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Effects of changes in temperature, salinity and undefined properties of sea water on the respiration… Gilfillan, Edward Smith 1970

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THE  EFFECTS OF CHANGES IN TEMPERATURE, SALINITY AND UNDEFINED  PROPERTIES OF SEA WATER ON THE RESPIRATION OF EUPHAUSIA PACIFICA HANSEN (CRUSTACEA) IN RELATION TO THE SPECIES' ECOLOGY. by Edward Smith G i l f i l l a n  J  A THESIS SUBMITTED IN PARTIAL FULFILMENT* )OF 1  THE  REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY  i n the Department of ZOOLOGY and INSTITUTE OF OCEANOGRAPHY  We accept this thesis as conforming to the required standard  THE UNIVERSITY OF BRITISH COLUMBIA July, 1970  In presenting this thesis in partial fulfilment of the requirements for an advanced degree at the University of British Columbia, I agree that the Library shall make i t freely available for reference and study. I further agree that permission for extensive copying of this thesis for scholarly purposes may be granted by the Head of my Department or by his representatives.  It is understood that copying or publication  of this thesis for financial gain shall not be allowed without my written permission.  Department of The University of British Columbia Vancouver 8, Canada  i Chairman: Dr. B. McK. Bary ABSTRACT  Temperature, s a l i n i t y , and other, undefined properties of sea water have been suggested as factors acting to l i m i t the  d i s t r i b u t i o n of planktonic organisms through the stresses  they impose.  The aim of this study was to examine experimentally  the effects of changes i n these properties on the respiration of Euphausia p a c i f i c a Hansen.  Both immediate and long term  effects of changes i n these properties were examined. Assessments of the immediate effects of changes i n temperature and s a l i n i t y on the animals' respiratory rate demonstrated that a sharp reduction i n respiratory rate could be used as an indication of stress.  The results of these same  experiments showed that as the values of temperature and s a l i n i t y approached the l i m i t s of tolerance, the effects of stresses from them i n t e r a c t . The long term effects of changes i n temperature and s a l i n i t y were investigated by determining the l i m i t s of these factors that were tolerable to specimens from areas i n which the  c h a r a c t e r i s t i c temperatures and s a l i n i t i e s of the water  were d i f f e r e n t .  Specimens from the water having the greatest  range of values of temperature and s a l i n i t y the  (coastal) possessed  greatest tolerance to changes i n temperature and s a l i n i t y ;  specimens from water having the least range of temperature and s a l i n i t y  (oceanic)'had the least tolerance.  The tolerances  to changes i n temperature and s a l i n i t y observed i n these experiments indicated that the d i s t r i b u t i o n of E_. p a c i f i c a i n B r i t i s h Columbia coastal waters was not l i k e l y to be  ii  influenced by changes i n temperature and s a l i n i t y except near the surface, where the s a l i n i t y may become low and the temperature high or very low. Experiments taking advantage of the i n t e r a c t i o n between the e f f e t t s of temperature and s a l i n i t y were used to establish that other properties of sea water, while undefined, could impose stress on adult E_. p a c i f i c a .  At the same time a method  of assessing the effects of changes i n undefined properties between sea waters through a comparison of respiratory rates obtained under standard conditions was developed. The results of experiments i n which changes i n undefined properties of sea waters c o l l e c t e d at two depths i n each of two locations were examined indicate that these properties appear to be a function of the o r i g i n of the p a r t i c u l a r water.  They  also indicate that differences between waters i n these properties did not affect the d i s t r i b u t i o n of jE. p a c i f i c a within either of the two areas investigated,nnamely the S t r a i t of Georgia and Indian Arm.  The results did i n d i c a t e , however, that populations  of E. p a c i f i c a were present i n each of these areas i n which inverse reactions to the same set of undefined properties existed.  Presumably these result from persistent differences  i n undefined properties between the waters resident i n each of the two areas.  iii TABLE OF CONTENTS Page I.  II.  GENERAL INTRODUCTION  1  GENERAL MATERIALS AND METHODS  8  F i e l d Procedures  III.  Laboratory Procedures  11  Respiration Measurements  11  OCEANOGRAPHIC CONDITIONS IN THE SAMPLING AREAS . . . Northeastern P a c i f i c Ocean  IV.  8  . . . . . . .  15 20  Juan de Fuca S t r a i t  22  Saanich Inlet  22  The S t r a i t of Goergia  24  Indian Arm  28  THE EFFECTS OF STRESS FROM CHANGES IN TEMPERATURE AND SALINITY ON SPECIMENS FROM OCEANIC, OCEANICCOASTAL AND COASTAL WATERS Introduction  32  Materials and Methods  34  Results  35  Discussion V.  32  . . . . .  41  THE EFFECTS OF SEVERAL NATURAL SEA WATERS ON TOLERANCE TO VARIATIONS IN TEMPERATURE AND SALINITY  49  Introduction . . .  49  Materials and Methods  51  iv  TABLE OF CONTENTS (continued) Page  VI.  S t a t i s t i c a l Analysis  54  Results  55  Dis cussion  62  ANNUAL CHANGES IN THE REACTIONS OF TWO COASTAL POPULATIONS OF EUPHAUSIA PACIFICA TO NATURAL SEA WATERS Introduction  69 . . . . . . . . . . .  Materials and Methods Results Discussion VII. VIII.  GENERAL DISCUSSION  69 72  •  75 80 97  SUMMARY AND CONCLUSIONS  105  IX.  REFERENCES  109  X.  APPENDIX 1  115  V  LIST OF TABLES Table  Subject  Page  Depths at which observations of water properties were made and plankton samples were collected i n the S t r a i t of Georgia (Station G.S.-l) and i n Indian Arm (Station I.A.-9) 2.  3.  4.  5.  6.  7.  8.  9.  Results of analysis of variance: Reactions of Euphausia p a c i f i c a from Saanich Inlet to changes i n temperature and s a l i n i t y , data from February 1969 and June 1969 combined . .  38  Results of analysis of variance: Reactions of Euphausia p a c i f i c a from Juan de Fuca S t r a i t to changes i n temperature and s a l i n i t y , data from November 1968 and July 1969 combined  39  Results of analysis of variance: Reaction of Euphausia p a c i f i c a from the P a c i f i c Ocean to changes i n temperature and s a l i n i t y , data from February 1969 and June 1969 combined  40  The depth of c o l l e c t i o n and the s a l i n i t y of sea water samples from Indian Arm and the S t r a i t of Georgia used i n the experiments carried out i n May, July and August, 1969  53  Results of analysis of variance: Reaction of Euphausia p a c i f i c a from the S t r a i t of Georgia to changes i n temperature, s a l i n i t y and 'other' water properties, data from the experiment performed i n May 1969  58  Results of-analysis of variance: Reactions of Euphausia p a c i f i c a from the S t r a i t of Georgia to changes i n temperature, s a l i n i t y and 'other' water properties, data from the experiment performed i n July 1969 . . . , |  60  Results of analysis of variances Reactions of Euphausia p a c i f i c a from the S t r a i t of Georgia to changes i n temperature, s a l i n i t y and 'other' water properties, data from the experiment performed i n August 1969  63  Temperatures, s a l i n i t i e s , and depths from which the two waters used i n experiments were collected from Indian Arm  73  vi LIST OF TABLES (continued) Table 10.  11.  12.  13.  14.  15.  16.  17.  18.  Subject  Page  Temperatures, s a l i n i t i e s , and depths from which the two waters used i n experiments were c o l l e c t e d i n the S t r a i t of G e o r g i a  74  R e s u l t s of a n a l y s i s of v a r i a n c e ; A n a l y s i s of a l l data o b t a i n e d over 13 months u s i n g Euphausia p a c i f i c a from both I n d i a n Arm and the S t r a i t of G e o r g i a i n f o u r sea waters . . . .  81  R e s u l t s o f a n a l y s i s of v a r i a n c e : R e a c t i o n s of Euphausia p a c i f i c a from I n d i a n Arm t o I n d i a n Arm upper and lower water over 13 months  82  R e s u l t s o f a n a l y s i s o f v a r i a n c e : R e a c t i o n s of Euphausia p a c i f i c a from the S t r a i t of G e o r g i a t o S t r a i t of G e o r g i a upper and lower water d u r i n g 'low s a l i n i t y , ' c o n d i t i o n s i n 1968 ( A p r i l , May) and i n 1969 (May, June)  83  R e s u l t s of a n a l y s i s of v a r i a n c e ; R e a c t i o n s of Euphausia p a c i f i c a from the S t r a i t of G e o r g i a to S t r a i t of G e o r g i a upper and lower waters d u r i n g 'high s a l i n i t y ' c o n d i t i o n s , w i n t e r 1968-1969 (November, December, January, February)  84  R e s u l t s of a n a l y s i s of v a r i a n c e : R e a c t i o n s of Euphausia p a c i f i c a from I n d i a n Arm t o S t r a i t of G e o r g i a upper, S t r a i t of G e o r g i a lower, and I n d i a n Arm composite waters d u r i n g August, September, and October 1968 compared w i t h those d u r i n g J u l y , August, and September 1969.  85  R e s u l t s of a n a l y s i s of v a r i a n c e ; R e a c t i o n s of Euphausia p a c i f i c a from I n d i a n Arm t o S t r a i t of G e o r g i a upper, S t r a i t of G e o r g i a lower, and I n d i a n Arm composite waters d u r i n g February, March, A p r i l and May 1969  86  R e s u l t s o f a n a l y s i s of v a r i a n c e : R e a c t i o n s of Euphausia p a c i f i c a from I n d i a n Arm t o S t r a i t of G e o r g i a upper, S t r a i t o f G e o r g i a lower, and I n d i a n Arm composite waters d u r i n g June, J u l y , August and September 1969  87  R e s u l t s of a n a l y s i s of v a r i a n c e : R e a c t i o n s of Euphausia p a c i f i c a from I n d i a n Arm t o S t r a i t o f G e o r g i a upper, S t r a i t of G e o r g i a lower, and I n d i a n Arm composite water d u r i n g the p e r i o d o f February, March, A p r i l and May 1969 compared w i t h t h e i r r e a c t i o n s t o the same waters d u r i n g the p e r i o d June, J u l y , August and September 1969  88  vii LIST OF TABLES (continued) Table 19.  i  Subject  Page  . Abundance of adult and juvenile Euphausia p a c i f i c a as numbers/m3 at Indian Arm Station 9: data from plankton samples c o l l e c t e d using the Clarke-Bumpus Plankton samplers  89  viii  LIST OF FIGURES Figure  Subject  1.  A t y p i c a l oxygraph r e c o r d showing, A, a r e g i o n of thermal e q u i l i b r a t i o n between the e l e c t r o d e and the f r e s h medium; B, a r e g i o n o f l i n e a r decrease. The s l o p e o f the r e g i o n of l i n e a r decrease (H/time) was used t o c a l c u l a t e the animals' r e s p i r a t i o n r a t e s  14  O v e r a l l t e m p e r a t u r e - s a l i n i t y diagram, showing the i n t e r r e l a t i o n s o f the waters p r e s e n t i n the areas from which e u p h a u s i i d s were collected.  16  Chart o f B r i t i s h Columbia c o a s t a l waters showing p o s i t i o n s o f s t a t i o n s from which e u p h a u s i i d s were c o l l e c t e d  18  Temperature and s a l i n i t y v a l u e s observed at s t a t i o n P a c . - l i n February and June 1969, p l o t t e d as t e m p e r a t u r e - s a l i n i t y diagrams. . .  21  Temperature and s a l i n i t y v a l u e s observed a t s t a t i o n J.F.-9 i n November 1968 and J u l y 1969, p l o t t e d as t e m p e r a t u r e - s a l i n i t y diagrams. . .  23  Temperature and s a l i n i t y v a l u e s observed at s t a t i o n SAA-4 i n February and June 1969, p l o t t e d as t e m p e r a t u r e - s a l i n i t y diagrams. . .  25  Temperature p l o t t e d a g a i n s t depth a t s t a t i o n G.S.-l from August 1968 to September 1969 . .  27  S a l i n i t y p l o t t e d a g a i n s t depth at s t a t i o n G.S.-l from August 1968 to September 1969  27  Temperature p l o t t e d a g a i n s t depth a t s t a t i o n I.A.-9 from-August 1968 to September 1969 . .  29  S a l i n i t y p l o t t e d a g a i n s t depth at s t a t i o n I.A.-9 from August 1968 t o September 1969  29  2.  3.  4.  5.  6..  7.  8.  9.  10.  ll(a-c).  Page  R e s p i r a t i o n - s a l i n i t y curves f o r Euphausia p a c i f i c a under v a r i o u s combinations o f temperature and s a l i n i t y , a. Specimens from Saanich I n l e t , d a t a c o l l e c t e d i n February and June 1969. b. Specimens from Juan de F u c a S t r a i t , d a t a c o l l e c t e d i n November 1968 and J u l y 1969. c. Specimens from the P a c i f i c Ocean, d a t a c o l l e c t e d i n February and June 1969 36  ix  LIST OF FIGURES (continued) Figure  Subject  12(a-c). R e s p i r a t i o n - s a l i n i t y curves f o r Euphausia p a c i f i c a from the S t r a i t of Georgia while i n media made from 4 sea-waters collected at d i f f e r i n g depths and locations, a. Data from the experiment performed i n May 1969. b. Data from the experiment performed i n July 1969. c. Data from the experiment performed i n August 1969 13a.  13b.  Page  57  Respiration of Euphausia p a c i f i c a from the S t r a i t of Georgia i n S t r a i t of Georgia upper and lower and i n Indian Arm Composite from A p r i l 1968 to September 1969 (Indian Arm Composite from August 1968 to September 1969 only)  75A  Respiration of Euphausia p a c i f i c a from Indian Arm i n S t r a i t of Georgia upper and lower and i n Indian Arm Composite from March 1968 to September 1969  75A  X  ACKNOWLEDGMENTS I am indebted to a l l the members of my research advisory committee for t h e i r guidance and encouragement. I would l i k e to extend my most sincere thanks to my research advisor, Dr. B. McK. Bary, f o r h i s patience, advice, encouragement and c r i t i c i s m . I would also l i k e to thank Dr. C.S. H o l l i n g , Dr. P.A. Larkin, Dr. A.G. Lewis and Dr. G.L. Pickard, a l l of whom read and c r i t i c i s e d the manuscript, f o r t h e i r h e l p f u l suggestions and c r i t i c i s m s .  I would l i k e to offer s p e c i a l  thanks to Dr. A.G. Lewis and Dr. J. Sibert for the many f r u i t f u l discussions i n which they participated. The o f f i c e r s and men of CNAV Laymore, CNAV Endeavour and CSS Vector deserve sincere thanks f o r t h e i r cheerful and generous assistance i n the gathering of the data. To my wife, Katherine, whose encouragement during the research and the preparation of the thesis made these tasks much easier, I offer my most sincere thanks.  THE  EFFECTS OF CHANGES IN TEMPERATURE, SALINITY AND UNDEFINED  PROPERTIES OF SEA WATER ON THE RESPIRATION OF EUPHAUSIA PACIFICA HANSEN (CRUSTACEA) IN RELATION TO THE SPECIES' ECOLOGY.  I.  GENERAL INTRODUCTION. One important question i n the ecology of marine zoo-  planktonic organisms i s "What l i m i t s the d i s t r i b u t i o n of these organisms?".  Answers to this question are usually given i n terms  of a ' l i m i t i n g ' factor or factors.  These generally  are presumed  to impose stress on the animals i n question and thus l i m i t their d i s t r i b u t i o n . Brett  (1958, p. 74) has defined stress as : "... a  state produced by an environmental factor which extends the adaptive response of an animal beyond the normal range, or which disturbs  the normal functioning  to such an extent that, i n  either case, the chances of s u r v i v a l are s i g n i f i c a n t l y reduced". He divides  (p. 75) stresses  f i r s t , discriminate  into two general categories.  The  stress, i s defined as "... one which applies  at any one time to i n d i v i d u a l s , singly within a population and not to a group or stock as a whole". p a r a s i t i c i n f e s t a t i o n , and injury. indiscriminate  Examples are predation, Brett's second category,  s t r e s s , i s "... one which applies  to every  member (of a population) and i s not discrete i n i t s action. Stresses l i k e high temperature, low oxygen, or toxic effluents spare no i n d i v i d u a l entering such c h a r a c t e r i s t i c s . "  or inhabiting an environment with  -2Factors which have been suggested  as l i m i t i n g the  d i s t r i b u t i o n of zooplanktonic organisms, namely the various properties of sea water, are invariably sources of indiscriminate stress.  Much of the information currently available i n r e l a t i o n  to this subject stems from the large body of l i t e r a t u r e concerned with the 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 of so-called 'indicator species'. Indicator species are those whose occurrence i n an area indicates the presence there of water of a p a r t i c u l a r s o r i g i n , i n i t i a l l y from a s p e c i f i c geographic l o c a l i t y Fraser, 1937,  1939,  1952; R u s s e l l , 1935,  1939).  (see  No physico-  chemical characterization of the waters indicated by the species' presence was  attempted i n the studies cited above.  The underlying hypothesis was  that these species were limited  i n their d i s t r i b u t i o n to the water whose presence they indicated because they were unable to l i v e i n any other. Pickford (1946, 1952) bathypelagic squid was  demonstrated that a species of  confined to certain water masses by  p l o t t i n g the temperature (T) and s a l i n i t y (S) values for the depths at which the specimens were captured.  Using the same  technique Haffner (1952) also demonstrated that certain species of bathypelagic f i s h were associated with water masses. general method was  developed  This  and extended by Bary (1959, 19 63a b! ,c d  1964) who worked with surface waters and zooplanktonic  J  J  >  animals.  Bary's technique uses the temperature-salinity-plankton (T-S-P) diagram as a means of i d e n t i f y i n g indicator species by r e l a t i n g t h e i r occurrences sampling  area.  to the 'water bodies' which exist i n the  Studies b'y.9 Eager and McGowan (1963) , and Sherman  1  J  J  -3(1963, 1964)  and Cross and Small (1967) have demonstrated  further the close association between the occurrence of certain species of zooplanktonic i n the  organisms and the water bodies present  area. The i d e n t i t y of the property  or properties of a given  water body that might-limit a species' d i s t r i b u t i o n remains a source of speculation.  Because temperature and s a l i n i t y  are  commonly used to characterize water bodies, i t has been suggested that these properties, either singly or i n combination, might be the operative agents.  Certainly, i n some instances,  there i s no question that they are (see Kinne, 1964, review of the relevant l i t e r a t u r e ) .  Bary (1963  for a  d; 1964),  however, discusses the d i s t r i b u t i o n of zooplanktonic  organisms  from the Northeastern A t l a n t i c i n r e l a t i o n to i d e n t i f i a b l e water bodies and shows that i t does not depend on the temperature and s a l i n i t y values by means of which the water bodies were characterized.  In view of this finding Bary (1963  d, p.  proposed that certain undetermined 'unique properties' e r i s t i c of each water body, combined with the d i f f e r i n g  64)  characttolerances  of various species, could be responsible for the species-water body ^relationship. In searching for an improved culture medium for echinoderm larvae, Wilson (1951) compared experimentally  the  s u i t a b i l i t y of water from the English Channel and the C e l t i c Sea,  two areas frequently characterized by d i f f e r e n t sets of  i n d i c a t o r species. water was  The  results showed that the C e l t i c  Sea  a superior culture medium, a s i t u a t i o n attributed to  ' b i o l o g i c a l differences' between the waters by Wilson.  Further  -4-  experiments  (Wilson and Armstrong, 1952, 1954, 1958, 1961)  i n d i c a t e d t h a t these ' b i o l o g i c a l d i f f e r e n c e s ' were p e r s i s t e n t , b u t f a i l e d t o enable the a c t i v e p r i n c i p l e c a u s i n g the d i f f e r e n c e s to be i d e n t i f i e d .  An e x t e n t i o n i n i n t e r p r e t a t i o n o f r e s u l t s  o b t a i n e d by W i l s o n and Armstrong  from experiments i n which  eggs  were a l l o w e d t o develop i n mixtures o f two waters s u g g e s t e d , however, t h a t the d i f f e r e n t e f f e c t s produced by the two waters r e s u l t e d from the l a c k o f some 'good' o r r e q u i r e d p r o p e r t y i n the 'bad' water, r a t h e r than from the presence o f some t o x i c quality. Lewis  (1967) and Lewis and Ramnarine (1969) r e p o r t  t h a t the s u r v i v a l of eggs and n a u p l i a r s t a g e s of a c a l a n o i d cppepod i n s e a water c o l l e c t e d from depths where they were  living  was i n c r e a s e d by the a d d i t i o n o f t r a c e amounts o f c o b a l t and z i n c , as w e l l as a c h e l a t i n g agent (EDTA).  Their  results  i n d i c a t e t h a t c o b a l t and z i n c a t times may be p r e s e n t i n the 1  i  raw s e a water i n l e s s than o p t i m a l c o n c e n t r a t i o n s . of changes  The e f f e c t  i n the c o n c e n t r a t i o n o f c o b a l t and z i n c on  s u r v i v a l o f l a r v a l copepods  suggests t h a t v a r i a t i o n s i n concen-  t r a t i o n o f t r a c e elements may be among t h e f a c t o r s which affect  the d i s t r i b u t i o n o f p l a n k t o n i c organisms. Regan (1968) c a r r i e d out a s e r i e s of experiments on  a l o c a l s p e c i e s o f e u p h a u s i i d , Euphausia p a c i f i c a Hansen, i n which he demonstrated t h a t b o t h the b e h a v i o u r and s u r v i v a l o f these animals c o u l d be s t r o n g l y a f f e c t e d by the s o u r c e o f the s e a water used as an e x p e r i m e n t a l medium. t h a t specimens  F u r t h e r , he found  o f _E. p a c i f i c a c a p t u r e d i n t h r e e  localities,  -5-  reacted d i f f e r e n t l y to sea waters from several sources.  Regan  explains these results i n terms of 'unique properties' of the waters used as experimental media, rather than i n terms of reactions to temperature and s a l i n i t y , or to a T x S i n t e r a c t i o n . These l a s t causes were ruled out.in the course of h i s experiments. The above b r i e f review of some of the relevant l i t e r a t u r e indicates that the temperature and s a l i n i t y of their environment may affect the d i s t r i b u t i o n of zooplanktonic organisms when extreme values of temperature and s a l i n i t y are approached.  At  the same time, however, many species of zooplanktonic animals are capable of reacting to differences i n some 'essential quality' or 'property' between natural sea waters, of d i f f e r i n g origins but with comparable temperatures and s a l i n i t i e s .  It i s  also indicated that some species may have d i f f e r e n t requirements and/or tolerances f o r these q u a l i t a t i v e differences between sea waters.  And l a s t l y , there i s evidence that a l l members of  a species may not have s i m i l a r requirements or tolerances. Bary (1963 d) summarized the s i t u a t i o n with respect to 'unique properties' by saying that there are two aspects of the ecology of zooplanktonic organisms:  one i s oceanographic -  the properties (not only the 'unique properties',  but also  temperature and s a l i n i t y ) of d i f f e r e n t waters; the other i s b i o l o g i c a l - the species' differing'reactions to changes i n properties between sea waters of d i f f e r i n g h i s t o r i e s .  This  second aspect of the ecology of zooplanktonic organisms appears to be f u l l y as important as the f i r s t ; i t has, however, rarely been investigated experimentally (Kinne, 1964).  I t could  -6-  be expected therefore that the results of a series of experiments directed toward understanding the way a l o c a l species of zooplankton, Euphausiarfeacifica Hansen, reacts to different properties of sea water, would provide an insight into the ecology of planktonic organisms. To this end, three lines of research were pursued. The aim of the f i r s t was to investigate the effects of changes i n temperature and s a l i n i t y ,  of known sources of stress  which can be measured and manipulated experimentally, on specimens of E_. p a c i f i c a .  In order to pursue this object i t  was necessary to develop a means of assaying for effects of sublethal stress which i n turn was used to determine the point at which specimens, collected from oceanic, mixed oceanic-coastal and coastal waters, became affected by stress from elevated temperatures and reduced s a l i n i t i e s .  I t should be possible  from a, comparison of the reactions of specimens resident i n each of the three waters to i n f e r whether and to what extent adaptation to changes i n environmental conditions had occurred.  .  i The second aim of the experiments was to useuthe knowledge  gained about E_. p a c i f i c a ' s reactions to stress imposed by changes i n temperature and s a l i n i t y , to investigate the effects of water properties other than temperature and s a l i n i t y on the animal's metabolism. • An i n t e g r a l part of the experiments was to develop a method of evaluating the r e l a t i v e amounts of stress exerted on specimens by differences i n 'other' properties between sea waters.  -7The  t h i r d aim has been to relate changes i n the  d i s t r i b u t i o n of non-measurable properties ('other'properties ' ) from month to month at two locations, to changes i n the oceanographic processes.  An analysis of the results of this  t h i r d part of the program indicates what relationship exists between the d i s t r i b u t i o n of the 'other' properties' and d i s t r i b u t i o n of E_. p a c i f i c a and whether adaptation  the  to the  unique combination of 'other'properties' of a given water body can occur. Each of these objectives was  approached by measuring  the respiratory rate of i n d i v i d u a l specimens of _E. p a c i f i c a in sea water under a variety of conditions. In general, the results of the investigations indicate that both temperature and s a l i n i t y , as w e l l as 'other' properties of sea water can place adult E_. p a c i f i c a under stress. further indicate that adaptation  They  to environments which d i f f e r  both with respect to their temperature-salinity c h a r a c t e r i s t i c s and their 'other' properties has waters.  occurred i n B.C.  coastal  -8-  II.  GENERAL MATERIALS AND  Euphausia and i n s h o r e areas Regan, 1968; appears  METHODS.  p a c i f i c a i s w i d e l y d i s t r i b u t e d i n both o f f s h o r e ( B r i n t o n , 1962;  Mauchline  Ponomareva, 1963;  Bary,  1966;  and F i s h e r , 1969);jon t h i s b a s i s i t  to be a h i g h l y t o l e r a n t s p e c i e s .  Even so, i t has  demonstrated t h a t specimens r e a c t b e h a v i o u r a l l y (Regan,  been 1968)  to d i f f e r e n c e s i n p r o p e r t i e s between water b o d i e s ; specimens a l s o are l a r g e , g e n e r a l l y abundant, and laboratory handling.  tolerant  toward  For these reasons E_. p a c i f i c a i s a good  e x p e r i m e n t a l animal w i t h which to study  the r e l a t i o n between  the s p e c i e s and the water i n which i t l i v e s .  Field  Procedures. Each s t a t i o n from which e x p e r i m e n t a l animals were  c o l l e c t e d was There were two  o c c u p i e d , whenever f e a s i b l e , by day aims:  firstly,  and by n i g h t .  to o b t a i n data withhwhichoto  r e l a t e the e x p e r i m e n t a l r e s u l t s to the daytime d i s t r i b u t i o n of _E. p a c i f i c a and s e c o n d l y , to c o l l e c t c e x p e r i m e n t a l animals  at  n i g h t when they were c l o s e to the s u r f a c e and l e s s l i k e l y  to  be  damaged i n the s h o r t e n e d  o b s e r v a t i o n s of temperature depths  a t each s t a t i o n  tows made then.  During  daylight,  and s a l i n i t y were made at s e l e c t e d  (Table 1).  H o r i z o n t a l p l a n k t o n tows  a l s o were made u s i n g Clarke-Bumpus p l a n k t o n samplers and Bumpus, 1950)  spaced  at 25 m i n t e r v a l s  (Clarke  (Table 1), i n o r d e r  to a s c e r t a i n the daytime d i s t r i b u t i o n of e u p h a u s i i d s .  -9-  TABLE  1  Depths at which observations of water properties were made and plankton samples were collected i n the S t r a i t of Georgia (Station G.S.-l) and i n Indian Arm (Station I.A.-9).  Stn. G.S. - 1  Stn. I.A. - 9  (depth = 400m)  (depth = 220m)  water prop.  plankton samp.  water prop.  plankton samp,  0  25  0  25  10  50  10  50  20  75  20  75  30  100  30  100  50  125  50  125  75  150  75  150  100  175  100  175  150  200  125  200  250  150  250  300  175  300  350  200  350  375  375  -tOSea w a t e r f o r use i n experiments was a l s o o b t a i n e d d u r i n g d a y l i g h t ; t h u s , e x p e r i m e n t a l r e s u l t s , the daytime d i s t r i b u t i o n o f 13. p a c i f i c a and the d i s t r i b u t i o n o f w a t e r p r o p e r t i e s c o u l d be r e l a t e d . v a r i o u s d e p t h s , depending  The w a t e r was c o l l e c t e d  from  on the l o c a t i o n and the d i s t r i b u t i o n  o f E_. p a c i f i c a , u s i n g a 1 6 - l i t r e Van Dorn Sampler.  I t was  f i l t e r e d through n y l o n mesh h a v i n g a mesh a p e r t u r e o f 160 m i c r a i n t o 2 0 - l i t r e p o l y e t h y l e n e carboys and p l a c e d i n the s h i p ^ s refrigerator until  used.  Specimens o f E_. p a c i f i c a were caught i n v e r t i c a l o r o b l i q u e n e t h a u l s u s i n g a c o n i c a l s a m p l e r , 1-m diameter a t the mouth.  The b u c k e t o f t h i s sampler was a PVC tube, c l o s e d a t  one end, and a p p r o x i m a t e l y 9 x 45 cm i n i n t e r n a l  dimensions.  I t a i d e d i n c o l l e c t i n g specimens i n good c o n d i t i o n by p r o v i d i n g a r e l a t i v e l y non-turbulent refuge during towing. At the s u r f a c e the c o l l e c t i o n was i m m e d i a t e l y  poured  i n t o s e v e r a l l i t r e s o f s e a w a t e r c h i l l e d t o a temperature a p p r o a c h i n g t h a t o f t h e w a t e r i n which they were l i v i n g .  The  animals r e q u i r e d f o r e x p e r i m e n t a l purposes were then t r a n s f e r r e d i n t o 4 - l i t r e vacuum f l a s k s ( i s o t h e r m s ) .  A l l t r a n s f e r s were  made u s i n g s t a i n l e s s s t e e l spoons; the animals were  always  immersed i n w a t e r . I n s e l e c t i n g e x p e r i m e n t a l animals b o t h l a r g e and s m a l l e u p h a u s i i d s were a v o i d e d w i t h the i n t e n t i o n o f o b t a i n i n g animals a p p r o x i m a t i n g a s i n g l e s i z e c l a s s .  U s u a l l y twenty  specimens were p l a c e d i n each i s o t h e r m , :L.e. about 5 / l i t r e . The m o r t a l i t y r a t e was low, p r i m a r i l y because i t was u s u a l l y  easy to d e t e c t capture.  The  and  d i s c a r d an i n d i v i d u a l damaged  during  c u t i c l e of i n j u r e d specimens appeared ' f r o s t y '  at the p o i n t of i n j u r y i n sharp c o n t r a s t t o i t s normal, g l a s s y appearance. ship's  The  specimens were h e l d at 5-10  r e f r i g e r a t o r u n t i l required.  acclimation hours of  I n most  to e x p e r i m e n t a l treatments was  °C i n  the  instances  started within  12  capture.  L a b o r a t o r y P r o c e d u r e s. The  medium f o r many experiments was  water; f o r o t h e r s , media were made up by  f u l l - s t r e n g t h sea  d i l u t i n g the  full-  strength  s e a water w i t h d i s t i l l e d water (from a B a r n s t e a d  still).  Each medium was  polyethylene  b o t t l e and  temperature r e q u i r e d  placed cooled  i n a 1 - l i t r e wide mouthed or warmed to n e a r the  final  f o r the subsequent experiment.  e x p e r i m e n t a l animals were then p l a c e d  The  i n the b o t t l e s and  whole immersed i n a 1 0 0 - l i t r e water b a t h , which was  the  thermo-  s t a t i c a l l y m a i n t a i n e d at the e x p e r i m e n t a l temperature, f o r an a c c l i m a t i o n p e r i o d of 12 h o u r s . p l a c e d i n each b o t t l e so as acclimation which was was  ( r a r e ) and  U s u a l l y seven animals were  to allow  for mortality  losses during handling.  Any  s u s p e c t e d of h a v i n g been damaged d u r i n g  during animal handling  discarded.  R e s p i r a t i o n Measurements. R e s p i r a t i o n measurements were made i n a w a t e r - j a c k e t e d chamber made of g l a s s . 4.9  ml;  i t was  The  i n t e r n a l volume of the  d i v i d e d i n t o two  compartments by  p a r t i t i o n made of s t a i n l e s s s t e e l . was  The  chamber  a wire-mesh  s t o p p e r of the  vented through a c a p i l l a r y b o r e so as t o e q u a l i z e  when i t was  pushed home.  was  chamber pressure  -12When determining respiratory rates, experimental animals were placed on one side of the mesh p a r t i t i o n , and a magnetic s t i r r i n g bar and a polarigraphic oxygen electrode"*" on the other.  This arrangement allowed continuous c i r c u l a t i o n  of the medium without any damage to the animal.  The chamber  and electrode were maintained at the experimental temperature by c i r c u l a t i n g water from the water bath through the water jacket.  The current produced by the electrode i s proportional  to the oxygen content'of the water i n the chamber; i t was  2 continuously recorded on a GME  Oxygraph, model KM.  The  recordings provide a plot of oxygen concentration i n the chamber versus time, f o r each animal. The electrode was  calibrated i n air-saturated water  against Winkler determinations of oxygen content.  Frequent  checks showed that i t , and the recorder, were stable.  One  electrode was used for a l l respiration measurements; i t s c a l i b r a t i o n did not appear to be affected by changing the teflon membrane (.001") i n d i c a t i n g that the membranes were uniform i n thickness.  One batch of membranes was used through-  out this study which may have contributed to the s t a b i l i t y of the electrode. The medium i n which the respiration rate for each animal was determined was  fresh medium s i m i l a r to that i n which  they had been acclimated for 12 hours.  Between the recordings  1.  Yellow Springs Instrument Company, Yellow Springs, Ohio.  2.  Gilson Medical E l e c t r o n i c s , Middleton, Wisconsin.  of rates, when the same medium was being used, the chamber was  flushed with several volumes of fresh medium to remove any  traces of metabolites. chamber was  Between series i n d i f f e r e n t media the  flushed f i r s t with d i s t i l l e d water, and then with  several volumes of the new medium. Recordings of change i n oxygen content of the water i n the chamber, as a result of. the respiration of specimens, were carried out for a period of between 15 and 30 minutes.  After  a s u f f i c i e n t l y long record had been obtained, the specimen was removed from the chamber, using clean s t a i n l e s s - s t e e l forceps, and examined under a dissecting microscope to ensure that i t was JE. p a c i f i c a .  I t was  then fixed for a few minutes i n f u l l -  strength formalin, b l o t t e d dry, and placed i n a sealed v i a l with a code number.  Specimens were l a t e r freeze-dried to a  constant weight. Respiration rates were calculated by  convertingcihe  slope of the l i n e on the oxygraph record (Fig. 1) to m i c r o l i t r e s of oxygen consumed i n an hour and then dividing that value by the freeze-dried weight of the experimental  animal.  In  converting the slope of the oxygraph record to the volume of oxygen respired, account was  taken of the e f f e c t of changes i n  temperature on the amount of current produced per unit oxygen content of the chamber.  The f i n a l value of the respiration  rate for each of the experimental subjects i s expressed  as  microlitres of oxygen consumed per milligram dry weight of euphausiid per hour. These values are reported for each of the experimental  subjects i n Appendix 1.  15 minutes  F i g u r e 1. A t y p i c a l oxygraph. r e c o r d showing, A, a r e g i o n of t h e r m a l e q u i l i b r a t i o n between the f r e s h medium and the e l e c t r o d e ; B, a r e g i o n o f l i n e a r d e c r e a s e . The s l o p e o f the r e g i o n o f l i n e a r decrease (H / time) was used to c a l c u l a t e the animals' r e s p i r a t i o n r a t e .  III.  OCEANOGRAPHIC CONDITIONS IN THE  The  o b j e c t of t h i s study was  SAMPLING AREAS.  t o i n v e s t i g a t e the r e a c t i o n s  of .E. p a c i f i c a from s e v e r a l a r e a s , r a n g i n g from o c e a n i c to c o a s t a l waters,  t o changes i n b o t h measurable (temperature  and  s a l i n i t y ) and non-measurable ('other') p r o p e r t i e s of sea water. At the same time i t was  d e s i r e d t o r e l a t e changes i n r e a c t i o n s  of specimens t o water p r o p e r t i e s t o changes i n the of w a t e r p r o p e r t i e s . to understand  distribution  T h e r e f o r e i t became important not  the g e n e r a l r e l a t i o n  waters i n each of the sampling  to one  another  only  of the  a r e a s , b u t a l s o t o examine  their  p a r t i c u l a r d i s t r i b u t i o n d u r i n g the sampling p e r i o d . The  o c e a n i c JE. p a c i f i c a , which may  source o f specimens l i v i n g i n BSC. d u r i n g the day  ( B r i n t o n , 1962)  be  c o n s i d e r e d the  c o a s t a l waters,  are a s s o c i a t e d  w i t h water whose temperature  and  s a l i n i t y v a l u e s f a l l w i t h i n the bounds s p e c i f i e d by Dodimead e t a l . (1963) f o r the deep C e n t r a l S u b a r c t i c Domain. warmer water of comparable s a l i n i t y , m o d i f i e d by and r u n o f f , g i v e s r i s e t o those B.C. i n t h i s study  ( H e r l i n v e a u x and T u l l y ,  F i g u r e 2 shows envelopes temperature-salinity  from data e x t e n d i n g  The  c o a s t a l waters c o n s i d e r e d 1961).  t h a t can bei'.expected i n each  These e n v e l o p e s , which have been  compiled  over a p e r i o d of y e a r s i n c l u d i n g the:-:  p e r i o d d u r i n g which t h i s study was shaped.  insolation  e n c l o s i n g maximum and minimum  combinations  o f the areas s t u d i e d .  Slightly  c a r r i e d out, are roughly f a n -  g r e a t e s t b u l k of the water i n any  one  area, designated  -16-  F l g u r e 2. (facing) O v e r a l l t e m p e r a t u r e - s a l i n i t y diagram, showing the i n t e r r e l a t i o n s of the waters p r e s e n t i n the areas from w h i c h e u p h a u s i i d s were c o l l e c t e d .  10  25  20  15 i  _1  25  _l  35  30 |_  u  40 r  Pacific  1-7  Juan de Fuca Strait Strait of Georgia  Saanich  WZm  Inlet  \  \  5-9  1-4  ~ \ Strait of Georgia  20-  25  1-3  -20  Indian Arm - 9  - Saanich Inlet  /  15-  -15 open ocean surface water  cr  ID I— < - 10  10Juan de Fuca Strait  open ocean deep zone water  5-  Indian  -i  1  r -  "T~ 10  -5  Arm  -i  15  1  1  —  r -  20  SALINITY  r~ 25  %.  -i  30  35  1  1  r -  40  -1.7-  'deep water' i n t h i s s t u d y , i s r e p r e s e n t e d by the shaded areas n e a r the apex ( r e l a t i v e l y h i g h s a l i n i t i e s ) of each o f the 'fans'.  In g e n e r a l the wide v a r i a t i o n s i n temperature and  salinity  a r e c o n f i n e d to the n e a r - s u r f a c e l a y e r s .  indicates  Figure 2  that the deep i n s h o r e waters c o n s i d e r e d i n t h i s study  a p p a r e n t l y r e s u l t from the p r o g r e s s i v e d i l u t i o n of water the deep C e n t r a l S u b a r c t i c Domain ( o c e a n i c w a t e r ) .  from  The  v a l u e s of temperature and s a l i n i t y shown f o r open ocean s u r f a c e water i n F i g . 2 suggest t h a t i t might a l s o c o n t r i b u t e to the deep i n s h o r e w a t e r s .  On the o t h e r hand, Dodimead et: al (1963)  c o n s i d e r s t h a t t r a n s p o r t across the boundary  ( h a l o c l i n e ) between  the o c e a n i c upper and lower zones i n u n i d i r e c t i o n a l l y As w e l l Lane  upward.  (1962) c o n s i d e r s t h a t the o c e a n i c h a l o c l i n e i s  continuous across the c o n t i n e n t a l s h e l f i n the r e g i o n of the mouth of Juan de Fuca S t r a i t . t h a t t h e r e i s communication water  As a r e s u l t i t appears  unlikely  between the open ocean s u r f a c e  (upper zone) and the water e n t e r i n g Juan de Fuca S t r a i t . The ranges o f temperature seen i n the i n s h o r e waters  result  from s e a s o n a l h e a t i n g and c o o l i n g ; those of s a l i n i t y  from s e a s o n a l v a r i a t i o n s i n f r e s h - w a t e r r u n o f f .  On the whole,  t h e r e i s c o n t i n u i t y o f temperature and s a l i n i t y v a l u e s demonstrated between the o f f s h o r e  ( o c e a n i c ) and i n s h o r e  There a r e a l s o i n d i c a t i o n s  of d i s c r e t e  (coastal) waters.  'water b o d i e s ' (Bary,  1963a) c o i n c i d e n t w i t h the s e v e r a l areas.  I t i s to these and  the E_. p a c i f i c a i n h a b i t i n g them t h a t t h i s study i s d i r e c t e d . Juan de Fuca S t r a i t  and the S t r a i t  of G e o r g i a ( F i g . 2,  F i g . 3) t o g e t h e r form'an e s t u a r i n e system which has d e s c r i b e d by H e r l i n v e a u x and T u l l y  (1961).  been  Basically  this  system  -19consists of a deep inflowing layer of oceanic water overlain by a layer of less dense outflowing water.  These two waters are  mixed together and with water from the upper zone of the S t r a i t of Georgia, which includes runoff, i n t i d a l passes through the San Juan and Gulf Islands.  Part of the mixed water flows  seaward to contribute to the upper layer i n Juan de Fuca S t r a i t ; part flows into the S t r a i t of Georgia where i t occupies the lower zone (Waldichuck, 1957).  Part of the mixed water  also flows into Saanich Inlet (Herlinveaux, 1962).  The close  relationship between the deep water In Saanich Inlet and i n the S t r a i t of Georgia i s shown i n F i g . 2.  The surface layers of  Saanich Inlet show l i t t l e d i l u t i o n (Fig. 2) because the i n l e t receives a small amount of runoff (Herlinveaux, 1962) i n sharp contrast to the upper zone of the S t r a i t of Georgia.  These upper  waters receive a large i n f l u x of stored runoff ( c h i e f l y from snow melt water) during the heating season.  Most of the runoff  a f f e c t i n g the southern s t r a i t s i s from the Fraser River (Waldichuck, 1957).  In F i g . 2 i t s effect i s seen as a 'tongue'  of warm d i l u t e water. The o r i g i n of the water i n Indian Arm from water i n the upper zone of the S t r a i t of Georgia i s strongly suggested by Fig. 2 (Gilmartin, 1962).  Because of the shallow (26 m)  s i l l depth, only water from the upper zone of the S t r a i t of Georgia could enter Indian Arm.  This o r i g i n i s supported also  by the fact that none of the intrusions observed between 1956 and the present (Gilmartin, 1962; Regan, 1968) has contained water having a s a l i n i t y greater than 27.52 o/oo.  The influence  -20-  of b o t h s t o r e d and d i r e c t  r u n o f f and of s e a s o n a l h e a t i n g and  c o o l i n g on the upper zone of I n d i a n Arm in  the range o f temperature and  i s apparent i n F i g . 2  '  salinity.  In o r d e r to r e l a t e the e x p e r i m e n t a l r e s u l t s o b t a i n e d w i t h animals from the f i v e areas t o oceanographic c o n d i t i o n s , the p h y s i c o - c h e m i c a l ( t e m p e r a t u r e - s a l i n i t y ) p r o p e r t i e s o f the water column were sampled  at the same time as the e x p e r i m e n t a l  m a t e r i a l (water and animals) was  obtained.  The r e s u l t s o f  these surveys w i l l be d i s c u s s e d s e p a r a t e l y f o r each of the a r e a s . N o r t h e a s t e r n P a c i f i c Ocean ( S t a t i o n Pac-1, 54°15'N,  136°00'W).  The p r i n c i p a l oceanographic s t r u c t u r e s a t t h i s west o f the Queen C h a r l o t t e ,Islands are an upper  station,  zone  ( s e a s o n a l l y m o d i f i e d ) about 100 m i n depth s e p a r a t e d by a h a l o c l i n e from a lower (non-seasonal) zone.  Dodimead e t a l (1963) have  d i v i d e d both the upper and lower zones i n t o a number o f 'domains' which  are b o d i e s o f water w i t h c o n s i s t e n t p r o p e r t i e s ,  and h e h a v i o u r . equivalent  The  to Bary's  'domains' o f the upper zone are p r o b a b l y (1963a) water b o d i e s ; i n the lower zone they  are s u b d i v i s i o n s o f the P a c i f i c S u b a r c t i c Water Mass. p o s i t i o n o f s t a t i o n Pac-1 and the temperature and v a l u e s observed t h e r e i n February 1969 i n F i g . 4 and T-S with  structure  and June  Both  the  salinity  1969,  (shown  diagram^ Helland-Hansen, 1916), are c o n s i s t e n t  the water at Pac-1 b e l o n g i n g t o the deep C e n t r a l S u b a r c t i c  Domain w i t h i n the S u b a r c t i c Water Mass (Dodimead ^ t a l . , 1963).  These T-S  diagrams  ( F i g . 4) demonstrate  the c h a r a c t e r i s t i c  oceanographic f e a t u r e s o f the a r e a ; the p r i n c i p a l  difference  between February and June i s the e f f e c t of s u r f a c e h e a t i n g i n June.  -21-  Figure 4. (facing) Temperature and s a l i n i t y values observed at s t a t i o n Pac.-l i n February and June 1969, plotted as temperature-salinity diagrams.  -18-  F i g u r e 3. (facing) Chart o f B r i t i s h Columbia c o a s t a l waters showing p o s i t i o n s o f s t a t i o n s from which e u p h a u s i i d s were c o l l e c t e d .  SALINITY  %  -22-  Juan de Fuca S t r a i t (Station J..F.-9, F i g . 3) Station J.F.-9 located just outside the mouth of Juan de Fuca S t r a i t (Fig. 3) i n the Juan de Fuca Canyon.  In this  area during the summer months, the predominantly northwesterly winds produce a net offshore transport (divergence) i n the upper layers which results i n upwelling of deeper waters (Tully, 1942). southeast.  In winter the p r e v a i l i n g winds are from the  These produce a net onshore transport (convergence)  (Lane, 1962, 1963). The T-S diagrams(Fig. 5) for the data collected at J.F.-9 i n November 1968 and July 1969, i l l u s t r a t e the s a l i e n t structure of the Juan de Fuca S t r a i t system.  There i s a shallow  mixed layer of outflowing water (A), a mid-depth halocline (B), and an inflowing deep layer of oceanic water (C) .  A major change  between November 1968 and July 1969 i s the greater depth range occupied by the lower zone ('C,  F i g . 5) i n July (100 m to the  bottom of 290 m) over that i n November (250 m to the bottom). This deep water has temperature-salinity characteristics s i m i l a r to water from the upper part of the deep Central Subarctic Domain (Dodimead et_ _al, 1963) and presumably enters the S t r a i t . Saanich Inlet (Station SAA.-4, F i g . 3). Saanich Inlet i s a f j o r d situated on the southeastern coast of Vancouver Island.  I t consists of a basin 24 km long,  having a maximum depth of 234 m behind a s i l l 73 m i n depth at the mouth.  Because of the small amount of runoff entering the  f j o r d at the head, the estuarine c i r c u l a t i o n i s weak (Herlinveaux,  -23-  Figure 5. (facing) Temperature and s a l i n i t y values observed at s t a t i o n J.F.-9 i n November 1968 and July 1969, plotted as temperature-salinity diagrams.  1  -241962) and at depths greater than the s i l l depth the water tends to become stagnant and i t s oxygen content to be reduced to low levels.  P e r i o d i c a l l y intrusions of outside water enter the i n l e t .  These occur when the density of the water above s i l l depth outside the i n l e t exceeds the density of the water below  sill  depth inside the i n l e t , thus encouraging a flow into the deeper waters; at such times the oxygen content of these deeper waters i s increased. Physico-chemical data collected during the present study are shown i n F i g . 6.  Effects of runoff and i n s o l a t i o n are  p l a i n l y evident i n the data f o r June 1969 i n the reduced s a l i n i t y and high temperature of the upper waters. of  Comparison  the T-S curves below 90 m indicates no large change i n T-S  relations such as would have ensued on an i n t r u s i o n ; inspection of  the d i s t r i b u t i o n of dissolved oxygen (not shown) i n the  i n l e t substantiates t h i s . The S t r a i t of Georgia (Station G.S.-l, F i g . _3) • Waldichuck (1957) states that the flushing of the deep water i n the S t r a i t of Georgia depends on events occurring at the  s i l l s , or t i d a l passes; the characteristics of the mixed  water formed there depend, i n part, on the amount of oceanic water present i n the inner portion of the S t r a i t of Juan de Fuca and in part on the amount of sea-water modified by runoff present in  the upper zone of the S t r a i t of Georgia.  I f the seasonal  upwelling o f f the mouth of Juan de Fuca S t r a i t leads to an increased amount of oceanic water entering the S t r a i t i n summer,  -25-  F i g u r e 6. (facing) Temperature and s a l i n i t y v a l u e s observed at s t a t i o n SAA-4 i n February and June 1969, p l o t t e d as t e m p e r a t u r e - s a l i n i t y diagrams.  I  27.0  I  I  28.0  J-7  1  I  1  L  1  29.0 S A L I N I T Y  1 30.0  %  0  1  1— 31.0  -26-  a greater amount of oceanic water could pass into the inner S t r a i t of Juan de Fuca and thence after mixing into the deep zone of the S t r a i t of Georgia.  Thus, a combination of seasonal  upwelling and the seasonal cycle observed i n runoff (Waldichuck, 1957) could give r i s e to the seasonal cycles i n the temperature and s a l i n i t y of S t r a i t of Georgia deep water observed i n the course of this study (Figs. 7, 8). The deep water of the S t r a i t of Georgia i s flushed when i t i s displaced by water of a greater density (Waldichuck, 1957). Waldichuck suggests also that between flushings fresh water i s mixed downward as a result of turbulence produced by the r e l a t i v e l y strong bottom currents observed by Pickard (1956). Changes ensuing on this process would be much slower than by displacement. The data presented i n Figs 7 and 8 shows i n the upper zone a large seasonal v a r i a t i o n i n temperature and a lesser one in salinity.  In the lower zone the seasonal cycle i s evident  as a sharp increase i n s a l i n i t y (Fig. 8) from September  1968  to November 1968, followed by a slower decline i n s a l i n i t y u n t i l August 1969 when another increase occurs.  A similar  pattern i s v i s i b l e i n the temperature d i s t r i b u t i o n ( F i g . 7). Thus, i n the data from the S t r a i t of Georgia displacement of the resident bottom waters appears to be indicated by the sharp increase i n the temperature and s a l i n i t y of the deep water i n late summer.  The slower turbulent mixing could lead to the  slow erosion of the temperature and s a l i n i t y maxima observed beginning i n November-December 1968 and continuing u n t i l JulyAugust  1969.  -27-  Figure 7. (facing) Temperature plotted against depth at s t a t i o n G.S.-l from August 1968 to September 1969.  Figure 8. (facing) S a l i n i t y plotted against depth at s t a t i o n G.S.-l from August 1968 to September 1969.  -28Therefore, i t i s perhaps useful to think of there being two seasons i n the deep zone of the S t r a i t of Georgia.  The 'low  s a l i n i t y ' season occurs during August 1968 and from A p r i l to July 1969. During these periods the deep water of the S t r a i t of Georgia i s diluted by Fraser River runoff (of the previous year) being mixed downward.  In the process the s a l i n i t y maximum  observed i n early winter i s eroded.  'Low s a l i n i t y '  conditions  - obtain when the s a l i n i t y of the deep water i n the S t r a i t of Georgia i s less than 31 o/oo and the temperature less than 9 °C. The second or 'high s a l i n i t y ' season (October 1968 March 1969) i s the period when the influence on the deep waters i s primarily from upwelled oceanic water mixed with S t r a i t of Georgia upper water.  This would be the period following the  displacement of the resident deep water i n late summer.  'High  s a l i n i t y ' conditions obtain when the deep water i n the S t r a i t of Georgia has a s a l i n i t y greater than 31 o/oo and a temperature greater than 9 °C. Indian Arm (Station I.A.-9 , F i g . _3) . Indian Arm i s more or less t y p i c a l  of B.C. fjords  although i t i s narrower and shorter than the average and has a shallower (26 m) s i l l depth (Gilmartin, 1962).  The major  portion of the i n l e t i s a basin with a mean depth of about 200 m. The s t a t i o n , I.A.-9, was located approximately i n the centre of the  deep basin (Fig. 3). Gilmartin (1962) has described the oceanography of  Indian Arm.  There i s a two-layered estuarine system i n which  s t a b i l i t y i s maintained primarily by the s a l i n i t y  structure.  Indian Arm receives a large amount of runoff; therefore the  -29-  Figure 9. (facing) Temperature plotted against depth at s t a t i o n I.A.-9 from August 1968 to September 1969.  Figure 10. (facing) S a l i n i t y plotted against depth at s t a t i o n I.A.-9 from August 1968 to September 1969.  -30-  temperature and s a l i n i t y v a l u e s i n the upper zone  (0-75 m) vary  w i d e l y throughout the y e a r ( F i g s 9 and 10) although i s o l i n e s d e p i c t i n g the d e t a i l s The  of these changes  are not shown i n the f i g u r e s .  temperature' and s a l i n i t y v a l u e s c h a r a c t e r i s t i c of the deep  zone  (100-200 m) show a slow i n c r e a s e i n temperature' and a slow  decrease i n s a l i n i t y  as f r e s h water and h e a t s l o w l y mix down-  ward ( G i l m a r t i n , 1962).  These two  trends are v i s i b l e i n F i g s .  9 and 10 as a g r a d u a l deepening of i s o h a l i n e s and isotherms from August  to December 1968 Periodically  the waters  are d i s t u r b e d by i n t r u s i o n s .  of the deep zone are r e l a t i v e l y  except f o r the above-mentioned An i n t r u s i o n 1969. 1960  1969.  these p a t t e r n s o f the d i s t r i b u t i o n o f  temperature and s a l i n i t y intrusions  and from March to September  Between stable  trends toward warming and  dilution.  took p l a c e d u r i n g the p e r i o d January-February  Other, s i m i l a r i n t r u s i o n s o c c u r r e d i n 1956-57, 1959,  and  ( G i l m a r t i n , 1962; Regan, 1968). I n t r u s i o n s i n t o I n d i a n Arm  always have o c c u r r e d i n  e a r l y s p r i n g when t h e r e i s low s t a b i l i t y  o f the water  column  broughtftabout by w i n t e r c o o l i n g and low r u n o f f ( G i l m a r t i n , I f the a i r temperature i s l e s s  1962).  than 0 °C f o r any l e n g t h of time  streams are f r o z e n and thereby r u n o f f i s g r e a t l y reduced and the water  column may  become almost i s o p y c n a l .  v e r t i c a l mixing i s f a c i l i t a t e d in  and a r e l a t i v e l y  the o v e r a l l d e n s i t y of the water  ensue.  At such times r a p i d decrease  r e s i d e n t i n the i n l e t  may  I f , because o f v e r t i c a l m i x i n g , the d e n s i t y of the deep  water i n the i n l e t  f a l l s below t h a t of water p r e s e n t at  depth o u t s i d e the i n l e t  an i n t r u s i o n may  occur.  sill  -31-  Sub-freezing a i r temperatures were common during large parts of December 1968 and January 1969.  During the same period  strong (up to 60 kt) down-inlet winds occurred. V e r t i c a l mixing appears to have taken place, with the result, that i n January 1969 the water column was p r a c t i c a l l y isothermal and isohaline (Figs 9 and 10) and therefore nearly isopycnal. In February-March 1969 an intrusion of water from outside the i n l e t took place, displacing the resident water. The intruding water had a s a l i n i t y of approximately 27.2 and a temperature of 6.6 °C.  o/oo  The ultimate source of the  intruding water i s from the upper layers of the S t r a i t of Georgia. As a result of a lack of oceanographic data from outside the i n l e t , i t i s impossible to suggest a more s p e c i f i c o r i g i n .  -32IV.  THE EFFECTS OF STRESS FROM CHANGES IN TEMPERATURE AND SALINITY ON SPECIMENS FROM OCEANIC, OCEANIC-COASTAL, AND COASTAL WATERS.  Introduction Euphausia p a c i f i c a i s distributed widely i n waters which vary considerably i n t h e i r temperatures and s a l i n i t i e s (Regan, 1968; Mauchline and Fisher, 1969).  This d i s t r i b u t i o n ,  taken i n conjunction with the results of behavioural and s u r v i v a l experiments carried out by Regan (1968), suggests  that _E. p a c i f i c a  is tolerant of large changes i n the temperature and s a l i n i t y of i t s environment.  The same wide d i s t r i b u t i o n pattern could,  however, arise from the existence of a number of morphologically s i m i l a r populations of E_. p a c i f i c a which d i f f e r e d i n their tolerance to changes i n temperature and s a l i n i t y .  These  different populations could be considered as p h y s i o l o g i c a l races of E_. p a c i f i c a , such as are frequently found i n other species d i s t r i b u t e d over a wide range of environmental (Prosser, 1955; Vernberg, 1962).  conditions  This wide d i s t r i b u t i o n of  E_. p a c i f i c a , the p o s s i b i l i t y of p h y s i o l o g i c a l races, as w e l l as i t s tolerance toward laboratory handling (see above) afford an opportunity to examine interactions between the organism and i t s environment. Data are available on the reactions of several species of euphausiid to temperature changes (McWhinnie and Marciniak, 1964,  Teal and Carey, 1967).  Also available are s i m i l a r data  for populations of E_. p a c i f i c a from Saanich Inlet  (Paranjape,  -33-  1967) and from the P a c i f i c Ocean o f f Newport, Oregon (Small and Hebard, 1967).  However, no data are available on the effects  of s a l i n i t y changes on the metabolism of any euphausiid, other than Regan's (1968) data on s u r v i v a l .  Nor are theare data on  the e f f e c t of simultaneous v a r i a t i o n i n temperature and s a l i n i t y on either euphausiids or other zooplanktonic organisms, but i they have been presented f o r adults and larvae of several i species of benthic animals (Kinne, 1964, Brenko and Calabrese, 1969, Manzi, 19 70). The object of this part of the research program was to investigate the effects of stress from sources that could be measured and manipulated,  temperature and s a l i n i t y , on  three groups of specimens from three different areas i n which the temperatures and s a l i n i t i e s d i f f e r e d .  In addition to  observing the effect of stress from these sources, i t was desirable to determine whether there were any differences among the three groups i n the point at which stress from either, or both, sources became apparent. To this end, respiratory rates of individuals from each of the three locations were determined under a standard set of pairs of values for temperature and s a l i n i t y .  These  experiments provided information r e l a t i n g changes i n the animals' r e s p i r a t i o n rates to the changes i n stress resulting from variations i n temperature and s a l i n i t y .  The results also  serve to define roughly the non&lethal l i m i t s of temperature and s a l i n i t y that specimens from each of the locations could withstand.  In order to account for possible differences  -34r e s u l t i n g from changes i n seasonal states of acclimation to temperature, experiments were carried out on specimens captured  i n both summer and winter. The results of this part of the study indicate that  with E_. p a c i f i c a the action of stresses ensuing on changes i n temperature and s a l i n i t y may be additive, _i._e- the t o t a l e f f e c t from stress simultaneously  applied by changes i n both  temperature and s a l i n i t y may be greater than for either property separately.  This i s a r e f l e c t i o n of the fact that  the animals' reactions are to the sum of a l l stresses imposed on i t by the environment.  The results further show that  animals from the coastal population of E. p a c i f i c a possess a greater capacity to r e s i s t stress from temperature and s a l i n i t y -A  changes than animals from  cthecuoteanlcapopulation.  Materials and Methods. Because of l i m i t a t i o n s i n ship time and the possible problem of obtaining s u f f i c i e n t experimental animals, and e f f i c i e n t experimental design was required.  A three-factor  f a c t o r i a l experiment with f i v e replicates i n each c e l l was chosen as the basic design.  The three factors were: I.  Seasons - 2 levels (winter and summer); I I . Temperature - 3 levels (5°, 10°, 15° C); I I I . S a l i n i t y - 4 levels ( f u l l - s t r e n g t h sea water, 27, 24, 21 o/oo). were subjected  The data from these experiments  to analysis of variance i n order to test the  significance of the main effects of each of the factors as w e l l as the s i g n i f i c a n c e of the interactions between the effects of the factors. The f a c t o r i a l design s a c r i f i c e s some d e t a i l i n order to obtain an over-a-111 i n d i c a t i o n of the animals' reactions to  -35variations of temperature and s a l i n i t y .  Therefore, whenever  time and material allowed, this basic design was augmented by adding more levels of s a l i n i t y . approximates  Because the range 5° to 15° C  to the seasonal v a r i a t i o n i n temperature that the  animals might encounter, i t was thought that the three levels of temperature would give an adequate picture of the temperature responses of animals from the three locations. The specimens and water used i n the experiments were obtained by the procedures described i n Part II at stations Pac. 1, J.F. 9 and SAA 4. Results. A graphic presentation of the results of the experiment performed with animals from Saanich Inlet i s shown i n F i g . 11a. The data are plotted as r e s p i r a t i o n - s a l i n i t y (R-S) curves, data from June 1969 (summer animals) and February 1969 (winter animals) being plotted separately. It i s important to note that there i s a general, but small decrease i n r e s p i r a t i o n with decreased s a l i n i t y .  It  should also be observed that animals from Saanich Inlet could withstand a s a l i n i t y of 21 o/oo at 5°, 10° and 15° C i n summer and at 5° and 10°Gi±nwinter with no large reduction i n r e s p i r a t i o n rate. Fig. l i b shows R-S curves obtained using animals captured i n summer and winter at the mouth of Juan de Fuca Strait.  I t appears from these that there i s a s l i g h t immediate  reduction i n respiratory rate with the i n i t i a l d i l u t i o n from 34 o/oo and then no further reduction i n respiratory rate u n t i l some c r i t i c a l low s a l i n i t y i s reached at which respiration i s  -36-  Figure 11. (a-e)_ (facing) R e s p i r a t i o n - s a l i n i t y curves for Euphausia p a c i f i c a under various combinations of temperature and s a l i n i t y . a. Specimens from Saanich I n l e t , data collected i n February and June 1969. b. Specimens from Juan de Fuca S t r a i t , data collected i n November 1968 and July 1969. c. Specimens from the P a c i f i c Ocean, data collected i n February and June 1969.  SALINITY  %  SALINITY %  -37rapidly reduced.  Because the R-S curves are e s s e n t i a l l y  'flat'  between 34 and 24 o/oo i t appears that i n this range the animals' respiration rate i s independent of s a l i n i t y  changes.  Another important result i s that the lowest s a l i n i t y that animals from the mouth of Juan de Fuca S t r a i t could tolerate under a l l temperature conditions was 24 o/oo.  A s a l i n i t y of  21 o/oo proved f a t a l to a l l experimental animals acclimated at 15° C. Results.obtained using animals from the open ocean west of the Queen Charlotte Islands appear i n F i g . 11c.  It  should be noted that, f o r these animals too, respiration was independent of changes i n s a l i n i t y between 34 and 24 o/oo. There are indications (reduction i n respiratory rate) that for the winter animals 24 o/oo might be too d i l u t e at 15°C and perhaps also at 10°.  None of the animals could survive  a s a l i n i t y as low as 21 o/oo regardless of the temperature of acclimation, or the season. Results of analysis of variance performed on the data obtained with summer and winter animals from Saanich Inlet are shown i n Table 2.  S i g n i f i c a n t main effects are obtained for  temperature, s a l i n i t y , and seasons; of the possible interactions only the temperature x seasons interaction i s s i g n i f i c a n t . These results indicate that the respiration rate of Saanich animals i s influenced not only by the temperature and s a l i n i t y of the treatment, but also by seasonal differences i n the animals. The temperature x seasons i n t e r a c t i o n i s a r e f l e c t i o n of the d i f f e r i n g responses to changed temperature seen i n February  -38TABLE  2  Results of analysis of variance:  Reactions of Euphausia  p a c i f i c a from Saanich Inlet to changes i n temperature and s a l i n i t y , data from February 1969 and June 1969 combined.  Source of Variation Temperature  Sum of Squares 41.438  Mean Square 20.719  df  F-ratio  2  70.22**  Salinity  7.5904  3.7952  2  12.86**  Seasons  6.1429  6.1429  1  20.82**  Temperature x s a l i n i t y interaction  1.3094  0.32734  4  1.11  8.6112  2  29.18**  Temperature x seasons interaction  17.222  S a l i n i t y x seasons interaction  0.068188  0.034094  2  0.12  Temperature x s a l i n i t y x seasons interaction  2.22894  0.57234  4  1.94  Error  21.24525  0.29507  72  Total  98.398  Note:  89  The p r o b a b i l i t y of obtaining an F - r a t i o larger than the one  observed i s indicated by asterisks.  No asterisk  the p r o b a b i l i t y i s greater than 0.05;  indicates that  one asterisk  indicates  that the p r o b a b i l i t y of observing a larger F-ratio i s less than 0.05; 0.01.  two asterisks indicates that the probability i s less than  -39-  TABLE  3  Results of analysis of variance:  Reactions of Euphausia  p a c i f i c a from Juan de Fuca S t r a i t to changes i n temperature and s a l i n i t y , data from November 1968 and July 1969 combined.  Source of Variation Temperature Salinity  Sum of Squares 4.3301 17.413  Mean Square  df  F-ratio  2.1650  2  24.44**  4.3531  4  49.15**  Seasons  1.8062  1.8062  1  20.39**  Temperature x s a l i n i t y interaction  4.3672  0.54590  8  6.16**  Temperature x seasons interaction  0.065029  0.032514  2  0.37  S a l i n i t y x seasons interaction  1.8146  0.45365  4  5.12**  Temperature x s a l i n i t y x seasons i n t e r a c t i o n  1.0908  0.13635  8  1.54  Error  10.62939  0.08857  120  Total  41.516  149  -40-  TABLE Results of a n a l y s i s  of v a r i a n c e :  p a c i f i c a from the P a c i f i c and s a l i n i t y ,  4 Reactioncof Euphausia  Ocean t o changes i n temperature  d a t a from February 1969 and June 1969  combined.  Source of V a r i a t i o n  Sum o f Squares  Temperature  3.3785 55.359  Salinity  Mean Square 1.6892 18.453  df  F-ratio  2  8.92**  3  101.48**  Seasons  0.3224  0.3224  1  1.57  Temperature x s a l i n i t y interaction  1.8723  0.31205  6  1.57  Temperature x seasons interaction  0.19685  0.098427  0.48  S a l i n i t y x seasons interaction  1.584  0.51630  2.51  0.93924  0.15654  0.76  Temperature x s a l i n i t y seasons i n t e r a c t i o n  x  Error  19.7529  Total  83.370  0.20575  96 119  -41and June 1969  (see F i g . 11a).  At the same time, the non-  s i g n i f i c a n t i n t e r a c t i o n of temperature and s a l i n i t y suggests that the effects of these factors operated independently., Table 3 shows the results of analysis of variance carried out on the data obtained using animals from the mouth of Juan de Fuca S t r a i t .  Once again, s i g n i f i c a n t main effects  are obtained for temperature, s a l i n i t y , and seasons. s i g n i f i c a n c e of the temperature x s a l i n i t y interaction  The indicates  that the effects of temperature and s a l i n i t y are no longer independent.  Also the s a l i n i t y x seasons i n t e r a c t i o n suggests  that responses to s a l i n i t y per se changed s i g n i f i c a n t l y between November 1968 and July  1969.  Results of an analysis of variance performed on the data obtained using P a c i f i c Ocean animals (Table 4) indicate that only the main effects of temperature and s a l i n i t y are significant.  Neither the main e f f e c t of seasons, nor any of  the interactions are s i g n i f i c a n t .  Thus i t appears that the  animals' overallI respiratory rate did not change from February 1969 to June 1969 and that the effects of temperature and s a l i n i t y were independent. Discussion. The primary object of these three series of experiments was to investigate  the effects of s t r e s s , ensuing on changes  in temperature and/or s a l i n i t y , on the respiration of euphausiids from several locations.  The effects of stress a r i s i n g from  changes i n a single factor are best seen i n the results obtained with animals from the mouth of Juan de Fuca S t r a i t ( F i g . l i b ) .  -42-  Here, respiration tends to be only s l i g h t l y affected by changes i n the s a l i n i t y of the external medium u n t i l some c r i t i c a l , j L . j i . stressing, lower value of s a l i n i t y i s reached, whereupon the animals' respiration rate i s sharply reduced. Similar responses to changes i n s a l i n i t y have been reported for Calanus plumchrus from B.C. waters by Topping (1966) and for Calanus finnmarchicus from the Woods Hole region by Anraku (1964). ensues.  I f the stress i s prolonged or increased, death  The cause of the apparent upward s h i f t of the lower  c r i t i c a l s a l i n i t y between November 1968 and July 1969  (Fig. l i b )  i s unknown; i t appears i n the s t a t i s t i c a l analysis of the results as a s i g n i f i c a n t s a l i n i t y x season i n t e r a c t i o n (Table 3), which indicates that the response to lowered s a l i n i t y changed between November and July. The effects of reduced s a l i n i t y on the r e s p i r a t i o n of specimens caught i n the P a c i f i c Ocean ( F i g . 11c) show a s i m i l a r pattern of response.  That i s , the effect of stress  from reduced s a l i n i t y i s to reduce the respiration rate of E. p a c i f i c a . Because no sharp reduction i n respiratory rate was observed i n the results obtained with specimens from Saanich I n l e t , i t appears that the lower c r i t i c a l value of s a l i n i t y for these animals i s less than 21 o/oo. results obtained by Regan (1968).  This agrees with the  He found that, for animals  from Indian Arm, both s u r v i v a l and v e r t i c a l migration were affected by reduced s a l i n i t y ; the pattern of response was s i m i l a r to the effect of reduced s a l i n i t y on the respiration of animals from Juan de Fuca S t r a i t .  In b r i e f , Regan showed  -43-  that, there was a lower c r i t i c a l s a l i n i t y below which both s u r v i v a l and migration were severely affected.  Regan's (1968)  results show that the lower c r i t i c a l s a l i n i t y f o r migration and s u r v i v a l l i e s between 15 and 20 o/oo.  I t i s possible then  that animals from Saanich Inlet and Indian Arm may have s i m i l a r tolerances to reduced s a l i n i t y . The patterns .of response to reduced s a l i n i t y shown by E_. p a c i f i c a suggest that, some sort of i n t e r n a l mechanism exists to compensate for changes i n external s a l i n i t y , but that this mechanism breaks down at the lower c r i t i c a l s a l i n i t y . The very s l i g h t slope of the R-S  curves seems to indicate  that this mechanism requires a minimal expenditure of energy. If so the mechanism i s presumably  a passive one.  Possibly i t i s s i m i l a r to theoone reported by Shaw (1958) f o r muscle c e l l s of Carcinus maenas.  Shaw found that  the osmotic a c t i v i t y of the muscle c e l l s was  adjusted by  varying the i n t e r n a l concentration of amino acids and short-chain peptides. Winter oceanic animals did not show as large an increase i n respiratory rate i n f u l l - s t r e n g t h sea water for a r i s e i n temperature from 10° to 15° C as did the summer animals (Fig. 11c).  This, combined with a general opaque  appearance of the winter animals after the period of acclimation at 15° C indicated that they had been stressed.  Otherwise,  none of the specimens appeared to be stressed.byOiSerGiwhile i n f u l l - s t r e n g t h sea water.  -44-  Only the animals from Saanich Inlet appeared to change their respiratory response to increased temperature February (winter) to June (summer).  from  This change i s shown by  the much larger increase i n respiration between 10° and 15° C i n winter opposed to that i n summer.  The s i g n i f i c a n t  temperature  x seasons interaction i n the s t a t i s t i c a l analysis of the data (Table 2) points up the fact that the animals' responses to changed temperature are not the same i n summer and winter. Paranjape (1967) reports on the r e l a t i o n between r e s p i r a t i o n and temperature for summer E_. p a c i f i c a from Saanich Inlet.  In most instances the values f o r r e s p i r a t i o n  reported by Paranjape are smaller than those obtained i n the present study by a factor of two or more. During the course of this study tests were made on the effect of using as the experimental medium a r t i f i c i a l l y oxygenated water from the anoxic, deep water i n Saanich Inlet. The results of this experiment are not reported elsewhere i n this presentation, but they indicated that the re-oxygenated deep water could depress the respiratory rate of E.  pacifica  by a factor of two or more, a result closely resembling Paranjape's. Paranjape '(1967) does not say from what depth he collected the water used as an experimental medium.  I t appears,  however, as though the discrepancy between Paranjape's results and those of the present study could be explained i f he had inadvertently collected water which had originated i n the lower zone of Saanich Inlet.  -45-  Analysis of the results obtained with specimens collected at the mouth of Juan de Fuca S t r a i t (Table 3) indicates that the o v e r a l l ! respiratory rate increased between November 1968 and July 1969 ( s i g n i f i c a n t main e f f e c t for seasons).  No explanation f o r this increase i s offered.  At  the same time, s t a t i s t i c a l analysis of results obtained using animals from the P a c i f i c Ocean (Table 4) indicated that no seasonal changes occurred i n t h e i r respiratory rate. Small and Hebard (1967) found no seasonal change i n the respiratory rate of E_. p a c i f i c a from Oregon; the respiratory rates obtained i n the present study f o r oceanic animals are comparable with those reported by Small and Hebard.  They  are also comparable with those reported for E_. p a c i f i c a from the San Diego area by Lasker (1966). The R-S curves f o r animals from Juan de Fuca S t r a i t (Fig. l i b ) indicate that as the temperature increases the lower c r i t i c a l s a l i n i t y increases.  For winter animals the  lower c r i t i c a l s a l i n i t y l i e s below 21 o/oo f o r 5° and 10° C, but at 15° C i t l i e s between 24 o/oo and 21 o/oo.  In summer,  the lower c r i t i c a l s a l i n i t y l i e s between 24 o/oo and 21 o/oo at a l l three temperatures, but the degree to which respiration i s reduced increases as the temperature increases.  Both of  these sets of results appear to indicate that stresses r e s u l t i n g from changes i n temperature and s a l i n i t y are not independent i n their effect on E_. p a c i f i c a .  The s i g n i f i c a n t  temperature x s a l i n i t y i n t e r a c t i o n observed i n the s t a t i s t i c a l analysis of the above data (Table 3) i s another manifestation of the interdependence of the effects of temperature and salinity.  -46A s i m i l a r i n t e r a c t i o n between the effects of temperature and s a l i n i t y i s v i s i b l e i n the R-S curves f o r P a c i f i c Ocean winter animals (Fig. 11c); the summer animals give no i n d i c a t i o n of any interactions.  The results of s t a t i s t i c a l analysis  (Table 4) give no i n d i c a t i o n of a temperature x s a l i n i t y i n t e r a c t i o n , presumably because only one of the s i x R-S curves considered i n the analysis demonstrates an interaction. Data obtained f o r Saanich I n l e t animals ( F i g . 11a) indicate that the lower c r i t i c a l s a l i n i t y i s less than 21 o/oo at a l l three temperatures.  Therefore no i n t e r a c t i o n between  the effects of temperature and s a l i n i t y could be demonstrated. The results of analysis  of variance (Table 2) confirm the  independence of the effects of temperature and s a l i n i t y (temperature x s a l i n i t y interaction i s non-significant). I t appears, however, from the results of experiments using Juan de Fuca S t r a i t animals ( F i g . l i b ) that stresses r e s u l t i n g from variations i n temperature and s a l i n i t y interact i n t h e i r effects on IS. p a c i f i c a .  Thus , the combination of an  otherwise tolerable tempera tare; (15° C) with an equally tolerable s a l i n i t y (21 o/oo) may become i n t o l e r a b l e .  The  i n t e r a c t i o n appears to come into play when the l i m i t s of tolerance of temperature and s a l i n i t y (extreme values) are approached. In the data from the oceanic animals (Fig. 11c) there i s only a s l i g h t i n d i c a t i o n of a temperature x s a l i n i t y i n t e r a c t i o n (additive e f f e c t of stress from changes i n temperature and s a l i n i t y )  at 24 o/oo; a l l animals subjected to 21 o/oo died.  These results suggest that the range of s a l i n i t y over which  -47i n t e r a c t i o n occurs may be quite narrow. Regan (1968) using E_. p a c i f i c a from Indian Arm showed that there was an i n t e r a c t i o n between the effects of temperature and salinityoon both v e r t i c a l migration and s u r v i v a l .  Like-  wise McLeese (1956) who observed the effects of temperature, s a l i n i t y and dissolved oxygen content on the s u r v i v a l of Homarus americanus found that these three factors interacted strongly as l e t h a l values were approached.  Brenko and Calabrese (1969)  and Manzi (1970) studied the effects of various temperatures a l i n i t y combinations on adult and l a r v a l molluscs and found that stress from changes i n temperature and s a l i n i t y was additive at extreme values.  Costlow et al (1960) also obtained  a strong i n t e r a c t i o n between the effects of temperature and s a l i n i t y oil the s u r v i v a l of crab larvae.  Thus i t appears that  t h e i i n t e r a c t i o n of the effects of temperature and s a l i n i t y observed i n the course of this study i s a manifestation of a general property of organisms, jL.ja. that they react to the sum of a l l stresses imposed on them by the environment. In general the experimentally obtained respiratory rates (Figs. 11a, b, c) suggest that the animals from d i f f e r e n t locations have d i f f e r i n g tolerances to changes i n the temperature and s a l i n i t y of t h e i r environment.  That i s , animals from the  P a c i f i c Ocean were more stressed by 'changes i n temperature and s a l i n i t y than the animals from the mouth of Juan de Fuca S t r a i t , which, i n turn, were more stressed by the same changes than animals from Saanich Inlet.  -48It i s possible that the intermediate tolerances of the specimens from Juan de Fuca S t r a i t might be a result of employing a mixture of oceanic and coastal animals as experimental subjects.  I f this were so i t could be expected that s i z e of  the residual mean square i n the analysis of the data from Juan de Fuca S t r a i t would be increased over that of the analyses f o r the data from- the oceanic animals or the Saanich Inlet animals as a r e s u l t of the inhomogeneous reactions of the experimental material.  A comparison of error mean squares (Tables 2, 3, 4)  shows that there i s no i n d i c a t i o n that the animals from Juan de Fuca S t r a i t were less homogeneous i n their reactions to experimental conditions than those from the P a c i f i c Ocean or Saanich Inlet.  Therefore, they may be presumed to be from a  homogeneous population of _E. p a c i f i c a . In sum, therefore, these three homogeneous groups of _E. p a c i f i c a show large differences i n t h e i r resistance to experimental changes i n temperature and s a l i n i t y .  These differences  i n reactions to temperature and s a l i n i t y may represent a progressive extention of the absolute l i m i t s of tolerance to changes i n temperature and s a l i n i t y as a result of genetic adaptation to changed environmental conditions.  On the other hand, the  observed extention of the tolerable ranges of temperature and s a l i n i t y may r e f l e c t a c c l i m i t i z a t i o n of specimens to the warmer, more d i l u t e , coastal environment.  The experiments required to  determine which of the two alternatives referred to above i s correct were beyond the scope of this investigation. the differences between these three groups of E.  I f , however,  p a c i f i c a can  be shown to have a basis i n genetic change, then the groups could j u s t i f i a b l y be termed p h y s i o l o g i c a l races.  -49V.  THE EFFECT OF SEVERAL NATURAL SEA WATERS ON TOLERANCE TO TEMPERATURE AND  SALINITY VARIATIONS.  Introduction. Wilson and Armstrong (1952, 1954,  1958,  1961)  have  shown that some natural sea waters are more favorable for the development of echinoderm larvae than others.  Regan (1968)  found also that some sea waters from the l o c a l , B r i t i s h Columbia, area were more conducive to the s u r v i v a l of E_. p a c i f i c a than others.  These observations,  and others, lead to the hypothesis  that some sea waters can exert a deleterious e f f e c t , or s t r e s s , on some species while others might exert a neutral, or even a b e n e f i c i a l e f f e c t on the same species. suggests, moreover, that zooplanktonic  The above hypothesis  organisms can be  limited i n t h e i r d i s t r i b u t i o n to water bodies which have a neutral or b e n e f i c i a l e f f e c t on them as has been proposed by Bary (1963d).  This concept of 'water body control! of a species'  d i s t r i b u t i o n i s basic to the concept-of indicator species. The object of this portion of the experimental program was  to see whether any differences i n 'other' water properties  could affect, adversely or otherwise, the metabolism of adult E_. p a c i f i c a , i . e . to investigate the e f f e c t s on the animals of stress from undetermined and therefore non-measurfah'lee properties of sea water. The hypothesis was  that i f there  werea-anyvldeleteriidus  effects on the animals' metabolism as a result of differences i n 'other' properties, the i n t e r a c t i o n of stresses r e s u l t i n g from changes i n temperature and s a l i n i t y would be affected.  The  -50interdependence of the effects of stresses resulting from changes i n temperature, s a l i n i t y and oxygen concentration has been demonstrated by McLeese (1956) using Homarus americanus, and by Haefner (1970) using Crangon septemspinosa.  A similar  interdependence of the e f f e c t s , but of temperature, s a l i n i t y and toxic substances, has been demonstrated by Alderdice (1963) for young salmon; Wohlschlag and Cameron (1967) demonstrated a deleterious e f f e c t on the respiration-temperature relations of p i n f i s h resulting from the presence of low concentrations of petrochemical wastes. B a s i c a l l y the experimental design was  to subject the  animals to sublethal combinations of temperature and s a l i n i t y , i n media made from sea waters of different origins.  I t was  expected that i f the animals were stressed by differences i n 'other' properties between sea waters, there would be an i n t e r a c t i o n between their responses to extremes of temperature and s a l i n i t y and the source of the sea water used to make up the media. The results of these experiments indicate that the source of the experimental medium can have a s i g n i f i c a n t effect on the amount of stress the experimental animals can support.  The  results also indicate that, when tested i n a standard set of conditions, the animals' respiratory response to a series of sea waters may provide an index of the comparative amount of stress an animal l i v i n g i n each of them can support.  -51Materials and Methods. The experimental procedure was a standard three-factor f a c t o r i a l experiment with f i v e replicates i n each c e l l . of  One  the advantages of this design i s that the results lend them-  selves to analysis of variance.  In a l l , three experiments were  performed. The f i r s t of the three factors considered was temperature of which there were two or three levels depending on the p a r t i c u l a r experiment.  A l l experiments included 10° which was  regarded as non-stressful and 15° C which was considered to be moderately s t r e s s f u l .  The August  1969  experiment included  measurements made at 20° C which was highly s t r e s s f u l and appeared to be near the animals' upper l e t h a l l i m i t . S a l i n i t y was the second factor. were employed.  Two or three levels  Each of the experiments included measurements  made i n f u l l - s t r e n g t h sea water and i n sea water diluted to 21 o/oo. but of  In July  1969  measurements were obtained at 18 o/oo,  18 o/oo proved to be below the l e v e l of tolerance for most the specimens. The effects of changes i n 'other' water properties were  included at four levels i n a l l experiments, and at an additional l e v e l i n July  1969. The four standard levels corresponded to  water collected at two depths at each of two locations, one i n the S t r a i t of Georgia and the other i n Indian Arm (Fig.  3). The  shallower depth was the depth having the greatest concentration of  the euphausiid population, as determined by s t r a t i f i e d plankton  tows, and the other was a depth close to the bottom at each location.  -52-  A series of three experiments was carried out i n May, July, and August 1969.  None of the experiments was  precisely  the same because of progressive changes i n the detailed design, but those of July and August included the same set of treatments as used i n the May  experiment.  In May the experimental animals were collected at the surface at night at station G.S.-l (see Part II for the c o l l e c t i n g and handling techniques). were used, 10° and 15° C.  Two levels of temperature  Particulars of the experimental  waters used are shown i n Table 5.  Undiluted (full-strength) sea  water and water diluted to 21 o/oo with Barnstead-distilled water were the two levels of s a l i n i t y .  The experimental  animals were acclimated f o r 12 hours to each treatment and then t h e i r r e s p i r a t i o n was measured (see Part I I ) . Results of the May experiment suggested that perhaps the experimental animals had not been s u f f i c i e n t l y stressed to show adequately the effects of differences i n water properties. Therefore, the July experiment included a lower l e v e l of s a l i n i t y , 18 o/oo, to provide greater stress. temperatures used i n May,  The same two  10° and 15° C, were employed.  From the results of the July experiment i t appeared that 18 o/oo was below the l e t h a l l i m i t f o r most animals.  Thus, i t  appeared that the lower c r i t i c a l s a l i n i t y was quite sharply defined and i t was decided to increase the stress from temperature. In the August experiment i n addition to 10° and 15° C a t h i r d temperature, 20° C was included.  Only two s a l i n i t i e s ,  strength sea water and 21 o/oo, were used.  full-  -53TABLE  5  • The depth of c o l l e c t i o n and the s a l i n i t y of sea-water samples from Indian Arm and the S t r a i t of Georgia used i n the experiments carried out i n May, July and August 1969.  Ui  Geographic Area Indian Arm  upper water depth  \~ Georgia S t r a i t  lower water  upper water  lower water  So/oo  depth  So/oo  depth  Sjo/oo  depth  So/oo  27.04  200  27.18  100  29.91  350  30.80  26.87  200  27.14  75  29.73  350  30.96  26.78  200  27.12  75  29.88  350  30.96  May 75 July 75 Augus t 75  The water from Juan de Fuca S t r a i t which was used i n July was collected from a depth of 250 m and had a s a l i n i t y of 33.80 o/oo.  -54Statis t i c a l Analysis. Ordinarily seven animals were acclimated i n each b o t t l e . This allowed for accidental loss during handling.  In  s t r e s s f u l treatments mortality during acclimation was  nonrare.  During acclimation to more s t r e s s f u l treatments mortality became more frequent. The purpose of the experiments was  to determine the  animals' reactions to the experimental conditions. i t was  Therefore,  f e l t that some account should be taken of the mortality,  presumed to have resulted from stress imposed by the treatment; otherwise information would be l o s t .  Because the respiratory  rates of stressed E_. p a c i f i c a generally decreased with increased stress i n experiments where no mortality occurred,it was  felt  that entry of zero values for the r e s p i r a t i o n of those animals which died before measurement was  not unreasonable/  At the  same time i t should be kept i n mind that there i s a q u a l i t a t i v e difference betwen a l i v e and a dead animal.  I t i s possible that  this q u a l i t a t i v e difference might introduce a non-orthogonal component into the analysis.  However, because highly stressed,  but a l i v e , specimens y i e l d low respiratory rates, the e f f e c t of using zero values for dead animals i s not considered  to be  serious. The  technique that evolved was  that when f i v e or more  of the seven o r i g i n a l animals survived to have t h e i r r e s p i r a t i o n rates determined, f i v e animals were tested and respiration rates entered i n t o the analysis.  their  When less than  f i v e animals survived the respiratory rates of the survivors were included, along with zero values for the dead animals. The s t a t i s t i c a l analysis of the results was  carried out  -55using multifactor analysis of variance.  Replication was  treated as a factor to simplify the preparation for analysis.  of the data  A l l possible i n t e r a c t i o n terms were computed.  The n u l l hypothesis was that none of the factors had any e f f e c t on the respiration rates of the experimental animals. In the analysis of the results of the July experiment a s i g n i f i c a n t main e f f e c t for r e p l i c a t i o n (Table U) was obtained as w e l l as a s i g n i f i c a n t s a l i n i t y x r e p l i c a t i o n interaction. In this instance  r e p l i c a t i o n i s purely nominal and refers to the  order i n which the data were punched on computer cards.  This  r e s u l t obtains because most bf the animals i n the treatments involving  I80/00  s a l i n i t y , as w e l l as many i n 21  0/00,  died.  Replication was purely nominal, and therefore when the data were punched on the cards no e f f o r t was made to randomize the order of the zero entries corresponding to the r e s p i r a t i o n rates of the dead animals.  I t was f e l t that this non-random  d i s t r i b u t i o n of zero values would not a f f e c t the accuracy of the analysis.  For the July analysis the non-significant  i n t e r a c t i o n sums of squares and degrees of freedom for r e p l i c a t i o n effects have been pooled with the error sum of squares.  In the analysis f o r May and August no s i g n i f i c a n t  effects were observed for r e p l i c a t i o n , so a l l sums of squares and degrees of freedom for r e p l i c a t i o n , have been pooled with the error term. Results. Assuming there was no i n t e r a c t i o n between the source of the water used to make up the experimental media ('water properties') and  the e f f e c t s of temperature and s a l i n i t y , the expected r e s u l t of  -56-  the experiments, i f there were s i g n i f i c a n t effects of water properties, would be eight p a r a l l e l R-S curves (four waters at two temperatures). two p a r a l l e l R-S  I f there were no effect of water properties,  curves would be expected.  An i n t e r a c t i o n  between factors would cause the R-S curves to be non-parallel. The results of the May experiment ( F i g . 12a) are represented by eight non-parallel R-S curves, thus i n d i c a t i n g that not only is there an e f f e c t of 'water properties' on respiration rate per se, but that there i s also an interaction of these effects with the effects of temperature and s a l i n i t y . The s t a t i s t i c a l analysis of the results of the May experiment (Table 6) shows that, while the main effects of both temperature and water properties are s i g n i f i c a n t , the main e f f e c t of s a l i n i t y i s not s i g n i f i c a n t .  This would appear to  indicate that s a l i n i t y per se had no e f f e c t on the euphausiids' respiration.  However, there i s a large water properties x  s a l i n i t y i n t e r a c t i o n which indicates that the e f f e c t of variations in s a l i n i t y depends upon the type of water the animal i s i n . The temperature x s a l i n i t y interaction i s non-significant which suggests that the main effects of temperature and s a l i n i t y are independent and that the higher temperature and lowered s a l i n i t y used i n this experiment were not s u f f i c i e n t l y s t r e s s f u l , even i n combination, to affect.the animals.  The temperature x  water properties i n t e r a c t i o n i s s i g n i f i c a n t which suggests that the e f f e c t of temperature changes with the source of water used as an experimental medium.  There i s , however, l i t t l e  i n d i c a t i o n that any of the waters has p a r t i c u l a r l y deleterious or b e n e f i c i a l effects on the animals.  -57-  Figure 12. (a-c) (facing) R e s p i r a t i o n - s a l i n i t y curves for Euphausia p a c i f i c a from the S t r a i t of Georgia while i n media made from 4 sea waters collected at d i f f e r i n g depths and locations. a. Data from the experiment performed i n May 1969. b. Data from the experiment performed i n July 1969. c. Data from the experiment performed i n August 1969.  -58TABLE  6  Results of analysis of variance:  Reaction of Euphausia  p a c i f i c a from the S t r a i t of Georgia to changes i n temperature, s a l i n i t y and 'other' water properties; data from the experiment performed i n May 1969.  Source of Variation  Sum of Squares  Mean Square  df  F-ratio  Temperature  5.6743  5.6743  1  8.809**  Salinity  1.3225  1.3225  1  2.05  Water properties  6.3539  2.1180  3  3.288*  Temperature x s a l i n i t y interaction  0.02178  0.02178  1  0.0 34':  Temperature x water property i n t e r a c t i o n  5.7477  1.9159  3  2.974*  S a l i n i t y x water property i n t e r a c t i o n  9.9497  3.3166  3  5.149*  0.6441  67  Error  43.157  Total  72.227  79  - 59:  The graphic representation of the results of the July experiment ( F i g . 12b) shows two 'families' of R-S curves, designated 'a' and 'b'.  R-S curves i n the 'a' group  demonstrate  less reduction i n respiration between f u l l - s t r e n g t h sea water and 21 o/oo than those i n the 'b' group.  Presumably these  d i f f e r e n t responses are mediated by differences i n water properties. The 'a' group of R-S curves includes measurements made at 10° and 15° C i n both shallow and deep waters from Indian Arm and the 10° C measurements i n S t r a i t of Georgia upper water.  The  'b' group of curves includes both the 10° and 15° C measurements i n S t r a i t of Georgia lower water and the 15° C measurements i n S t r a i t of Georgia upper water.  I t should be noted that  respiratory rates determined at 10° C i n Indian Arm waters are higher than those i n Georgia S t r a i t waters. The s t a t i s t i c a l analysis of the results of the July experiment (Table 7) shows that the main effect of temperature i s non-significant; the main effects of s a l i n i t y and water properties are s i g n i f i c a n t .  There i s a s i g n i f i c a n t  temperature  i x s a l i n i t y i n t e r a c t i o n suggesting that the effects of temperature and s a l i n i t y are no longer independent, presumably as a result of adding a lower l e v e l of s a l i n i t y (18 o/oo). The lack of-a s i g n i f i c a n t temperature x water properties i n t e r a c t i o n (Table 7) indicates that the effects of temperature on the animals' metabolism may not be influenced by the source of the water used as the experimental medium.  This s i t u a t i o n  probably results from the fact that any stressing e f f e c t of water properties on these animals seems to be small.  Thus,  -60TABLE  7  Results of analysis of variance:  Reactions of Euphausia  p a c i f i c a from the S t r a i t of Georgia to changes i n temperature, s a l i n i t y and 'other' water properties, data from the experiment performed i n July 1969.  Source of Variation Temperature Salinity  Sum of Squares 0.54397 131.07  Mean Square 0.54397 65.533  df  F-ratio  1  1.83  2  221.32**  Water properties  9.0340  2.2585  4  7.62**  Temperature x s a l i n i t y interaction  7.9987  3.9994  2  13.51**  Temperature x water property i n t e r a c t i o n  2.3188  0.5797  4  1.96  S a l i n i t y x water property i n t e r a c t i o n  5.2293  0.65366  8  2.21*  Temperature x s a l i n i t y x water property i n t e r a c t i o n  5.2443  0.65553  8  2.21*  Replication  4.1901  1.0475  4  3.53**  Salinity x replication  5.9650  0.74563  8  2.51**  0.29610  108  Error Total  31.979 203.57  -61-  since the higher of the two temperatures used was not stressing to these p a r t i c u l a r animals, the two effects operated independently. The s i g n i f i c a n t s a l i n i t y x water properties interaction probably i s a r e f l e c t i o n of the additive nature of stress from low s a l i n i t y and from changes i n water properties.  The  same causes likewise probably act to produce the s i g n i f i c a n t temperature x s a l i n i t y x water property i n t e r a c t i o n . The causes of the s i g n i f i c a n t r e p l i c a t i o n effect have been described i n the section on s t a t i s t i c a l analysis and need not be discussed here. The graphic presentation of the results of the August experiment ( F i g . 12c) shows a strong interaction between the effects of temperature and 'water properties' i n that a l l specimens i n the shallow and deep water from Indian Arm died at 20° C regardless of the s a l i n i t y .  At the same time a l l those  i n both upper and lower water from the S t r a i t of Georgia at f u l l - s t r e n g t h and some of those i n G.S. upper water at 21 o/oo, lived.  There are no c l e a r l y defined groupsoof water property  interactions such as were present i n July.  On the whole, the  respiration rates i n August i n Indian Arm waters have decreased.while those i n waters from the S t r a i t of Georgia have increased from those observed i n July.  In August there i s some i n d i c a t i o n , i n  that the R-S curves obtained at 10° and 15° C are nearly p a r a l l e l , that S t r a i t of Georgia lower water i s the one i n which the experimental animals exhibit the most 'normal' responses. This i s the same water i n which the highest respiratory rate was obtained when measurements made at 10° C i n f u l l strength sea water are compared ( F i g . 12c).  -62-  R e s u l t s o f the s t a t i s t i c a l a n a l y s i s o f the d a t a from the August experiment a r e shown i n T a b l e 8.  They a r e s i m i l a r  to the r e s u l t s o f the J u l y experiment except that the main e f f e c t o f temperature i s s i g n i f i c a n t , presumably because h i g h e r l e v e l o f temperature  a  (20° C) has been i n c l u d e d . A l l  i n t e r a c t i o n s a r e s i g n i f i c a n t which  i n d i c a t e s a l a r g e degree of  i n t e r d e p e n d e n c e i n t h e e f f e c t s o f temperature, s a l i n i t y , and water  properties.  Discussion. The h y p o t h e s i s used i n the f o r m u l a t i o n of the three experiments was t h a t any d i f f e r e n c e s i n vitifae.v& p r o p e r t i e s 1  of  s e a waters a c t i n g d e l e t e r i o u s l y on t h e e x p e r i m e n t a l a n i m a l s , would add t o the s t r e s s i n g e f f e c t s of lowered s a l i n i t y temperature.  and e l e v a t e d  That i s , t h e r e s h o u l d be an i n t e r a c t i o n between  s t r e s s e s r e s u l t i n g from reduced s a l i n i t y  and e l e v a t e d  temperature  and s t r e s s e s r e s u l t i n g from d i f f e r e n c e s i n 'other' p r o p e r t i e s between s e a w a t e r s . that stress  T h i s h y p o t h e s i s was based on the assumption  from a l l sources would be a d d i t i v e i n i t s e f f e c t on  the metabolism o f E. shown w i t h s t r e s s  p a c i f i c a , i n the same f a s h i o n as has been  from changes  i n temperature and s a l i n i t y i n  P a r t IV. The s i g n i f i c a n t main e f f e c t s o f water p r o p e r t i e s  (Tables,  6, 7, and 8) i n d i c a t e t h a t s e a water from d i v e r s e s o u r c e s can affect  the r e s p i r a t i o n r a t e o f E. p a c i f i c a .  t h r e e experiments show s i g n i f i c a n t  The r e s u l t s o f a l l  i n t e r a c t i o n s between water  p r o p e r t i e s and temperature and/or s a l i n i t y e f f e c t s animals' r e s p i r a t i o n .  T h i s i n d i c a t e s t h a t whatever p r o p e r t y o f  s e a water i t i s that i s b e i n g r e f e r r e d can a f f e c t  on t h e  to as 'water p r o p e r t i e s ' ,  the e x p e r i m e n t a l a n i m a l s ' a b i l i t y  to w i t h s t a n d  TABLE  8  Results of analysis of variance:  Reactions of Euphausia  p a c i f i c a from the S t r a i t of Georgia to changes i n temperature, s a l i n i t y and 'other' water properties, data from the experiment performed i n August 1969.  Source of Variation  Sum of Squares  Mean Square  df  F-ratio  Temperature  50.650  25.325  2  51.75**  Salinity  12.006  12.006  1  24.54**  Water properties  11.870  3.9565  3  8.07**  4.6641  2  9.52**  Temperature x s a l i n i t y interaction Temperature x water property i n t e r a c t i o n S a l i n i t y x water property i n t e r a c t i o n  9.3282  15.316 4.6595  2.5526  5.21**  1.5532  3.16*-'6.20**  Temperature x s a l i n i t y x water property i n t e r a c t i o n  18.199  3.0332  Error  46.9642  0.4892  Total  168.99  1  96 119  -64stress from other sources. There remains, however, the question of what is_ being referred to as water property e f f e c t s .  I t i s possible that  differences i n the i n i t i a l s a l i n i t i e s of the full-strength sea waters used i n the three experiments (Table 5) might have affected the results.  A l l of these s a l i n i t i e s , however, lay  w e l l within the ' f l a t ' part of the R-S curves obtained f o r euphausiids from Saanich Inlet and from Juan de Fuca S t r a i t . (Figs. 11a, b ) .  Therefore i t appears l i k e l y that differences  i n i n i t i a l s a l i n i t y probably do not affect the results.  Evidence  supporting this i s found i n the fact that when the effects of waters from Indian Arm and the S t r a i t of Georgia changed i n a complementary  fashion between July and August (Figs. 12b, c ) ,  the s a l i n i t i e s of the four waters hardly changed at a l l between the two months.  Both of these pieces of evidence appear to  indicate that the i n i t i a l s a l i n i t i e s are not appreciably affecting the results and thus that the source of the water property effects w i l l have to be sought elsewhere. Possibly the d i l u t i o n of the sea waters with water d i s t i l l e d i n a metal (tin) s t i l l might have had some e f f e c t on the animals' respiration other than that of reduced osmotic pressure as a r e s u l t of contamination.  Gostlow (1969, p. 306)  has suggested that there was an appreciable difference i n the time to the f i r s t zoeal moult f o r crab larvae maintained i n Instant Ocean, medium made up with tap water, metal d i s t i l l e d water, and glass d i s t i l l e d water.  These results indicate that  contamination i n the d i s t i l l e d water used i n this study might  -65have been a source of error.  On the other hand, i n the same  report Provasoli (p. 306) states that any t i n residue i n Bams tead-dis t i l l e d water i s not deleterious for culturing experiments. Presumably, i f traces of tine were harmful, the water requiring the greatest d i l u t i o n to reach 21 o/oo would consistently exert the most deleterious e f f e c t s . the results of the present study.  This i s not the case i n  S t r a i t of Georgia upper and  lower water require a greater d i l u t i o n to reach 21 o/oo than either Indian Arm upper or lower water; yet? ?they are not consistently the l e a s t b e n e f i c i a l waters.  On the contrary, i n  August the S t r a i t of Georgia waters were by far the most b e n e f i c i a l . : Therefore,  i t seems l i k e l y , that the varying  amounts of d i s t i l l e d water introduced no systematic  error i n  the animals' r e s p i r a t i o n and thus that the d i s t i l l e d water used was not deleterious i n i t s effects on the animals. I t i s also possible that the combination of 20° C and the s a l i n i t i e s of the two waters from Indian Arm (Table 5) might be l e t h a l to the animals as a r e s u l t of the i n t e r a c t i o n of temperature and s a l i n i t y e f f e c t s alone with no added e f f e c t of 'water properties'.  The fact that some animals survived at a  s a l i n i t y of 21-o/oo i n S t r a i t of Georgia upper water, however, indicates that, i f there were no e f f e c t from 'water properties', some animals should have survived i n f u l l - s t r e n g t h sea water from Indian Arm because i t had a s a l i n i t y higher than 21 o/oo (Table 5). I t i s also u n l i k e l y that any of the laboratory procedures could have biased the results i n favor of any of the waters, because a l l waters were treated as nearly a l i k e as possible i n  -66-  both c o l l e c t i n g and laboratory techniques. Therefore i t seems that whatever i s causing the effects c l a s s f i e d under general heading of 'water properties' i s an actual property or properties of the water, d i s t i n c t from i t s s a l i n i t y and not an a r t i f a c t of either c o l l e c t i n g or laboratory technique.  Thus, the interaction of effects of  'water properties' with stress resulting from changes i n temperature and s a l i n i t y are i n d i c a t i v e of changes i n the s u i t a b i l i t y of d i f f e r e n t sea waters as media for £-. p a c i f i c a . These results are s i m i l a r inppattern to those reported by Wilson and Armstrong (1952, 1954, 1958, 1961) who  investigated  the s u i t a b i l i t y of various natural sea waters as culture media for echinoderm larvae.  They are also s i m i l a r to the results  obtained by Regan (1968) i n h i s series of experiments on the a b i l i t y of E_. p a c i f i c a from B.C. coastal waters to survive i n waters collected from various l o c a l areas.  Wilson and Armstrong,  and Regan, found that there were appreciable differences i n the s u r v i v a l rates of t h e i r experimental animals i n sea waters from d i f f e r e n t geographic areas; these differences were interpreted as stemming from differences i n 'other' properties of sea water. The graphical respresentation of the results of the July experiment (Fig. 12b), indicates that some of the waters may be more b e n e f i c i a l i n t h e i r effects on the animals than others, in that the reduction i n respiration between f u l l - s t r e n g t h sea water and 21 o/oo was l e s s .  The Indian Armuupper and lower  waters allow the experimental animals to withstand more stress from temperature and s a l i n i t y changes than either water from  -67the S t r a i t of Georgia.  I t i s also clear that S t r a i t of Georgia  upper water i s superior to the lower water.  This i s approximately  the order i n which the waters would appear i f ranked from highest to lowest on the basis of the respiration i n them of E_. p a c i f i c a i n full-strength sea water at 10° C. Results of the August experiment (Fig. 1 2 c ) again show that one group of waters i s more b e n e f i c i a l i n i t s effects on the animals than another.  In this instance the two waters  from S t r a i t of Georgia are the most b e n e f i c i a l , as shown by the fact that i t i s not u n t i l 20° C that the effect of 21 o/oo becomes greatly deleterious.  In Indian Arm upper water 2 1 o/oo  reduces the animals' respiration rate at a l l three temperatures. Indian Arm lower water appears to be s l i g h t l y more b e n e f i c i a l i n i t s effects but no animals were able to survive at 20° C even i n f u l l - s t r e n g t h sea water.  Again, there i s an i n d i c a t i o n that  the amount of stress that an animal can stand i n a given water may be indicated by the r e l a t i v e respiration rates i n f u l l strength sea water at 10° C. The results of a l l three experiments show that sea waters from various sources can affect the r e s p i r a t i o n rate of _E. p a c i f i c a .  For reasons given above i t appears unlikely  that differences i n the i n s i t u s a l i n i t y of the sea waters or the handling a f t e r c o l l e c t i o n could have caused the observed differences.  The implication i s , therefore, that the factors  causing the differences i n respiratory rates are the i n t r i n s i c , 'other' properties of the sea waters used i n the experiments^ not their i n s i t u temperature and/or s a l i n i t y .  -69VI.  ANNUAL CHANGES IN THE REACTIONS OF TWO  COASTAL POPULATIONS  OF EUPHAUSIA PACIFICA TO NATURAL SEA WATERS. Introduction. Lewis and Ramnarine (1969) present evidence that sea water from a constant depth at one station varies from month to month i n i t s s u i t a b i l i t y as a culture medium f o r copepod larvae. Further they show that sea water, which may be poor as a culture medium, can be improved by adding small amounts of chelated trace elements, i n p a r t i c u l a r cobalt and zinc (Lewis, 1967). Lewis and Ramnarine i n f e r from these findings that at some times of the year the natural sea water they collected was  deficient  i n cobalt and/or zinc, or i n chelation. Further evidence (Lewis, MS i n prep.) indicates that seasonal variations i n the e f f e c t of enrichment of sea water are related to changes i n physical oceanographic processes. The greatest influence on these processes appears to be the amount of runoff from the Fraser River and the upwelling o f f the mouth of Juan de Fuca S t r a i t (see Part III of this report). Regan (1968) carried out a series of experiments using E_. p a c i f i c a from Indian Arm i n which the s u r v i v a l of specimens i n sea waters from several l o c a l areas was compared.  The  results of these experiments were reported as an 'order of preference', the most highly preferred water being that having the highest s u r v i v a l rate.  Water from Indian Arm ('home water')  was always most preferred, but after that the order changed from one experiment to another.  The s u r v i v a l rate i n 'home water'  also varied from experiment to experiment.  Regan suggested  that these changes i n order of preference were related to  -70-  changes  i n the hydrography o f the a r e a s . Regan proposed the h y p o t h e s i s t h a t specimens  o f _E.  p a c i f i c a i n d i g e n o u s to I n d i a n Arm had adapted t o the 'other' p r o p e r t i e s o f the water a t i n t e r m e d i a t e depths i n such a way to r e a c t a g a i n s t the 'other' p r o p e r t i e s of waters another a r e a . against  as  from  He a l s o suggested t h a t r e a c t i o n s toward and  'other' p r o p e r t i e s a f f e c t e d the d i s t r i b u t i o n of _E.  p a c i f i c a i n I n d i a n Arm.  Thus, the absence of specimens  i n the  deep wate r s r e s u l t e d from "... an adverse r e a c t i o n of specimens water"  towards  the 'unique ('other') p r o p e r t i e s ' of deep  (Regan, 1968, p. 157). The r e s u l t s  o b t a i n e d by Lewis and Ramnarine (1969)  a n d b y Regan (1968) i n d i c a t e t h a t the d i s t r i b u t i o n of water p r o p e r t i e s which might a f f e c t the s u r v i v a l of E_. p a c i f i c a o r copepod  l a r v a e v a r i e s w i t h the g e o g r a p h i c a r e a and w i t h time.  Regan's r e s u l t s a l s o i n d i c a t e t h a t E_. p a c i f i c a from I n d i a n Arm may  have become adapted to the c o n d i t i o n s t h e r e ; h i s  o r d e r of p r e f e r e n c e i n d i c a t e s t h a t specimens  are s t r e s s e d by  b e i n g p l a c e d i n water from any o t h e r s o u r c e . I f specimens  o f E.  p a c i f i c a can adapt to the p e c u l i a r  w a t e r p r o p e r t i e s of one p a r t i c u l a r environment as i t appears the specimens  from I n d i a n Arm used by Regan may have done, i t may  be presumed t h a t they can adapt t o another.  I f so, i t i s  p o s s i b l e that t h e r e w i l l e x i s t a number of p o p u l a t i o n s , each o f which would r e a c t d i f f e r e n t l y i f p r e s e n t e d to one environment and i t s 'other' p r o p e r t i e s .  particular  -71-  The  r e s u l t s o f t h e p r e v i o u s p a r t o f t h i s s t u d y ( P a r t IV)  i n d i c a t e t h a t animals l i v i n g i n some s e a w a t e r s a r e a b l e t o s u p p o r t more s t r e s s from changes i n temperature and s a l i n i t y than those i n o t h e r s .  The r e s u l t s a l s o i n d i c a t e t h a t the  r e l a t i v e o r d e r o f t h e r e s p i r a t o r y r a t e s , from h i g h e s t  to lowest,  o b t a i n e d w i t h E. p a c i f i c a i n a s e r i e s o f s e a w a t e r s under standard conditions  c o u l d i n d i c a t e t h e r e l a t i v e amounts o f s t r e s s  from g r e a t e s t t o l e a s t t h a t c o u l d be w i t h s t o o d  by specimens i n  each o f these w a t e r s . The  object of t h i s p o r t i o n (Part VI) of the research  p r o j e c t i s t o s t u d y v a r i a t i o n s i n t h e d i s t r i b u t i o n o f 'other' properties.  I t was approached by u s i n g the r e s p i r a t i o n o f  specimens o f E_. p a c i f i c a as an i n d e x o f ' d e s i r a b i l i t y ' .  It  was e x p e c t e d t h a t the use o f specimens from two c o a s t a l l o c a t i o n s ( I n d i a n Arm, t h e S t r a i t o f G e o r g i a ) would g i v e an i n d i c a t i o n of whether s e p a r a t e p o p u l a t i o n s by t h e i r d i f f e r e n t r e a c t i o n s  o f _E. p a c i f i c a ,  characterized  to water p r o p e r t i e s , e x i s t . I t  was a l s o e x p e c t e d t h a t t h e r e s u l t s would i n d i c a t e whether t h e d i s t r i b u t i o n o f E_. p a c i f i c a i n I n d i a n Arm o r i n t h e S t r a i t o f G e o r g i a was a f f e c t e d by d i f f e r e n c e s i n 'other' The  properties.  r e s u l t s of t h i s study i n d i c a t e that.the  'desirability'  of s e a w a t e r c o l l e c t e d a t a g i v e n s t a t i o n and d e p t h , changes throughout t h e y e a r i n a s s o c i a t i o n w i t h changes i n o c e a n o g r a p h i c processes.  The, . r e s u l t s a l s o i n d i c a t e t h a t t h e two  populations  o f E. p a c i f i c a used had c h a r a c t e r i s t i c , b u t d i f f e r e n t , r e a c t i o n s t o the same s e a w a t e r s .  There was, however, no i n d i c a t i o n t h a t  'other' p r o p e r t i e s were e f f e c t i v e i n d e t e r m i n i n g t h e d i s t r i b u t i o n  -72-  of  E_. p a c i f i c a w i t h i n e i t h e r I n d i a n Arm  Georgia,  although  they may  p o p u l a t i o n s i n I n d i a n Arm  or the S t r a i t  of  be e f f e c t i v e i n m a i n t a i n i n g and  the S t r a i t of  separate  Georgia.  M a t e r i a l s and Methods. The firstly,  aim of t h i s p a r t of the study was  two-fold;  to examine e f f e c t s on specimens of E_. p a c i f i c a  of  v a r i a t i o n s i n water p r o p e r t i e s on a y e a r l y b a s i s i n r e l a t i o n hydrographic  c o n d i t i o n s , and s e c o n d l y ,  geographically separate populations differently The  experiment which was a standard  designed  the S t r a i t of G e o r g i a  and  I n d i a n Arm  these with  p a c i f i c a from ( G . S . - l , F i g . 3;  l e v e l s of the f i r s t  second f a c t o r , water p r o p e r t i e s , was  l e v e l s , namely an  to examine  Specimens of E.  I.A.-9, F i g . 3), comprised the two The  of E_. p a c i f i c a r e a c t  t h r e e - f a c t o r f a c t o r i a l design  f i v e r e p l i c a t e s i n each c e l l . areas,  to determine whether  to waters w i t h s i m i l a r p r o p e r t i e s .  q u e s t i o n s was  two  factor.  r e p r e s e n t e d by  four  'upper' water a t each of the two s t a t i o n s  c o l l e c t e d at the l e v e l of the g r e a t e s t c o n c e n t r a t i o n of e u p h a u s i i d p o p u l a t i o n , and  Table 9 g i v e s the depth  from which the- two waters were c o l l e c t e d i n I n d i a n Arm as t h e i r i n s i t u  the  a 'lower' water c o l l e c t e d from a  depth near the bottom at each s t a t i o n .  temperatures and s a l i n i t i e s .  as w e l l  T a b l e 10  gives  the same i n f o r m a t i o n f o r the two waters c o l l e c t e d i n the of  Georgia.  Time, the t h i r d f a c t o r , was  the 14 months between August 1968 are no o b s e r v a t i o n s for  to  f o r March 1969  a few months p r e c e d i n g August  r e p r e s e n t e d by  and September 1969. and 1968.  only p a r t i a l  Strait 13 o f  There observations  TABLE  9  Temperatures, s a l i n i t i e s , and depths from which the two waters used i n experiments were collected from Indian Arm  Month  Indian Arm Upper Water  Indian Arm Lower Water  z  T  S  z  T  S  125  8.34  26.574  200  8.35  26.678  75  10.28  26.031  200  8.34  26.644  October 1968  100  8.48  26.338  200  8.37  26.618  November 1968  100  8.73  26.351  200  8.36  26.607  December 1968  100  9.10  26.280  200  8.41  26.592  January 1969  100  8.06  26.464  200  7.04  26.446  February 1969  100  6.17  26.739  200  6.28  26.824  March 1969  100  6.51  27.136  200  6.57  27.204  A p r i l 1969  100  6.49  27.199  200  6.57  27.186  75  6.46  27.044  200  6.59  27.175  June 1969  100  6.53  27.091  200  6.58  27.171  July 1969  75  6.63  26.870  200  6.60  27.140  August 1969  75  6.85  26.717  200  6.58  27.121  September 1969  75  7.21  26.715  200  6.59  27.108  August 1968 September 1968  May 1969  TABLE 10 Temperatures, s a l i n i t i e s , and depths from which the two waters used i n experiments were collected i n the S t r a i t of Georgia  Month  S t r a i t of Georgia Upper Water  S t r a i t of Georgia Lower Water  z  T  S  z  T  S  August 1968  100  8.60  30 .221  350  8.70  30.926  September 1968  125  9.10  30 .544  350  8.88  31.107  October 1968  100  9.26  30 .341  350  9.04  31.118  November 1968  125  9.29  30 .570  350  8.98  31.138  December 1968  100  9.28  30 .295  350  9.05  31.066  75  8.28  29 .684  350  9.01  310014  February 1969  100  7.19  29 .850  350  9.00  31.028  March 1969  100  7.00  29 .925  350  9.02  30.950  A p r i l 1969  100  7.25  29 .776  350  8.90  30.852  May 1969  100  7.32  29 .910  350  8.62  30.799  June 1969  75  8.25  29 .665  350  8.47  30.770  July 1969  75  7.89  29 .728  350  8.58  30.756  August 1969  75  8.82  29 .710  350  8.'80  30.831  September 1969  75  9.37  30 .158  350  9.13  31.057  January 1969  75  The e f f e c t of  of water p r o p e r t i e s was  specimens i n each of the f o u r waters  outlined was  i n Part I I .  The  statistical  a s s e s s e d by measuring  at 10° C u s i n g the  respiration  techniques  a n a l y s i s o f the r e s u l t i n g  data  c a r r i e d out by means o f m u l t i f a c t o r a n a l y s i s of v a r i a n c e w i t h  t r e a t e d as a f a c t o r . squares and degrees The  replication  In r e p o r t i n g the r e s u l t s a l l r e p l i c a t i o n sums of of freedom have been pooled w i t h the e r r o r  r e s u l t s are r e p o r t e d as a n a l y s i s of v a r i a n c e t a b l e s  g r a p h i c a l l y i n F i g u r e s 13a and  term.  11 t o 18  and  13b.  Results. R e s u l t s of an-;analysis o f a l l d a t a o b t a i n e d over 13 months u s i n g animals  from both I n d i a n Arm  a r e shown i n Table 11. time  (months),  and  the S t r a i t o f Georgia  i n the f o u r waters  Of the t h r e e sources of v a r i a t i o n c o n s i d e r e d ,  source of e x p e r i m e n t a l animals  ( a r e a ) , and water p r o p e r t i e s ,  o n l y months and area show s i g n i f i c a n t main e f f e c t s ;  the main e f f e c t  water p r o p e r t i e s i s n o n - s i g n i f i c a n t .  indicate  These r e s u l t s  of  that  the o v e r a l l r e s p i r a t i o n of specimens changed from one month to the next and  that animals  from I n d i a n Arm  demonstrated  r e s p i r a t i o n r a t e from those the S t r a i t  of G e o r g i a .  a different The r e s u l t s  overall also  i n d i c a t e t h a t e i t h e r w i t h i n each of the two a r e a s , or between them, there was  no e f f e c t o f water p r o p e r t i e s ,  the same i n each a r e a .  The  significant  or t h a t these e f f e c t s were not i n t e r a c t i o n between areas  and months suggests t h a t the r e s p i r a t i o n of animals  from I n d i a n  changed d i f f e r e n t l y w i t h time from t h a t of the animals of  Georgia.  rest  Strait  Because of the s i g n i f i c a n t main e f f e c t of area i n the  overall analysis Strait  from the  Arm  (Table 11), r e s u l t s o b t a i n e d w i t h specimens from  of G e o r g i a and  of the a n a l y s e s .  from I n d i a n Arm  the  are t r e a t e d s e p a r a t e l y i n the  •-75A-  Figure 13a. (facing) Respiration of Euphausia p a c i f i c a from the S t r a i t of Georgia i n S t r a i t of Georgia upper and lower water and i n Indian Arm composite from A p r i l 1968 to September 1969 (Indian Arm composite from August 1968 to September 1969 only).  Figure 13b. (facing) Respiration of Euphausia p a c i f i c a from Indian Arm i n S t r a i t of Georgia upper and lower and i n Indian Arm Composite from March 1968 to September 1969.  1969  1968  I.A. composite  — — • —  -  G . S . upper water  G . S . lower water  -76The results of an analysis (Table 12) of the reactions of specimens from Indian Arm to Indian Arm and lower waters over 13 months indicate that there was  an o v e r a l l change i n  respiration rate with time (months) , but that there' were no consistent differences between responses to the two waters. Therefore, the results obtained with the two waters have been combined i n the graphic presentation of the data as 'Indian Arm composite water' (Figs. 13a, 13b). The r e s p i r a t i o n of E_. p a c i f i c a from the S t r a i t of Georgia i n the three waters over 13 months i s shown i n F i g . 13a.  An  obvious feature of the results shown i s that respiration i s a l l three waters declines from a higtt i n April-May 1968 to a low i n November-December 1968 and then increases u n t i l AugustSeptember 1969.  The fact that the high respiratory rate obtained  i n April-May 1968 was not maintained through July-August  1968  as i t was i n 1969 may be an i n d i c a t i o n of a cycle having a period of more than one y ear. t  Superimposed on the o v e r a l l seasonal v a r i a t i o n i n respiratory rate (Fig. 13a) i s a cycle of the ' d e s i r a b i l i t y ' of S t r a i t of Georgia upper and lower waters.  With the exception  of June 1968, from A p r i l to September 1968 r e s p i r a t i o n i n S t r a i t of Georgia upper i s higher, although at times only s l i g h t l y higher, than i n S t r a i t of Georgia lower water; from October 1968 to March 1969  the reverse i s true.  From A p r i l 1969  to July  1969  upper water i s again more 'desirable' than lower, but i n August 1969 the ' d e s i r a b i l i t y ' of the two waters reverses again. This cycle appears to have a seasonal basis; i n winter lower water i s more 'desirable' than upper; i n summer the reverse i s true.  -77-  Results of an analysis designed to test whether there was  any difference between the reactions of specimens from the  S t r a i t of Georgia to the S t r a i t of Georgia upper and lower during April-May 1968 and May-June 1969 They indicate that there was  are shown i n Table 13.  a s i g n i f i c a n t e f f e c t of water  properties, and that this e f f e c t was month and between 1968 and 1969.  consistent from month to  The four months included i n  the analysis were the two from each year i n which the 'summer' response to water properties was most f u l l y developed, if-e? the months showing the'greatest difference i n r e s p i r a t i o n rate between-Straitaof Georgia upper and lower waters. Table 14 shows the results of analysis of variance performed on the data obtained using animals from the S t r a i t of Georgia i n S t r a i t of Georgia upper and lower water f o r months when the 'winter' response to water properties obtained (October, November, and December 1968; January 1969).  In the results of  this analysis neither of the two sources of v a r i a t i o n considered, water properties and months, showed any s i g n i f i c a n t main effects. was 0.10  The probability of obtaining a larger F-ratio than  obtained for water properties (3.89) by chance l i e s hetween and 0.05.  Such a result indicates that water properties  may have had an e f f e c t on the respiration of the animals but that i f so, experimental error was  too great to allow i t to be  dis tinguished. Figure 13b gives a graphic presentation of the r e s p i r a t i o n of animals from Indian Arm i n the three waters  ( S t r a i t of  Georgia upper and lower; over 13 months Indian Arm  composite).  -78-  As  i n the r e s u l t s o b t a i n e d w i t h specimens from the S t r a i t o f  Georgia  ( F i g . 13a), an important f e a t u r e  r e s p i r a t i o n from J u l y  i s the d e c l i n e i n  1968 to December 1968 f o l l o w e d  i n r e s p i r a t i o n r a t e between January 1969 and J u l y  by a r i s e  1969.  Superimposed on t h i s g e n e r a l s e a s o n a l c y c l e a r e other e f f e c t s . During J u l y , August, and September 1969 r e s p i r a t i o n o f I n d i a n Arm animals i n I n d i a n Arm composite water i s c o n s i s t e n t l y h i g h e r than f o r the same p e r i o d  i n 1968.  There appears t o be a c y c l i c change i n the r e l a t i v e ' d e s i r a b i l i t y ' o f S t r a i t o f G e o r g i a upper and lower water. In J u l y and August 1968, and i n A p r i l , August 1969 S t r a i t  May, June, J u l y and  of G e o r g i a lower water i s more  than upper water. From September 1968 t o A p r i l G e o r g i a upper water i s more cycle  'desirable'  1969 S t r a i t of  than lower.  animals. With few e x c e p t i o n s ,  of G e o r g i a p r e f e r r e d Results  S t r a i t of Georgia  i n months when I n d i a n Arm animals found  S t r a i t of G e o r g i a upper water more  'desirable',  animals from the  the lower water.  of an a n a l y s i s  of the r e a c t i o n s  animals t o the three e x p e r i m e n t a l sea waters d u r i n g and  This  i s the r e v e r s e o f the one observed i n the r e l a t i v e  ' d e s i r a b i l i t y ' of the same two waters u s i n g  Strait  'desirable'  October 1968 and d u r i n g  of I n d i a n Arm August,  J u l y , August and September  September  1969 are  shown i n Table 15. T h i s a n a l y s i s was designed t o t e s t whether the i n t r u s i o n of outside see  sea water i n t o I n d i a n Arm (January-March 1969,  s e c t i o n I I I ) a f f e c t e d e i t h e r the a n i m a l s ' o v e r a l l r e s p i r a t i o n  r a t e or t h e i r r e a c t i o n s years i n d i c a t e s  that  t o water p r o p e r t i e s .  The l a r g e main e f f e c t o f  specimens' o v e r a l l r e s p i r a t o r y r a t e  changed  -79between 1968 interaction the  and 1969. At the same time the  between years and water p r o p e r t i e s  animals r e a c t e d  i n 1968  from the same depths and data  significant  differently  localities.  from i n 1969  and the most  that  t o waters  The g r a p h i c p r e s e n t a t i o n of the  ( F i g . 13b) suggests t h a t the i n t e r a c t i o n  f a c t t h a t I n d i a n Arm water i s l e a s t  indicates  arises  from the  ' d e s i r a b l e ' i n August  ' d e s i r a b l e i n J u l y and September 1969.  1968  The o t h e r  two waters, S t r a i t o f G e o r g i a upper and lower water, have the  same r e l a t i v e  ' d e s i r a b i l i t y ' i n August and September o f b o t h  years. The r e s u l t s  shown i n F i g u r e 13b suggest t h a t  Arm animals r e a c t e d to S t r a i t of G e o r g i a upper and i n the p e r i o d January to A p r i l 1969, did  i n the p e r i o d May  present the r e s u l t s  to August  differently  Indian  lower water  from what they  1969. T a b l e s 16 and  17  of an a n a l y s i s designed to t e s t  this  h y p o t h e s i s . In each i n s t a n c e s i g n i f i c a n t main e f f e c t s  are  o b t a i n e d f o r months and water p r o p e r t i e s . These  results  suggest t h a t specimens  differently  from I n d i a n Arm do r e a c t  to S t r a i t of G e o r g i a upper and lower waters d u r i n g the two periods. Monthly e s t i m a t e s of the abundance of a d u l t and E. p a c i f i c a a t s t a t i o n  I.A.-9 are shown i n T a b l e 19. These  e s t i m a t e s were o b t a i n e d by summing the numbers of E, 3 per  m  juvenile  pacifica  f o r the v a r i o u s depths at which they were caught. The  s m a l l Clarke-Bumpus p l a n k t o n samplers used to c o l l e c t samples are q u i t e l i k e l y  the  i n e f f i c i e n t w i t h r e s p e c t t o the  swimming e u p h a u s i i d s , but there i s no r e a s o n t o suppose  fast that  they were any more i n e f f i c i e n t i n one month than i n another.  -80Therefore, although the absolute abundances shown i n Table 19 are probably i n c o r r e c t , the r e l a t i v e comparison of abundances from one month to another i s probably v a l i d . The most important points to notice are that the  I  abundance of adult _E. p a c i f i c a ranges between 10.6 from September 1968 to January 1969.  and  In February 1969  E_. p a c i f i c a were caught, and from A p r i l to June 1969 were caught; i n May  1969  July to September 1969  1.5/m  3  no  only a few  juvenile E. p a c i f i c a appear and from  the numbers of adult _E. p a c i f i c a  present are considerably higher than from February to June  1969.  Discussion. One of the s a l i e n t features of the results obtained with specimens from both Indian Arm and the S t r a i t of Georgia i s that there i s a large seasonal v a r i a t i o n i n respiratory rate, the summer rate being higher than the winter rate. Similar seasonal v a r i a t i o n i n respiratory rates has been reported f o r calanoid copepods by Marshall and Orr (1958) , Anraku (1964) , Topping  (1966) and by Haq  (1967).  Small and  Hebard (1967)>however, report no seasonal v a r i a t i o n i n respiration of an oceanic population of E.  pacifica.  I t was  suggested by Small and Hebard that perhaps the r e l a t i v e l y unchanging thermal environment of the oceanic animals might have resulted i n t h e i r having l i t t l e or no seasonal changes in t h e i r respiratory rate. In the present study the respiratory rate of both coastal populations of E.  p a c i f i c a increases i n January,  long before the surface temperature increases appreciably i n April-May.  Therefore, i t appears unlikely that the seasonal  changes i n respiratory rate r e f l e c t seasonal changes i n the  -81TABLE 11 Results of analysis of variance:  Analysis of a l l data  obtained over 13 months using Euphausia p a c i f i c a from both Indian Arm and the S t r a i t of Georgia i n four sea waters.  Source of Variation  Sum of Squares  Months  80.520  Mean Square  df  F-ratio  6.7100  12  48.45** 13.69**  Populations  1.8961  1.8961  1  Water properties  0.019426  0.006475  3  Months x populations interaction  5.8027  0.48356  12  3.49**  Months x water properties i n t e r a c t i o n  5.7891  0.16081  36  1.16  Populations x water properties i n t e r a c t i o n  0.17679  0.058929  3  0.42  Months x populations x water properties i n t e r a c t i o n  9.7701  0.27139  36  57.61184  0.13849  416  Error Total  161.58  519  0.05  1.96**  -82-  TABLE 12 Results of analysis of variance:  Reaction of Euphausia  p a c i f i c a from Indian Arm to Indian Arm upper and" lower water over 13 months.  Source of V a r i a t i o n Mon ths  Sum of Squares 17.361  Mean Square 1.4468  df  F-ratio  12  11.70**  Water properties  0. 01223  0.01223  1  0.10  Months x water properties i n t e r a c t i o n  1. 7977  0.14981  12  1.21  Error  12.86375  0.125689  Total  32.035  104 129  -83TABLE 13 Results  of analysis of variance:  Reactions of Euphausia  p a c i f i c a from the S t r a i t of Georgia to S t r a i t of Georgia upper and lower water during 'low s a l i n i t y '  conditions  in 1968 i A p r i l , May) and i n 1969 (May, June).  Source of Variation  Sum of Squares  Mean Square  df  F-•ratio  Years  0.066178  0.066178  1  0. 206  Months  0.029214  0.029214  1  0.09  2.5427  2.5427  1  7.93**  Years x months interaction  0.17200  0.17200  1  0.54  Years x water properties i n t e r a c t i o n  0.060451  0.060451 .  1  0. 19  Months x water properties i n t e r a c t i o n  0.015406  0.015406  1  0.05  Years x months x water properties i n t e r a c t i o n  0.00002722  0.00002722  1  0.00  Water  properties  Error  10.25728  Total  13.143  0.32054  32 39  -84TABLE 14 Results of analysis of variance:  Reactions of Euphausia  p a c i f i c a from the S t r a i t of Georgia to S t r a i t of Georgia upper and lower waters during 'high s a l i n i t y ' conditions, winter 1968 - 1969 (November, December, January, February).  Source of Variation  Sum of Squares  Mean Square  df  F-ratio  Months  0.49837  0.16612  3  1.86  Water properties  0.34708  0.34708  1  3.89  Months x water properties i n t e r a c t i o n  0.091657  0.030552  3  0.34  Error  2.8528  0.08915  Total  3.7901  32 39  -85-  TABLE 15 R e s u l t s of a n a l y s i s o f v a r i a n c e : R e a c t i o n s of Euphausia pacifica  from I n d i a n Arm to S t r a i t  o f G e o r g i a upper,  Strait  of G e o r g i a lower and I n d i a n Arm composite waters d u r i n g August,  September and October 1968 compared  d u r i n g J u l y , August and  Source of V a r i a t i o n  w i t h those  September 1969.  Sum of Squares  Mean Square  df  F-ratio 50.29**  Years  4.2376  4.2376  1  Months  0.18021  0.090106  2  1.07  Water p r o p e r t i e s  0.077720  0.038806  2  0.46  Years x months interaction  0.34969  0.17484  2  2.08  0.70957  0.35479  2  4.21*  Months x water properties interaction  0.59620  0.14905  4  1.77  Error  6.40407  0.08426  76  Years x water interaction  Total  properties  12.555  89  -86TABLE 16 Results of analysis of variance:  Reactions of Euphausia  p a c i f i c a from Indian Arm to S t r a i t of Georgia upper, S t r a i t of Georgia lower, and Indian Arm composite waters during February, March, A p r i l and May 1969.  Source of Variation  Sum of Squares  Mean Square  df  F-ratio  Months  1.4265  0.47549  3  4.43**  Water properties  1.3870  0.69349  2  6.46**  Months x water properties i n t e r a c t i o n -  1.0572  0.17620  6  1.64  Error  5.14896  0.10727  48  Total  9.0198  59  -87-  TABLE 17 Results of analysis of variance:  Reactions of Euphausia  p a c i f i c a from Indian Arm to S t r a i t of Georgia upper, S t r a i t of Georgia lower, and Indian Arm composite waters during June, July, August and September 1969.  Source of Variation  Sum of Squares  Mean Square  df  F-ratio  Months  1.65255  0.54183  3  5.12**  Water properties  0.68686  0.34343  2  3.25*  Months x water properties i n t e r a c t i o n  0.23414  0.039024  6  0.37  Error  5.0712  0.10565  48  Total  7.6179  59  -88-  TABLE 18 Results of analysis of variance:  Reactions of Euphausia  p a c i f i c a from Indian Arm to S t r a i t of Georgia upper, S t r a i t of Georgia lower, and Indian Arm composite waters during the period of February, March, A p r i l and May 1969 compared with t h e i r reactions to the same waters during the period June, July, August, and September 1969.  Source of Variation  Sum of Squares  Mean Square  df  F-ratio  Seasons  0.71441  0. 71441  1  6.81**  Months  1.5493  0. 51643  3  4.91**  Water properties  0.14895  0.074477  2  0.71  Seasons x months interaction  1.5027  0. 50089  3  4.77**  Season x water properties i n t e r a c t i o n  1.9249  0.96244  2  9.17**  Months x water properties i n t e r a c t i o n  0.81032  0. 13505  6  1.30  Error  10.70160  0. 10491  102  Total  17.352  119  -89-  TABLE 19 Abundance  o f a d u l t and j u v e n i l e Euphausia p a c i f i c a as 3  numbers/m  a  t I n d i a n Arm S t a t i o n 9:  d a t a from p l a n k t o n  samples c o l l e c t e d u s i n g the Clarke-Bumpus P l a n k t o n  Month September October  no. 1968  1968  adults/m  3  10.6  no. juvs 0  1.66  0  November 1968  1.50  0  December  4.00  0  2.50 .  0  0  0  January  1968 1969  February  1969  March  1969  April  1969  May  1969  no sample 0.2  no s 0  0.2  10.3  June 1969  0.14  12.1  July  2.6  0  1.2  8.8  1969  August  1969  samplers.  -90-  envlronmental  temperature.  The beginning of the increase, i n January, coincides neither with the change i n r e l a t i v e ' d e s i r a b i l i t y ' (Figs. 13a, 13b) nor with the change from 'high s a l i n i t y ' to 'low s a l i n i t y ' hydrographic conditions i n the S t r a i t of Georgia (see section III for a d e f i n i t i o n of 'high s a l i n i t y ' and 'low s a l i n i t y ' conditions).  Therefore the increase i n respiration rate does  not appear to be a r e s u l t of changes i n water properties. The time of the beginning of the increase i n respiratory rate, January, does coincide with the increase i n the daily photoperiod. Pearcy et a l (1969), however, were unable to demonstrate e f f e c t of l i g h t on the respiration of E_. p a c i f i c a .  any  They did  not attempt any long term photoperiod experiments. LIttlepage (pers. comm.)"'" has found that E_. p a c i f i c a from the l o c a l area dp cycle.  not appear to store food i n a seasonal  That i s , t h e i r chemical composition does not change  appreciably over a yearly cycle.  Therefore, the animals'  energy expenditure, which i s ultimately equivalent to i t s r e s p i r a t i o n rate, may be dependent on the amount of food available to i t .  Conover (1959) reports that the spring increase  i n the respiration of A c a r t i a discaudata, which has a seasonal cycle of respiration s i m i l a r to that observed for E_. p a c i f i c a , was  related to the increased a v a i l a b i l i t y of food i n the  spring; Conover and Corner (1968) report a s i m i l a r r e l a t i o n between respiration and feeding f o r several species of copepods. Therefore, i t appears l i k e l y that the seasonal v a r i a t i o n i n the respiratory rate of _E. p a c i f i c a from both areas-  1  Dr. J.L. L i t t l e p a g e , University of V i c t o r i a , V i c t o r i a , B r i t i s h Columbia.  -91may  r e s u l t from seasonal variations i n t h e i r food supply.  If  this i s true, the increase i n respiratory rate i n the early spring might be related to the appearance of large numbers of copepod n a u p l i i i n the water column (Stephens et a l , 1969). The seasonal cycle of high respiration i n summer and low r e s p i r a t i o n i n winter i s the only feature that i s common to the results obtained with animals from both the S t r a i t of Georgia and Indian Arm.  The  results of the s t a t i s t i c a l analysis  of the data (Table 11) indicate that not only are the o v e r a l l respiratory rates of specimens from the two areas d i f f e r e n t ( s i g n i f i c a n t main e f f e c t of areas), but also that t h e i r reactions to seasonal changes and to water properties are not the same ( s i g n i f i c a n t interactions for months x areas and months x area x water properties).  Because of the apparent differences  between reactions of specimens from the two areas, results from each w i l l be discussed  separately.  An i n t e r e s t i n g aspect of the results obtained with specimens from the S t r a i t . o f Georgia i s the cycle of r e l a t i v e ' d e s i r a b i l i t y ' of S t r a i t of Georgia upper and lower water (Fig. 13a).  This cycle appears to be related to changes i n  hydrographic conditions  i n the S t r a i t .  When 'high s a l i n i t y '  hydrographic conditions p r e v a i l i n the S t r a i t of Georgia, then lower water i s more 'desirable' than the upper water"; i n s a l i n i t y ' conditions 'low  the opposite s i t u a t i o n holds.  s a l i n i t y ' conditions  In F i g .  13a  are shown as obtaining i n the  S t r a i t of Georgia between A p r i l 1968  and September  regular sampling of temperature and s a l i n i t y was August 1968,  'low  but data available for May  and July  1968;  not begun u n t i l 1968  -92-  indicate that 'low s a l i n i t y ' conditions obtained at those timesi  Therefore, i t has been presumed that 'low s a l i n i t y '  conditions were continuous from A p r i l 1968 to September  1968.  An analysis of the data f o r the two months i n which the maximum response (greatest difference between r e s p i r a t i o n i n S t r a i t of Georgia upper and lower water) of S t r a i t of Georgia animals to 'low s a l i n i t y ' conditions i n each of 1968 and 1969  (Table 13) indicates that the magnitude of the responses  to S t r a i t of Georgia upper and lower waters did not change from 1968 to 1969,  and that the differences i n respiratory  rates obtained were r e a l .  At the same time, inspection of  F i g . 13a suggests that, although there are differences i n the specimens' reactions between the two years, the pattern of response to S t r a i t of Georgia upper  and lower waters during  'low s a l i n i t y ' conditions i s consistent i n both years. Initially  ( A p r i l , May  1968; May, June 1969) S t r a i t of Georgia  upper water i s appreciably more 'desirable' than lower; this period i s followed by one i n which the two waters are equally 'desirable' (June, July, August, 1968; J u l y , August f i n a l l y the t r a n s i t i o n  1969);  to the 'high s a l i n i t y ' response takes  place (October 1968; September 1969). The above pattern of response suggests that the difference between the two waters arises as a result  of some  event and that the property causing the difference i s then slowly' equalizedbbetween them. May  One event which occurs during  and June each year i s the time of the peak runoff from the  Fraser River (Waldichuck, 1957).  Thus i t i s possible that the  observed pattern of response i s a result of the addition at the  -93surface of the S t r a i t of Georgia of some 'desirable' property i n the runoff water. Analysis of the r e s p i r a t i o n of specimens from the S t r a i t of Georgia i n S t r a i t of Georgia upper and lower water during the period when 'high s a l i n i t y ' conditions obtain (Table 14) i s inconclusive.  The p r o b a b i l i t y of obtaining a larger F-ratio  than that observed f o r water .properties i s less than 0.10% and greater than 0.05%; perhaps the results of this analysis can be said to suggest that the observed differences i n the effects of S t r a i t of Georgia upper and aioweriwaters (Fig. 13a) on the euphausiids' respiration may be. r e a l , but not to prove the point conclusively.  In any event the pattern of response  to 'high s a l i n i t y ' hydrographic conditions, the greater ' d e s i r a b i l i t y ' of S t r a i t of Georgia lower water, i s consistent from October 1968 to February 1969. The primary feature of the results obtained with specimens of j i . p a c i f i c a from Indian Arm i s an o v e r a l l seasonal cycle of r e s p i r a t i o n with the winter respiratory rates being less than, those i n summer; this cycle possibly results from the same causes as the one discussed above for S t r a i t of Georgia animals. The results of the analysis of the Indian Arm animals' reactions to water from the upper zone, where they l i v e , and from the lower zone (Table 12) show that there i s no detectable difference i n t h e i r reaction to the two waters.  The one month  i n t e r v a l between sampling used i n this study, of course, w i l l not, allow fluctuations having a period of less than one, or possibly two months,to be detected.  At the same time i t i s  reasonable to assume that any persistent differences between waters would have been detected.  Regan (1968-)1 did not  include water from the deep zone i n h i s experiments so i t i s not  possible to say what e f f e c t i t might have had on the  animals' s u r v i v a l .  I t does not appear, from the present  r e s u l t s , however, that there are any differences i n 'other-' propertie's' between the two waters. One of the more i n t e r e s t i n g features of the results i s that, on the whole, r e s p i r a t i o n i n Indian Arm composite water (Fig. 13b, Table 1!5>) i s higher i n August and September of 1969 than i n the same period of 1968.  A notable incident which  occurred between 1968 and 1969 was  the i n t r u s i o n of outside  water i n t o Indian Arm i n February-March 1969.  I t i s possible  that higher r e s p i r a t i o n rates observed f o r Indian Arm animals i n July and August 1969 as opposed to the same months of 1968 r e s u l t from changes i n the hydrography of the f j o r d .  It  appears, too, that, far from reacting adversely to intruding water as suggested by Regan (1968), the animals react favorably to i t as shown by t h e i r increased respiratory rates. I t i s possible that the increased r e s p i r a t i o n and changed reactions to Indian Arm composite water r e s u l t from the  use i n experiments of E_. p a c i f i c a recruited into Indian  Arm along with the intruding water.  Regan (1968), however,  considers the population of E_. p a c i f i c a l i v i n g i n Indian Arm to be indigenous and suggests that, rather than there having been a large i n f l u x of E_. p a c i f i c a at the time of the i n t r u s i o n which occurred during h i s study, specimens were l o s t from the i n l e t with the water displaced by the intrusion.  The same  -95-  course of events appeared to take p l a c e a t the time o f the i n t r u s i o n i n February-March  1969,  the p o p u l a t i o n  density  o f E_. p a c i f i c a a t s t a t i o n 9 (Table 19) dropped s h a r p l y i n February 1969 1969.  and remained  low u n t i l b r e e d i n g began i n May  Thus i t appears l i k e l y  specimens  from I n d i a n Arm  t h a t a t l e a s t a m a j o r i t y of the  employed  i n the experiments were  from the i n d i g e n o u s p o p u l a t i o n . i  The s i g n i f i c a n t seasons x water p r o p e r t i e s  interaction  seen i n T a b l e 18 suggests t h a t , although the main e f f e c t of water p r o p e r t i e s i s n o n - s i g n i f i c a n t , the I n d i a n Arm animals' r e a c t i o n to water p r o p e r t i e s d i f f e r s The s i g n i f i c a n t e f f e c t s  i n w i n t e r from i n summer.  f o r water p r o p e r t i e s observed i n the  r e s u l t s o f the a n a l y s i s shown i n Tables 13 and 17 c o n f i r m t h a t t h e r e are e f f e c t s on the r e s p i r a t i o n of animals caused by d i f f e r e n c e s i n water  properties.  In g e n e r a l , d u r i n g the p o s t - i n t r u s i o n p e r i o d I n d i a n Arm  composite water i s always about the same i n i t s e f f e c t s  E_. p a c i f i c a from I n d i a n Arm G e o r g i a upper or lower water Strait  to May  as the more p r e f e r r e d of S t r a i t of ( F i g . 13b).  I n d i a n A"rm 'uahimals :  of G e o r g i a upper water g i v e h i g h e r r e s p i r a t o r y  than those i n S t r a i t 1969.  o f G e o r g i a lower water from October  From June to August S t r a i t  1968  of G e o r g i a lower  In September 1969  o r d e r of p r e f e r e n c e changes  With s m a l l d i s c r e p a n c i e s  again.  in  rates  water i s p r e f e r r e d to upper water.  (one month a t most) the t i m i n g o f the changes  the  i n the o r d e r o f  p r e f e r e n c e , the p r e f e r e n c e shown by the I n d i a n Arm Strait  on  animals f o r  of G e o r g i a upper lower water i s the i n v e r s e of the c y c l e  seen i n the r e s u l t s G e o r g i a ( F i g . 13a).  o b t a i n e d w i t h animals from the S t r a i t of Because o f the correspondence of the  -96-  dates of changing preference,  i t appears that both  populations  are responding to changes i n the same properties i n a d i f f e r e n t way. In sum, the results of this experiment show that specimens of E_. p a c i f i c a from the S t r a i t of Georgia and from Indian Arm can detect and react to differences i n 'other' water properties.  I t has also been shown that specimens from  Indian Arm and the S t r a i t of Georgia do not react to 'other' properties i n the same way:  changes i n 'other' properties  have been related to changes i n oceanographic processes.  -9 7VII.  GENERAL DISCUSSION. The presence or absence of a species i n an area or  water i s probably a result of the action of a l i m i t i n g factor. Such a l i m i t i n g factor may be presumed to operate through stresses i t imposes. research was  The o v e r a l l object of the present  to gain an insight into the effects on Euphausia  p a c i f i c a of factors; that might act to l i m i t the d i s t r i b u t i o n of the species.  To this end the effects of changes i n the  temperature, s a l i n i t y and 'other' properties of sea water on the animals' r e s p i r a t i o n have been investigated. The results reported i n Part IV provide an estimate of the ranges of values of temperature and s a l i n i t y that are tolerable to E_. p a c i f i c a ; they suggest that, as Regan (1968) proposed, these two factors w i l l only be important i n l i m i t i n g the d i s t r i b u t i o n of E. p a c i f i c a i n B.C.  coastal waters near  the surface where the temperature of the water may become high, or low, and i t s s a l i n i t y low. Results reported i n Part V demonstrated that changes i n 'other' properties between sea waters could exert stress on E_. p a c i f i c a and, further, provided a means, through, comparing respiratory rates obtained at 10° C, of assessing differences i n the 'other' properties of a series of sea waters. The question remains as to what causes the d i f f e r e n t responses to the various waters.  Because a l l the animals used  i n this study were treated a l i k e , except for the water that they were placed i n , i t i s unlikely that the observed differences between sea waters were an a r t i f a c t of experimental technique. At the same time, although the i n s i t u temperature and s a l i n i t y  -98-  of the water varied over a year's time (Tables 9 and 10) i t seems l i k e l y that measuring the animal's r e s p i r a t i o n after acclimation at a constant temperature eliminated any effects of d i f f e r i n g i n s i t u temperatures.  The changes i n s a l i n i t y  at any one depth do not exceed 1 o/oo, and are generally less (Tables 9 and 10). Changes i n s a l i n i t y of less than 1 o/oo affect the r e s p i r a t i o n of E_. p a c i f i c a only at values of s a l i n i t y much lower than any encountered i n the f i e l d away from the surface.  Also, when the r e l a t i v e ' d e s i r a b i l i t y ' of upper and  lower water from the S t r a i t of Georgia to specimens from each of the two populations changes, the r e l a t i v e s a l i n i t i e s of the two water do not (Table 10).  These results suggest that the  differMg.g responses to various sea waters do not ensue on changes i n i n s i t u s a l i n i t y .  I t appears, rather, that the  d i f f e r i n g responses result from changes i n other, but undefined, properties of the water. Because of the close coincidence of the changes i n the ' d e s i r a b i l i t y ' of S t r a i t of Georgia upper and lower water with changes from 'high s a l i n i t y ' to 'low s a l i n i t y ' oceanographic conditions i n the S t r a i t (see Part I I I f o r a d e f i n i t i o n of these conditions), the changes i n 'other' properties of these two waters may be linked to the origins of the waters (Part I I I ) . Further evidence of the close correlation of changes i n 'other' properties with changes i n the origins of water i s furnished by the fact that Indian Arm composite (see Part VI f o r a d e f i n i t i o n of Indian Arm Composite) appears to have been more 'desirable' to specimens from Indian Arm after the intrusion than before.  From this i t may be deduced that 'other' properties  -99-  are at least quasi-conservative  properties of sea water.  Lewis and Ramnarine (1969) and Lewis (pers. comm.) have found that by enriching S t r a i t of Georgia lower water with chelated cobalt and zinc during  'low s a l i n i t y ' hydrographic  conditions i t s value as a culture medium for copepod larvae i s enhanced, presumably by supplying or making available, needed trace elements.  During 'high s a l i n i t y ' conditions,  however, enrichment of S t r a i t of Georgia lower water either provides no b e n e f i t , or i s harmful to the copepod larvae.  Lewis  and Ramnarine interpret this r e s u l t as i n d i c a t i n g that the trace elements were already present i n s u f f i c i e n t  quantities  and that the enrichment, or the added chelation, raised the usable trace element concentration  to a toxic l e v e l .  Thus,  i t can be i n f e r r e d that the contentlofietrace elements i n S t r a i t of Georgia lower water when 'high s a l i n i t y '  conditions  p r e v a i l i s higher than when 'low s a l i n i t y ' conditions  obtain.  Because animals from the S t r a i t of Georgia find S t r a i t of Georgia lower water more 'desirable' when i t s trace element content can be i n f e r r e d to be high, perhaps S t r a i t of Georgia upper water can be i n f e r r e d to have a higher trace element content than the lower water when i t i s more 'desirable' than lower water (during 'low s a l i n i t y ' conditions). I f the above reasoning i s v a l i d the cycle of the relative  ' d e s i r a b i l i t y ' of S t r a i t of Georgia upper and lower  water to specimens from the S t r a i t of Georgia could be explained i f both upwelled oceanic water and Fraser River runoff were sources of trace elements.  Thus, the lower water would be  the most 'desirable' to animals from the S t r a i t of Georgia i n late summer and early winter when the bottom waters are  -100displaced by water containing recently upwelled water ('high s a l i n i t y conditions'); the upper water would be most 'desirable' i n late spring and early summer when trace elements were added at the surface by the i n f l u x of Fraser River runoff. The water resident i n Indian Arm i s ultimately derived from the water i n the upper zone of the S t r a i t of Georgia, and probably always i n late winter.  Thus, i f as has been proposed,  the trace element content of the water i n the upper zone of the,Strait of Georgia i s low i n late winter, the waters resident , i n Indian Arm could be expected to have a low trace element content. Specimens of E. p a c i f i c a from Indian Arm react more favourably to whichever of S t r a i t of Georgia upper or lower water that can be i n f e r r e d at that time to have the lower ' trace element content.  This s i t u a t i o n implies! that the optimum  concentration of trace elements for specimens from Indian Arm i s lower than f o r specimens from the S t r a i t of Georgia.  Such  a s i t u a t i o n could be expected to arise i f the trace element content of the water i n Indian Arm were lower than that of the water i n the S t r a i t of Georgia. From this i t seems necessary to postulate that the Indian Arm population has become adapted to a p a r t i c u l a r set of 'other'properties  (low trace element concentration?) of  the water i n Indian Arm.  Thus these specimens reacttoo  outside, properties (higher concentrations of trace elements?) d i f f e r e n t l y from another population (from the S t r a i t of Georgia) that has become adapted to the l a t t e r conditions.  The fact that  -101-  the intrusion of outside water did not appear to a f f e c t the c h a r a c t e r i s t i c response of the Indian Arm animals to S t r a i t of Georgia upper and lower water suggests that the adaptation may be genetically fixed and not just an acclimatization.  I f so,  i t would suggest that free passage of E_. p a c i f i c a between the S t r a i t of Georgia and Indian Armmmay be limited by stresses a r i s i n g from the persistent differences i n 'other' properties between the waters of these two areas.  A genetic adaptation  would also suggest that these two groups form two separate p h y s i o l o g i c a l races of E_. p a c i f i c a which d i f f e r with respect to t h e i r reactions to 'other' properties of sea water.  This  bears out Regan's (1968) hypothesis that the Indian Arm E_. p a c i f i c a might comprise a separate population, d i s t i n c t from specimens i n EheaStrait of Georgia. The results of Part V~suggest that the water y i e l d i n g the higher r e s p i r a t i o n rate under a standard set of experimental conditions permits the animals to support a greater amount of stress.  Therefore, i t i s possible that the changes i n the  r e l a t i v e ' d e s i r a b i l i t y ' of S t r a i t of Georgia upper and lower water represent changes i n the r e l a t i v e s u i t a b i l i t y for E. p a c i f i c a of the two waters. . The occurrence of euphausiids i n the S t r a i t of Georgia as revealed by h o r i z o n t a l plankton tows were usually confined to two or three of the depths sampled with one of the samples containing the majority of the specimens captured.  S t r a i t of Georgia upper water was  always  collected from the depth of greatest abundance of euphausiids. I t seems therefore either that changes i n the r e l a t i v e  -102-  s u i t a b i l i t i e s of S t r a i t of Georgia upper and lower water were not great enough to affect the v e r t i c a l d i s t r i b u t i o n of E_. p a c i f i c a i n Georgia S t r a i t or that such changes i n d i s t r i b u t i o n were not detected.  The absence of s i m i l a r differences i n the  s u i t a b i l i t y of the upper and lower waters from Indian Arm an specimens from there suggests that there are no such differences i n 'other' properties as e x i s t between S t r a i t of Georgia upper and lower waters between the upper and lower waters from Indian Arm.  This r e s u l t implies that the occurrences of  _E. p a c i f i c a at mid-depth i n Indian Arm observed by Regan (19680  1  as w e l l as i n the result of this study probably do not result from an avoidance of deleterious 'other' properties of deep water i n Indian Arm. The above arguments concerning the d i s t r i b u t i o n of E. p a c i f i c a do not rule out the p o s s i b i l i t y that differences i n 'other' properties between Indian Arm and the S t r a i t of Georgia might l i m i t the free passage of animals from the S t r a i t of Georgia into Indian Arm.  In f a c t , the inverse (Part VI)  reactions of specimens from the two areas to the same water properties suggests that free passage between the two areas may be limited. The above arguments concerning the d i s t r i b u t i o n of E. p a c i f i c a are based on i t s observed d i s t r i b u t i o n .  The methods  and equipment used to determine the distributionoof euphausiids, namely s t r a t i f i e d tows with Clarke-Bumpus samplers leave much to be desired ,nneve r the les ss, used consistently , they w i l l provide a reasonably accurate estimate of the depth of maximum abundance of specimens.  The author believes that more  -103-  e f f i c i e n t sampling equipment would have y i e l d e d e s s e n t i a l l y the same picture of the d i s t r i b u t i o n of the euphausiids. In summary, temperature,  s a l i n i t y and 'other' water  properties are a l l capable of exerting stress on specimens of E_. p a c i f i c a and thus are p o t e n t i a l l y capable of acting to l i m i t the species' d i s t r i b u t i o n of occurrences. from the observed  At the same time,  tolerances of coastal euphausiids  (Part IV)  to changes i n temperature and s a l i n i t y i t appears that these two factors could affect d i s t r i b u t i o n of E_. p a c i f i c a only at or near the surface.  Thus i t i s a reasonable deduction that  any effects of water properties on E. p a c i f i c a ' s ' i d i s t r i b u t i o n away from the surface i n the l o c a l area w i l l be a r e s u l t of the action of 'other' properties. In neither Indian Arm nor i n the S t r a i t of Georgia was there a demonstrable e f f e c t of 'other' properties on E_. pacifica's distribution.  However, differences between the areas were such  that there may be some l i m i t a t i o n of free passage of specimens between Indian Arm and the S t r a i t of Georgia as a r e s u l t of theaaction of the 'other' properties.  At the same time i t i s  not d i f f i c u l t to see how a species which was less tolerant to changes i n 'other' properties could be limited i n i t s d i s t r i b u t i o n of occurrences by the observed d i s t r i b u t i o n of the 'other' properties either i n the S t r a i t of Georgia or between Indian Arm and the S t r a i t of Georgia. The results of the present study indicate that the e f f e c t of 'other' properties on the d i s t r i b u t i o n of planktonic animals may be greater, and the e f f e c t of temperature and  -104s a l i n i t y less than has been previously considered (Kinne, 1964)., A deeper insight into the ecology of plankton animals would seem to await a greater knowledge of 'other' properties and their effects on zooplanktonic organisms.  -105-  VIII. SUMMARY AND  CONCLUSIONS.  Temperature and s a l i n i t y and other unidentified properties have been suggested asffactors acting to l i m i t the d i s t r i b u t i o n of planktonic organisms through the stresses they impose.  The objective of this study was  experimentally E. p a c i f i c a .  to examine  the e f f e c t s of stress on the r e s p i r a t i o n of Both immediate and long term effects were  examined by means of acute measurements of the effects of the property(ies) i n question on specimens from populations  of  E) p a c i f i c a resident i n areas that d i f f e r e d , or could be presumed to d i f f e r , with respect to the property(ies) under investigation. The  f i r s t properties whose effects were investigated  were temperature and s a l i n i t y ; not only can these properties be measured i n the f i e l d , but they can also be readily manipulated i n the laboratory.  At the same time waters d i f f e r i n g  i n t h e i r c h a r a c t e r i s t i c values of temperature and s a l i n i t y having resident populations  and  of IS. p a c i f i c a were available for  s tudy. The results of the experiments using specimens of E. p a c i f i c a resident i n oceanic, mixed oceanic-coastal, and coastal waters show that large, and consistent differences occur i n j t h e i r tolerances of changes i n the temperature and s a l i n i t y of their environment.  These differences are correlated with the  c h a r a c t e r i s t i c temperatures and s a l i n i t i e s of the waters i n which the animals were l i v i n g .  Specimens from the warmest and  most d i l u t e water (coastal) showed the greatest tolerances  to  changes i n temperature and s a l i n i t y ; animals from the cooler  -106-  and less d i l u t e oceanic water had the least tolerance.  Specimens  from mixed oceanic-coastal water possess tolerances intermediate between those of the above groups.  These results suggest that  the long term effects of l i v i n g i n environments which demonstrate progressively greater "changes i n temperature and s a l i n i t y has been to expand the tolerances of specimens l i v i n g i n the more variable environments; the three populations of _E. p a c i f i c a employed i n this study may constitute separate p h y s i o l o g i c a l races of E_. p a c i f i c a . The results of the investigation into the acute effects of changed temperature and s a l i n i t y demonstrated that a sharp reduction i n respiratory rate could be used as an i n d i c a t i o n of stress.  At the same time, the results of these experiments showed  that as the values of temperature and s a l i n i t y approach the l i m i t s of tolerance the effects of stress from these sources interact. Experiments taking advantage of the i n t e r a c t i o n between the effects of temperature and s a l i n i t y were used to establish that differences i n the non-measurable,  'other' properties  between sea waters could impose additional stress on adult E_. pacifica.  At the same time a simple method of assessing the  effects of differences i n 'other'pproperties between sea waters through a comparison of respiratory rates obtained i n a number of sea waters under standard experimental conditions was developed. The experiment designed to investigate the long term effects of changes i n 'other' properties of sea water used sea water and specimens of E_. p a c i f i c a from two areas, Indian Arm  -107and the S t r a i t of Georgia.  The reactions of these two groups  of specimens to water from two depths i n each area was over a period of 14 months.  observed  The results of the survey  indicated that the 'other' properties of a given sea water appeared to depend on the o r i g i n of the water; changes i n the d i s t r i b u t i o n with time and with depth of 'other' properties are correlated with changes i n oceanographic conditions. The equally close c o r r e l a t i o n of the results of enrichment studies using trace elements suggest that observed changes i n 'other' properties may  be related to changes i n the trace  element content of the sea waters.  There were opposite  reactions  of E_. p a c i f i c a from the S t r a i t of Georgia and from Indian  Arm  to two waters that can be i n f e r r e d to have d i f f e r e n t trace element contents.  This inference suggests that E_. p a c i f i c a  resident i n Indian Arm may be adapted to a lower  concentration  of trace elements than E_. p a c i f i c a resident i n the S t r a i t of Georgia. In neither Indian Arm nor i n the S t r a i t of Georgia i s there any evidence to show that differences i n 'other' properties (possibly the concentration of trace elements) as shown by this study affects the d i s t r i b u t i o n of E. p a c i f i c a . The results of this study do not, however, rule out p o s s i b i l i t y that free passage of specimens of E. between Indian Arm  the  pacifica  and the S t r a i t of Georgia might be l i m i t e d  by differences i n 'other' properties between the  areas.  - 108Th e results of this study show that changes i n temperature, s a l i n i t y , and  'other' properties  can a l l exert stress on  adult E_. p a c i f i c a ; animals from areas that d i f f e r with  respect  to the various properties have been shown to adapt to those differences. to the sum  I t i s also indicated that the animals are reacting  of a l l stresses imposed on them.  A better under-  standing of the ecology of marine zooplanktonic organisms w i l l have to involve i d e n t i f y i n g and elucidating the mode of action of what have been loosely c a l l e d 'other' properties i n the course of this study.  -109IX.  REFERENCES  ALDERDICE, D.F. 1963. 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U.K., 37: 331-348. a  „ 1961. B i o l o g i c a l differences between sea waters: Experiments i n 1960. J. mar. B i o l . Assn. U.K., 41: 663-680. WOHLSCHLAG, D.E. and J.N. CAMERON, 1957. Assessment of a low l e v e l stress on the respiratory metabolism of the p i n f i s h (Lagodon rhomboides). Contrib. mar. S c i . Univ. Texas, 12: 160-171.  115 APPENDIX  1  RESPIRATION RATES OBTAINED FOR SPECIMENS OF EUPHAUSIA PACIFICA DURING THE COURSE OF THE EXPERIMENTAL PROGRAM.  Respirationcrates and s a l i n i t y  obtained  under a v a r i e t y o f c o n d i t i o n s  f o r specimens captured  Salinity  a t S t n . P a c . - l i n February 1969.  Temperature 5°CZ  10°C  d d d d d  Zl%<,  15°C  d d d d d  d d d d d  24&>  0.758 1.291 0.906 1.147 0.776  1.823 1.117 1.526 0.985 d  1.822 2.151 d d. rid  Zl%o  1.298 2.146 1.145 1.220 1.456  1.885 1.768 2.281 2.161 0.869  2.740 3.240 1.383 1.973 1.528  1.016 1. I l l 1.139 1.029 0.686  1.518 1.182 1.171 2.362 2.089  34&  R e s p i r a t i o n r a t e s obtained and s a l i n i t y  o f temperature  24&>  * specimen d i e d  1.438 1.347 2.916 1.986 1.155  under the above', c o n d i t i o n s  f o r specimens captured  lit,  .  d d d d d 1.154 1.217 0.934 0.569 0.852 i n acclimation  o f temperature  a t S t n . P a c . - l i n June 1969. d d d d d  1.015 1.350 1.686 1.288 1.425  d d d d d  1.353 1.516 1.574 1. 965 1.669  116  5°C 1.624 0.945  Iff™  1.076 1.270 1.592 1.016 1.162  1.251 1.338 2.206  10°C  15°C  1.254 2.137 1.727 1.027  1.771 2.013 1.591 1.844 2.088  1.610  2.013  1.172 2.149 2.075 1.756  1.856 3.102  1.864  1.404 2.267  Respiration rates obtained underaa variety of conditions of temperature and s a l i n i t y using specimens captured  at Stn. J.F.-9 i n November 1968. d d d d d  0.568 0.262 0.342 0.389 0.326  0.881 0.741 0.730 0.444 0.498  0.453 0.592 0.463 0.748  0.533 0.752 0.629 0.911  1.505 1.139 1.379 1.425  ZTfoo  0.541 0.697 0.645 0.269 0.514  0.527 1.688 1.086 1.405 0.800  1.162 0.993 1.270 1.656 0.922  3lto  0.559 0.585 0.592 0.473 0.427  0.801 0.645 0.909 1.134 0.872  1.126 1.024 0.766 1.272 1.442  3$o  0.567 0.573 0.865 0.950 1.190  0.999 0.898 0.782 0.584 0.813  1.334 1.549 1.529 1.570 0.969  21&  24l  Respiration rates obtained under the above conditions < and s a l i n i t y for specimens captured 0.382 0.652 d d d  at Stn.J.F.-9 i n ,  0.582 0.542 d d d  d d d d d  117  5°C  10°C  15°C  24&  0.364 0.797 0.955 0.689 1.375  1.218 1.203 1.431 1.308 1.057  1.551 1.459 1.962 0.964 d  27&  1.017 1.091 0.966 0.973 0.788  1.505 1.229 1.486 1.234 0.708  1.659 2.139 0.995 1.223 1.778  3l%o  0.951 0.574 0.708 1.536 1.253  1.461 1.584 1.284 1.279 1.300  1.184 1.683 1.370 1.027 1.672  1.134 1.286 0.811 1.047 1.274  1.361 0.825 0.766 1.274 1.731  0.985 2.342 2.054 1.621 2.022  Respiration rates obtained  under a variety of conditions of temperature  and s a l i n i t y using specimens captured  at Stn. SAA.-4 i n February 1969.  21&  1.133 0.739 0.723 0.729 0.830  1.633 1.630 1.906 1.223 1.339  1.954 3.421 3.108 2.960 2.720  27&  0.898 2.291 0.847 1.309 0.542  2.034 1.317 1.663 1.381 1.997  3.811 4.348 4.104 3.403 2.682  30l  1.357 1.645 0.813 1.539 1.338  0.987 2.341 1.120 1.527 1.590  6.703 3.085 4.785 3.893 3.498  118  Respiration rates obtained under the above conditions and s a l i n i t y for specimens captured 5°C  10°C  15°C 1.090 1.708 1.542  0.860  0.650 1.665 1.246 1.439 1.154  1.424 0.978 1.152 0.826 1.246  2.270 1.179 1.273 2.173 2.056  0.934 2.087 1.866 2.416 1.825  1.508 1.965 1.963 0.598 1.193  2.602  2.432 2.321 23394 1.226 2.823  1.027 0.859 0.830 0.693  3 (Zoo  at Stn.SAA.-4 i n .  1.661  1.800  1.742 2.257 1.908 2.636  Respiration rates obtained under a variety of conditions of temperature and s a l i n i t y i n four d i f f e r e n t sea waters using specimens captured at Stn. G.S.-l, May 1969. water  f u l l strength sea water  sea water d i l uted to ZlXo  measurements at 10°C G.S. upper (GSU)  G.S. lower (GSL)  I.A. upper (IAU)  1.744  1.807  2.382 1.830  1.268  1.665  1.488  1.934 1.593  1.730  3.673  1.495  1.410  1.361  1.281  1.698  1.495 1.469  3.207 1.807  1.169 2.331 3.288 2.088 3.018  1.162  1.683 1.221 2.061 1.635  119  f u l l strength sea water  sea water d i l uted to Zlto  2.080 2.151 2.821 2.126 1.674  1.344 1.986 1.809 1.979 1.778  I. A. lower (IAL)  measurments at 15°C GSU  1.688 2.139 3.043 2.935 1.766  2.304 2.089 3.331 2.396 2.228  GSL  2.778 2.863 2.479 2.683 2.708  1.674 2.378 2.780 2.899 2.802  IAU  3.922 3.014 3.960 2.683 3.655  1.814 1.833 1.956 1.855 1.875  IAL  2.029 2.820 d d d  2.271 2.039 1.976 2.010 1.717  Respiration rates obtained under a variety of conditions of temperature and s a l i n i t y i n five different sea waters using specimens captured at Stn. water  G.S.-l, July 1969. f u l l strength sea water  sea water d i l uted to 2l%o  sea water d i l uted to 1$4  measurements at 10°C GSU  1.936 1.924 1.665 2.592 1.504  1.347 1.759 1.266 1.388 1.427  d d d d d  120  f u l l strength sea water  sea water d i l uted to Zl%  GSL  1.987 1.656 1.599 1.958 1.681  1.448 1.725 d d d  IAU  2.397 2.028 2.062 1.624 2.580  0.995 1.532 1.311 1.871 1.528  IAL  2.092 1.471 2.310 1.444 2.262  2.057 1.734 1.361 1.412 1.526  J.F. 250*  2.399 1.949 1.779 2.309 2.109  1.620 1.508 1.479 1.897 1.445  0  sea water d i l uted to d d d d d 1.335 d d d d d d d d d 1.518 d dd  d d  measurements made at 15°C GSU  3.096 2.976 3.242 2.646 2.456  1.800 d d d d  d d d d d  GSL  2.422 1.587 1.954 1.719 2.148  2.036 d d d d  d d d d d  IAU  3.425 3.806 2.500 3.200 2.222  2.724 2.155 2.124 2.616 d  d d d d d  IAL  1.978 2.486 3.067 4.389 3.423  1.690 2.832 3.045 2.419 d  d d d d d  * water collected at a depth of 250m at Stn. J.F.-9.  121  J.F. 250  f u l l strength sea water  sea water d i l uted to 21%o  1.990 2.232 2.929 3.098 3.139  2.130 1.988 d d d  sea water d i l uted to 18&> d d d d d  Respiration rates obtained under a variety of conditions of temperature and s a l i n i t y i n four d i f f e r e n t sea waters using specimens captured at Stn. water  G.S.-l, August 1969. f u l l strength sea water  sea water d i l uted to 21^o  measurements made at 10°C GSU  1.793 1.799 1.857 1.657 2.256  1.885 1.852 2.251 1.837 1.868  GSL  2.880 1.554 2.063 2.584 2.270  1.431 1.893 1.724 1.918 1.741  IAU  2.312 1.488 2.168 1.793 1.940  1.924 1.073 1.223 1.626 1.518  IAL  1.605 1.839 1.677 2.322 1.860  1.295 0.969 2.052 1.820 1.617 measurements made at 15°C  GSU  1.393 1.571 2.486 2.138 2.046  2.348 1.511 2.576 2.165 3.451  122  f u l l strength sea water  sea water d i l uted t o ZlXo  GSL  3.074 2.402 2.070 2.684 3.434  3.567 2.228 3.209 2.405 d  IAU  1.685 1.692 2.787 2.079 3.188  3.747 4.081 d d d  IAL  1.933 2.403 1.930 3.152 3.079  1.367 2.075 2.817 2.512 4.555 measurements made a t 20°C  GSU  3.197 2.910 2.857 3.094 2.512  GSL  2.805 2.901 2.584 2.856 3.135  IAU  IAL  I n d i a n Arm, A p r i l  d d d d d  d d d d d  d d d d d  d d d d d  d d d d d  R e s p i r a t i o n r a t e s obtained sea water c o l l e c t e d  2.190 d d d d  .  for  specimens  from I n d i a n Arm i n f u l l  from two depths i n each o f the S t r a i t  1968 to September 1969.  .  strength  o f G e o r g i a and  123  month A p r i l 1968  IAU  IAL  1.780  1.602 1.482 1.528 2.106 May 1968  2.088 1.956 2.160 1.814 1.683  GSU  GSL  1.700 2.550 1.841 1.918 2.351  1.184 1.544 1.832. 2.202 1.952  1.453 2.183 2.246 1.566 2.201  2.060 2.955 2.890 2.107 2.837  no d a t a f o r June 1968 J u l y 1968  1.135 1.442 0.770  August 1968  0.878 0.653 0.770 0.850 0.680  1.287 0.807 1.426 1.173 1.120  1.441 0.792 1.456 1.229 1.250  1.502 1.562 1.401 1.443  September 1968  1.409 1.803 1.293 1.175 1.366  1.862 1.174 1.298 0.713 1.432  2.024 0.733 1.308 0.789 2.190  1.124 1.197 0.991 1.496 1.530  October 1968  0.930 0.533 1.154 0.632 0.863  0.839 0.730 1.303 1.239 0.679  0.970  0.780  0.850 0.766 0.822 0.715 0.768  1.563 1.139 0.530 0.795 1.007  0.795 0.696 1.071 0.895 0.805  1.078 1.127 1.398 0.864 0.925  0.743 0.939 0.919 0.875  0.858 1.016 0.911 1.011 0.975  1.003 0.886 0.787 0.861 0.885  0.643 0.785 0.645  0.938 1.148 1.072 1.132 0.928  1.182 1.463 1.626 0.838 1.056  November 1968  December 1968  January 1969  1.092 1.483 1.356  0.611  0.779  0.617  1.610  1.161  1.143  0.802 0.643 0.596 0.773 0.564  1.888 1.721 0.944 1.840 1.194  0.952 1.391 1.118 0.968 1.107  0.612  124 month  IAU  IAL  GSU  GSL  February 1969  1.602 1.122 2.028 1.615 1.076  1.272 1.740 1.271 1.522 1.740  2.098 1.196 1.765 1.901 1.809  1.285 1.154 1.280 1.466 1.688  March 1969  1.505 1.502 1.676 1.552 2.196  2.225 1.421 1.641 2.515 1.998  .1.752-1.682 2.037 1.429 1.725  1.420 1.098 1.280 1.311  1.563 2.093 1.015 2.174 1.568  2.592 0.900 0.646 1.662 0.802  1.623 2.024 2.265 1.089 1.750  1.367 1.616 1.044 1.375 1.439  May 1969'  1.514 1.409 1.052 1.837 1.878  1.431 2.321 1.573 2.183 1.324  1.559 1.578 2.043 1.603 1.232  1.890 1.713 1.683 1.229 1.629  June 1969  1.742 1.468 1.483 1.545 2.339  1.320 1.492 1.699 1.467 0.983  1.301 1.182 1.422 0.977 1.139  1.542 1.198 1.234 1.799 2.023  J u l y 1969  2.230 1. 943 1.910 2.027. 1.981  2.043 1.724 2.233 2.001 1.993  1.772 1.471 1.778 1.674 1.667  0.774 2.396 2.508 1.893 1.903  August 1969  1.574 1.306 1.479 1.448 1.505  1.873 2.122 1.328 1.831 1.995  1.310 1.212 1.732 1.600 • 1.463  1.684 l.Z©0 1.677 1.843 1.661  September 1969  1.560 1.536 1.696 1.682 1.938  2.063 1.768 1.876 1.988 1.973  1.581 2.052 1.501 1.523 1.827  1.539 1.712 1.538 1.162 1.522  April  1969  1.322  125 Respiration rates obtained for specimens from the S t r a i t of Georgia i n f u l l strength sea water collected from two depths i n each of Indian Arm and the S t r a i t of Georg;ia, A p r i l 1968 to September month  IAU  IAL  GSU  GSL  1.770 2.243 1.913 2.178 2.239  2.115 1.770 1.202 1.318  May 1968  1.857 2.890 1.721 1.888  1.102 1.460 1.849 1.219  June 1968  1.856 1.503 1.058 2.502 1.652  1.84*2 1.562 1.832 1.969  A p r i l 1968  July 1968  1.738 0.888 1.351 1.417 1.189  August 1968  1.130 1.469 1.8632 1.303 1.214  2.610  1.600  2.037 2.170 1.126 0.943 1.389 1.322  1.606  1.002 1.296 1.100  1.257 1.026 1.277 1.291  0.802 0.836 0.843 1.019 0.874  1.216  September 1968  1.046 1.289 1.118 1.357 1.274  1.325 1.698 1.335 1.530 1.299  1.625 1.026 1.455 1.671 1.550  1.286 1.470 1.244 1.340 0.878  October. 1968  1.141 1.053 1.667 0.966 1.268  1.129 1.107 0.535 0.814 1.129  1.462 1.311 0.955 0.846 1.088  0.899 1.858 1.798 0.795 1.187  November 1968  1.439 0.648 0.793 1.028 0.976  1.064 0.791 1.185 0.880 0.979  1.048 0.740 0.922 0.891  1.080 0.788 0.934 0.920 0.850  1.006  126 month  IAU  IAL  GSU  GSL  December 1968  0.643 0.388 0.451 0.651 0.415  0.542 0.628 0.709 0.709 0.323  1.243 1.289 0.572 0.712 0.660  1.087 1.081 1.070 0. 963 1.361  January 1969  1.045 0.882 1.071 0.732 0. 968  0.719 0.845 0. 962 0. 949 0.609  1.229 0.892 0. 996 0. 904 0. 958  0.780 0.810 1.264 1.483 1.721  February 1969  1.313 1.530 1.391 1. 912 1.536  1.072 2.588 1.381 1.430 1.616  2.303 1.397 1. 908 1.809 1.856  1. 165 1.995 1.646 1.565 1.366  no data for March 1969 A p r i l 1969  1. 175 1.628 0.843 0.754 1.239  2.881 2.284 1.359 1.433 1.989  2.077 1.865 1. 131 1.823 1.009  1.308 1.356 2.033 1.501 1.302  May 1969  1.679 2.331 3.288 2.088 3.018  2.080 2.151 2.821 2. 126 1.674  1.744 1.819 2.382 1.665 1.488  1.730 1.493 1.281 1.495 1.465  June 1969  2.257 1.729  1.541 1.564 1.563 1. 340 596 l ., 971.977 ' 2. 1. 962 1.637  1.757 2.458 1.394 1.876 2.644  1.304 1.741 1.398 1.610 0. 963  July 1969  2.397 2.028 2.062 1.624 2.580  20092 1.471 2.310 1.444 2. ?,62  1.936 1.924 1.665 2.592 1.504  1.987 1.656 1.599 1. 958 1.681  August 1969  1. 946 2.312 1.488 2. 168 1.7 93  1.605 1.839 1.860 1.677 2.322  1.793 1.799 1.857 1.657 2.256  2.880 1.554 2.063 2.584 2.270  September 1969  1.931 1.716 1.759 1.672 1.718  2.058 2.609 2.694 1.695 1.792  1.592 1.346 1.622 1.868 1.607  2.381 1.659 2. 195 2.201 2.424  

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