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Promontory induced tidal mixing in a narrow channel : effects on nutrient concentrations, primary productivity… St. John, Michael A. 1989

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PROMONTORY INDUCED TIDAL MIXING IN A NARROW CHANNEL: EFFECTS ON NUTRIENT CONCENTRATIONS, PRIMARY PRODUCTIVITY AND ZOOPLANKTON STANDING STOCK By MICHAEL A. ST.JOHN B.Sc. U n i v e r s i t y of B r i t i s h Columbia, 1984 A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY i n THE FACULTY OF GRADUATE STUDIES (Department of Oceanography) We accept t h i s t h e s i s as conforming t o the r e q u i r e d standard THE UNIVERSITY OF BRITISH COLUMBIA August 1989 (Staichael A. S t . John, 1989 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 it 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 or her representatives. It is understood that copying or publication of this thesis for financial gain shall not be allowed without my written permission. Department The University of British Columbia Vancouver, Canada DE-6 (2/88) ABSTRACT Horizontal mapping, a e r i a l photography, and current meter deployment have been used to i d e n t i f y a t i d a l l y induced mixing event about a promontory i n the S t r a i t of Georgia, B r i t i s h Columbia, Canada. Mixing plumes were observed to commence, downstream of Shingle Spit during ebb t i d e s when the mean v e l o c i t y for the water column reached a minimum of 12.7 cm.s-^. Mixing plumes on ebb t i d e s , were characterized by increased surface s a l i n i t i e s as well as increased n i t r a t e + n i t r i t e and phosphate concentrations. Increases i n concentrations of n i t r a t e + n i t r i t e of 2.6 pg a t - l - * and phosphate of 0.45 jjg a t . l ~ * were observed i n the euphotic zone associated with the mixing plumes. Nutrient additions were c o r r e l a t e d to an increase i n primary production of 13.8 mg Cm i n the mixed water as determined by the uptake of 14co32-. Estimates of t o t a l volume of upwelling during the s t r a t i f i e d months of June and July 1986 were performed allowing an estimation of the net f l u x of new nutrients into the euphotic zone during t h i s period. The t o t a l increase i n primary production due to mixing occurring downstream of Shingle Sp i t was determined experimentally to range between 910 and 2.2x10^ kg of "new production" compared to the R e d f i e l d stoichiometric estimate of from 1.4x10 to 3.0x10 kg of "new production" during June and July, 1986. Measurements of net flow i n Lambert Channel allowed determination of the destination of the increases i n primary production. I t i s suggested that u t i l i z a t i o n of increases i n primary production caused increases i n the zooplankton standing stock i n the region south of Lambert Channel and Hornby Island. Gut contents of adult Qncorhynchus kisutch caught i n the region contained zooplankton groups which were components of the increase of zooplankton standing stock. The presence of these zooplankton groups i n the gut contents suggests u t i l i z a t i o n of the increases i n zooplankton standing stock by predators further up the food chain. TABLE OF CONTENTS ABSTRACT i i TABLE OF CONTENTS i v LIST OF TABLES v i i i LIST OF FIGURES x i PREFACE r xix ACKNOWLEDGEMENTS xx Chapter 1 GENERAL INTRODUCTION 1 Chapter 2. H i s t o r i c a l Review (A) Physical Review of the Region 2.1 Introduction 6 2.2 Physiography 6 2.3 Currents 8 2.4 Winds 9 2.5 S a l i n i t y and Temperature D i s t r i b u t i o n s . . . 9 Chapter 2. H i s t o r i c a l Review (B) Review of Regional B i o l o g i c a l Oceanography 2.6 Introduction 2.7 Phytoplankton 10 10 2.8 Standing Stock 12 2.9 Primary Production 13 2.10 Nutrients 14 2.11 T i d a l Mixing 14 2.12 V e r t i c a l Pelagic Zooplankton Communities 15 2.13 Nearshore Zooplankton Communities 17 2.14 Major F i s h e r i e s Stocks 18 Chapter 3. Physical Oceanography 3.1 Introduction 19 3.2 Methods and Results 20 3.21 Net Flow 22 3.22 Meter Co r r e l a t i o n ...23 3.23 Current P r o f i l e s 32 3.24 Mixing V e l o c i t y 35 3.25 Horizontal Mapping 36 3.26 A e r i a l Photography 49 3.27 S a l i n i t y and Temperature P r o f i l e s 56 3.2 8 Volume Mixed 56 3.2 9 Flow C h a r a c t e r i s t i c s 63 3.3 Discussion 65 v i Chapter 4. B i o l o g i c a l Oceanography: Loc a l i z e d E f f e c t s 4.1 Introduction 68 4.2 Materials And Methods 70 4.21 Light Determination 7 0 4.22 Primary Productivity 71 4.23 Nutrient Analysis 79 4.24 Zooplankton Sampling 82 4.3 Discussion.... 86 4.31 Nutrient Additions 86 4.32 Primary Production 88 4.33 Zooplankton Distributions 90 4.4 Conclusions 91 Chapter 5. B i o l o g i c a l Oceanography: Regional E f f e c t s 5.1 Introduction 92 5.2 Methods .93 5.21 Zooplankton Sampling 93 5.22 Zooplankton Resource U t i l i z a t i o n 99 v i i 5.3 Results 101 5.31 Net Flow 101 5.32 Zooplankton D i s t r i b u t i o n 101 5.33 Amphipoda D i s t r i b u t i o n 106 5.34 Euphausiia D i s t r i b u t i o n I l l 5.35 Copepoda D i s t r i b u t i o n 117 5.36 Zooplankton Resource U t i l i z a t i o n 121 5.4 Discussion 122 5.41 Net Flow 122 5.42 Zooplankton D i s t r i b u t i o n 123 5.43 Resource u t i l i z a t i o n 124 5.5 Conclusions 126 Chapter 6. General Discussion 130 References Cited 135 Appendix 1 153 Appendix 2 213 v i i i LIST OF TABLES Table 3.1 V e r t i c a l Current P r o f i l e Data 33 Table 3.2 Current v e l o c i t i e s from Aanderaa meters at Station 2 at commencement of mixing 36 Table 3.3 A e r i a l photographs over Shingle Spit demonstrating mixing c h a r a c t e r i s t i c s 4 9 Table 3.4 Observations of period of mixing events by STD and v i s u a l determination 59 Table 3.5 Distance across mixed sections as well as maximum current v e l o c i t i e s from Aanderaa meter record as well as s a l i n i t i e s i n the various areas 62 Table 3.6 Reynolds number c a l c u l a t i o n and var i a b l e s used i n i t s c a l c u l a t i o n 64 Table 3.7 Richardson Number ca l c u l a t i o n s 64 Table 4.1 T-test and Mann-Whitney r e s u l t s of primary p r o d u c t i v i t y tests for June, July, and August, 1987 75 Table 4.2 Net primary production for each upwelling event and mean primary production over the three sampling periods (days 1-3) as determined by radioactive 1 4 C uptake 79 i x T a b l e 4.3 N i t r a t e + n i t r i t e and phosphate c o n c e n t r a t i o n s , s a l i n i t y and temperature of the i n i t i a l water samples at time of c o l l e c t i o n o b t a i n e d f o r primary p r o d u c t i v i t y d e t e r m i n a t i o n s i n June, J u l y , and August 1987 80 T a b l e 4.4 C o n c e n t r a t i o n s of n i t r a t e + n i t r i t e and phosphate d u r i n g 1986 and 1987 from a l l samples o b t a i n e d a t the s u r f a c e from mixed and s t a b l e water masses 81 T a b l e 4.5 Zooplankton d e n s i t i e s . m ( g r e a t e r than 202 pm) i n mixed vs s t a b l e samples as o b t a i n e d by pumping and s i z e s e p a r a t i o n i n the l a b o r a t o r y 8 7 T a b l e 5.1 Net flow v e l o c i t y and d i r e c t i o n i n Lambert Channel as determined from Aanderaa meters 101 T a b l e 5.2 T - t e s t and Mann-Whitney s t a t i s t i c s comparing the 1987 n o r t h vs south d i s t r i b u t i o n s of Amphipoda, E u p h a u s i i a , and Copepoda 102 T a b l e 5.3 T - t e s t and Mann-Whitney s t a t i s t i c s comparing the 1986 n o r t h vs south d i s t r i b u t i o n s of Amphipoda, E u p h a u s i i a , and Copepoda 103 X T a b l e 5.4 T - t e s t and Mann-Whitney s t a t i s t i c s comparing the d e n s i t i e s of Amphipoda, E u p h a u s i i a , and Copepoda between the June, J u l y , and August 1987 sampling p e r i o d s 104 T a b l e 5.5 T - t e s t and Mann-Whitney s t a t i s t i c s comparing the d e n s i t i e s of Amphipoda, E u p h a u s i i a , and Copepoda between the June, J u l y , and August 1986 sampling p e r i o d s 105 T a b l e 5.6 Prey groups u t i l i z e d by 0_;_ k i s u t c h per i n d i v i d u a l specimen 121 T a b l e 5.7 Summary of e l e c t i v i t y i n d i c e s 122 x i LIST OF FIGURES F i g . 2.1. L o c a t i o n of study s i t e 7 F i g . 3.1 Aanderaa c u r r e n t meter s t a t i o n s 21 F i g . 3.2 Long channel c u r r e n t v e l o c i t i e s from March 30 t o A p r i l 27, 1986 a t Lambert Channel Aanderaa S t a t i o n 1 (23) 24 F i g . 3.3 Long c h a n n e l c u r r e n t v e l o c i t i e s from March 30 t o A p r i l 27, 1986 at Lambert Channel Aanderaa S t a t i o n 2 (29m) 25 F i g . 3.4 Long channel c u r r e n t v e l o c i t i e s from March 30 t o A p r i l 27, 1986 at Lambert Channel Aanderaa S t a t i o n 2 (42m) 25 F i g . 3.5 Long channel c u r r e n t v e l o c i t i e s from May 25 t o June 22, 1986 at Lambert Channel Aanderaa S t a t i o n 2 (29m) 26 F i g . 3.6 Long c h a n n e l c u r r e n t v e l o c i t i e s from May 25 t o June 22, 1986 at Lambert Channel Aanderaa S t a t i o n 2 (42m) 26 F i g . 3.7 Long c h a n n e l c u r r e n t v e l o c i t i e s from June 22 t o J u l y 20, 1986 at Lambert Channel Aanderaa S t a t i o n 2 (29m) 27 F i g . 3.8 Long channel c u r r e n t v e l o c i t i e s from June 22 t o J u l y 20, 1986 at Lambert Channel Aanderaa S t a t i o n 2 (42m) 27 x i i F i g . 3.9 Long channel c u r r e n t v e l o c i t i e s from J u l y 20 t o August 17, 1986 a t Lambert Channel Aanderaa S t a t i o n s 2 (42m) 28 F i g . 3.10 Long channel c u r r e n t v e l o c i t i e s from J u l y 20 t o August 17, 1986 a t Lambert Channel Aanderaa S t a t i o n s 3 (42m) 28 F i g . 3.11 Long channel c u r r e n t v e l o c i t i e s from May 25 t o June 22, 1986 a t Lambert Channel Aanderaa S t a t i o n 3 (29m) 29 F i g . 3.12 Long channel c u r r e n t v e l o c i t i e s from May 25 t o June 22, 1986 at Lambert Channel Aanderaa S t a t i o n 3 (42m) 29 F i g . 3.13 Long channel c u r r e n t v e l o c i t i e s from June 22 t o J u l y 20, 1986 at Lambert Channel Aanderaa S t a t i o n 3 (29 m) 30 F i g . 3.14 Long c h a n n e l c u r r e n t v e l o c i t i e s from June 22 t o J u l y 20, 1986 at Lambert Channel Aanderaa S t a t i o n 3 (42m) 30 F i g . 3.15 Model I r e g r e s s i o n of Aanderaa c u r r e n t meter d a t a vs the Marine A d v i s o r s c u r r e n t d a t a at the same times and depths ..31 F i g . 3.16 Mean C u r r e n t v e l o c i t y r e q u i r e d t o induce mixing on an ebb t i d e i n Lambert Channel, the S t r a i t of Georgia 34 X l l l F i g . 3.17 Hours per day when mixing c o n d i t i o n s e x i s t i n Lambert Channel as w e l l as t o t a l mixing d u r i n g June and J u l y , 1986 (Ebb v e l o c i t i e s exceeding 10.5 cm.s -1 S.E.=1.5 N=5) 37 F i g . 3.18 Predetermined h o r i z o n t a l mapping c o u r s e , i n Lambert Channel 39 F i g . 3.19 S u r f a c e map of s a l i n i t y on June 18, 1986 d u r i n g f l o o d t i d e , maximum v e l o c i t y d u r i n g sampling p e r i o d (1320 t o 1530 P a c i f i c D a y l i g h t Time) from Aanderaa meters (Mean v e l o c i t y from 2 meters a t S t n . 2) 31.8 cm.s - 1. S c a l e 1:20,000 40 F i g . 3.20 S u r f a c e map of s a l i n i t y on June 19, 1986 d u r i n g ebb t i d e , maximum v e l o c i t y d u r i n g sampling p e r i o d (0651 t o 0954 P a c i f i c D a y l i g h t Time) from Aanderaa meters (Mean v e l o c i t y from 2 meters a t Stn. 2) 6.20 cm.s - 1. S c a l e 1:20,000 41 F i g . 3.21 S u r f a c e map of s a l i n i t y on June 20, 1986 d u r i n g ebb t i d e , maximum v e l o c i t y d u r i n g sampling p e r i o d (1145 t o 1243 P a c i f i c D a y l i g h t Time) from Aanderaa meters (Mean v e l o c i t y from 2 meters a t Stn. 2) 17.6 cm.s -1 S c a l e 1:20,000 42 3.22 S u r f a c e map of s a l i n i t y on June 21, 1986 d u r i n g ebb t i d e , maximum v e l o c i t y d u r i n g sampling p e r i o d (0745 t o 0948 P a c i f D a y l i g h t Time) from Aanderaa meters (Mean v e l o c i t y from 2 meters a t Stn. 2) 6.45 cm.s - 1. S c a l e 1:20,000 3.23 S u r f a c e map of s a l i n i t y on June 21, 1986 d u r i n g ebb t i d e , maximum v e l o c i t y d u r i n g sampling p e r i o d (0808 t o 0833 P a c i f D a y l i g h t Time) from Aanderaa meters (Mean v e l o c i t y from 2 meters a t Stn. 2) 11.80 cm.s - 1. S c a l e 1:5,000 3.24 S u r f a c e map of s a l i n i t y on June 22, 1986 d u r i n g ebb t i d e , maximum v e l o c i t y d u r i n g sampling p e r i o d (0815 t o 1049 P a c i f D a y l i g h t Time) from Aanderaa meters (Mean v e l o c i t y from 2 meters at Stn. 2) 11.25 c m .s - 1. S c a l e 1:20,000 3.25 Expanded s u r f a c e map of s a l i n i t y on June 22, 1986 d u r i n g ebb t i d e , maximum v e l o c i t y d u r i n g sampling p e r i o d (0815 t o 104 9 P a c i f i c D a y l i g h t Time)from Aanderaa meters (Mean v e l o c i t y from 2 meters a t Stn . 2) 11.25 cm.s - 1. S c a l e 1:5,000 X V F i g . 3.26 S u r f a c e map of s a l i n i t y on June 24, 1986 d u r i n g ebb t i d e , maximum v e l o c i t y d u r i n g sampling p e r i o d (0930 t o 1100 P a c i f i c D a y l i g h t Time) from Aanderaa meters (Mean v e l o c i t y from 2 meters a t S t n . 2) 10.5 cm.s - 1. S c a l e 1:20,000 47 F i g . 3.27 S u r f a c e map of s a l i n i t y on June 24, 1986 d u r i n g ebb t i d e , maximum v e l o c i t y d u r i n g sampling p e r i o d (1200 t o 1255 P a c i f i c D a y l i g h t Time) from Aanderaa meters (Mean v e l o c i t y from 2 meters a t St n . 2) 9.55 cm.s - 1. S c a l e 1:20,000 48 F i g . 3.28 A e r i a l photograph of mixing event i n Lambert Channel. Altitude=16,500 f t . ; Time =1325 ; Date=July 1, 1972 50 F i g . 3.39 A e r i a l photograph of mixing event i n Lambert Channel. Altitude=19,000 f t . ; Time=1135;Date=July 26, 1975 51 F i g . 3.30 A e r i a l photograph of mixing event i n Lambert Channel. Altitude=19,000 f t . ; Time=0920;Date=July 26, 1975 52 F i g . 3.31 I n t e r p r e t a t i o n of f i g u r e 3.28, a e r i a l photograph of mixing event i n Lambert Channel, A l t i t u d e = 16,500 f t . ; Time = 1325; Date = J u l y 1, 1972 53 xvi F i g . 3.32 Interpretation of figure 3.29, a e r i a l photograph of mixing event i n Lambert Channel. A l t i t u d e = 19,000 f t . ; Time = 1135; Date = July 26, 1975 ..54 F i g . 3.33 Interprtation of figure 3.30, a e r i a l photograph of mixing event i n Lambert Channel. A l t i t u d e = 19,000 f t . ; Time =""0920; Date = July 26, 1975 55 F i g . 3.34 V e r t i c a l p r o f i l e of s a l i n i t y and depth i n the mixing event as obtained on June 23, 1986 57 F i g . 3.35 V e r t i c a l p r o f i l e of s a l i n i t y and depth i n the mixing event as obtained on July 12, 1986 57 F i g . 3.36 V e r t i c a l p r o f i l e of s a l i n i t y and depth i n the mixing event as obtained on June 24, 1987 58 F i g . 3.37 V e r t i c a l p r o f i l e of s a l i n i t y and depth i n the mixing event as obtained on June 25, 1987 58 F i g . 4.1 Primary production as determined by radioa c t i v e ^ C uptake for incubated water samples during June, 1987 76 F i g . 4.2 Primary production as determined by radioactive ^ C uptake for incubated water samples during July 1987 77 x v i i F i g . 4.3 Primary p r o d u c t i o n as determined by r a d i o a c t i v e ^ C uptake f o r i n c u bated water samples d u r i n g August, 1987 78 F i g . 4.4 Copepod d e n s i t i e s . m o b t a i n e d by pumping i n the mixing g e n e r a t i o n s i t e and the a d j a c e n t s t a b l e water columns d u r i n g June, J u l y , and August, 1987 83 F i g . 4.5 Copepod n a u p l i i d e n s i t i e s . m o b t a i n e d by pumping i n the mixing g e n e r a t i o n s i t e and the a d j a c e n t s t a b l e water columns d u r i n g June, J u l y , and August, 1987 84 F i g . 4.6 T o t a l zooplankton d e n s i t i e s . m o b t a i n e d by pumping i n the mixing g e n e r a t i o n s i t e and the a d j a c e n t s t a b l e water columns d u r i n g June, J u l y , and August, 1987 85 F i g . 5.1 L o c a t i o n of the 20 southern S t a t i o n s u t i l i z e d f o r v e r t i c a l zooplankton sampling d u r i n g the 1986 season 94 F i g . 5.2 L o c a t i o n of the 12 n o r t h e r n S t a t i o n s u t i l i z e d f o r v e r t i c a l zooplankton sampling d u r i n g the 1986 season 95 F i g . 5.3 L o c a t i o n of the 14 southern S t a t i o n s u t i l i z e d f o r v e r t i c a l zooplankton sampling d u r i n g the 1987 season 96 F i g . 5.4 L o c a t i o n of the 12 n o r t h e r n S t a t i o n s u t i l i z e d f o r v e r t i c a l zooplankton sampling d u r i n g the 1987 season 97 x v i i i F i g . 5.5 H o r i z o n t a l d i s t r i b u t i o n of the group amphipoda a t the southern s t a t i o n s d u r i n g 9 J u l y , 1986. D e n s i t i e s i n numbers per m 107 F i g . 5.6 H o r i z o n t a l d i s t r i b u t i o n of the group amphipoda a t the northern s t a t i o n s d u r i n g 9 J u l y , 1986. D e n s i t i e s i n numbers per m 108 F i g . 5.7 Amphipoda d e n s i t i e s , d u r i n g the 1986 sampling p e r i o d s a t s t a t i o n s 109 F i g . 5.8 Amphipoda d e n s i t i e s , d u r i n g the 1987 sampling p e r i o d s at s t a t i o n s 110 F i g . 5.9 H o r i z o n t a l d i s t r i b u t i o n of the group e u p h a u s i i a a t the southern s t a t i o n s d u r i n g 9 August, 1987. D e n s i t i e s i n numbers per m 113 F i g . 5.10 H o r i z o n t a l d i s t r i b u t i o n of the group amphipoda a t the northern s t a t i o n s d u r i n g August, 1987. D e n s i t i e s i n numbers per m 114 F i g . 5.11 E u p h a u s i i a d e n s i t i e s , d u r i n g the 1986 sampling p e r i o d s at s t a t i o n s 115 F i g . 5.12 E u p h a u s i i a d e n s i t i e s , d u r i n g the 1987 sampling p e r i o d s a t s t a t i o n s 116 F i g . 5.13 Copepoda d e n s i t i e s , d u r i n g the 1986 sampling p e r i o d s at s t a t i o n s 118 F i g . 5.14 Copepoda d e n s i t i e s , d u r i n g the 1987 sampling p e r i o d s at s t a t i o n s 119 x i x P r e f a c e Due t o the scope of t h i s study, time and manpower d i c t a t e d the sampling frequency and i n t e n s i t y . The author r e a l i z e s t h a t more depth i n some areas would enhance the study but i n o r d e r t o accomplish the g o a l of e l u c i d a t i n g the p h y s i c a l and b i o l o g i c a l l i n k a g e s t h i s was not p o s s i b l e . In o r d e r t o i n c r e a s e the l e g i b i l i t y of the t h e s i s i t was f e l t by the committee t h a t i n some areas of the t h e s i s i t was a d v i s a b l e t o combine the methods and r e s u l t s s e c t i o n s . X X ACKNOWLEDGEMENTS I would l i k e t o thank my two s u p e r v i s o r s Dr. Timothy Parsons and Dr. Dan Ware f o r t h e i r a d v i c e , support and o c c a s i o n a l nudge through the d u r a t i o n of t h i s t h e s i s . I would a l s o l i k e t o thank the o t h e r members of my committee Dr. P a u l J . H a r r i s o n , Dr. Steve Pond, and Dr. Bob De Wreede f o r d i s c u s s i o n s and v a l u a b l e i n p u t on the t h e s i s i t s e l f . As t h i s t h e s i s c o v e r s so many d i f f e r e n t areas i n oceanography many people from the d i f f e r e n t d i s c i p l i n e s had e f f e c t s on the f i n a l outcome. In b i o l o g i c a l oceanography I would l i k e t o thank Dr. A l Lewis, Dr. Dave Mackas, Dr. Shawn Robinson, Dr. J e f f M a r l i a v e , Dr. F.J.R. T a y l o r , Ms. Anna Metaxas, Mr. P e t e r Thompson, Mr. Herb Herunter and Mr. B i l l C ochlan. In p h y s i c a l oceanography I would l i k e t o e s p e c i a l l y thank Dr. Steve Pond as w e l l as Dr. Paul Leblond, Dr. Pat Crean and Dr. Malcom Bowman. Thanks as w e l l t o the S k i p p e r s and crew of the R e v i s o r e s p e c i a l l y Bob T a y l o r and Gordy A l i s o n f o r i n s u r i n g t h a t t h e r e was never a d u l l moment and Mr. Jim Powlik f o r t e c h n i c a l a s s i s t a n c e . In the f i e l d I would l i k e t o thank Hugh McLean and David Jones and h i s magic v o l t m e t e r . S p e c i a l thanks t o Don Webb f o r h e l p i n the f i e l d , sound c r i t i c i s m and f r i e n d s h i p through the 5 years of t h i s t h e s i s and Dr. Steve MacDonald f o r keeping t h i n g s i n p e r s p e c t i v e . My deepest a p p r e c i a t i o n t o T e r r i S u t h e r l a n d f o r her x x i u n d e r s t a n d i n g , and m o t i v a t i o n i n the f i n a l s t a g e s . I would l i k e t o thank two people I de e p l y wish c o u l d be here f o r t h i s , my p a r e n t s . T h i s i s d e d i c a t e d t o you! Support f o r t h i s p r o j e c t was p r o v i d e d by the Department of F i s h e r i e s and Oceans through Drs. Tim Parsons and Dan Ware as w e l l as from Dr. Tim Parsons NSERC o p e r a t i n g grant and a Chevron Research F e l l o w s h i p . 1 CHAPTER 1  GENERAL INTRODUCTION The patchy d i s t r i b u t i o n of organisms i s believed to be a ubiquitous phenomenon i n the environment i n which we e x i s t . In the ocean, the d i s t r i b u t i o n of planktonic organisms i s dependant i n part upon the concentration of t h e i r e s s e n t i a l nutrients. In p a r t i c u l a r , the f i n e to coarse scale patchiness of autotrophic primary producers (Haury et a l . 1978) i s dictated by the d i s t r i b u t i o n and flux of nutrients i n the euphotic zone. In times of s t r a t i f i c a t i o n and nutrient l i m i t a t i o n , i n the euphotic zone, a disturbance (White and Pi c k e t t , 1985) to the water column r e s u l t i n g i n the addition of nutrient r i c h deep water w i l l cause an increase i n primary production. The r e s u l t i n g increase i n production w i l l be most evident when primary production i s already reduced due to the depletion of e s s e n t i a l nutrients i n the euphotic zone. The r e s u l t i n g patchy d i s t r i b u t i o n of organisms due to nutrient f l u c t u a t i o n s i s considered to be a necessary condition of l i f e i n the oceans (Longhurst, 1981). An increasing number of t h e o r e t i c a l and experimental i n v e s t i g a t i o n s suggest that v a r i a b i l i t y of nutrients and prey items i s a c r i t i c a l aspect f o r the s u r v i v a l of marine organisms (Haury et a l . 1978; Longhurst, 1981; Denman and Powell, 1984; Owen, 1989). Some of the mechanisms examined causing nutrient addition, and thus the patchy d i s t r i b u t i o n 2 of organisms include t i d a l mixing (Simpson and Hunter, 1974), shelf break fronts (Gatien, 1976), estuarine plume fronts (Bowman and Iverson, 1978), as well as eddy-induced upwelling (Bowman, 1986) (reviews by Denman and Powell, 1984; Legendre and Demers, 1984). Regions such as Peru or the An t a r c t i c , seas with large fluxes of "new" (Dugdale and Goering, 1967) nutrients i n t o the euphotic zone, tend to be the most productive regions i n the oceans (Ryther, 1969). These regions of high 'new production' lead to d i f f e r e n t species compositions, d e n s i t i e s , and d i s t r i b u t i o n s than regions of 'regenerated production' (Eppley and Peterson, 1979). Mechanisms causing the addition of new nutrients to the euphotic zone are extensively examined phenomena i n b i o l o g i c a l oceanography. The e f f e c t s of large scale oceanographic events on the nutrient regime have been well documented (eg. Simpson and Hunter, 1974; Gatien, 1976; Bowman and Iverson, 1978; Bowman, 1986) but the e f f e c t s of small scale p h y s i c a l processes have not been examined extensively. Langmuir c i r c u l a t i o n s have been examined with respect to d i s t r i b u t i o n s of organisms i n the v o r t i c e s (Stavn, 1971; Steele, 1976) but the e f f e c t s on nutrients l i m i t i n g primary production have not been examined. Internal waves have been observed to change the l i g h t regime of autotrophes below the nu t r i e o c l i n e , r e s u l t i n g i n a temporary increase i n primary production (Haury et a l . 1983; Cullen et a l . 1983; Fahnenstiel et a l . 1988), but estimations of 3 fluxes of nutrients are lacking. Zooplankton aggregations have been shown to r e s u l t due to small scale physical events, (Alldredge and Hamner, 1980; Hamner and Hauri, 1981; Omori and Hamner, 1982; Zavodnik, 1987). These studies have primarily demonstrated the aggregative properties of the physical phenomenon i n conjunction with behavioral a c t i v i t i e s of the zooplankters involved. Patchy d i s t r i b u t i o n s of planktonic organisms may also be induced by v a r i a t i o n s i n concentrations of l i m i t i n g n u t r i e n t s . These nutrient v a r i a t i o n s have been accredited with the v a r i a t i o n s of phytoplankton species composition and de n s i t i e s i n the ocean (Epply et a l . 1969; Titman, 1976; Turpin and Harrison, 1979). This v a r i a t i o n i n species composition and density has been termed "contemporaneous d i s e q u i l i b r i u m " . The disequilibrium theory proposes that microhabitats occur within r e l a t i v e l y small volumes of water (Richardson et a l . , 1970), which are p r i m a r i l y determined by the a v a i l a b i l i t y of nutrients (Peterson, 1975). T i d a l l y induced turbulent plumes have not been examined with respect to t h e i r impact on nutrient concentrations i n nutrient depleted, s t r a t i f i e d water columns. Turbulent t i d a l plumes have previously been observed through the use of i n f r a r e d and coas t a l zone colour scanners i n co a s t a l regions (Pingree, 1978; Pingree and Mardell, 1986) as well as i n narrow channels (Ohishi, 1984; Nishimura et a l . , 1984). Observations on the generation of turbulent plumes s i m i l a r to those examined here have been performed by Mason and King (1984). Their work was based on atmospheric flow over a succession of nearly two-dimensional ridges and v a l l e y s with a turbulent plume observed along the slope of the ridges. A turbulent plume which i n t e r f a c e s with a surrounding f l u i d creates a shear-layer between the two regions ( N e t t e r v i l l e , 1985). Brown and Roshko (1974) discovered "deterministic" eddy structures within the turbulent shear-layer, while Hernan and Jimenez (1982) demonstrated that mixing occurs i n the shear-layer i n short quick "gulps" through the quasi-regular formation of eddies Entrainment i s v i r t u a l l y complete a f t e r the eddy has been formed with the eddy being composed of approximately equal proportions of the two water masses. Mixing across s t r a t i f i e d surfaces has been determined where i n e r t i a l forces override viscous forces as observed when the Reynold number exceeds 10 (Breidenthal & Baker, 1985) . The volume of the f l u i d entrained w i l l be l i m i t e d by the degree of the s t a b i l i t y of the f l u i d (Atkinson, 1988). The s t a b i l i t y of a water column can be determined by c a l c u l a t i o n of the Richardson number, with entrainment events possible when values c a l c u l a t e d are less than one (Browand & Wang, 1972, Breidenthal & Baker, 1985). This t h e s i s describes the e f f e c t s of mixing, due to a promontory i n a narrow channel, on the concentrations of nutrients that l i m i t phytoplankton growth i n the euphotic zone. The volume of water mixed w i l l be determined by v e r t i c a l p r o f i l i n g of s a l i n i t y and temperature as well as 5 h o r i z o n t a l mapping. Data from moored and surface deployed current meters w i l l be u t i l i z e d to determine the amount of time that mixing i s occurring i n the region of the promontory. Flow c h a r a c t e r i s t i c s w i l l be determined through c a l c u l a t i o n s of the Richardson and Reynolds numbers and the n i t r a t e + n i t r i t e additions due the mixing around Shingle Spit estimated. Increases i n primary production due to 'new' n i t r a t e additions w i l l be examined u t i l i z i n g R edfield stochiometery as well as through radioactive techniques. The transport of increases i n primary production caused by the mixing events w i l l be determined through the u t i l i z a t i o n of moored Aanderaa current meters, and examinations of zooplankton standing stock i n the region w i l l e l ucidate the p o s s i b i l i t y of phytoplankton-zooplankton coupling i n the region. In order to determine i f increases i n zooplankton standing stocks are u t i l i z e d by t e r t i a r y consumers the stomach contents of a major predator on zooplankton w i l l be examined. 6 CHAPTER 2  HISTORICAL REVIEW  (A) PHYSICAL REVIEW OF REGION 2.1 INTRODUCTION This section gives a b r i e f review of the ph y s i c a l oceanography and the geography of Lambert Channel i n the Northern S t r a i t of Georgia. Very few data e x i s t f o r northern S t r a i t of Georgia region; what i s av a i l a b l e i s a general d e s c r i p t i o n of the Northern S t r a i t of Georgia as given by Thomson (1981). 2.2 PHYSIOGRAPHY Lambert Channel i s situated between Hornby and Denman Islands with the center of the channel located at approximately 124°41'W and 49°31'N (Fig 2.1). The south arm of the channel i s oriented at approximately 315° north, while the channel bends at approximately Shingle Spi t and i s oriented at roughly 34 3° to north. Mean depth of the channel i s approximately 30 m with depths reaching 112 m near Norris Rocks on the south end of the channel and exceeding 100 m again North of 124°44'W and 49°35'N. Figure 2.1 Location of the study area i n the S t r a i t of Georgia, B r i t i s h Columbia, Canada. 8 2.3 CURRENTS Lambert Channel i s i n the northern S t r a i t of Georgia and the following d e s c r i p t i o n (unless otherwise noted) comes from Thomson (1981). The northern S t r a i t of Georgia i s t y p i f i e d by weak and var i a b l e t i d a l currents with v e l o c i t i e s i n most of the region t y p i c a l l y around 10 cm.s - 1 with v e l o c i t i e s reaching up to 50 cm.s - 1 i n narrow channels. The actual t i d e i s p r i m a r i l y a combination of the M2 and constituents and semi-diurnal i n nature with the mean t i d a l range f a l l i n g between 3.20 and 3.35 m. The c i r c u l a t i o n i n the northern S t r a i t of Georgia i s counterclockwise i n d i r e c t i o n i n both surface layer and deep water, as determined through d r i f t b o t t l e studies as well as noted by Dr. P. Crean (pers. comm.). Wind induced currents i n the northern S t r a i t of Georgia have been suggested to be generally quite weak. Reasons for weak wind induced currents during the winter are ascribed to weak s t r a t i f i c a t i o n of the surface layers. The r e s u l t a n t maximum speed of surface water under a steady, along-the-S t r a i t wind i s only about 3% of the wind speed. Thus a steady 10 m.s - 1 wind w i l l induce a current near the surface of 30 cm.s - 1. During the summer due to greater thermal s t r a t i f i c a t i o n the wind induced currents w i l l be r e l a t i v e l y stronger perhaps 5% of the wind speed. 9 2.4 WINDS Surface wind v e l o c i t i e s i n the northern S t r a i t of Georgia between October and March are predominantly from the southeast. Speeds range between 4.5-9 m.s - 1 f o r -35 to 50% of t h i s period. From June u n t i l September winds are predominantly from the northwest; speeds are usually less than 4.5 m.s - 1 f o r -50% of t h i s period. 2.5 SALINITY AND TEMPERATURE DISTRIBUTIONS Water temperature varies i n the S t r a i t of Georgia with respect to depth and season. The water column can be divided i n t o two regions, the surface layer (less than 50 m) and the deep layer below i t . The deep water i s r e l a t i v e l y uniform throughout the year with temperatures ranging between 8-10°C over the e n t i r e S t r a i t . The surface layer e x h i b i t s the greatest v a r i a b i l i t y ; during the f a l l and winter a i r temperatures and storms reduce the surface water temperatures to as low as 5-6 °C. During spring, a i r temperatures increase and storm a c t i v i t y decreases allowing increased s o l a r energy retention i n the surface l a y e r s . Surface temperatures may reach up to 15 °C by the middle of May and i n July may exceed 20 °C i n some regions. Only i n regions of t i d a l mixing at the north and south extremes of the S t r a i t do surface temperatures remain low -10 °C. Regions of upwelling due to offshore winds e x i s t and reduction of surface temperatures are evident due to these events. S a l i n i t y , l i k e temperature, i s r e l a t i v e l y constant i n the deep layer below 50 m. The top of the deep layer i s generally defined by a s a l i n i t y of 29.5. Below the top of the deep layer s a l i n i t i e s increase to between 30.5 and 31.0 with the former being summer values and the l a t t e r i n d i c a t i v e of winter conditions. Surface values range from 27.0 to 29.5 but may be influenced l o c a l l y by r i v e r i n e input. (B} REVIEW OF REGIONAL BIOLOGICAL OCEANOGRAPHY 2.6 INTRODUCTION This section w i l l serve as an introduction to the b i o l o g i c a l parameters pertinent to the th e s i s i n the northern S t r a i t of Georgia. S i m i l a r to the physical oceanography of the region, most of the research performed has been done on the southern portion of the S t r a i t as well as the Johnstone S t r a i t region. Thus very l i t t l e i s known about the b i o l o g i c a l parameters i n the northern S t r a i t of Georgia, but as f a r as species composition and d e n s i t i e s , i t i s assumed that the study s i t e i s s i m i l a r to that found i n the r e s t of the S t r a i t . 2.7 PHYTOPLANKTON Phytoplankton species composition of the S t r a i t of Georgia i s t y p i c a l of the global composition observed i n 11 c o l d temperate c o a s t a l waters with some estuarine inf l u e n c e . Diatoms dominate the si z e f r a c t i o n greater than 20 pm i n the S t r a i t of Georgia (Harrison et a l . , 1983 for a review). The most common species (frequency and biomass) i s Skeletonema  costatum, a chain-forming c e n t r i c diatom, which occurs concurrently or s l i g h t l y a f t e r the spring bloom composed p r i m a r i l y of T h a l a s s i o s i r a spp. (Stockner et a l . , 197 9; Stockner and C l i f f , 1979). Blooms of these species are followed by blooms composed primarily of Chaetoceros spp., but these blooms also may be composed of Cerataulina  bergonii or Eucampia zoodiacus p a r t i c u l a r l y i n the c e n t r a l and southern S t r a i t . A bloom of large Coscinodiscus spp. follows i n the l a t e f a l l as numbers of diatoms decline (Stockner et a l . , 1979). The d i s t r i b u t i o n of photosynthetic f l a g e l l a t e s has been examined i n the S t r a i t of Georgia by C a t t e l l (1969) who observed 77 species of d i n o f l a g e l l a t e s of which 4 7 species were non-photosynthetic. Dino f l a g e l l a t e s were observed to achieve greatest abundance i n the summer with gymnoid d i n o f l a g e l l a t e s c o n t r i b u t i n g s i g n i f i c a n t l y to the spring bloom. C a t t e l l a l so observed that blooms of non-photosyntethic species such as Protoperidinium spp. occur second only to diatom blooms i n abundance i n the S t r a i t . Blooms of these non-photosynthetic species u s u a l l y occur i n e a r l y to mid-summer (F.J.R. Taylor, unpublished observations). Other species commonly observed to cause blooms are the chloromonad Heterosiqma akashiwo, the c i l i a t e Mesodinium rubruin as well as three d i n o f l a g e l l a t e s , (Alexandrium = Protogonyaulax) Protoqonyaulax acatenella, Protogonyaulax c a t e n e l l a , and Protogonyaulax tamarenses. as well as Gymnodinium sanguineum and Noctiluca s c i n t i l l a n s (Taylor, 1975; Watanabe and Robinson, 1979). Studies s p e c i f i c a l l y examining the northern S t r a i t of Georgia showed l i t t l e change i n species composition between the north and south regions (Stephens et a l . 1969; Perry et a l . , 1981; Haigh, 1988) with Skeletonema costatum being the dominant diatom i n both areas. Haigh (1988) and Perry et a l . (1981) determined that diatoms dominated i n the spring and e a r l y summer, with f l a g e l l a t e s dominating l a t e i n the summer. Diatoms were most abundant on the north and west side of the S t r a i t where s t r a t i f i c a t i o n was l e s s evident, while on the east side of the S t r a i t , photosynthetic nanoflagellates and photosynthetic d i n o f l a g e l l a t e s were more abundant (Haigh, 1988). Unfortunately a l l of these studies deal with samples taken either north of the Lambert Channel region or i n the center of the S t r a i t and very l i t t l e i s known of the nearshore environment (Harrison et a l . 1983). 2.8 STANDING STOCK The h o r i z o n t a l assessment of phytoplankton standing stock has t r a d i t i o n a l l y been examined by h o r i z o n t a l mapping techniques u t i l i z i n g a flow-through fluorometer or d i s c r e t e point samples (Stephens 1968: Parsons et a l . 1970; Mackas et a l . 1980; Parsons et a l . 1981; Perry et a l . 1981). These techniques measure chlo r o p h y l l fluorescence for a s p e c i f i c l o c a t i o n as i n point samples or i n the case of mapping, the fluorescence at a s p e c i f i c depth over a wide area. The area examined i n horizontal mapping i s dependent on the range of the v e s s e l . Recently, areal estimates of fluorescence i n the S t r a i t have been performed on the top 2-3 m of the water column u t i l i z i n g a colour spectrometer and comparisons were made with shipboard c h l o r o p h y l l estimates (Gower 1980; Parsons et a l . 1981). Chlorophyll a concentrations generally range from <1 3 3 mg.m i n the winter to >15 mg.m during spring or early summer blooms (Stockner et a l . 1979; Parsons et a l . 1981) with regions of high mixing e s p e c i a l l y i n the northern S t r a i t reaching l e v e l s from 3 to >5 pg.L - 1. Chlorophyll a concentrations vary seasonally with depth as well as h o r i z o n t a l l y . A deep water c h l o r o p h y l l maximum frequently occurs during the summer (Parsons et a l . 1970). 2.9 PRIMARY PRODUCTION Primary production estimates i n the S t r a i t of Georgia — 7 have v a r i e d from an annual production of 120 g C m (Parsons, 1970) to 345 g C m - 2 (Stockner et a l . 1979) with Harrison et a l . (1983) proposing that a reasonable annual estimate i s on the order of 280 g C m . Primary production begins to increase i n February, with a maximum production i n — 9 1 —7 — 1 May of 1.2 g Cm .d--1- and an mean value of 0.2 g Cm . d i n l a t e summer (Parsons, et a l . 1970; Parsons 1979). 2.10 NUTRIENTS Nutrient concentrations i n the S t r a i t of Georgia appear well above values which would r e s t r i c t the growth rate of phytoplankton, except during the period from May to September when surface n i t r a t e + n i t r i t e concentrations may reach l i m i t i n g l e v e l s below 1.0 p g . a t . l ~ 1 (Harrison et a l . 1983). Phosphate l e v e l s i n the S t r a i t may also drop to low l e v e l s (0.1 p g . a t . l ~ 1 ; Takahashi et a l . 1973) although regeneration (Antia et a l . 1963) i s regarded to be rap i d enough to prevent l i m i t a t i o n of phytoplankton growth rate. S i l i c a t e concentrations have been observed i n Saanich Peninsula to drop to as low as 1 p g . a t . l - 1 (Takahashi et a l . 1973) and laboratory experiments indicate that t h i s concentration should reduce primary p r o d u c t i v i t y f o r many species, p r i m a r i l y diatoms due to t h e i r s i l i c a t e f r u s t u l e s (Paasche 1973). 2.11 TIDAL MIXING Regions of t i d a l mixing have been examined f o r increases i n c h l o r o p h y l l fluorescence i n the S t r a i t of Georgia (Parsons et a l . 1981). Values c a l c u l a t e d by the s t a b i l i t y expression, log-^Q (h.u ), where h i s water depth i n meters and u i s the v e r t i c a l l y averaged water v e l o c i t y (m.s - 1) during t i d a l exchange, where examined f o r ch l o r o p h y l l a concentrations. Low values of c h l o r o p h y l l 15 where found associated with s t a b i l i t y c a l c u l a t i o n s of <0 i n d i c a t i n g that turbulence was' too great f o r phytoplankton growth, while values >0 were associated with high l e v e l s of c h l o r o p h y l l due to increased s t a b i l i t y a f t e r mixing, allowing u t i l i z a t i o n of new nutrients made a v a i l a b l e to phytoplankton i n the euphotic zone. In the S t r a i t of Georgia, high l e v e l s of chlorophyll were observed i n the northern and southern ends of the S t r a i t as well as among various i s l a n d masses. These observations confirmed the pre d i c t i o n s obtained from the s t a b i l i t y expression (Parsons et a l . 1981). 2.12 VERTICAL PELAGIC ZOOPLANKTON COMMUNITIES Examinations of B r i t i s h Columbia c o a s t a l species of zooplankton were begun by McMurrich (1916) and the species that he observed are t y p i c a l of the l a t e summer community seen today (Harrison et a l . 1983). Quantitative examinations were i n i t i a l l y performed by Campbell (1929a, 1929b), as well as by Hutchinson and Lucas (1931) with sustained research on zooplankton community structure begun by Legare (1957). The surface community of the S t r a i t i s dominated i n winter by small copepods, p a r t i c u l a r l y Pseudocalanus spp. as well as Paracalanus parvus f Oithona helolandica, and Corycaeus spp. During the winter the pelagic zooplankton community has a slow growth rate and a low' reproductive rate and grazes on small f l a g e l l a t e s (Koeller et a l . 1979), p a r t i c u l a t e organic material from runoff, and heterotrophic 16 microorganisms (Seki and Kennedy 1969; Seki et a l . 1969) as well as microzooplankton (Takahashi and Hoskins 1978). Upon commencement of the spring phytoplankton bloom, the winter surface community increases i n production. At t h i s time the recruitment of n a u p l i i and ea r l y copepodite stages of Neocalanus plumchrus from deep water dominates the surface community. Adult Calanus marshallae. Calanus  p a c i f i c u s , and Metridia p a c i f i c a also migrate to the surface from deep water upon commencement of the spring bloom. The migration of Neocalanus plumchrus stage V i n t o the deep water signals the beginning of the summer surface community (Harrison et a l . 1983). The resultant decrease i n grazing pressure causes an increase i n phytoplankton production, thereby allowing an increase i n growth and reproduction of Calanus marshallae. Calanus p a c i f i c u s , and Pseudocalanus spp. (Stephens et a l . 1969). Concurrent with the increase of these species i s an increase i n numbers of the ctenophore Pleurobrachia spp. as well as the leptomedusa Phialidium spp. i n the surface layer (Stephens et a l . 1969). During the f a l l the surface layer i s characterized by small blooms of Calanus marshallae. Calanus p a c i f i c u s . Pseudocalanus spp., and Metridia p a c i f i c a which p e r s i s t u n t i l winter storms and lack of so l a r r a d i a t i o n lead to winter conditions (Stephens et a l . 1969). The region from the base of the mixed zone to about 250 m i s dominated throughout the year by the euphausiid Euphausiia p a c i f i c a • These euphausiids are d i e l migrators which feed i n the surface layers during hours of darkness and migrate to depth during the day. Breeding and egg release i s c a r r i e d out i n the surface layers from spring to early f a l l with the n a u p l i i , calyptopis and ear l y f u r c i l i a stages remaining i n the surface layers. The deep water community (below 250 m) i s dominated from July u n t i l March by Neocalanus plumchrus, Calanus  marshallae. Calanus p a c i f i c u s . and Pseudocalanus spp. This community remains r e l a t i v e l y stable from July to March with very l i t t l e predation occurring (Harrison et a l . 1983). 2.13 NEARSHORE ZOOPLANKTON COMMUNITIES The nearshore region of the S t r a i t of Georgia i s (due to f l u s h i n g and mixing i n basins and recruitment of meroplanktonic species) by fa r the most v a r i a b l e component of the zooplankton community i n the S t r a i t of Georgia (Herlinveaux et a l . 1966). The most stable constituents of the nearshore zooplankton community are copepods of the genera A c a r t i a , Pseudocalanus. Centropages. and Epilabidocera, while the highly v a r i a b l e meroplankton constituent i s composed of juvenile decapods and decapod zoea as well as barnacle n a u p l i i (Levings et a l . 1983). In addition long periods of s t a b i l i z a t i o n of the water column may also lead to blooms of the larvacean Oikopleura. 18 2.14 MAJOR FISHERIES STOCKS Two major f i s h e r i e s e x i s t i n the S t r a i t of Georgia. One f i s h e r y i s based on the salmonids Oncorhynchus kisutch, Oncorhynchus tshawytscha. Oncorhynchus nerka, Oncorhynchus  keta, and Oncorhynchus qorbuscha. In the region of Hornby and Denman, there are no major spawning streams f o r salmonids. Thus the concentrations of ju v e n i l e salmonids found u t i l i z i n g the Hornby and Denman Island region must do so during t h e i r seaward migration (Groot et a l . , 1985). The other major f i s h e r y i n the S t r a i t of Georgia u t i l i z e s the P a c i f i c herring Clupea harenqus p a l l a s i . The Denman Island region (Dept. F i s h e r i e s and Oceans S t a t i s t i c a l Area 14) i s one of the major h i s t o r i c a l spawning s i t e s f o r t h i s species with egg survey data from 1951 to 1980 i n d i c a t i n g that up to 80% of the spawn from the S t r a i t of Georgia may be deposited i n the Denman Island region (Hourston et a l . 1972; Hourston and Haegele 1980; Hourston 1981). 19 CHAPTER 3  PHYSICAL OCEANOGRAPHY 3.1 I n t r o d u c t i o n Haury e t a l . (1978) proposed a c o n c e p t u a l frame work f o r t h e b i o l o g i c a l t i m e - s p a c e s c a l e s o f v a r i a b i l i t y i n t h e ocean b a s e d on a t h r e e d i m e n s i o n a l d i s p l a y o f t h e s p e c t r a l d i s t r i b u t i o n o f p h y s i c a l v a r i a b l e s i n t h e ocean (Stommel, 1963; Stommel, 1965). T h r e e - d i m e n s i o n a l d i s t r i b u t i o n s o f biomass v a r i a b i l i t y were used t o de m o n s t r a t e p o s i t i v e c o r r e l a t i o n between s i z e and d u r a t i o n o f p h y s i c a l phenomenon, r a n g i n g from ephemera on t h e c e n t i m e t e r s c a l e t o v a r i a b i l i t y o v e r t e n s o f thousands o f k i l o m e t e r s on t h e t i m e s c a l e o f c l i m a t i c changes. T h i s s t u d y w i l l examine t h e p h y s i c a l s c a l e d e f i n e d by Haury e t a l . (1978) as c o a r s e - s c a l e (1-100 km) and f i n e -s c a l e (meters t o hundreds o f m e t e r s ) . C o a r s e - s c a l e e v e n t s have been d e s c r i b e d as plume-type u p w e l l i n g e v e n t s ( e g . B e e r s e t a l . 1971; Walsh e t a l . 1977) w i d t h s o f o c e a n i c f r o n t a l zones ( e g . P i n g r e e e t a l . 1976; S a v i d g e , 1976), and i s l a n d wakes (eg. Uda and Us h i n o , 1958; Simpson and T e t t , 1986). C o a r s e - s c a l e p a t c h i n e s s i s on t h e o r d e r o f t h e ambit o f p e l a g i c o r g a n i s m s such as t h e major f i s h e r i e s s t o c k s i n t h e S t r a i t o f G e o r g i a , i n s e a r c h i n g f o r p r e y and mates. The s u r v i v o r s h i p o f a p o p u l a t i o n o r y e a r c l a s s may depend on t h e 20 mean patchiness f i e l d that the population experiences per generation (Haury et a l . 1978). Fine scale patchiness i s on the scale of i n d i v i d u a l i n t e r a c t i o n s f o r zooplankton. This scale as with the coarse-scale for nekton i s important for the i n d i v i d u a l s , " the population fate may depend on the scale of patchiness, on the s p a t i a l scale of populations, and on the temporal scale of generation times" (Haury et a l . , 1978). The objective of t h i s chapter w i l l be to determine the s p a t i a l and temporal extent of the mixing events occurring at Shingle Spit, Lambert Channel. Once the volume of water mixed i n t o the surface layers i s determined, the increase i n nutrients from deep water can be determined. An estimate of nutrient fluxes i n t o the surface euphotic zone w i l l enable the determination of the increase i n primary production due to the mixing event. 3.2 Methods and Results Aanderaa current meters were deployed at three l o c a t i o n s i n Lambert Channel, S t r a i t of Georgia during 1986 (Figure 3.1). Meters were deployed on March 12, 1986 at Stations 1 and 2. Station 1 had 1 Aanderaa meter deployed at 23 m while Station 2 had 2 meters, 1 deployed at 29 m and 1 at 42 m. These meters were removed and serviced on May 14, 1986 and were redeployed at Stations 2 and 3 with meters at both Stations placed at 29 and 42 m. Sampling for current Figure 3.1 Locations of Aanderaa meter deployment i n Lambert Channel, S t r a i t of Georgia. 22 analysis ended on September 12, 1986 when the Aanderaa meters were removed and serviced. During the period of time that the meters were deployed, s a l i n i t y , temperature as well as current speed and d i r e c t i o n measurements were obtained at 20 min i n t e r v a l s . In conjunction with the Aanderaa current meter data, p r o f i l e s of current speed were obtained downstream from the Aanderaa meters with a Marine Advisers Inc., Savonius rotor current meter. Current p r o f i l e s were obtained on both ebb and f l o o d t i d e s at various times during the t i d a l cycle at 2 m depth increments at each Station. The Marine Advisors current meter was allowed to s t a b i l i z e approximately 1 min. at each depth. A l l v e r t i c a l p r o f i l i n g was performed from an anchored v e s s e l , on days when wind v e l o c i t i e s were less than 1.5 m.s - 1, thus reducing wind e f f e c t s on the water column. 3.21 Net Flow In order to determine net flow i n Lambert Channel and thus a s c e r t a i n the destination of nutrient additions due to mixing events, the average along channel flow was cal c u l a t e d from the Aanderaa current meter record. Current v e l o c i t i e s obtained from the Aanderaa meters were i n the form of v e l o c i t i e s i n the north (v) and east (u) d i r e c t i o n s . These data were converted to a long channel component following the formula: UJL= v cos 6 + u s i n 6 (3.1) 23 where v i s the northern component of the current, u i s the eastern component of the current and 6 i s equal to the d i r e c t i o n of the channel. The long channel component of the current was then p l o t t e d over 28 day t i d a l c y c l e s . Cycles were chosen to cover the period from spring t i d e to spring t i d e (maximum t i d a l height to maximum t i d a l height) as determined from hourly water l e v e l predictions received from the Tides and Currents Section, I n s t i t u t e of Oceans Sciences, Sidney, B.C. These predictions were based on data from t i d e gauge data obtained from Chrome Island on the southern end of Denman Island. The 29 m records indicate f o u l i n g a f t e r July 20th, 1986 and therefore data a f t e r t h i s time have not been included. While not a l l data has been shown from a l l the meters, due to f o u l i n g or meter s e r v i c i n g during the chosen spring t i d e to spring t i d e c y c l e , the data presented i n Figures 3.2 to 3.14 are considered a representative sample. 3.22 Meter C o r r e l a t i o n On occasions (Table 3.1) during both flood and ebb t i d e s , the v e l o c i t y of the Marine Advisors current meter was compared to the v e l o c i t y of the Aanderaa current meters. A Model I regression (Sokal and Rohlf, 1981) was performed on these data (Fig. 3.15). The Aanderaa meter was assumed to measure the current v e l o c i t y with a greater accuracy than the Marine Advisors current meter and therefore was chosen Figure 3.2 Long channel current v e l o c i t i e s from March 30 to A p r i l 27, 1986 at Lambert Channel Aanderaa St a t i o n 1. 24 F l o o d 3 1 5 ° 6 0 CO £ o o _o <1> > c <u l_ o LONG CHANNEL CURRENT VELOCITIES LAMBERT 1 M e a n = — 1 . 8 c m . s - 1 4 5 - j - D e p t h = 2 3 m - 6 0 M a r c h 3 0 Ebb 1 3 5 ° Apr i l 13 Apr i l 2 7 Figure 3.3,4 Long channel current v e l o c i t i e s from March to A p r i l 27, 1986 at Lambert Channel Aanderaa Station 2. Flood 3 1 5 ° 6 0 LONG CHANNEL CURRENT VELOCITIES LAMBERT 2 Mean = — 1.60 c m . s ^ 4 5 + D e p t h = 2 9 m CO £ o u _o > c ( J „ 3 0 1 5 - -0 " - 1 5 - 3 0 - 4 5 - 6 0 M a r c h 3 0 Ebb 1 3 5 ° F l o o d 3 1 5 ° 6 0 Apr i l 13 LONG CHANNEL CURRENT VELOCITIES LAMBERT 2 Apr i l 2 7 M e a n = — 1.4 c m . s ^ 4 5 4- D e p t h = 4 2 m £ o ' u _o > c cu -- 6 0 M a r c h 3 0 Ebb 1 3 5 ° Apr i l 13 Apr i l 2 7 Figure 3.5,6 Long channel current v e l o c i t i e s from May 25 June 22, 1986 at Lambert Channel Aanderaa Station 2. Flood 3 1 5 ° 6 0 LONG CHANNEL CURRENT VELOCITIES LAMBERT 2 CO E o o o cu > c CD D o Mean = — 4 . 9 c m . s - 1 D e p t h = 2 9 m o CD > c CD t_ i_ o - 6 0 May 2 5 Ebb 1 3 5 ° F lood 3 1 5 c 60' 4 5 -3 0 -15 J u n e 8 LONG CHANNEL CURRENT VELOCITIES LAMBERT 2 J u n e 2 2 •60 M e a n = — 1.6 c m . s 1 D e p t h = 4 2 m May 2 5 Ebb 1 3 5 ° J u n e 8 J u n e 2 2 Figure 3.7,8 Long channel current v e l o c i t i e s from June 22 to July 20, 1986 at Lambert Channel Aanderaa Station 2. F lood 3 1 5 ° . 6 0 LONG CHANNEL CURRENT VELOCITIES LAMBERT 2 M e a n = - 6 . 4 c m . s - 1 | D e p t h = 2 9 m July 2 0 E o o _o cu > c <p L_ i _ 3 o F l o o d 3 1 5 ° 6 0 4 5 + | 3 0 15 0 - 1 5 - 3 0 -45-- 6 0 J u n e 2 2 LONG CHANNEL CURRENT VELOCITIES LAMBERT 2 M e a n = — 1.9 c m . s - 1 :Depth = 4 2 m July 6 Ju ly 2 0 Ebb 1 3 5 ° 28 Flood 3 1 5 ° 6 0 LONG CHANNEL CURRENT VELOCITIES LAMBERT 2 Mean = - 0 . 8 c m . s 1 4 5 - D e p t h = 4 2 m CO E o ' o o CD > C CD i -i _ 3 o - 6 0 4 J u l y 2 0 Ebb 1 3 5 ° Flood 3 1 5 ° Aug 3 LONG CHANNEL CURRENT VELOCITIES LAMBERT 3 A u g 17 7 5 a n \ M e a n = - 0 . 5 c m . s - 1 b U + D e p t h = 4 2 m E o o o CD > c <D i _ i _ 3 o - 7 5 Ju l y 2 0 Ebb 1 3 5 ° A u g u s t 3 A u g u s t 17 Figure 3.11,12 Long channel current v e l o c i t i e s from May 2 to June 22, 1986 at Lambert Channel Aanderaa Station 3. Flood 3 1 5 ° 7 5 6 0 LONG CHANNEL CURRENT VELOCITIES LAMBERT 3 o o o > c 3 o Mean = — 1.9 c m . s 1 D e p t h = 2 9 m - 7 5 V May 2 5 Ebb 1 3 5 ° Flood 3 1 5 ° J u n e 8 LONG CHANNEL CURRENT VELOCITIES LAMBERT 3 J u n e 2 2 J u n e 2 2 Figure 3.13,14 Long channel current v e l o c i t i e s from June to July 20, 1986 at Lambert Channel Aanderaa Station 3. F l o o d 3 1 5 ° 7 5 LONG CHANNEL CURRENT VELOCITIES LAMBERT 3 M e a n = - 2 . 2 c m . s 1 D e p t h = 2 9 m Ju ly 20 Flood 31 5 ° 7 5 LONG CHANNEL CURRENT VELOCITIES LAMBERT 3 M e a n = - 4 . 0 c m . s D e p t h = 4 2 m •1 Ju ly 2 0 F i g u r e 3.15 Model I r e g r e s s i o n of Aanderaa c u r r e n t meter da t a vs the Marine A d v i s o r s c u r r e n t d a t a a t the same times and depths. CURRENT METER REGRESSION A a n d e r r a Ve loc i ty ( c m . s ^ ) 32 as the independent v a r i a b l e . A c o r r e l a t i o n c o e f f i c i e n t of 0.915 (S.E.=2.66, n=18) and a y intercept of -1.374 cm.s"1 were obtained. The regression was s i g n i f i c a n t with an r of 0.838, p<0.001. As the Aanderaa current meters were deemed to be more representative of actual current v e l o c i t i e s than the deck readout Marine Advisors surface operated current meter, data from the Marine Advisors surface operated current meter was then scaled to the Aanderaa values. Scaling was c a r r i e d out by determining the proposed v e l o c i t y of the Marine Advisors meter from the e x i s t i n g Aanderaa value at 29 and 42 m using the formula; yj_ = -1.374 cm.s - 1 + 1.002Xi cm.s - 1 (3.2) determined from the Model 1 regression. Where y^ i s the Marine Advisors surface operated meter v e l o c i t y at depth i , and i s the Aanderaa meter v e l o c i t y at depth i . As two Aanderaa v e l o c i t i e s were av a i l a b l e for any one v e r t i c a l p r o f i l e with the Marine Advisors surface operated meter, v a r i a t i o n s of the surface meter v e l o c i t i e s from those predicted u t i l i z i n g the Aanderaa v e l o c i t i e s and formula 3.2 were determined. The mean of the two v a r i a t i o n s from Aanderaa v e l o c i t i e s was then u t i l i z e d to correct the v e r t i c a l p r o f i l e to the Aanderaa readings. 3.23 Current P r o f i l e s In order to determine the c h a r a c t e r i s t i c s of the v e l o c i t y over the water column, v e r t i c a l v e l o c i t y p r o f i l e s (date, time and t i d a l condition l i s t e d i n Table 3.1) were performed u t i l i z i n g the Marine Advisors Inc. Savonius rotor current meter downstream of the moored Aanderaa meters. V e r t i c a l p r o f i l e s performed downstream of Aanderaa s t a t i o n 2 were u t i l i z e d to compose a mean v e l o c i t y p r o f i l e . Station 2 was u t i l i z e d as i t was closest to the mixing s i t e . Only ebb t i d e p r o f i l e s were u t i l i z e d as mixing was never observed during f l o o d t i d e s , possibly due to the e f f e c t s of topographic features south of the s p i t . In order to obtain a mean current p r o f i l e , s i x v e l o c i t y p r o f i l e s obtained during ebb t i d e s were standardized to one v e l o c i t y at a depth of 35 m (35 m depth was approximately the intermediate depth between the two moored Aanderaa meters deployed at s t a t i o n 2). Standardization was performed by eithe r m u l t i p l y i n g or Table 3.1 V e r t i c a l Current P r o f i l e Data Date(Stn) Time Aanderaa Marine Adv. Tide Depth (Hours) (cm. Di r e c t i o n (Meters) 03/19(1) 1409 9.8 7.2 Ebb 23 03/19(1) 1509 10.7 8.7 Ebb 23 03/19(1) 1540 9.3 9.2 Ebb 23 03/19(2 ) 1636 8.2 7.2 Ebb 29 03/19(2) 1641 7.6 5.1 Ebb 42 03/19(2) 1708 7.3 7.2 Ebb 42 03/19(2) 1712 7.8 7.7 Ebb 29 03/19(2) 1807 7.0 5.1 Ebb 29 03/19(2) 1810 7.0 4.6 Ebb 42 03/19(2) 1826 6.9 2.6 Ebb 42 03/19(2) 1830 9.1 8.7 Ebb 29 05/14(2 ) 0832 22.1 27.8 Ebb 29 05/14(2) 1002 13.8 7.1 Ebb 42 05/14(2) 1010 25.3 21.3 Ebb 29 05/19(2) 2045 4.8 3.8 Flood 29 05/19(2) 2050 2.5 3.1 Flood 42 05/19(2) 2124 2.3 3.0 Flood 42 05/19(2) 2139 3.1 2.0 Flood 29 34 Figure 3.16 Mean current v e l o c i t y required to induce mixing on an ebb t i d e i n Lambert Channel, the S t r a i t of Georgia. Error bars denote 1 standard error. 0 0 0 2 2 0 MEAN CURRENT PROFILE INDUCING MIXING Ve loc i t y ( c m . s - ^ ) 1 0 15 2 0 2 5 3 0 3 5 CL CD Q 3 0 4 0 -M e t e r Meter_ . Mean C u r r e n t V e l o c i t y For The W a t e r C o l u m n = 1 1.6 c m . s - 1 5 0 35 d i v i d i n g the v e l o c i t y obtained at 35 m to force i t to a v e l o c i t y of 10.5 cm.s - 1 with the rest of the v e l o c i t i e s obtained i n the p r o f i l e also being transformed by the same amount. The value 10.5 cm.s - 1 was chosen because i t was the mean value when mixing events were observed (Section 3.24). Figure 3.16 gives the shape of the mean current v e l o c i t y vs depth upon commencement of mixing at Aanderaa Station 2 during ebb t i d e s . 3.24 Mixing V e l o c i t y Mixing plumes were observed (increased s a l i n i t i e s and decreased temperatures as measured by STD at 1 m depth) to commence on f i v e occasions i n 1986 (Table 3.2). In order to get the mean current v e l o c i t y at commencement of mixing, the current v e l o c i t y obtained at the time c l o s e s t to the onset of mixing was determined from the Aanderaa record at Stn. 2. The v e l o c i t i e s 20 min p r i o r to the mixing observations and 20 min a f t e r the mixing observations were also obtained and the mean current v e l o c i t y of these three times determined. The sum of meters at 29 m and 42 m at any one time divided by 2 gives the mean v e l o c i t y at that time at the intermediate depth of 35 m (assumes a l i n e a r decrease i n current v e l o c i t y between the two meters). The sum of the three times (20 min p r i o r , 20 min a f t e r and the time c l o s e s t to the mixing time) divided by 3 gives the mean current v e l o c i t y at 35 m at the time of mixing. The mean ebb t i d e v e l o c i t y c a l c u l a t e d by the above method during the 5 36 observed commencements of mixing was 10.5 cm.s - with a standard error of 1.5 cm.s-''" (n=5). Table 3.2 Current v e l o c i t i e s from Aanderaa meters at Station 2 at commencement of mixing. Date Time 1 Time 2 Time 3 Mixing Time Depth ("mixing [ ± 20 minutes) meters 06/18/86 11.8 16.3 17.1 0722 29 06/18/86 2.6 4.2 4.5 0722 42 06/21/86 11.5 11.5 16.6 1031 29 06/21/86 8.2 12.9 28.9 1031 42 06/23/86 9.6 10.1 12.4 0300 29 06/23/86 11.8 11.5 13.2 0300 42 07/10/86 9.6 10.1 11.2 0745 29 07/10/86 3.7 3.1 5.4 0745 42 07/11/86 8.2 10.1 12.4 0820 29 07/11/86 6.8 7.9 8.2 0820 42 Mean current speed at 29 m for mixing = 12.2 cm.s , S.E.=0.8 Mean current speed at 42 m for mixing = 8.9 cm.s , S.E.=2.2 In order to determine the extent of mixing during June and July 1986, the time that the current v e l o c i t y exceeded 10.5 cm.s - 1 on ebb tides at Lambert Aanderaa mooring 2 was determined. Figure 3.17 gives the mixing time per day f o r the months of June and July 1986 as well as the t o t a l time for mixing to occur during the two months. 3.25 Horizontal Mapping Mapping of s a l i n i t y and temperature v a r i a t i o n s was performed by towing an InterOcean CSTD at a depth of 1 m Figure 3.17 Hours per day when mixing conditions e x i s t Lambert Channel as well as t o t a l mixing during June and July, 1986 (Ebb v e l o c i t i e s exceeding 10.5 cm.s - 1, S.E.=1.5cm.s n=5) PERIOD OF MIXING CONDITIONS J u n e a n d Ju ly , 1 9 8 6 Days 38 beside the ship with s a l i n i t y v a r i a t i o n s logged on a personal computer at 5 s i n t e r v a l s , as well as manually when s a l i n i t y v a r i e d by 0.2 ppt, with p o s i t i o n logged manually at the same time. Positions i n the channel were determined through u t i l i z a t i o n of a Furuno Model LC Loran C, which allowed r e p l i c a t i o n of p o s i t i o n to within 10 m. The vessel was held at approximately a constant v e l o c i t y through the water of about 2 m.s - 1. Diagonal transects across the channel following a preset course (Fig. 3.18) were performed allowing s a l i n i t y v a r i a t i o n s to be p l o t t e d i n the channel. Transects were a l t e r e d when deemed necessary to elucidate surface s a l i n i t y v a r i a t i o n s . These deviations from the preset courses are indicated on a f f e c t e d h o r i z o n t a l s a l i n i t y maps. Figures 3.19 to 3.27 are i n d i c a t i v e of surface s a l i n i t y d i s t r i b u t i o n s observed i n the region surrounding Shingle S p i t . Figure 3.19 demonstrates that mixing i s not occurring south of Shingle Spit during a period of high f l o o d v e l o c i t y (31.8 cm.s - 1) while figures 3.20 and 3.22 i n d i c a t e that at low ebb v e l o c i t i e s mixing was not evident o f f Shingle S p i t . Figures 3.21, 23, 24, 25, 26 and 27 are i n d i c a t i v e of mixing, as increased surface s a l i n i t i e s compared to the rest of the channel are observed. Figure 3.2 7 shows a mixing event when v e l o c i t i e s are below the proposed mixing v e l o c i t y but within the range of error c a l c u l a t e d . Surface mapping, i n a narrow channel with high flow rates makes the actual determination of s a l i n i t y d i s t r i b u t i o n s d i f f i c u l t as mixing Figure 3.18 Predetermined horizontal mapping course, i n Lambert Channel. Scales represent time d i f f e r e n t i a l s from Loran C sending stations. 41950 41955 41960 40 Figure 3.19 Surface map of s a l i n i t y on June 18, 1986 during flo o d t i d e , maximum v e l o c i t y during sampling period (1320 to 1530 P a c i f i c Daylight Time) from Aanderaa meters (Mean v e l o c i t y from 2 meters at Stn. 2) 31.8 cm.s" 1. No mixing evident. S a l i n i t i e s between contour l i n e s are as marked, + 0.1 ppt. Scale 1:20,000 41 Figure 3.20 Surface map of s a l i n i t y on June 19, 1986 during ebb t i d e , maximum v e l o c i t y during sampling period (0651 to 0954 P a c i f i c Daylight Time) from Aanderaa meters (Mean v e l o c i t y from 2 meters at Stn. 2) 6.20 cm.s - 1. No mixing evident. S a l i n i t i e s between contour l i n e s are as marked + 0.1 ppt. Scale 1:20,000 42 Figure 3.21 Surface map of s a l i n i t y on June 20, 1986 during ebb t i d e , maximum v e l o c i t y during sampling period (1145 to 124 3 P a c i f i c Daylight Time) from Aanderaa meters (Mean v e l o c i t y from 2 meters at Stn. 2) 17.6 cm.s . Mixing evident southwest of Shingle S p i t , Core s a l i n i t y 27.5 ppt with surrounding water mass of 26.5 ppt. Dashed l i n e with arrows represents ships track. S a l i n i t i e s between contour l i n e s are as marked + 0.1 ppt. Scale 1:5,000 \=100 m 43 Figure 3.22 Surface map of s a l i n i t y on June 21, 1986 during ebb t i d e , maximum v e l o c i t y during sampling period (0745 to 0948 P a c i f i c Daylight Time) from Aanderaa meters (Mean v e l o c i t y from 2 meters at Stn. 2) 6.45 cm.s" 1. No mixing evident. S a l i n i t i e s between contour l i n e s are as marked + 0.1 ppt. Scale 1:20,000 44 Figure 3.23 Surface map of s a l i n i t y on June 21, 1986 during ebb t i d e , maximum v e l o c i t y during sampling period (0808 to 0833 P a c i f i c Daylight Time) from Aanderaa meters (Mean v e l o c i t y from 2 meters at Stn. 2) 11.80 cm.s . Mixing evident southwest of Shingle Spit core of 27.3 ppt with surrounding water of 26.5 ppt. Dashed l i n e represents ships track. S a l i n i t i e s between contour l i n e s are as marked + 0.1 ppt. Scale 1:5,000 Shingle Spit 45 Figure 3.24 Surface map of s a l i n i t y on June 22, 1986 during ebb t i d e , maximum v e l o c i t y during sampling period (0815 to 104 9 P a c i f i c Daylight Time) from Aanderaa meters (Mean v e l o c i t y from 2 meters at Stn. 2) 11.25 cm.s - 1. Two mixing events evident southwest of Shingle S p i t both with centers with s a l i n i t i e s of 27.3 ppt. S a l i n i t i e s between contour l i n e s are as marked +0.1 ppt. Scale 1:20,000 Figure 3.25 Expanded surface map of s a l i n i t y on June 22, 1986 during ebb t i d e , maximum v e l o c i t y during sampling period (0815 to 104 9 P a c i f i c Daylight Time)from Aanderaa meters (Mean v e l o c i t y from 2 meters at Stn. 2) 11.25 cm.s S a l i n i t i e s between contour l i n e s are as marked + 0.1 ppt. Scale 1:5,000 26.0 47 Figure 3.26 Surface map of s a l i n i t y on June 24, 1986 during ebb t i d e , maximum v e l o c i t y during sampling period (0930 to 1100 P a c i f i c Daylight Time) from Aanderaa meters (Mean v e l o c i t y from 2 meters at Stn. 2) 10.5 cm.s - 1. Mixing evident southwest of shingle Spit center with s a l i n i t y of 26.3 ppt. S a l i n i t i e s between contour l i n e s are as marked + 0.1 ppt. Scale 1:20,000 23.5 25.0 H =100 m 48 Figure 3.27 Surface map of s a l i n i t y on June 24, 1986 during ebb t i d e , maximum v e l o c i t y during sampling period (1200 to 1255 P a c i f i c Daylight Time) from Aanderaa meters (Mean v e l o c i t y from 2 meters at Stn. 2) 9.55 cm.s . Mixing evident south of Shingle Spit core s a l i n i t y of 25.7 ppt. S a l i n i t i e s between contour l i n e s are as marked + 0.1 ppt. Scale 1:20,000 49 e v e n t s may be a d v e c t e d p a s t so r a p i d l y t h a t d e t e c t i o n i s i m p o s s i b l e . The shape o f t h e m i x i n g e v e n t s i s assumed, due t o l a c k o f r e s o l u t i o n t o be a p p r o x i m a t e l y c i r c u l a r due t o t h e c h a r a c t e r i s t i c s o b s e r v e d a t t h e m i x i n g g e n e r a t i o n s i t e and maps when i n d i v i d u a l e v e n t s were w e l l sampled such as F i g u r e s 3.21 and 3.23. 3.26 A e r i a l P h o t o g r a p h y A e r i a l p h o t o g r a p h s were o b t a i n e d from t h e Department o f E n v i r o n m e n t , B r i t i s h C o l u m b i a . These p i c t u r e s were t a k e n a t an a l t i t u d e o f between 4800 and 5500 m d u r i n g f l i g h t s s u r v e y i n g t h e i n t e r t i d a l r e g i o n s o f t h e S t r a i t o f G e o r g i a . T a b l e 3.3 g i v e s t h e d a t e s and t i m e s o f f l i g h t s when plumes were e v i d e n t s o u t h o f S h i n g l e S p i t , w i t h examples o f plumes shown i n F i g s . 3.2 8 t o 3.30. T a b l e 3.3 A e r i a l p h o t o g r a p h s o v e r S h i n g l e S p i t d e m o n s t r a t i n g m i x i n g c h a r a c t e r i s t i c s Date Time H i g h T i d e Low ' T i d e P h o t o g r a p h Time H e i g h t Time H e i g h t 07/01/1972 1320 0845 3.8 m 1525 1.4 m 07/01/1972 1325 tf i l i l II 07/26/1975 0919 0743 3.8 m 1423 1.6 m 07/26/1975 1107 i l II fi II 07/26/1975 1135 II if l i II 08/01/1980 1320 0933 4.0 m 1548 1.7 m D u r i n g b o t h 1986 and 1987 t h e s u r f a c e c h a r a c t e r i s t i c s o f t h e plume were o b s e r v e d t o be s i m i l a r t o t h o s e seen i n t h e a e r i a l p h o t o g r a p h s w i t h t h e predominant forms b e i n g 50 r h ! n n ! i 3 ' ? i 8 . ^ e 5 i a l P 5 o t ° 9 r a P h of mixing event i n Lambert Channel. A l t i t u d e - 16,500 f t . ; Time = 1325; Date - July 1, 51 Figure 3.29 A e r i a l photograph of mixing event i n Lambert Channel. A l t i t u d e - 19,000 f t . ; Time = 1135; Date = July 26, 1975 1975 M 19,000 f t . ; Time - 0920; Date - July 26, 53 Figure 3.31 Interpretation of figure 3.28, a e r i a l photograph of mixing event i n Lambert Channel. A l t i t u d e = 16,500 f t % ; Time = 1325; Date = July 1, 1972 Downsteam mixing plume | 1 = 100 m 54 F i g u r e 3.32 I n t e r p r e t a t i o n of f i g u r e 3.29, a e r i a l photograph of m ixing event i n Lambert Channel. A l t i t u d e = 19,000 f t . ; Time = 1135; Date = J u l y 26, 1975 | 1 =100 m 55 Figure 3.33 In t e r p r t a t i o n of figure 3.30, a e r i a l photograph of mixing event i n Lambert Channel. A l t i t u d e = 19,000 f t . ; Time = 0920; Date = July 26, 1975 H =100 m 56 those seen i n figures 3.28 and 3.29. Figure 3.29 i s t y p i c a l of surface c h a r a c t e r i s t i c s at the onset of mixing, while figure 3.28 i s t y p i c a l of the general form of the mixing event. Figure 3.30 appears to be smeared due to wind e f f e c t s . Wind i s presumed to be the cause due to the more pronounced waves i n t h i s photograph. 3.27 V e r t i c a l S a l i n i t y and Temperature P r o f i l e s V e r t i c a l p r o f i l e s of s a l i n i t y and temperature were performed i n the region of the mixing generation s i t e and i n the stable water column i n Lambert Channel i n 1986 and 1987 (Figures 3.34-37). Figures 3.34 and 3.35 demonstrate that colder more s a l i n e deep water i s being moved above the pycnocline e x i s t i n g at approximately 10 m, suggesting that mixing i s taking place. Figures 3.36-37 again show an addition of colder more saline water into the surface layer. Due to equipment problems p r o f i l e s 3.36-37 were taken over an extended period of time r e s u l t i n g i n a high degree of v a r i a t i o n due to the movement of mixed water past the probe. As a hand cable was being u t i l i z e d for these p r o f i l e s , the maximum depth i s 25 m and i t i s assumed that below t h i s depth s a l i n i t y and temperature c h a r a c t e r i s t i c s would have been s i m i l a r i n the two regions. 3.2 8 Volume Mixed The net volume of water mixed at the mixing i n i t i a t i o n s i t e j ust o f f Shingle s p i t (as determined by a e r i a l Figures 3.34-35 V e r t i c a l p r o f i l e of s a l i n i t y and temperature i n the mixing event . Figure 3.34 i s marked as (A) and was obtained on June 23, 1986, (very l i t t l e mixing evident) while Figure 3.35 marked as (B) was obtained on July 12, 1986.(Dashed l i n e = plume s a l i n i t y ; s o l i d l i n e = stable watermass s a l i n i t y ; dashed l i n e with dots = plume temperature; s o l i d l i n e with dots = stable watermass temperature) VERTICAL PROFILE OF SALINITY AND TEMPERATURE Q. V Q Q 26 Salinity (ppt) 27 28 •+-26 12 14 Temperature (°C) VERTICAL PROFILE OF SALINITY AND TEMPERATURE Salinity (ppt) 27 28 -tr: ' ^ 16 12 14 Temperature (°C) 16 Figures 3.36-37 V e r t i c a l p r o f i l e of s a l i n i t y and temperature i n the mixing event . Figure 3.36 i s marked as (A) and was obtained on June 24, 1987, while Figure 3.37 marked as (B) was obtained on June 25, 1987.(Dashed l i n e = plume s a l i n i t y ; s o l i d l i n e = stable watermass s a l i n i t y ; dashed l i n e with dots = plume temperature; s o l i d l i n e with dots = stable watermass temperature) VERTICAL PROFILES OF SALINITY AND TEMPERATURE SojN-ity (ppt) 24 26 28 30 OH 1 : 1 h 45 -I 1 1 1 1 10 11 12 13 14 15 Temperature (°C) 59 photographs and horizontal STD mapping) can be determined through the c a l c u l a t i o n of the volume of the mixed water mass. The siz e of mixed sections was on the order of 10 m to 15 m i n diameter (at the surface) with a period of formation of approximately 2-3 min. Size was determined by observations of increases i n s a l i n i t y , u t i l i z i n g the InterOcean CSTD as well as v i s u a l observations of surface b o i l s on dates l i s t e d i n Table 3.4. Table 3.4 Observations of period of mixing events by STD and v i s u a l determination.(* denotes v i s u a l observation) Date Time Period S a l i n i t y Increase 06/23/86 0945 ~2 min* 2.7 ppt 06/23/86 1213 ~2 min* 2.5 ppt 06/23/86 1235 ~3 min* 06/24/86 1025 "3 min* 06/16/87 1401 ~2 min* 1.7 ppt 06/23/87 0558 ~3 min* 2.1 ppt 06/24/87 0821 ~3 min* 2.0 ppt 07/11/87 0930 ~2 min* 2.3 ppt 08/07/87 0730 ~3 min* 1.4 ppt Assuming that the mixing event extended from the surface to a depth of 10 to 15 m as shown i n Fi g s . 3.34 to 3.37, and i s c y l i n d r i c a l i n nature extending to the pycnocline as observed by surface c h a r a c t e r i s t i c s and STD p r o f i l e s (Figs. 3.34 to 3.37), the volume of water i n the mixed section can be determined by, V e = n-R2x Z p (3.3) 60 where R i s the radius of the mixed section and Zp i s the depth of the pycnocline. Thus with a mixing depth of 10 to 15 m as observed and a diameter of 10 to 15 m, the volume of o each mixxng event ranges between 800 to 2700 m , with the o average value being 1700 m . The estimate i s conservative as the surface feature observed may not i n d i c a t e the extent of the mixing event but just a section of the perimeter of the mixing event. Examination of the Aanderaa data from June 23, 1986 shows that mixing conditions existed f o r approximately 13 h, giv i n g a p o t e n t i a l of 312 mixing events, assuming events to occur every 2.5 minutes (as observed on June 17, July 12, and August 8, 1987 by surface b o i l s and increased s a l i n i t i e s ) . With the range of volumes given above the t o t a l C O C O mixing volume would be between 2.4x10 m and 8.3x10 m for June 23, 1986. Examination of the Aanderaa current meter record at Aanderaa Stn 2 gives the amount of time, during June and July 1986, that current v e l o c i t i e s for the water column were s u f f i c i e n t for mixing to be 571 h (Figure 3.17). Thus i f the i n t e n s i t y of mixing remains the same, the volume • 7 mixed during June and July, 1986 would vary between 1.1x10 T O -I o and 3.6x10 m with a mean of 2.4x10 m . The estimate does not include possible mixing downstream. Downstream mixing w i l l occur i n the plume created by Shingle Sp i t as long as the v e l o c i t y of the plume i s greater than the v e l o c i t y of the surrounding water mass (Netterville,1985). Entrainment i n the plume w i l l be due to the t r a n s f e r of energy from large eddies to small eddies 61 driven by vortex stretching and leading to the viscous d i s s i p a t i o n of energy near the Kolmogorov microscale scales (Tennekes and Lumley, 1972). Therefore any energy input r e s u l t i n g i n mixing off the end of Shingle Spi t w i l l r e s u l t i n a d i s s i p a t i o n of energy downstream causing downstream mixing. In order to determine the extent of downstream mixing i n t o the surface layers, the distance across the mixed section downstream from the mixing generation s i t e was examined with respect to s a l i n i t y v a r i a t i o n s . Assuming that the depth of the plume remains the same as at the mixing generation s i t e , and that any increase i n volume i s due to downstream mixing a f t e r the i n i t i a l mixing event (includes i n i t i a l volume mixed) due to spreading of the plume ( N e t t e r v i l l e , 1985). If we u t i l i z e the maximum distance across the mixed section at the mixing generation s i t e (10 to 15 m) and the depth of pycnocline ("10 m) we obtain a maxxmum mixing volume of between 100 to 150 m at the mixing generation s i t e . Downstream from the mixing s i t e , Figs. 3.21, 23, 24, 25, 26, and 27 reveals that the width of the mixing region increases (cross channel width of the plume increases), evidence of the increase i n mixing volume being a l a r g e r volume of water with s i m i l a r s a l i n i t y c h a r a c t e r i s t i c s i n a surrounding water mass of lower s a l i n i t y . Table 3.5 gives the distance across the mixed section taken during the horizontal mapping as well as current v e l o c i t i e s from the moored Aanderaa meters. The 62 downstream diameter of the mixed water mass as shown i n Table 3.5 ranges from 89 to 440 m with a mean diameter of 234 m. These values w i l l be influenced by degree of s t r a t i f i c a t i o n , surface wind e f f e c t s and current v e l o c i t i e s i n the channel. Horizontal maps obtained encompass the lower current v e l o c i t i e s obtained i n the channel thus i n d i c a t i n g that downstream mixing could be even more sub s t a n t i a l than observed. Therefore a conservative estimate of downstream mixing volume i s from 6 to 44 times the i n i t i a l mixing volume with a mean value of 19, downstream of the mixing generation s i t e (extreme maximum, minimum, and mean given by; 89/15=6; 440/10=44; 234/12.5=18.7). Applying these values to the i n i t i a l mixing volume c a l c u l a t i o n s gives 7 "3 mixing volumes ranging from a low of 6.6x10 m to a high of 1.6x10 m with a mean value of 4.5x10 m f o r the months of June and July, 1986. Table 3.5 Distance across mixed sections, maximum current v e l o c i t i e s from Aanderaa meter record and s a l i n i t i e s i n the various areas. DATE CURRENT DOWNSTREAM SALINITY VARIATIONS (ppt) Time cm.s~1 Width (m) Core Downstream Ambient 06/20/86 10.15 245 27.1 27.3 26.0 0845-0943 06/21/86 27.05 89 27.1 27.2 26.3 0808-0915 06/22/86 9.15 440 27.1 27.1 26.0 0815-1049 06/23/86 12.95 220 25.5 25.7 23.0 0930-1100 06/23/86 23.0 176 25.3 25.7 23.0 1200-1255 Mean distance across downstream section = 234 m 63 3.29 Flow C h a r a c t e r i s t i c s In order to determine the c h a r a c t e r i s t i c s of the flow around Shingle S p i t , the Reynolds number, Re was c a l c u l a t e d : Re =UD/v (3.4) where U i s the unperturbed v e l o c i t y , D the dimension of the body and v (0.014 cm 2.s - 1 Pond and Pickard, 1983) the kinematic v i s c o s i t y . Reynolds number values upon commencement of mixing as well as values f o r the v a r i a b l e s used i n the c a l c u l a t i o n are given i n Table 3.6. The Richardson Number, i s a measurement of the r e l a t i v e importance of the mechanical and density e f f e c t s on the water column s t a b i l i t y . R ± = N 2/(6u/6z) 2 (3.5) where N i s the Brunt-Vaisala frequency, a measure of the o s t a t i c s t a b i l i t y , and (6u/6z) i s the v e l o c i t y shear, while N 2 = -(g/p)(6a t/6z) (3.6) a t = p - 1000 where g i s the a c c e l e r a t i o n of gravity and p i s the density. Richardson Number values as well as the values of the v a r i a b l e s are given i n Table 3.7. The Richardson Number u t i l i z e d here was c a l c u l a t e d from the v e r t i c a l p r o f i l e obtained during July 12, 1986 i n the stable water column ( F i g . 3.35) and current v e l o c i t i e s u t i l i z e d were those c a l c u l a t e d as the minimum required to induce mixing (Fig. 3.16). The v e r t i c a l s a l i n i t y and temperature p r o f i l e on July 12, 1986 was chosen as i t represented the highest degree of s t r a t i f i c a t i o n when mixing was observed to be occurring. V a r i a t i o n s i n s a l i n i t y and temperature vs depth i n the stable and mixed water column are given i n F i g s . 3.34 to 3.37. Table 3.6 Reynolds number c a l c u l a t i o n and v a r i a b l e s used i n i t s c a l c u l a t i o n . Flow v e l o c i t y (U) 11.6 cm.s-1 (Velocity of Observed Mixing) Dimension of Body (D) 5.0x10 cm (Length of Shingle Spit) Kinematic V i s c o s i t y (v) 0.014cm . s - 1 Reynolds Number (Re) 4.1xl0 6 (Re=UD/v) Table 3.7 Richardson Number variables and c a l c u l a t i o n s . Brunt-Vaisala Frequency (N—) 0 to 10.5 m 3.57x10 3 radians.s * 30 to 40 m 3.09xl0~ 4 r a d i a n s . s - 1 Surface to 10.5 m Density change Depth Change Current V e l o c i t y Change Richardson No. (Ri) 30 m to 40 m Density Change Depth Change Current V e l o c i t y Change (30 m to 40 m) Richardson No. (Ri) (6p) 3.91 kg.m - 3 (6z) 10.5 m (6u) 15 cm.s 17.5 (6p') 0.322 kg.m - 3 (6z') 10 m (6u') 5 cm.s 12.4 The Reynold's number obtained of 4.1x10 for flow i n the Lambert Channel at the onset of mixing conditions indicates that the flow has the p o t e n t i a l to be turbulent during these times. Calculations of the Richardson Number i n the center Channel indicate the existence of a stable water column. Mixing should not commence i n the Channel away from the Spit as Richardson values are greater than 1 the required-value f o r i n s t a b i l i t y . The presence of protrusion i n t o a flow causes an increase i n v e l o c i t y o f f the edge of the protrusion (Abramovich, 1963; Batchelor, 1967). Thus i n Lambert Channel o f f Shingle Spit an increase i n v e l o c i t y i s created r e s u l t i n g i n greater shear i n the region of the Sp i t . The increase i n shear o f f the Spit i s s u f f i c i e n t to reduce the s t a b i l i t y of the water column and allow mixing to occur. Determinations of current v e l o c i t i e s and shear i n the region of the Sp i t , where the mixing i s occurring would elucidate the actual conditions r e s u l t i n g i n the mixing at that s i t e . 3.3 Discussion The occurrence of t i d a l l y generated mixing events around s p i t s or promontories i s a commonly observed phenomenon i n coast a l regions. The ephemeral nature, small scales and complexity of the physical phenomena involved have impeded studies on the i n t e r a c t i o n of the phy s i c a l processes and the resultant b i o l o g i c a l production of these events. The mixing event, occurring on ebb t i d e s o f f Shingle Sp i t , has been shown to cause mixing of higher s a l i n i t y , deep water in t o the surface layers i n Lambert Channel. Abramovich (1963) determined that protrusion of an obstacle int o a flow f a c i l i t a t e s an increase of flow v e l o c i t y near a protrusion. I t would seem that increased flow v e l o c i t y caused by the protrusion of Shingle Spit induces s u f f i c i e n t shear to reduce the s t a b i l i t y of the water column s u f f i c i e n t l y f o r mixing to occur. The approximate volume of water experiencing mixing i s i n the range of f i n e - s c a l e processes (meters to hundreds of meters) described by Haury et a l . (1978). Indivi d u a l mixing events should have an e f f e c t on the patchy d i s t r i b u t i o n of planktonic organisms e x i s t i n g o f f Shingle Spit, with implications downstream i f nutrients are added due to the addition of nutrient r i c h deep water. Volumes mixed at any one time w i l l be dependant on the i n t e r a c t i o n of some of the physical factors described here as well as others which have not been addressed such as winds, v a r i a t i o n s i n the s t a b i l i t y of the water column as well as the actual shape of i n d i v i d u a l mixing events and v a r i a t i o n s i n the current shear. Determination of the e f f e c t s of these v a r i a b l e s would enable a more pre c i s e estimation of the implications of flow around Shingle Spi t on the s t a b i l i t y of the water column. Unfortunately due to the scope of t h i s study, time, and equipment l i m i t a t i o n s e l u c i d a t i o n of the e f f e c t s of these v a r i a b l e s was not p o s s i b l e . 68 CHAPTER 4  BIOLOGICAL OCEANOGRAPHY LOCALIZED EFFECTS 4.1 Introduction The i n t e r a c t i o n of physical and b i o l o g i c a l phenomena ul t i m a t e l y determines the routes of nitrogen supply to primary producers i n most marine environments. The a v a i l a b i l i t y of nitrogen i s widely accepted as the nutrient l i k e l y to l i m i t primary production i n the oceans (Ryther and Dunstan, 1971; McCarthy and Carpenter, 1983). Patchy d i s t r i b u t i o n s of nutrients caused by f i n e - s c a l e p hysical and b i o l o g i c a l phenomena have been hypothesized to give r i s e to v a r i a t i o n s of phytoplankton species composition and d e n s i t i e s i n the ocean (Turpin and Harrison, 1979). The purpose of t h i s chapter w i l l be to examine the e f f e c t s of the mixing event o f f Shingle Spit on the f i n e -scale d i s t r i b u t i o n and production of planktonic organisms i n the water mixed o f f Shingle S p i t . The concentrations of n i t r a t e + n i t r i t e , and phosphate w i l l be determined i n i n d i v i d u a l mixing events and compared to the concentrations i n the water mass unaffected by mixing. Phytoplankton contained i n the mixed water w i l l be monitored u t i l i z i n g 1 4 C techniques to determine i f there i s an increase i n the net production over unmixed surface samples. Net production i n the stable water mass w i l l be comparable above the n u t r i e o c l i n e , i f nutrients have been depleted by 69 autotrophes, unless nutrient additions have occurred (excludes d i n o f l a g e l l a t e v e r t i c a l migration). Determination of the increase i n net production i n the mixed water w i l l enable an estimate of the e f f e c t s of the mixing events on t o t a l primary production i n the area. Values obtained i n t h i s study w i l l be compared to t h e o r e t i c a l increases i n production based on the stochiometric Redfield r a t i o (Redfield, 1958). In order to determine the e f f e c t s of the mixing events on zooplankton, point samples i n upwelling events w i l l be obtained and the d e n s i t i e s examined to see i f the mixing events e f f e c t the d i s t r i b u t i o n of these organisms. Estimation of the e f f e c t s of f i n e - s c a l e perturbations of the nutrient regime due to turbulent plumes are presently lacking i n the marine environment primary due to the high degree of v a r i a b i l i t y associated with these events and the inherent sampling problems. Physical mechanisms such as Langmuir c i r c u l a t i o n s (Langmuir, 1938) and i n t e r n a l waves (Herman and Denman, 1979) have been u t i l i z e d to explain patchiness i n nutrient concentrations as well as patchy plankton d i s t r i b u t i o n s i n the marine environment. Although actual t e s t i n g of nutrient concentrations has not been performed. This study w i l l attempt to examine the e f f e c t s of mixing o f f Shingle Spit on the f i n e - s c a l e d i s t r i b u t i o n of planktonic organisms involved. 70 4.2 M e t h o d s a n d R e s u l t s D e t e r m i n a t i o n o f t h e m i x i n g l o c a t i o n was p e r f o r m e d u t i l i z i n g a n I n t e r O c e a n CSTD. I n i t i a l l y a h o r i z o n t a l t r a n s e c t was p e r f o r m e d a t a d e p t h o f 1 m t o d e t e r m i n e t h e s a l i n i t y a n d t e m p e r a t u r e c h a r a c t e r i s t i c s o f t h e r e g i o n . The v e s s e l was a n c h o r e d i n t h e r e g i o n o f m i x i n g a s d e t e r m i n e d by i n c r e a s e d s a l i n i t i e s a n d d e c r e a s e d t e m p e r a t u r e s a s c o m p a r e d t o t h e s u r r o u n d i n g r e g i o n . S a m p l e s f o r n u t r i e n t s , p r i m a r y p r o d u c t i v i t y a n d z o o p l a n k t o n d i s t r i b u t i o n s w e r e o b t a i n e d f r o m 1 m d e p t h f o r b o t h t h e m i x e d a n d s t a b l e r e g i o n s a s d e t e r m i n e d b y s a l i n i t y v a r i a t i o n s . A d e c k - m o u n t e d c e n t r i f u g a l pump ( p o w e r e d by a 5 hp B r i g g s a n d S t r a t t o n e n g i n e ) was u t i l i z e d t o d r a w s a m p l e s t h r o u g h a 10.2 cm I.D. r e i n f o r c e d h o s e . The i n t a k e was e q u i p p e d w i t h a "T" m a n i f o l d t o r e s t r i c t t h e d e p t h o f w a t e r b e i n g s a m p l e d . The i n t a k e o f t h e h o s e was m a i n t a i n e d a t a s p e c i f i c d e p t h a s d e t e r m i n e d by l e n g t h o f c a b l e d e p l o y e d a n d w i r e a n g l e . V o l u m e o f w a t e r f i l t e r e d t h r o u g h a 54 pm mesh p l a n k t o n n e t was a s c e r t a i n e d b y d e t e r m i n i n g t h e t i m e r e q u i r e d t o f i l l a known v o l u m e a n d e x t r a p o l a t i n g t o t h e p e r i o d o f t i m e p e r s a m p l e . Movement o f t h e i n t a k e was r e s t r i c t e d t h r o u g h t h e u s e o f a 35 k g d e p r e s s o r . 4.21 L i g h t D e t e r m i n a t i o n Mean s u r f a c e l i g h t i n t e n s i t y was d e t e r m i n e d w i t h a L i -C o r M o d e l L i - 1 8 5 B l i g h t m e t e r . L i g h t i n t e n s i t i e s i n pE.m" 7 — 1 - . s x w e r e d e t e r m i n e d f r o m 0600 t o 2000 h o u r s , a n d t o t a l s u r f a c e r a d i a t i o n was c a l c u l a t e d . F r o m t h e s e d a t a , i t was determined that samples for radioactive C uptake studies during June, July, and August of 1987 were incubated over 58% (S.E.=5.8%, n=6) of the l i g h t day with a mean irrad i a n c e l e v e l of 3.2 x 10 2 pE.m~ 2.s _ 1 (S.E.= 9.2, n=6). In order to determine the e x t i n c t i o n c o e f f i c i e n t for the water column, Secchi disk depths were obtained during a l l incubation periods. The mean Secchi disk depth during the June sampling period was 6 m, with the mean depth for July and August being 7.5 m. 4.22 Primary Pr o d u c t i v i t y Determination of photosynthetic rate was performed u t i l i z i n g the uptake of radioactive 1 4 C techniques outlined i n Parsons et a l . , (1984). Pumped samples were c o l l e c t e d at a depth of 1 m i n a 10 1 c l e a r p l a s t i c , acid-washed container. Samples were obtained i n the mixed water of the plume, and the unmixed water i n Lambert Channel (as determined by s a l i n i t y and temperature c h a r a c t e r i s t i c s ) , as well as i n the areas north, and south of Lambert Channel. Samples to determine primary pro d u c t i v i t y u t i l i z i n g the 1 4 C method were obtained on June 17, July 12 and August 8, 1987. Samples were f i l t e r e d through 100 /jm Nitex mesh to eliminate large herbivorous zooplankton p r i o r to retention i n c l e a r 10 1 p l a s t i c acid-washed containers ( c o l o n i a l as well as large diatoms would also be eliminated). The containers were held at a depth of 5 m ("20% surface l i g h t l e v e l s as determined by Secchi disk depth, Parsons et a l . , 1979) i n the stable water column for 6 days (thus simulating natural l i g h t and 72 temperature c o n d i t i o n s ) . Samples were o b t a i n e d d u r i n g d a y l i g h t on the f i r s t day and no i n c u b a t i o n s were done on day 1 a f t e r o b t a i n i n g the samples (sample a q u i s i t i o n o c c u r r e d d u r i n g the predetermined i n c u b a t i o n p e r i o d ) . Samples were h e l d a t a depth of 5 m i n the absence of l i g h t u n t i l day 2 when i n c u b a t i o n s commenced. Subsamples were removed d a i l y s t a r t i n g at day two. BOD b o t t l e s (300 ml) were f i l l e d from each sample d a i l y and i n o c u l a t e d w i t h 5 JJCU of H^^CO^ 2 -. These samples were h e l d a t a l i g h t i n t e n s i t y of a p p r o x i m a t e l y -30% of s u r f a c e l i g h t i n t e n s i t y v i a s c r e e n i n g f o r 4 h from 1000 t o 1400 h each day. A f t e r the i n c u b a t i o n the samples were f i l t e r e d through a 0.45 /jm HA M i l l i p o r e f i l t e r (< 100 mm Hg f i l t r a t i o n p r e s s u r e ) f o l l o w i n g the procedure o u t l i n e d by Parsons et a l . , (1984). The f i l t e r s were p l a c e d i n s c i n t i l l a t i o n v i a l s and a c i d i f i e d w i t h 3 drops of 0.5 N HC1 f o r 1 h t o remove u n i n c o r p o r a t e d r a d i o a c t i v e i n o r g a n i c carbon. The f i l t e r s were then d i s s o l v e d i n 10 ml of "Aquasol". R a d i o a c t i v i t y as cpm was determined f o r each v i a l i n a Isocap 300 s c i n t i l l a t i o n c o u n t e r and c o r r e c t e d t o dpm u s i n g a s t a n d a r d 1 4 C source, and a quench curve based on the c h a n n e l s - r a t i o method. Zero-time b l a n k s were used t o c o r r e c t f o r b o t t l e a b s o r p t i o n of 1 4 C . T o t a l 1 4 C a c t i v i t y of the stock s o l u t i o n was determined by adding 20-25 pi H 1 4C03_ stock s o l u t i o n (nominal a c t i v i t y 0.4-0.5 JJCL .ml-"'") t o s c i n t i l a t i o n v i a l s c o n t a i n i n g 0.2 mL phenethylamine, and then adding 10 mL of s c i n t i l l a t i o n f l u o r ( I v e r s o n e t a l . 1976). Carbon uptake c a l c u l a t i o n s were 73 performed u t i l i z i n g the dark b o t t l e technique outlined i n Parsons et a l . , (1984). Total carbon dioxide was determined using the technique described by Parsons et a l . (1984). Primary production was then c a l c u l a t e d per l i g h t day (0600 to 2000 hr s ) . Mean carbon uptake per l i g h t day was compared between the mixing and stable water samples using a Student's t - t e s t and a l e v e l of s i g n i f i c a n c e of 0.05 (Sokal and Rohlf, 1981). Since one of the assumptions of the t - t e s t i s that the means of the mixed and stable samples have equal variances a preliminary F-test was performed. If the F-test proved severe deviations from the equality of variance assumption, the Mann-Whitney U t e s t (nonparametric test) was used instead of the t - t e s t . As one mixed sample from August was l o s t , a Student's t - t e s t and a l e v e l of s i g n i f i c a n c e of 0.05 f o r comparison of a single sample with a mean of a population was performed on the primary production for August (Sokal and Rohlf, 1981). Table 4.1 gives the t - t e s t and Mann-Whitney r e s u l t s of the d a i l y , 5 day t o t a l production, and t o t a l primary production f o r June, July, 1987. Figures 4.1 to 4.3 give net primary production during June, July, and August of 1987. Table 4.2 gives primary production f o r each mixing event as well as mean primary production over the three sampling periods (June, July, and August). Nutrient concentrations as well as s a l i n i t y and temperature at time of c o l l e c t i o n (Day 1) for the various samples are also given i n Table 4.3. 74 H Q: mean primary p r o d u c t i o n i n the mixed water samples equ a l s mean prim a r y p r o d u c t i o n i n the unmixed samples. H a: mean primary p r o d u c t i o n i n mixed water samples does not equal mean prim a r y p r o d u c t i o n i n the unmixed samples. H Q: primary p r o d u c t i o n i n mixed sample belongs t o the p o p u l a t i o n d e f i n e d by the mean primary p r o d u c t i o n i n the unmixed samples. H a: primary p r o d u c t i o n i n the mixed sample belongs t o the p o p u l a t i o n d e f i n e d by the mean primary p r o d u c t i o n i n the unmixed samples. 75 Table 4.1 T-test and Mann-Whitney r e s u l t s of primary p r o d u c t i v i t y t e s t s for June, July, and August 1987. Period T t e s t T c r i t Accept H Q or or or u t e s t U c r i t Reject H Q June Day 2 15 15 Reject* Day 3 14.92 2.365 Reject Day 4 15 15 Reject* Day 5 13 15 Accept* Day 6 3.462 2.365 Reject Total June Days 1-3 10.686 2.365 Reject Days 1-5 18.604 2.365 Reject July Day 2 12 15 Accept* Day 3 8.540 2.365 Reject Day 4 12 15 Accept* Day 5 0.597 2.365 Accept* Day 6 12 15 Accept* Total July Days 1-3 12 15 Accept* Days 1-5 12 15 Accept* Total June-July 13.223 2. 179 Reject Auqust Day 2 2 .447 0.574 Accept$ Day 3 2.447 3.954 Reject$ Day 4 2 .447 3.204 Reject$ Day 5 2.447 0.331 Accept$ Day 6 2.447 2.511 Reject$ Total Auaust Days 1-3 2.447 9.47 Reject Days 1-5 2.447 4.76 Reject Total July-Auqust Days 1-3 2. 160 4.94 Reject Days 3-5 2 . 160 4.95 Reject To t a l June-August Days 1-3 114 170 Reject* Days 1-5 2.08 8.72 Reject * Mann-Whitney t e s t used $ Single specimen compared with a sample gure 4.1 Primary production as determined by radioactive C uptake for incubated water samples during June, 1987. UP denotes i n d i v i d u a l mixed water mass samples obtained at the mixing s i t e while ST denotes the mean of 5 samples taken from the unmixed regions north, south and i n the center of Lambert Channel. Error bars on stable samples (below detection) indicate one standard e r r o r . PRIMARY PRODUCTION PER DAY Mixed vs S tab le 1 2 3 4 5 Days gure 4.2 Primary production as determined by radioa c t i v e C uptake for incubated water samples during July 1987. UP denotes i n d i v i d u a l mixed water mass samples obtained at the mixing s i t e while ST denotes the mean of 6 samples taken from the unmixed regions north, south and i n the center of Lambert Channel. Error bars on stable samples (below detection) denote one standard error. PRIMARY PRODUCTION PER DAY Mixed vs Stab le Days gure 4.3 Primary production as determined by radioactive C uptake for incubated water samples during August, 1987. UP denotes i n d i v i d u a l mixed water mass samples obtained at the mixing s i t e while ST denotes the mean of 6 samples taken from unmixed regions north, south and i n the center of Lambert Channel. Error bars on stable samples denote one standard e r r o r . PRIMARY PRODUCTION PER DAY Mixed vs Stab le Days 79 Table 4.2 Net primary production for each mixing event and mean primary production over the three sampling periods (days 1-3) as determined by radioactive C uptake. NET PRIMARY PRODUCTION S.E. mgC.m during f i r s t 3 days of incubations June Mixed 1 19.7 Mixed 2 24.7 Mixed 3 17.4 Stable (mean) 1.9 0.5 (n=5) July Mixed 1 10.4 Mixed 2 18.2 Stable (mean) 2.4 0.35 (n=6) August Mixed 11.1 Stable (mean) 4.2 0.96 (n=6) T o t a l Production Mixed (mean) 16.9 2.03 (n=6) Stable (mean) 3.1 0.49 (n=17) * stable = the mean of a l l samples from the north, south, and unmixed Lambert Channel, during each sampling period. 4.23 Nutrient Analy; si s Nutrient samples were obtained from various locations and depths throughout the region i n 1985, 1986, and 1987 as well as from the 10 1 l i t e r samples c o l l e c t e d for r a d i o a c t i v e 1 4 C uptake studies during June, July, and August of 1987. Upon c o l l e c t i o n of the 10 1 samples, 50 ml aliquots were removed from each container and gently f i l t e r e d through a Whatman 934-AH glass f i b e r f i l t e r (25 mm diameter) mounted i n a M i l l i p o r e Swinnex apparatus to remove p a r t i c u l a t e matter. The f i l t r a t e was then frozen i n acid-washed 30 ml Nalgene b o t t l e s . Analysis for n i t r a t e (NO3 + NO2) was c a r r i e d out following the procedures out l i n e d i n Wood et a l . 80 (1967). Phosphate (PO^) determination was c a r r i e d out using a Techmcon Auto Analyzer following the procedures outlined by Chan and Ri l e y (1965) and Hager et a l . (1968). Concentrations of n i t r a t e + n i t r i t e , phosphate, as well as s a l i n i t y and temperature of primary production samples upon c o l l e c t i o n (Day 1) are given i n Table 4.3. Lower l i m i t s of detection were 0.10 pig a t . l . - 1 for NO3 + NO2 and 0.05 pig a t . I - 1 - f o r P O 4 . Mean concentrations at c o l l e c t i o n of n i t r a t e + n i t r i t e and phosphate from a l l mixed and stable samples during 1986 and 1987 are given i n Table 4.4. Table 4.3 N i t r a t e + n i t r i t e and phosphate concentrations, s a l i n i t y and temperature of the i n i t i a l water samples at time of c o l l e c t i o n obtained for primary p r o d u c t i v i t y determinations i n June, July, and August 1987. A)June 17, 1987 N03+N02 P0 4 S a l i n i t y Temperature pg a t . l ' -1 ppt Degrees C Mixed A: B: C: 4 .00 1.90 2.90 0.90 0.65 0.85 • 26.9 13.1 Stable mean S.E.(n=4) 0.30 0.10 0.25 0.05 26.2 14 .2 B)July 12, 1987 Mixed A: B: 1.90 2.00 26.3 15.6 Stable mean S.E.(n=6) 0.10 0.01 0.35 0.05 24.3 17 .6 CJAugust 8, 1987 Mixed 2.10 0.80 27.2 15.7 Stable mean S.E.(n=6) 0.20 0.10 0.25 0.01 26.0 17.2 81 Table 4.4 Concentrations of n i t r a t e + n i t r i t e and phosphate during 1986 and 1987 from a l l samples obtained at the surface from mixed and stable water masses. DATE N03 + N02 P04 a t . l - 1 Mixed Stable Mixed Stable June 23,1986 1.5 2.00 4.8 7.0 0.5 0.2 1.30 2.85 2.1 2.0 July 9,1986 1.3 0.5 1.70 0.25 June 17,1987 2.9 0.85 4.0 1.9 0.5 0.2 0.1 0.2 0.90 0.65 0.25 0.25 0.30 0. 15 Julv 12,1987 2.0 1.9 0.1 0.1 0.1 0.1 0.1 0.2 0.4 0.3 0.4 0.35 0.30 0.35 Auqust 8,1987 2.1 1.7 0.2 0.1 0.1 0.1 0.1 0.1 0.80 0.55 0.25 0.25 0.30 0.25 0.30 0.25 Mean= 2.8 0.2 1.00 0.55 S.E.= 0.6 0.1 0.26 0. 13 n= 11 19 9 19 82 4.24 Zooplankton Sampling Zooplankton samples were obtained at a depth of 1 m i n the various water masses through u t i l i z a t i o n of the deck-mounted pump (previously described). Volumes of samples obtained were determined by ascertaining the time required to f i l l a container of known volume. Representative zooplankton samples were f i l t e r e d from the water exhaust of the pump using a 54 pm Nitex mesh plankton net held i n the exhaust f o r a measured period of time. Zooplankton samples were preserved i n a 4% borax buffered formalin solution (Parsons et a l . 1984). Samples i n the laboratory were washed through a 202 pm sieve (thus e l i m i n a t i n g extrusion through the net due to pressure) and those retained were counted to species, (Fulton 1968; Gardner and Szabo 1982) when sample sizes were not p r o h i b i t i v e . Species determination was performed u t i l i z i n g a Wild d i s s e c t i n g microscope and Bogorov t r a y . Subsampling was performed u t i l i z i n g the Folsom s p l i t t e r technique (McEwen et a l . 1954; Wilborg 1962; Horwood and Driver 1976) when copepod d e n s i t i e s were too high and the f i r s t 100 copepods were i d e n t i f i e d to species, with values extended to incorporate the entir e sample. Zooplankton d e n s i t i e s were compared between the two water types using a Student's t -t e s t (Sokal and Rohlf 1981). When the mean was p o s i t i v e l y c o r r e l a t e d with the variance a logarithmic transformation was performed to make the variance, independent of the mean (Sokal and Rohlf 1981). 83 Figure 4.4 Copepod densities.-! - obtained by pumping i n the mixing generation s i t e and the adjacent stable water columns during June, July, and August, 1987. Samples were obtained from a depth of 1 m and f i l t e r e d through a 54 pm mesh net. (Error bars represent 1 Standard Error, N=6). D Z3 C O EE cn "c o 4000 3000 2000--1000-0 Copepod Densi t ies C Z J = P l u m e • • = S t a b l e June July Augus t — 3 Figure 4.5 Copepod n a u p l i i densities.m obtained by-pumping i n the mixing generation s i t e and the adjacent stable water columns during June, July, and August, 1987. Samples were obtained from a depth of 1 m and f i l t e r e d through a 54 m^ mesh net.(Error bars represent 1 Standard Error, N=3). 2 5 0 0 2 0 0 0 1 5 0 0 1 0 0 0 5 0 0 -0 -Copepod Nauplii Densities LZD=Plume • • = S t a b l e June July August Figure 4.6 Total zooplankton densities.m obtained by pumping i n the mixing generation s i t e and the adjacent stable water columns during June, July, and August, 1987. Samples were obtained from a depth of 1 m and f i l t e r e d through a 54 pm mesh net.(Error bars represent 1 Standard Error , N=3). 7000 6000-5000- -4000- -3000 2000- -1000- -0 Total Zooplankton Densities EZ~J=Plume • • =Stab!e June Ju ly A u g u s t 86 Zooplankton species composition and d e n s i t i e s were examined on June 16, July 16, and August 8, 1987 (during daylight hours) v i a pumping i n the region of the mixing generation s i t e . Individual samples were obtained i n separate mixing events (increasing v a r i a b i l i t y ) . The d e n s i t i e s and species composition were compared between the mixing region and stable water column. Densities of — 3 • ~~ organisms.m were grouped in t o copepods (adults and copepodites, F i g . 4.4), n a u p l i i (copepod naupliar stages, F i g . 4.5), as well as t o t a l zooplankters (Figure 4.6). Table 4.5 gives d e n s i t i e s as well as s t a t i s t i c a l s i g n i f i c a n c e (p < 0.05) of the various groups l i s t e d above, over the 3 sampling periods. Copepod species obtained were representative of nearshore zooplankton communities with the dominant copepod genera being A c a r t i a and Pseudocalanus i n a l l samples. 4.3 Discussion 4.31 Nutrient Additions Additions of n i t r a t e + n i t r i t e due to mixing caused a s i g n i f i c a n t increase (2.6 a t . l - 1 ) i n n i t r a t e and n i t r i t e as compared to the s t r a t i f i e d water column. These additions of new n i t r a t e + n i t r i t e , when extrapolated to the net volume of mixed water i n June and July, 1986 (Chapter 3) lead to an increase of n i t r a t e + n i t r i t e between 185 to 3 o 4.2x10 J kg with a mean increase of 1.3x10 kg of new n i t r a t e being i n j e c t e d i n t o the euphotic zone. 87 Table 4.5 Zooplankton densities.m (greater than 202 pm) i n mixed vs stable samples as obtained by pumping and si z e separation i n the laboratory. (Std denotes standard deviation) ZOOPLANKTON JUNE JULY AUGUST (n=6) (n=3) (n=3) Copepods Mixed * 1022 2437 2864 Std 925.3 158.8 1797 Stable 273 953 1363 Std 108 262.9 489.0 P r o b a b i l i t y p <.05 p <.05 p >.05 Nau p l i i Mixed * 1174 1551 732 Std 1476 36.2 429 Stable 125 1568 1889 Std 114 320.3 468 P r o b a b i l i t y p <.05 p >.05 p >.05 Total Mixed * 3036 4495 4491 Std 3402 188.2 2629 Stable 611.0 3014 5236 Std 288 527 1779 P r o b a b i l i t y p <.05 p <.05 p >. 05 * denotes logarithmic transform of data. The stoichiometric elemental composition of the major elements (by atoms) i n the plankton most commonly quoted i s 106 C:263 H:110 0:16 N:l P: 0.7 S ( Trudinger et a l . , 1979; Stumm and Morgan, 1981). Rapidly growing phytoplankton e x h i b i t uptake r a t i o s i n congruence with the Re d f i e l d r a t i o (Redfield, 1958) of 106 C:16 N:l P which i s a stoichiometric r a t i o often observed i n ocean plankton (Redfield et a l . , 1963). The Redfield r a t i o by weight i s 42 C:7 N: 1 P (Harris, 1986) with some v a r i a b i l i t y being reported by Boyd 88 and Lawrence (1967) who recorded a number of freshwater s i t u a t i o n s where r a t i o s of various elements by weight were 116 C: 9.9 N: 1 P. Harris (1986) states that a more representative phytoplankton r a t i o i s 166 C: 20 N: I P (by atoms). Harris (1986) averaged a l l marine and freshwater data to produce regression equations f o r c o r r e l a t i o n s between p a r t i c u l a t e C, N, and P. The l e a s t squares regressions by weight were: C= 8 8 P 0 * 8 8 2 (r=0.996) (4.1) N=12.1P 0' 8 8 2 (r=0.996) (4.2) with the exponents being s i g n i f i c a n t l y d i f f e r e n t from 1.0 at the p < 0.01 l e v e l . Accordingly the C:P and N:P r a t i o s become a function of P: C:P= 8 8/P 0' 1 1 8 (4.3) N:P= 12.1/P 0' 1 1 8 (4.4) with the r a t i o of C:N constant at 7.3 by weight. U t i l i z i n g the constant weight r a t i o on the mass of nitrogen added i n June and July, 1986, the t h e o r e t i c a l increase i n phytoplankton carbon due to the mixing events, ranges from 2.3x10 to 4.9x10 kg.d of new production with a mean value of 1.6xl0 2 kg.d - 1. 4.32 Primary Production The analysis of primary production over the three sampling periods i l l u s t r a t e s that each mixing event sampled, d i f f e r e d s i g n i f i c a n t l y from primary production at 1 m i n the stable water mass. Individual each mixing events showed an increase i n production over primary production i n the unmixed samples. Each mixing event had a d i f f e r e n t concentration of n i t r a t e + n i t r i t e and probably differences i n phytoplankton c e l l physiology due to the c h a r a c t e r i s t i c s of each mixing event. The production, mean mixed vs mean stable samples i s s i g n i f i c a n t l y d i f f e r e n t (p < 0.05) i n the sampling periods for only the f i r s t 3 days of the incubation samples. The exceptions are day 1 of the August sampling period as well as the July sampling period (due to high v a r i a b i l i t y of the mixed primary production i n July. Thus the increase i n production i n the i n i t i a l 3 days of the 5 day incubations was concluded to be due to the addition of n i t r a t e by the mixing event. Table 4.2 gives primary production over the f i r s t 3 days of the incubation periods. The primary production over a l l 3 sampling periods for a l l — 1 the mixed water mass was determined to be 16.9 mg Cm , s i g n i f i c a n t l y d i f f e r e n t from 3.1 mg C m - 3 (p < 0.05) for the stable water column (Table 4.1). An increase i n net production of 13.8 mg Cm when applied to the amount of mixing occurring during periods during June and July 1986 (Chapter 3) of 6.6xl0 7 to 1.6xl0 9 m3 with a mean of 4.5xl0 8 m could lead to a net increase i n primary production of 9 9 — 1 0.2x10 to 3.2x10 kg.d of new production over the ambient 2 production i n the region with a mean increase of 1.0 xlO k g . d - 1 of new production. 9 0 4.33 Zooplankton D i s t r i b u t i o n s Zooplankton d e n s i t i e s per m i n the mixed water mass were s i g n i f i c a n t l y (p < 0.05) d i f f e r e n t for copepods and t o t a l zooplankton during the June and July sampling periods. The mixing event would conceivably break down the c h l o r o p h y l l maximum and the c l o s e l y associated zooplankton maximum (Herman et a l . , 1981), r e s u l t i n g i n the mixing of phytoplankton and zooplankton into the water column and elevating d e n s i t i e s of phytoplankton and zooplankton i n the mixed water mass. Calanoid naupliar stages however did not present a c l e a r d i s t r i b u t i o n trend with the mixed water mass having greater d e n s i t i e s i n the June sampling period, and no s i g n i f i c a n t d i f f e r e n c e i n the July and August sampling periods. Deep water surface migrating species of copepods were not obtained i n the mixed samples or stable samples demonstrating that the depth of mixing was shallow as i s evident i n Figures 3.31-3.33. Absence of deep water species i s to be a n t i c i p a t e d due to the depth of the channel, energetics of the event and v e r t i c a l migration depth requirements of these species. Deep water upwelling would have been ind i c a t e d by reduced densities of surface non-migrating species due to the d i l u t i o n by deep water as well as evidence of deep water species i n the mixing event. August zooplankton sampling did not show s i g n i f i c a n t d i f f e r e n c e s between the stable and mixed water samples poss i b l y due to a wind mixing event p r i o r to sampling. 91 4.4 Conclusions I n j e c t i o n of nutrient r i c h deep water due to t i d a l mixing has been shown to r e s u l t i n an increase i n primary production i n the euphotic zone. Increases found i n t h i s study are - 65 % of the t h e o r e t i c a l increases i n primary production expected due to Redfield stoichiometry. The primary production determined i n t h i s study may be less than the t h e o r e t i c a l amount determined by Redf i e l d stoichiometry due to the p h y s i o l o g i c a l condition and species composition of the phytoplankton i n the nutrient enriched mixed water as well as er r o r of estimation due to the inherent problems with 1 4 C techniques (Harris 1986). The mixing event, occurring o f f Shingle Spi t has been demonstrated to s i g n i f i c a n t l y a l t e r the f i n e scale patchiness of nutrients, and primary production. The increase i n production observed here on the scale of meters to hundreds of meters should a f f e c t the i n d i v i d u a l i n t e r a c t i o n s of zooplankton with food sources (Haury et a l . 1978). The de s t i n a t i o n of these f i n e - s c a l e patches of food may influence the coarse-scale d i s t r i b u t i o n of zooplankton i n the region, leading to an increase i n production at higher tro p h i c l e v e l s . 92 CHAPTER 5  BIOLOGICAL OCEANOGRAPHY  Regional e f f e c t s 5.1 I n t r o d u c t i o n The v e r t i c a l t r a n s f e r of energy and m a t e r i a l s d r i v e n by s t a b i l i z a t i o n and d e s t a b i l i z a t i o n of the water column, i s one o f the b a s i c mechanisms of p r o d u c t i v e marine ecosystems (Legendre, 1981). The s c a l e of d e s t a b i l i z a t i o n i n the marine environment i s determined by the type and i n t e n s i t y of the p e r t u r b a t i o n r e l a t i v e t o the s t a b i l i t y of the water column. The s c a l e , be i t temporal or s p a t i a l i s a d e t e r m i n i n g f a c t o r on the patchy d i s t r i b u t i o n of organisms observed i n the marine environment. Other v a r i a t i o n s may be due t o v a r i a t i o n s i n p r o d u c t i o n , and b e h a v i o r or a combination of th e s e mechanisms (Stavn, 1971; Longhurst, 1981). Understanding marine hydrodynamics, as a c o n s t r a i n t on the dynamics of ecosystems, r e q u i r e s an assessment of i t s impact on primary producers and the subsequent t r a n s f e r up the f o o d web. T h i s c h a p t e r w i l l examine the c o a r s e - s c a l e v a r i a t i o n i n zooplankton d e n s i t i e s around Hornby I s l a n d w i t h r e s p e c t t o net t r a n s p o r t of n u t r i e n t s and i n c r e a s e d primary p r o d u c t i o n a l r e a d y determined on the f i n e s c a l e i n Lambert Channel. The d e t e r m i n a t i o n of the net t r a n s p o r t of i n c r e a s e d p r i m a r y p r o d u c t i o n and an e s t i m a t i o n of the d e s t i n a t i o n w i l l 9 3 e n a b l e t h e d e t e r m i n a t i o n o f u t i l i z a t i o n b y s e c o n d a r y c o n s u m e r s . U t i l i z a t i o n o f t h e i n c r e a s e d z o o p l a n k t o n s t a n d i n g s t o c k s w i l l be d e t e r m i n e d t h r o u g h t h e e x a m i n a t i o n o f t h e g u t c o n t e n t s o f a p r e d a t o r ( a d u l t O n c o r h y n c h u s k i s u t c h ) i n t h e r e g i o n . P r e s e n c e o f t h e z o o p l a n k t o n f r o m c o a r s e - s c a l e a g g r e g a t i o n s i n t h e g u t s o f t h e s e p r e d a t o r s w i l l i n d i c a t e u t i l i z a t i o n o f t h e s e o r g a n i s m s a s a f o o d s o u r c e . 5.2 M e t h o d s 5.21 Z o o p l a n k t o n S a m p l i n g Z o o p l a n k t o n s a m p l e s w e r e c o l l e c t e d f r o m 32 s t a t i o n s i n J u l y a n d S e p t e m b e r o f 1986 i n a g r i d - l i k e p a t t e r n e n c o m p a s s i n g b o t h t h e s o u t h (20 S t n s ) a n d n o r t h e n d (12 S t n s ) o f H o r n b y I s l a n d ( F i g u r e s 5.1 a n d 5 . 2 ) . I n 1987 t w e n t y s i x s t a t i o n s w e r e s a m p l e d i n J u n e , J u l y , a n d A u g u s t w i t h 14 S t a t i o n s e x a m i n e d i n t h e s o u t h a n d 12 i n t h e n o r t h ( F i g u r e s 5.3 a n d 5 . 4 ) . V e r t i c a l n e t h a u l s u t i l i z i n g a SCOR n e t w i t h 405 ]jm mesh a n d an o p e n i n g d i a m e t e r o f 72 cm, w e r e p e r f o r m e d d u r i n g t h e h o u r s o f 2300 t o 0500 t o a d e p t h o f 65 m w i t h t h e h a u l s p e e d b e i n g 1 m . s - 1 . S a m p l i n g o c c u r r e d o n l y when t h e d e e p s c a t t e r i n g l a y e r was a b o v e 65 m. D e p t h o f t h e d e e p s c a t t e r i n g l a y e r ( H e r s e y a n d B a c k u s , 1 9 6 2 ; R i c h t e r , 1985) was a s c e r t a i n e d t h r o u g h u t i l i z a t i o n o f a n e c h o - s o u n d e r ( H u m m i n g b i r d ). 94 Figure 5.1 Location of the 20 southern Stations u t i l i z e d f o r v e r t i c a l zooplankton sampling during the 1986 season. Depth contours are i n meters. 95 F i g u r e 5.2 L o c a t i o n of the 12 northern S t a t i o n s u t i l i z e d f o r v e r t i c a l zooplankton sampling d u r i n g the 1986 season. Depth contours are i n meters. Figure 5.3 Location of the 14 southern Stations u t i l i z e d for v e r t i c a l zooplankton sampling during the 1987 season. Depth contours are i n meters. SCALE 1: 80.000 97 F i g u r e 5.4 L o c a t i o n o f t h e 12 n o r t h e r n S t a t i o n s u t i l i z e d f o r v e r t i c a l z o o p l a n k t o n s a m p l i n g d u r i n g t h e 1987 s e a s o n . Depth c o n t o u r s a r e i n m e t e r s . 98 Zooplankton samples were preserved i n a 4% borax buffered formalin solution upon capture (Parsons et a l . , 1984). Samples i n the laboratory were f i l t e r e d through a 471 /jm sieve and those organisms retained were counted by group (Amphipoda, Chaetognatha, Euphausiia, Ctenophora, Polychaeta, and Copepoda) u t i l i z i n g a Wild d i s s e c t i n g microscope and a Bogorov tray. Species i d e n t i f i c a t i o n and q u a n t i f i c a t i o n was performed on copepods following Fulton (1968) and Gardiner and Szabo (1982). Due to the large number of copepods per sample species i d e n t i f i c a t i o n was c a r r i e d out on the f i r s t 100 copepods, with these values extended to incorporate the en t i r e sample. When analysis of the sample due to siz e was p r o h i b i t i v e , the samples were subsampled u t i l i z i n g the Folsom s p l i t t e r technique (McEwen et a l . , 1954; Wilborg, 1962; Horwood and Driver, 1976). Due to time constraints, and the large areas to be surveyed, r e p l i c a t i o n of samples to determine v a r i a b i l i t y was performed randomly throughout the sampling region during the various sampling periods (weather conditions during some sampling periods also made i t impossible to sample a l l s t a t i o n s ) . Therefore r e p l i c a t i o n was done on random sta t i o n s , with three samples obtained at each s t a t i o n chosen fo r s t a t i s t i c a l a n a l y s i s . In order to determine the v a r i a b i l i t y of the aforementioned groups, the standard error of the mean was converted to a percent of the mean at each r e p l i c a t e d s t a t i o n . These values were pooled and the mean percent standard error determined (Sokal and Rohlf, 1981). 99 In order to compare the densities of the populations of the north and south sampling areas, as well as to determine i f population means changed between sampling periods, means of the populations were compared using a Student's t - t e s t at a l e v e l of s i g n i f i c a n c e of 0.05 (Sokal and Rohlf, 1981). Since one of the assumptions of the t - t e s t i s that the means of the north and south sampling areas have equal variances a preliminary F-test was performed. If the F-test proved severe deviations from the equality of variance assumption, a log transformation was performed on the data and the F-t e s t again performed. If the equality of variance assumption was s t i l l v i o l a t e d the Mann-Whitney U te s t (nonparametric test) was used instead of the t - t e s t . In order to determine i f a s i n g l e s t a t i o n sample d i f f e r s from the mean density of the r e s t of the region a Student's t - d i s t r i b u t i o n was employed to t e s t s i g n i f i c a n c e (Sokal and Rohlf, 1981). As south stations 1, 2, and 3 were deemed to be the most l i k e l y to be influenced by increased production, these stations were compared to the rest of the southern s t a t i o n s . 5.22 Zooplankton Resource U t i l i z a t i o n Samples of gut contents from adult coho salmon (Oncorhynchus kisutch) were obtained from those caught by sport fishermen during July and August of 1987. Samples represent f i s h obtained by angling near Phipps Point on the North end of Hornby Island and Norman Point on the south end of Hornby Island (Figure 5.3). Specimens were gutted, the 100 stomachs removed and fixed i n 10% formalin as soon as possible following c o l l e c t i o n to minimize enzymatic breakdown of the gut contents (Eggers, 1977). Gut contents were removed i n the laboratory and organisms were counted by group (Amphipoda, Chaetognatha, Euphausiia, Ctenophora, Polychaeta, Decapoda, and Copepoda) u t i l i z i n g a Wild d i s s e c t i n g microscope and a Bogorov t r a y . Determination of prey s e l e c t i v i t y by adult coho salmonids was performed u t i l i z i n g Berg's (1979) modification of Ivlev's (1961) index of prey e l e c t i v i t y , where e l e c t i v i t y f o r species i i s given by the equation: E i= loglO (%Ni i n the ingested food^ (5.2) (%Ni i n the p o t e n t i a l l y a v a i l a b l e food) where ingested food i s the contents of the gut samples obtained from the aforementioned adult coho salmon. The p o t e n t i a l l y a v a i l a b l e zooplankton i s assumed to be represented by populations near sight of capture. Phipps point at the north i s represented by Stations North 1, 2, 3, 8, and 9, while Norman Point i s represented by zooplankton samples obtained from South Stations 1, 2, 6, 7, and 8. P o t e n t i a l zooplankton populations a v a i l a b l e for consumption i n each area are taken as the mean concentrations of organisms a v a i l a b l e i n each area during July and August of 1987. 101 5.3 Results 5.31 Net Flow Figures 3.3 to 3.18 give the current speed and d i r e c t i o n of various Aanderaa stations on a 20 min c y c l e . Table 5.1 gives the net flow v e l o c i t i e s during the sampling period from a l l Aanderaa stat i o n s . Cycles, where the f u l l data set f o r the 28 day "period (maximum spring t i d e to maximum spring tide) are not a v a i l a b l e due to meter replacement or f a i l u r e , are not included. Table 5.1 Net flow v e l o c i t y and d i r e c t i o n i n Lambert Channel as determined from Aanderaa meters. Period Direction V e l o c i t y (cm.s ) Depth (m) Station 03/30-04/27 ebb 1.8 23 1 03/30-04/27 ebb 1.6 29 2 03/30-04/27 ebb 1.4 42 2 05-25-06/22 ebb 4.9 29 2 05-25-06/22 ebb 1.6 42 2 06/22-07/20 ebb 6.4 29 2 06/22-07/20 ebb 1.9 42 2 07/20-08/20 ebb 0.8 42 2 05/25-06/22 ebb 1.8 29 3 05/25-06/22 ebb 2.4 42 3 06/22-07/20 ebb 2.2 29 3 06/22-07/20 ebb 4.0 42 3 5.32 Zooplankton D i s t r i b u t i o n Figures 5.5 to 5.10 show the zooplankton d e n s i t i e s obtained during 1986 and 1987 at the stations around Hornby Island. Tables 5.2-3 give the t-values or Mann-Whitney values comparing de n s i t i e s of the northern stations to the 102 T a b l e 5.2 Mann-Whitney s t a t i s t i c s comparing the 1987 n o r t h vs south d i s t r i b u t i o n s of Amphipoda, E u p h a u s i i a , and Copepoda. COMPARISON MEAN SD ^ - c r i t t t e s t a c c e p t or or o r u c r i t U t e s t r e j e c t Amphipoda, 1987 June S 2 . 0 x l 0 3 9 .2x10^ N 4 . l x l O 2 2 . 8 x l 0 2 80 99.5 r e j e c t * J u l y S 2 .3x10;? 1 . 2 x l 0 3 N 4 . 2 x l 0 2 2 . l x l O 2 95 119 r e j e c t * August S 3 . 5 x l 0 3 1 . 9 x l 0 3 N 6 . 2 x l 0 2 6 . 2 x l 0 2 95 122 r e j e c t * E u p h a u s i i a , 1987_ June S 1 . 5 x l 0 3 7 .8x10* N 3 . 3 x l 0 2 1 . 9 x l 0 2 86 111 r e j e c t * J u l y S 3 . 5 x l 0 3 2 . 6 x l 0 3 N 1 . l x l O 2 1 . l x l O 3 95 104 r e j e c t * August S 8 . 3 x l 0 3 5 . l x l O 3 N 2 . 1 x l 0 3 1 .2xlO J 95 120 r e j e c t * Copepoda, 1987 A June S 2 . 1 3 x l 0 4 4 .44x10^ N 5 . 7 0 x l 0 3 6 . 8 5 x l 0 3 86 108 r e j e c t * J u l y S 3 . 1 6 x l 0 4 2 . 4 5 x l 0 4 N 4 . 2 4 x l 0 3 2 . 9 5 x l 0 3 95 116 r e j e c t * August S 3 . 1 5 x l 0 4 2 .25x10* N 8. 7 6 x l 0 3 7 . 5 5 x l 0 3 95 115 r e j e c t * Ho: eq u a l s ^ 2 and Ha: JJ^ does not equal SD = s t a n d a r d d e v i a t i o n 103 Table 5.3 T-Test and Mann-Whitney s t a t i s t i c s comparing the 1986 north vs south d i s t r i b u t i o n s of Amphipoda, Euphausiia, and Copepoda. COMPARISON MEAN SD ^ c r i t or u c r i t t t e s t or u t e s t accept or r e j e c t Amphipoda, 1986 July S 6.1x10;? 5 .9xl0 3 N 1.2x10:* 7 .7x10;? 145 193 r e j e c t * August S 3.2x10;? 2 • l x l O 3 N 1.6x103 7 .3x10^ 106 112 r e j e c t * Euphausiia, 1986 July S 2.1xl0 3 2 .0x10^ N 3.1x10^ 3 •5xl02 126 152.5 r e j e c t * Sept. S 2.3xl0 3 1 .8xl0 3 N 1.8xl0 3 2 .6xl0 3 2.064 .01 accept Copepoda, 1986 A July S 4.52xl0 4 4 .64x10; N 1.46x10; 1 .18x10; 145 169 r e j e c t * Sept. S 4.48x10; 3 .57xl0 4 N 1.98xl0 4 5 .57xl0 3 106 116 r e j e c t * Two-sample t - t e s t for the two-tailed hypotheses, Ho: p-\ equals and Ha: p^ does not equal * s i g n i f i e s Mann-Whitney U t e s t SD = standard deviation 104 Table 5.4 T-Test and Mann-Whitney s t a t i s t i c s comparing the d e n s i t i e s of Amphipoda, Euphausiia, and Copepoda between the June, July, and August 1987 sampling periods. Both the north and south regions are examined. COMPARISON MEAN SD t c r i t t t e s t accept or or or u c r i t u t e s t r e j e c t South Amphipoda,1987 June 2.0xl0 3 9 .2x10;? 132 104 June vs July July 2.3xl0 3 1 .2xl0 3 accept* August 3.5xl0 3 1 .9xl0 3 2.06 1.97 July vs August accept „ South Euphausiia-1987 June 1.5x10;: 7 .8x10^ 141 143 June vs July July 3.5xl0 3 2 .6xl0 3 r e j e c t * August 8.3xl0 3 5 . l x l O 3 141 162 July vs August r e j e c t * South Copepoda, 1987 A June 2.13x10'* 1 .23xl0 4 141 120 June vs July July 3.16x10J 8 •83xl0 4 accept* August 3.16xl0 4 2 .25xl0 4 2.06 1.37x10 JulyvsAugust accept North Amphipoda,.1987 June 4.1x10^ 2 .1x102 2.231 0.036 June vs July July 4.2x10^ 1 .9x10^ accept August 6.2x10 5 .2xl0 2 64 54 July vs August accept* North Euphausiia. 1987 June 3.3x10^ 1 .9x10^ 57 57 June vs July July l . l x l O 3 3 .5x10;? r e j e c t * August 2.1xl0 3 1 .2xl0 J 2.12 1.076 July vs August r e j e c t North Copepoda, 19 87 June 5.70xl0 3 2 .59xl0 3 2.11 1.076 June vs July July 4.24xl0 3 2 •95xl0 3 accept August 8.76xl0 3 7 .54xl0 3 64 55 July vs August accept* Two-sample t - t e s t for the two-tailed hypotheses, Ho: p:-\ equals p 2 a n c * Ha: does not equal / J 2 * s i g n i f i e s Mann-Whitney U test SD = standard deviation 105 Table 5.5 T-Test and Mann-Whitney s t a t i s t i c s comparing the d e n s i t i e s of Amphipoda, Euphausiia, and Copepoda between the June, July, and August 1986 sampling periods. Both the north and south regions are examined. COMPARISON MEAN SD t c r i t or t t e s t or accept or U c r i t U t e s t r e j e c t South Amphipoda. 1986 J u l y 6.7xl0 3 5. 9xl0 3 273 303 r e j e c t * September 3.2xl0 3 2. South Euphausiia. 1986 l x l O 3 July 2.1xl0 3 2. September 2.3xl0 3 1. South Copepoda, 1986 OxlO 3 8 x l 0 3 2.024 0.001 accept July 4.52xl0 4 4. 64xl0 4 2.024 0.08 accept September 4.48xl0 4 3. 57xl0 4 North Amphipoda. 1986 July 1.2xl0 3 7. September 1.6xl0 3 7. North Euphausiia. 1986 7xl0 2 3x10^ 2.131 1.97 accept J u l y 3.1x10^ 3. September 1.8xl0 3 2. North Copepoda, 1986 4 x l 0 2 6xl0 3 56 43.5 accept* J u l y 1.47x10* 1. September 1.98xl0 4 5. 18xl0 4 57xl0 3 273 61 accept* Two-sample t - t e s t for the two-tailed hypotheses, Ho: u± equals pi 2 a n c * Ha: pi-y does not equal pi2 * s i g n i f x e s Mann-Whxtney U t e s t SD = standard deviation d e n s i t i e s of the southern stations f o r the groups Amphipoda, Euphausiia, and Copepoda for 1986 and 1987. Tables 5.4-5 compare the d e n s i t i e s i n the northern and southern regions between sampling periods during 1986 and 1987. Tables 1-54 xn Appendxx 1 gxve the actual densxties per m at the various stations during 1986 and 1987, as well as the dominant species of Copepoda at each s t a t i o n . Appendix 2 d i s p l a y s the d e n s i t i e s at each s t a t i o n of Amphipoda, Euphausiia, and Copepoda on h o r i z o n t a l maps of the northern and southern stations during 1986 and 1987. 106 5.33 Amphipoda D i s t r i b u t i o n D i s t r i b u t i o n of the members composing the Amphipoda group during 1986 and 1987 was extremely v a r i a b l e with a mean percentage standard error of 10.2 determined per sample (S.E.=1.6, n=22). South s t a t i o n 1 had a maximum density of 2.93xl0 4 organisms.m~ 2 i n July, 1986 which was s i g n i f i c a n t l y d i f f e r e n t from the rest of the region ( c r i t i c a l t value of tgtj=2.09, n=19) with a t value of 7.85. The mean density i n the rest of the southern region at the time was 6.8x10 organisms.m with a standard e r r o r of 6.8xl0 2. In August, 1987 a density of 7.29xl0 3 organisms.m - 2 ( c r i t i c a l t value of t gc.=2.16, n=13) with a t value of 7.9 was obtained. The mean i n the southern region at that time was 3.2x10 organisms.m with a standard error of 4.6x10 . Examination of the horizontal plots i n Appendix 2 showed some pattern i n August, 1987 and July, 1986. In August 1987 (Appendix 2, Figure 3) the maximum density i n the region was 7.29x10 organisms.m at south s t a t i o n 1. Densities downstream of Lambert Channel were seen to be higher than the r e s t of the region possibly demonstrating a transport from south s t a t i o n 1 to south stations 6, 9, 10, and 12. The same trend was seen i n the July sampling period of 1986 (Figure 5.5) while the northern region showed no such trend (Figure 5.6). The highest density 2.93xl0 4 organisms.m was again found at south s t a t i o n 1, with stations downstream (south stations 6, 9, 10, and 12) again suggesting a transport away from south s t a t i o n 1. Figure 5.5 Horizontal d i s t r i b u t i o n of the group amphipoda at the southern stations during July, 1986. Densities i n numbers per m . F i g u r e 5.6 H o r i z o n t a l d i s t r i b u t i o n of the group amphipoda the n o r t h e r n s t a t i o n s d u r i n g J u l y , 1986. D e n s i t i e s i n numbers per m . 109 F i g u r e 5.7 Amphipoda d e n s i t i e s , d u r i n g the 1986 sampling p e r i o d s a t s t a t i o n s A) North of Lambert Channel and Hornby I s l a n d and B) South of Lambert Channel and Hornby I s l a n d as determined by v e r t i c a l net hauls u t i l i z i n g a 4 05 pm mesh SCOR n e t . AMPHIPODA DENSITIES 1986 NORTH STATIONS CN o o o x to _ l < Q > 3 -2-1 --L7_Z)=July • • = S e p t e m b e r -Ql I 3 4 5 6 7 8 J STATION NUMBER AMPHIPODA DENSITIES 1986 SOUTH STATIONS 11 12 CN E ' o o o CO I < o > Q 2 30-2 5 -20--15 10-5 -0 1 C Z ] = J u l y • • =September \m 1 2 3 4 5 6 7 8 9 10111213141516171819 20 STATION NUMBER 110 Figure 5.8 Amphipoda den s i t i e s , during the 1987 sampling periods at stat i o n s A) North of Lambert Channel and Hornby Island and B) South of Lambert Channel and Hornby Island as determined by v e r t i c a l net hauls u t i l i z i n g a 405 pm mesh SCOR net. AMPHIPODA DENSITIES 1987 NORTH STATIONS < Q > 2000 T-1750-: 1500-1250--1000-: 750-; 500 •-250 :; 0-- nl v n ibtl \ZD =June • • =July m =August 8 9 STATION NUMBER AMPHIPODA DENSITIES 1987 SOUTH STATIONS C N if) _ l < > 8000-r 7000 --6000 --5000 --4000 - • 3000--2000--1000--0--i i=June — =July I \ I =August 1 2 3 4 5 6 7 8 9 10 1 1 12 13 14 15 STATION NUMBER I l l Comparisons of densities i n the southern sampling region and the northern region (Table 5.2-3) show that these populations d i f f e r s i g n i f i c a n t l y from each other. Mean density i n the southern sampling region i s always higher than the mean density of the northern sampling region. Comparisons between sampling periods show a s i g n i f i c a n t d i f f e r e n c e i n the mean density of organisms i n only the July to September, 1986 sampling period. A decrease i n density of 3 • 9 3.5x10 organisms.m i s observed at t h i s time (Table 5.4-o — 9 5). An increase of 1.5x10 organisms.m i s observed between June, and August of 1987 although no s i g n i f i c a n t d i f f e r e n c e i s observed between June and July and July and August. Closer examination of the data shows that at south s t a t i o n 1, the d e n s i t i e s i n 1987 increase from 2.5x10 i n June to 3 - 9 ^ 7.3xlO J organisms .m-'' i n August (up 4.8x10 J) compared to the mean increase of the region of 1.5xl0 3 organisms.m - 2 for the southern sampling region. In 1986 rather than an increase at s t a t i o n 1 a decrease i s evidenced, with a decrease i n the mean density also observed for the r e s t of the region. 5.34 Euphausiia D i s t r i b u t i o n Species composing the Euphausiia group were the most v a r i a b l e i n density with a mean percentage (single) standard error of 14.6 determined per sample (S.E.=2.6, n=20). Again south s t a t i o n 1 had the highest density recorded i n the southern sampling region, at 2.24xl0 4 organisms.m~ 2 i n August 1987 ( c r i t i c a l t value of t QC,=2.16, n=13) with a t 112 value of 4.7. The mean density i n the r e s t of the southern sampling region was 7.2x10J organisms.m z and a standard error of 9.0xl0 2. Examination of the densities i n the north and south sampling regions (Appendix 2) for patterns i n d i s t r i b u t i o n s , showed higher d e n s i t i e s south of Lambert Channel and Hornby Island. In August, 1987 (Figure 5.9) s t a t i o n s o u t h ! had a density of 2.24xl0 4 organisms.m~ 2 with higher d e n s i t i e s observed as well at south stations 2, 5, and 6 and south s t a t i o n 10, suggesting a transport downstream from the high density at south s t a t i o n 1. The northernn region during August, 1987 d i d not show a s i m i l a r pattern (Figure 5.10) with no d e n s i t i e s observed above 4000 organisms m . Examination of the mean population d e n s i t i e s (Tables 5.2-3) show that the densities of the populations i n the north and south d i f f e r s i g n i f i c a n t l y i n a l l the 1987 sampling periods, but only i n the July sampling period i n 1986. In a l l of these sampling times the mean i s higher i n the southern sampling region. In September of 1986, the two regions do not d i f f e r s i g n i f i c a n t l y , p o s s i b l y due to the high v a r i a b i l i t y evidenced i n the northern sampling region. Examination of the change i n d e n s i t i e s between sampling periods (Tables 5.4-5) for euphausiids during 1987 shows a s i g n i f i c a n t d i f f e r e n c e i n den s i t i e s from the June to July and the Ju l y to August sampling periods, and no s i g n i f i c a n t change i n 1986. A mean increase from June to July was 3 9 observed of 2.0x10 organisms.m~, while a mean increase of 113 Figure 5.9 Horizontal d i s t r i b u t i o n of the group euphausiia at the southern stations during August, 1987. Densities i n numbers per m . Euphausi ia August , 1987 £ > 4 0 0 0 4000-1000 # • 1000-100 100 < . I*30' W Figure 5.10 Horizontal d i s t r i b u t i o n of the group amphipoda at the northern stations during August, 1987. Densities i n numbers per m"^. 115 Figure 5.11 Euphausiia d e n s i t i e s , during the 1986 sampling periods at stations A) North of Lambert Channel and Hornby Island and B) South of Lambert Channel and Hornby Island as determined by v e r t i c a l net hauls u t i l i z i n g a 405 pm mesh SCOR net. EUPHAUSIIA DENSITIES 1986 NORTH STATIONS CN JE o o o X CO i < Q > Q 2 9 8 7--6-5 4-3--2 1 -£ 0 CZ3=July • • =September -r JL XL 3 4 5 6 7 8 STATION NUMBER 11 12 EUPHAUSIIA DENSITIES 1986 SOUTH STATIONS CN E N — ' o o o CO I < Q > L_ZI=July • i =September I* ii 1 2 3 4 5 6 7 8 9 1011121314151617181920 STATION NUMBER Figure 5.12 Euphausiia d e n s i t i e s , during the 1987 sampling periods at stations A) North of Lambert Channel and Hornby Island and B) South of Lambert Channel and Hornby Island as determined by v e r t i c a l net hauls u t i l i z i n g a 405 um mesh SCOR net. EUPHAUSIIA DENSITIES 1987 NORTH STATIONS CM O o o CO < g > 4--3-2-1 --I I=June • • = July EX] =August : STATION NUMBER EUPHAUSIIA DENSITIES 1987 SOUTH STATIONS CM o o o x CO I < o > o 2 1 2 3 4 5 6 7 8 9 10 1 1 1 2 1 3 1 4 1 5 STATION NUMBER 4.8x10 organisms.m z was determined from the J u l y to August sampling period. Examination of the d e n s i t i e s at south 1 s t a t i o n shows an o v e r a l l increase of 2.0x10 organisms.m as compared to the 6.8x10 increase observed over the re s t of the southern sampling region. 5.35 Copepoda D i s t r i b u t i o n Species composing the group Copepoda were by f a r the most dominant group taken i n t h i s study. Mean percentage (single) standard error was determined to be 7.55 per sample (S.E.=1.25, n=22). As with the other groups s t a t i o n s c l o s e s t to the southern end of Hornby Island and Lambert Channel had the highest d e n s i t i e s of a l l stations sampled. During July, 1986 a density of 2.31xl0 3 i n d i v i d u a l s per m^  with a t value of 10.09 was obtained ( c r i t i c a l t value of tQ5=2.10, n=18) at s t a t i o n 1. The mean density i n the r e s t of the southern stations was 3.54xl0 4 organisms.m~ 2 with a standard 3 error of 4.33x10 . Densities at s t a t i o n 1 south reached 7.08xl0 4 organism.m~ 2 (t=12.9, t c r i t=2.18, n=12) and 6.95xl0 4 organism.m - 2 (t=9.3, t c r^ t=2.16, n=13) i n J u l y and August of 1987. A density of 8.95xl0 4 i n d i v i d u a l s . m ~ 2 was obtained as well at south st a t i o n 2 i n July of 1987 with a t value of 17.8 ( c r i t i c a l t value of tg5=2.20, n = l l ) . Examination of Appendix 2 for horizontal d i s t r i b u t i o n trends shows that i n June, and July 1987 (Appendix 2, Figures 21, 22) there appears to be a high density region Figure 5.13 Copepoda d e n s i t i e s , during the 1986 sampling periods at stations A) North of Lambert Channel and Hornby Island and B) South of Lambert Channel and Hornby Island as determined by v e r t i c a l net hauls u t i l i z i n g a 405 um mesh SCOR net. COPEPODA DENSITIES 1986 NORTH STATIONS C M o o o x C O I < Q > Q 4 0 j -35--30-: 25--20-15:: 10-5-0--CD=July WM =September 11 12 STATION NUMBER COPEPODA DENSITIES 1986 SOUTH STATIONS 240 j 220:-C M 200 --180--o o 160-o 140-X 120-C O 1 < 100-80--> 60-o z 40-20 -0--EZ3 =July • • =September 1 2 3 4 5 6 7 8 9 10111213141516171819 20 STATION NUMBER 119 Figure 5.14 Copepoda den s i t i e s , during the 1987 sampling periods at stations A) North of Lambert Channel and Hornby Island and B) South of Lambert Channel and Hornby Island as determined by v e r t i c a l net hauls u t i l i z i n g a 405 pm mesh SCOR net. COPEPODA DENSITIES 1987 NORTH STATIONS CN E, o o o X CO I < => o > 24 20 v 16-12 8 ir 4-r 0 CZD =June — =July I \ i =August l u 3 4 5 6 7 STATION NUMBER COPEPODA DENSITIES 1987 SOUTH STATIONS 90 T 8 0 -,—^ CN 7 0 -o o 60--o o 50-X CO 1 40-< o 3 0 -> 20-z 10-0" 1 2 3 4 5 6 7 8 9 1 0 1 1 1 2 1 3 1 4 1 5 STATION NUMBER 120 downstream of Lambert Channel, the highest density found i s not at south s t a t i o n 1, but at south s t a t i o n 5 (June), and south s t a t i o n 2 (July) with d e n s i t i e s higher at st a t i o n s downstream of s t a t i o n 1 than at other s t a t i o n s . The high concentrations observed downstream of s t a t i o n 1 are also observed during the July, 1986 (Appendix 2, Figure 27) sampling period. August 1987 (Appendix 2, Figure 22) shows no sign of d i s p e r s a l from south s t a t i o n 1, but ju s t a high aggregation at t h i s s t a t i o n . Comparison of the mean population d e n s i t i e s between north and south (Tables 5.2-3) show that the two population d e n s i t i e s were s i g n i f i c a n t l y d i f f e r e n t during a l l sampling periods i n 1986 and 1987, with the mean value always greater i n the southern sampling region. Examination of the change i n mean density between sampling periods shows that i n the southern region there was no s i g n i f i c a n t change between the mean d e n s i t i e s . The mean increase i n d e n s i t i e s for the southern region from June to August 1987 was 1.13xl0 4 individuals.m~ 2. Examination of the increase at s t a t i o n south 1 from June to August, 1987 was 3.09xl0 4 i n d i v i d u a l s . m ~ 2 . Several species were dominant i n samples obtained i n both 1986 and 1987 (Appendix 1). Overall Metridia spp. dominated i n most samples but occasionally i n d i v i d u a l stations were dominated by Pseudocalanus or Neocalanus spp. In stations with shallower depths A c a r t i a spp. dominated on occasion over Metridia spp. and Pseudocalanus spp. 121 5.36 Zooplankton Resource U t i l i z a t i o n Major prey groups u t i l i z e d by kisutch during t h i s study are summarized i n Table 5.6. 0_j_ kisutch obtained from the northern region were observed to have empty stomachs while the gut contents of the f i s h obtained i n the southern region are shown i n Table 5.7. Table 5.6 Prey groups u t i l i z e d by kisutch per i n d i v i d u a l specimen during JUly and August, 1987. Fish # 1 2 3 4 5 6 7 8 9 10 Number of Prey Items Amph. 376 11 40 12 24 19 Chaet. Euph. 4 244 71 172 96 23 17 12 25 Fish 14 3 1 5 3 4 Crab Megalopae 187 85 5 7 2 Zoeae 13 44 4 Ctenophora Polycheata Copepoda 82 26 Misc. (+ or -) + + - - - - - - -N.B. A l l northern specimens, n=10 contained no prey items while an a d d i t i o n a l 3 specimens from the southern region also had empty stomachs. 122 Table 5.7 Summary of e l e c t i v i t y indices Prey Type % Ni Ingested % Ni Available E l e c t i v i t y Value Result Amphipoda 0.296 0.068 0.639 +selection Chaetognatha 0.008 0 random Euphausiia 0.408 0.152 0.426 +selection Misc. Larvae 0.32 0.004 1.736 +selection Ctenophora 0.011 0 random Polychaeta 0 random Copepoda 0.066 0.757 -1.06 avoidance 5.4 Discussion  5.41 Net Flow Analysis of the net flow values from a l l current meter deployments indicates that the net flow i n Lambert Channel i s i n a southerly d i r e c t i o n from March to August of 1986. Observations i n d i c a t e that the deep water flow (42 m) i s 2.0 cm.s"^ with the flow i n the region of the shallower depths (5 at 29 m and 1 at 23 m) being at 3.1 cm.s -* thus i n d i c a t i n g a net transport south i n Lambert Channel at these l e v e l s . U t i l i z i n g the mean v e l o c i t y at the shallow meter p o s i t i o n s we obtain a net transport south of 2.7 km-d"*. In order to estimate the net transport i n the surface layer (top 15 m) examination of the mean current v e l o c i t y p r o f i l e vs depth (Figure 3.16) shows that the surface v e l o c i t i e s are on the order of twice the v e l o c i t i e s at the shallower 123 current meter deployment depth thus i n d i c a t i n g a possible net transport south of 5.4 km.d--'- for water mixed i n the region of Shingle S p i t . The estimate obtained for net transport assumes s i m i l a r current v e l o c i t y p r o f i l e s down channel from the current meter deployments, and at each s t a t i o n as well as no difference between the net flow rates and d i r e c t i o n between st a t i o n s . If these assumptions are v a l i d i t may be concluded that net transport i s south. The amplitude of the transport south w i l l vary somewhat from the given estimate due to the e f f e c t s of wind on the surface layer and v a r i a t i o n of current v e l o c i t i e s i n the Channel due to width and depth of the Channel. 5.42 Zooplankton D i s t r i b u t i o n The d i s t r i b u t i o n of the various zooplankton groups, North and South of Hornby Island i s obviously extremely v a r i a b l e , with s i g n i f i c a n t differences for a l l groups evidenced at the south end of Lambert Channel and Hornby Island at south s t a t i o n 1. The region south of Hornby Island and Lambert Channel, south s t a t i o n 1 i n general e x h i b i t s a higher density of a l l groups sampled, as well as a transport of the organisms south away from s t a t i o n 1. The transport away from south s t a t i o n 1 i s to the south,in the d i r e c t i o n of the net flow i n Lambert Channel as determined i n t h i s study. The high d e n s i t i e s of organisms observed at s t a t i o n 1, could be a r e s u l t of the transport of the increased primary production due to the mixing o f f Shingle S p i t . 124 V e r t i c a l l y migrating organisms would be observed i n higher d e n s i t i e s i n areas such as south s t a t i o n 1, which i s the c l o s e s t s t a t i o n downstream from the mixing event with enough depth to enable v e r t i c a l migration. These organisms may be i n high d e n s i t i e s i n t h i s region due to increased secondary production r e s u l t i n g i n enhanced food concentrations or due to some undetermined aggregating mechanism. 5.43 Resource U t i l i z a t i o n The u t i l i z a t i o n of the high d e n s i t i e s of zooplankton e x i s t i n g south of Lambert Channel by organisms further up the food chain could be r e a d i l y examined through the u t i l i z a t i o n of purse seines and trawls i n t h i s region as well as through determination of feeding p e r i o d i c i t y and d a i l y r a t i o n . Unfortunately such sampling was beyond the scope of t h i s study. Sport caught adult salmonids (0. kisutch) were a v a i l a b l e and the examination of gut contents i n d i c a t e s e l e c t i o n for amphipods, euphausiids, crab zoeae and megalopae as well as l a r v a l and juvenile f i s h . The u t i l i z a t i o n of these e l e c t i v i t y indices assumes that the 0. kisutch obtained the organisms contained i n t h e i r guts i n the region of capture as well as that prey species captured by the net are i n d i c a t i v e of the prey a v a i l a b l e to the predators. Considering the swimming speed and migratory behavior of 0. kisutch and escape reactions of zooplankton from the net t h i s i s a questionable assumption. I t does seem p l a u s i b l e that the f i s h obtained i n the southern region were u t i l i z i n g the high zooplankton density found around stations 125 1, and 2. The most popular s i t e for sport f i s h i n g around Hornby and Denman Islands exists at south s t a t i o n 1, and 2 and u t i l i z a t i o n of the increased zooplankton d e n s i t i e s observed conforms with the theory of patch u t i l i z a t i o n by f i s h (eg. Ivlev, 1961; Lasker, 1975; Vlymen, 1977; Hunter, 1981; F i e l d l e r and Bernard, 1987). A d d i t i o n a l support for u t i l i z a t i o n of the aggregations of zooplankton observed i s the lack of prey items i n the stomachs of specimens obtained at the northern end of Lambert Channel and Hornby Island i n low d e n s i t i e s of zooplankton. P a r t i c l e s found i n the gut samples of the 0. kisutch obtained i n t h i s study may not be completely i n d i c a t i v e of the prey items a c t u a l l y captured for reasons other than immigration and emigration of the salmonids. Persson (1979) noted a l i n e a r r e l a t i o n s h i p between the presence of an exoskeleton and the time required for digestion while LeBrasseur and Stevens (1965) also observed that the presence of an exoskeleton increases digestion times and therefore duration i n the gut. They determined the rate of digestion by salmon from fas t e s t to slowest as follows: 1) f i s h , 2) squid, 3) copepods, and 4) euphausiids. Macdonald (1982) and Jobling (1986) determined that the rate of di g e s t i o n i s enhanced by the r e l a t i v e surface area exposed to the d i g e s t i v e enzymes of the gut. Thus organisms of l e s s e r volume and greater surface area are digested more ra p i d l y , reducing t h e i r residence time i n the gut, although the degradation rate w i l l also be affected by the surface 126 c h a r a c t e r i s t i c s of the prey item and the rate of enzymatic a c t i v i t y (LeBrasseur and Stevens, 1965). 5.5 Conclusions The south end of Lambert Channel and Hornby Island i n t h i s study has shown a s i g n i f i c a n t increase i n major zooplankton group biomass, with no appreciable differences i n copepod species d i v e r s i t y i n the region examined. The increases i n zooplankton densities may i n part be due to the f i n e - s c a l e increases i n n i t r a t e + n i t r i t e concentrations and the subsequent increases i n primary production (Chapter 4) associated with the mixing event i n Lambert Channel. The increases i n primary production from the mixing event are transported south due to the net transport i n the channel. The transport of new production to the south end of Hornby Island and Lambert Channel may be of greater importance on the f i n e - s c a l e as the season progresses due to nutrient l i m i t a t i o n i n the surface waters and the re s u l t a n t decreases i n primary production (Parsons, 1979). The re s u l t a n t f i n e -scale patchiness should lead to an increase i n secondary production south of Lambert Channel. Unfortunately techniques are as yet unavailable to l i n k f i n e - s c a l e primary production such as i s evidenced here to downstream secondary u t i l i z a t i o n . Alternate mechanisms may i n part lead to the increases i n standing stock of zooplankton i n the region. V e r t i c a l l y migrating zooplankton may be advected over shallow 127 topography and migrate down slope thus increasing d e n s i t i e s along the slope (Boehlert and Seki, 1984; Genin et a l . , 1988; Mackas, pers. comm.). The aforementioned mechanism seems u n l i k e l y as the net flow i s to the south i n the surface waters as determined i n t h i s study. Net transport south would cause aggregations of zooplankton at the south end of Lambert Channel and Hornby Island to be advected to deeper water further south. The deep water transport i n the region i s also to the south as determined by Crean (pers. comm.) thus eliminating the i n f l u x of v e r t i c a l l y migrating zooplankton being advected in t o the region due to shallow depths i n Lambert Channel. Aggregative eddies i n the lee of topographic features can also lead to increased'densities of zooplankton (Uda and Ishino, 1958; Emery, 1972; Alldredge and Hamner, 1980; Hamner and Hauri, 1981; Wolanski and Hamner, 1988). South of Hornby Island and Lambert Channel generated eddies would move counterclockwise, and be dis p e r s i v e rather than aggregative due to the C o r i o l i s force causing an a c c e l e r a t i o n to the r i g h t i n the northern hemisphere, thereby causing a net motion out of the eddy i n the surface layers (Pond and Pickard, 1983). The negation of topographic e f f e c t s on migration, and aggregative eddies as mechanisms fo r enhanced d e n s i t i e s of zooplankton means that aggregations are probably due to behavioral patterns or possibly some other ph y s i c a l aggregating mechanism. Future studies should examine the 128 causes of t h e s e anomalous a g g r e g a t i o n s . The l i n k i n g of salmonid f e e d i n g t o the a g g r e g a t i o n of zooplankton e v i d e n c e d here i s at best tenuous due t o h i g h swimming speeds of the salmonids e n a b l i n g them t o s e a r c h l a r g e areas and immigrate i n t o the r e g i o n w i t h prey items a l r e a d y i n t h e i r stomachs. That the salmon are i n f a c t u t i l i z i n g zooplankton found i n abundance i n the r e g i o n of south s t a t i o n 1, i s of importance as the p o s s i b i l i t y e x i s t s t h a t these salmonids are a c t u a l l y u t i l i z i n g i n c r e a s e s i n secondary p r o d u c t i o n due t o the mixing i n Lambert Channel. The salmonids may be o r i e n t i n g t o the patchy d i s t r i b u t i o n of t h e i r prey caused by mixing i n Lambert Channel t o maximize consumption and t h e r e b y i n c r e a s e s u r v i v a l . The optimum u t i l i z a t i o n of patchy prey d i s t r i b u t i o n s has been documented f o r a number of f i s h s p e c i e s as w e l l as b e i n g p a r t of the f o r a g i n g t h e o r y l i t e r a t u r e (eg. I v l e v , 1961; Hunter and Thomas, 1973; L a s k e r , 1975; Gibson and E z z i , 1985; Lima, 1988) . D e n s i t i e s of zooplankton r e s u l t i n g a t the south end of Hornby and Lambert Channel should a l s o l e a d t o i n c r e a s e s i n s u r v i v a l and growth of p l a n k t i v o r o u s f i s h . The Lambert Channel r e g i o n i s one of the major spawning s i t e s f o r the p l a n k t i v o r o u s P a c i f i c h e r r i n g i n the S t r a i t of G e o r g i a (Robinson, 1988) and t h i s area may serve as a n u r s e r y a r e a s i t e f o r l a r v a and j u v e n i l e s . H e r r i n g may be u t i l i z e d as prey items a t the south end of Hornby and Lambert Channel by salmonids. I t i s p o s s i b l e t h a t they may c o n s t i t u t e a p o r t i o n lmonids. I t i s p o s s i b l e t h a t they may c o n s t i t u t e a p o r t i o n the u n i d e n t i f i e d f i s h p a r t s i n the guth samples examined. CHAPTER 6  General D i s c u s s i o n Fine-scale i n j e c t i o n of nutrient r i c h deep water due to t i d a l l y induced mixing o f f Shingle Spit has been shown to cause a s i g n i f i c a n t increase i n primary production i n the euphotic zone. If new nutrients remain i n the euphotic zone, the increase i n primary production w i l l r e s u l t i n an increase i n secondary production by grazers. Increased primary production on the f i n e - s c a l e should r e s u l t i n an increase i n d e n s i t i e s of herbivores on the coarse-scale leading to an increase i n production i n higher trophic l e v e l s . A mean increase of new primary production observed of 1.0 xlO kg.d i n June and July, 1986 (ranges from 0.2x10 to 3.2x10^ kg.d ) could a f f e c t an increase i n secondary production of at least 20 % (Parsons et a l . 1979), or 1.2x10 kg of secondary production with possible increases of 30 to 45 % of the increase i n primary production (Mullen and Brooks, 197 0) over ambient production i n June and July, 1986. (The primary production estimate does not take i n t o account added increased primary production due to excretion of nutrients by secondary and t e r t i a r y consumers a f t e r the i n i t i a l u t i l i z a t i o n . ) If these increases are being u t i l i z e d by predators such as salmonids or P a c i f i c herring i n the region, and we can assume an e c o l o g i c a l e f f i c i e n c y between 10 and 15 % (Parsons et a l . 1983), an increase i n biomass of these species could be 131 obtained of 150 kg (mean of 12.5 %) during June and July, 1986. The importance of the increase i n secondary production i s that i t occurs i n times of nutrient l i m i t a t i o n and therefore reduced production i n the bulk of the S t r a i t of Georgia (areas unaffected by mixing). The period of nutrient l i m i t a t i o n i n the summer i s a c r i t i c a l period i n the seaward migration of j u v e n i l e salmonids as well as being c r i t i c a l for s u r v i v a l of juvenile herring. Slow growth rates w i l l allow predation to reduce s u r v i v a l rates thereby a f f e c t i n g s u r v i v a l of the year c l a s s (Parsons et a l . 1983). By u t i l i z i n g regions of enhanced production and higher d e n s i t i e s of food resources on the coarse-scale, such as the region south of Hornby Island and Lambert Channel, increased growth rates w i l l r e s u l t i n enhanced s u r v i v a l of i n d i v i d u a l s . The fate of populations may also depend on the f i e l d of patchiness occurring (Haury et a l . 1978). Possible evidence of u t i l i z a t i o n of the resultant coarse-scale patchiness i s the existence of concentrations of juvenile salmonids south of Lambert Channel (Groot et a l . 1985). These predators would be i n p o s i t i o n to u t i l i z e increased production due to the mixing events, as net flow i s from the mixing events to the south end of Hornby Island and Lambert Channel. A great deal of recent research regarding s u r v i v a l of early l i f e h i s t o r y stages of commercial f i s h stocks has examined the theory of l a r v a l retention areas ( l i e s and 132 1984; S i n c l a i r and l i e s , 1985; S i n c l a i r , 1988). These l a r v a l r e t e n t i o n areas are defined as p a r t i c u l a r p h y s i c a l oceanographic locations i n which the larvae and juveniles are retained ( l i e s and S i n c l a i r , 1982; Gagne and 0'Boyle, 1984; S i n c l a i r , 1988). These physical oceanographic lo c a t i o n s must also have s p e c i f i c b i o l o g i c a l c h a r a c t e r i s t i c s conducive to the s u r v i v a l of l a r v a l and j u v e n i l e f i s h . S i n c l a i r (1988) states that "good retention areas lead to s i t u a t i o n s where herring can spawn i n spring and metamorphose within an acceptable seasonal envelope vs s i t u a t i o n s where the growth conditions are poorer and the l a r v a l phase must be longer causing the population to spawn e a r l i e r (winter or autumn spawning) to allow the young to metamorphose i n an appropriate period". These good retention regions must be regions of high b i o l o g i c a l production driven by the p h y s i c a l oceanography of the region. Permanent oceanographic features r e s u l t i n g i n increased production, may provide r e f u g i a from seasonal v a r i a t i o n s caused by c l i m a t i c v a r i a t i o n , ensuring a baseline s u r v i v a l rate of the various species incorporated. Regions such as the southern end of Hornby Island and Lambert Channel with a permanent t i d a l l y driven mixing event may be c r i t i c a l f o r s u r v i v a l of f i s h e r i e s stocks such as the P a c i f i c herring i n years of poor conditions elsewhere i n the S t r a i t . The existence of t h i s t i d a l l y driven mixing event may explain why the Hornby Denman region i s the s i t e of the major spawning stock i n the S t r a i t of Georgia (Robinson 1988). 133 Var i a t i o n s i n densities of planktonic organisms have been a t t r i b u t e d to the aggregative properties of eddies i n the lee of i s l a n d s , s p i t s and reefs (Emery 1972; Hamner and Hauri 1981; Zeldis and J i l l e t 1982; Bowman et a l . 1983; Foster and Battaerd 1985; Lobel and Robinson 1986; Zavodnik 1987) and high d e n s i t i e s i n major f i s h e r i e s stocks have been observed to e x i s t i n some of these areas. U t i l i z a t i o n of increased d e n s i t i e s of aggregated zooplankton has been implied for many of these aggregating events (Uda and Ishino 1958; Emery 1972; Bowman et a l . 1983; Lobel and Robinson 1986). In a l l of these regions, topographic features should cause v a r i a t i o n s i n flow patterns and nutrient additions due to t i d a l l y induced mixing. A proportion of the new nutrients should be entrained into the downstream aggregative eddies created i n the lee of topographic features thus causing an increase i n primary and secondary production. The resultant increase i n primary and secondary production (dependant on the scale) should lead to possible nursery s i t e s f o r the various species i n the area. The e f f e c t s of physical phenomena on l i g h t l e v e l s , n utrients and s t a b i l i t y i n the marine ecosystem l i m i t b i o l o g i c a l a c t i v i t i e s i n the marine environment through enhancement or reduction of primary production. Determination of the e f f e c t s of p h y s i c a l phenomena on primary production and t r a n s f e r up the food web w i l l enable estimation of the carrying capacity of marine ecosystems. Determination of the u t i l i z a t i o n of increased production should lead to a more adequate understanding of the factors l i m i t i n g f i s h e r i e s production. If as stated by Longhurst (1981) aggregation i s a necessary condition of l i f e i n the oceans and an i n e v i t a b l e consequence of the ph y s i c a l environment, increased s u r v i v a l of f i s h e r i e s stocks may well depend upon the degree of aggregation and production of prey species due to ph y s i c a l phenomena such as evidenced south of Shingle S p i t . The understanding of mechanisms causing anomalously high s u r v i v a l of f i s h year classes must be t i e d to conditions enabling increased s u r v i v a l . 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Appendix 1 154 Table:1 Zooplankton Densities South S t n . l , 1987 Plankton June 19 July 17 August 4 Grouping Mean S.E . n=3 Number (m ) Amph. 2.53xl0 3 2.91xl0 3 7.29xl0 3 5.59xl0 2 Chaet. 5.6xl0 2 3.6xl0 2 3.4xl0 2 6.7X101 Euph. 2.89xl0 3 4.93xl0 3 2.24xl0 3 2.19xl0 3 Crab 1.7xl0 3 3.8xl0 2 1.lxlO 1 2.6X101 Cten. 1.4xl0 2 7.6X101 3.0xl0 2 3.5X101 Poly. 2.8xl0 2 Cop. 3.86xl0 4 7.08xl0 4 6.95xl0 4 2.52xl0 4 T o t a l 4.67xl0 4 7.95xl0 4 9.99xl0 4 5.37xl0 3 Copepoda Major Species Composition (individuals.m ) A c a r t i a Sp. 7.2xl0 2 8.5xl0 3 7 .2xl0 2 Calanus Sp. 4 .OxlO 3 Centropages Sp. 2.8xl0 3 8 •9xl0 3 Metridia Sp. 2.8xl0 4 1.2xl0 4 5 .7xl0 4 Neocalanus Sp. 2.1x10 7.1xl0 3 Oithona Sp. 5.7xl0 3 Pseudocalanus Sp. 2.8xl0 4 1 .4xl0 3 Appendix 1 155 Table:2 Zooplankton Densities S o u t h S t n 2,1987 Plankton June 19 J u l y 17 A u g u s t 4 Grouping Number (m 2) Amphipoda 8 . 1 0 x l 0 2 4 . 8 9 x l 0 3 1 . 6 8 x l 0 3 C h a e t o g n a t h a 7.7x102 3.5x102 2 .3x102 E u p h a u s i i a 1 . 6 0 x l 0 3 8 . l O x l O 3 7 . 2 3 x l 0 3 Crab L a r v a e 1 . 3 4 x l 0 3 5 . 7 x l 0 3 C t e n o p h o r a 1 . l x l O 2 4 . 6 x l 0 2 2 . 3 x l 0 2 P o l y c h a e t a 7 . 0 X 1 0 1 Copepoda l. O O x l O 3 8 . 9 5 x l 0 4 1 . 5 6 x l 0 4 Total 1 . 4 7 x l 0 4 1 . 0 4 x l 0 4 2 . 5 0 x l 0 4 Copepoda Major Species Composition ( i n d i v i d u a l s . m ) A c a r t i a Sp. 1 . 4 x l 0 3 1 . 3 x l 0 4 4 . 6 x l 0 2 C a l a n u s Sp. 1 . 8 x l 0 4 5 . 3 x l 0 3 C e n t r o p a g e s Sp. 1 . 4 x l 0 3 M e t r i d i a Sp. 2 . 6 x l 0 3 2 . 0 x l 0 3 3 . O x l O 3 N e o c a l a n u s Sp. l . O x l O 3 2 . 7 x l 0 3 3 . 7 x l 0 3 O i t h o n a Sp. 3 . 2 x l 0 3 9 • 4 x l 0 2 P s e u d o c a l a n u s Sp . 3 . 4 x l 0 2 3 . 4 x l 0 2 4 . 7 x l 0 2 Appendix 1 156 Table:3 Zooplankton Densities South Stn 3, 1987 Plankton June 19 J u l y 17 August 4 Grouping Mean S.E. n=3 Number (m ) Amph. 2. 8 6 x l 0 3 4 . 2 7 x l 0 3 2 . 4 4 x l 0 3 1 . 8 7 x l 0 3 Chaet. 6 . 6 x l 0 2 1 . 7 x l 0 2 2 . 1 x l 0 2 Euph. 1 . 6 x l 0 3 6.7X10 1 8 . 0 x l 0 3 1.04xl0 4 Crab 2 . l x l O 3 4 . 7 x l 0 2 4 . 2 x l 0 2 Cten. 3 . 8 x l 0 2 3.8X10 1 2 . 5 x l 0 2 1 . 4 x l 0 3 P o l y . 4.6X10 1 Cop. 2 . 8 7 x l 0 4 1.53xl0 3 4.27xl0 4 3 . 0 9 x l 0 4 T o t a l 3 . 6 3 x l 0 4 1.57xl0 3 5 . 4 0 x l 0 4 4 . 4 6 x l 0 4 Copepoda Major S p e c i e s Composition ( i n d i v i d u a l s .m2) A c a r t i a Sp. 9 . 5 x l 0 2 1 • 3 x l 0 4 Calanus Sp. 1 . 3 x l 0 3 1 . 3 x l 0 4 Centropages Sp.2.0x10^ 2 . l x l O 3 M e t r i d i a Sp. 2 . 3 x l 0 4 6 • 2 x l 0 2 Neocalanus Sp. 2 . 6 x l 0 3 1 . 2 x l 0 4 O i t h o n a Sp. 1 . 7 x l 0 3 P s e u d o c a l . Sp. 3 . 8 x l 0 2 1 . 8 x l 0 4 4 • 9 x l 0 3 Tortanus Sp. 2 . 0 x l 0 2 1 . 3 x l 0 3 Appendix 1 157 Table: 4 Zooplankton Densities South Stn 4, 1987 Plankton June 19 J u l y 18 August 4 Grouping Number (m ) Amphipoda 3 . 7 x l 0 3 1 . 9 x l 0 3 1 . 3 x l 0 3 Chaetognatha 8 . 5 x l 0 2 2 . 6 x l 0 2 7 . 2 X 1 0 1 E u p h a u s i i a 1.28xl0 3 6 . 2 8 x l 0 3 3 . 5 9 x l 0 3 Crab Larvae 8 . 5 x l 0 2 1 . 8 x l 0 2 Ctenophora 2 . 8 x l 0 2 3 . 9 x l 0 2 6 . 2 x l 0 2 P o l y c h a e t a 5 . l x l O 2 4.OxlO 1 Copepoda 2.38xl0 4 2 . 3 1 x l 0 4 3.28xl0 4 T o t a l 3.07xl0 4 3 . 2 7 x l 0 4 3.84xl0 4 Copepoda Major Species Composition ( i n d i v i d u a l s . A c a r t i a Sp. 8 . 3 x l 0 3 3.OxlO 3 Calanus Sp. 2 . 1 x l 0 3 1 . 8 x l 0 4 M e t r i d i a Sp. 2 . 7 x l 0 4 4 . 9 x l 0 3 5 . 9 x l 0 3 Neocalanus Sp. 5 . 9 x l 0 2 2 . 8 x l 0 3 4 . 6 x l 0 3 O i t h o n a Sp. 2 . 4 x l 0 3 Pseudocalanus Sp. 3 . 9 x l 0 3 Appendix 1 158 Table:5 Zooplankton Densities South Stn 5, 1987 Plankton June 19 J u l y 18 August 4 Grouping Number (m ) Amphipoda 1.84xl0 3 2 . 0 4 x l 0 3 Chaetognatha 1 . 3 x l 0 3 3.8X10 1 1 . 9 x l 0 2 E u p h a u s i i a 3 . l O x l O 3 2 . 8 3 x l 0 3 6 . 5 5 x l 0 3 Crab Larvae 2 . 2 5 x l 0 3 7 . 6 X 1 0 1 3 . 8 X 1 0 1 Ctenophora 1 . 4 x l 0 3 7 . 3 x l 0 2 P o l y c h a e t a 1 . 4 x l 0 2 7 . 7 X 1 0 1 Copepoda 4.41xl0 4 3.96xl0 4 2 . 2 5 x l 0 4 Total 5.22xl0 4 4.43xl0 4 3 . 2 1 x l 0 4 Copepoda Major Species Composition ( i n d i v i d u a l s . m ) A c a r t i a Sp. 7 . 5 x l 0 3 2 . 8 x l 0 3 1 . 4 x l 0 3 Calanus Sp. 2 . 4 x l 0 3 4 . 1 x l 0 3 Centropages Sp 8 . 3 x l 0 2 1 . 4 x l 0 3 M e t r i d i a Sp. 2 . 1 x l 0 4 9 . 5 x l 0 3 2.OxlO 3 Neocalanus Sp. 6 . 7 x l 0 3 9 . l x l O 2 Oithona Sp. 1 . 2 x l 0 4 1 . 6 x l 0 3 Pseudocalanus Sp. 1 . 7 x l 0 3 1.3xl0 4 9 . 3 x l 0 3 A p p e n d i x 1 159 Table : 6 a Zooplankton Densities S o u t h S t n 6, 1987 Plankton J u n e 19 J u l y 18 A u g u s t 2 Grouping Mean S.E. Mean S.E. Mean S.E. n=3 n=3 n=3 Number (m 2) Amph. 2 . 0 2 x l 0 3 3.84X10 1 3 . 3 6 x l 0 3 3 . 4 3 x l 0 2 5 • 2 0 x l 0 3 1 . 0 8 x l 0 2 C h a e t . 4 . 7 x l 0 2 l . O x l O 2 1 . 5 x l 0 3 3 . 2 x l 0 2 1 • 2 x l 0 2 5.0x10° E u p h . 7 . 7 x l 0 2 1 . 4 x l 0 2 3 . 4 7 x l 0 3 3 . 9 2 x l 0 2 9 • 7 7 x l 0 3 1 . 5 8 x l 0 2 C r a b 1 . 1 3 x l 0 3 2 . 6 6 x l 0 2 3 . 2 x l 0 2 4.4X10 1 7 .6X101 l . O x l O 1 C t e n . 2 . 8 x l 0 2 6.7X10 1 1 . 3 x l 0 3 2 . 5 x l 0 2 1 . 9 x l 0 2 6x10° P o l y . 3 . 3 x l 0 2 7.7X10 1 C o p . 3 . 1 7 x l 0 4 2 . 3 9 x l 0 3 8.61xl0 3 1 . 2 4 x l 0 3 1 . 7 1 x l 0 4 2 . 8 8 x l 0 2 Total 3 . 6 7 x l 0 4 3 . 0 7 x l 0 3 1 . 8 6 x l 0 4 2 . 5 6 x l 0 3 3 . 2 4 x l 0 4 5 . 7 7 x l 0 2 Appendix 1 160 Table :6b Zooplankton Densities South Stn 6, 1987 June 19 J u l y 18 August 2 Copepoda Major Species Composition 9 ( i n d i v i d u a l s . m ) A c a r t i a Sp. 2 . 8 x l 0 3 6 . 8 x l 0 2 2 . 9 x l 0 2 Calanus Sp. 8.4x10^ 2.OxlO 3 Centropages Sp. 5 . 7 x l 0 2 5 . 5 x l 0 2 M e t r i d i a Sp. 2 . 9 x l 0 4 8 . l x l O 3 Neocalanus Sp. 1 . 9 x l 0 3 2 . 2 x l 0 3 3 . 5 x l 0 3 Oithona. Sp. 6 . 4 x l 0 3 1 . 5 x l 0 2 Pseudocalanus Sp. 3 . 5 x l 0 3 3 . 7 x l 0 3 1.3xlO J Tortanus Sp. _ 2 . 6 x l 0 2 1 . 2 x l 0 2 9 . 8 x l 0 2 Appendix 1 161 Table:7 Zooplankton Densities South Stn. 7, 1987 Plankton June 19 July 18 August 4 Grouping Number (m ) Amphipoda 2.2xl0 3 3.4xl0 2 3.2xl0 3 Chaetognatha 4.6xl0 2 1.7xl0 2 7.6X10 1 Euphausiia 2.1xl0 3 1.9xl0 3 5.9xl0 3 Crab Larvae 1.7xl0 3 1.5xl0 2 3 . 1 X 1 0 1 Ctenphora 2.8xl0 2 7.3xl0 2 9.6xl0 2 Copepoda 1.12xl0 4 9.86xl0 3 2.52xl0 4 T o t a l 1.72xl0 4 1.31xl0 4 3.53xl0 4 Copepoda Major Species Composition (i n d i v i d u a l s ) A c a r t i a Sp. 1.9xl0 2 7.9xl0 2 Calanus Sp. 1.2xl0 3 9.6xl0 3 Centropages sp. 7.6xl0 2 M e t r i d i a sp. 4.3xl0 3 1.6xl0 3 2.3xl0 3 Neocalanus Sp. 1.9xl0 2 2.3xl0 3 1 . l x l O 4 Oithona Sp. 3.4xl0 3 Pseudocalanus Sp. 4.0xl0 3 5.0xl0 2 Tortanus Sp. 1.9xl0 2 7.6xl0 2 Appendix 1 162 Table:8 Zooplankton Densities South Stn. 8, 1987 Plankton June 19 J u l y 18 August 4 Grouping 9 Number (irr) Amphipoda 3 . 9 x l 0 2 1 . 8 x l 0 3 7 . 3 x l 0 2 Chaetognatha 7 . 4 x l 0 2 6 . 4 x l 0 2 4.3X10 1 E u p h a u s i i a 4 . 8 x l 0 2 5 . 1 x l 0 3 2 . 4 x l 0 3 Crab Larvae 3 . 5 x l 0 2 3 . 4 x l 0 2 Ctenophora 2 . 1 x l 0 2 6 . 0 x l 0 2 3 . 4 x l 0 2 Copepoda 7.67xl0 3 2 . 6 5 x l 0 4 1.91xl0 4 T o t a l 9.85xl0 3 3 . 4 9 x l 0 4 2 . 2 6 x l 0 4 Copepoda Major Species Composition ( i n d i v i d u a l s . m ) A c a r t i a Sp. 4 . 3 x l 0 2 2 . 6 x l 0 3 1 . 7 x l 0 3 Calanus Sp. 9 . 0 x l 0 3 7 . 8 x l 0 3 Centropages Sp. 1 . l x l O 2 M e t r i d i a Sp. 2 . 7 x l 0 3 5 . 8 x l 0 3 1 . 9 x l 0 3 Neocalanus Sp. 1 . l x l O 2 3 . 7 x l 0 3 7 . 1 x l 0 3 O i t h o n a Sp. 1 . 4 x l 0 3 7 . 9 x l 0 2 Pseudocalanus Sp. 3 . 2 x l 0 2 3 . 2 x l 0 3 5 . 7 x l 0 2 T o r t a n u s Sp. 3 . 2 x l 0 2 Appendix 1 163 Table:9 Zooplankton Densities South Stn. 9, 1987 Plankton June 19 J u l y 18 August 4 Grouping Number (m ) Amphipoda 2 . 9 6 x l 0 3 2 . 5 6 x l 0 3 5 . 6 1 x l 0 3 Chaetognatha 4 . 2 x l 0 2 1 . 3 x l 0 2 7.6X10 1 E u p h a u s i i a l . O x l O 3 1.64xl0 3 1.02xl0 4 Crab Larvae 5 . 6 x l 0 2 1 . 9 x l 0 2 Ctenohora 3 . 5 x l 0 2 2 . 7 x l 0 2 4 . 6 x l 0 2 Copepoda 1.54xl0 4 1.30xl0 4 4 . 7 9 x l 0 4 Total 2 . 0 7 x l 0 4 1.78xl0 4 6.43xl0 4 Copepoda Major Species Composition ( i n d i v i d u a l s.icr) A c a r t i a Sp. 1 . 7 x l 0 3 2 . 4 x l 0 3 3 . 8 x l 0 3 Calanus Sp. 4 . 2 x l 0 3 8 . 6 x l 0 3 M e t r i d i a Sp. 5 . 5 x l 0 3 7 . 8 x l 0 2 4 • 3 x l 0 3 Neocalanus Sp • 2 . 5 x l 0 3 1 . 5 x l 0 4 O i t h o n a Sp. 4 . 3 x l 0 3 Pseudocalanus Sp. 2 . 4 x l 0 2 2 . 9 x l 0 3 1 . 6 x l 0 4 Tortanus Sp. 2 . 4 x l 0 2 Appendix 1 164 Table:10 Zooplankton Densities South S t n . 10, 1987 Plankton June 19 J u l y 18 August 4 Grouping Number (m ) Amphipoda 1.83xl0 3 3 . 5 2 x l 0 3 5 . 2 4 x l 0 3 Chaetognatha 9 . 9 x l 0 2 1 . 8 x l 0 3 E u p h a u s i i a 2.02xl0 3 4 . 0 5 x l 0 3 1.19xl0 4 Crab Larvae 7 . 0 x l 0 2 9 . 3 x l 0 2 1 . 5 x l 0 2 Ctenophora 8 . 4 x l 0 2 3 . l x l O 2 7.6X10 1 Copepoda 3.61xl0 4 4 . 4 2 x l 0 4 4.48xl0 4 T o t a l 4.24xl0 4 5 . 5 6 x l 0 4 6.25xl0 4 Copepoda Major Species Composition ( i n d i v i d u a l s . m ) A c a r t i a Sp. 5 . 7 x l 0 2 4 . 5 x l 0 3 1 . 3 x l 0 3 Calanus Sp. 1 • 4 x l 0 4 4 . 5 x l 0 3 Centopages Sp. 1 . l x l O 3 4 . l x l O 3 M e t r i d i a Sp. 2 . 3 x l 0 4 9 .OxlO 2 Neocalanus Sp. 5 . 7 x l 0 2 4 . l x l O 3 1 . 5 x l 0 4 O i t h o n a Sp. 3 . 4 x l 0 3 9 .OxlO 2 Pseudocalanus Sp. 5 . 7 x l 0 2 1 . 4 x l 0 4 1 • 9 x l 0 4 Appendix 1 165 Table:11 Zooplankton Densities South S t n . 11, 1987 Plankton June 19 J u l y 18 August 4 Grouping Mean S .E. n=3 Number (m ) Amph. 1.97xl0 3 3.17xl0 2 1 . 8 0 x l 0 3 2 . 9 4 x l 0 3 Chaet. 7 . 5 x l 0 2 l . l x l O 2 3 . 8 x l 0 2 2 . 7 x l 0 2 Euph. 1.02xl0 3 3.71xl0 2 1 . 8 2 x l 0 2 8.71xl0 3 Crab 4 . 7 6 x l 0 2 1.92X10 1 3 . 4 x l 0 2 1 . 2 x l 0 2 Cten. 6 . 8 x l 0 2 5 . 1 X 1 0 1 2.OxlO 2 3 . l x l O 2 Cop. 1.16xl0 4 3.15xl0 2 2 . 4 0 x l 0 4 3.68xl0 4 T o t a l 1.65xl0 4 7.03xl0 2 2 . 8 0 x l 0 4 4.92xl0 4 Copepoda Major Species Composition 9 ( i n d i v i d u a l s .m"') A c a r t . Sp. 6 . 2 x l 0 2 3 .OxlO 3 1 . l x l O 3 C a l . Sp. 4 .OxlO 3 8 . 8 x l 0 3 Cent. Sp. 9.8X10 1 9 . 9 x l 0 2 Met. Sp. 2 . 7 x l 0 3 3 .OxlO 3 1 . 5 x l 0 3 Neoc. Sp. 1 . 5 x l 0 2 2 .OxlO 3 1 . 7 x l 0 4 O i t h . Sp. 3 . 5 x l 0 3 7 . 4 x l 0 2 Pseudoc Sp. 6 . 7 x l 0 2 8 . 4 x l 0 3 7 .OxlO 3 T o r t . Sp. 1 . 7 x l 0 2 Appendix 1 166 T a b l e : 1 2 Zooplankton Densities South Stn. 12, 1987 Plankton June 19 J u l y 18 August 4 Grouping Number (m ) Amphipoda 1 . 7 x l 0 3 2 . 7 x l 0 3 5 . 2 0 x l 0 3 Chaetognatha 8 . l x l O 2 3 . 4 x l 0 2 7.6X101 E u p h a u s i i a 8 . 9 x l 0 2 1.5 x l O 3 4 . 8 x l 0 3 Crab Larvae 2 . 5 x l 0 2 8.6X101 Ctenophora 4 . 2 x l 0 2 8.6X101 2.4X10 1 Copepoda 9.33xl0 3 3.12xl0 4 1.55xl0 4 Total 1.33xl0 4 3 . 5 9 x l 0 4 2 . 5 6 x l 0 4 Copepoda Major Species Composition ( i n d i v i d u a l s . m ) A c a r t i a Sp. 9 . l x l O 2 1 . 3 x l 0 4 Calanus Sp. 2 . 2 x l 0 3 3 . 6 x l 0 3 M e t r i d i a Sp. 2 . 9 x l 0 3 1 . 7 x l 0 3 Neocalanus Sp. 1. 5 x l 0 2 9 . 4 x l 0 3 O i t h o n a Sp. 2 . 2 x l 0 3 2 . 8 x l 0 3 , Pseudocalanus Sp. 1. 2 x l 0 3 1 . 2 x l 0 4 7 . 7 x l 0 2 Tortanus Sp. 3.OxlO 2 Appendix 1 167 Table:13a Zooplankton Densities South Stn. 13, 1987 Plankton Grouping June 19 J u l y 18 August 4 Mean S. E. n=3 Mean S.E. n=3 Number (m ) Amphipoda 1 . 6 x l 0 3 6. 6 x l 0 2 2.8X10 1 3 . 3 x l 0 3 3.OxlO 2 Chaetognatha 7.4x10° 2.7x10° 4 . 2 x l 0 2 1. Ox l O 2 9.3X10 1 E u p h a u s i i a 1.13xl0 3 8. OxlO 2 6.4X10 1 2 . 3 6 x l 0 3 1 . 4 6 x l 0 2 Crab Larvae 4 . 2 x l 0 2 3. 6.3x10° 1.5x10° OxlO 2 1.4X10 1 Ctenophora 5 . 6 x l 0 2 1. 6 x l 0 2 2.OxlO 1 3 . 7 x l 0 2 2.5X10 1 Copepoda 1.68xl0 4 1. 5 1 x l 0 3 2.59X10 1 2 . 0 5 x l 0 4 5 . 8 3 x l 0 2 Total 2 . 1 0 x l 0 4 3. 5 5 x l 0 3 1.58xl0 2 2 . 6 6 x l 0 4 1.06xl0 3 Appendix 1 168 Table:13b Zooplankton Densities South Stn. 13, 1987 Copepoda Major Species Composition June 19 July 18 August 4 (individuals.m ) A c a r t i a Sp. 2.1xl0 3 3.9xl0 2 1.5xl0 3 Calanus Sp. 3.3xl0 2 2.7xl0 3 Centropages Sp. 2.3xl0 2 Metridia Sp. 5.3xl0 3 8.2xl0 2 Neocalanus Sp. 2.6xl0 2 2.4xl0 2 l . l x l O 4 Oithona Sp. 3.2xl0 3 5.9X101 Pseudocalanus Sp. 1.3xl0 3 4.3xl0 2 3.5xl0 3 Tortanus Sp. l . l x l O 3 3.3X101 1.9xl0 2 Appendix 1 169 Table:14 Zooplankton D e n s i t i e s South S t n. 14, 1987 P l a n k t o n June 19 J u l y 18 August 4 Grouping Number (m ) Amphipoda 9 . 2 x l 0 2 1 . 5 x l 0 3 3 . 3 6 x l 0 3 Chaetognatha 3 . 2 x l 0 2 4 . 1 X 1 0 1 7.6x10 1 -E u p h a u s i i a 1.21xl0 3 9 . 8 x l 0 2 9.98xl0 3 Crab Larvae 7 . 4 x l 0 2 3 . 8 x l 0 2 Ctenophora 6 . 3 x l 0 2 1 . 2 X 1 0 1 l . O x l O 2 Copepoda 1.36xl0 4 1.79xl0 4 1.36xl0 4 T o t a l 1.74xl0 4 2 . 0 8 x l 0 4 2 . 7 1 x l 0 4 Copepoda Major S p e c i e s Composition ( i n d i v i d u a l s . m ) A c a r t i a Sp. 2 . 7 x l 0 2 7 . 1 x l 0 3 2 . 7 x l 0 2 Calanus Sp. 6.OxlO 3 1 . 9 x l 0 3 Centropages Sp. 9 . l x l O 2 1 . 4 x l 0 2 M e t r i d i a Sp. 9 . 5 x l 0 3 1 . 6 x l 0 3 Neocalanus Sp. 6 . l x l O 3 O i t h o n a Sp. 3 . 3 x l 0 3 Pseudocalanus Sp. 2 . 7 x l 0 2 2 . 9 x l 0 3 2 . 5 x l 0 3 Tortanus Sp. 2 . 7 x l 0 2 5 . 5 x l 0 2 5 . 5 x l 0 2 Appendix 1 170 Table:15 Zooplankton Densities South Stn. 15, 1987 Plankton June 19 Grouping Mean S .E. n=3 Number (m ) Amphipoda 1.39xl0 3 1 , 5 7 x l 0 2 Chaetognatha 4 . 3 x l 0 2 4 .8X101 Euphausiia 6.8xl0 2 1 . l x l O 2 Crab Larvae 2 . 2 x l 0 2 6 . 3 X 1 0 1 Ctenophora 5 . 6 x l 0 2 5 .OxlO 1 Copepoda 7.24xl0 3 3 . 6 5 x l 0 2 Total 1.05xl0 4 5 . 5 9 x l 0 2 Copepoda Major Species Composition 9 (individuals.m ) A c a r t i a Sp. 9 . 4 x l 0 2 Metridia Sp. 2 . 6 x l 0 3 Neocalanus Sp. 1.6xl0 2 Oithona Sp. 1 . 2 x l 0 3 Pseudocalanus Sp. 7 . 2 x l 0 2 Tortanus Sp. 4 . 2 x l 0 2 Appendix 1 171 Table:16 Zooplankton D e n s i t i e s North S t n , l 1987 P l a n k t o n June 19 J u l y 20 August 5 Grouping Number (m ) Amphipoda 2 . 4 x l 0 2 3 . 8 x l 0 2 4 . 2 x l 0 2 Chaetognatha 6 . 2 X 1 0 1 1.4X101 3.8X10 1 E u p h a u s i i a 1 . l x l O 2 2 . 9 x l 0 2 1 . l x l O 3 Crab Larvae 3.5X10 1 7.6X10 1 3 . 4 x l 0 2 Ctenphora 8.8X10 1 8.6X10 1 7.6X10 1 Copepoda 2.46xl0 3 2 . 2 3 x l 0 3 3 . 4 4 x l 0 3 T o t a l 3.00xl0 3 3 . 0 8 x l 0 3 5 . 3 9 x l 0 3 Copepoda Major S p e c i e s Composition ( i n d i v i d u a l s . m ) A c a r t i a Sp. 2 . 9 x l 0 2 2 . 7 x l 0 2 2 .OxlO 2 Calanus Sp. 0 8 . 3 x l 0 2 1 . 8 x l 0 3 M e t r i d i a Sp. 1.4xl0 3 6 . 5 x l 0 2 3 . l x l O 2 Neocalanus Sp. 9.7X10 1 1 . 4 x l 0 2 1 . 2 x l 0 3 O i t h o n a Sp. 3 . 9 x l 0 2 1 . 3 x l 0 2 Pseudocalanus Sp. 2 . 4 x l 0 2 2 . 2 x l 0 2 T o r t a n u s Sp. 2 . 4 x l 0 2 Appendix 1 172 Table:17 Zooplankton Densities North Stn. 2, 1987 Plankton June 19 July 20 August 5 Grouping Number (m ) Amphipoda 1.8xl0 2 2.7xl0 2 5 .OxlO 2 Chaetognatha 1.8X101 2.9X101 Euphausiia 1.8xl0 2 3.5xl0 2 3 .79x10 3 Crab Larvae 7.OxlO 2 6.OxlO 1 5 .4xl0 2 Ctenphora 7.9X101 1.6xl0 2 1 . l x l O 3 Copepoda 2.59xl0 3 2.84xl0 3 4 .85x10 3 To t a l 3.74xl0 3 3.71xl0 3 1 .10x10 4 Copepoda Major Species Composition (individuals.m ) A c a r t i a Sp. l.OxlO 3 3.4xl0 2 Calanus Sp. 1.2xl0 3 2 .7xl0 3 Metridia Sp. 3.6xl0 2 3.6xl0 2 8 •2xl0 2 Neocalanus Sp. 1.8xl0 2 8.8xl0 2 1 .4xl0 3 Oithona Sp. 2.4xl0 2 2.6X101 Pseudocalanus Sp. 4.8xl0 2 2.6X101 Tortanus Sp. 8.4xl0 2 2 . 2 X 1 0 1 Appendix 1 17 3 T a b l e :18a Zooplankton D e n s i t i e s North S t n . 3 , 1987 P l a n k t o n Grouping June 19 J u l y 20 August 5 Mean S.E. n=3 Mean S. E. n=3 Number (m ) Amphipoda 1 . 6 x l 0 2 3 . 4 . X 1 0 1 2 . 1 x l 0 2 4 .6x10° 3 . 8 x l 0 2 Chaetognatha 1 . 8 x l 0 2 2.5X10 1 3.3X10 1 3 .8x10° 5 . 1 X 1 0 1 E u p h a u s i i a 1 . 4 x l 0 2 2.9X10 1 2 . 4 9 x l 0 2 4 .6x10° 1.4 9 x l 0 3 Crab Larvae 4 . 2 x l 0 2 2.8X10 1 9.6X10 1 6 .1x10° 1 . l x l O 2 Ctenophora 1 . 6 x l 0 2 3.5X10 1 l . l x l O 2 7 .6x10° 1 . 3 x l 0 3 Copepoda 7. 8 0 x l 0 3 3 . 7 2 x l 0 2 4 . 5 1 x l 0 3 8 . 1 2 X 1 0 1 1 . 7 2 x l 0 3 T o t a l 8.88 x l O 3 4 . 4 9 x l 0 2 5 . 2 1 x l 0 3 1 • 0 8 x l 0 2 5 . 0 7 x l 0 3 Appendix 1 174 Table :18b Zooplankton Densities North Stn. 3, 1987 Copepoda Major Species Composition June 19 July 20 August 5 (individuals.m) A c a r t i a Sp. 2.5xl0 3 3.OxlO 1 4.7X101 Calanus Sp. 3.OxlO2 2.7xl0 2 Centropages Sp. l . l x l O 1 2.7 xl0° 6.9X101 Metridia Sp. 1.5xl0 3 1.7xl0 2 Neocalanus Sp. 5.2xl0 2 5.9xl0 2 2.7xl0 2 Oithona Sp. 5.3xl0 2 4 . 2 X 1 0 1 Pseudocalanus Sp. 2.4xl0 3 9 . 2 X 1 0 1 6.7xl0 2 Tortanus Sp. 3.5xl0 2 1.7X101 4.7X101 Appendix 1 17 5 Table:19 Zooplankton D e n s i t i e s North Stn. 4, 1987 P l a n k t o n June 19 J u l y 20 August 5 Grouping Number (m Amphipoda 4 . 9 x l 0 2 3 . 3 x l 0 2 1 • 9 x l 0 2 Chaetognatha 7.OxlO 1 3.1x10 1 E u p h a u s i i a 4.OxlO 2 5.OxlO 2 1 . 7 6 x l 0 3 Crab Larvae 1 . 7 x l 0 2 2 . 2 X 1 0 1 3 •8X10 1 Ctenophora 3 . 2 x l 0 2 1 . 3 x l 0 2 2 • 7 x l 0 2 Copepoda 7.74xl0 3 3 . 9 7 x l 0 3 9 . 2 9 x l 0 3 T o t a l 9.20xl0 3 4 . 9 8 x l 0 3 1 . 1 5 x l 0 4 Copepoda Major S p e c i e s Composition ( i n d i v i d u a l s ) A c a r t i a Sp. 2 . 7 x l 0 3 6 . 4 x l 0 2 4 . 6 x l 0 2 Calanus Sp. 1 . 6 x l 0 3 3 . 6 x l 0 3 M e t r i d i a Sp. 2 . 2 x l 0 3 3 . 2 x l 0 2 1 . 8 x l 0 3 Neocalanus Sp. 6.3 x l 0 2 9 . 5 x l 0 2 3 . 4 x l 0 3 O i t h o n a Sp. 1.6xl0 3 Pseudocalanus Sp.9.5xl0 2 4 . 8 x l 0 2 Appendix 1 176 Table:20 Zooplankton Densities North Stn. 5, 1987 Plankton June 19 July 20 August 5 Grouping Number (m ) Amphipoda 9.2xl0 2 3.9xl0 2 1.07xl0 3 Chaetognatha 2.1xl0 2 3.6X101 3.8X101 Euphausiia 2.5xl0 2 4.4xl0 2 2.3xl0 3 Crab Larvae 4.7xl0 2 1.9X101 7.6X101 Ctenophora 1.8xl0 2 4.lxlO 1 1.2xl0 3 Copepoda 8.41xl0 3 6.58xl0 3 1.77xl0 4 Total 1.04xl0 4 7.51xl0 3 2.23xl0 4 Copepoda Major Species Composition (i n d i v i d u a l s .m2 ) A c a r t i a Sp. 3.OxlO 3 5.4xl0 2 Calanus Sp. 2.7xl0 3 3.8xl0 3 Metridia Sp. 4.OxlO 3 9.2xl0 2 1.3xl0 3 Neocalanus Sp. 8.3xl0 2 1.6xl0 3 3.8xl0 3 Oithona Sp. 3.3xl0 2 Pseudocalanus Sp.3.3xl0 2 1.lxlO 3 8.3xl0 3 Tortanus Sp. 2.OxlO 2 1.5xl0 2 Appendix 1 17 7 T a b l e :21a Zooplankton D e n s i t i e s North S t n . 6, 1987 Pl a n k t o n Grouping June 19 J u l y 20 August 5 Mean S.D. n=3 Mean S.E. n=3 Number ) Amphipoda 3 . 6 x l 0 2 3.5X10 1 4 . 2 x l 0 2 3.3x10° 6.OxlO 2 Chaetognatha 8.4X10 1 1.9X10 1 6 . 2 X 1 0 1 4.0x10° 8.9X10 1 E u p h a u s i i a 4 . 6 x l 0 2 4.3X10 1 2 . 4 4 x l 0 3 5.7x10° 4 . 4 x l 0 3 Crab Larvae l . l x l O 3 1 . 3 x l 0 2 1 . 2 x l 0 2 1.5X10 1 2 . 3 x l 0 2 Ctenophora 3 . 5 x l 0 2 4.4X10 1 8 . 2 X 1 0 1 4.9x10° l . O x l O 3 Copepoda 8.09 x l 0 3 3 . 0 7 x l 0 2 1.50xl0 3 8.63X10 1 6.13xl0 3 T o t a l 1.05xl0 4 2 . 4 7 x l 0 2 4.62xl0 3 1.15xl0 2 1.24xl0 4 Appendix 1 178 Table :21b Zooplankton D e n s i t i e s North S t n . 6, 1987 Copepoda Major Species Composition June 19 J u l y 20 August 5 ( i n d i v i d u a l s ) A c a r t i a Sp. 2 . 5 x l 0 3 3.4X10 1 7 . 5 x l 0 2 Calanus Sp. 4 . 9 x l 0 2 7 . 5 x l 0 2 Centropages Sp. 9.3X10 1 M e t r i d i a Sp. 2 . 9 x l 0 3 8.7X10 1 3.3X10 1 Neocalanus Sp. 7 . 3 x l 0 2 4 . 3 x l 0 2 3 . 2 x l 0 3 O i t h o n a Sp. 1 . 2 x l 0 3 2 . 6 x l 0 2 Pseudocalanus Sp. 1 . 3 x l 0 3 2 . 9 x l 0 2 1 . 3 x l 0 3 T o r t a n u s Sp. 2 . 4 x l 0 2 6 . 2 X 1 0 1 Appendix 1 17 9 Table:22 Zooplankton D e n s i t i e s North S t n . 7 P l a n k t o n June 19 J u l y 20 August 5 Grouping Number (m ) Amphipoda 2 . 1 x l 0 2 4 . 7 x l 0 2 5 •OxlO 2 Chaetognatha 3 . 2 x l 0 2 E u p h a u s i i a 6 . 5 x l 0 2 3 . 4 x l 0 3 2 . l x l O 3 Crab Larvae 8 . 8 x l 0 2 2.OxlO 2 1 . 9 x l 0 2 Ctenophora 1 . l x l O 2 1 . 7 x l 0 2 1 . 1 7 x l 0 3 Copepoda 3.6 2 x l 0 3 1.lOxlO 4 9 • 9 0 x l 0 3 T o t a l 5 . 7 8 x l 0 3 1.52xl0 4 1 . 3 8 x l 0 4 Copepoda Major S p e c i e s Composition -( i n d i v i d u a l s . m ) A c a r t i a Sp. 1 . 3 x l 0 3 6 . 9 x l 0 2 Calanus Sp. 4 . 8 x l 0 3 4 . 3 x l 0 3 M e t r i d i a Sp. 6 . 2 x l 0 2 3 . 3 x l 0 2 1 . 3 x l 0 3 Neocalanus Sp. 6 . 2 x l 0 2 4 . 6 x l 0 3 3 • 4 x l 0 3 O i t h o n a Sp. 5 . 2 x l 0 2 3 .OxlO 2 Pseudocalanus Sp . 1 . 9 x l 0 3 7 . 7 x l 0 2 Tortanus Sp. 2 . 2 x l 0 2 Appendix 1 180 Table:23 Zooplankton Densities North Stn. 8 Plankton June 19 July 20 August 5 Grouping Number (m2) Amphipoda 7.4xl0 2 3.5xl0 2 1.2xl0 2 Chaetognatha 2.5xl0 2 3.8X101 Euphausiia 4.4xl0 2 8.OxlO 2 6.5xl0 2 Crab Larvae 4.9xl0 2 9.6X101 3.8X101 Ctenophora 3.2xl0 2 1.6xl0 2 l.OxlO 3 Copepoda 4.86xl0 3 3.lOxlO 3 1.95xl0 3 Total 7.10xl0 3 4.50xl0 3 3.82xl0 3 Copepoda Major Species Composition (in d i v i d u a l s ) A c a r t i a Sp. 2.3xl0 3 1.2xl0 2 Calanus Sp. 6.8xl0 2 6.OxlO 2 Metridia Sp. 6.7xl0 2 Neocalanus Sp. 1.9xl0 2 1.lxlO 3 6.4xl0 2 Oithona Sp. l.OxlO 3 Pseudocalanus Sp.6.7xl0 2 9.3xl0 2 4.5xl0 2 Tortanus Sp. 6. l x l O 1 Appendix 1 181 Table:24 Zooplankton Densities North Stn. 9, 1987 Plankton July 20 August 5 Grouping Mean S. E. n=3 Number (m ) Amphipoda 9.4xl0 2 1. 3X10 1 1 .80x10 3 Chaetognatha 2.4xl0 2 5. 9x10° 3 •8X101 Euphausiia 1.06xl0 3 1. 3X10 1 1 .64x10 3 Crab Larvae 7.4X101 5. 7x10° Ctenophora 1.4xl0 2 8. 8x10° 9 .6xl0 2 Copepoda 2.46xl0 3 5. 3X10 1 2 .39x10 4 Total 4.91xl0 3 1. OOxlO2 2 .83x10 4 Copepoda Major Species Composition 9 ( i n d i v i d u a l s . m ) A c a r t i a Sp. 2.6X101 Calanus Sp. 4.3xl0 2 9 .6xl0 2 Centropages Sp. 6.lxlO 1 Metridia Sp. 8.7X101 2 . l x l O 3 Neocalanus Sp. 5.OxlO 2 3 •8xl0 3 Oithona Sp. 1.9X101 Pseudocalanus Sp .8.7xl0 2 1 .3xl0 4 Tortanus Sp. 2.9X101 Appendix 1 182 Table:25 Zooplankton Densities South Stn. 1, 1986 Plankton July 11 September 2 Grouping Number (m2) Amphipoda 2.93xl0 4 5.6xl0 2 Chaetognatha 3.9xl0 3 1.4xl0 2 Euphausiia 2.25xl0 3 2.57xl0 3 Crab Larvae 5.6xl0 2 Ctenophora 5.7xl0 2 Copepoda 2.31xl0 5 3.80xl0 4 Total 2.67xl0 5 4.19xl0 4 Copepoda Major Species Composition (individuals.m M e t r i d i a Sp. 1.8xl0 5 3.4xl0 4 Neocalanus Sp 1.7xl0 4 2.9xl0 3 Oithona Sp. 4.3xl0 3 7.3xl0 2 Pseudocalanus Sp. 3.OxlO4 Appendix 1 183 Table:26 Zooplankton D e n s i t i e s South Stn 2, 1986 P l a n k t o n J u l y 11 September 2 Grouping Number (m 2) Amphipoda 1.08xl0 4 1 . 8 3 x l 0 3 Chaetognatha 5 . 7 x l 0 3 1 . 4 x l 0 2 E u p h a u s i i a 3.25xl0 3 2 . 5 3 x l 0 3 Crab Larvae 8 . 5 x l 0 2 Ctenophora 1.3xl0 3 7.OxlO 2 Copepoda 6.14xl0 4 1.44xl0 4 T o t a l 8.276xl0 4 1.96xl0 4 Copepoda Major S p e c i e s Composition o ( i n d i v i d u a l s . m ) A c a r t i a Sp. 1.5xl0 4 8 . 8 x l 0 2 M e t r i d i a Sp. 2 . 5 x l 0 4 5 . 2 x l 0 3 Neocalanus Sp. 8 . l x l O 3 2.OxlO 3 O i t h o n a Sp. 2.OxlO 3 1 . 7 x l 0 3 Pseudocalanus S. l . l x l O 4 4 . 6 x l 0 3 Appendix 1 184 Table:27 Zooplankton Densities South Stn. 3, 1986 Plankton July 11 September 2 Grouping n Number (m ) Amphipoda 7.46xl0 3 1.55xl0 3 "Chaetognatha l . l x l O 3 1.4x102 Euphausiia 3.39xl0 3 8.18xl0 3 Crab Larvae 1.4x102 Ctenophora 4.2x102 2.8x102 Polychaeta 1.4x102 Copepoda 5.17xl0 4 7.46xl0 3 T o t a l 6.44xl0 4 1.76xl0 4 Copepoda Major Species Composition (individuals.m ) A c a r t i a Sp. 6.7xl0 3 1.5x102 Metridia Sp. 3.9xl0 4 2.7xl0 3 Neocalanus Sp • 1.9xl0 3 1.9xl0 3 Oithona Sp. 9.6x102 6.0x102 Pseudocalanus Sp . 2.9xl0 3 1.9xl0 3 Appendix 1 185 Table:28 Zooplankton Densities South Stn. 4, 1986 Plankton July 11 September 2 Grouping 9 Number (m ) Amphipoda 4.97xl0 3 2.67xl0 3 Chaetognatha 8.6xl0 2 Euphausiia 6.52xl0 3 1.59xl0 3 Crab Larvae 4.92xl0 3 Ctenophora 4.2xl0 2 7.04102 Polychaeta 5.6xl0 2 1.7xl0 2 Copepoda 5.14xl0 4 2.18xl0 4 T o t a l 6.97xl0 4 2.70xl0 4 Copepoda Major Species Composition , , 9 (individuals.m ) A c a r t i a Sp. 1.5xl0 4 Metridia Sp. 2.6xl0 4 1.4xl0 4 Neocalanus Sp • 3.8xl0 3 3.1xl0 3 Oithona Sp. 9.5xl0 2 1.7xl0 3 Pseudocalanus Sp . 5.7xl0 3 1.3xl0 3 Tortanus Sp. 8.7xl0 2 Appendix 1 186 Table:28 Zooplankton D e n s i t i e s South Stn 5, 1986 P l a n k t o n J u l y 11 September 2 Grouping Number (m 2) Amphipoda 1.18xl0 4 1.27xl0 3 Chaetognatha 3 . 9 x l 0 3 2 . 8 x l 0 2 E u p h a u s i i a 7.90xl0 3 2 . 2 x l 0 2 Crab Larvae 5 . 6 x l 0 2 2 . 8 x l 0 2 Ctenophora 1 . l x l O 3 1 . 4 x l 0 2 P o l y c h a e t a 5 . 6 x l 0 2 8 . 5 x l 0 2 Copepoda 7.15xl0 4 2 . 3 8 x l 0 4 T o t a l 9.75xl0 4 2 . 8 8 x l 0 4 Copepoda Major S p e c i e s Composition ( i n d i v i d u a l s . m ) A c a r t i a Sp. 1.5xl0 4 4 . 8 x l 0 2 M e t r i d i a Sp. 3.OxlO 4 1 . 7 x l 0 4 Neocalanus Sp. 8.1x10 J 1 . 4 x l 0 3 O i t h o n a Sp. 4 . 8 x l 0 2 Pseudocalanus Sp. 1.9xl0 4 3 . 8 x l 0 3 Tortanus Sp. 4 . 8 x l 0 2 Appendix 1 187 Table:29 Zooplankton Densities South Stn. 6, 1986 Plankton July 11 September 2 Grouping Number (m2) Amphipoda 1.07xl0 4 2.3xl0 3 Chaetognatha 4.5xl0 3 1.3xl0 3 Euphausiia 1.69xl0 3 1.80xl0 3 Crab Larvae 5.6xl0 2 1.4xl0 2 Ctenophora 4.2xl0 2 Copepoda 7.38xl0 4 2.44xl0 4 T o t a l 9.12xl0 4 3.02xl0 4 Copepoda Major Species Composition (individ u a l s .m ) A c a r t i a Sp. 1.6xl0 4 9 •4xl0 2 M e t r i d i a Sp. 4.4xl0 4 1 .6xl0 4 Neocalanus Sp. 7.4xl0 3 2 .3xl0 3 Oithona Sp. 5.9xl0 3 Pseudocalanus Sp. 5 .2xl0 3 Appendix 1 188 Table:30 Zooplankton Densities South Stn 7, 1986 Plankton July 11 September 2 Grouping Mean S.E. n=3 Mean S. E. n=3 Number (m ) Amphipoda 5.60xl0 3 4.77xl0 2 6.lOxlO 3 6 .71x10 3 Chaetognatha 5.3xl0 2 l.OxlO 1 4.7xl0 2 1 .4xl0 2 Euphausiia 3.58xl0 3 7.72xl0 2 2.53xl0 3 3 .50x10 2 Crab Larvae 9.4X101 3.8X101 8.9xl0 2 3 •3xl0 2 Ctenophora 6.6xl0 2 2.3xl0 2 2.3xl0 2 1 -4xl0 2 Copepoda 3.21xl0 4 5.01xl0 3 7.87xl0 4 1 .81x10 4 Total 4.26xl0 4 6.42xl0 3 8.89xl0 4 2 .06x10 3 Copepoda Major Species Composition (i n d i v i d u a l s • m2) A c a r t i a Sp. 4.3xl0 3 6.6xl0 3 Metridia Sp. 1.9xl0 4 6.lxlO 4 Neocalanus Sp 2.7xl0 3 6.9xl0 3 Oithona Sp. 3.8xl0 2 1.lxlO 3 Pseudocalanus Sp.4.5xl0 3 2.3xl0 3 Tortanus Sp. 3.8xl0 2 3.4xl0 2 Appendix 1 189 Table:31 Zooplankton Densities South Stn. 8, 1986 Plankton July 11 September 2 Grouping Number (m2) Amphipoda 1.41xl0 3 2.25xl0 3 Chaetognatha 1.8xl0 3 Euphausiia 4.3xl0 2 4.37xl0 3 Crab Larvae 7.OxlO 2 Ctenophora 1.6xl0 3 9.9xl0 2 Copepoda 1.25xl0 4 4.82xl0 4 Total 1.85xl0 4 5.58xl0 4 Copepoda Major Species Composition (i n d i v i d u a l s . m2) A c a r t i a Sp. 4.2xl0 3 4.6xl0 3 Metridia Sp. 1.6xl0 3 1.9xl0 4 Neocalanus Sp. 1.6xl0 3 8.3xl0 3 Oithona Sp. 7.4xl0 3 Pseudocalanus Sp. 5.2xl0 3 9.3xl0 3 Appendix 1 190 Table:32 Zooplankton Densities South Stn. 9, 1986 Plankton July 11 September 2 Grouping Number (m ) Amphipoda 3.37xl0 3 2.11xl0 3 Chaetognatha 3.2xl0 3 7.OxlO 2 Euphausiia 9.9xl0 2 1.31xl0 3 Crab Larvae 5.6xl0 2 2.8xl0 2 Ctenophora 5.6xl0 2 2.8xl0 2 Copepoda 1.58xl0 4 4.13xl0 4 T o t a l 2.45xl0 4 4.59xl0 4 Copepoda Major Species Composition • • 9 (individuals.m) A c a r t i a Sp. 1.9xl0 3 7 •6xl0 2 M e t r i d i a Sp. 8.2xl0 3 2 •8xl0 4 Neocalanus Sp. 1.6xl0 3 1 . l x l O 4 Oithona Sp. 6.3xl0 2 Pseudocalanus Sp. 3.5xl0 3 2 .3xl0 3 Appendix 1 191 Table:33 Zooplankton Densities South Stn. 10, 1986 Plankton July 11 September 2 Grouping Mean S. E. n=3 Number (m2) Amphipoda 4.36xl0 3 4. 65xl0 2 6.76xl0 3 "Chaet ognat ha 1.3xl0 3 4. 4x l 0 2 1.7xl0 3 Euphausiia 7.6xl0 2 3. 9X10 1 2.81xl0 3 Crab Larvae 4.7X101 3. 8X10 1 5.6xl0 2 Ctenophora 2.8xl0 2 1. 2xl0 2 5.6xl0 2 Copepoda 3.33xl0 4 1. 75xl0 3 4 .56xl0 4 Total 4.OOxlO4 2. 61xl0 3 5.80xl0 4 Copepoda Major Species Composition ( i n d i v i d u a l s . m ) A c a r t i a Sp. 4.3xl0 3 Metridia Sp. 2.OxlO 4 3 .9xl0 4 Neocalanus Sp. 1.8xl0 3 5 ,5xl0 3 Oithona Sp. 4.2xl0 2 Pseudocalanus sp. 5.6xl0 3 9 . l x l O 2 Tortanus Sp. 5.6xl0 2 Appendix 1 192 Table: 3 4 Zooplankton Densities South Stn 11, 1986 Plankton July 11 September 2 Grouping Number (m ) Amphipoda 1.83xl0 3 9.01xl0 3 Chaetognatha 7.OxlO 2 l . l x l O 3 Euphausiia 1.5xl0 2 4.6xl0 3 Crab Larvae 1.4xl0 2 Ctenophora 2.8xl0 2 1.7xl0 3 Polychaeta 1.4xl0 2 Copepoda 2.96xl0 4 1.73xl0 4 T o t a l 3.28xl0 4 1.89xl0 5 Copepoda Major Species Composition 9 (individuals.m ) A c a r t i a Sp. 4.5xl0 3 Metridia Sp. 1.7xl0 4 1.6xl0 5 Neocalanus Sp. 2.2xl0 3 9.4xl0 3 Oithona Sp. 3.1xl0 3 Pseudocalanus Sp 4.5xl0 3 3 . l x l O 3 Appendix 1 193 Table:35 Zooplankton Densities South Stn. 12, 1986 Plankton July 11 September 2 Grouping Number (m*) Amphipoda 3.8xl0 3 4.5xl0 3 Chaetognatha 7.OxlO2- 1.lxlO 3 Euphausiia l . l x l O 3 1.7xl0 3 Crab Larvae 2.8xl0 2 5.6xl0 2 Ctenophora 1.4xl0 2 5.6xl0 2 Polychaeta 2.8xl0 2 Copepoda 2.80xl0 4 9.69xl0 4 Total 3.44xl0 4 1.05xl0 5 Copepoda Major Species Composition (individuals.m ) A c a r t i a Sp. 4.6xl0 3 1. 8xl 0 3 Metridia Sp. 1.8xl0 4 8. 6xl0 4 Neocalanus Sp. 9.2xl0 2 3. 6x l 0 3 Oithona Sp. 4.6xl0 2 1. 8x l 0 3 Pseudocalanus Sp. 4.3xl0 3 1. 8xl 0 3 Appendix 1 194 Table:36 Zooplankton Densities South Stn. 13, 1986 Plankton July 11 September 2 Grouping o Number (m ) Amphipoda 5.91xl0 3 2.96xl0 3 Chaetognatha 9.96xl0 2 4.2xl0 2 Euphausiia 1.69xl0 3 5.8xl0 2 Crab Larvae 1.4xl0 2 1.4xl0 2 Ctenophora 5.6xl0 2 2.8xl0 2 Polychaeta 1.4xl0 2 5.6xl0 2 Copepoda 4.26xl0 4 2.37xl0 4 T o t a l 5.21xl0 4 2.86xl0 4 Copepoda Major Species Composition (individuals.m ) A c a r t i a Sp. 4.4xl0 3 M e t r i d i a Sp. 2.4xl0 4 1.6xl0 4 Neocalanus Sp. 5.1xl0 3 4.5xl0 3 Oithona Sp. 3.7xl0 3 8.9xl0 2 Pseudocalanus Sp. 5.1xl0 3 1.8xl0 3 Tortanus Sp. 7.4xl0 2 Appendix 1 195 Table:37 Zooplankton D e n s i t i e s South Stn. 14, 1986 P l a n k t o n J u l y 11 September 2 Grouping o Number (m ) Amphipoda 2 . 8 2 x l 0 3 1 . 3 x l 0 3 Chaetognatha 9 . 9 x l 0 2 4 . 2 x l 0 2 E u p h a u s i i a 2 . 5 4 x l 0 3 1 . 3 x l 0 3 Crab Larvae 1 . 4 x l 0 2 1.8X10 1 Ctenophora 1 . 4 x l 0 2 9 . 9 x l 0 2 P o l y c h a e t a 5 . 6 x l 0 2 Copepoda 2.9 4 x l 0 4 5.56xl0 4 T o t a l 3 . 6 0xl0 4 6.02xl0 4 Copepoda Major S p e c i e s Composition ( i n d i v i d u a l s .m ) A c a r t i a Sp. 4 . 4 x l 0 3 M e t r i d i a Sp. 1 . 8 x l 0 4 3. 7 x l 0 4 Neocalanus Sp. l . l x l O 3 9. l x l O 3 Oithona Sp. 2 . 2 x l 0 3 4. OxlO 3 Pseudocalanus Sp. 2 . 8 x l 0 3 5. l x l O 3 Appendix 1 196 T a b l e : 3 8 Zooplankton Densities South Stn. 15, 1986 Plankton July 11 September 2 Grouping Mean S.E. n=3 Mean S . E. n= 3 Number (m2) Amphipoda 5.91xl0 3 7.97xl0 2 3.94xl0 3 3 .05x10 2 Chaetognatha 1.2xl0 3 2.9xl0 2 2.3xl0 2 7 .7X101 Crab Larvae 4.7X101 1.4xl0 2 1 .2x10° Ctenophora 4.7xl0 2 1.3xl0 2 4.7X101 3 .8X10 1 Polychaeta 9.4X10 1 Copepoda 2.84xl0 4 5.09xl0 3 3.21xl0 4 3 .90x10 3 Tota l 3.70xl0 4 5.93xl0 3 3.85xl0 4 4 .24x10 3 Copepoda Major Species Composition (in d i v i d u a l 9 s .m^  ) A c a r t i a Sp. 4.3xl0 3 1.6xl0 2 Metridia Sp. 1.7xl0 4 2.4xl0 4 Neocalanus Sp. 4.2xl0 3 2.6xl0 3 Oithona Sp. 2.1xl0 2 l.OxlO 3 Pseudocalanus Sp. 2.5xl0 3 4.OxlO 3 Appendix 1 197 Table:3 9 Zooplankton Densities South Stn. 16, 1986 Plankton July 11 September 2 Grouping o Number (m ) Amphipoda 2.68xl0 3 5.8xl0 3 Chaetognatha 4.2xl0 2 2.8xl0 2 Euphausiia 9.67xl0 2 l.OxlO 3 Ctenophora 3.2xl0 2 Copepoda 6.62xl0 3 3.79xl0 4 T o t a l l . l O x l O 4 4.50xl0 4 Copepoda Major Species Composition (individuals.m ) A c a r t i a Sp. 2.2xl0 3 Metridia Sp. 1.3xl0 3 1 .9xl0 4 Neocalanus Sp. 5 .5xl0 3 Oithona Sp. 9.6xl0 2 5 .5xl0 3 Pseudocalanus Sp. 2.2xl0 3 8 .3xl0 3 Appendix 1 198 Table:40 Zooplankton Densities South Stn. 17, 1986 Plankton July 11 September 2 Grouping Number (m ) Amphipoda 7.46xl0 3 3.10xl0 3 Chaetognatha 3.2xl0 3 Euphausiia 5.6xl0 2 1.24xl0 3 Crab Larvae 1.4xl0 2 Ctenophora 4.2xl0 2 4.2xl0 2 Copepoda 1.lOxlO 4 2.75xl0 4 Total 2.27xl0 4 3.22xl0 4 Copepoda Major Species Composition (individuals.m ) A c a r t i a Sp. 2.9xl0 3 Metridia Sp. 3.3xl0 3 2 .OxlO 4 Neocalanus Sp. 2.2xl0 3 3 .3xl0 3 Oithona Sp. 1.3xl0 3 1 .lOxlO 3 Pseudocalanus Sp. 2.4xl0 3 2 .7xl0 3 Tortanus Sp. 5 •5xl0 2 Appendix 1 199 Table:41 Zooplankton D e n s i t i e s South Stn. 18, 1986 P l a n k t o n J u l y 11 September 2 Grouping Mean S .E. n=3 Number (m ) Amphipoda 3.00xl0 3 3 . 9 2 x l 0 2 2.OxlO 3 Chaetognatha 1.6xl0 3 1 . 2 x l 0 2 8 . 5 x l 0 2 E u p h a u s i i a 6.65xl0 2 1 . 2 0 x l 0 2 5 . 2 x l 0 2 Crab Larvae 1.4xl0 2 1 . 5 x l 0 2 Ctenophora 4 . 2 x l 0 2 5 .8X10 1 8 . 5 x l 0 2 P o l y c h a e t a 4.7X10 1 Copepoda 3.00xl0 4 1 . 5 0 x l 0 3 3 . 8 3 x l 0 4 T o t a l 3.60xl0 4 1 . 8 8 x l 0 3 4 . 2 6 x l 0 4 Copepoda Major S p e c i e s Composition ( i n d i v i d u a l s . m ) A c a r t i a Sp. 3.OxlO 3 M e t r i d i a Sp. 1.9xl0 4 3 .OxlO 4 Neocalanus Sp. 3 . 9 x l 0 3 4 . 5 x l 0 3 O i t h o n a Sp. 4 . 8 x l 0 2 Pseudocalanus Sp. 3 . 2 x l 0 3 3 •OxlO 3 Appendix 1 200 T a b l e : 4 2 Zooplankton D e n s i t i e s South Stn. 19, 1986 P l a n k t o n J u l y 11 September 2 Grouping 2 Number (m ) Amphipoda 6 . 3 x l 0 3 1 . 7 x l 0 3 Chaetognatha 1 . 3 x l 0 3 8 . 5 x l 0 2 E u p h a u s i i a 1 . 3 x l 0 3 2.OxlO 3 Crab Larvae 1 . 4 x l 0 2 1 . 4 x l 0 2 Ctenophora 2 . 8 x l 0 2 7.OxlO 2 P o l y c h a e t a 2 . 8 x l 0 2 2 . 8 x l 0 2 Copepoda 4.07xl0 4 3 . 9 4 x l 0 4 T o t a l 5 . 0 3xl0 4 4 . 4 8 x l 0 4 Copepoda Major S p e c i e s Composition ( i n d i v i d u a l s . m ) A c a r t i a Sp. 7 . 4 x l 0 3 7 . 9 x l 0 2 M e t r i d i a Sp. 2 . 3 x l 0 4 3 . 2 x l 0 4 Neocalanus Sp. 1 . 2 x l 0 3 3 . 2 x l 0 3 O i t h o n a Sp. 1 . 2 x l 0 3 Pseudocalanus Sp. 6 . 8 x l 0 3 3 . 9 x l 0 3 Appendix 1 201 Table:4 3 Zooplankton D e n s i t i e s South S t n . 20, 1986 P l a n k t o n J u l y 11 September 2 Grouping Number (m ) Amphipoda 4.78xl0 3 3 . l O x l O 3 Chaetognatha 1 . 8 x l 0 3 2 . 8 x l 0 2 E u p h a u s i i a 2 . 8 x l 0 2 6 . 2 x l 0 2 Ctenophora 5 . 6 x l 0 2 7 . 1 x l 0 2 Copepoda 2.2 8 x l 0 4 2 . 8 4 x l 0 4 T o t a l 3 .03xl0 4 3 . 3 2 x l 0 4 Copepoda Major S p e c i e s Composition o ( i n d i v i d u a l s . m ) A c a r t i a Sp. 7 . 5 x l 0 3 5 . 4 x l 0 2 M e t r i d i a Sp. 8 . 3 x l 0 3 1 . 9 x l 0 4 Neocalanus Sp. 1 . 2 x l 0 3 5 . 9 x l 0 3 Oithona Sp. 4 . 2 x l 0 2 5 . 4 x l 0 2 Pseudocalanus Sp 4 . 6 x l 0 3 2 . 7 x l 0 3 Appendix 1 202 Table: 44 Zooplankton Densities North Stn. 1, 1986 Plankton July 13 Grouping Mean S .E. n=3 Number (m ) Amphipoda 6.45X10 1 1 .73X10 1 Chaetognatha 5.57X10 1 2 .50x10 1 Euphausiia 9.09X10 1 4 .16X10 1 Crab Larvae 1.26xl0 3 1 .53xl0 2 Ctenophora 6.37xl0 2 8 .56X10 1 Copepoda 2.306xl0 3 3 .166xl0 2 T o t a l 4.371xl0 3 5 .668xl0 2 Copepoda Major Species Composition (individuals.m) A c a r t i a Sp. l . l x l O 3 Metridia Sp. 2.1xl0 2 Neocalanus Sp. 4.5xl0 2 Oithona Sp. 3.5X10 1 Pseudocalanus Sp. 6.lxlO 2 Tortanus Sp. 1.7X10 1 Appendix 1 2 03 T a b l e : 45 Zooplankton D e n s i t i e s North Stn. 2, 1986 P l a n k t o n J u l y 13 September 2 Grouping Number (m ) Amphipoda 1.20xl0 3 1 . l x l O 3 Chaetognatha 2 . 1 x l 0 2 1 . 4 x l 0 2 E u p h a u s i i a 3.5X101 4 . 0 8 x l 0 3 Crab Larvae 2 . 6 1 x l 0 3 4 . 2 x l 0 2 Ctenophora 2 . 3 9 x l 0 3 l . l x l O 3 Copepoda 6.30xl0 3 1.13xl0 4 T o t a l 1.27xl0 4 1.82xl0 4 Copepoda Major S p e c i e s Composition ( i n d i v i d u a l s . m ) A c a r t i a Sp. 1 . 8 x l 0 3 M e t r i d i a Sp. 7 . 6 x l 0 2 4 . 9 x l 0 3 Neocalanus Sp • 1 . 3 x l 0 3 3 . 8 x l 0 3 O i t h o n a Sp. 2 . 2 x l 0 2 Pseudocalanus Sp. 2 . 5 x l 0 3 2 . 2 x l 0 3 Appendix 1 204 Table: 46 Zooplankton Densities North Stn. 3, 1986 Plankton July 13 September 2 Grouping Number (m ) Amphipoda 1.4xl0 2 1.4xl0 3 Chaetognatha 2.5xl0 2 1.4xl0 2 Euphausiia 2.3xl0 3 Crab Larvae 1.lxlO 2 4.2xl0 2 Ctenophora 3.5X101 4.2xl0 2 Copepoda 5.00xl0 3 1.93xl0 4 Total 5.53xl0 3 2.39xl0 4 Copepoda Major Species Composition ( i n d i v i d u a l s , m ) A c a r t i a Sp. 3.9xl0 2 Metridia Sp. 2.9xl0 3 8.3xl0 3 Neocalanus Sp • 5.5xl0 2 9.5xl0 3 Oithona Sp. 7.8X101 Pseudocalanus Sp. l . l x l O 3 1.9xl0 3 Appendix 1 205 Table: 4 7 Zooplankton Densities North Stn. 4, 1986 Plankton July 13 Grouping Number (m ) Amphipoda 1.4xl0 3 Chaetognatha 1.5xl0 3 Euphausiia l.OxlO 2 Crab Larvae 1.4xl0 2 Ctenophora 7 .OxlO 2 Copepoda 3.52xl0 4 T o t a l 4.00xl0 4 Copepoda Major Species Composition ( i n d i v i d u a l s .m ) Met r i d i a Sp. 3.3xl0 4 Neocalanus Sp. 6.5xl0 2 Pseudocalanus Sp. 1.3xl0 3 Tortanus Sp. 6.5xl0 2 Appendix 1 206 Table: 48 Zooplankton Densities North Stn 5, 1986 Plankton July 13 September 2 Grouping Number (m ) Amphipoda 2.7xl0 3 3.2xl0 3 Chaetognatha 7.OxlO 2 2.8xl0 2 Euphausiia 3.2X10 1 8.3xl0 3 Crab Larvae 1.4xl0 2 Ctenophora 7.OxlO 2 1.4xl0 2 Polychaeta 1.4xl0 2 Copepoda 3.73xl0 4 2.84xl0 4 T o t a l 4.17xl0 4 4.04xl0 4 Copepoda Major Species Composition 9 ( i n d i v i d u a l s . m ) A c a r t i a Sp. 2.2xl0 3 M e t r i d i a Sp. 2.9xl0 4 1.3xl0 4 Neocalanus Sp. 2.2xl0 3 1.5xl0 4 Pseudocalanus Sp. 2.9xl0 3 l.OxlO 3 Appendix 1 207 T a b l e : 4 9 Zooplankton D e n s i t i e s North S t n . 6, 1986 P l a n k t o n J u l y 13 September 2 Grouping Mean S.E. n=3 Number (m 2) Amphipoda 1 . 9 x l 0 3 2 . 1 x l 0 2 1 . 6 x l 0 3 Chaetognatha 4 . 7 x l 0 2 E u p h a u s i i a 2 . 8 x l 0 2 6.5X10 1 5 . 6 x l 0 3 Crab Larvae 4.7X10 1 1 . 4 x l 0 2 Ctenophora 9 . 4 x l 0 2 2.OxlO 2 9 . 9 x l 0 2 P o l y c h a e t a 4.7X10 1 Copepoda 1.93xl0 4 1.43xl0 3 1.96xl0 4 T o t a l 2 . 3 0 x l 0 4 1.50xl0 3 2 . 7 9 x l 0 4 Copepoda Major S p e c i e s Composition ( i n d i v i d u a l s . m ) A c a r t i a Sp. 7 . 9 x l 0 2 M e t r i d i a Sp. 1. 3 x l 0 4 l . l x l O 4 Neocalanus Sp • 2 . 8 x l 0 3 7 . 3 x l 0 3 Oithona Sp. 2 . 2 x l 0 2 Pseudocalanus Sp. 2 . 1 x l 0 3 l . l x l O 3 Appendix 1 2 08 T a b l e : 50 Zooplankton D e n s i t i e s North Stn. 7, 1986 P l a n k t o n J u l y 13 September 2 Grouping Number (m ) Amphipoda 2.OxlO 3 1 . 3 x l 0 3 E u p h a u s i i a 3.OxlO 2 3 . 9 x l 0 3 Crab Larvae 7.OxlO 2 8 . 5 x l 0 2 Ctenophora 7.OxlO 2 1 . 4 x l 0 3 P o l y c h a e t a 1.4xl0 2 2 . 8 x l 0 2 Copepoda 1.53xl0 4 2 . 6 2 x l 0 4 T o t a l 1.92xl0 4 3 . 3 9 x l 0 4 Copepoda Major S p e c i e s Composition ( i n d i v i d u a l s . m ) A c a r t i a Sp. 5 . 6 x l 0 2 9 . 7 x l 0 3 M e t r i d i a Sp. 1 . l x l O 4 1 . 4 x l 0 4 Neocalanus Sp. 2.OxlO 3 9 . 2 x l 0 3 O i t h o n a Sp. 5 . 6 x l 0 2 4 . 9 x l 0 2 Pseudocalanus Sp. 1.7xl0 3 1 . 5 x l 0 3 Appendix 1 209 Table: 51 Zooplankton Densities North Stn. 8, 1986 Plankton July 13 September 2 Grouping o Number (m ) Amphipoda 8.4xl0 2 2.OxlO 3 Euphausiia 1.5xl0 2 7.7xl0 3 Crab Larvae 4.2xl0 2 1.4xl0 2 Ctenophora 2.7xl0 3 8.5xl0 2 Copepoda 8.45xl0 3 1.45xl0 4 T o t a l 1.25xl0 4 2.52xl0 4 Copepoda Major Species Composition (ind i v i d u a l s . m ) A c a r t i a Sp. 8.5xl0 2 2 •9xl0 2 M e t r i d i a Sp. 3.9xl0 3 2 .OxlO 3 Neocalanus Sp • 2.2xl0 3 7 •3xl0 3 Oithona Sp. 1.7xl0 2 Pseudocalanus Sp. 1.4xl0 3 4 .4xl0 3 Appendix 1 210 Table:52 Zooplankton Densities North Stn. 9, 1986 Plankton July 13 September 2 Grouping Number (m ) Amphipoda 8.8xl0 2 8.5xl0 2 Chaetognatha 7.OxlO 2 Euphausiia 9.2xl0 2 6.OxlO2 Crab Larvae 1.8xl0 2 3.5X10 1 Ctenophora 3.2xl0 2 1.lxlO 2 Copepoda 9.22xl0 3 1.92xl0 4 Total 1.15xl0 4 2.08xl0 4 Copepoda Major Species Composition (individuals.m ) A c a r t i a Sp. 3.l x l O 2 Metridia Sp. 7.3xl0 3 1.6xl0 4 Neocalanus Sp • 4.7xl0 2 l.OxlO 3 Oithona Sp. 1.6xl0 2 Pseudocalanus Sp. 2.4xl0 3 Appendix 1 211 Table: 53 Zooplankton Densities North Stn. 11, 1986 Plankton July 13 Grouping 2 Number (m ) Amphipoda 1.4xl0 3 Euphausiia 3.9xl0 2 Crab Larvae 3.9xl0 2 Ctenophora 2.1xl0 2 Polychaeta 3.5X10 1 Copepoda 8.20xl0 3 Total 1.02xl0 4 Copepoda Major Species Composition (individuals.m) A c a r t i a Sp. 7.7xl0 2 M e t r i d i a Sp. 4.8xl0 3 Neocalanus Sp. 1.5xl0 3 Oithona Sp. 1.6xl0 2 Pseudocalanus Sp. 9.3xl0 2 Appendix 1 212 T a b l e : 54 Zooplankton D e n s i t i e s North Stn. 12, 1986 P l a n k t o n J u l y 13 Grouping Mean S.E. n=3 Number (m ) Amphipoda 1. 2 x l 0 3 4.4X10 1 Chaetognatha 2 . 8 x l 0 2 E u p h a u s i i a 2 . 3 x l 0 2 8.3X10 1 Crab Larvae 1.5xl0 3 3 . 6 x l 0 2 Ctenophora 1 . 3 x l 0 3 4 . 2 x l 0 2 Copepoda 1.05xl0 4 8 . 4 1 x l 0 2 T o t a l 1.50xl0 4 1.60xl0 3 Copepoda Major S p e c i e s Composition 9 ( i n d i v i d u a l s . m ) A c a r t i a Sp. 2 . 4 x l 0 2 M e t r i d i a Sp. 1. 8 x l 0 3 Neocalanus Sp. 4 . 1 x l 0 3 O i t h o n a Sp. 5.4X10 1 Pseudocalanus Sp. 4 . 2 x l 0 3 T o r t a n u s Sp. 6.6X10 1 213 Appendix 2 Horizontal d i s t r i b u t i o n s of the groups Amphipoda, Euphausiia, and Copepoda around Hornby Island during the sampling periods i n 1986 and 1987. Samples were obtained by v e r t i c a l SCOR net (405^ /m mesh) hauls to a depth of 65 m with a r e t r i e v a l rate of ~1 m.s - 1. A p p e n d i x 2 214 (1) D i s t r i b u t i o n of the Group Amphipoda around the southern end of Hornby I s l a n d , Lambert Channel on June 19, 1987. Values g i v e n are i n d i v i d u a l s . m . Dots denote p o s i t i o n of s t a t i o n where sampling took p l a c e ( F i g u r e s 5.1-5.4). Appendix 2 215 (2) D i s t r i b u t i o n of the Group Amphipoda around the souther end of Hornby Island, Lambert Channel on July 17, 1987. Values given are i n d i v i d u a l s . m . Dots denote p o s i t i o n of s t a t i o n where sampling took place (Figures 5.1-5.4). Appendix 2 216 (3) D i s t r i b u t i o n of the Group Amphipoda around the s o u t h e r n end of Hornby I s l a n d , Lambert Channel on August 4, 1987. V a l u e s g i v e n are i n d i v i d u a l s . m . Dots denote p o s i t i o n of s t a t i o n where sampling took p l a c e ( F i g u r e s 5.1-5.4). Appendix 2 217 (4) D i s t r i b u t i o n of the Group Amphipoda around the northern end of Hornby I s l a n d , Lambert Channel on June 19, 1987. Values g i v e n are i n d i v i d u a l s . m . Dots denote p o s i t i o n of s t a t i o n where sampling took place (Figures 5.1-5.4). Appendix 2 218 (5) D i s t r i b u t i o n of the Group Amphipoda around the n o r t h e r n end of Hornby I s l a n d , Lambert Channel on J u l y 20, 1987. V a l u e s g i v e n are i n d i v i d u a l s . m . Dots denote p o s i t i o n of s t a t i o n where sampling took p l a c e ( F i g u r e s 5.1-5.4). A p p e n d i x 2 219 (6) D i s t r i b u t i o n o f t h e G r o u p A m p h i p o d a a r o u n d t h e n o r t h e r n e n d o f H o r n b y I s l a n d , L a m b e r t C h a n n e l on A u g u s t 5, 1 9 8 7 . V a l u e s g i v e n a r e i n d i v i d u a l s . m 2 . D o t s d e n o t e p o s i t i o n o f s t a t i o n w h e r e s a m p l i n g t o o k p l a c e ( F i g u r e s 5 . 1 - 5 . 4 ) . Appendix 2 220 (7) D i s t r i b u t i o n of the Group Amphipoda around the southern end of Hornby Island, Lambert Channel on July 11, 1986. Values given are individuals.m 2. Dots denote p o s i t i o n of s t a t i o n where sampling took place (Figures 5.1-5.4). A p p e n d i x 2 221 (8) D i s t r i b u t i o n o f t h e G r o u p A m p h i p o d a a r o u n d t h e s o u t h e r n e n d o f H o r n b y I s l a n d , L a m b e r t C h a n n e l o n S e p t e m b e r 2 , 1 9 8 7 . V a l u e s g i v e n a r e i n d i v i d u a l s . m . D o t s d e n o t e p o s i t i o n o f s t a t i o n w h e r e s a m p l i n g t o o k p l a c e ( F i g u r e s 5 . 1 - 5 . 4 ) . Appendix 2 222 (9) D i s t r i b u t i o n of the Group Amphipoda around the northern end of Hornby Island, Lambert Channel on July 13, 1986. Values given are i n d i v i d u a l s . i r r. Dots denote p o s i t i o n of s t a t i o n where sampling took place (Figures 5.1-5.4). Appendix 2 223 (10) D i s t r i b u t i o n of the Group Amphipoda around the northern end of Hornby Island, Lambert Channel on September 2, 1986. Values given are i n d i v i d u a l s . m . Dots denote p o s i t i o n of s t a t i o n where sampling took place (Figures 5.1-5.4). • l.lxlO3 DENMAN ISLAND , Phlpps L A M B E R T V p t C H A N N E L BAYNES SOUND WhaltbonV P» 4-124 43- W SCALE 1 : 80.000 124 40-W Appendix 2 224 (11) D i s t r i b u t i o n of the Group Euphausiia around the southern end of Hornby Island, Lambert Channel on June 19, 1987. Values given are individuals.m . Dots denote p o s i t i o n of s t a t i o n where sampling took place (Figures 5.1-5.4). A p p e n d i x 2 225 (12) D i s t r i b u t i o n of the Group Euphausiia around the southern end of Hornby Island, Lambert Channel on July 17, 1987. Values given are i n d i v i d u a l s . m . Dots denote p o s i t i o n of s t a t i o n where sampling took place (Figures 5.1-5.4). Appendix 2 226 (13) D i s t r i b u t i o n of the Group Euphausiia around the southern end of Hornby Island, Lambert Channel on August 4, 1987. Values given are individuals.m 2. Dots denote p o s i t i o n of s t a t i o n where sampling took place (Figures 5.1-5.4). Appendix 2 227 (14) D i s t r i b u t i o n of the Group Euphausiia around the northern end of Hornby Island, Lambert Channel on June 19, 1987. Values given are i n d i v i d u a l s . m . Dots denote p o s i t i o n of s t a t i o n where sampling took place (Figures 5.1-5.4). Appendix 2 228 (15) D i s t r i b u t i o n of the Group Euphausiia around the northern end of Hornby Island, Lambert Channel on July 20, 1987. Values given are i n d i v i d u a l s . m . Dots denote p o s i t i o n of s t a t i o n where sampling took place (Figures 5.1-5.4). A p p e n d i x 2 229 (16) D i s t r i b u t i o n of the Group Euphausiia around the northern end of Hornby Island, Lambert Channel on August 5, 1987. Values given are individuals.m . Dots denote p o s i t i o n of s t a t i o n where sampling took place (Figures 5.1-5.4). Appendix 2 230 (17) D i s t r i b u t i o n of the Group Euphausiia around the southern end of Hornby Island, Lambert Channel on July 11, 1986. Values given are i n d i v i d u a l s . m . Dots denote p o s i t i o n of s t a t i o n where sampling took place (Figures 5.1-5.4). Appendix 2 231 (18) D i s t r i b u t i o n of the Group Euphausiia around the southern end of Hornby Island, Lambert Channel on September 2, 1987. Values given are individuals.m 2. Dots denote p o s i t i o n of s t a t i o n where sampling took place (Figures 5.1-5.4) . . o 5 b eg O) <n Appendix 2 2 32 (19) D i s t r i b u t i o n of the Group Euphausiia around the northern end of Hornby Island, Lambert Channel on July 13, 1986. Values given are i n d i v i d u a l s . m . Dots denote p o s i t i o n of s t a t i o n where sampling took place (Figures 5.1-5 .4). Appendix 2 233 (20) D i s t r i b u t i o n of the Group Euphausiia around the northern end of Hornby Island, Lambert Channel on September 2, 1986. Values given are individuals.rrr. Dots denote p o s i t i o n of st a t i o n where sampling took place (Figures 5.1-5.4 ) . Appendix 2 234 (21) D i s t r i b u t i o n of the Group Copepoda around the southern end of Hornby Island, Lambert Channel on June 19, 1987. Values given are i n d i v i d u a l s . m . Dots denote p o s i t i o n of s t a t i o n where sampling took place (Figures 5.1-5.4). Appendix 2 235 (22) D i s t r i b u t i o n of the Group Copepoda around the southern end of Hornby Island, Lambert Channel on July 17, 1987. Values given are individuals.m . Dots denote p o s i t i o n of s t a t i o n where sampling took place (Figures 5.1-5*4). Appendix 2 236 (23) D i s t r i b u t i o n of the Group Copepoda around the southern end of Hornby Island, Lambert Channel on August 4 1987 Values given are individuals.m 2. Dots denote p o s i t i o n of st a t i o n where sampling took place (Figures 5.1-5.4). Appendix 2 237 (24) D i s t r i b u t i o n of the Group Copepoda around the northern end of Hornby Island, Lambert Channel on June 19, 1987. Values given are i n d i v i d u a l s . m . Dots denote p o s i t i o n of s t a t i o n where sampling took place (Figures 5.1-5.4). Appendix 2 238 (25) D i s t r i b u t i o n of the Group Copepoda around the northern end of Hornby Island, Lambert Channel on July 20, 1987. Values given are i n d i v i d u a l s . m . Dots denote p o s i t i o n of s t a t i o n where sampling took place (Figures 5.1-5.4). Appendix 2 2 39 (26) D i s t r i b u t i o n of the Group Copepoda around the northern end of Hornby Island, Lambert Channel on August 5, 1987. Values given are individuals.m . Dots denote p o s i t i o n of s t a t i o n where sampling took place (Figures 5.1-5.4). Appendix 2 240 (27) D i s t r i b u t i o n of the Group Copepoda around the southern end of Hornby Island, Lambert Channel on July 11, 1986. Values given are i n d i v i d u a l s . m . Dots denote p o s i t i o n of s t a t i o n where sampling took place (Figures 5.1-5.4). Appendix 2 241 (28) D i s t r i b u t i o n of the Group Copepoda around the southern end of Hornby I s l a n d , Lambert Channel on September 2, 1987. Values given are i n d i v i d u a l s . m . Dots denote p o s i t i o n of s t a t i o n where sampling took place (Figures 5.1-5.4). Appendix 2 242 (29) D i s t r i b u t i o n of the Group Copepoda around the northern end of Hornby Island, Lambert Channel on July 13, 1986. Values given are i n d i v i d u a l s . m . Dots denote p o s i t i o n of s t a t i o n where sampling took place (Figures 5.1-5.4). Appendix 2 243 (30) D i s t r i b u t i o n of the Group Copepoda around the northern end of Hornby Island, Lambert Channel on September 2, 1986. Values given are i n d i v i d u a l s . m . Dots denote p o s i t i o n of s t a t i o n where sampling took place (Figures 5.1-5.4). 

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