Some Factors Ihfhjehoino the Distriputioi of Pelagic Copepods

SOME FACTORS IHFHJEHOINO THE DISTRIPUTIOI OF PELAGIC COPEPODS

IH THE qJEEI CHARLOTTE ISLANDS AREA

Prances Blla Cameron

A Thesis Submitted in Partial Fulfillment of

the Requirements for the Degree of

. Master of Arts

In the Department

Zoology

We accept this thesis as conforming to th© standard required

from candidates for the degree of Master of Arts

Members of the Department of Zoology

THE UNIVERSITY 0P BRITISH COLUMBIA

April 1955 -.1

Abstract

The distribution of certain copepod species of the north coast of British Columbia suggests that breeding is restricted to limited regions of well~defined temperature and salinity characteristics, Currents ar® responsible for the spread of juveniles and adults from these areaa* A description of the probable circulation pattern in the vicinity of the Queen Charlotte Islands as Inferred from plankton collections 1® submitted* TABLE OF CONTENTS

PAGE INTRQDUCTION «#•«•*»«•••»•»#»•••#»»•»•••»*«*»«*»»•»»*» X

METHODS AID MATERIALS «#*,..»•...•»*«.•••«•» ,. #. 4

Vertical Distribution ••*•••*•»*•••••••••«•<.•••••••« 5

Horizontal Distribution »**••.•#**«*•»•»•*»«*••••.»* 8

RESULTS •»...,»•..=»»««*«•«»»»»•••»«•«••*»••»«••*•••<• 11

DISCUSSXON •••»•••••#«••»••••••«••»••••«*«••»••••«»•«» 18

The distribution®/Of the more common species 18

Currents suggested Py the dispersal of eopepeds .**« 3®

Tasu Inlet »•••«»»»••*#»•»•••«»«»••»••«•»»•»•«•«»• 39

Dixon Entranoe ««»»##**«**»#»**%•«*»*«**•**»##**«* 45

Masset Inlet •»•««••»•»••».•«•»•*»••••••«••••••«•• 49

SUMMARY AND 0OK0KJSI0HS »»«••...•,*•..,•.»•*.,»,,,.••* 57

ACI10WL1DG1EITS ....ft.,.,*...... *...*,...... 59

BIBLIOGRAPHY1 «*••«•»»«»«»»**•*•»«•••. *»•»•*»,•*«**••**** 60 APPE'MDIl • LlSf 0? TABLES

TASK PAGE

I. The Occurrence and Eelativ® Abundance of th© Gopepod Species in All th© Plankton Sample® «... Appendix

II* Stations Compared in Determining the 'Upper

Vertical Limits of Three Specie® #••..».»...«».« IS

III. Size Eangea in maw of Several Spool©a of Copepods

•Found in Dixon Intrance *.....*.*.».*.....,•.... IT

IV* The VertleaI /Distribution af Centropegea

.momurrlohi aa Indicated by its Oeourrenee in

Supplementary and Deep Hauls »»..•..«.»*.•,.#.•# 23 diaoaudafcaa. V, The Vertical Distribution of Tortanna

aa Indicated by its Occurrence In Supplementary

and Deep Haul a *»*».•««#*»»•.**•»*»*»**•*.«»»***.» 2*7

VI* Mas set Inlet Station 89 *• .#*«.»#..#..#*».«»..»**• * Appendix

VII. The Age Proportions of the Oopepodid Stages of

Metrldla laeens and Calanui flnmerohleua Appendix LIIT OP FIOtfHES

FIGURE PAGE

It Plankton stations taken adjacent to the Queen

Charlotte Islands by the Canoollm It during

th® summer of 1953 »..*.».«;».»»,».«,»•,•„.,..,.,»,, 3

2. The occurrence of Gepepod species in samples

taken from different depths to the surface ... 14

3# Tli® distribution of Faraea&anua, parvus ...... ».,.,» 18

4, The distribution of Aoartia elausi .**.*..,.,.». 20

5, a) The size variation of aaartia clauai in

Dixon Entrance

b) Currents suggested by this variation #«**•*»*«•*«* 21

@t The distribution of Oentrppagea acmurrlehi ...... 22

7» a) The size variation of Centropages momayriehi

in Dixon Entrance

b) Currents suggested by this variation ,•»»,.».»»,»-. 2S

8* ' The distribution of Tertanua dlaoaudatus #•.«*..*..»* 28

9. a) The viae variation of Tort anus dis.oaudatua in

Dixon Entrance

b) Currents suggested by this variation ... * 29

10. Th© relation of temperature to th© distribution of

Oncaea oonifera • • •»• »•« •. •.. 31

11. The distribution of .Oneaea oonifera ...... 32

12. The distribution of Corye&eus affinis .*#,«....•.*... 33

13. The vertical distribution of Ooryoaeus affinis 34

14. The distribution of Calanus f Inmarohloua ...... 36 FICRJHS PAGE

15. The vertical distribution of Galanus flnmarchlcua

off laden inlet in Dixon Entrance * • ....* 36

16. The distribution of Metrldla lueena 37

17 • The distribution of Eucalanus bungii , 38

18. The vertical distribution of three species off

laden Inlet in Dixoa Entrance ***...«*.#*•.#•*»•#*• 38

It* A proposed circulation of the surface water above

14 meters in Tasu Inlet. *... 42

20. A proposed circulation of the water between about / 14 and 30 meters in Tasu Inlet ...... 42 21. A proposed circulation of the deep water of Tasu

Inlet <«.<•»..•••.•..*»«*.•«..*•.«•.•.•«,.••.•••.. 43

22» The distribution of the deep water oopepods in

Tasu Inlet ant immediately outside ..•.*«..*.».».# 43

23* A proposed circulation of th© surface water In

Dixon Entrance 47

24* A proposed circulation of water between about 15

and 30 meters in Dixon Entrance .,....»..,.,....., 47

25. A proposed circulation of water between about

40 and 100 meters la Dixon Entrance •«#*«•.»**»,»* 48

26. The relative abundance and vertical distribution

of oopepods at station 80 In Masset Inlet over a

24 hour period ...... 51

27. The relative abundance and horizontal distribution

of Gentropages memurrlohl in Masset Inlet 52

28. The relative abundance and distribution of Acartja olausl in Masset Inlet 53 ill

FIGURE PAGE

29. The relative abundance and distribution of Oncaea

eonIfera In Masset Inlet ...... 54

30* The population- structures of letrldla lucena

at the stations in Masset Inlet 54

31. The horizontal ranges of several copenodid stages of

Metridla luoens in Masset Inlet ...... 55

/ ijwjtoarcrxon

Daring th© summer of 195$, the waters adjacent to the

Queen Charlotte Islands were surveyed In the O.G.M.v*. Csneolim

II under' the sponsorship of the Defence Be search Board' and the scientific direction of Dr* ft*F, Seagel and Mr. F.G. Barber.

Plankton samples were taken at each station (Fig, I) with physical data, in order to permit a study of the relationship of plankton to ©eeanbgraphlQ conditions, in the area.

One of the most striking factors became evident, when the deeper hauls were seen to contain different copepod species tn&n were ©aught in hauls from shallow water. This situation suggested that the species had certain vertical ranges some of which were in deeper water* further study determined the ver• tical distributions of many eopepod speeles. With this inform• ation, it was possible to study the factors effasting horizontal distribution*

Th© occurrence as well as the abundance of various' species appeared to be associated with great differences in salinity and temperature* The regions where species were abundant and present in all stages were assumed to be breeding areas*- Inere the eopepods were rare and represented by a few stages only,, they were considered, in many eases to be Individ* nals scattered from an adjacent breeding population.

This scattering in turn was th© result of another physical factor. The currents although not known at the time of study were suggested as responsible for the dispersal of individuals from breeding areas. Aa scattering seemed to be prevalent in several localities, it became possible to suggest the currents in these areas. 3

DIXON ENTRA J C E o

8< 7•/ * J. 86 96 • 93 99 90 n» ^> ' . / I 9 ( *~-r^ 5 4° 1 j .102 J j m 0? INLET >N

105106V L z' • .^Y Z ^T** / BASSET /i INLET t

\ HECATE STR; MT *

* ^ ^» * 107 t—^^^^

5 3° \-< « THETIS INL£T^^

TASU

INLET „; V

52°

13 3' j 13 2*" 13 1° 1, Figure Plankton atationa taken adjacent to the Queen Charlotte Xslanda by the Cancolim II during the summer of 1953. 4

METHODS AND MATERIALS

Plankton samples were taken between July 18th and August

8th in 1953, in the Queen Charlotte Islands area including

Dixon Entrance and Hecate Strait. The station positions are shown in Figure 1. At all stations indicated, vertical hauls were taken from near the bottom to the surface with a thirty inch diameter net having a number ten mesh* At about on© half of the stations, additional hauls were made from one, three or fourteen meters, to the surf see* • A ten Inch diameter net was used for these hauls* At station 89 in Masset Inlet, samples were obtained from water pumped through a hose from a discrete depth* The samples were preserved in formalin.

the samples were considered only qualitatively as no direst accurate measurements were made of the volumes of water filtered* An indication of faulty filtration was noted at some stations (69, 72, 73, 86, 87, 112, 114, 115, 116, 128) where ifi crest ells aorvsfiioa and Acartla clsnai were captured in the supplementary haul but not in the deep haul. This suggests that the large net used for the deep haul was clogged by the time It reached the surface and failed to capture species living near the surface.

Also, no attempt was made to take duplicate samples*

Many workers (Barnes and Marshall, 1951, and Hardy and Gunther,

1935) have found that variability between duplicate plankton hauls can he large, due to the patchy distribution of the plank• ton. Hence, In considering numbers of plankton animals in the samples studied, only gross differences ar© considered significant. s

The cop©pods were determined to species except for a

few genera found In th© deep water. Most wer© identified by

referring to Davis (1949) although Giesbrecht (1892), Sara

{1903) and Bsterly (1905, 1911, 1924) were also consulted.

Difficulties arose in the determination of a few species which

were neither common or widespread. In a few cases, it seemed

evident that farther systematic work is necessary in this reg•

ion,' For example, a species of Gaetanns Was found* According

to Jesperson and Russel #(1952) very few males of this genus have been described. Therefore, these specimen* are in need

of investigation. .•'

••As'the method of sampling did not Justify exact quanti•

tative calculations only approximate numbers of each species were determined. The numbers at each station were denoted by fomr terms. 8Sarett refers to approximately one animal in a cubic thousand centimeters, "few* to ten, ^common® to twenty*

five and "abundant11 to .fifty* As no definite numbers divided caaas one category from another, it was difficult in tea© to

decide which term to use, but wherever the results wer© crucial

the samples were reeheeked. BsM^Mm* Vertical

It was immediately apparent that the deep hauls contained

more speeies. This strongly suggested that different species

were living at different depths. Evidence indicating that

speeies occur within certain vertical ranges can be seen in

* Directors of Publication. Section referred to ia written by W. Verwoort. many systematic and ecological publications on the copepods.

Depth distributions are*given in general, hy Davis (1949),

Slesbrecht (1893) and Wilson (I9©0), while 5uruhaal (1953) has studied In considerable detail the vertical distributions of copepods in Japanese waters* In an attempt to'deduce this distribution "from''the ©eeurrsnee Of speeies in the" hauls,'the samples were arranged In order of increasing depth, fhe appear• ance ©f speeies in the deeper samples'gave an indication of the approximate depth at wfaieh they ©ocurred.' In order to present this data graphieally the samples were considered in groups of twenty-five* For example the first group included samples taken from th© surface to a depth of 10 meters while the '

second group included samples taken from slightly greater depths to the surface. For eaeh species the percentage of

samples in which It occurred in each group was considered. In

Figure 2. where a speeies occurred in a group, in more than fifty percent of' the samples it was represented by a heavy line,

If less, by a fine line* It ©an be seen in Figure 2 that

Olauaocalanus apuicornis' occurred in only the deepest group of

samples and In less than fifty percent of them* It is then represented by a thin line in the last group. Pauedoealanug ainatu8# on th® other hand, occurred in more than fifty pereent

of th© samples in all groups. Sense, It is represented by a heavy line through all groups*

The upper limits to the vertical distributions of the

Speeies living near the surface could be fairly well determined

by comparing th© results of the supplementary haul with those of the deep haul*"- The analyses of the species and their approx• imate numbers In the two hauls yielded important Information as to how restricted a species was to th© upper layer, if and when

It moved down and how the age groups were arranged vertically.

If a species were common in the surface haul and in the deeper haul, it was assumed to be living almost entirely at the sur• face, while-atspecles absent from the surface haul .but present deep in the -haul presumably occurred somewhere below the depth

of the surface haul* '

iome species, however, lived well below the depth® of

the supplementary hauls. In some localities where deeper sta•

tions were close together, it was possible to estimate the

approximate depth «hero the uppermost individuals occurred by

comparing adjacent stations, one with and on® without th©

species. The depth of th© station where the species was not

found was less than that of an adjacent station where it

occurred, and thla depth was taken as tho uppermost limit to

the vertical distribution of th® species at the second station.

For example, if Met.rid.ia lucena was common at station % j' with

a depth of 100 meters and absent at an adjacent station "b "at

50 aaefcera, then it was assumed to be living at atation'V'be*

low 50 metere. Although the results appear adequate, it is

realized that error may he present because of the dependency

of a particular upper limit on the depth of th© adjacent haul.

However, they seem workable and have yielded some valuable

Information. Horizontal Distribution*

In tho discussion* horizontal distributions have been depicted on small maps on which the occurrence of the speciea and its relative abundance are Indicated by circles. The dis• tributions are considered in the light of temperature and aalinity data as well aa geographical location and in a few eases, bottom topography* The occurrence of a species at a particular point was taken to mean one of several thingst if th© individuals were abundant, present in all stages and pro* duclng eggs, the conditions in this locality have been in the recent past and.are favourable for the reproduction of that species, if the individuals were rare and represented hy only a few stages then they were considered In some instances to be scattered from a larger population. In the latter case it is difficult to distinguish between a population which Is increas• ing and a group of Individuals merely surviving. However, each case is considered separately and ao overall interpretation is used.

With a clearer idea of conditions which are optimum and suboptimum for each species,' it becomes possible to visualize centers of reproduction and th® movements of individuals away from these localities, by the currents prevalent in th© area.

Dispersal was best studied in spec!©® which were neither widespread nor rare. Feeudcoalanua mlnutua and Qlthona helgolandlca were too common everywhere. The limits for sur• vival of these two are probably well outside the conditions in this area. Epjlabidocera amphltrltes and Aetidema armatua on the other hand were so few and scattered as to be almost uaaleao for a atudy of diaporeal* Variation in tfet alia of aopapoda btafuw a vary neeful ofittrlan fw dl»tla§«lahlag populfttioaa. Tha absolute slsa of adalt «©p«p©da haw bean found to vary with locality baaing 1958) and aeaaon im&y 1060)• In tho literature there la no Mieattotifenat th e else of the adult d«panda en tha length of tlma it h«« be«n ais adult* Cotkalderins tbt aiaea of the diff• erent; davelojpiaenfcal stage a of pavaral oopopoda (Jonaaon 1@M a and Stfbnir XttM) it la ardent that alee inereaaea oeosar dur-lng m® moult tafcatwn atagea«

III en attwapt to explain the variation of the alaea of •Suite* 0*»tng ©©italderafcragfeti ©Haerwtlo a %im% m iaereaee in teaperatare will prottoo* an ineremae in the rate of 4*«a&* opraent. 1« r a marks i);wt If a otipapod deireleped in cold water, it would eat ware than a ©opened developing in warm water under the sane food oonditlons. Ia the aiaa of any one stag® Oapettda on tha aitse of the pm&Lma atage aa well as e» food oanditlon* in the ye**nt peat* Baaing auggeeta that temperature, isflxjena* Ing tha langtt* «f ftndtag tine, and f@ed ewaaentration* affast* lag the fttnaant oonsuaad could &mm the else variations that h® ©neerved near Greenland*

In one area at one tine* those faatara would affeot th® • growth of all oopapada the mm* afeath*? or not tal.® effect varied, the net reault would be apparent in the aiae variation of the- adult* of that area* JSeoo* a wry ;nmrrow else range would be **pa*tad« ffhia was fatal to be th® oaae, first in

Metrldla luoana. Even if neither the past conditions are known nor their exaot effect on the slue of the ©opapod, tha 10 narrow size ran^e la one locality is ia Itself useful, as eopepods dieperaed from one art® mj im reeognltsed by their else*

la Dixon Entrance the else ranges of several apeolsa were determined In order to find the extent end direotlon of dispersal*, that* ipeeiee were measured from the tip of the head to the end of the sandal faunae, using an oenlar mlero- mUr* nnrted off in ,05 mm* taterwle* Slgaifi«*nt differences la the site ranges were apparent* These eould be used to detset direction of *@abt®i»Ing*

Harked diffartnaaa in th® proportions @f the age else see

Of a few apt**** was aoaaldvvwA in one or two esses to indloatw 4tatlnatt «eja when population %*n v but only the water seas in that ideality was ahown t® be distinct by else differenees In ©tfaer epeelee or tha preaenee of different speeiae. This Method waa mum effeetive in considering the diaperaad of the sub» smrfaa® spealea in whloh the age group* have a dafiiiite vertleal dlitribmtioa tha nearer fhe t young being the surfsee• preeenee of young only, at a station iadleeted that they had drifted away from above the adult® which lived in deeper water* &a this teehnifie waa

The tern population refers In this study to a group of animals of one speeies whieh has developed in one area at one time. It is also uaed in this sense by Barnes and Marshall (1961). U

mmhm

The water flowing past th© %t©©n Charlotte Islands ooaea from the northern port Ion of the Rorth Faolflo Drift Cswdrmp «J| aj. liW)# This broad diffuse current divides Just south of the lolaad* the northern, arm moving up the eeeeb has a fairly uniform temperature whioh fluctuates seasonally to. about aefeara hut rarely above degrees oentlgrs.de • 200 wanna t© 15

with thaae ta^eratur® etearaeteriatle® this are® mm be ©on- alderad In one of tiea^reaht1!.faunlatle sonoo (©ieebreeht 1898). la hag divided the plankton fauna into three geographical zonest the southern sold water, tha eantral war® water and the northern eold water* the last la Halted to the south by the 15 degree aantlgrato laothem* Seaee, th® waters being studied belong in this tone* OoMMa^eatly* the eopepods are mostly northern cold water epeeles* fhe almost complete absence of war® water apeoleo aaaea th® •laaalfloatUn difficulttoa @©naiderably» Thirty two ayodioa of oopooodi ware determined* These are Hated below*

«aai Acartia ol aieabrficht A*loiigirwodf (tiUjoMg) aratabue (Boeck) Aetidoua Brwdyidiua aimllie 0 (Sara) Salawe erletatua Kr^yer C. fiaaairohioiui (tunaerna)

6* tonsua Brady 12 #Candacla Columbia© Campbell

Centropages raomurri chl Wllley

Chlridius gracilis0 J&pran

Clausoealanua aculcornla (Dana)

-*Epilabidocera amphitrites (Momurrich)

Eucalanus bungil OlesbrecLt

luehaeta Japonic*. Marukawa

Eurytemora hlrundoides (Nordqviat)

Grasbairas sp«

Heterorbabdus proximus0 Davis

letridla longa (Lubbock)

1. luoena Boeek

-Faraealanus parvus (Glaus)

Pleur©mamma ap.

Pseudeeal&nu© aim bus (Ir^yer)

Ihinealenus nasutus® Siesbreeht - one specimen seen

Sooleolthrleella minor (Brady)

S* eubdentata. (Esterly)

Tertaaus diseaudatsua (Thompson and Scott)

aObryeaeua affinis If ©Mar rich

Oithona helgolandlea Claus

0* plumifera Baird

Oncaea conifera Giesbrecht

*OHDE-R 0g.B B4HPA0TXOQ3CDB4 Mlcroatella norveglca (Boeck)

M. rosea Dana

o probably 13 A few other harpactacoids were present In the samples hut as these were not common or widespread, they were not determined.

As mentioned before all these species are northern cold water forms, although a few are also found In warm water. Several are peculiar to the lorth Pacific. These are marked with an asterisk. The distribution of all the species at the stations can be seen in Table I (Appendix).

The vertical distribution of these species is shown In

Figure 2. A line in the figure indicates the occurrence of a

species at the stations having depths as indicated. As was mentioned before the stations were grouped according to depth.

The dark line Indicates that a species was found in more than fifty percent of the stations of the group indicated. Although

galanug finmarchlous was caught in a few cases near the surface, because it was more common in deeper water it was considered as

a subsurface form. Of the species which were caught in hauls

of 22 meters or more, one, Bradyldius almilis, Is benthic and

will not be considered as part of the plankton. Aetidiua

armatua and Epilabidocera amphitrltea are too sparce for further

consideration.

The upper limits to the vertical distributions of the

subsurface species could be roughly determined by comparisons

of adjacent stations, in one of which the species Is either

absent or rare. The compared stations are shown In Table II.

The depth of th© shallow stations are the depths of the upper

limits to th® species' distribution. These are seen to be

quite variable. This variability prevents the detailed use of 14

X* longa 0* aeaitorsia aaetamia Deep H*fe**oitafe0a« forma Blm®mmmm 0. c^XoatolM S« jspontoa C* arletava*

$n»*» A. HMtBI Surfaee o#. plunifera- Ponaa v. tumm §m fttmrnmhim®

c* tffiau —. M* F©gft , F# 1» p»»»nirundoidea s 0* eoaifev* Snrfae® i» norvtgia* Forms f« dlaeftudatae 0* wtm#*Uto& ; A* longtraait ______4*. aXanai • • tm miia&ttts 0« beXgoXan&loa

Bepfeh Rangaa,** 1*X0 14*20 83*48 44-10 ©*?-64l§

figara 8* Tha ooeurrenoe of oopopo4 apooloa la awttpXat taken froa different depth* to the aurfaoe, 15

TABLE II

STATIONS COMPARED II DETERMINING THE UPPER VERTICAL LIMITS OP THREE SPECIES

Calamis finmarchicus letrldia lucena Euoalanus bungii i Present Absent Present Absent Present Absent Sta* Dep* Sta, Dep* Sta. Dep. Sta. Dep. Sta. Dep. Sta. Dep. M M M M M M 64 44 68 25 97 35 90 36 81 135 90 36 104 75 103 36 83 366 86 91 83 366 86 91 09 91 72 53. 114 164 108 100 97 65 90 36 119 175 122 104 82 206 96 46 86 91 85 55 110 33 109 24 111 119 108 100 112 . 91 113 45 average depth distributions for any one area. Instead local upper limits have been used, except for one case (page H) for particular areas.

Finally, eleven species were caught only In th© very deep water, 87 meters or more. These stations are mostly off the shelf on the west coast and in th© deeper regions of Dixon

Entrance. The species found were not represented by great numbers and wer© not widespread, half of them wer© caught only in two or three of th© very de©p hauls. These species ar© pre• sumably characteristic of th© deep oceanic water which occurs close to the west coast and In Dixon Entrance. In the liter• ature (Jespersen and Hussel 1962) these species ar© termed oceanic, while th© others mentioned above are mostly nerltio.

The results of measurements of several species in Dixon

Entrance ar© recorded in th® following Table III. 17

TABLE III

SIZE R&IGES II MILLIMETERS OP SEVERAL SPECIES OF COPEPODS FOUND IN DIXOH ENTRANCE

Adult Males

Sta, A, olauai A. longiremis T, dlscaudatus G. mcmurrichi 2 99 0*95-1*01 1*53-1,80 1,43 98 0*70*1*00 97 1,73* 1.41* 71 •1,^0*1,06 p 75 1.86-2,10* 1.27-1*60 75 1.30-1.44 96 0.72*0*75 0*96-1*01 1,52*1*77 1.44-1.78 88 0,90* 90 0*72-0#78 0*9©# 1# 25*1,33 91 0*91-1.00 0*92-1,00 1.30-1*50 1*24*1.55

Adult Females

8t*'« A« olausl A, longiremis T. dlscaudatus 0. mcraurrichl

s 99 1*17-1*31 1,87*1.94 98 0*85-1.04 X. 62* 97 71 1,20-1*40 73 0.92-0*97 1,48-1.52 75 1.70* 96 0*90*0.93 1.14*1.35 • 1.63*2.40 1.52-1.83

88 1,20*1.25 O 90 0*88-1*00 - 1*15*1*25 1.45*1.69^ 91 0.95*1,12 1*09*1.27 1.35-1.57 1.40-1.72

*1 specimen measured

2-2 specimens measured 18

DISCUSSION

fhe horizontal distributions of the more common species

can he considered in detail, Each is considered separately,

because as a species, each has its own physiological limits,

seasonal fluctuation and vertical distribution.

Spceiea living near .the surfaces

Faraealanus parvus:

P. garyus was found in the upper 14 meters of water in

seven out of nine stations where supplementary hauls were taken

(Table 1 Appendix). At five of these stations the numbers caught

in th® deep haul approximated those in th© shallow haul, so it

was assumed that here P. parvus was living almost entirely at the

surface. At two station® it occurred slightly below 14 meters as

well as at th© surface, while at th© remaining two stations it

was rare and was caught entirely below the surface layer. This

species therefor© can b© considered

as a surface form rarely occurring

P. parvus was found in

large numbers at only three local•

ities (Figure 3.). In Thetis and

Tasu Inlets It seems likely that

P. parvus has Increased locally as

these are isolated populations, the

absence of this species at the sta-

tlons being indicated by the arrows.

Pig. 3. Th© distribution of Paraoalanua parvus 19

In Dixon Entrance, however, the population may have come from elsewhere, As there were no P. parvus In laden or Masset Inlets, it is possible that it could have drifted into Dixon Entrance from the north or th© east,

Thetis and Tasu Inlets have th© highest surface temperatures of the area sampled (Table I), As P. parvus is living mostly at the surface here, these temperatures may be correlated with Its abundance*

Glestorecht (1892) classes this species as characteristic

Of all three faunistio zones. However, he has stated that its northern limit ia at the 10°C. Isotherm, Although this limitation is an approximation, with a consideration of winter temperatures, stated by Barber and Tatoata (1954) to be about 7*7°0. in Dixon

Entrance, It is realized that the water temperatures in this area indicate that P. parvus is living here close to its northern limit, If this I® the case, then temperature as a limiting factor would toe expected to influence the abundance of P. parvus.

It is not suggested that jP*_ parvus cannot survive during the winter but it probably does not breed then, as the temperatures are below Slesbreeht's limit* However, In the spring as the water warms, breeding could commence* If waters In different localities warm sooner than In others, then these will after a time be popu• lated with more P. parvus*

Acartla clau.s.li

A. clausl lives immediately below the surface in most areas and does not appear to extend much deeper than about 15 or 20 meters. Only at two stations was it found completely below 14 meters. 20 The speeies Is most common

in three localities (Fig. 4.). Th©

greatest numbers were found in

Dixon Entrance and laden Inlet* For

some unknown reason It is absent

or rare from th© surface waters of

deep stations* As this species is

euryhaline, It may prefer low sal•

inity water found at the surface

near land where runoff supplies

fresh water.

Temperature, however, may

also have an important influence on

th© seasonal fluctuations of this

eopepod, similar to P. parvus*

Figure 4* Th© distribution Giesbrecht (1892) has noted that . of Acartia clausi . A, clausi. is characteristic of

warm and northern cold water hut Is limited to the north by the 11°0* Isotherm. Its profusion, then, may b@ du© at the time of sampling to th© previous as well as present existence of low salinity warm (11°C.) water.

In addition to the above factors, the effect of a scatter• ing from population center's Is evident in Dixon Entrance* A. clausi was stmdi©d here in more detail. By determining th© size ranges of th® animals at different stations It was possible to distinguish two separate populations and their distributions,

Th© results may be seen In th© following illustration (Figure 5).

Th© distinct separation between th© size ranges of the 21

Figure 5, a, Size Variation of Acartia clausl in Dixon Entrance b. Currents suggested by this variation 22. copepods at stations 96 and 91 is striking. This is taken to

mean that A, elaual at both these stations have grown up in

different environments probably in slightly different food and

temperature conditions (see page 9 ) and thus are considered as

separate populations. At station 90, tha males belong with the

population at station 96 while the females are a mixture of

copepods from stations 96 and 91. Station 98 contains a mixture

of animals of both sexes from stations 96 and 91, The mixing

and spreading of these populations suggests the currents

(Pig. 5) which may be responsible. These will be discussed

later In the account of Dixon Entrance as a whole.

Oentropages memurriehi.s

£. mciaurriehl was found

at 26 stations mostly in Dixon

Entrance and Hecate Strait*

have supplementary hauls, the

results of which give a fairly

good Indication of Its vertical

distribution. The following

chart (fable IV) summarizes

the results.

Although there are too

few stations at night, at these,

C, mcmarriohj especially the

Figure 6, The distribution young stages Is found up to the of Oentropages momurrlchl surface. During the day, there 23

fmm iv fBB VERTICAL' OISTKlSJTlOfl OF QhMTROF&ggS MGgJBftlOHl AS INDICATED m ITS OCGOSHBHOB II WPPLHMEST&HY AND DEBP~ItAULS

Above Below Station Depth ' iwtature Depth immature Tim© Meters Moo* only Meters Koa* only

£ * Few r » lure

below* it Is tome tendency for It to remain At this time, when Is aujtif**** anall popula* at the it Is represented hy the whole of a tlon or by the upward extension of a large population* It would Uvea teem,' then, that £. »e«irrlohi Just below the surface with Although tha younger stages npperaoet* at times it occurs above

14 metere* It shows a tendency to move down during th* daytiKte. Uvea Moat of the population., however, slightly below 14 meters. 24 '

£• mcmurrlohl Is most common In Hecate Strait. In Dixon

Entrance it is common only at on© station while on th© west coast it is rar© and scattered, represented' by only a few Im• mature specimens. This situation suggests that seasonal fluct• uations ar© responsible for th© differ©no© in numbers. Th© small separate populations on th© west coast and in laden Inlet would appear to he populations increasing under present conditions, which may have been present in Keeate Strait previously. However, the data does not indicate anything definite.

Scattering by currents does seem responsible for some of the rare occurrences in Dixon Entrance* Copepods from several

stations were measured. The results can be seen in the follow• ing diagram (figure ?)#

It has been suggested that 0. atoaarriehl is living

slightly below the surfaee, extending into deeper water than does A. clausi* thus being subject to different water movements.

In the western part of Dixon Entrance, relatively large

specimens of £* maiaurrichl ar© common.. These, however do not move past station §0* as the eopepode at this locality are well below the sis© range of those at station 96* Although it was

very spars© at station WI the one specimen was closer In sia©

to those farther west* The few copepods at station 90 have

likely corn© out of laden Inlet. These are small and can b©

traced westward into Masset Sound (station 73).

The ©astern part of Dixon Entrance contained very few

C. momurrichi, too few for measurements. Because of the pre•

dominance of young stages here, it does not seem likely that

they have com© from the west. Figur© 7* a) Th© size variation of Oantropage® moimrriohi in Dixon Entrance b) Currents suggested by this variation 26 Th© size rang© of th© male© In Masset Sound is fairly wid© Including sizes comparable to those in Masset and Haden

Inlets and at station 96. It is evident that th© small copepods at station 73 could have come from station 90, directly west, while th© medium sized individuals may hav© com© from inside Masset Inlet. Th© larger copepods her© are only com• parable in size to those at station 96. Because this species is so common at station 73, it is not conceivable that it has spread from station 96, through regions where it la scarce, unless perhaps, the intervening area has in th© recent past contained more £• memurriohi.

Although the problem of seasonal fluctuations is present also in this speeies, some Indication of scattering by water movements ia suggested by th© size rang© variation and population structures of this speeies in Dixon Entrance.

The currents Illustrated will b© discussed in relation to others in the account of Dixon Intranee.

Tortanus diseaudatusi.

Th© vertical distribution of this species can b© reasonably well deduced.from the twenty-flv© stations which have supplementary hauls* In Table ¥ on page 27 the stations are arranged in a time sequence. The depth of th© supple• mentary haul is given with th© approximate numbers of copepods. Below the depth of th© shallow haul, th© numbers are based on th© results of th© deep hauls.

The species tends to remain .below 14 meters although

It ean survive in the surf's©© water* The eggs ar© laid both 27

TABLE V

THE VERTICAL DISTRIBUTION OP TORTAMOS PISCAPPATHS A3 INDICATED BY ITS OOOOBREHCE IH StlPPLiSMEllTARY Alt)* BEE*' HAULS

Station Tim® Above Below Depth Hot* Dopth Bos.

3 © 72 0642" 3 r 4 e 126 oaoo 14 r 73 0800 3 j. 64 0810 1 2* 94 0845 14 f 71 0900 ' 1 e 69 1055 1 1 © r (imm) 127 1130 14 © all stages 101 1215 14 • f ©s 1315 3 f 114 1400 14 r 128 1415 14 f 14 f 87 1500 3 r A 129 1515 14 o 14 Off Adam Ek. 1630 14 f 121 1630 14 r 82 1645 10 f f © 115 1710 • 14 rt imm. 8S< 1715 3 * * e 130 1730 14 f 111 1800 14 V 83 1900 - 10 e 131 ' 1930 14 r, 1mm, 14 r, ItBBU 116 1945 14 imm. 14 f 68 '201$ 1 c 70 0145 1 c 110 0225 14 r

above and below 14 meters but th© young seem to occur just above

th© adults.

Johnson (1934a) has Indicated that this speeies is very

widespread although rarely becoming abundant. Its profusion In 28 th« area.sampled could not be related to the physical character•

istics of water at twenty meters* As this species is a primary

carnivore, the presence of suitable animal food may toe respons•

ible for its abundance, especially when the survival of the

very young nauplii depends on the presence of small protozoans

in the surrounding water. As the food conditions could not be

estimated# the reason for its abundance In certain areas is

still questionable*

The species, however, is very widespread (Figure 8), a

result perhaps of Its vertical

distribution* Occurrence mostly

below 14 meters enables the adults

to remain Inside inlets with shall•

ow sills for example, laden Inlet

as well as In the slower moving

subsurface waters outside the in•

lets* On the other hand its

occasional presence in the sur•

face layer brings It under the

Influence of faster currents*

The water below 14 meters however,

must toe responsible for most of

the dispersal of this species.

Figure ©* The distribution This dispersal was evident of Tortanus dlscaudatus "• ' "" In Dixon Entrance where T* dls•

caudatus was measured* The results of this are seen In Figure

9 a* Although scarce In Dixon Entrance it is distinctly

larger her< than In laden Inlet. Because of their similar size

ranges, the copepoda In Dixon Entrance are considered to toe one Figure 9 a) Tto.© sis© variation of Tprtanua digCaudatua in Dixon Entrance b) Th© currents suggested by this variation continuous population in which the adults have been subject to th©.same past conditions* There is only a slight suggestion in the size of the female at station 72 that a few Naden Inlet cop®pods ar© spreading out into the open water. On© of th© two cop©pods measured in Masset Sound was, however, unusually large. It could not have originated from inside the inlet because her© T. diaeaudatua is extremely rare. Besides, th© one specimen that was measured from her© was much smaller than that in th© sound* The other copepod fell within th© sis© range of the Dixon Entrance cop©pods* It could have originated from station 96 or less likely from station 99. An the sisse variation of Q. mopurrlehl also indicated a subsurface inflow of Dixon Entrance water into Masset Sound it la quit® possible that this is also suggested by the distribution of T. dlaoaud- atug*

Oneaea. conifer*, t

0. conlfera lives in a fairly wide range of depths, ^rom an analysis of the results from station 69 in Masset Inlet

(Table ¥1 appendix) it is evident that this species Inhabits water from 75 meters to th® surface* Th© presence of eggs at

SO or 60 meters ia strongly indicative that conditions only her© ar© favourable for breeding* In Tasu Inlet it also occurs in th© subsurface as well as th© surface water* Th© eggs here ar© present in hauls taken from 14 meters* Proa th© tempera• ture data of both localities exemplified in Figure 11, It Is evident that th© eggs ar© being laid at a temperature of about

11°0. 31 All th® stations where 0, eonlfera occurs have tempera•

tures allowing breeding. In the following Figure 10 are

arranged the temperature curves for stations where 0, eonlfera

was A) common or fewj B) rare and C) absent. The last group

Is made up of stations taken in west coast inlets. These were

chosen on the grounds that 0, eonlfera seems to typify Inshore

waters (Figure 11), The stations where 0, eonlfera is,present

are all characterised by a,high surface temperature, above

13*5°0V* Of the stations where 0, eonlfera ia absent but hav•

ing temperatures at which it can breed (127, 128, 129, 10§* 108,

109| 110| 117) only three have high surface temperatures and

these (117, 110, 109) are shallow, having very little bottom

water below 11°0*» It would seem* then* that £» eonlfera he-

comes -common In localities where there is a fairly deep layer

TASU INLET MASSET

on V ABSENT

I 00 M 10 c TEMPERATURE SCALE VERTICAL LINES AT II C

Figure 10. The relation of temperature to the distribution of 0. eonlfera 32 of water below 11°C. as well as warm surface water. Perhaps the development of the young requires a high temperature. This apparent dependency on warm surface water Is sufficient to limit 0» eonlfera to inlets In this area, Nowhere In the out• side water does the temperature rise above 13.5°C..

0, conjfe.ra is represented also by a few nohbreedlng

Individuals at other stations (Figure 11), On the west eoagfc four of these stations where eggs or both eggs and adults were absent are seen to tee slightly north of the main population centers of Tasu and Thetis Inlets* The distribution suggests scattering by a northward moving current in this area* Froa th© Tasu Inletf 0, eonlfera Is presumably swept out in surface

water and carried northward.

Only a nonbreedlng part of the

population moves out her® as no e egg sacs were found at station

124, Its rarity farther north

may Indicate that it Is dying or

being widely dispersed, In three

Inlets to the north, however,

£* eonlfera. Is represented by a

few Individuals in the deeper

water below 14 meters* If the

circulation of water In these in•

lets ia.typical, then the surface

water is moving out and being re• Figure 11. Distribution of Oncaea eonlfera placed by an inwardly flowing 33 bottom water, fhe unusual ooourrence of 0, conlfera in th© d©©p water her© perhaps suggests that at the time of sampling

it was being carried in th© deeper water into these inlets from outside.

Scattered individuals also occur in Dixon Entrance* As

these have not drifted out of lasset or laden Inlets, it would

seem likely that they come from north of the sampled area.

Coryoaeus affinlet

jC. affinia is distributed much like 0. conifers. Breed•

ing population ar© present in Tasu and Thetis Inlet (Figure 12)

although they ar© not as obvious•

ly breeding as 0. conifera* How•

ever, th© relatively large number

of this species in Thetis Inlet

ia assumed to have .arisen there.

In Tasu Inlet a female carrying

an egg sac was seen* 'Th© rarity

©f ®gg sacs may merely mean that

the copepods are just beginning

to mat© and that th© breeding

cycle is attuned to seasonal

fluctuations. C. affinia Is more

common in Puget Sound where pop•

ulations with many females carry-

Figure 12. Th© distribution ing egg sacs have been noted,

of Coryoaeus affinia 34

Whether or not _0* affinlg breeds In the same condition as £• eonlfera, It Is difficult to say, It la however, common where the warmest surface waters of the area are found. This may be significant to the development of the young stages, although this species is not always found in the surface layer.

Another factor Influencing its distribution becomes evident with a consideration of Tasu Inlet, C, affInia seems to be flourishing in the long, arms hut does not spread into the main part of the inlet* 0. eonlfera on the other hand, moved right out of the inlet, A reason for this lack of dispersal may be seen In the vertical distribution of 0, affinis. It Is absent or at times rare, in the surface water, while £* eonlfera is always present there (figure 13),

119 S X • F S a

1 w a F 0

Time 1330 1630 1815 1030 1045

Figure 13* The vertical distribution of Ooryoaeus affinis

It might be suggested that C, affinis in occurring in the deep layer only for a time is kept in the arms by an inwardly flow• ing bottom current* Its mere lack of dispersal at any rate would suggest that this species might be able to Increase In other localities but has failed to reach them*

There are some apparently scattered £« affinis at five other stations* The locations of these, however, give no clues 35 ' to th© origin of the individuals* 'I'hey may have come from out• side the sampled area*

Subsurface apealeat

fhe following three speeies, £. fInmarohlcus* M. luoens aad £• hungii, ar© limited to th© deeper water as seen In

Figure 2 and in Table I(Appendix). Th® vertical distribution of th© age groups of the first two species was determined from the data of station 89 in Masset Inlet,(Figure 26, page-5 7,

Table ft, -Appendix), In both, the young live, closer to the surface than the adults* Both sexes of M. lucens live at approximately the same depth* The male C. finmarchieus, how• ever, appears to occur' In deeper water than th© female. Th© absolute depths are not considered typical, as M, luoens adult© are certainly limited to water deeper than 30 meters In Dixon

Entrance* Because of the scarcity of E. bung|i,, it was not possible to determine th© distribution of th© eg© groups*

Station 89 data also indicates that if* lucens and C* finmarchlQUs perform a diurnal vertical migration, the latter moving up from.deeper water, close to th© surface at night.

Other authors {Clark, 1933 and Mieholls, 1933) have found this same behavior in these two sps©!©a. According to Bsterly

(1911b), however, Buealaa.ua elongatua, a-close relative of E, bungjj, does not migrate vertically In San Diego Bay. Whether or not this is typical also of E. bungli In th© Queen Charlotte area is not known. This species, however, is not found in th© shallower hauls which capture 0. fjnmarehjoua and M* luoens* 30 '

Oalanua finmarohiousi

The horizontal distribution

of this species can b© seen in

Figure 14# fhe restriction of the

adults to the deeper water is very

noticeable, as well as the wider

distribution of th© younger stages.

Although it can not be shown that

the young live in th© shallower

water in Bixon Entrance, it is quite

possible that during their vertical

migration they come up into the

surface waters long.enough to be

Figure 14. Th® transported onto shallow areas* Distribution-of galenas f inmarchious This process may be visualized in the following diagram. (Figure 15) Illustrating the vertical dis• tribution of £. flnaarchicu® at th© locality indicated by the line in figure 14*

Figure 15, The vertical distribution of Oalanus finmarehloua off Naden Inlet In Dixon Entrance 37 This effect ia also noticeable in Tasu Inlet, where the young move into the shallow arms away from th© main population in the deep part of th© inlet. In both these places, scattering Is probably the result of currents just above SO meters.

Metriala luoenst

The distribution of M» luoens (Figure IS) suggests that

it is limited to deeper water than is 0. flnmgrchleua* The upper

limits to its vertical rang© in different areas (Table II) also

indicates this* Its restriction to th® deeper water is very

likely responsible for the lack of dispersal of the young stages.

In only two localities, off Baden Inlet and In Tasu Inlat, is this effect evident*

Euoalanua bungli* As this species was so rare, no conclusions could toe drawn from

th© age distribution®. stag© V"

copcpodids and adult females wer©

present in nearly all samples in

which It was found* 'Ihere is th©

suspicion, however, that this

species is more common than the

plankton samples indicate*

Johnson (1943) has found that it

is quit© capable of evading plank-

Figure 18* Th® dis• ton nets. tribution of Metrldla lueena 58

Th© upper limits to its vertical distribution (Table Ii) is very similar to that of M. luoens. In spit© of this, this species does not spread onto shallow areas (Figure 17). When the vertical distributions of the three species are considered together (Figure 18) off Kaden Inlet, this effect Is noticeable.

The fact that it probably does not migrate upward into an on• shore current, evident In the distribution of th© other two species, very likely accounts for its limited distribution.

ST. 91 92 90 97 81 DEPTH METERS

h50

C-F INMARCHICUS MLUCENS MOO

- E . BUN6II

Figure 18. Th© vertical dis• Figure 17. Th© distribution three of Buoalanus bungil tribution of species off Naden Inlet in Dixon Entrance 39

Part 2j Currents suggested: by the dispersal of Copeooda

The distributions of all the species including those which are rare are considered now in several areas, with suggest• ions of possible current patterns* These areas are in order;

Tasu inlet, Dixon Entrance, Masset Inlet*

Tasu InletI

Tasu Inlet Is fairly large and highly productive body of water on the west coast ©f Moresby Ialand(Figure !•)• At the tine of sampling its plankton consisted largely of copepods*

The composition of Its fuana, however, reflects the influence of open ocean water, by the presence of salps and siphonophores, as well as water from shallow areas characterized by pelycepod

larvae. In addition to this the presence of three long bays

make this inlet a complex body of water* The results of seven

deep plankton hauls as well as five supplementary hauls along

with considerations of the physical data and topography do,

however, give some idea of Its circulation.

The main part of Tasu Inlet is large and relatively deep

(Figure 21)• It Is separated from the open ocean by a narrow

sill, with a depth of 30 meters* Towards the heads of the three

bays, th® depth decreases to about 30 or 40 meters* bright In•

let, however, has a deeper pocket (maximum depth - 175 meters)

behind a sill of 50 meters depth.

Surface temperatures are high, up to 19°C. in Botany

Bay, This warm water is also present In the main part of the

inlet but not outside the mouth, fhe temperature, however, de•

creases sharply with depth, water at 20 meters being around 40 1Q0G., fhe deeper water at station 118 Is near 7°C, The

salinity also Increases sharply with depth from about 28^oo

to 32°/ oo at 20 asters becoming as high as 33 In the deeper

water at station 118. The conditions at th© surface suggest

that there has been an unmixed slowly moving layer of fresher

water there for some time, during which It has warmed consider•

ably.

The distribution of surface plankton, although scarce,

does suggest some outward flow of surface water. Two rather

restricted species common in Tasu Inlet, 0. eonlfera and J?»

parvnf, are found In all surface samples although the majority

occur below 14 meters. Only two other species, 0. helgolandlca

and P. alnutus were also consistently found at the surface, but

as these were so widespread It was not possible to determine the

centers of population Increase. 0, eonlfera and P. parvus

seem to breed In the three arms (Figure 19). They occur In less•

er numbers, 0. eonlfera without its eggs, sacs at station 118.

0. eonlfera only reaches station 124 presumably via a surface

current* Is the temperature ia low and the salinity high here,

considerable mixing must have occurred between stations 118 and

124. The presence of 0. conifera suggests that some of the mixed water has originated from the surface at stations 118*

A surface outflow from Wright Inlet and Botany Bay is also sug• gested by the distribution of £. affinis, represented here by a few individuals (Figure 20).

Species living below 14 meters as well as in shallow water are apparently limited to the bays (Figure 20)* Although these copepods are represented by few individuals, their lack of 41 dispersal suggests that water between 14 and 30 meters is not moving out of the bays. Alao^the abundance of 0, conifers

and P. parvus* which live mostly below 14 meters implies that

very little water at these depths is moving out*

The bottom water of the arms may be typified by the

presence of G, fjnmarohlcue. In Figure 21, the distribution of

the adults and late copepodld stages is seen to be in deeper

water only. The young, however, living above th® adults appear

to have spread into the shallow bays indicating an inward flow

of water just above 50 meters and possibly up th® 25 meters.

M. luoens seems to be restricted to the deeper water at station

118* The presence of a few young individuals in the deep pocket

at station in Wright Inlet, however, suggests that strays ore

being carried to a slight extent over the sill et about 50 meters*

The remaining speeies in the deep part do not seem to

scatter* This suggests very little vertical movement of the deep

water*

The relationship of the deep water inside the sill to that

outside Is illustrated by a comparison of stations 118 and 124

(Figure 22}* Five species live Inside below 100 meters, M*

luoens and S. minor being uppermost. Except for M* luoens all

are represented by fewer individuals her© than outside. At

station 124, an additional five species occur presumably belong•

ing to the deeper water. The presence of stage V oopepodids and

female adults of E* bungii is of considerable importance. By a

to its vertical distribution Is near 38 to 100 meters. This

Figure 19, A proposed circulation of the surface water above 14 meters in Tasu Inlet

Figure 20, A proposed circulation of water between 14 and about 50 meters in Tasu Inlet 43 CALANUS Fl N MARCHICUS OoCO AO" L T S COPEPODID STAGES l-V

METRIDIA L-UCENS ADULT DISTRIBUTION C0PFP0D1D I- I I I DISTRIBUTION

•o- o-oo -c^r;- • v •oo- o-o -o-o c •o--— —o-o-o-o-

o---o, oo-o-o-o-o* -o-o-o -o1"

Figure 21* 4 proposed circulation of thedee p water of Tasu Inlet __,

50-1

175- Y DEPTH

METERS 340

600 Figure 22. The distribution of the deep water oopepods in Tasu inlet and immediately outside sill depth. As S, bungll does nob occur Inside the Inlet, it may be said the water ;Jusfc below sill depth la not entering the inlet at the present time nor has llkoly done ao in the recent past.

Further evidence for this Isolating effect of the sill may be seen in the population structure of S. japonioa. The rare individuals at station 118 were all oopopodids at stage V*

Outside stages XV, V as well as female adults and eggs were found. The existence of rare Individuals of only one stage In* side the inlet suggests that thee© have perhaps been carried into the inlet at some time but at present are separated from those outside. According to Campbell (1934) E. Japonica breeds

In th® deep water at 200 to 400 meters* Here also, the young develop* It cannot be assumed then ,the copepodlds inside the inlet arrived there at a previous time via an Inwardly flowing current which carried a few young off the top of the 1* Japonica

population outside* Although it seems likely that water 'below

the sill depth has at some time in the past moved up and over

the sill, It - la not doing so at the time of samplIn(S* Any water

moving into the inlet must be from a depth of above 20 to 36

meters*

In this analysis, it la suggested that a slow surface

current moves out of the arms into the main part of the inlet

some of It flowing over the sill. There Is some movement of

subsurface water into the arms at 20 to 50 meters. The deep

water in the center of th® inlet Is not mixing vertical and at

the time of sampling Is distinct from the deep water outside

the inlet* 45

Dixon Entrance1

The water Immediately offshore, north of Graham Island

ia sufficiently well sampled, to be Investigated in detail.

The presence of large areas of unsampl.. d water to the north and

west make this analysis vary difficult. The currents proposed

are, thus, only suggestions but they do Illustrate the possibil•

Dixon Bntranc® has a narrow, shallow shelf (figure 25).

About 20 miles from the shore off linden Inlet the depth increases

to 300 meters* Only on® sample was taken in water this deep

about 5 miles north of Lang&ra Island*

The salinity ranges from about 30foo to 35°bo st the surface*

The deep water has a fairly uniform salinity of about 33?oo«

pods will be considered In three groupsS surface to 10 or 15

meters (figure 23), between 15 and 30 meters (Figure 24) and

below 30 meters (Figure 25)•

The surface movements are suggested by the distribution

water indicates that this Is a somewhat separate water mass and

tribution of M» norvesica. This species also occurring offshore 46 from laden Inlet may possibly indicate an onshore surface current here.

An eastward movement of water at 15 to 30 meters ia also evident in the size variations of £. mcmurriohi and f« dlgoauda* tug (Figure 24}, the lengths of these copepods being comparable right across the coast* Some flow of water out of Maden inlet is also indicated but this seems to be much less than th® out• ward flow of surface water* Because these species are so scarce It is impossible to Judge whether or not they move north.

However, a separate water mass In the east Is also implied by the presence of large A» longlremia, above the size rang© of those found In the western part* Also the population of £» aeaurriohl, composed almost entirely of young animals may be different to that in the west*

fhe scarcity of adults in this area indicates that in• dividuals from the large population in Masset Inlet are not moving out and eastward* since it is made up of all stages in• cluding many adults* ®n the contrary, the large size variation of £. mcmurriehi In Masset Sound Implies that some at least, , have come froa farther west (station 06), and the entrance to

Baden Inlet* and a few possibly from inside Masset Inlet*. The inflow of slightly subsurface water into Masset Sound Is also

Indicated by T. dlscaudatus, a species extremely rare in Masset

Inlet.

Movements of the deeper water (Figure 25) can be visual• ized as responsible for the spreading of the copepodid stages of

C. finmarchicus and 1* lucens onto the shallow areas. 47

Figure 23* A proposed circulation of surface water in Dixon Entrance

Figure 24. A proposed circulation of water between 15 and 30 meters in Dixon Entrance 48

Q C OMMON

O HARE

$*S#tj»» 25. A pro-pooed aireulation of mttr between about 40 ' and 100 maters In Dixon Intranae

eee» be &• t^mr^m t© living slightly above M* .^OOQI aa its young are spread onto mat of the shallow areas* An example of tfel* was aoea In Figure 13* This aaattaring pmmmbtj ln- dioaiea an onshore isovament of water at aboat 40 ©r even 80 meters, fh* spread of II* Ittoena1 young onto the eholf in only one plaee, opposite laden inlet indicate* an exoeptional on- ateore ©xtrrent news at abont 50 a*tors* UpwaUimg in this region ia ale© suggested by the appearanee at station 81 of £. orlstafcns* a apaoiea otherwise occurring in atieh. deeper water (station 83) from 364 staters* This specie a does net occur at station 88 at

a depth of 806 meters. Of spools 1 note la tho spread of very young C» finyreh* Icaa into laaaet Sound (eopepodid stages 11 and 111). The origin of these oould only he the open water, as only stage 7 being found Inside Masset Inlet. The presence of these young

stages here along with specimens of 0. acaturrlohl and T* dls•

caudatus confirms the idea that water slightly below the sur•

face was moving into Masset Sound from th® outside at the time

of sampling*

Masset Inlett

Masset is the largest of the Inlets studied (Figure 1)*

It 1® about twenty miles long and five miles wide* The western

part situated elose to high mountains is the deepest, about 80

meters as sounded from station 78 (figure 27)* Towards the

eastern region the water shallows to twenty meters. The narrow

sound opening Into the eastern part, extends for about twenty

miles with a depth of twenty meters before opening into Dixon

Entrance*

In the deep water was unusually low* At the surface, It was

22foo* Increasing slightly at aid depth but decreasing again

towards the bottom* Although there are many rivers entering

the Inlet from all directions, the Yakun River entering the

southeastern corner from a large drainage area to the south Is

thought to be the main contributor of fresh water, The low

salinity near the bottom as well as the length of the shallow

sound make thla inlet very interesting.

The inlet was surveyed on th® 20th of July* Both a deep

haul and a supplementary haul were taken at each station.

Station 89, however, was occupied for 24 hours on July 24th. 50

A supplementary haul, pumped hose samples and a deep haul were taken four times during that period*

Ten species of copepods were found in Masset Inlets

C« rocmurrlehi P* minutua A. longlremla,

T. discaudatus A* clausi C. finmarchious

S* amphltrites 0. conlfera 0, helgolandlca

M* luoens

Inlet* Only rare specimens of E. aaphitrites and T. diaoaudatua.

factors influencing their distribution,

Shows the relative abundance of species at different depths over

a 24 hour period. Three species £. mcmurriohi, A* lonqlremls,

and A. plaugl are living near the surface * A. lon^irernla- seems

to occur near three meters here* At other stations It occurs

meters*

distribution and relative abundance Is illustrated In the follow•

ing diagram (figure 27).

The low salinity surface water, If Massot Inlet is typical

of most Inlets with a fresh water inflow, would tend to move out

TIME

0015- 034 5 300 -1536

Figure 26. The relative abundance and Vertical distribution of copepods at Station 8® In Masset Inlet over a 24 hour period. 52

Cj COMMON O PEW RARE

Fifty* 17* The relative abiandaaee and horUontsii distribution and reprodueing in this layer* It ©euld not become abundant where tea aurfeae water was teeing rapidly replaced. .g.ttOMai'glaM would aero UMgr hoeoiae ooonon in slowly moving water* Its abundante suggests a slow movement of aurfaoa water and the possible eacietonee of an eddy in the inlet* £• olaufli. unlike tho aforementioned speolea lives en• tirely in tha surfaee three liters* It ean be seen from Fifu* 28, that it occurs nost oetawoillf opposite the mouths of large bays* previous claual AS aeon in results, 4* is often eowon in b by Also vortical *ya.f typified Saden Inlet* the distribution stakes it subject to tho outward flowing surfaee water* It Is quite possible then, that A# olaual is more abundant in the bays opening into iaaset Inlet* If ao, those oepepods would move out into the mtm part and aeaouat for the large numbers st Station* 77 and 78* fhe other three spoelea are most abundant in the deeper water although they do occur near tha surface. 0* eonlfera and JM. iaoena oeour in fewor numbers near the surfaee but Figure 28* The distribution of Aeartia clausi in ttaaeet Inlet.

C. f inma.rob.ieua approaches the surf so® only at night* These speeies

may indicate th® movements of the deeper water*

Although. j>« conifers lives in the whole water column,

near SO meters and in the deep vertical haul, Free ®gg sacs

were also noted in these samples* As this species, character•

fallen off females after the sample was collected. This evidence

suggests' that £# conifers is reproducing in the deeper water at

0, conlfera* however, ia found in lesser numbers and without

must drift westward away frost their origin. 54

Figure 29. fhe distribution of Onoaea eonlfera

The vertical distribution of M. 3,uoen,s is similar to that

of 0. eonlfera. The adults live at 30 to 50 meters, while the

young live above this and «re continually present even If scarce

In the surface layer, figure 30 (Table VII Appendix) Indicates

STATIONS 77 76 7 8 74 7 5

noiW ungift ittuffig TTLMJSYM mmgYvi

DEVELOPMENTAL STAGES Figure 30. The population structures of Metrldia luoens In ° Masset Inlet 55 This data is presented also in Figure 51. Th© extents of th© distribution of adults and copepodlds is Indicated. It can be

copepodlds in stags v" range farther east and copepodlds stage I cover th© whole sampled area. A® only the young ar© dispersed,

Figure 31. The horizontal distribution of several oopepodld stages of istrldia luoens In Masset Inlet

Oalanus flnparchieua is represented In Masset Inlet by

copepodlds in stag© ¥ although a few adult females were seen as well as an occasional oopepodld stag© IV. It occurs entirely at

stations 77, 70, 75, 89 (Tabl© TO Appendix). Although It does move up to the surface at night, It la not dispersed, as Is M.

luoens, over the rest of th® inlet. Hence the current which

spreads the young of M. luoens must not be very fast or steady

as It does not cause C. fInmarchlous to spread while the species 56

Is near the surface*

Th® three species living in the deeper water appear to he isolated in Masset Inlet by th© long shallow sound. Two of them,

M* luoens and jO. conifers are reproducing at the time of sampling but it is doubtful that G* finmarohious is doing so. This specie a is mostly represented by stage ? copepodlds, a few adults and an occasional stag© IV oopepodld. It Is very difficult to say whether these were washed into Masset recently or whether they have been there for some time. It seems possible that th© very young stages of £. finmarohious. may have been carried Into the inlet. At th© time of sampling It I® present in its very

young oopepodld stages la Masset sound* It is not impossible

that a strong Inflow into the sound could bring a fair number of

this species into the inlet*

In sumnary, It seems that there are no definite rapid

moving currents in Slasset Inlet* As species living near the

surface are able to reach large numbers by reproducing, it is

reasonable to suggest that very little surface water Is moving

out over the sound at the time of sampling* There is some

indication, however, that surface water is moving out of the

bays. Also there seems to be a slight eastward movement of water

above 50 meters* Apparently very little water is moving into

SUMMARY. AID COHCttTSIOHS

Thirty-two species of copepods .were identified. All were characteristic of northern cold water. These species were found to have certain vertical ranges, some occurring only In the deep water* Hence, fewer species were encountered from hauls at shallow stations*

With a consideration of vertical distributions, the relat• ion of copepod distribution and abundance to physical conditions was studied. Temperature was found to Influence th® abundance of several species living near the surface. Aa these species were limited to the north by temperatures present in th© area during the winter, It was suggested that they became abundant only in th© summer and first in localities which warmed early. It was also evident that several species living In deeper water could breed only In the low temperature® there, thus not occurring In large numbers in the shallower water. In addition to temperature low salinity seemed to correlate with the presence of one species known to prefer water of low salinity. It la apparent, then, from this study that physical conditions have some influence on the presence and abundance of copepod® In the Queen Charlotte area.

Dispersal was also seen to influence distribution. The scattering of a species from its breeding area could be traced and currents responsible for this are suggested. In lasu Inlet, the extent of surface outflow and subsurface Inflow are Indicated as well as th© Isolation of the deep water Inside th© shallow , 58 sill from that outside* In Masset Inlet, th© surface outflow was not outstanding, instead, th© existence of slowly moving addles seemed evident. Species living In th© deep water her© also appeared to be isolated by the long shallow sill. Although no inflow from Dixon Entrance Is evident at th® time of sampling, it

Is suggested that periodically a fairly large amount of water moves Into Masset Inlet from Dixon Entrance*

A study of Dixon Bntranc© indicated an eastward flow of surface water as well as a movement of deeper water onto the shelf particularly off Naden Inlet*

This study although exploratory has indicated some of the factors which need to be considered la future plankton studies*

It has illustrated the biologist's ne©^ for knowledge of physi• cal conditions, ©specially the movements of water which have been shown to have a considerable effect on th® distribution of copepods.

Also many problems concerning the plankton animals them• selves ar© evident. A more basic knowledge of their seasonal fluctuations, vertical migrations and physiology Is required for this area* It is felt that la order to solve these problems, th© plankton should be studied as such and not as supplements to physical studies* A© this study has shown, copepods have poss• ibilities in current determinations but these will not b© realized fully until more Is known about th© animals themselves* 59

ACKNOWLEDGMENTS

The author wishes to thank those who collected the samples,©specially Dr. R, P. Scagel and Mi*. P.G. Barber and the organisations which made th© cruise possible, th© Pacific

0c©apograph!e &roup and th© Defence Research Board. Thanks also go to fellow students including several at th© University of Washington.

BIBLIOGRAPHY.

Barber, P. and S. Tabata, 1954. The Hecate Strait oceano- graphie project. Prog Rep. Pac. Coast Stat., Fish. Res, Bd. Canada no. 101:20-22.

Barnes, H. and S.M, Marshall, 1951, On the variability of replicate plankton samples and some applications of "contagious" series to the statistical distribution of catches of restricted periods. Journ. Mar. Biol, Assn. 308 233-263. Campbell, M.I., 1934, The life history and post embryonic development of the copepods, Calaaag tonaua, Brady and Buohaeta Japonica Marukawiu #ourn." Canada Biol. - M. npir Clarke, G.L., 1933. Diurnal migration of plankton in the Gulf of Maine and its correlation with changes in sub• marine irradiation. Biol, Bull, 65:402-436. Dahl, F., 1893. Plueromamma, ©In Xrebs mit Leuchtorgan* Zool* AM. 16:104-109, Davis, C.C., 1949, The pelagic Copepods of the northeastern Pacific. Univ. Wash. Pub, in Biology. 14:1-118.

Digby, P.B.S., 1950. The biology of some planktoule copepods at Plymouth. Journ. Mar. Biol, Assn. 29:393-438.

Ekman, S., 1953. Zoogeography of the sea. Sedgwick and Jack• son Ltd., London* Esterly, CO., 1905. The pelagic Copepods of tha San X>i©ge region. Univ. Calif* Pub. Zool. 2:113-233.

Esterly, 0,0., 1911b. The vertical distribution of Supaligns eiongatus in th© San Diego region during 1909* "oniv. Calif,Pub. Zool* 8*1-7* Esterly, CO., 1924, The free swimming Gopepoda of San Francisco Bay. Univ. Calif* Pub. Sool. 26:81-119,

Pish, CL., 1936 a. The biology of Calanus f inmarchicus in th© Gulf of Maine and Bay of MndyT" Biol. Bull. 70: 118-141. Pish, C.L., 1936 b. The biology of Psuedocalanua minutus In th© Gulf of Maine and Bay of Pundy. BTolT Bull. "70s 193-216, 61

Furuhaai, K., 1953. On th© vertical distribution of animal plankton In the Sea of Japan off San'in district in th© summer of 1953. Pub. 2©to Mar, Biol. Lab. 38 81-74.

Giesbreeht, f,, 1892. Syatemetik and Fuanistik der pelagis- chen Copepoden des Golfes von Seapel und der angren- zenden Meerabsenltts, Fuana und Flora des Golfes von leap©!, monog. 19, Berlin.

Hardy, A.C, and E.R. Gunther, 1935, fhe plankton of the South Georgia whaling grounds and adjacent water 1926-7. Disc. Rep, no, 11.

Jesperson, P. and F.S. Hussel, 1952, (Directors). Flehea d" identification du zooplankton* Cons, Expl, Mer», not, 1*17, 30-49.

Johnson, 1»W,, 1934a. The life.history of th© copepod Tortanus discaudatus (Thompson and Scott). Biol, Bull. #MM-20C Johnson, M.S., 1934b. The developmental stages of the ccpepod ggilabldocera amphitrites Memurrioh, Biol, mil. 67*466- 483.' Lebour, M.V., 1916, Stages la the life history of Galanua flnaaarchloua (Gunnarus) experimentally reared by Ir, L.R. Grawshay In th® Plymouth Laboratory, Journ. Mar. Biol. Assn. 11il-

Sloholls, A*G., 1933. The biology of Galanua flnmarohjoue* I. Reproduction and seasonal distribution in the Clyde Sea area during 1932. Journ. Mar.Biol,Assn. 19t 85*101. Sara, G.O., 1903. The Crustacea of Norway. Vol, IV. Bergen Museum. Sverdrup, H.U., Johnson and R.H. Fleming, 1952. The oceans. Prentice-Hall inc., Hew York*

U ssing, H.H., 1938. The Biology of some important plankton animals in the fiords of East Greenland, Medd, oWnland, Bd. 10081-108. Wilson, C.B,, 1950* Oopepoda gathered by the United States steamer "Albatross" from 1887 to 1909, chiefly in th© Pacific Ocean* U.S.Iat.Mus.Bull. 100, vol, 14, pt. 4. Afturaoc

S - rare

THE OCCURRENCE AND RELATIVE ABUNDANCE OF TEE COPSPOD SPECIES II ALL THE PLANKTON SAMPLES

Locality Hecate st rait

64 65 70 103 Station 68 69 104 102 101 100

44 Saul Depth 23 1 22 1 1 6 18 1 36 75 69 27 91 u.e Surftot Temp/c 14.8 14.5 12.6

J Copepods / 0. Helgoland!ea 0 F C P P P F C P p R C C C c 0 f~ c ' 0 P. mfnutu© F " c" 9'1 "¥'A""" 0 C 0 A. clausi ft R R F c c A, p ? "o"T'Ttl a F T C longer imls "inr""«T~¥ P~ 0 C. racmurrlchl C R IR s p T. disTauda'tus , '0 "'"'"L C " f ' R R R 0. nor vesica s R eon If era ^—_—« — E. hlrundoidos" : —.——~~——•if — P. Darvus R 1. rosea _ , , ———~ .—-« ———— ii • C. affinia'" 01 C,' f Inmarchicua ' R fi• Si C P M. lucens ' w E. nmohitrltea Ri 0. pluwifera .. . . . —.—.—— ~ A. araatus ; „,,• —; — 1» hungll — — —. — slafilFl _ —

C. erlatatua" ,....-....,„.rt „ ,, ,„,, - — • 6. tonsua . , ; ——• **— S. minor f 1. japohiaa . , , - ~—,—>—.—• •— 0. oolumb-Ia© . — —— —.—••———

Pleuromamma ~—; - _ Betordrhabdua .. ——. - „,„,.,,..,. » . Saetanus , , ,——.—.—,—— ———•—-— C« aoulcbrnla ,,. ,—,—~— M. lonft® . ————.———, , . —— Rhlncalanus ,„„,,..... „— , -—,—:—:————-•— Chiridlus S. aubdeptata ,—-—• — —*— f> R * rare . few 0 - common A - abundant -> * all stages to e - eggs 1 - Immature only TABES I (continued)

Locality Dixon &ntrance

99 72 73 91 92 90 97 81 88 96 Station 71 90

Haul Depth 127 1 91 47 54 5 15 3 27 8 35 65 »i-5 i o 42 3 45 ______• — "'H t9—— 13.4 Surface Temp. 12.7 12.0 124 11.9

Cooepods: F C C C C C OA 0. helgolandloa / P Fl R ce_o_ t~ F F* C C C C rnlnutus 0 C X 0CCA X clausl 1x~x A. G -f—i!—mr A. lonserlrnla C Fl T xx~x X A C. racmurriehiF" T—rr— FTT TT TTX TT Tl IT He Rc "T» discauoTatua e X X X~l F —TR 1.' nb'rve^lca" 0. xx— hiruHd*oTdeeonlfera s TTX "M. rosea C. affinlt "I J ^^ 'F£hS7cM^u?"^?* T x—c~x~""xr M. lucens X X E0.. plumifaramphitritga i R. X A. armatus EK. hslSilau V T *UT~cri status C. tonsus S. rainor X "C~. co ponaea .. Pleuromammlum'biaa e raBeterorhabdugm i. j "» .' " 1 f. 'g , Gaetanua C. aouicornis M. long>na

eggs R P- C - abundant e - I - Immature only all stage _ rare few - common A to TABLE I (continued)

Locality" Station —TTZ US ITS——JTW~ TO TSs TiT f>ep'tn" ''I4»'8 TBTo- TBTo" Surface Temp* 1S»1 Copepods* urnr F O c s A G .helRolandlca C 0R~ X X~ X X XT F.minutus X Z A.claus, l Hmra'~~~^ X X X A longe Ii F" .mcmurrlcM "X "IT O X X X X 7 X ¥ .di s cauda' tu a" X X X X M.norvegica"1'"'" "0 F X X O.conTfera X E.hiruDdQidea

Gaetanui" tr.aeuieornla M.longa Rhincalanus Chiridius S«aubdentata R - rare F - few C - common A - abundant e - eggs 1 - immature only - - all stages to He si it 38 o 0 • I n a 1 ill IP o i r 1 jctjc If u a 1 4 erf SHI