t u r e o r t e m p e r a t u r e a s s o c i a t e d phenomena t o be t h e paramet e r s ) which a f f e c t ( s ) t h e b i o l o g i c a l system t h e most, and a l l o w t h e changes i n hydrography t o be more c l e a r l y d e f i n e d t h a n i s p o s s i b l e from the  raw d a t a .  96  ASPECTS OF THE ECOLOGY OF THE APPARENTLY CO-OCCURRING SPECIES CALANUS PLUMCHRUS MARUKAWA AND C. MARSHALLAE FROST Introduction The apparent c o - o c c u r r e n c e  of congeneric  species raises the p o s s i -  b i l i t y t h a t c o m p e t i t i o n may be o c c u r r i n g between them.  According t o the  c l a s s i c a l formulation of the competitive exclusion p r i n c i p l e  (Hardin  i960) one o f t h e s p e c i e s s h o u l d , g i v e n s u f f i c i e n t t i m e f o r an e q u i l i b r i u m t o be reached,  replace the other.  T h i s r e p l a c e m e n t w i l l n o t occur  i f t h e r e a r e f a c t o r s which w i l l a c t t o s e p a r a t e t h e n i c h e s o f t h e s i m i l a r ' species.  There i s c o n s i d e r a b l e c o n t r o v e r s y over t h e degree o f i m p o r t a n c e  which t h e c o m p e t i t i v e e x c l u s i o n p r i n c i p l e might have i n t h e " r e a l w o r l d " . D i f f i c u l t i e s i n d e f i n i n g a n i c h e f o r any one s p e c i e s , i n e v a l u a t i n g l i m i t i n g r e s o u r c e s , and i n e v a l u a t i n g t h e s t a b i l i t y o f p o p u l a t i o n s a l l contribute to this Hutchinson  controversy. (I96I) s u g g e s t s t h a t a l t h o u g h t h e p r i n c i p l e may n o t be  a p p l i c a b l e t o t h e plankton, t h e types of competition described i n the t h e o r y c o u l d s t i l l be p r e s e n t .  The a s s u m p t i o n u n d e r l y i n g t h e c l a s s i c a l  concept o f c o m p e t i t i o n i s t h a t t h e r e i s a common r e s o u r c e t h a t i s l i m i ting.  Congeneric  s p e c i e s a r e more l i k e l y t o c o - o c c u r  i f the resources  t h e y e x p l o i t a r e p a r t i t i o n e d i n such a way as t o m i n i m i z e t h e o v e r l a p between t h e a r e a s which t h e y  utilize.  C a l a n u s m a r s h a l l a e and C_. plumchrus appear t o co-occur o f G e o r g i a , and t h e f l u c t u a t i o n s which have been observed  i n the S t r a i t  i n t h e numbers  o f t h e two s p e c i e s suggest t h e p o s s i b i l i t y t h a t t h e changes i n t h e i r p o p u l a t i o n s i z e s a r e l i n k e d and t h a t G. m a r s h a l l a e may have i n c r e a s e d i n numbers t o t h e d e t r i m e n t o f C. plumchrus ( p e r s . o b s . ) .  The two s p e c i e s  are morphologically s i m i l a r , d i f f e r i n g p r i m a r i l y i n s i z e .  They a r e b o t h  97  l a r g e compared t o most o t h e r c a l a n o i d copepods.  The prosome l e n g t h o f t h e  f i f t h c o p e p o d i t e s t a g e o f C a l a n u s plumchrus i s 3.90+0.15 mm, w h i l e t h a t o f C. m a r s h a l l a e unpub.). The  i s 2.74+0.11 mm (mean + one s t a n d a r d d e v i a t i o n : Gardner,  Both species are herbivorous  and t h e y have s i m i l a r l i f e c y c l e s .  s i m i l a r i t y b e t w e e n i t h e s e two s p e c i e s s u g g e s t s t h a t u n l e s s  a r e d i f f e r e n c e s between them w h i c h a l l o w them t o e x p l o i t n i c h e s , t h e y may be i n c o m p e t i t i o n .  there  non-overlapping  E c o l o g i c a l separation of outwardly  s i m i l a r s p e c i e s may be due t o d i f f e r e n c e s i n d i s t r i b u t i o n , f e e d i n g o r l i f e history.  These p a r a m e t e r s w i l l be examined t o d e t e r m i n e ifj/t'hey-  c o n t r i B u t e t t o n i c h e t s e p a r a t i o n between t h e two copepod s p e c i e s .  In addi-  t i o n , t h e f o o d v a l u e o f t h e s p e c i e s w i l l be examined t o g a i n some a p p r e c i a t i o n f o r t h e e f f e c t t h a t t h e change i n numbers i n t h e two s p e c i e s might have on h i g h e r t r o p h i c l e v e l s .  98  Distribution R e p r e s e n t a t i v e Clarke-Bumpus tows were s o r t e d as p r e v i o u s l y d e s c r i b e d (pp. 20, 21) t o e s t a b l i s h t h e v e r t i c a l d i s t r i b u t i o n o f t h e two s p e c i e s . T h e i r d i s t r i b u t i o n s were known t o o v e r l a p h o r i z o n t a l l y i n t h e S t r a i t o f G e o r g i a f r o m p r e v i o u s surveys,(Woodhouse 1971; Gardner 1972).  99  Feeding Introduction F e e d i n g experiments w i t h Calanus plumchrus (Pandyan 1971; Gardn e r unpub.) i n d i c a t e t h a t t h e f i f t h c o p e p o d i t e s t a g e (CV) f e e d s f o r o n l y a s h o r t t t i m e b e f o r e i t a p p a r e n t l y ceases f e e d i n g and m i g r a t e s i n t o deep water.  V e r y young CV's and e a r l i e r c o p e p o d i t e s a r e d i f f i c u l t t o o b t a i n  and a r e p r e s e n t f o r o n l y a s h o r t t i m e each y e a r .  In addition, feeding  e x p e r i m e n t s w i t h copepods a r e e x t r e m e l y p r o n e t o e r r o r and v a r i a t i o n . F o r t h e s e r e a s o n s , I have c o n c e n t r a t e d on measurements o f t h e m e c h a n i c a l feeding a b i l i t y  o f C a l a n u s plumchrus and C. m a r s h a l l a e •  The p r o c e s s o f f i l t r a t i o n  i n copepods h a s been w e l l d e s c r i b e d (Mar-  s h a l l and O r r 1955b; Gauld 1964; M a r s h a l l 1973). appendages a r e t h e second m a x i l l a e .  The main  filtering  These p a i r e d appendages form a  " f i l t e r i n g b a s k e t " through which water i s p a s s e d .  The a b i l i t y  of the  organism t o f e e d on p a r t i c l e s o f a g i v e n s i z e range w i l l depend upon t h e s m a l l e s t openings i n t h e meshes o f t h e f i l t e r i n g a p p a r a t u s .  The s i z e o f  t h e s e openings w i l l be a d i r e c t f u n c t i o n o f t h e d i s t a n c e between i n d i v i d u a l s e t u l e s on t h e s e t a e o f t h e second m a x i l l a .  This spacing i s  termed t h e i n t e r - s e t u l e d i s t a n c e ( I S D ) .  Procedure The  The second m a x i l l a e o f s e v e r a l specimens-sof t h e f i f t h copepo-  d i t e o f Calanus plumchrus and G. m a r s h a l l a e were removed by m i c r o - d i s s e c t i o n and mounted on g l a s s s l i d e s i n CMC-S, a n o n - r e s i n o u s s t a i n i n g mountant.  The m a x i l l a e were examined and d i v i d e d i n t o zones w i t h i n  t h e ISD's were a p p r o x i m a t e l y u n i f o r m .  which  The o u t l i n e o f each m a x i l l a was  100  drawn to scale using a camera l u c i d a mounted on a Wild M-20 compound microscope equipped with phase contrast.  The r e l a t i v e area of each zone  was measured from the drawings using a polar planimeter.  Ten ISD's were  used to calculate the mean ISD f o r each zone of each of twelve d i f f e r e n t maxillae.  The f i l t e r i n g e f f i c i e n c y f o r p a r t i c l e s of a given s i z e was  then calculated according to Nival and Nival's (1973) equation (Eqn 1 ) .  D, -x. J 2s. k  n I F^EP.I 1  where:  j = l ^  . T 2  S j  (2TT)  *e  3  (Eqn 1)  2  i s the f i l t e r i n g e f f i c i e n c y f o r p a r t i c l e s of diameter D^  1 to  p . i s the proportion of the t o t a l f i l t e r i n g surface belonging the j  zone  X = x - 2s^ (two standard deviations below the mean ISD of zone l ) i = x + 2s s  (two standard deviations above the mean ISD of zone 1)  i s the standard deviation of the ISD of zone ' j '  x. J  i s the mean ISD of zone ' j '  E f f i c i e n c i e s calculated f o r A c a r t i a c l a u s i i using t h i s equation have shown a good f i t with the r e s u l t s of short term grazing experiments, and appear to be a good estimate of basic f i l t e r i n g a b i l i t y and N i v a l 1976).  (Nival  The r e s u l t s f o r Calanus plumchrus and C. marshallae  were plotted as f i l t e r i n g a b i l i t y versus p a r t i c l e diameter, a curve of t h e o r e t i c a l mechanical feeding a b i l i t y .  yielding  101  R e a r i n g and B r e e d i n g Introduction D i f f i c u l t i e s a r e o f t e n encountered i n s u c c e s s f u l l y m a i n t a i n i n g populations of zooplankton  i n t h e l a b o r a t o r y ( K i n n e 1970).  Although  some s u c c e s s has been o b t a i n e d w i t h c e r t a i n s p e c i e s ( e . g . Z i l l i o u x and W i l s o n I966; H e i n l e 1969; L e w i s and Ramnarine 1969; Borgmann 1973a, b ) , good l a b o r a t o r y d a t a on z o o p l a n k t o n  populations are scarce.  The e v a l u a -  t i o n o f e c o l o g i c a l r e l a t i o n s h i p s between s p e c i e s , however, can be a i d e d by l a b o r a t o r y d e r i v e d e s t i m a t e s o f p h y s i o l o g i c a l r a t e s . o f a s p e c i e s may be i m p o r t a n t e x p l o i t i t s environment.  The growth r a t e  i n allowing that species t o e f f i c i e n t l y  E s t i m a t e s o f t h e growth r a t e may be r e a d i l y  o b t a i n e d i n t h e l a b o r a t o r y i f t h e s p e c i e s can be r e a r e d t h r o u g h  one com-  plete l i f e cycle.  Procedure O v i g e r o u s f e m a l e s o f each s p e c i e s were k e p t i n 150 ml t e s t t u b e s o f f i l t e r e d s e a water (Geo 1748, 350 m) i n an i n c u b a t o r a t 8 G. T h i s t e m p e r a t u r e a p p r o x i m a t e s ambient s e a w a t e r t e m p e r a t u r e s i n t h e environment.  A f t e r egg l a y i n g , t h e a d u l t s were removed and t h e growth o f  t h e young s t a g e s o b s e r v e d .  Water was changed a t f o u r t o f i v e day i n t e r -  v a l s and t h e d e v e l o p i n g n a u p l i i were f e d by t h e a d d i t i o n o f p h y t o p l a n k t o n . One s e r i e s (A) r e c e i v e d a m i x t u r e o f I s o c h r y s i s s p . and D u n a l i e l l a s p . The  o t h e r s e r i e s (B) r e c e i v e d o n l y I s o c h r y s i s sp. f o r t h e f i r s t two  weeks, and then was f e d on t h e same regime a s s e r i e s A.  102  Galorimetry Introduction The importance o f copepods i n t h e f o o d c h a i n depends t o a g r e a t e x t e n t on t h e i r l i p i d F i s h e r 1962; a l . 1971,  c o n t e n t , which has been e x t e n s i v e l y a n a l y s e d  L i t t l e p a g e 1964;  1972,  1974;  L i n f o r d 1965;  W i s s i n g e t a l . 1973).  Ackman e t a l . 1970;  et  The l i p i d c o n t e n t o f cope-  pods c o n s i s t s . ; . l a r g e l y of wax e s t e r s ( N e v e n z e l 1970;  Lee e t a l . 1971)  i n many s p e c i e s , t h e t o t a l l i p i d c o n t e n t shows an a n n u a l 1962;  Lee  (e.g.  and  cycle,(Fisher  Gomita e t a l . 1966). The s i z e d i f f e r e n c e between Calanus plumchrus and C. m a r s h a l l a e  sug-  g e s t s t h a t t h e i r f o o d v a l u e ( e x p r e s s e d as a f u n c t i o n of l i p i d c o n t e n t ) i s different.  A p l a n k t i v o r e would need t o g r a z e a l a r g e r number o f  m a r s h a l l a e than G_. plumchrus t o o b t a i n an e q u i v a l e n t r a t i o n . of r e s p o n s e has been demonstrated  for of  L e B r a s s e u r I969) •  chum s a l -  These salmon s p e c i e s showed b o t h a p r e f e r e n c e  p r e y i n t h e s i z e range 2.5-4.5 mm smaller prey.  This type  f o r j u v e n i l e salmon f e e d i n g on t h r e e  s i z e ranges of p r e y ( p i n k salmon: P a r s o n s and L e B r a s s e u r 1970; mon:  Calanus  i n t o t a l l e n g t h and an  avoidance  The p r e f e r r e d l e n g t h range u n f o r t u n a t e l y i n c l u d e s b o t h  C. plumchrus and C. m a r s h a l l a e ; however, t h e g e n e r a l p a t t e r n o f t h e s e r e s u l t s s u p p o r t s my c o n t e n t i o n t h a t a s h i f t t o a p r e y s p e c i e s o f s m a l l e r average s i z e may  be d e t r i m e n t a l .  L e B r a s s e u r (I969) d i d n o t f i n d any d i f f e r e n c e i n f o o d v a l u e between t h e d i f f e r e n t s i z e ranges of p r e y .  However, he judged f o o d v a l u e on t h e  b a s i s o f observed growth i n f i s h which were f e d on t h r e e s i z e ranges food i n a h i g h l y a r t i f i c i a l s i t u a t i o n .  of  I n t h e f i e l d , t h e major e f f e c t o f  a s h i f t i n p r e y s i z e might be t o i n c r e a s e t h e amount o f energy  expended  103  In g r a z i n g , and t o i n c r e a s e t h e g r a z i n g t i m e n e c e s s a r y t o o b t a i n an adequate r a t i o n .  I n c r e a s i n g t h e s e f a c t o r s c o u l d c o n c e i v a b l y push a p r e d a -  t o r y s p e c i e s c l o s e r t o a s i t u a t i o n i n which f u l l t i m e g r a z i n g was n o t enough t o meet t h e m e t a b o l i c  demands o f maintenance and normal growth.  The s i z e d i f f e r e n c e s between t h e l a t e r c o p e p o d i t e s t a g e s o f t h e two s p e c i e s might a l s o n e c e s s i t a t e a s h i f t i n t h e f e e d i n g s t r a t e g y o f p r e d a tors.  Leong and O'Gonnell (i960)  show t h a t t h e n o r t h e r n anchovy f i l t e r  f e e d s on s m a l l c p a r t i c l e s b u t uses a b i t i n g a t t a c k on l a r g e p a r t i c l e s . O ' C o n n e l l (1972) f u r t h e r s u g g e s t s t h a t f i l t e r f e e d i n g a l o n e may n o t be s u f f i c i e n t t o p r o v i d e t h e f i s h w i t h i t s r e q u i r e d r a t i o n , and t h a t l a r g e r prey are a necessary p a r t o f the d i e t . I n e i t h e r case, a l a r g e - s c a l e s h i f t i n t h e p o p u l a t i o n s i z e s o f G_. plumchrus and G. m a r s h a l l a e  may a f f e c t t h e s u r v i v a l o f a p r e d a t o r  i s f o r c e d t o s h i f t t o t h e s m a l l e r copepod a s a f o o d s o u r c e .  which  As a f i r s t  approach t o t h e problem o f e s t i m a t i n g p o s s i b l e e f f e c t s o f such a s h i f t , t h e c a l o r i f i c c o n t e n t o f specimens o f t h e two s p e c i e s was d e t e r m i n e d . Measurements o f c a l o r i f i c v a l u e a r e more s u i t a b l e than measurements of l i p i d w e i g h t .  Methods f o r e s t i m a t i n g t o t a l l i p i d s by e x t r a c t i o n rt-.qu  r e q u i r e l a r g e r numbers o f a n i m a l s t h a n c a l o r i m e t r y and a r e a l s o more s u b j e c t t o e r r o r due t o t h e d i f f i c u l t i e s o f e x t r a c t i n g t o t a l l i p i d s ( L i n f o r d 1965). R e s u l t s o b t a i n e d by t h e c a l o r i m e t r y method a r e e x p r e s s e d a s " c a l o r i e s l i b e r a t e d p e r mg f r e e z e - d r i e d w e i g h t " . n e g l i g i b l e (e.g. Wissing  The r e s i d u e a f t e r b u r n i n g i s  e t a l . 1973)» and hence t h e r e s u l t s approximate  u n i t s o f " c a l o r i e s l i b e r a t e d p e r mg a s h - f r e e d r y w e i g h t " .  Carbon con-  t e n t may be e x p r e s s e d i n terms o f c a l o r i f i c v a l u e ( r = O.98) by a s i m p l e  1C4  l i n e a r r e l a t i o n s h i p (Eon 2: P i a t t e t a l . 1969). f a c i l i t a t i n g  comparison  with values reported i n the l i t e r a t u r e .  cal/mg d r y wt = 1351  + 106(%C) - Zl.Z(%  ash)  (Eqn 2)  Procedure Samples o f c o p e p o d i t e s o f b o t h s p e c i e s were o b t a i n e d i n t h e f i e l d and r e t u r n e d a l i v e t o t h e l a b o r a t o r y i n i s o t h e r m s .  In the labora-  t o r y , specimens o f each s p e c i e s were s e l e c t e d a t random, p l a c e d b r i e f l y on a p i e c e o f b l o t t i n g p a p e r t o remove excess water, and i m m e d i a t e l y f r o zen.  The f r o z e n samples were l a t e r f r e e z e - d r i e d f o r t w e n t y - f o u r h o u r s  and t h e i r c a l o r i f i c v a l u e s determined u s i n g a P h i l l i p s o n Microbomb C a l o r i m e t e r (Comita and S c h i n d l e r I963)•  Due t o t h e minimum weight r e q u i r e d  f o r a n a l y s i s , a p p r o x i m a t e l y f i v e C a l a n u s plumchrus o r t e n C. m a r s h a l l a e had t o be combined f o r each sample. weight ( c a . 3-5  mg)•  T h i s y i e l d e d samples o f comparable  105  Results Distribution Data from h o r i z o n t a l tows indicates that there i s almost 100% v e r t i c a l overlap i n the populations of the two species when they are overwintering ( F i g . 10).  During hatching and development of the next  generation, the young stages of both species overlap i n near surface water.  Very young stages ( <Gopepodite III) can not be r e a d i l y t o l d  apart; however, there i s no bimodal structure to the v e r t i c a l d i s t r i b u t i o n of young Galanus that might suggest v e r t i c a l separation of the populations at t h i s time (Gardner 1972).  Feeding The second maxillae of Galanus plumchrus zones (Fig. 11; Table XV).  Table XV:  Zone  can be divided into three  Zone 1 takes up most of the f i l t e r i n g surface  F i l t r a t i o n zone analysis of the second maxillae of Galanus plumchrus and G. marshallae. Area i s expressed as per cent of t o t a l f i l t e r i n g area + one standard deviation.  G. plumchrus  C. marshallae  % of t o t a l area  Mean ISD (um)  % of. t o t a l area  Mean ISD (ym)  1  74.2 + 4.7  2.4 + 0.4  68.9 + 6.4  5-3 ± 0.8  2  20.8 + 4.7  4.2 + 0 . 9  13-0 + 5.0  3.9 + 0.5  5.0(approx.) 9-3 ± 2.3  3 4. Total  3.0  (approx.) 11.4 + 1.3  >- 15.0 •+ 5.2  2 area (mm )  0.450 +  0.103  0.107  12.4 + 1.1  + 0.019  106a  F i g u r e 10:  V e r t i c a l d i s t r i b u t i o n of Calanus plumchrus and C. m a r s h a l l a e d u r i n g o v e r w i n t e r i n g .  NOV 7 3 (0200)  JAN '73 (1800)  10?a  F i g u r e 11:  Second m a x i l l a e o f C a l a n u s plumchrus and C. m a r s h a l l a e . M a j o r d i s t i n c t f i l t e r i n g zones a r e shown i n o u t l i n e . The one " i n d i s t i n c t " zone f o r each s p e c i e s i s n o t shown ( s e e t e x t for description).  107b  OJ  C  108  and has the smallest mesh size.  Zone 2 consists of a f a i r l y d i s t i n c t  leading edge composed of the three or four d i s t a l setae. Zone t ^ r i s not sharply defined. I t consists of a small number of heavy, strong setae found evenly dispersed along the maxilla.  These setae have a very  coarse mesh size and are so oriented that they cut across several of the setae of Zones 1 and 2.  The effective area of f i l t r a t i o n of these setae  could not be measured accurately, but was estimated to be 5% of the t o t a l effective f i l t e r i n g area. Calanus marshallae has four zones on the f i l t e r i n g surface; however, the distinction between the two finest zones and the two coarsest zones i s minimal, and they intergrade more completely than the zones of Calanus plumchrus.  Zone 2, the withstheesmallest LSD's, covers only the proximal  edge of the f i l t e r i n g surface. Zone h constitutes the d i s t a l edge,of t l . and zone 1, as i n C. plumchrus, i s the largest zone and constitutes the central area of the f i l t e r i n g surface. Zone 3 i s analogous to zone 3 of Calanus plumchrus, and i s estimated to take up Jfo of the f i l t e r i n g sur~a face. When the curves of f i l t e r i n g efficiency are calculated and plotted (Fig. 12), i t i s obvious that Calanus plumchrus, despite having the larger body size, i s better equipped for f i l t e r i n g smalllparticles than i s G. marshallae. The curve for C. marshallae shows a plateau at 70% efficiency. This plateau i s caused by the separation between the regions of fine and coarse mesh. The actual f i l t e r i n g areas for the maxillae of the two species (Table XV) show that Calanus plumchrus has about four times the f i l t e r i n g area of C. marshallae•  109a  F i g u r e 12:  F i l t e r i n g e f f i c i e n c y curveslfor.gCalanus plumchrus and Galanus m a r s h a l l a e .  109b  Diameter (pm)  110  Rearing and breeding Galanus marshallae could not be bred i n the laboratory. Woodhouse (1971) was also unsuccessful i n breeding G. marshallae, although he did  obtain f e r t i l i z a t i o n  i n one i s o l a t e d instance.  Galanus marshallae  females returned to the laboratory from the f i e l d neither produced nor layed eggs, even though they could be kept i n a controlled  environment  chamber f o r long periods of time without t h e i r condition noticeably deteriorating . The l i f e h i s t o r y of Galanus plumchrus i s such that ovigerous females are  r e a d i l y available i n January and February (Gardner 1972).  Galanus  plumchrus females brought to the laboratory i n an ovigerous condition shed t h e i r eggs and the eggs developed.  Development through the t h i r d  copepodite stage (CIIl) was common, but development to the f i f t h copepodite (CV) was unusual.  Using development times obtained i n the laboratory rT  (Table XVl),aand i n s e r t i n g them into Winberg's (1956) equation (Eqn 3 ) , rates were calculated f o r growth between successive stages (NB: naupliar stages were grouped) and f o r o v e r a l l growth from both egg and f i r s t copepodite to GV (Tables XVI,  where:  %AW  XVIl).  i s the per cent increment i n wet weight per day  W^ and Wg are the weights of the stages of the organism at the beginning and end of the growth i n t e r v a l t  i s the time i n days to go. ifrom stage 1 to stage 2  Ill  Development t i m e s and growth r a t e s o f C a l a n u s plumchrus a t 8 C. Wet w e i g h t s a r e d e r i v e d f r o m measurements o f f i e l d samples t a k e n c o n c u r r e n t l y w i t h t h e l a b o r a t o r y s e r i e s . Times a r e based on 25 specimens f o r t h e young s t a g e s , and on 10 specimens f o r t h e o l d e s t s t a g e s ( o l d e r t h a n t h e second c o p e p o d i t e ) .  Table XVI:  Series  A  B  Stage  Mean t i m e to f i r s t appearance (days)  Development t i m e between s u c c e s s i v e s t a g e s (days)  Mean wet weight (mg)  %AW/day  CI  7.0 60.8  53-8  0.15  9-5  CII  73.8  13.0  0.28  4.9  cm  78.4  4.6  0.52  CIV  87.8  9.4  CV  110.0  22.2  1-39 3.02  14.4 11.0  Egg  10.0  CI  53-2 55-6  43.2 2.4  0.15  0.28  29.8  3-7  0.52  18.2  CIV  59-3 68.3  9.0  GV  86.5  18.2  1.39 3.02  11.5 3.0  Egg  CII GUI  0.003*  2-5  0.003* 6-9,  * D a t a d e r i v e d f r o m F u l t o n (1973)  Table XVII:  O v e r a l l growth r a t e s f o r C a l a n u s plumchrus r e a r e d i n t h e l a b o r a t o r y , e x p r e s s e d as % change i n w e i g h t p e r d a y .  Series  C I t o CV  A  6.3  B  9.4  Egg t o CV  6.9 9.4  112  Calorimetry S e a s o n a l v a r i a t i o n i n c a l o r i f i c v a l u e s of e i t h e r s p e c i e s c o u l d n o t be d e t e c t e d .  The average c a l o r i f i c v a l u e s ( T a b l e X V I I l ) ^ s h o w t h a t  there i s l i t t l e d i f f e r e n c e i n food value (expressed i n calories/mg)  be-  tween t h e two s p e c i e s ; however, t h e d i f f e r e n c e i n r e l a t i v e s i z e o f C a l a n u s plumchrus and C a l a n u s m a r s h a l l a e r e s u l t s i n a l a r g e d i f f e r e n c e i n c a l o r i f i c value per  individual.  Table X V I I I :  Average c a l o r i f i c v a l u e p e r u n i t d r y weight and i n d i v i d u a l (+ one s t a n d a r d d e v i a t i o n ) .  Cal/mg f r e e z e - d r i e d wt  Calories/copepod  C. plumchrus  5.92  +  0.70  3.08  C.  6.16  + 0.-6-1-- •  1.23  marshallae  per  (approx.)  113  Discussion The f i e l d d a t a i n d i c a t e t h a t Galanus plumchrus and G_. m a r s h a l l a e have the  same o v e r w i n t e r i n g ' d i s t r i b u t i o n p a t t e r n a t Geo 17^8.  There i s no  e v i d e n c e f o r p h y s i c a l s e p a r a t i o n o f t h e two s p e c i e s a t t h i s o r any o t h e r t i m e o f t h e y e a r f o r which d a t a a r e a v a i l a b l e .  F r o s t (1974) d e s c r i b e s  Galanus m a r s h a l l a e as o c c u r r i n g n o r t h o f 40° n o r t h l a t i t u d e i n c o a s t a l a, and n e a r s h o r e waters of t h e e a s t e r n N o r t h P a c i f i c and B e r i n g Sea. nus plumchrus  Gala-  i s more w i d e l y d i s t r i b u t e d i n t h e N o r t h P a c i f i c ( G e y n r i k h  I968), b u t i s a p p a r e n t l y found i n a l l o f t h e a r e a s from which m a r s h a l l a e has been r e p o r t e d .  Galanus  I t i s p r o b a b l e t h a t t h e two s p e c i e s co-  e x i s t t h r o u g h o u t t h e range o f Galanus. m a r s h a l l a e , a l t h o u g h t h e r e i s l i t t l e d a t a on t h e s i m u l t a n e o u s d i s t r i b u t i o n o f each s p e c i e s .  Given the f a c t  t  t h a t t h e y c o - e x i s t , we can i n v e s t i g a t e e c o l o g i c a l f a c t o r s which a c t t o r e d u c e t h e p o s s i b i l i t y o f c o m p e t i t i o n between them. The major e c o l o g i c a l d i f f e r e n c e between t h e s p e c i e s i s i n t h e i r a b i l i t y t o f i l t e r p a r t i c l e s out of t h e s u r r o u n d i n g w a t e r . the  A n a l y s i s of  p r i m a r y f i l t e r i n g appendage, t h e second m a x i l l a , shows s i m i l a r i t i e s  i n g e n e r a l s t r u c t u r e between t h e two s p e c i e s , but d i f f e r e n c e s i n f i n e s t r u c t u r e which a f f e c t t h e e f f i c i e n c y w i t h which s m a l l p a r t i c l e s can be removed f r o m the water.  C a l a n u s plumchrus  can t h e o r e t i c a l l y e x p l o i t t h e  s i z e range of p a r t i c l e s of d i a m e t e r 3 7 ym a l m o s t w i t h o u t c o m p e t i t i o n from -  G. m a r s h a l l a e , and m a i n t a i n s an advantage  in filtering ability for parti-  c l e s between 7 and 12'>ym i n d i a m e t e r . P a r t i c l e s o f l e s s t h a n 12 ym studied.  i n d i a m e t e r have n o t been v e r y w e l l  They c o n s t i t u t e t h e l o w e r range o f t h e n a n o p l a n k t o n (2-20 um i n  d i a m e t e r : P a r s o n s and T a k a h a s h i 1973)> and t h e r e a r e i n d i c a t i o n s t h a t  114  t h e y make up a l a r g e p o r t i o n o f t h e p a r t i c u l a t e o r g a n i c biomass i n t h e marine ecosystem.  P a r s o n s (1972) c o n c l u d e s t h a t i n March and A p r i l t h e  p r i n c i p a l p r i m a r y p r o d u c e r s i n t h e s u b a r c t i c P a c i f i c Ocean a r e nanoplankton  i n t h e range 8-16  pm i n d i a m e t e r .  He a l s o shows secondary peaks o f  abundance f o r p a r t i c l e s of 4 pm i n d i a m e t e r . a 5 pm f i l t e r r e t a i n e d as l i t t l e as 42%  Anderson  of the organic p a r t i c u l a t e s i n  water c o l l e c t e d o f f t h e Oregon and Washington et  al.  (I960) found t h a t i n summer, 75%  (1965'). found t h a t  coasts, while M c A l l i s t e r  o f t h e c h l o r o p h y l l 'a' a t ocean  weather s t a t i o n "Papa" w i l l p a s s t h r o u g h a 10 ym f i l t e r .  Kitchen et a l .  (I975)f a l s o w o r k i n g o f f t h e Oregon c o a s t , measured t h e numbers of p a r t i c u l a t e s i n v a r i o u s s i z e c l a s s e s i n t h e range from 8-105  ym i n d i a m e t e r .  They o f t e n found t h e peak biomass t o be a t t h e l o w e r l i m i t o f t h e i r  size  range, b u t d i d n o t l o o k a t t h e biomass d i s t r i b u t i o n o f p a r t i c l e s o f d i a m e t e r l e s s than 8  pm.  L o c a l l y , Pandyan (1971) examined t h e volume of p a r t i c u l a t e m a t t e r a v a i l a b l e a t v a r i o u s d e p t h s i n v a r i o u s seasons i n Howe Sound, a body o f water which opens d i r e c t l y i n t o t h e S t r a i t of G e o r g i a .  She found t h a t  p a r t i c l e s i n near bottom water were g e n e r a l l y between 3-6  and 14.5  5 i n d i a m e t e r , and t h a t t h e t o t a l volume ranged from 10  pm  7 t o 10  c u b i c pm  p e r ml. D e s p i t e e v i d e n c e o f t h e importance o f s m a l l p a r t i c l e s t o t h e t o t a l biomass, t h e y a r e n o t r e g u l a r l y i n c l u d e d i n b i o l o g i c a l s u r v e y s and  littl-  i s known about t h e t y p e s of p a r t i c l e which c o n t r i b u t e t o t h e s m a l l e r nanoplankton.  Kitchen et a l .  (.1^975) found a h i g h c o r r e l a t i o n between  p a r t i c u l a t e o r g a n i c carbon and c h l o r o p h y l l ' a , s u g g e s t i n g t h a t much o f 1  the and  p a r t i c u l a t e o r g a n i c biomass i s p h y t o p l a n k t o n i c .  In a d d i t i o n , S e k i  115  and Kennedy (1969) r e p o r t t h a t t h e l e v e l o f marine b a c t e r i a and o t h e r he.terotrophs i n t h e S t r a i t o f G e o r g i a i s g e n e r a l l y s u f f i c i e n t f o r maintenance o f t h e z o o p l a n k t o n and i s c o n s e q u e n t l y an i m p o r t a n t component o f t h e o r g a n i c p a r t i c u l a t e biomass.  However, t h e o n l y comprehensive  examina-  t i o n o f t h e c o m p o s i t i o n o f t h e l o c a l p h y t o p l a n k t o n which i n c l u d e d v e r y s m a l l p a r t i c l e s i s t h e work by Buchanan (1966) i n I n d i a n Arm, a f j o r d t y p e i n l e t near Vancouver. U n f o r t u n a t e l y , Buchanan was n o t d i r e c t l y concerned w i t h t h e d i s t r i b u t i o n o f d i f f e r e n t s i z e classes,,and r e p o r t s t h e s i z e s o f s p e c i e s o n l y a s an a d j u n c t t o t h e i r d e s c r i p t i o n and o n l y f o r c e r t a i n s p e c i e s . found t h a t a l l o f t h e predominant were i n t h e n a n o p l a n k t o n  Buchanan  p l a n k t o n i c h e t e r o t r o p h s i n I n d i a n Arm  s i z e range ( d e f i n e d by Buchanan a s 5-60 ym i n  d i a m e t e r , c f . P a r s o n s and T a k a h a s h i 1973) °r s m a l l e r .  He  encountered  336 s p e c i e s , o f which he c o n s i d e r e d 88 t o be o f major e c o l o g i c a l  impor-  tance.  I n many groups, t h e major s p e c i e s were l e s s than 10 ym i n d i a -  meter.  F o r example, i n t h e Ghrysophyceae, which Buchanan c o n s i d e r e d im-  p o r t a n t and connected w i t h n u t r i e n t r e g e n e r a t i o n , a t l e a s t 6 o f t h e 15 s p e c i e s were under 10 ym i n d i a m e t e r .  S i m i l a r l y , a t l e a s t 50% o f t h e  major Haptophyceae were s p e c i e s under 6 un, and b o t h major were under 5 ym.  Ghlorophyceae  These d a t a g e n e r a l l y s u p p o r t t h e h y p o t h e s i s t h a t v e r y  s m a l l ( i . e . l e s s t h a n 12 um i n d i a m e t e r ) p a r t i c l e s a r e an i m p o r t a n t component o f t h e l i v i n g o r g a n i c p a r t i c u l a t e biomass o f t h e S t r a i t o f G e o r g i a . The n o n - l i v i n g f r a c t i o n o f t h e p a r t i c u l a t e m a t t e r must a l s o be cons i d e r e d as a n u t r i e n t source.  Non-living organic p a r t i c u l a t e material  i s p r e s e n t i n l e v e l s much h i g h e r than t h e l e v e l o f l i v i n g p a r t i c u l a t e s ( R i l e y 1970), b u t has been s t u d i e d l e s s .  I t s n u t r i t i v e v a l u e has n o t  116  been e s t a b l i s h e d , but p r o b a b l y v a r i e s d e p e n d i n g on i t s s o u r c e and of degradation,  and  degree  on t h e e f f i c i e n c y o f t h e organism u t i l i z i n g i t .  In-  g e s t i o n o f s m a l l o r g a n i c p a r t i c u l a t e s has been demonstrated f o r a number o f copepod s p e c i e s .  C o r n e r e t al.9(1.974) f o u n d t h a t o v e r w i n t e r i n g C a l a lev  nus h e l g o l a n d i c u s c o u l d n o t o b t a i n s u f f i c i e n t n u t r i t i o n f r o m n a t u r a l l e v e l s o f suspended m a t t e r i n sea w a t e r . e f f i c i e n t l y on dead b a r n a c l e n a u p l i i .  However, t h e s p e c i e s c o u l d f e e d  S i m i l a r l y , Paffenh'6f e r r a n d  Strick-  l a n d (1970) showed t h a t w h i l e C. h e l g o l a n d i c u s d i d n o t f e e d on " n a t u r a l i t c  d e t r i t u s " ( e . g . u n s t r u c t u r e d m a t e r i a l such as o r g a n i c a g g r e g a t e s ) ,  c o u l d f e e d r e a d i l y on dead d i a t o m s and would a l s o i n g e s t p o l y s t y r e n e balls.  F u r t h e r m o r e , P o u l e t (1976) has e s t a b l i s h e d t h a t n o n - l i v i n g o r g a n i c  p a r t i c u l a t e s are a b a s i c food f o r Pseudocalanus minutus. In s p i t e of the a v a i l a b i l i t y of s m a l l organic p a r t i c u l a t e s , i t i s commonly assumed t h a t copepods w i l l s e l e c t i v e l y f e e d on l a r g e p a r t i c l e s when t h e y a r e a v a i l a b l e ( e . g . M u l l i n 1963; g r a v e and Geen 1970). o r i e n t e d and  i n v o l v e exposing  suggests  Har-  Most e x p e r i m e n t s on s i z e s e l e c t i v i t y a r e l a b o r a t o r y t h e organism t o c o n c e n t r a t i o n s o f f o o d much  h i g h e r than a r e found i n t h e environment. 1973)  Richman and Rogers 1969;  P e t i p a (1965, c i t e d by M a r s h a l l  t h a t when f e e d i n g a c t i v e l y i n t h e sea, a copepod i s more  l i k e l y to feed i n d i s c r i m i n a t e l y .  M a r s h a l l (1973)1 i n an e x t e n s i v e  o f t h e l i t e r a t u r e c o n c e r n i n g f e e d i n g i n copepods, c o n c l u d e s  that  review  although  m a r i n e copepods o f t e n s e l e c t f o r l a r g e r c e l l s i z e s when g r a z i n g , t h e i r p r e f e r e n c e s a r e n o t f i x e d but can change t o t a k e advantage o f a v a i l a b l e food.  Thus t h e a p p r o x i m a t i o n  (Boyd 1976)  of the f i l t e r i n g net t o a "leaky s i e v e "  i s perhaps t h e most r e a l i s t i c approach t o t a k e .  The p r e s e n c e of a l a r g e biomass of p a r t i c l e s o f d i a m e t e r  less  than  117  12 ym i n t h e S t r a i t o f G e o r g i a , and t h e a b i l i t y o f C. plumchrus p a r t i c l e s as s m a l l as 2.0  ym i n d i a m e t e r , s u g g e s t s t h a t Galanus  to  filter  plumchrus  can n o t vonly g r a z e on a p o r t i o n o f t h e p a r t i c u l a t e biomass u n a v a i l a b l e to  G. m a r s h a l l a e , h u t t h a t i t can o b t a i n a l a r g e p r o p o r t i o n of i t s r a t i o n  from s m a l l o r g a n i c p a r t i c u l a t e s . Galanus plumchrus  will  a l s o be a b l e t o i n g e s t s m a l l i n o r g a n i c p a r t i -  14 culates.  V y s h k v a r t s e v a and Gutel'makher  (1971) a l l o w e d G  -labelled  t e r i a t o adsorb onto c l a y p a r t i c l e s up t o 18 ym i n d i a m e t e r , and  bac-  then  a l l o w e d Galanus g l a c i a l i s (= C. m a r s h a l l a e ? , see appendix A) t o g r a z e t h e mixture.  Galanus g l a c i a l i s was a b l e t o i n g e s t t h e p a r t i c l e s and assimi?-  l a t e the organic matter.  The r i v e r s d r a i n i n g i n t o t h e S t r a i t of G e o r g i a  are a r i c h source of i n o r g a n i c p a r t i c u l a t e s .  S e k i e t a l . (I969) examined  the c o n t r i b u t i o n to the S t r a i t of Georgia of p a r t i c u l a t e m a t e r i a l by t h e Nanaimo R i v e r .  carried  They found t h a t i n l a t e w i n t e r , more t h a n 90%  of  t h e p a r t i c u l a t e m a t t e r i n b o t h t h e r i v e r and t h e e s t u a r y c o n s i s t e d o f p a r t i c l e s o f l e s s than 4 ym i n d i a m e t e r .  Most o f t h i s m a t e r i a l was  g a n i c and c a p a b l e o f a d s o r b i n g o r g a n i c m a t e r i a l .  T h i s t y p e o f sedimen-  t a r y m a t e r i a l c o u l d be g r a z e d by Galanus plumchrus Thus, Galanus plumchrus  b u t n o t be C. m a r s h a l l a e .  i s equipped t o f i l t e r a w i d e r and more d i -  v e r s e spectrum o f p a r t i c u l a t e m a t t e r t h a n i s Galanus m a r s h a l l a e . of 2.0  t h e a b i l i t y of Galanus plumchrus ym,  inor-  Because  t o h a n d l e p a r t i c l e s as s m a l l as  i t might a l s o be a b l e t o f e e d on more d i f f u s e suspended m a t e r i a l  such as d e t r i t u s .  D e t r i t a l m a t e r i a l was u n a v a i l a b l e t o Galanus h e l g o -  l a n d i c u s ( C o r n e r e t a l . 19?4); however, t h e s m a l l e s t i n t e r - s e t u l e d i s t a n c e o f G. h e l g o l a n d i c u s i s r e p o r t e d t o be 5 ym Gutel'makher  1971)•  ( V y s h k v a r t s e v a and  T h i s would make i t l e s s e f f i c i e n t t h a n C a l a n u s  118  plumchrus i n t h e h a n d l i n g o f d i f f u s e m a t e r i a l .  Such m a t e r i a l might be  i m p o r t a n t i n m a i n t a i n i n g t h e metabolism o f C a l a n u s plumchrus d u r i n g o v e r w i n t e r i n g , b u t t h e r e i s no d a t a a t t h e moment t o s u b s t a n t i a t e t h i s hypothesis. In a d d i t i o n . . t o a s u p e r i o r a b i l i t y  i n the handling of small p a r t i c l e s ,  C a l a n u s plumchrus i s a l s o equipped t o f i l t e r more w a t e r y p e r u n i t weight than i s G. m a r s h a l l a e •  The f i l t e r i n g s u r f a c e o f t h e second m a x i l l a o f  C. plumchrus has an a r e a o f a p p r o x i m a t e l y 0.4-5 mm . The t o t a l filtering  s u r f a c e can be e s t i m a t e d by t h e t o t a l f i l t e r i n g  two second m a x i l l a e .  effective  surface of the  Based on t h e second m a x i l l a e , C a l a n u s plumchrus 2  has an e f f e c t i v e f i l t e r i n g a r e a o f a p p r o x i m a t e l y 0.90 mm , and C. mar2  s h a l l a e has an e f f e c t i v e f i l t e r i n g a r e a o f a p p r o x i m a t e l y 0.21 mm , o r  2J% o f t h e a r e a a v a i l a b l e t o C. plumchrus.  However, C a l a n u s plumchrus  (CV) has a mean wet w e i g h t o f 3-0 mg as compared w i t h 1.2 mg f o r C. mars h a l l a e (CV) (Gardner unpub.). Suppose we d e f i n e a rough m e c h a n i c a l e f f i c i e n c y f a c t o r (F ) a s t h e r a t i o between e f f e c t i v e f i l t e r i n g s u r f a c e and mean wet w e i g h t .  This  y i e l d s a f i g u r e representing the area of f i l t e f i h g r s u r f a c e f p e r unit of body w e i g h t . 0.3,  F o r t h e f i f t h c o p e p o d i t e o f Calanusnplumchrus, t h e F^ i s  w h i l e f o r t h e same s t a g e o f C. m a r s h a l l a e i t i s 0.2.  Furthermore,  s i n c e C. plumchrus i s l a r g e r than G. m a r s h a l l a e , i t s h o u l d have a l o w e r m e t a b o l i c r a t e , and hence have a l o w e r energy r e q u i r e m e n t p e r u n i t body weight ( e . g . Hoar I966; I k e d a 1970).  This hypothesis i s not s t r i c t l y  a p p l i c a b l e s i n c e r e s p i r a t i o n i n copepods can v a r y s e a s o n a l l y and r e g i o n a l l y as w e l l as w i t h s i z e .  F o r two c l o s e l y r e l a t e d s p e c i e s from t h e same  r e g i o n , however, t h e r e l a t i o n s h i p between w e i g h t and m e t a b o l i s m s h o u l d be  119  approximately  l i n e a r (Gonover 1959)•  U s i n g a d i f f e r e n t approach, P a r s o n s  and S e k i (1970) r e a c h e d a s i m i l a r c o n c l u s i o n .  They used d a t a from v a r i -  ous s o u r c e s t o show t h a t t h e l a r g e r t h e copepod, t h e s m a l l e r t h e phytoplankton All  population necessary  t o support  total  growth.  of t h e above f a c t o r s suggest t h a t Galanus plumchrus can n o t  only  f i l t e r a v a i l a b l e f o o d r e s o u r c e s more e f f i c i e n t l y , but c a n t o b t a i n an adeq u a t e r a t i o n more r e a d i l y , t h a n C. m a r s h a l l a e  even under c o n d i t i o n s where  b o t h s p e c i e s can t r a p t h e a v a i l a b l e p a r t i c l e s w i t h 100% In  efficiency.  d e s c r i b i n g t h e f e e d i n g c a p a b i l i t i e s o f G a l a n u s plumchrus and  marshallae , 1  C.  I have d i s r e g a r d e d t h r e e i m p o r t a n t v a r i a b l e s : t h e r a t e a t  w h i c h water i s • p a s s e d o v e r t h e mouth p a r t s , t h e a s s i m i l a t i o n  efficiency  o f t h e copepods and t h e s e a s o n a l f l u c t u a t i o n s i n t h e m e t a b o l i c c r a t e o f t t h e copepods. my  The  e f f e c t s of these v a r i a b l e s should not adversely a f f e c t  c o n c l u s i o n s , however. I have suggested t h a t m e t a b o l i c r a t e and  linearly related.  s i z e are  approximately  There c o u l d s t i l l be s e a s o n a l f l u c t u a t i o n s i n meta-  b o l i s m t h a t would a f f e c t t h e r e l a t i o n s h i p between the.two s p e c i e s . Measurements o f t h e m e t a b o l i c r a t e o f Galanus plumchrus were n o t d u c i b l e due t o l i m i t a t i o n s i n equipment.  repro-  I t has been s u g g e s t e d , however,  t h a t C. plumchrus o v e r w i n t e r s i n a s t a t e s i m i l a r t o d i a p a u s e ( G a r d n e r 1972).  The  copepod has been s t a t e d t o r e d u c e o r cease f e e d i n g d u r i n g  t h i s p e r i o d (Pandyan 1971), but i n l i g h t o f i t s a b i l i t y t o g r a z e of a s i z e o f t e n d i s r e g a r d e d i n f e e d i n g experiments, some f e e d i n g s t i l l goes on. p e r i o d s i n f i l t e r e d (0.45  um)  particles  i t i s possible that  Galanus plumchrus can s u r v i v e f o r l o n g sea water (Gardner 1972); however, b a c t e r i a  g r o w i n g i n t h e sea water a f t e r f i l t r a t i o n c o u l d become a v a i l a b l e t o  G.  120  plumchrus by a g g r e g a t i n g t h e water.  i n t o p a r t i c l e s l a r g e enough t o be f i l t e r e d f r o m  Thus i t i s i m p o s s i b l e t o s t a t e t h a t f e e d i n g ceases  during overwintering, although  completely  i t i s undoubtedly very.much reduced f r o m  f e e d i n g d u r i n g o t h e r t i m e s of t h e  year.  S i m i l a r s t u d i e s have n o t been c a r r i e d out on Galanus m a r s h a l l a e  in  t h e S t r a i t of G e o r g i a ; however, Borgmann (1973b) measured oxygen consumpt i o n of Galanus g l a c i a l i s (= m a r s h a l l a e ) b e r 1972  i n l o c a l waters.  c o l l e c t e d from August t o Novem-  He d i d not n o t e any change i n t h e r e s p i r a t i o n  r a t e o f C. g l a c i a l i s over t h i s t i m e p e r i o d , and t h e r e s p i r a t o r y r a t e s which he o b t a i n e d c o r r e s p o n d  v e r y w e l l w i t h t h e r a t e o b t a i n e d by I k e d a  (1970) f o r Galanus g l a c i a l i s (= marshallae?') August i n t h e B e r i n g Sea.  c a p t u r e d between June and  Borgmann ( p e r s . comm.) u n s u c c e s s f u l l y attemp-  t e d s i m i l a r measurements on Galanus plumchrus c a p t u r e d  i n the e a r l y f a l l .  These d a t a support t h e assumption t h a t t h e o v e r w i n t e r i n g metabolism o f Galanus m a r s h a l l a e  w i l l n o t l i k e l y drop below t h a t of C.  plumchrus .  Thus energy b e n e f i t s o b t a i n e d by Galanus plumchrus due t o i t s a b i l i t y t o g r a z e more e f f i c i e n t l y w i l l not be l o s t i n t h e maintenance o f a higher metabolic r a t e . The  e f f i c i e n c y w i t h which f o o d i s a s s i m i l a t e d has a l s o n o t been  e s t a b l i s h e d f o r e i t h e r Galanus plumchrus or G. m a r s h a l l a e .  However,  t h e r e i s no b a s i s f o r assuming t h a t a s s i m i l a t i o n i n e i t h e r o f t h e s e species i s s i g n i f i c a n t l y higher than i n the other.  two  Assimilation e f f i -  c i e n c i e s i n copepods i n g e n e r a l appear t o be h i g h , but a r e v a r i a b l e within species.  C o r n e r e t a l . (1967), f o r example, r e p o r t a g r o s s  e f f i c i e n c y i n a d u l t Galanus f i n m a r c h i c u s o f 34%,  feeding  w h i l e M a r s h a l l and  Orr  (1955a) suggest an a s s i m i l a t i o n e f f i c i e n c y of 90% f o r t h e same s p e c i e s .  121  I n a d d i t i o n , Gonover (1966a, b) c a l c u l a t e d t h e a s s i m i l a t i o n f o r C a l a n u s h y p e r b o r e u s and o b t a i n e d v a l u e s o f 55% t o 80%,  efficiencies dependent on  t h e degree of s a t i a t i o n . F i l t r a t i o n r a t e s a r e a l s o unrecorded f o r e i t h e r s p e c i e s .  However,  C a l a n u s plumchrus i s m e c h a n i c a l l y more e f f i c i e n t a t o b t a i n i n g n u t r i t i o n , and s h o u l d be a b l e t o f i l t e r water a t a l o w e r r a t e w h i l e s t i l l t h e same r a t i o n p e r u n i t body w e i g h t .  obtaining  Thus, energy e x p e n d i t u r e on f i l -  t r a t i o n w i l l be l e s s and n e t m e t a b o l i c r e q u i r e m e n t s l e s s . The g e n e r a l i n t e r p r e t a t i o n o f t h e r e s u l t s and d i s c u s s i o n o f t h e f e e d i n g a b i l i t i e s o f C a l a n u s plumchrus and C. m a r s h a l l a e i s t h a t G. plumc h r u s has b o t h m e c h a n i c a l and p h y s i o l o g i c a l advantages over C a l a n u s marshallae .  I t appears from- t h e r e g r e s s i o n a n a l y s i s d i s c u s s e d p r e v i o u s l y  t h a t f l u c t u a t i o n s i n C a l a n u s plumchrus and G. m a r s h a l l a e a r e a s s o c i a t e d w i t h y e a r t o y e a r f l u c t u a t i o n s i n t h e deep water t e m p e r a t u r e regime o f the S t r a i t of Georgia e i t h e r d i r e c t l y o r through temperature r e l a t e d f a c tors.  C u r r e n t l y , a t r e n d towards l o w e r deep water t e m p e r a t u r e s has r e s u l -  t e d i n a s h i f t i n f a v o u r o f C a l a n u s m a r s h a l l a e and a d e c l i n e i n C a l a n u s plumchrus.  Over a l o n g p e r i o d o f t i m e , however, i f t h e t e m p e r a t u r e r e -  t u r n s t o more normal l e v e l s t h e e c o l o g i c a l advantages o f G. plumchrus should help t o r e - e s t a b l i s h i t i n i t s t r a d i t i o n a l concentrations i n the Strait.  I f t h e t e m p e r a t u r e remains l o w f o r some t i m e , C. plumchrus  will  be a t a d i s a d v a n t a g e b u t s h o u l d be a b l e t o m a i n t a i n i t s p o p u l a t i o n because of i t s a b i l i t y t o e x p l o i t p o r t i o n s o f t h e f o o d spectrum u n a v a i l a b l e t o C. m a r s h a l l a e . I n c o n d i t i o n s which f a v o u r e d C a l a n u s plumchrus more than u s u a l ( e . g . a b n o r m a l l y warm deep w a t e r ) , G. m a r s h a l l a e would be p u t a t a d i s a d v a n t a g e .  122  I t i s l e s s l i k e l y t h a t C_. m a r s h a l l a e  c o u l d r e c o v e r as w e l l from a d v e r s e  c o n d i t i o n s , as i t i s l e s s c a p a b l e than C_. plumchrus a t e x p l o i t i n g  the  f o o d r e s o u r c e s of i t s environment, p a r t i c u l a r l y i f c o m p e t i t i o n f o r f o o d d e v e l o p s between C. plumchrus and C_. m a r s h a l l a e . countered  i n r e a r i n g C. m a r s h a l l a e  The d i f f i c u l t i e s  i n t h e l a b o r a t o r y may  en-  be i n d i c a t i v e o f  a l o w e r t o l e r a n c e t h a n G_. plumchrus t o some unknown w a t e r q u a l i t y parameter.  T h i s apparently lower t o l e r a n c e supports the hypothesis t h a t  marshallae  G.  i s l e s s a b l e t o "cope w i t h " a d v e r s e c o n d i t i o n s , but does n o t  i n d i c a t e what .the a d v e r s e c o n d i t i o n s might be. The  above arguments suggest t h a t , under more "normal" c o n d i t i o n s ,  Galanus plumchrus c o u l d p e r m a n e n t l y r e p l a c e Galanus m a r s h a l l a e . a r e p l a c e m e n t has not o c c u r r e d i n t h e p a s t , e n v i r o n m e n t a l v o u r i n g G. m a r s h a l l a e p r o b a b l y  such  conditions f a -  occur at s u f f i c i e n t i n t e r v a l s to maintain  the s p e c i e s i n the S t r a i t of Georgia.  O c c a s i o n a l i n t r u s i o n s of c o l d e r  water than u s u a l wouEid p r o b a b l y have t h i s r e s u l t . t i o n s i n t h e two  As  The  current f l u c t u a -  s p e c i e s might t h e n be t h e r e s u l t o f a more i n t e n s e , more  r e g u l a r c o l d water i n t r u s i o n over a p e r i o d o f some y e a r s , as d i s c u s s e d above. The  growth r a t e s o b t a i n e d f o r Galanus plumchrus i n t h e l a b o r a t o r y  agree w e l l w i t h o t h e r p u b l i s h e d r a t e s d e s p i t e low o v e r a l l s u r v i v a l r a t e s . They a r e p r o b a b l y r e p r e s e n t a t i v e of t h e p a t t e r n o f growth i n t h e f i e l d . F u l t o n (1973) o b t a i n e d growth r a t e s f o r G a l a n u s plumchrus of 10.6%AW/day from egg t o GV, Parsons,  but does not d i s c u s s s p e c i f i c r a t e s f r o m s t a g e t o  LeBrasseur  n a u p l i i t o GV  stage.  e t a l . (I969) d e r i v e an o v e r a l l growth r a t e f r o m  o f 6.6%/day, w i t h v a l u e s f r o m 3-5  ments o f t h e l i f e c y c l e .  t o 14% f o r d i f f e r e n t  T h e i r h i g h e s t v a l u e was  o b t a i n e d f o r growth  seg-  123  between t h e n a u p l i a r s t a g e s (an average v a l u e ) and t h e G I . Growth from GI t o G U I was reduced (3-5%/day), b u t p i c k e d up a g a i n between t h e G U I and CV; (8.7%/day).  These v a l u e s suggest t h a t t h e g r e a t e s t growth  occurs  t h r o u g h t h e n a u p l i i and C I , w h i l e my f i g u r e s suggest t h a t maximum growth r a t e occurs through t h e intermediate stages ( C I I t o CIV).  Parsons' data  were t a k e n on c r u i s e s s e p a r a t e d by two week p e r i o d s , and h i s e s t i m a t e s for  t h e t i m e o f f i r s t appearance o f each s t a g e a r e c o n s e q u e n t l y o n l y a c -  c u r a t e w i t h i n s e v e r a l days.  The e r r o r i n t r o d u c e d by t h e s e i n a c c u r a c i e s  would be g r e a t e s t f o r t h e s h o r t term e v e n t s c h a r a c t e r i z i n g r a p i d  growth.  The a v e r a g i n g o f d a t a f o r t h e n a u p l i a r s t a g e s w i l l a l s o l e a d t o d i f f e r ences i n t h e growth r a t e e s t i m a t e s f o r e a r l y s t a g e s .  These f a c t o r s , p l u s  t h e minor d i f f e r e n c e s i n t h e wet weight e s t i m a t e s f o r t h e i n d i v i d u a l stages,, can account f o r most o f t h e d i f f e r e n c e s between P a r s o n s '  growth  r a t e e s t i m a t e s and my own. Because o f t h e f r e q u e n c y w i t h which I was a b l e t o sample g r o w i n g c u l t u r e s o f C. plumchrus,  my estimates- o f growth r a t e p r o b a b l y b e t t e r  r e f l e c t t h e a c t u a l p a t t e r n o f growth t h a n o t h e r p u b l i s h e d r a t e s .  The p  p a t t e r n suggested i s one o f v e r y r a p i d growth t h r o u g h t h e i n t e r m e d i a t e copepodite stages.  T h i s p a t t e r n can a l s o be seen i n t h e f i e l d ,  where  many d i f f e r e n t c o p e p o d i t e s t a g e s can appear w i t h i n a s h o r t t i m e p e r i o d . T h i s r a p i d growth e n a b l e s C a l a n u s plumchrus t o b e t t e r e x p l o i t t h e a v a i l a ble  p h y t o p l a n k t o n , and may be a n o t h e r example o f i t s f i t n e s s t o s u r v i v e  i n the S t r a i t of Georgia. If,  i n s p i t e o f i t s apparent advantages,  C a l a n u s plumchrus i s unable  t o m a i n t a i n h i g h p o p u l a t i o n numbers i n t h e S t r a i t o f G e o r g i a and i s r e p l a c e d by C. m a r s h a l l a e , t h e e c o l o g i c a l i m p l i c a t i o n s a r e c o n s i d e r a b l e .  124  P r e d a t o r s on Galanus plumchrus would need t o e x p l o i t a l t e r n a t i v e of f o o d more h e a v i l y . on G_. m a r s h a l l a e .  sources  T h i s would most l i k e l y meanviincreased p r e d a t i o n  The d i f f e r e n c e i n energy c o n t e n t and s i z e o f t h e  two  s p e c i e s i s such t h a t a p r e d a t o r would have t o remove more than t w i c e t h e number of G. m a r s h a l l a e t o o b t a i n an e q u i v a l e n t r a t i o n .  The i n c r e a s e i n  s e a r c h i n g t i m e which t h i s i m p l i e s would be d e t r i m e n t a l t o t h e p r e d a t o r .  125  SUMMARY Between 1969 and 1974, t h e c o m p o s i t i o n o f t h e S t r a i t o f G e o r g i a z o o p l a n k t o n community s h i f t e d s u b t l y i n r e s p o n s e t o changes i n t h e char a c t e r i s t i c s o f t h e environment.  By u s i n g a s e r i e s o f m u l t i v a r i a t e  a n a l y t i c a l t e c h n i q u e s t o examine z o o p l a n k t o n i c and h y d r o g r a p h i c d a t a , i t i t shown t h a t t h e change i n t h e z o o p l a n k t o n i s t e m p o r a l l y d i r e c t e d w i t h i n t h e p e r i o d o f t h e s t u d y , r a t h e r t h a n f l u c t u a t i n g about an e q u i librium condition.  Changes i n t h e z o o p l a n k t o n can b  t e m p o r a l changes i n the. h y d r o g r a p h i c  e  linked to similar  regime.  C l u s t e r a n a l y s i s groups deep a n d e i n t e r m e d i a t e water i n a rough temp o r a l sequence on t h e b a s i s o f b i o l o g i c a l d a t a .  P r i n c i p a l components and  f a c t o r a n a l y s e s d e s c r i b e a p o s s i b l e p h y s i c a l b a s i s f o r t h e observed temp o r a l d i f f e r e n c e s i n t h e hydrography. s i c a l environment  A l t h o u g h t h e changes i n t h e phy-  a r e c h a r a c t e r i z e d by changes i n temperature and s a l i n -  i t y , t h e y r e f l e c t changes i n o t h e r , unmeasured, parameters a more d i r e c t i n f l u e n c e on t h e z o o p l a n k t o n .  t h a t have had  C a n o n i c a l c o r r e l a t i o n and  r e g r e s s i o n i n d i c a t e t h e importance o f t h e h y d r o g r a p h i c regime t o t h e z o o p l a n k t o n community, w h i l e p r i n c i p a l components a n a l y s i s o f t h e zoop l a n k t o n i n d i c a t e s t h a t 15% w i t h a temporal s h i f t .  of the zooplankton v a r i a n c e i s a s s o c i a t e d  Taken t o g e t h e r , t h e s e a n a l y s e s i n d i c a t e t h a t  t h e changes which have o c c u r r e d i n t h e p h y s i c a l and b i o l o g i c a l s e c t o r s o f t h e environment  a r e r e l a t e d , and f u r t h e r i n d i c a t e t h e p r e s e n c e o f a  s u b t l e t e m p o r a l t r e n d i n t h e z o o p l a n k t o n community o f t h e S t r a i t o f Georgia. A l t h o u g h 15%  o f t h e z o o p l a n k t o n v a r i a n c e i s a s s o c i a t e d w i t h a tem-  p o r a l t r e n d , t h e z o o p l a n k t o n community i s b a s i c a l l y s t a b l e and has a  126  s t r u c t u r e based on t h e v e r t i c a l d i s t r i b u t i o n o f i t s component s p e c i e s . The most o b v i o u s u n i t w i t h i n t h e community i s a group o f deep water species.  Other s p e c i e s g r o u p i n g s a l s o t e n d t o be a s s o c i a t e d w i t h de-  f i n a b l e p a t t e r n s of v e r t i c a l d i s t r i b u t i o n .  A l l o f t h e groups, however,  i n t e r g r a d e s u f f i c i e n t l y t h a t t h e y can n o t r e a d i l y be s u b d i v i d e d i n t o independent  communities.  There i s c o n s i d e r a b l e redundancy i n t h e z o o p l a n k t o n d a t a which can be reduced by c a r e f u l s e l e c t i o n o f s p e c i e s f o r complete m o n i t o r i n g . tor  Fac-  a n a l y s i s p r o v i d e s an o b j e c t i v e means o f s e l e c t i n g key s p e c i e s f o r  continued monitoring.  Seven s p e c i e s ( C a l a n u s plumchrus,  Pseudocalanus  minutus, A c a r t i a l o n g i r e m u s , S a g i t t a e l e g a n s , E u p h a u s i a p a c i f i c a , c i n a sp. and P i t h o n a s p i n i r o s t r i s ) a r e recommended f o r d e t a i l e d t i o n i n t h e S t r a i t of G e o r g i a .  Lima-  observa-  These s p e c i e s a c c u r a t e l y r e p r e s e n t t h e  g e n e r a l z o o p l a n k t o n community and can be r e a d i l y m o n i t o r e d on a l o n g term basis. The o v e r w i n t e r i n g s i z e o f t h e z o o p l a n k t o n community i n t h e S t r a i t of  Georgia i s s t r o n g l y l i n k e d with hydrographic events i n the f a l l .  Changes i n t h e c o m p o s i t i o n o f incoming o c e a n i c water, i n t h e c o m p o s i t i o n of  o u t f l o w i n g f r e s h e r water and i n t h e mechanics o f m i x i n g between t h e s e  two t y p e s o f water a l l a c t t o a l t e r t h e c o m p o s i t i o n o f t h e deep water which i n t r u d e s i n t o t h e S t r a i t o f G e o r g i a i n l a t e summer and f a l l .  These  v a r i a t i o n s i n deep water have i m p o r t a n t e f f e c t s on t h e o v e r w i n t e r i n g popul a t i o n s i z e s o f deep water s p e c i e s , and c o n s e q u e n t l y on t h e makeup o f t h e z o o p l a n k t o n community t h a t i s p r e s e n t i n t h e S t r a i t o f G e o r g i a when t h e s p r i n g z o o p l a n k t o n bloom commences.  H y d r o g r a p h i c e v e n t s i n s p r i n g and  f a l l l a l s o d i r e c t l y a f f e c t t h e a v a i l a b i l i t y o f f o o d by r e g u l a t i n g ,_>hyto  12?  p h y t o p l a n k t o n growth.  Hence t h e y i n d i r e c t l y a f f e c t z o o p l a n k t o n  growth  i n a d d i t i o n t o t h e d i r e c t i n f l u e n c e d e s c r i b e d above. I t i s t h i s f l u c t u a t i o n i n deep water p r o p e r t i e s t h a t has g e n e r a t e d much o f t h e s h i f t i n t h e z o o p l a n k t o n community. of  The most i m p o r t a n t a s p e c t  t h i s r e l a t i o n s h i p i s t h e e f f e c t o f t h e e n v i r o n m e n t a l changes observed  i n deep water temperature s t r u c t u r e on t h e o v e r w i n t e r i n g p o p u l a t i o n s o f Galanus plumchrus and Galanus m a r s h a l l a e .  F l u c t u a t i o n s i n t h e numbers o f  ifehese s p e c i e s a r e p a r t i c u l a r l y c r i t i c a l because o f t h e economic of  Calanus plumchrus.  importance  The t r e n d o f t h e observed changes has been  towards  d e c r e a s e d o v e r w i n t e r i n g numbers o f C a l a n u s plumchrus and i n c r e a s e d numb e r s o f C. m a r s h a l l a e •  Other d a t a suggest t h a t t h e s e changes a r e abnor-  mal and may r e p r e s e n t a permanent s h i f t ; however, t h e r e a r e n o t s u f f i c i e n t d a t a t o c o n f i r m o r deny t h i s p o s s i b i l i t y . The two s p e c i e s o f Calanus a r e s u f f i c i e n t l y s i m i l a r i n d i s t r i b u t i o n and l i f e h i s t o r y t h a t an i n v e s t i g a t i o n o f t h e r e l a t i o n s h i p s between them i s b o t h e c o l o g i c a l l y i n t e r e s t i n g and n e c e s s a r y t o f u r t h e r d e f i n e t h e c h a r a c t e r o f t h e f l u c t u a t i o n s observed i n t h e i r numbers.  Ecological  s e p a r a t i o n o f t h e s p e c i e s i s based l a r g e l y on t h e a b i l i t y o f C a l a n u s plumchrus t o f e e d on p a r t i c l e s down t o about 2.5 ym i n d i a m e t e r , w h i l e C. m a r s h a l l a e can f e e d .only p o o r l y on p a r t i c l e s below about 8.0 ym. In  t h e S t r a i t of Georgia, the concentration of a v a i l a b l e food p a r t i -  c l e s w i t h d i a m e t e r s between 2.0 and 8.0 ym i s c o n s i d e r a b l e . T h i s g i v e s plumchrus an e c o l o g i c a l advantage over C. m a r s h a l l a e which has been a t l e a s t t e m p o r a r i l y o f f s e t by h y d r o g r a p h i c changes i n f a v o u r o f G. m a r s h a l lae.  The advantage i s f u r t h e r enhanced by t h e p a t t e r n o f growth i n C_.  plumchrus.  The e a r l y l i f e h i s t o r y s t a g e s d e v e l o p s l o w l y , and may be  128  able t o adjust t o v a r i a t i o n s i n the t i m i n g of the spring phytoplankton bloom.  I n t e r m e d i a t e s t a g e s a r e c h a r a c t e r i z e d by f a s t growth which may  a l l o w more e f f i c i e n t u t i l i z a t i o n o f t h e p h y t o p l a n k t o n when t h e y a r e a available. I t i s l i k e l y t h a t t h e two s p e c i e s w i l l r e t u r n t o t h e i r h i s t o r i c a l c o n c e n t r a t i o n s i f t h e 'hydrographic regime r e t u r n s t o i t s pre-1969 composition.  T h i s may a l s o b e - t r u e o f t h e g e n e r a l z o o p l a n k t o n community,  but w i l l o n l y pe p r o v a b l e by c o n t i n u e d m o n i t o r i n g o f b o t h t h e z o o p l a n k t o n and hydrography  of the S t r a i t of Georgia.  I f no f u r t h e r change  o c c u r s , t h e p l a n k t i v o r e p o p u l a t i o n o f t h e S t r a i t o f G e o r g i a may s u f f e r . C a l a n u s m a r s h a l l a e i s a l e s s a t t r a c t i v e f o o d s o u r c e due t o i t s s m a l l e r body w e i g h t .  S h i f t i n g t o C. m a r s h a l l a e from C. plumchrus as a f o o d  s o u r c e might be d e t r i m e n t a l t o e c o n o m i c a l l y i m p o r t a n t f i s h s p e c i e s .  129  REFERENCES Ackman, R.C., C.A. E a t o n , J.C. S i p o s , S.N. Hooper and J.D. C a s t e l l . 1970. L i p i d s and f a t t y a c i d s o f two s p e c i e s o f N o r t h A t l a n t i c k r i l l (Megan y c t i p h a n e s n o r v e g i c a and Thysanoessa i n e r m i s ) and t h e i r r o l e i n t h e a q u a t i c f o o d web. J.Fish.Res.Bd.Can. 27:513-533 A l l e n , T.F. 1968. The a l g a e o f r o c k s u r f a c e s i n Grunynedd. Ph.D. T h e s i s , U n i v e r s i t y o f Wales. O r i g i n a l n o t seen, c i t e d by B e a l s (1973) Anderson, G.C. 1965- F r a c t i o n a t i o n o f p h y t o p l a n k t o n communities o f f t h e Washington and Oregon c o a s t s . Limnol.Oceanogr. 10:4-77-480 Anderson, T.W. 1963- The use o f f a c t o r a n a l y s i s i n t h e s t a t i s t i c a l s i s o f m u l t i p l e t i m e s e r i e s . P s y c h o m e t r i k a 28:1-25  analy-  A n g e l , M.V. and M.J.R. Fasham. 1973. SOND C r u i s e , 1965: f a c t o r and c l u s t e r a n a l y s i s o f t h e p l a n k t o n r e s u l t s , a g e n e r a l summary. J . m a r . b i o l . Assoc.U.K. 53:185-231 . 1974. SOND C r u i s e I965: f u r t h e r f a c t o r a n a l y s i s o f t h e t o n d a t a . J.mar.biol.Assoc.U.K. 54:879-894  plank-  _. 1975- A n a l y s i s o f t h e v e r t i c a l and g e o g r a p h i c d i s t r i b u t i o n s of t h e abundant s p e c i e s o f p l a n k t o n i c o s t r a c o d s i n t h e n o r t h - e a s t A t l a n t i c . J . m a r . b i o l . A s s o c . U . K . 55:709-737 Anraku, M. and M. Omori. 1963- P r e l i m i n a r y s u r v e y o f t h e r e l a t i o n s h i p between . t h e i f e g d i n g i h a b i t and t h e s t r u c t u r e o f t h e mouth p a r t s o f 5 marine copepods. Limnol.Oceanogr. 8:116-126 Aron, W i l l i a m . I962. The d i s t r i b u t i o n o f a n i m a l s i n t h e e a s t e r n n o r t h P a c i f i c and t h e i r r e l a t i o n s h i p t o t h e w a t e r masses. L i m n o l . Oceanogr. 4:1-28 A s h t o n , P.S. 1964. E c o l o g i c a l s t u d i e s i n t h e mixed d i p t e r o c a r p f o r e s t o f B r u n e i S t a t e . Oxf.For.Mem. 25. O r i g i n a l n o t seen, c i t e d by G r e i g S m i t h (1971) A u s t i n , M.P. and P. G r i e g - S m i t h . I968. The a p p l i c a t i o n o f q u a n t i t a t i v e methods t o v e g e t a t i o n s u r v e y . I I I . Some m e t h o d o l o g i c a l problems o f d a t a f r o m r a i n f o r e s t . J . E c o l . 56:827-844 B a i n b r i d g e , V. and D.G.T. F o r s y t h . 1972. An e c o l o g i c a l s u r v e y o f a S c o t t i s h h e r r i n g f i s h e r y . P a r t IV. The p l a n k t o n o f t h e n o r t h - w e s t e r n N o r t h S e a i n r e l a t i o n t o t h e p h y s i c a l environment.and t h e d i s t r i b u t i o n o f h e r r i n g . B u l l . M a r . E c o l . 8:21-52 B a r n e s , C.A., A.C. Duxbury and B e t t y - A n n Morse. 1972. C i r c u l a t i o n and s e l e c t e d p r o p e r t i e s o f t h e G o l u m b i a a R i v e r e f f l u e n t a t sea. Chpt. 3 i n A.T. P r u t e r and D.L. A l v e r s o n , eds. The C o l u m b i a R i v e r E s t u a r y , and a d j a c e n t ocean w a t e r s . U n i v e r s i t y o f Washington P r e s s , S e a t t l e and Washington. 868pp  13P  B a r n e s , H. 194-9. A s t a t i s t i c a l s t u d y o f t h e v a r i a t i o n i n v e r t i c a l zooplankton hauls, with s p e c i a l reference t o the l o s s of catch with d i v i d e d h a u l s . J.mar.biol.Assoc.U.K. 28:429-446 . 1952. On t h e use o f t r a n s f o r m a t i o n s i n m a r i n e b i o l o g i c a l s t a t i s t i c s . J . C o n s . C o n s . i n t . E x p l o r . M e r 18:61-71 and S.M. M a r s h a l l . 1951- On t h e v a r i a b i l i t y o f r e p l i c a t e p l a n k t o n samples and some a p p l i c a t i o n s o f " c o n t a g i o u s " s e r i e s t o t h e s t a t i s t i c a l d i s t r i b u t i o n o f c a t c h e s over r e s t r i c t e d p e r i o d s . J . m a r . b i o l . Assoc.U.K. 30:233-263 B a r y , B.M. 1959- S p e c i e s o f z o o p l a n k t o n a s a means o f i d e n t i f y i n g d i f f e r e n t s u r f a c e w a t e r s and d e m o n s t r a t i n g t h e i r movements and m i x i n g . P a c .  S c i . 13:14-34  . 1963a. Temperature, s a l i n i t y and p l a n k t o n i n t h e e a s t e r n N o r t h A t l a n t i c and c o a s t a l w a t e r s o f B r i t a i n , 1957- I- The c h a r a c t e r i z a t i o n and d i s t r i b u t i o n o f s u r f a c e w a t e r s . J.Fish.Res.Bd.Can. 20:789-826 . 1963b. Temperature, s a l i n i t y and p l a n k t o n i n t h e e a s t e r n N o r t h A t l a n t i c and c o a s t a l w a t e r s o f B r i t a i n , 1 9 5 7 . T h I I r e T h e i R e l a t i o n s h i p s between s p e c i e s and water b o d i e s . J .Fish.Res.Bd.Can. 20:1031-1065 . 1963c. Temperature, s a l i n i t y and p l a n k t o n i n t h e e a s t e r n N o r t h A t l a n t i c and c o a s t a l w a t e r s o f B r i t a i n , 1957- III. The d i s t r i b u t i o n of z o o p l a n k t o n i n r e l a t i o n t o water b o d i e s . J.Fish.Res.Bd.Can.  20:1519-1548  . 1964. Temperature, s a l i n i t y and p l a n k t o n i n t h e e a s t e r n N o r t h A t l a n t i c and c o a s t a l w a t e r s o f B r i t a i n , 1957- I V . The s p e c i e s ' r e l a t i o n s h i p t o t h e water body; i t s r o l e i n d i s t r i b u t i o n and i n l s e l e c ^ i n g and u s i n g i n d i c a t o r s p e c i e s . J.Fish.Res.Bd.Can. 21:183-201 B e a l s , E.W. 1973- O r d i n a t i o n : m a t h e m a t i c a l e l e g a n c e and e c o l o g i c a l n a i v e t e . J . E c o l . 61:23-35 B i e r i , R o b e r t . 1959- The d i s t r i b u t i o n o f t h e p l a n k t o n i c chaetognaths i n the P a c i f i c and t h e i r r e l a t i o n s h i p t o t h e water masses. L i m n o l . Oceanogr. 4:1-28 Borgmann, Uwe. 1973 - A n a l y s i s o f copepod h e a r t r a t e s u s i n g A r r h e n i u s plots. C a n . J . Z o o l . 51:893-896 a  . 1973b. T h e o r e t i c a l e q u a t i o n s f o r d e s c r i b i n g s t e a d y s t a t e b i o l o g i c a l r a t e s and t h e i r a p p l i c a t i o n i n a n a l y s i n g p h y s i o l o g i c a l d i f f e r e n c e s among a n i m a l s . M.Sc. T h e s i s , Department o f Z o o l o g y and I n s t i t u t e o f Oceanography, U n i v e r s i t y o f B r i t i s h Columbia. 44pp Bowman, T.E. and J.C. M c L a i n . 1967- V a r i a t i o n and d i s t r i b u t i o n ;of t h e pel a g i c amphipod C y p h o c a r i s c h a l l e n g e r i i n t h e n o r t h - e a s t P a c i f i c ( G a m m a r i d e a : L y s i a n a s s i d a e ) . Proc.U.S.Nat.Mus. 122:1-14  131  Boyd, C a r l . 1976. S e l e c t i o n o f p a r t i c l e s i z e s "by f i l t e r - f e e d i n g A p l e a f o r r e a s o n . Limnol.Oceanogr. 21:175-179  copepods:  B r o d s k y , K.A. 1962. An a t t e m p t a t a b i o m e t r i c a n a l y s i s o f m o r p h o l o g i c a l v a r i a t i o n i n C a l a n u s p a c i f i c u s B r o d s k y (COPEPODA). D o k l . B i o l . S c i . 142:228-230 . 1967. C a l a n o i d a o f t h e f a r e a s t e r n seas and p o l a r b a s i n o f t h e U.S.S.R. T r a n s l a t e d f r o m t h e R u s s i a n "by t h e I s r a e l Program f o r S c i e n t i f i c T r a n s l a t i o n s , J e r u s a l e m . T r a n s l . No. TT-67-51200, 440pp B r o o k s , J . L . and S . I . Dodson. P r e d a t i o n , body s i z e and c o m p o s i t i o n o f t h e p l a n k t o n . S c i e n c e 150:28-35 Buchanan, R. I966. A s t u d y of t h e s p e c i e s c o m p o s i t i o n and e c o l o g y o f t h e p r o t o p l a n k t o n o f a B r i t i s h Columbia i n l e t . Ph.D. T h e s i s , Department o f Botany, U n i v e r s i t y o f B r i t i s h C o l u m b i a . C a m p b e l l , M.H. 1929a. A p r e l i m i n a r y q u a n t i t a t i v e s t u d y o f t h e z o o p l a n k t o n i n t h e S t r a i t o f G e o r g i a . Trans.Roy.Soc.Can., S e r . 3 , 23:1-28 . 1929b. Some free-swimming copepods o f t h e Vancouver r e g i o n . I . TTrans.Roy.Soc.Can., S e r . 3, 23:303-332  Island  . 1930. Some free-swimming copepods o f t h e Vancouver I s l a n d r e g i o n . I I . Trans.Roy.Soc.Can., S e r . 3 , 24:177-182 . 1933- Galanus t o n s u s B r a d y (= C. plumchrus Marukawa) as an economic f a c t o r i n t h e S t r a i t o f G e o r g i a . P r o c . F i f t h P a n - P a c i f i c Sci.Gong.Can. 3:2003-2008 . 1934. The l i f e h i s t o r y a n d t p o s t - e m b r y o n i c development o f t h e copepods, Galanus t o n s u s Brady and E u c h a e t a j a p o n i c a Marukawa. J . B i o l .Bd.Can. 1:1-65 C a s s i e , R.M. and A.D. M i c h a e l . I 9 6 8 . Fauna and sediments o f an i n t e r t i d a l mud f l a t : a m u l t i v a r i a t e a n a l y s i s . J . e x p . m a r . B i o l . E c o l . 2:19-23 C l a r k e , G.L.  1954.  Elements o f e c o l o g y .  John W i l e y and Sons, N.Y.  C o l e , L.C. 1951 • P o p u l a t i o n c y c l e s and random o s c i l l a t i o n s . Manage. 15:233-252  56O  pp  J . W i l d l .>-'a?i  Gomita, G.W., S . M . M a r s h a l l and A.P. O r r . 1966. On t h e b i o l o g y o f Galanus f i n m a r c h i c u s . X I I I . S e a s o n a l changes i n w e i g h t , c a l o r i f i c v a l u e , and o r g a n i c m a t t e r . J . m a r . b i o l . A s s o c . U . K . 46:1-17 Comita, G.W. and D.W. S c h i n d l e r . 1963S c i e n c e 140:1394-1396  C a l o r i f i c values of microcrustacea.  C o n n e l l , J.H. 1 9 6 l a . The i n f l u e n c e o f i n t e r s p e c i f i c c o m p e t i t i o n and o t h e r f a c t o r s on t h e d i s t r i b u t i o n o f t h e b a r n a c l e Chthalamus s t e l l a t u s . E c o l o g y 42:710-723  132  C o n n e l l , J.H. 1 9 6 l b . E f f e c t s o f c o m p e t i t i o n , p r e d a t i o n by T h a i s l a p i l l u s , and o t h e r f a c t o r s on n a t u r a l p o p u l a t i o n s o f t h e b a r n a c l e B a l a n u s b a l a n o i d e s . Ecol.Monogr. 31:61-104 Conover, R . J . 1959• R e g i o n a l and s e a s o n a l v a r i a t i o n i n t h e r e s p i r a t o r y r a t e o f marine copepods. Limnol.Oceanogr. 4:259-268 . 1966a. A s s i m i l a t i o n o f o r g a n i c m a t t e r by z o o p l a n k t o n . Oceanogr. 11:338-345  Limnol.  j_ 1966b. F a c t o r s a f f e c t i n g t h e a s s i m i l a t i o n o f o r g a n i c m a t t e r by z o o p l a n k t o n and t h e q u e s t i o n o f s u p e r f l u o u s f e e d i n g . L i m n o l . Oceanogr. 11:346-354 Corner, E.D.S., C.B. Cowey and S.M. M a r s h a l l . I967. On t h e n u t r i t i o n and metabolism o f z o o p l a n k t o n . V. F e e d i n g e f f i c i e n c y o f C a l a n u s f i n m a r c h i c u s . J.mar.biol.Assoc.U.K. 47:259-270 Corner, E.D.S., R.N. Head, C.C. K i l v i n g t o n and S.M. M a r s h a l l . 1974. On t h e n u t r i t i o n and metabolism o f z o o p l a n k t o n . IX. Studies r e l a t i n g t o t h e n u t r i t i o n o f o v e r w i n t e r i n g Calanus• J.mar.biol.Assoc.U.K. 54:319-331 C o o l e y , W.W. and P.R. Lohnes. 1971- M u l t i v a r i a t e d a t a a n a l y s i s . John W i l e y and Sons, I n c . , N.Y., Lond., Sydney, T o r o n t o . 3~64pp,? Crombie, A.C. 1947. I n t e r s p e c i f i c c o m p e t i t i o n .  J.Anim.Ecol.  16:44-73  C u s h i n g , D.H. I96I. P a t c h i n e s s . Rapp.P-V.Reun.Cons.int.Explor.Mer 153:152 D a l e s , R.P. 1957. P e l a g i c p o l y c h a e t e s o f t h e P a c i f i c Ocean. Inst.Oceanogr. 7:99-168  Bull.Scripps  D a v i s , C.C. 1949. The p e l a g i c Copepoda o f t h e n o r t h e a s t e r n P a c i f i c Ocean. U n i v . W a s h . P u b l . B i o l . 14:1-118 Day,  J.H., J.G. F i e l d and M.P. Montgomery. 1971- The use o f n u m e r i c a l methods t o d e t e r m i n e t h e d i s t r i b u t i o n o f t h e b e n t h i c f a u n a a c r o s s t h e c o n t i n e n t a l s h e l f o f N o r t h C a r o l i n a . J . A n i m . E c o l . 40:93-125  Denman, K.L. and T r e v o r P i a t t . 1975. Coherences i n t h e h o r i z o n t a l d i s t r i b u t i o n s o f p h y t o p l a n k t o n and t e m p e r a t u r e i n t h e upper ocean. Mem. Soc.Roy. d e s S c i . de L i e g e , 6 S e r i e , 7:19-30 e  Dodimead, A . J . , F. F a v o r i t e and T. H i r a n o . 1963. Reviewoof t h e oceanography of t h e S u b a r c t i c P a c i f i c Region. B u l l . No. 13, Int.N.Pac.Fish.Comm. Dodimead, A . J . and G.L. P i c k a r d . I967. A n n u a l changes i n t h e o c e a n i c coast a l waters o f t h e e a s t e r n s u b a r c t i c P a c i f i c . J.Fish.Res.Bd.Can. 24:2207-2227  Doe,  L.A.E. 1955> O f f s h o r e w a t e r s o f t h e Canadian P a c i f i c c o a s t . Res.Bd.Can. 12:1-34  J.Fish.  133  Dunbar, M.J. I960. The e v o l u t i o n o f s t a b i l i t y i n marine environments; n a t u r a l s e l e c t i o n a t t h e l e v e l o f t h e ecosystem.. Am .Nat. 94:129-136 E l t o n , G.S. 1942. V o l e s , mice and lemmings. Problems i n p o p u l a t i o n dynamics . O x f o r d U n i v e r s i t y P r e s s , Lond. 496pp .adi^46.SGo'mpetition9ahd t h e s t r u c t u r e o f e c o l o g i c a l communities. J . A n i m . E c o l . 15:54-68 . and R.S. M i l l e r . 1954. The e c o l o g i c a l s u r v e y o f a n i m a l communit i e s , w i t h a p r a c t i c a l system o f c l a s s i f y i n g h a b i t a t s by s t r u c t u r a l c h a r a c t e r s . J . E c o l . 42:460-496 Evans, M.S. 1973- The d i s t r i b u t i o n a l e c o l o g y o f t h e c a l a n o i d copepod P a r e u c h a e t a e l o n g a t a E s t e r l e y . Ph.D. T h e s i s , I n s t i t u t e o f Oceanography and Department o f Z o o l o g y , U n i v e r s i t y o f B r i t i s h Columbia. 112pp F a g e r , E.W. 1973> E s t i m a t i o n o f m o r t a l i t y c o e f f i c i e n t s from f i e l d of z o o p l a n k t o n . Limnol.Oceanogr. 18:297-300  samples  and J.A. McGowan. 1963- Z o o p l a n k t o n s p e c i e s groups i n t h e N o r t h P a c i f i c . S c i e n c e 140:453-460 Fasham, M.J.R. and M.V. A n g e l . 1975- The r e l a t i o n s h i p o f t h e z o o g e o g r a p h i c d i s t r i b u t i o n s of the planktonic ostracods i n the north-east A t l a n t i c to t h e water masses. J.mar.biol.Assoc.U.K. 55:739-757 F i s h e r , L.R. I962. The t o t a l l i p i d m a t e r i a l i n some s p e c i e s o f marine z o o p l a n k t o n . Rapp.P-V.Reun.Cons.int.Explor.Mer 153:129-136 F r o s t j - B.W. 1974. C a l a n u s m a r s h a l l a e , a new s p e c i e s o f c a l a n o i d copepod c l o s e l y a l l i e d t o t h e s i b l i n g s p e c i e s G. f i n m a r c h i c u s and C. g l a c i a lis. M a r . B i o l . 26:77-99 F u l t o n , John. 1968. A l a b o r a t o r y manual f o r t h e i d e n t i f i c a t i o n o f B r i t i s h Columbia marine z o o p l a n k t o n . Fish.Res.Bd.Can., Tech.Rept. No. 55. 1972. Keys and r e f e r e n c e s t o r t h e e m a r i n e copepods o f B r i t i s h Columbia. Fish.Res.Bd.Can., Tech.Rept. No. 313 . 1973- Some a s p e c t s o f t h e l i f e h i s t o r y o f C a l a n u s plumchrus Marukawa i n t h e S t r a i t o f G e o r g i a . J.Fish.Res.Bd.Can. 30:811-815 Gardner, G.A. 1972. The d i s t r i b u t i o n • o f t h e l i f e h i s t o r y s t a g e s o f Galanus plumchrus Marukawa (Copepoda:Calanoida) i n t h e S t r a i t o f G e o r g i a . M.Sc. T h e s i s , I n s t i t u t e o f Oceanography and Department o f Z o o l o g y , U n i v e r s i t y o f B r i t i s h Columbia. 55+v PP Gauld, D.T. 1964. F e e d i n g i n p l a n k t o n i c copepods. Pages 239-245 i n D.J. C r i s p , ed., G r a z i n g i n t e r r e s t r i a l and marine environments. B l a c k w e l l , Oxford.  134  Geary, R.C. 1936. Moments o f t h e r a t i o o f t h e mean d e v i a t i o n t o t h e s t a n d a r d d e v i a t i o n f o r normal samples. B i o m e t r i k a 28:295-305 G e y n r i k h , A.K. 1968. S e a s o n a l phenomena i n t h e p l a n k t o n o f t h e n o r t h e a s t P a c i f i c Ocean. Oceanology 8:231-239 G i l f i l l a n , E.S. I967. A new method o f d e t e r m i n i n g the e f f i c i e n c y of towed p l a n k t o n samplers. M.Sc. T h e s i s , I n s t i t u t e of Oceanography and Department of Zoology, U n i v e r s i t y o f B r i t i s h Columbia. 186pp G l a s s , G.V. and P.A.  Res. 36:566-587  T a y l o r . 1966. F a c t o r a n a l y s i s methodology.  Rev.Educ.  G o o d a l l , D.W. 1954. O b j e c t i v e methods f o r t h e c l a s s i f i c a t i o n o f v e g e t a t i o n . I I I . An essay i n t h e use o f f a c t o r a n a l y s i s . A u s t . J . B b t . 2:304-324 G r i e g - S m i t h , P. 1971- A p p l i c a t i o n of n u m e r i c a l methods t o t r o p i c a l f o r e s t s . Pages 195-206 i n P a t i l , G.P., E.G. P i e l o u and W.E. Waters, eds., S t a t i s t i c a l e c o l o g y , V3. The P e n n s y l v a n i a S t a t e U n i v e r s i t y P r e s s , U n i v e r s i t y P a r k and London. Hansen, D.E. 1973- A s t u d y o f s u r f a c e , 50 m and 200 m temperature and s a l i n i t y f l u c t u a t i o n s a t ocean weather s t a t i o n November, 1968-1970. M.Sc. T h e s i s , U.S. N a v a l P o s t g r a d u a t e S c h o o l , Monterey, C a l i f . O r i g i n a l n o t seen, a b s t r a c t e d i n Oceanic A b s t r a c t s , 1973H a r d i n , G. i960. The c o m p e t i t i v e e x c l u s i o n p r i n c i p l e .  S c i e n c e 131:1292-1298  H a r g r a v e , B.T. and G.H. Geen. 1970. E f f e c t s o f copepods g r a z i n g on two n a t u r a l p h y t o p l a n k t o n p o p u l a t i o n s (A. t o n s a ) . J.Fish.Res.Bd.Can.  27:1395-1403  H e i n l e , D.R. 1969- C u l t u r e of c a l a n o i d copepods i n s y n t h e t i c sea J.Fish.Res.Bd.Can. 26:150-153  water.  H e i n r i c h , A.K. 1962a. On t h e p r o d u c t i o n o f copepods i n t h e B e r i n g Sea. I n t . R e v . g e s . H y d r o b i o l . 47:465-469 . 1962b. The l i f e h i s t o r i e s o f p l a n k t o n i c a n i m a l s and s e a s o n a l c y c l e s o f p l a n k t o n communities i n t h e oceans. J.Cons.Cons.int.Explor. Mer 27:15-24 H e r l i n v e a u x , R.H. and L.F. Giovando. I969. Some oceanographic f e a t u r e s o f the i n s i d e passage between Vancouver I s l a n d and t h e mainland o f B r i t i s h Columbia. Fish.Res.Bd.Can., Tech. Rept. No. 142 Hoar, W.S. I966. G e n e r a l and comparative p h y s i o l o g y . Englewood C l i f f s , N.J.  Prentice-Hall,  Hodgkin, E.P. and R.J. R i p p i n g a l e . 1971- I n t e r s p e c i e s c o n f l i c t i n d e s t u a r i n e copepods. Limnol.Oceanogr. 16:573-576  135  H o p k i n s , T.L. 19&3- The v a r i a t i o n i n t h e c a t c h o f p l a n k t o n n e t s i n a s y s tem o f e s t u a r i e s . J.Mar.Res. 21:39-47 H o t e l l i n g , H. 1935- The most p r e d i c t a b l e c r i t e r i o n .  J.Ed.Psych. 26:139-142  . 1936- R e l a t i o n s between two s e t s o f v a r i a t e s .  Biometrika  28:3211-377  Hummon, W.D. 1974. S^„: a s i m i l a r i t y i n d e x based on shared s p e c i e s d i v e r s i t y , used t o a s s e s s t e m p o r a l and s p a t i a l r e l a t i o n s among i n t e r t i d a l marine G a s t r o t r i c h a . O e c o l o g i a 17:203-220 H u t c h i n s o n , G.E. I96I. The paradox o f t h e p l a n k t o n .  Am.Nat. 95:137-145  Hughes, R.N., D.L. P e e r and K.H. Mann. 1972. Use o f m u l t i v a r i a t e a n a l y s i s t o i d e n t i f y y f u n c t i o n a l components o f t h e benthos i n S t . M a r g a r e t ' s Bay, Nova S c o t i a . Limnol.Oceanogr. 17:111-121 I k e d a , Tsumotu. 1970. R e l a t i o n s h i p between r e s p i r a t i o n and body s i z e i n marine p l a n k t o n a n i m a l s a s a f u n c t i o n o f t h e t e m p e r a t u r e o f t h e h a b i t a t . B u l l . F a c . F i s h . , Hokkaido U. 21:91-112 I n s t i t u t e o f Oceanography, U n i v e r s i t y o f B r i t i s h Columbia. 1970. D a t a r e p o r t 30: B r i t i s h Columbia I n l e t s and P a c i f i c c r u i s e s , I969 . 1971. D a t a r e p o r t 32: B r i t i s h Columbia i n l e t s and P a c i f i c c r u i s e s , 1970 . 1972. D a t a r e p o r t 33: B r i t i s h Columbia i n l e t s and P a c i f i c c r u i s e s , 1971 . 1973' D a t a r e p o r t 3^: B r i t i s h Columbia i n l e t s and P a c i f i c c r u i s e s , 1972 . 1974. D a t a r e p o r t 35: B r i t i s h Columbia i n l e t s and P a c i f i c c r u i s e s , 1973 . 1975- D a t a r e p o r t 37: B r i t i s h Columbia i n l e t s c r u i s e s , 1974 J e f f r i e s , H.P. I967. S a t u r a t i o n o f e s t u a r i n e z o o p l a n k t o n by c o n g e n e r i c a s s o c i a t e s . Pages 500-508 i n L a u f f , G.H., ed., E s t u a r i e s : e c o l o g y and p o p u l a t i o n s . Amer.Assoc.Adv.Sci., P u b l . No. 83, Washington, D.C. K i n n e , 0tto.(ed.). 1970. I n t e r n a t i o n a l symposium " C u l t i v a t i o n o f marine organisms and i t s importance f o r marine b i o l o g y " , S e p t . 8-12, I969. H e l g o l .Wiss .Meeresunters. 20:1-171 K i t c h e n , J.C., D. Menzies, Hasong P a k and J.R.V. Z a n e v e l d . 1975. P a r t i c l e s i z e d i s t r i b u t i o n s i n a r e g i o n o f c o a s t a l u p w e l l i n g a n a l y s e d by c h a r a c t e r i s t i c v e c t o r s . Limnol.Oceanogr. 20:775-783  136  L e B r a s s e u r , R . J . 1959- S a g i t t a l y r a , a b i o l o g i c a l i n d i c a t o r o f s p e c i e s i n the s u b a r c t i c w a t e r s o f t h e e a s t e r n P a c i f i c Ocean. J.Fish.Res.Bd.Can.  16:795-805  . I969. Growth o f j u v e n i l e chum salmon (Onc'orhynchus k e t a ) under d i f f e r e n t f e e d i n g r e g i m e s . J.Fish.Res.Bd.Can. 26:1631-1645 ,?WdE. B a r r a c l o u g h , O.D. Kennedy and T.R. P a r s o n s . 1969- P r o d u c t i o n s t u d i e s i n t h e S t r a i t o f G e o r g i a . P a r t I I I . O b s e r v a t i o n s on t h e f o o d o f l a r v a l and j u v e n i l e f i s h i n t h e F r a s e r R i v e r Plume, F e b r u a r y to May, 1967. J . e x p . m a r . B i o l . E c o l . 3:51-61 L e B r a s s e u r , R . J . and O.D. Kennedy. 1972. M i c r o z o o p l a n k t o n i n c o a s t a l and o c e a n i c a r e a s o f t h e P a c i f i c S u b a r c t i c Water Mass: a p r e l i m i n a r y r e p o r t . Pages 355~365 i n T a k e n o u t i , A.'Y. ( e d . ) , B i o l o g i c a l oceanography o f t h e n o r t h e r n N o r t h P a c i f i c Ocean. I d e m i t s u Shoten, Tokyo, Japan. 626pp Lee, R.F., J e d H i r o t a and A.M. B a r n e t t . 1971- D i s t r i b u t i o n and i m p o r t a n c e of wax e s t e r s i n marine copepods.and o t h e r z o o p l a n k t o n . Deep-Sea Res. 18:1147-1165 Lee, R.F., J e d H i r o t a , J.G. N e v e n z e l , R i c h a r d Sauerheber, A.A. Benson and A l a n L e w i s . 1972. L i p i d s i n t h e marine environment. Gal.Mar. Res.Comm., GalGOFI Rept. 16:95-102 Lee, R.F., J.G. N e v e n z e l and A.G. L e w i s . 1974. L i p i d changes d u r i n g t h e l i f e c y c l e o f t h e marine copepod, E u c h a e t a j a p o n i c a Marukawa. L i p i d s 9:891-898 Legare, J.E.H. 1957- The q u a l i t a t i v e and q u a n t i t a t i v e d i s t r i b u t i o n o f p l a n k t o n i n t h e S t r a i t o f G e o r g i a i n r e l a t i o n t o c e r t a i n oceanogra:p h i c f a c t o r s . J.Fish.Res.Bd.Can. 14:521-552 Leong, R5J.H. and G.P. O'Gonnell. I969. A l a b o r a t o r y s t u d y o f p a r t i c u l a t e and f i l t e r f e e d i n g o f t h e n o r t h e r n anchovy ( E n g r a u l i s mordax). J.Fish.Res.Bd.Can. 26:557-582 L e w i s , A.G. 1976-. .Monthly . n u t r i e n t and c h l o r o p h y l l v a l u e s f o r Juan de F u c a S t r a i t , June-December, 1973D a t a r e p o r t 40, I n s t i t u t e o f Oceanography, U n i v e r s i t y o f B r i t i s h C o l u m b i a L e w i s , A.G1 and A. Ramnarine. I969. Some c h e m i c a l f a c t o r s a f f e c t i n g t h e e a r l y d e v e l o p m e n t a l s t a g e s o f Euchaeta j a p o n i c a (Crustacea:Copepoda: C a l a n o i d a ) i n t h e l a b o r a t o r y . J.Fish.Res.Bd.Can. 26:1347-1362 L e w i s , A.G., A. Ramnarine and M.S. Evans. 1971- N a t u r a l c h e l a t o r s - an i n d i c a t i o n o f a c t i v i t y w i t h t h e c a l a n o i d copepod E u c h a e t a j a p o n i c a . M a r . B i o l . 11:1-4  137  L e w i s , A.G., P.H. W h i t f i e l d and A. Ramnarine. 1972. Some p a r t i c u l a t e and s o l u b l e a g e n t s a f f e c t i n g t h e r e l a t i o n s h i p between m e t a l t o x i c i t y and organism s u r v i v a l i n t h e c a l a n o i d copepod E u c h a e t a j a p o n i c a . Mar. B i o l . 17:215-221 Lie,  U. and J.G. K e l l e y . 1970. B e n t h i c i n f a u n a communities o f f t h e c o a s t of Washington and i n Puget Sound: i d e n t i f i c a t i o n and d i s t r i b u t i o n o f the communities. J.Fish.Res.Bd.Can. 27:621-651  L i n d s t r o m , S.G. 1974. M a r i n e b e n t h i c a l g a l communities i n t h e F l a t Top I s l a n d s a r e a o f G e o r g i a S t r a i t . M.Sc. T h e s i s , Department o f Botany, U n i v e r s i t y o f B r i t i s h C o l u m b i a . vi+107pp L i n f o r d , E. 1965• B i o c h e m i c a l s t u d i e s on marine z o o p l a n k t o n . I I . V a r i a t i o n s i n t h e l i p i d c o n t e n t o f some M y s i d a c e a . J . C o n s . C o n s . i n t . E x p l o r . M e r 30:16-27 L i t t l e p a g e , J . L . 1964. S e a s o n a l v a r i a t i o n i n t h e l i p i d c o n t e n t o f two A n t a r c t i c marine C r u s t a c e a . A c t u a l . S c i e n t . i n d . , B i o l . A n t a r c . No.  1312  L l o y d , M., J.H. Z a r and J.R. K a r r . I968. On t h e c a l c u l a t i o n o f i n f o r m a t i o n - thebre.ticafkameasures o f d i v e r s i t y ^ Am.Midi .Nat. 79:257-272 Marlowe, C . J . and G.B. M i l l e r . 1975. P a t t e r n s o f v e r t i c a l d i s t r i b u t i o n and m i g r a t i o n o f z o o p l a n k t o n a t Ocean S t a t i o n 'P'. Limnol.Oceanogr. 20:824-844. M a r s h a l l , S.M. 197311:57-120  R e s p i r a t i o n and f e e d i n g i n copepods.  Adv.Mar.Biol.  and A.P. O r r . 1955a. On t h e b i o l o g y o f C a l a n u s f i n m a r c h i c u s . ' V I I I . Food uptake, a s s i m i l a t i o n and e x c r e t i o n i n a d u l t and s t a g e V C a l a n u s . J . m a r . b i o l . A s s o c . U . K . 34:495-529 M a r s h a l l , S.M. and A.P. O r r . 1955b. The b i o l o g y o f a marine copepod, Galanus f i n m a r c h i c u s ( G u n n e r u s ) . O l i v e r and Boyd, E d i n b u r g h . I88pp Marukawa, H. 1921. P l a n k t o n l i s t and some new s p e c i e s o f copepods from the n o r t h e r n w a t e r s o f Japan. B u l l . I n s t . O c e a n o g r . (Monaco), No.  384  M c A l l i s t e r , C D . , T.R. P a r s o n s and J.D.H. S t r i c k l a n d , i960. P r i m a r y p r o d u c t i v i t y a t s t a t i o n 'E' i n t h e n o r t h - e a s t P a c i f i c Ocean. J.Cons. C o n s . i n t . E x p l o r . M e r 25:240-259 McHardy, R.A. I96I. C a l i b r a t i o n o f Clarke-Bumpus p l a n k t o n s a m p l e r s i n t h e field. MssitRepte No. 8, I n s t i t u t e o f Oceanography, U n i v e r s i t y o f B r i t i s h C o l u m b i a . lOpp M i l l s , E.L. 1969. The community concept i n marine z o o l o g y , w i t h comments on c o n t i n u a and i n s t a b i l i t y o f some marine communities: a r e v i e w . 5 J.Fish.Res.Bd.Can. 26:1415-1428  138  Montgomery, R.B. 1955- C h a r a c t e r i s t i c s o f s u r f a c e water a t weather s h i p J . Pages 331-33^ i i i P a p e r s i n M a r i n e B i o l o g y and Oceanography. Pergamon P r e s s , L t d . , N.Y. M o r i , Takamochi. 1964. The p e l a g i c copepoda from t h e n e i g h b o u r i n g of Japan, 2nd ed. The Sayo Co. I n c . , Tokyo. 310pp M u l l i n , M.M. 1963- Some f a c t o r s a f f e c t i n g t h e f e e d i n g o f marine of t h e genus C a l a n u s . Limnol.Oceanogr. 8:239-250  waters copepods  . 1968. The f e e d i n g b e h a v i o u r o f p l a n k t o n i c marine copepods and the s e p a r a t i o n o f t h e i r e c o l o g i c a l n i c h e s . S c r i p p s Inst.Oceanogr. C o n t r i b . 38:1835-1842 N a t i o n a l Academy o f S c i e n c e s . 1969- Recommended p r o c e d u r e s f o r measuring the p r o d u c t i v i t y o f p l a n k t o n s t a n d i n g s t o c k and r e l a t e d o c e a n i c p r o p e r t i e s . B i o l o g i c a l Methods P a n e l , Committee on Oceanography; D i v i s i o n o f E a r t h S c i e n c e s , N a t i o n a l R e s e a r c h C o u n c i l , Wash., D.C. 57PP N e v e n z e l , J.C. 1970. Occurrence, f u n c t i o n and b i o s y n t h e s i s o f wax e s t e r s i n marine organisms. L i p i d s $\308-319 N i v a l , P a u l and S. N i v a l . 1973- E f f i c a c i t e d e f i l t r a t i o n d e s copeppdes p l a n k t o n i q u e s . Ann.Inst.Oceanogr., P a r i s 49:134-144 . 1976. P a r t i c l e r e t e n t i o n a b i l i t i e s o f an h e r b i v o r o u s copepod, A c a r t i a c l a u s i i ( a d u l t and c o p e p o d i t e s t a g e s ) : e f f e c t s on g r a z i n g . Limnol.Oceanogr. 21:24-38 O ' C o n n e l l , C P . 1972. The i n t e r r e l a t i o n o f b i t i n g and f i l t e r i n g i n t h e f e e d i n g a c t i v i t y o f t h e n o r t h e r n anchovy ( E n g r a u l i s mordax). J.Fish.Res.Bd.Can. 29:285-293 Odum, E.P. 1971. Fundamentals o f e c o l o g y , 3rd ed. SSaunders, P h i l a d e l p h i a . and A.E. S m a l l e y . 1959- Comparison o f energy f l o w o f a h e r b i v o r o u s and d e p o s i t f e e d i n g i n v e r t e b r a t e i n a s a l t marsh ecosystem. Proc.Nat.Acad.Sci.U.S.A. 45:617-622 O r l o c i , L a s z l o . 1973- O r d i n a t i o n by resemblance m a t r i c e s . Chpt. 10 i n W h i t t a k e r , R.H. ( e d . ) , O r d i n a t i o n and c l a s s i f i c a t i o n o f communities. Dr. W. Junk b-v, P u b l i s h e r s , The Hague. 737PP Paffenhb'fer, G.A. and J.D.H. S t r i c k l a n d . . I970. A n o t e on t h e f e e d i n g o f C a l a n u s h e l g o l a n d i c u s on d e t r i t u s . M a r . B i o l . 5:97~99 Pandyan, A.S. 1971- Food and t r o p h i c r e l a t i o n s h i p s o f t h e d e v e l o p m e n t a l s t a g e s o f E u c h a e t a j a p o n i c a Marukawa and C a l a n u s plumchrus Marukawa. Ph.D. T h e s i s , I n s t i t u t e o f Oceanography, U n i v e r s i t y of B r i t i s h Columbia. P a q u e t t e , R.G. and H.F. F r o l a n d e r . 1957- Improvements i n t h e Clarke-Bumpus p l a n k t o n s a m p l e r . J . C o n s . C o n s . i n t . E x p l o r . M e r 22:284-288  139  P a r k , T.S. I 9 6 6 . A new s p e c i e s of B r a d y i d i u s (Gopepcda:Galanoida) from t h e P a c i f i c Soast of N o r t h A m e r i c a . J.Fish.Res.Bd.Can. 23:805-811 . I 9 6 7 . Two new s p e c i e s o f copepods from t h e S t r a i t of G e o r g i a , B r i t i s h Columbia, Canada. J.Fish.Res.Bd.Can. 24:231-241 P a r s o n s , T.R. 1972. S i z e f r a c t i o n a t i o n o f p r i m a r y p r o d u c e r s i n t h e suba r c t i c P a c i f i c Ocean. Pages 275-278 i n T a k e n o u t i , A.Y. ( e d . ) , B i o l o g i c a l oceanography of t h e n o r t h e r n N o r t h P a c i f i c Ocean. I d e m i t s u 5 Shoten, Tokyo, Japan. 626pp P a r s o n s , T.R. and R . J . L e B r a s s e u r . 1970. The a v a i l a b i l i t y o f f o o d t o d i f f e r e n t t r o p h i c l e v e l s i n t h e marine f o o d c h a i n . Pages 325-3^3 i n S t e e l e , J.H. ( e d . ) , Marine Food C h a i n s . O l i v e r and Boyd, E d i n b u r g h P a r s o n s , T.R., R.J. L e B r a s s e u r and W.E. B a r r a c l o u g h . 1970. L e v e l s o f p r o d u c t i o n i n t h e p e l a g i c environment of t h e S t r a i t o f G e o r g i a , B r i t i s h Columbia: a r e v i e w . J.Fish.Res.Bd.Can. 27:1251-1264 P a r s o n s , T.R., R.J. L e B r a s s e u r , J.D. F u l t o n and O.D. Kennedy. 1969. P r o d u c t i o n s t u d i e s i n t h e S t r a i t of Georgia.. P a r t I I . Secondary p r o d u c t i o n under t h e F r a s e r R i v e r Plume, F e b r u a r y t o May, 1967J . e x p . m a r . B i o l . E c o l . 3:39~50 P a r s o n s , T.R. and H. S e k i . 1970. Importance and g e n e r a l i m p l i c a t i o n s o f o r g a n i c m a t t e r i n a q u a t i c environments. Pages 1-28 i n Hood, D.W. (ed.), Organic matter i n n a t u r a l waters• I n s t . M a r . S c i . , U n i v e r s i t y of A l a s k a , Occas. P u b l . No. 1. 625pp Parsons, P a r s o n s , T.R., K. Stephens and R.J. L e B r a s s e u r . 1969- P r o d u c t i o n s t u d i e s i n t h e S t r a i t o f G e o r g i a . P a r t I . P r i m a r y p r o d u c t i o n under t h e F r a s e r R i v e r Plume, F e b r u a r y t o May, I 9 6 7 . J . e x p . m a r . B i o l . E c o l . 3:27-38 P a r s o n s , T.R. and Masuyuki T a k a h a s h i . 1973- B i o l o g i c a l p r o c e s s e s . Pergamon P r e s s , N.Y. I86pp  oceanographic  P e t i p a , T.S. 1965- The f o o d s e l e c t i v i t y o f C a l a n u s h e l g o l a n d i c u s . Pages 100-110 i n I n v e s t i g a t i o n o f t h e p l a n k t o n o f t h e B l a c k Sea and t h e Sea o f Azov" Akad.Sci.Ukr.S.S.R. (M.A.F.F. t r a n s l . N.S. 72; o r i g i n a l n o t seen, c i t e d by M a r s h a l l 1973) P i c k a r d , G.L. 1956. S u r f a c e and bottom c u r r e n t s i n t h e S t r a i t o f G e o r g i a . J.Fish.Res.Bd.Can. 13:581-590 . 1975- Annual and l o n g e r term v a r i a t i o n s ©f deepwater p r o p e r t i e s i n t h e c o a s t a l w a t e r s of s o u t h e r n B r i t i s h Columbia. J.Fish.Res.Bd.Can. 32:1561-1587 P i a t t , T r e v o r , V.M. Brown and B. I r w i n . 1969- C a l o r i c and carbon e q u i v a l e n t s o f z o o p l a n k t o n biomass. J.Fish.Res.Bd.Can. 26:2345-2349  140  Ponomareva, L.A .!, 1963 . E u p h a u s i i d s o f t h e N o r t h P a c i f i c . T h e i r d i s t r i b u t i o n and e c o l o g y . Akademiya Nauk S.S.S.R., I n s t i t u t O k e a n o l o g y i i . T r a n s l a t e d from t h e R u s s i a n by t h e I s r a e l Program f o r S c i e n t i f i c T r a n s l a t i o n s , J e r u s a l e m , 1966. 1  P o u l e t , S.A. 1976. F e e d i n g o f P s e u d o c a l a n u s minutus on l i v i n g and nonl i v i n g p a r t i c l e s . M a r . B i o l . 34:117-125 Raymont, J.E.G. • P l a n k t o n and p r o d u c t i v i t y i n t h e oceans. P r e s s L t d . , Lond., N.Y., T o r o n t o . 660pp  Pergamon  Regan, Lance. 1963- F i e l d t r i a l s w i t h t h e Clarke-Bumpus p l a n k t o n sampler. Ms. Rept. No. 16, I n s t i t u t e o f Oceanography, U n i v e r s i t y o f B r i t i s h Columbia. Richman, S. and J.N. Rogers. 1969- F e e d i n g o f C a l a n u s h e l g o l a n d i c u s on s y n c h r o n o u s l y growing p o p u l a t i o n s o f t h e marine d i a t o m D i t y l u m b r i g h t w e l l i i . Limnol.Oceanogr. 14:701-709 R i l e y , G.A. 1970. P a r t i c u l a t e o r g a n i c m a t t e r i n seawater. 8:1-118  Adv.Mar.Biol.  R o h l f , F . J . and R.R. S o k a l . 1962. The d e s c r i p t i o n o f taxonomic r e l a t i o n s h i p s by f a c t o r a n a l y s i s . S y s t . Z o o l . 11:1-16 R u s s e l l , F.S. 1935• On t h e v a l u e o f c e r t a i n p l a n k t o n i c a n i m a l s a s i n d i c a t o r s o f water movements i n t h e E n g l i s h Channel and N o r t h Sea. J.mar. b i o l . A s s o c . U . K . 29:309-332 . 1936a. A r e v i e w o f some a s p e c t s o f p l a n k t o n r e s e a r c h . P-V.Reun.Cons.int.Explor.Mer 95:3-31  Rapp.  .19'1936b. O b s e r v a t i o n s on t h e d i s t r i b u t i o n o f p l a n k t o n a n i m a l i n d i c a t o r s made on C o l . E.T. P e e l j s y a c h t " S t . George!! i n t h e mouth of t h e E n g l i s h C h a n n e l . J.mar.biol.Assoc.U.K. 20:507-552 . 1939- H y d r o g r a p h i c a l and b i o l o g i c a l c o n d i t i o n s i n t h e N o r t h S e a as i n d i c a t e d by p l a n k t o n organisms. J . C o n s . C o n s . i n t . E x p l o r . M e r 14:171-  192  S a i l a , S.G. and J.D. P a r r i s h . 1972. E x p l o i t a t i o n e f f e c t s upon i n t e r s p e c i f i c r e l a t i o n s h i p s i n marine ecosystems. F i s h . B u l l . 70:383-393 S e a r s , Mary and G.L. C l a r k e . 1940. Annual f l u c t u a t i o n s i n t h e abundance of marine z o o p l a n k t o n . B i o l . B u l l . 79:321-328 S e k i , H. and O.D. Kennedy. I969. M a r i n e b a c t e r i a and o t h e r h e t e r o t r o p h s as f o o d f o r z o o p l a n k t o n i n t h e S t r a i t o f G e o r g i a d u r i n g t h e w i n t e r . J.Fish.Res.Bd.Can. 26:3165-3173 S e k i , H., K.V. Stephens and T.R. P a r s o n s . I969• The c o n t r i b u t i o n o f a l l o c h thonous b a c t e r i a and o r g a n i c m a t e r i a l s f r o m a s m a l l r i v e r i n t o a s e m i - e n c l o s e d a r e a . A r c h . H y d r o b i o l . 66:37-^7  141  S l o b o d k i n , L.B. 1954. P o p u l a t i o n dynamics i n Daphnia o b t u s a Kunz. Ecol.Monogr. 24:69-88 Snedecor, G.W. and W.G. Cochran. 196?. S t a t i s t i c a l methods. S t a t e U n i v e r s i t y P r e s s , Ames, Iowa. 593PP  The Iowa S t  S o k a l , R.R. and G.D. M i c h e n e r . 1958. A s t a t i s t i c a l method f o r e v a l u a t i n g s y s t e m a t i c r e l a t i o n s h i p s . U . K a n . S c i . B u l l . 38:1409=1438 S o k a l , R.R. and P.H.A. S n e a t h . 1963- P r i n c i p l e s o f n u m e r i c a l taxonomy. W.H. Freeman and Co., San F r a n c i s c o and Lond. 359PP Steedman, H.F. 1976. G e n e r a l and a p p l i e d d a t a on formaldehyde f i x a t i o n and p r e s e r v a t i o n o f marine z o o p l a n k t o n . Pages 103-154 i n Steedman, H.F. ( e d . ) , Z o o p l a n k t o n f i x a t i o n and p r e s e r v a t i o n , . Monographs on o c e a n o g r a p h i c methodology 4, t h e UNESCO P r e s s , P a r i s . 350pp Stephens, K., J . D . F F u l t o n and O.D. Kennedy. I969. Summary o f b i o l o g i c a l oceanographic o b s e r v a t i o n s i n t h e S t r a i t o f G e o r g i a , I965-I968. Fish.Res.Bd.Can., Tech. Rept. No. 110 S t e w a r t , D.K. and W.A. Love. I968. A g e n e r a l c a n o n i c a l c o r r e l a t i o n i n d e x . P s y c h o l . B u l l . 70:160-163 S v e r d r u p , H.U. and R.H. F l e m i n g . 1941. The waters o f f t h e c o a s t o f s o u t h e r n C a l i f o r n i a , March t o J u l y , 1937. B u l l . S c r i p p s I n s t . O c e a n o g r . 4:261-378 S v e r d r u p , H.U., M.W. Johnson and R.H. F l e m i n g . 1942. The oceans. H a l l , I n c . , Englewood C l i f f s , N.J. 1087pp T a i t , R.V. I968. Elements o f marine e c o l o g y .  B u t t e r w o r t h s , Lond.  Prentice272pp  T e b b l e , N. 1962. The d i s t r i b u t i o n o f p e l a g i c p o l y c h a e t e s a c r o s s t h e N o r t h P a c i f i c Ocean. ;B.uIl'.Brit ;Mus. (Nat . H i s t . )ZSo<hlog-j'373-492 Thorson, Gunnar. 1966. Some f a c t o r s i n f l u e n c i n g t h e r e c r u i t m e n t and e s t a b l i s h m e n t o f marine b e n t h i c communities. Neth.J.Sea Res. 3:267-293 T r a n t e r , D.E. and J.H. F r a s e r ( e d s . ) . 1968. Z o o p l a n k t o n s a m p l i n g . UNESCO Monographs on oceanographic methodology, No. 2, UNESCO, P a r i s . T u l l y , J.P. and A . J . Dodimead. 1957- P r o p e r t i e s o f t h e water i n t h e S t r a i t o f G e o r g i a , B r i t i s h Columbia, and i n f l u e n c i n g f a c t o r s . J . F i s h . R e s . Bd.Can. 14:241-319 V i n o g r a d o v a , N.G. 1959. The z o o g e o g r a p n i c a l d i s t r i b u t i o n o f t h e deep water bottom f a u n a i n t h e a b y s s a l zone o f t h e ocean. Deep-Sea Res. 5:205-208 V.yshkvartseva, N.V. and B.L. Gutel'makher. 1971. T r a p p i n g a b i l i t y o f t h e f i l t e r i n g a p p a r a t u s o f some C a l a n i d a e . H y d r o b i o l . J . 7:58-63 Waldichuk, M i c h a e l . 1957- P h y s i c a l oceanography o f t h e S t r a i t o f G e o r g i a , B r i t i s h Columbia. J.Fish.Res.Bd.Can. 14:321-486  142  W a l l a c e , J.VT. and R.S. Bader. I 9 6 7 . F a c t o r a n a l y s i s o f morphometric i n t h e house mouse. S y s t . Z o o l . 16:144-152  traits  W a l o f f , Z. 1966. The upsurges and r e c e s s i o n s o f t h e d e s e r t l o c u s t : an h i s t o r i c a l s u r v e y . A n t i l o c u s t . M e m . No. 8 , Lond. O r i g i n a l n o t seen, c i t e d by Odum ( 1 9 7 1 ) Wang, Dong-Ping and J . J . Walsh. 1 9 7 6 . O b j e c t i v e a n a l y s i s o f t h e u p w e l l i n g system o f f B a j a , C a l i f o r n i a . J.Mar.Res. 34:43-60 W e l l i n g t o n , W.G. 1 9 5 7 . I n d i v i d u a l d i f f e r e n c e s as a f a c t o r i n p o p u l a t i o n dynamics: t h e development o f a problem. C a n . J . Z o o l . 35:293^323 . i 9 6 0 . Q u a l i t a t i v e changes i n n a t u r a l p o p u l a t i o n s d u r i n g i n abundance. C a n . J . Z o o l . 3 8 : 2 8 9 - 3 1 4  changes  W h i t t a k e r , R.H. and H.G. Gauch, J r . 1973- E v a l u a t i o n of o r d i n a t i o n t e c h n i ques. Ghpt. 11 i n W h i t t a k e r , R.H. ( e d . ) , O r d i n a t i o n and c l a s s i f i c a t i o n o f communities. D r . W. Junk b-v, P u b l i s h e r s , The Hague. 737PP Wiebe, P.H. 1 9 7 0 . S m a l l - s c a l e s p a t i a l d i s t r i b u t i o n i n o c e a n i c z o o p l a n k t o n . Limnol.Oceanogr. 15:205-217  net  and W.R. H o l l a n d . 1 9 6 8 . P l a n k t o n p a t c h i n e s s : e f f e c t s on r e p e a t e d tows. Limnol.Oceanogr. 13:315-321  W i l l i a m s o n , M.H. I 9 6 I . An e c o l o g i c a l s u r v e y o f a S c o t t i s h h e r r i n g f i s h e r y . P a r t IV: Changes i n t h e p l a n k t o n d u r i n g t h e p e r i o d 1 9 4 9 - 1 9 5 9 B u l l . M a r . E c o l . 5:207-229 . 1 9 6 3 . The r e l a t i o n of p l a n k t o n t o some parameters o f t h e h e r r i n g p o p u l a t i o n o f t h e n o r t h - w e s t e r n N o r t h Sea. Rapp.P-V.Reun.Cons. int.Explor.Mer 154:179-185 W i l s o n , D.P. 1 9 5 1 . A b i o l o g i c a l d i f f e r e n c e between n a t u r a l s e a w a t e r s . J . Max. b i o l . A s s o c . U-^K. 30:1-19 and F.A.J. Armstrong. 1 9 5 8 . B i o l o g i c a l d i f f e r e n c e s between s e a w a t e r s : e x p e r i m e n t s i n 1954 and 1 9 5 5 . J.mar.biol.Assoc.U.K. 37:331-348 W i l s o n , D.P. and F.A.J. Armstrong. 1961. B i o l o g i c a l d i f f e r e n c e s between s e a waters: experiments i n i 9 6 0 . J.mar.biol.Assoc.U.K. 41:663-681 Winberg, G.G. 1 9 5 6 . R a t e o f metabolism and f o o d r e q u i r e m e n t s of f i s h e s . Nauchyne Trudy B a l u r u s s k o v o Gosudaruennovo U n i v e r s i t a t a i m e n i V.L. L e n i n a , Minsk. 253pp (Fish.Res.Bd.Can., T r a n s l . S e r . No. 194) W i s s i n g , T.R., R.M. MacDonald, Mohamed A. I b r a h i m and Leo B e r n e r . 1973C a l o r i f i c v a l u e s o f marine a n i m a l s from t h e G u l f o f M e x i c o . G o n t r i b . i n M a r . S c i . 17:1-9  143  Woodhouse, C D . 1971. A s t u d y o f t h e e c o l o g i c a l r e l a t i o n s h i p s and t a x o n o mic s t a t u s o f two s p e c i e s o f t h e genus C a l a n u s (Crustacea:Copepoda). Ph.D. T h e s i s , I n s t i t u t e o f Oceanography and Department o f Z o o l o g y , U n i v e r s i t y o f B r i t i s h Columbia. Z i l l i o u x , E . J . and D.F. W i l s o n . I966. C u l t u r e o f a p l a n k t o n i c c a l a n p i d copepod t h r o u g h m u l t i p l e g e n e r a t i o n s . S c i e n c e 151:996-998  144  APPENDIX A The p r o p e r i d e n t i f i c a t i o n of marine z o o p l a n k t o n time-consuming p r o c e s s .  is a difficult  and  P u b l i s h e d d e s c r i p t i o n s commonly d i s c u s s o n l y  one  stage i n d e t a i l ( e . g . D a v i s 1949; M o r i 1964; B r o d s k y 1967; F u l t o n 1968, 19?2,  1973) and many s p e c i e s a r e p o o r l y d e s c r i b e d and d i f f i c u l t t o i d e n -  t i f y accurately.  The amount of work i n v o l v e d i n s a t i s f a c t o r i l y i d e n t i -  f y i n g a l l of t h e s p e c i e s encountered i n my r e s e a r c h would have been p r o hibitive.  F o r my p u r p o s e s , i t was  s u f f i c i e n t t h a t each s p e c i e s be  f i e d as b e s t as p o s s i b l e u s i n g r e a d i l y a c c e s s i b l e d e s c r i p t i o n s .  identi-  In most  cases, and e s p e c i a l l y w i t h t h e copepods, t h i s r e s u l t e d i n i d e n t i f i c a t i o n to the species l e v e l .  T h i s is-mot t o suggest t h a t t h e  identifications  a r e a b s o l u t e ; however, t h e y r e p r e s e n t t h e b e s t i d e n t i f i c a t i o n p o s s i b l e without attempting d e t a i l e d d e s c r i p t i o n s t h a t are best l e f t to  qualified  systematists. The  s y s t e m a t i c s o f P a r e u c h a e t a e l o n g a t a a r e a case i n p o i n t .  This  s p e c i e s has been s t u d i e d and r e f e r r e d t o i n t h e S t r a i t of G e o r g i a  under  two names: Euchaeta j a p o n i c a Marukawa ( e . g . Campbell 1934; L e w i s and  Ram-  n a r i n e 1969; L e w i s e t a l . 1971, 1972) and P a r e u c h a e t a e l o n g a t a E s t e r l e y (Evans 1973)•  The t y p e specimens a r e l o s t , t h e o o r i g i n a l d e s c r i p t i o n s  are vague and even t h e v a l i d i t y o f t h e genus P a r e u c h a e t a has been c h a l l e n ged . I have used t h e name P a r e u c h a t a  e l o n g a t a on t h e b a s i s of arguments  advanced by Evans (1973)» but t h e c o n t r o v e r s y i s not y e t r e s o l v e d . The nomenclature of C a l a n u s s p e c i e s i s another and u n c e r t a i n t y .  example of c o n f u s i o n  C a l a n u s plumchrus was r e f e r r e d t o as C. t o n s u s f o r much  of t h i s c e n t u r y ( e . g . Campbell 1933, 1934; see Gardner 1972 f o r a more complete aceo.unt^.ionWoodhouse (1971) was  the f i r s t to describe Calanus  145  g l a c i a l i s and G. p a c i f i c u s a s s e p a r a t e s p e c i e s i n t h i s a r e a .  Previously  t h e y had been c o n s i d e r e d a s i n g l e s p e c i e s and o f t e n r e f e r r e d t o a s C a l a n u s finmarchicus.  C a l a n u s g l a c i a l i s i n t h e N o r t h P a c i f i c has s i n c e been r e d e -  f i n e d by F r o s t (1974) a s a new s p e c i e s , C a l a n u s m a r s h a l l a e , which i s r & u r e a d i l y d i s t i n g u i s h e d from t r u e C. g l a c i a l i s ( F r o s t , p e r s . comm.). These examples a r e o f s p e c i e s t h a t a r e among t h e most s t u d i e d s p e c i e s i n the S t r a i t of Georgia. examined.  Many o f t h e o t h e r s p e c i e s have n e v e r been c l o s e l y  A l t h o u g h p r o g r e s s i s b e i n g made, i t w i l l r e q u i r e a major e f f o r t  to b r i n g the systematics of t h e l o c a l zooplankton  t o t h e p o i n t where i n -  d i v i d u a l s p e c i e s can be„confidently i d e n t i f i e d i n a l l t h e i r l i f e stages.  U n t i l t h i s g o a l i s reached,  q u a l i f i e d and n o t regarded  history  most s p e c i e s i d e n t i f i c a t i o n s must be  as a b s o l u t e .  

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.831.1-0094027/manifest

Comment

Related Items