"Science, Faculty of"@en . "Zoology, Department of"@en . "DSpace"@en . "UBCV"@en . "Legare, Joseph Eugene Henri"@en . "2012-03-21T18:45:40Z"@en . "1956"@en . "Master of Arts - MA"@en . "University of British Columbia"@en . "A study of plankton communities in the Strait of Georgia was\r\nundertaken in order to determine qualitatively and quantitatively the\r\ndistribution in time and space of both zooplankton and phytoplankton.\r\nIn order to gain some picture of the seasonal, variations in the\r\nplankton communities two cruises were made in the Strait, one in June,\r\n1955, and the other in November 1955. 165 plankton collections were\r\ntaken. A complete count of zooplankton organisms was made in 5cc. of\r\neach sample and the number of diatoms cells per liter was tabulated.\r\nCopepods and diatoms were analysed to species; other groups to class\r\nor genera. Surface temperatures were taken. The physical and chemical\r\ndata, used to account for the biological distributions were obtained\r\nlargely from oceanographic data already available for the area.\r\nThe correlation of these data have resulted in a number of\r\nconclusions concerning the distribution of plankton in the Strait of\r\nGeorgia. The chief factor affecting the general distribution of plankton\r\nin the Strait of Georgia is the salinity gradient. The inflow of fresh\r\nwater from the Fraser River forms zones of varying properties, and leads\r\nto the development of different plankton communities. The extent to which\r\nphysical and chemical factors may determine the presence or absence of\r\ncertain organisms from the zones described is discussed."@en . "https://circle.library.ubc.ca/rest/handle/2429/41665?expand=metadata"@en . "THE QUALITATIVE AND QUANTITATIVE DISTRIBUTION OF P L A N K T O N IN T H E S T R A I T O F G E O R G I A I N R E L A T I O I TO C E R T A I N OCMNOGaRAPHIC FACTORS by JOSEPH E U G E N E H E N R I U S G A R B B.SC, LAVAL UNIVERSIW, 1953 A T H E S I S SUBMITTED I N P A R T I A L FULFILL16NT O F T H E R E Q U I R E M E N T S F O E T H E D E G R E E O F M A S T E R O F A R T S ia tho D E P A R T M E N T O F ZOOLOGY We accept this thesis as confonaing to the standard required frea candidates for the degree of M A S T E R O F A R T S Members of th\u00C2\u00AE Department of Zoology T H E UNIVERSITI O F BRITISH GOXWIA A p r i l , 1956 I P A study of plankton communities in th\u00C2\u00A9 Strait of Georgia was undertaken in order to determine qualitatively and quantitatively the distribution in time aad space of both aooplankton and phytoplankton. In order to gain some picture of the seasonal, variations in the plankton communities two cruises wer\u00C2\u00AE made in the Strait* one in June, 1955* and the other in Mov@*@r* 1955 \u00E2\u0080\u00A2 165 plankton collections were taken* A complete count of zooplankton organisms was made in 5cc\u00E2\u0080\u00A2 of \u00C2\u00A9ash sample and the number of diatoms cells >per liter was tabulated. Copepods and diatoms were analysed to speciesj other groups to class or genera* Surface temperatures were taken* the physical and chemical data, used to account for th\u00C2\u00A9 biological distributions wer\u00C2\u00A9 obtained7 largely from ooeanographic data already available for the area. Th\u00C2\u00A9 correlation of these data have resulted in a number of conclusions concerning the distribution of plankton in the Strait of Georgia. The \u00C2\u00A9hief factor affecting th\u00C2\u00A9 general distribution of plankton in the Strait of Georgia is the salinity gradient. The inflow of fresh water from the Fraser River forms zones of varying properties, and leads to the development of different plankton caamunities. The extent to which physical and chemical factors may determine the presence or absence of certain organisms from the acnes described is discussed* - i i i -mm OF Qowwfg PA01 i . imoDUcnoH i I I . DXS&JBtraSGtf QT PHYSICAL A \u00C2\u00BB CHEMICAL PlOmTIES O F THE wAms I N T H S snux? OF G E O S G I A 5 a* Salinity 5 b. Teiaperataro . . . . . . . . . . . . . . . . . 7 III. MflSIALS AM) METHODS 11 a. Area covered . . * \u00E2\u0080\u00A2 \u00E2\u0080\u00A2 \u00E2\u0080\u00A2 . \u00E2\u0080\u00A2 \u00E2\u0080\u00A2 \u00E2\u0080\u00A2 \u00E2\u0080\u00A2 \u00E2\u0080\u00A2 II b. Sampling methods . . . . . . . . . . . . . . . 16 1* Vertical hauls . . . . . . . . . . 16 2. Hardy Recorder tows 17 e. Laboratory methods 18 I V . RE3ULTS \u00E2\u0080\u00A2 1 9 Composition of the plankton 19 1. Zeoplankton taken in the suramer cruise, June 8-16, 1955 . . . . . . 19 2. Phyteplanktori taken in th\u00C2\u00A9 master cruise, Jane 3-16, 1955 . . . . . . 23 3\u00C2\u00BB Zooplaakton and phytoplaakton taken in the f a l l \u00C2\u00A9raise, November 7-ll\u00C2\u00BB 1955 \u00E2\u0080\u00A2 * \u00E2\u0080\u00A2 28 ?. DISCUSSION . . . . . . . . . . . . 32 a. Abundance \u00C2\u00A9f plankton in the Strait of Georgia, 32 1* Abundance of gooplanktou in the sower \u00C2\u00A9raise* Jvm 8-16, 1955 \u00C2\u00BB \u00E2\u0080\u00A2 |2 2 . Abundance of pliyf^plankten in the susener cruise, Jtsae 0-16, 1955 . . . 37 3\u00C2\u00AB Abund&ne\u00C2\u00A9 of zooplankton and phyto-plaiikfcoa in the f a l l cruise* l\u00C2\u00A9ir\u00C2\u00A9a3\u00C2\u00BBr 7~1\u00C2\u00A9# 1955 . . . . . . . . 42 b. Distribution of the plankton 46 1 . Vertical distribution \u00E2\u0080\u00A2 \u00E2\u0080\u00A2 \u00E2\u0080\u00A2 \u00E2\u0080\u00A2 \u00E2\u0080\u00A2 \u00E2\u0080\u00A2 \u00E2\u0080\u00A2 46 2. Horizontal distribution at constant depth 47 e. Some charaeteriatics of the nest important groups . . . . . . . . . . . . \u00E2\u0080\u00A2 . 53 1. Copepods . . . . . . . . . . . . . 53 -\u00C2\u00BB i v -TABfiB Of OQWaKft (e\u00C2\u00ABmelud\u00C2\u00A9d) PAGE PseudoealaRua iKinutog 54 Aoartia * \u00E2\u0080\u00A2 * \u00E2\u0080\u00A2 * \u00E2\u0080\u00A2 \u00C2\u00AB # \u00E2\u0080\u00A2 \u00E2\u0080\u00A2 \u00E2\u0080\u00A2 \u00E2\u0080\u00A2 \u00C2\u00BB \u00E2\u0080\u00A2 55 Qjthcam \u00E2\u0080\u00A2 \u00E2\u0080\u00A2 . . \u00C2\u00BB . . \u00C2\u00BB . . . . \u00C2\u00BB \u00E2\u0080\u00A2 5\u00C2\u00AE Calamas \u00C2\u00AB \u00C2\u00AB \u00C2\u00BB * \u00C2\u00AB \u00C2\u00BB * \u00C2\u00AB \u00E2\u0080\u00A2 \u00E2\u0080\u00A2 \u00C2\u00AB \u00C2\u00AB \u00C2\u00AB \u00E2\u0080\u00A2 * 59 Metrldla \u00E2\u0080\u00A2 \u00E2\u0080\u00A2 \u00E2\u0080\u00A2 \u00C2\u00BB \u00C2\u00AB \u00C2\u00AB \u00E2\u0080\u00A2 \u00C2\u00BB * \u00E2\u0080\u00A2 \u00E2\u0080\u00A2 \u00C2\u00BB \u00E2\u0080\u00A2 60 laijalaaai\u00C2\u00AE Iwrwdi. . . . . . . . . . 61 C@ntropag@8 moimu'rlalxi . . . . . . 62 Other species \u00C2\u00A9f restricted distributieii Offi^auga: eonifera \u00E2\u0080\u00A2 \u00E2\u0080\u00A2 \u00E2\u0080\u00A2 \u00E2\u0080\u00A2 \u00E2\u0080\u00A2 \u00E2\u0080\u00A2 \u00E2\u0080\u00A2 \u00E2\u0080\u00A2 \u00E2\u0080\u00A2 64 800^^.1^.6\u00C2\u00AE!!^' ifteai* . . \u00C2\u00AB \u00C2\u00AB \u00E2\u0080\u00A2 64 Microcalanus pusHliaa . * \u00E2\u0080\u00A2 \u00E2\u0080\u00A2 \u00E2\u0080\u00A2 \u00E2\u0080\u00A2 65 Euehaeta .laponica . . . . . . . . 65 Faraealanus parrus . . . . . . . 66 \u00C2\u00A9^r^ an^ jg discaudatus . . . . . . 66 Epllabldoeera aiaphitrites . . . \u00E2\u0080\u00A2 66 . m^rnm and ghirMitts tenuispinuB . . 66 - 2. Appendicularlsns \u00C2\u00BB\u00C2\u00AB\u00E2\u0080\u00A2 \u00C2\u00AB \u00E2\u0080\u00A2 \u00C2\u00BB \u00C2\u00AB \u00C2\u00BB \u00E2\u0080\u00A2 * 67 $\u00E2\u0080\u00A2 Euphausids \u00E2\u0080\u00A2 \u00E2\u0080\u00A2 \u00E2\u0080\u00A2 \u00E2\u0080\u00A2 \u00E2\u0080\u00A2 69 4* Cliaetogtiaths . . \u00E2\u0080\u00A2 \u00E2\u0080\u00A2 \u00E2\u0080\u00A2 \u00E2\u0080\u00A2 \u00C2\u00BB . . \u00E2\u0080\u00A2 \u00E2\u0080\u00A2 . 74 5 \u00C2\u00BB Amphlpods . . * . . . . . . * . . \u00C2\u00AB 75 6. Gastropods \u00E2\u0080\u00A2 \u00E2\u0080\u00A2 \u00E2\u0080\u00A2 \u00E2\u0080\u00A2 \u00E2\u0080\u00A2 \u00E2\u0080\u00A2 \u00E2\u0080\u00A2 \u00E2\u0080\u00A2 76 ?. Ostracods and Cladocerans . * . # \u00E2\u0080\u00A2 77 #\u00E2\u0080\u00A2 Larvae 79 9\u00C2\u00BB OistosB\u00C2\u00AE \u00C2\u00BB \u00E2\u0080\u00A2 \u00C2\u00AB \u00E2\u0080\u00A2 \u00E2\u0080\u00A2 \u00E2\u0080\u00A2 \u00E2\u0080\u00A2 \u00E2\u0080\u00A2 \u00E2\u0080\u00A2 \u00E2\u0080\u00A2 \u00E2\u0080\u00A2 \u00E2\u0080\u00A2 \u00E2\u0080\u00A2 \u00E2\u0080\u00A2 S3 Skeletoneiaa . . . . . . . . . . . 81 Thalaaaioaira 81 \u00C2\u00A7h\u00C2\u00AE^mm\u00C2\u00AEft \u00E2\u0080\u00A2 . \u00C2\u00BB \u00E2\u0080\u00A2 \u00E2\u0080\u00A2 * \u00C2\u00BB \u00E2\u0080\u00A2 * # # 84 .MitgasMa 84 Khjgoaelenia . . . . . . . . . . 86 Biddulphia \u00C2\u00AB.*#*\u00C2\u00BB\u00E2\u0080\u00A2\u00C2\u00BB**\u00E2\u0080\u00A2\u00C2\u00BB 87 thalassimem . . . . . . . . . . V I . CC*ICUJ3XGMS . . . . f2 V I I . nfSfwcis . . . . . . . . . . . . . . . . . . . . . . . . 96 i*l^ y .PJT \u00E2\u0080\u00A2.^ '^^ ffiSS fwm PA\u00C2\u00AE 1. Strait of Georgia showing sections aad\u00C2\u00A9 with the Hardy Recorder * . . . . 2 a. Seasonal, variations in Fraser River discharge at Hope, B.O.* 1950 (after Waldletatk, 1952) 6 3. Surface temperatures, June 8 - 16, 1955 . . . . . . . . . & 4. Surface temperatures, November 7 - 11, 1955 10 5. Location of Stations, June 8 - 16, 1955 . . . . . . . . . 12 6. location \u00C2\u00A9f Statical* Novesaber 7 - 11, 1955 \u00C2\u00BB \u00E2\u0080\u00A2 13 7. Diagram of plankton net used in the survey . . . . . . . . 14 0. Diagram of Hardy Recorder in sectional view (after Hardy, 1939) . . . . . . . . . . . . . . 15 f. Zooplaaktm abundance from earfaoe to depths \u00C2\u00A9f 10, 20* and 50 asters, June 8 - 16, 1955 33 10. Fhytoplanktw abun&aae\u00C2\u00AE from surfaee t\u00C2\u00A9 depths \u00C2\u00A9f 10, 20* and 50 meters* June S - 16, 1955 \u00E2\u0080\u00A2 39 11. Salinity at two yard\u00C2\u00AE depth in the Strait of Georgia t r m synoptic sunrsy* June 1950 (after Wsldiotek, 1952) . . 40 12. 2\u00C2\u00A9oplankt\u00C2\u00AB abundanee trm swfae\u00C2\u00A9 to depths of 10, 20* and 50 asters, November 7 *- 10, 1955 45 13* Histograss showing the \u00C2\u00A9oeurrenee of \u00C2\u00A9opepeds at different depths, June S - 16, 1955 . 48 14* Histograms showing th\u00C2\u00A9 variations of g@eplankt\u00C2\u00A9n and phytoplanktm at constant depths* June S - 16* 1955 * \u00E2\u0080\u00A2 \u00E2\u0080\u00A2 50 - id LI3T OF FIGURES (concluded) FIGURE PAGE 15* Histograms showing the variations of aooplankte n at constant depths, November 7 - 10, 1955 52 16. NuRfeewof Aeartia l,m\u00C2\u00A3bM\u00C2\u00AE&9 found in the upper 10 aieters (a) and 20 asters (b) plotted against surfaoe temperatures, June 8 - 16, 1955 * * * * 57 17* Numbers of Qilcopleura epp.found in the upper 10 meters plotted against surface temperatures, June 8 - 16, 1955* \u00E2\u0080\u00A2 \u00E2\u0080\u00A2 63 10. Abundance of Jj^tpneata, f^tatuaat 10 feet, June a - 16, 1955 32 19. Abundance af S&Q&filftf4*ft @pp* at 10 feet, June a - 16, 1955 . . . * S3 20. Abundant of Ohaetoaeros @pg. at 10 feet, June & - 16, 1955 55 21. Percentage distribution of the four most predominant phyto-plankt\u00C2\u00ABa\u00C2\u00BB geaera along the Hardy Resold er cross-sections, \u00E2\u0080\u00A2tee & - 16, 1955 89 22. total phytopLanlcton abundance at 10 feet, June $ - 16, 1955 90 - v l l -LIST OF TABUS TA\u00C2\u00A7X$ FAGE I. Percentages, by numbers, of \u00C2\u00A9even constituents of th\u00C2\u00A9 aooplankton, June $ - lo, 1955 24 II* Estimated numbers of zooplankton and volumes of phyto-plankton collected, June 8 - 16, 1955 \u00E2\u0080\u00A2 34 III. Estimated numbers of zooplanktea and volumes of phyto-plankbon oolleeted, Noves&er 7 - H\u00C2\u00BB 1955 43 If. Averago aontaly distribution of Aoart&a IcistgireB^s la 1927 - 192* and 1920 - If29 (after Johnson, 1932). . . . . 56 7. Murabers of juvenile and adult SentropMos y\u00C2\u00BBrrlehl taken at I\u00C2\u00A9-\u00C2\u00A9, 20-0, 50-0* 100-0* aad 150*0 meters, June 8 - 16* 1955 \u00E2\u0080\u00A2 \u00E2\u0080\u00A2 63 \u00C2\u00A51. Larval stages* by atatoera* of eaphaasids, June 8 * 16* 1955 71 VII. Concentrations of adult euphausids taken at different depths, based on a total count of the animals In each sample, Novenber 8-11* 1955 . . . . . . . . . . . . . . . 73 VIII. eoneentr&tions of adult chaetognaths, taken at different depths, based \u00C2\u00A9a a total count of the animals in each sasnple* lovsMber 8 - 11, 1?5S . . 75 IX. \u00C2\u00A9fflaeeatratiens of adult a^phlpods* t aten at different depths, based on a total count \u00C2\u00A9f the animals ia each 76 sawple, Mmmfaar $ - H# 1955 \u00C2\u00BB * * \u00C2\u00BB . . * . \u00C2\u00BB . . \u00E2\u0080\u00A2 . . . X. fertioal distribution of gastropod larvae and \u00C2\u00A9onoeatys-tions at each depth, June 3 - 16, 1955 # * \u00E2\u0080\u00A2 * 77 XI. Average nwsfcers of \u00C2\u00A9\u00C2\u00A9pepod, baraaele, and orab larva\u00C2\u00AE caught in moh haul, Jun\u00C2\u00AE # - 16, 1955 . . . . . . . . . . 79 - viii The writer wishes to express his sincere thanks to the following? Th\u00C2\u00A9 National Research Cornell for providing financial assistance during the period \u00C2\u00A9f this study in the form of a Suamer Supplement during th\u00C2\u00A9 susaaer of 1955 and a Bursary during the Academic Term 1955-56} to Dr\u00C2\u00AB B.F# Seagel, Assistant Professor in th\u00C2\u00A9 Bepartiaents of goolo^- and Botany, for suggesting the problem, for arranging the cruises, for assisting throughout the entire progress of the work and preparation of the manuscripts Dr. M. Waldichuk, for the use of extensive unpublished data on the physical and chemical oceanography of the Strait of Georgiaj Dr. J.P. fully for the as\u00C2\u00A9 of \u00C2\u00A9ceanographio equipTOnt) Drs. W.S. Hoar, J . Sanjean, C*G. Lindsey, and G.L. Piekard, for the use of special aicrosoopic and drafting equipment j th\u00C2\u00A9 master and mm of the C.N.A.7. \u00C2\u00ABIhk0li,, for their assistance and co-operationi and fellow students for their help and numerous suggestions throughout the year. The Strait of Georgia \u00C2\u00A9couples a position of considerable inter-est for the study of plankton because within its limits l t presents an unusual complexity of conditions which differ greatly from summer t\u00C2\u00A9 winter. In summer the fresh water from the Fraser River flows into the Strait and spreads over the surface in cloud-like distribution, mixing with the saline water to form a brackish upper layer which is well differentiated from the more saline, homogeneous waters under-neath. In winter the river discharge diminishes and most of the water in th\u00C2\u00A9 Strait reaches an homogeneous state. Th\u00C2\u00A9 Strait of Georgia itself is located between the British Columbia Mainland and Vancouver Island, and extends from Latitude 48* 50\u00E2\u0080\u00A2 fl. to Latitude 50\u00E2\u0080\u00A2 OO' N. (Fig. 1). It is 120 nautical miles lcng and l i nautical miles wide. It has an average area of 2000 square nautical miles and a maximum depth of 230 fathoms. The weather is generally similar over the entire area of the Strait. The precipitation is high in the fall and winter, and the summers are generally sunny and warm. Air temperatures seldom go below freezing. In winter they average 2* C and may go as high as 10\u00E2\u0080\u00A2 C- In summer they average 18\u00C2\u00AE C. In accordance with the complexity of conditions, the distribution of speeies Is intricate and their relative abundance fluctuates widely \u00C2\u00A3rm place t\u00C2\u00A9 place and from time to time. It has been already pointed out by Fraser (1918), that certain free-moving shore forms which occur constantly throughout the surface at Friday Harbor disappear from near the surface at Departure Bay early in sumer, making the question of migration a matter of importance. Cameron and Moune\u00C2\u00A9 (1922) found that some species exhibit a difference in morphological character and rate of growth which can. be traced to different physical and chemical conditions, and shewed that th\u00C2\u00A9 Fraser liver was responsible for most of the conditions peculiar to these waters. Lucas and Hutchinson (192?) cams to the conclusion that diatom optima exist where th\u00C2\u00A9 Fraser River water and th\u00C2\u00AE sea water are mixed. They suggested the contribution of the Fraser i s in the form of mineral salts containing nitrogen, phos-phorous, and silica. They also stressed the important tide-diatom re-lationship; north of the Fraser the optimum i s at the flow* south of the Fraser i t i s at the ebb. Hutchinson (1923) showed that the richness of the plankton flora was largely dependent on the Fraser as a source of siHea and also upon the conditions which conserve this material. Hutchinson, Lucas and MoPhail (1929) dealt with th\u00C2\u00A9 seasonal variations in the chemical and physical properties of the Strait of Georgia in re-lation to phytoplankton. Hutchinson and Lucas (1931) studied the extent of tha Fraser River's effect on temperature, salinity, currents and fish food. Again i t was found that the amount of phytoplankton is greatest at the regions of water mixing, fully and Bodlmead (1954) also discuss diatom distribution in terms of dissolved oxygen, pH and dissolved nutrients. They attribute the high concentrations of dissolved phos-phates to the intruding ocean waters, and the high concentrations of dissolved silicates to the Fraser River waters. They suggest that the supply Of dissolved nitrates i s the limiting factor in phytoplaaktoa growth. Some preliminary work has been carried out by Gampbell (1929) on the distribution of definite classes of marine organisms in the Strait of Georgia. In this thesis an attempt is made to evaluate qualitatively and quantitatively the organisms responsible for the abundance of both phytoplanktea and sooplankton and to assess the physical and ohemloal factors affecting their distribution. - 5 -P- D3y\u00C2\u00AB>3OTiqi OF PRT3;0AL AMD CHpiOAL PROPERTIES OF TIE WAfERS IN TIE STRAIT OF GEORGIA The range of salinities existing in the surface waters of th\u00C2\u00AE Strait of Georgia varies from 1 fU at the Fraser River estuary t\u00C2\u00A9 25 at the northern and southern extremities (Waldichuk, 1955)\u00E2\u0080\u00A2 The Fraser River discharge dominate\u00C2\u00AE the general oceanography. The fresh water flowing into the Strait from the River spreads over the surface, mixes with the saline water, and forms an upper, brackish silty layer re-ferred to as the \"upper zone\" (Tully and Dodimead, 1954)\u00E2\u0080\u00A2 Low salinity cells exist in the southern Strait, and consistent gradients of salin-ity appear where the low salinity surface water mixes with the higher salinity waters brought up to th\u00C2\u00A9 surface by tidal action. Surface salinities are lowest over the eastern portion of the Strait along the mainland. The greatest variations occur in the suwaer close to the mouth of the Fraser. This corresponds t\u00C2\u00A9 the peak discharge of fresh water (Fig. 2). This peak discharge is the result of snow and ice melting in the upper reaches of the River. Small rivers entering at ether points in the Strait contribute about 16% of the total fresh water* The upper sone ie about 30 feet deep at the mouth of the Fraser and deepens to 00 or 90 feet as i t fans out over the Strait (Waldlohuk, 1952). Isolated cells of water \u00C2\u00A9f varying properties ar\u00C2\u00AE found at th\u00C2\u00A9 surface and their position depends on the Fraser River discharge, the tidal cycle, and the wind velocity. - 6 -500 JAN. FEB. MAR. APR. MAY JUNE JULY AUG. SEPT. OCT. NOV. DEC. 1980 Fig.2. Seasonal variations in Fraser River discharge at Hope, B.C., 1950 (after Waldichuk, 1952). Below th\u00C2\u00A9 upper sone there la a layer of fairly homogeneous salin-ity, referred to as the \"lower zone\", and between the upper sons and the lower zona, there is a transition layer, referred to ae the \"boun-dary sone\" (Tally and Dodlaead, 1954) \u00E2\u0080\u00A2 This boundary zone is character-ised by a steep gradient of salinities* In November the upper sone of low salinity is confined to the vicinity of the Fraser and averages 4 meters in depth (Tully, 1954)\u00E2\u0080\u00A2 Ho distinct upper sone is traceable in the northern part of the Strait at this tiro because of the low runoff of the Fraser Elver* b. temperature Surface temperatures in the Strait of Georgia for June, 1955, are given In Figure 3\u00C2\u00BB The southern Strait exhibits the lowest temperature (12*4\u00C2\u00B0 C). This Is produced by tidal currents in the channels mixing \u00C2\u00A9old, deep water with th\u00C2\u00AE surface water (Waldichuk, 1953)* The surface water is \u00C2\u00A9old near the Fraser River estuary (12.8* C at Station 12) because the inflowing fresh water is colder than the water in the Strait. The highest temperature (15.8* C) is recorded off Gabriola Island. Generally surface temperatures are lower in the eastern portion of the Strait along the mainland and higher In the western portion of the Strait as a result of insolation. The surface gradient over the whole area was only 3 \u00C2\u00BB4* G in June, 1955\u00E2\u0080\u00A2 The depth of heating corresponds to the upper mm which is generally less than 10 rasters deep in summer (Tully and Dodiaead* 1954) * Below a depth of 60 meters ths waters are fairly stable throughout the year, with temperatures around 7* C The \"boundary layer\" is characterised by a steep gradient of temperatures. F i g . 3. Surface temperatures, June 8 - 16, 1955. . - 9 -Surfaee temperatures in Hovember (fig* 4) are fairly uniform over th\u00C2\u00A9 central part of th\u00C2\u00AE Strait. The northern waters, which are in the sone of minimal change, ar\u00C2\u00A9 a little warmer with a difference of temperature over the Strait of only 0.9* G (ranging froa C to 9*4* 0.) * fhe effect of th\u00C2\u00A9 Fraser liver is therefore less marked In November, loss of heat to th\u00C2\u00AE atmosphere takes place. B\u00C2\u00BB Movsmber strong winds mix the waters to great depths so that th\u00C2\u00A9 deep waters are warmed and an isothermal state is reached (Tully and Dodlaead, 1954) \u00E2\u0080\u00A2 - l i -m. MATERIALS AND METHODS The data presented are based on 165 plankton collections taken in the Strait of Georgia during two cruises - on\u00C2\u00AE in early summer, from June 0 to 16* 1955, and one in th\u00C2\u00AE f a l l , from November 7 to 11, 1955* The first cruise covered 30 stations distributed throughout the Strait from the San Juan Islands to the northern end of Texada Island* How-ever, as a result of bad weather conditions at the time of the f a l l cruise, i t was possible t\u00C2\u00A9 reoceupy only 26 of the 38 stations established on the earlier cruise. The stations occupied are distrib-uted between latitudes 48* 48\u00C2\u00BB \u00C2\u00BB - 49* 40\u00C2\u00BB N and longitudes 122* 50\u00C2\u00BB W -124* 45' W (Figs. 5 and 6). At a l l but three stations two vertical hauls* using a plankton net (Fig. 7)* were mad\u00C2\u00AE. Th\u00C2\u00AE first haul was always taken in one of three shallower depths (froa 10, 20* or 50 meters to the surface) to prevent contaminating the net with deeper plankton species and a deeper haul was taken through strata varying froa 50 to 250 meters to the surface. Surface temperatures were obtained at a l l stations at which plankton samples were taken. Compass bearings were taken at the start of each haul. Records \u00C2\u00A9f scale depth* wind valoeity, barometer readings and cloud coverage were kept* A few stations were omitted during the two cruises in order to give maximum coverage of the Strait. In addition to the vertical hauls, horizontal sampling was carried out with the Hardy Recorder (Fig. 8) during the first cruise. The ctojeet in using th\u00C2\u00AE Hardy Recorder was to determine th\u00C2\u00AE horizontal - 14 -OCEANOGRAPHIC CABLE b) ROPES ( 3/8\" diom.) RING (20\" diom.) MESH SIZE 25 XXX METAL CLIP PLANKTON JAR 500 cc. a) STRING WEIGHT 50 lbs. Fig.7. Diagram of plankton net used i n the survey. - 15--16 -changes in the major constituents of the plankton over the areas Investigated between the stations at which the vertical hauls were made* b\u00C2\u00BB Sampling Methods In order to obtain some indication of the concentration of plankton at different depths and to trace the vertical and horizontal boundaries of distribution of the main constituents of both phyto-plankton and sooplankton, a number of sampling methods were employed* To determine the vertical limits of distribution of th\u00C2\u00A9 main constituents a plankton net was used (Fig. 7). The net measures 20 inohes in diameter at the mouth, 60 inches in length, and 4 inches in diameter at the cod-end. A jar having a volume of 500 c c is held tightly at the small opening by a metal slip. A string (7a) joins the metal clip to a 50-pound lead weight to keep th\u00C2\u00AE net from turning in-side out when lowering. The weight i s suspended from the lower end of three ropes (7b) \u00E2\u0080\u00A2 These ropes, which pass alongside the net, are tied around the metal ring forming the mouth of the net, and are attached above the mouth of the net to the oceanographic cable. The net is made of bolting silk Ho. 25 xxx. fh\u00C2\u00A9 same net was used throughout both cruises. I' W i c a l Haulg the shipboard procedure followed upon reaching a station involved first reversing the engta\u00C2\u00AE to bring the vessel to a complete stop. Some leeward motion of the ship was encountered while the sampling w being carried on, but this minor drift was disregarded. 17 -AH stapling was performed from the starboard side of the after deck, fhe ship was provided with a powered winch and a meter block. fhe net was lowered slowly at & uniform speed and. upon reaching the desired depth i t was also retrieved at a slew* uniform speed. When the net reached the surface i t was lifted out of the water and while s t i l l suspended from the oceanographic boom i t was washed down with three or four buckets of sea water, fhe plankton jar was then detached and the sample was transferred to a glass jar. The organisms clogging the net were washed free with a wash-bottle. Some formalin at % concentration was then added to the sample and a label was placed in the jar* U,Pttlt9W***FJffi\u00C2\u00A54,s \u00C2\u00A3a\u00C2\u00A3tat& Stein PA^JWHf, WfflflW v*r\u00C2\u00AB .fWri^tt Lemraeraann Genyavaax sisinifera (Olapared\u00C2\u00AE aad Laehmann) Percentages, by numbers, of seven constituents of the aooplankton are given in fable I. In almost all samples copepods were the most abundant of all constituents* the appendiculazlans (O^kopleura spp.) were second in abundance* followed by euphausids, eggs* chaetognaths* gastropods an! amphipods* Next, but not included in this table, were the larval stages of barnacle, crab, ostrocods, cladocerans, hydro-medusa\u00C2\u00AE, annelids, polychaete larvae, fish larva\u00C2\u00A9 and other, less frequent forms* At a few stations there occurred large numbers o f other specific group\u00C2\u00AE, such as Siphonophores and Llttoriaa, but in each case these were local populations and did not contribute to any extent to the overall distribution. 2) Phytoplaalcfeon taken ia th\u00C2\u00AE stammer ends\u00C2\u00AE, June S - 1 6 , 1 9 5 5 * Forty-five speeies of diatoms were found. Th\u00C2\u00AE following list is not complete and in a few cases the identification to species is some-what uncertain. Some slight differences of opinion on the taxonomy \u00C2\u00A9f certain specie\u00C2\u00AE are found in th\u00C2\u00AE literatur\u00C2\u00A9 (draa and Angst, 1931 and @upp\u00C2\u00BB 1943) which render th\u00C2\u00AE identification of certain sp\u00C2\u00AEel#s, such as in the genus Chaetoceros, difficult. Nevertheless, i t is possible to compare the relative abundance of most species in tha area with th\u00C2\u00AE data available. TABUS 1 Percentages, by numbers* of seven constituents of the zooplankton, June 8 - 16, 1953. Stn\u00C2\u00BB No. Depth (a) Eggs $ Cope-r Gasiro-! pods * Anmhl\u00C2\u00AB\u00E2\u0080\u00A2\u00C2\u00BB O'haeto-gnaths % auslds * pods 16 I 1\u00C2\u00A9 12 45 36 1 1 1 . 1 50 15 68 12 1 1 2 10 7 30 46 - 1 1 4 2 80 20 48 20 3 3 4 10 10 20 58 - 1 2 k 100 10 61 17 4 *> 3 5 20 3 50 23 2 2 5 200 4 32 5 4 - 1 6 50 5 29 32 1 7 7 10 30 33 12 1 1 1 3 7 90 25 69 2 1 \u00E2\u0080\u0094 8 50 6 67 4 4 12 8 110 3 76 7 4 5 10 10 27 U 55 -10 150 XL 51 26 3 \u00E2\u0080\u0094 2 11 10 mm 69 12 - \u00E2\u0080\u009E 14 11 100 4 65 14 1 1 9 12 10 - 64 10 - 10 12 50 12 60 15 - _ 1 2 33 10 - 88 7 13 50 6 72 8 - 2 \u00E2\u0080\u009E 3 14 20 5 22 64 - - 1 2 14 aoo 3 63 24 3 1 2 11 10 5 27 58 I - 2 1 15 im 3 58 24 6 1 2 16 10 - 87 4 - 1 7 16 mo 80 4 3 1 9 17 20 5 79 6 1 3 3 1? 150 4 78 7 4 1 4 IS is \u00E2\u0080\u0094 59 8 1 1 1 22 18 150 5 73 2 12 \u00C2\u00AB. 3 19 50 3 69 1\u00C2\u00A9 - 1 5 1 19 200 4 77 2 Z 2 6 20 20 17 54 15 \u00C2\u00BB - 4 2\u00C2\u00A9 250 8 71 5 \". 2 2 - 4 25 TABLE I (continued) Mo. (\u00C2\u00BB) Oastro- Amphi-pods pods CSsto^T gnaths auslds 9 \u00E2\u0080\u0094 . ,\u00E2\u0080\u009E \u00E2\u0080\u00A2, 7> , , ,\u00E2\u0080\u009E 2 2L 11 8 - 1 13 3? - - * 6 23 5 1 2 3 1 - 1 a 2 - \u00E2\u0080\u00A2 *\u00C2\u00BB 13 \u00C2\u00BB \u00E2\u0080\u00A2\u00C2\u00BB - 2 9 1 1 1 3 8 \u00E2\u0080\u00A2 1 2 5 - \u00E2\u0080\u0094 1 2 4 3 1 5 5 2 - 1 6 3 2 I 12 5 1 1 3 2 1 2 2 1 3 1 - 3 1 1 12 *\u00C2\u00BB 1 1 4 1 - 1 27 1 3 1 4 1 8 1 4 3 \u00C2\u00AB 5 1 1 2 3 * 11 11 17 3 1 4 1 5 '11 - - 3 8 6 3 2 13 11 5 - 1 2 5 6 - \u00C2\u00AB\u00E2\u0080\u00A2> 2 2? 1 1 1 8 2 3 - 20 5 4 - - 5 2 5 - - 6 2 \u00E2\u0080\u0094 \u00E2\u0080\u0094 \u00E2\u0080\u0094 3 4 \u00C2\u00AB 6 5 2 3 1 12 2 9 27 5 5 \u00C2\u00AB - 10 4 5 9 f - 2 7 12 - 2 33 1 1 1 3 7 . 5 3 1 5 24 2 21 21 22 22 23 23 24 24 25 .25 25 25 25 26-26 27 27 28 28 2f 2f 30 30 31 31 32 32 33 33 34 34 35 36 3? 37 38 38 41 41 43 20 150 10 100 10 100 20 50 10 20 50 100 15\u00C2\u00A9 20 150 20 50 20 23\u00C2\u00A9 50 150 10 150 10 100 20 100 10 200 50 ^ 100 10 100 50 100 20 100 10 200 50 6 3 17 2 49 17 23 18 35 17 13' 7 8 1 2 1 7 4 3 9 2 2 9 3 9 4 1 1 10 2 7 4 5 8 38 82 81 94 82 55 # 71 74 73 71 23 56 26 The following diatoms were identified* A^terfonolla japonjoa Cleve iaoteriastram delieatigtam Cleve M^f>*J4 (Lyngbye) Brebisson and Godey !\u00E2\u0080\u00A2 iaSSiS Ehrsnberg B. lengieraris Qrevill\u00C2\u00AE CMhaetoo\u00C2\u00AEros afflnis Laud.r \u00C2\u00A3\u00C2\u00BB brevis Sohttt \u00C2\u00A3\u00E2\u0080\u00A2 soneaviaomis Mangin \u00C2\u00A3\u00E2\u0080\u00A2 oontrietus Gran \u00C2\u00A3\u00E2\u0080\u00A2 g^vo^utfg Castraoan\u00C2\u00A9 \u00C2\u00A3. etigvisettts ciev\u00C2\u00A9 \u00C2\u00A3 \u00E2\u0080\u00A2 \u00C2\u00BB M 3 1 \u00C2\u00BB Cleve I* d\u00C2\u00AB9QiPiens Gl@v\u00C2\u00AE \u00C2\u00A3\u00E2\u0080\u00A2 ^ Mww Ehr\u00C2\u00AEnb\u00C2\u00AErg \u00C2\u00A3\u00E2\u0080\u00A2 laoin\u00C2\u00AEstts Sehtttt \u00C2\u00A3* i g w w t e a i Gy^w C. radieans Schfttt I* Sieve \u00C2\u00A3\u00E2\u0080\u00A2 teres Cleve \u00C2\u00A3\u00E2\u0080\u00A2 vanbeareki Gran ABESlLteai Jteg&Ste Jensen .g^ einodisetis jaf^ri.o.us, Ehrenberg C. waileaij Gran and Angst ft^ff \u00C2\u00BB * i f t * ^ t t \u00C2\u00BB (West) Grunow 27 ffMHBrt* ftO^ W^ff. IHrenkerg Frai&laria eretonensis Kltton \u00C2\u00A3* \u00C2\u00BBt,rjatula lyngby\u00C2\u00A9 flaMifrtfrFft ffi&M (l#ngby\u00C2\u00A9) Ktttzing |^ Bfc\u00C2\u00ABeylind\u00C2\u00ABtUf da^ oua. Clove HiSSSIS .pwtf,M ^?osolenia semispina, aad Nffigschla sp. were also encountered. Out of fifty-two samples, only thirteen gave values of more than 1 cell per liter and the maximum frequency never exceeded 10 cells per liter. Mo proto-scans were seen in the plankton samples taken in November* -32-V* PI30US3IOM a. Abundance <*f jg^kton in the Strait of Gsorgla 1) Abundance of zooplankton in th\u00C2\u00A9 summer cruise. June 8 - 16, 1955\u00C2\u00AB To provide a basis for comparison \u00C2\u00A9f the total catch at any one locality, all quantities obtained from the 5 ce. samples quantitatively analysed wr\u00C2\u00A9 transformed into values based on a standard volume of one cubic meter. This was done by dividing the number of aooplankton per sample by th\u00C2\u00A9 volume of water filtered. Since no device was used to record the amount of water filtered, it is assumed that th\u00C2\u00AE net was fishing vertically and no spilling occurred. With this assumption the number of cubic meters of water strained at each depth was then calculated. This method of calculation cannot give a complete eval-uation of th\u00C2\u00AE aooplankton distribution with depth, but it points out with a reasonable degree of accuracy th\u00C2\u00AE areas of high, average, and low concentrations. Based on the quantitative \u00C2\u00A9valuation of the zooplankton obtained ia the above manner three centers of different concentrations (Fig. 9s Tabl\u00C2\u00AE II) can be recognized and associated with th\u00C2\u00A9 physical and chemical characteristics of the waters in the Strait of Georgia. A) an area of high concentration at Station\u00C2\u00AE 10, 11, 12, 1 3 , 15, 21, and 22, with warm surface temperatures (ranging from 13\u00C2\u00BB5^C to 14\u00C2\u00AB7^ C) and strong mixing \u00C2\u00A9f water masses. B) an area of intarmediate concentration at Stations 1 6 , 1 7 , 1 9 , 20, 23, 24, 25, and 32, with colder surface temperatures (ranging from 12 .B% to 13.7*0) and little mixing of water masses. F i g . 9. Zooplankton abundance from surface to depths of 10, 20, and 50 meters, June - 34 -II 1 St r fojj f i lllililllli^PliillllBgs I3 te 1 1 i i . . . . . . . . . . | . . . 2B 3* Se Ss 3E 35 SB \u00C2\u00BB * \u00C2\u00BB gi \u00C2\u00BB \u00C2\u00BB \u00C2\u00A5 h* k* 8* &\u00C2\u00A7* Ss ^B Ss 5* MN -S1 S\ U N U N * 8 ' * 8 \u00C2\u00A9 $ i i i i 4 i i i 5 s s - 35 -I te I f ||HiiH|H||\u00C2\u00A7lg|II|i|ipgi 9 ilBllllllIIilliiBBIlllilill a s \u00C2\u00BB a s a s s | \" ' | | \" | \" I'M I'\"-fe a I \u00C2\u00A7 a fe & h\" \u00C2\u00BB' \u00C2\u00BB \" R\u00C2\u00B0 R* \u00C2\u00BB \" J \" S \" \" 5\" 3\u00C2\u00B0 S S S S S 3 *S S *E S S S \u00C2\u00BB \u00E2\u0080\u00A2 \u00C2\u00BB \u00C2\u00AB \u00C2\u00AB \u00E2\u0080\u00A2 \u00C2\u00AB \u00C2\u00AB \u00C2\u00AB \u00E2\u0080\u00A2 * v TABLE H ( Stn. Io. Position latitude loagit' ado Sat\u00C2\u00AE Tine PST 2d 49\u00C2\u00B0 23\u00E2\u0080\u00A2 10* I 123* 54' 15\" \u00C2\u00A5 14 1718 28 n w 1728 29 49* 22\u00C2\u00BB 10\u00C2\u00AB I 124* 01' 30* I June 15 1538 29 a s 1548 3\u00C2\u00A9 49\u00C2\u00AE 26' 45\" I 123* 54' 15\" V June 14 1627 30 ft 8 1637 31 49* 19\u00E2\u0080\u00A2 45\" \u00C2\u00BB 123* 51* 15* 1 June 15 1653 31 \u00E2\u0080\u00A2 1701 32 49* 15\u00E2\u0080\u00A2 15* I 123* 49' 30s W 1751 32 a 1800 33 49* 23' 30\" I 124* 16' 00* w 0619 33 n \u00C2\u00BB 0629 34 49* 26\u00C2\u00AB 20* I 124* 23* 00\u00C2\u00AB w tl 0725 34 \u00C2\u00BB a 0738 35 49* 29' 30\u00C2\u00BB H 124\u00C2\u00B0 30* 15 s W H 0827 35 \u00C2\u00AB a 0835 36 49* 33\u00C2\u00AB 15\" * 124* 27\u00C2\u00AB 00\" w a 0913 36 \u00C2\u00AB a 0921 3? 49\u00C2\u00AE 36' CC\u00C2\u00BB S 124* 33' 45* \u00C2\u00A5 \u00C2\u00BB 1008 37 \u00C2\u00AB H m t 38 49* 40* 00\u00C2\u00AB 1 124* 45' oo\u00C2\u00BB w ff 1124 3B w a 1138 41 49* 15' 40\" X 123* 42\u00C2\u00AB 54* w June 8 2320 41 a 56\u00C2\u00BB \u00C2\u00AB * 1345 43 49*13' 54* 1 123* 50\u00C2\u00AB Juno 9 1430 ) Depth retrained 20 4.06 1054 20 23\u00C2\u00A9 46.69 165 5 50 10.15 \u00C2\u00A943 9286 150 15.48 344 88 10 2.03 1460 12 150 I5.4S 1147 2f 10 2.03 5282 2605 100 20*29 742 1009 20 4.06 4666 1246 100 20.29 1144 528 10 2.03 2456 2553 200 40.58 677 78 50 10.15 3^ 90 1305 150 15-48 2191 1661 20 4.06 11070 5592 100 20.29 3225 774 10 2.03 3360 44351 100 20.29 1320 594 50 10.15 3880 1328 100 20.2? 2195 538 20 4*06 5141 7650 100 20.29 3072 178f 10 2.03 2850 2293 200 40.58 890 313 50 10.15 722 777 1 ot 1 3? S) aa area of law concentration at Stations 18, 26, 27, 20, 29, 30, and 31, with still colder surface temperatures (ranging from 12.4*0 to 13.6*$) and little mixing of water masses. The catches mad\u00C2\u00AE in the tows between 50 \u00C2\u00AB\u00C2\u00AEt\u00C2\u00ABrs and the surfao\u00C2\u00AE were more characteristic of the Strait of Georgia because they included populations inhabiting both th\u00C2\u00AE Hupp\u00C2\u00AEr zone\" and th\u00C2\u00AE uppermost stratum of the homogeneous \"lower zone\". Th\u00C2\u00AE catches proved to be fairly uniform from station to station, as far as th\u00C2\u00AE predominant species wer\u00C2\u00AE concerned, and thus copepods were, in most cases, the most abundant animals. However, regional differences in the relative abundance of copepods, \u00C2\u00A9uphsusids, amphi-pods and ehaetognaths resulted in notable differences in th\u00C2\u00AE plankton population from station to station. In some instances, one or another species dominated. Thus, at Station IS, the oepcpod Calarms tonsus formed the bulk of the catch from 150-0 meters. Surface hauls at Stations 12, 13, 17, 35, 37, 38, yielded very large numbers of .If^ doca^anug minutua,. sp* was predominant at th\u00C2\u00AE surface at four stations (4, 6, 10, and 14) as were eggs at Station 10 in a haul froa 10-0 meters. 2) Abundance of phyt\u00C2\u00A9plankton in th\u00C2\u00A9 summer cruise, June & - 16, 1955* It 1\u00C2\u00AE impossible to stat\u00C2\u00A9 on th\u00C2\u00A9 basis of a survey lasting only two weeks whether the conditions encountered in June 1955, are typical for this period of the year. The 1st\u00C2\u00AE spring and relatively cold June of 1955 may have affected the abundance of diatoms and delayed the period -38-of peak abundance? according to von Hoff\u00C2\u00BBs Law a 10% rise in temperature increases the rate of metabolism 2 to 3 times* Campbell (1929) found that temperature changes and plankton occurrence are definitely correlated within the limits of 10*0 - 15 *0* Within these limits, at least, an increase in temperature is accompanied by an in-crease in plankton in th\u00C2\u00A9 Strait of Georgia. Although absolute abundance of diatoms during the period of this study i s only a measure of the standing crop i t is probably indicative of a fairly productive area (Fig. 10). The maximum number of diatom cells per liter (124,480) in the Strait of Georgia does not compare with 20,000,000 cells recorded in th\u00C2\u00AE 01yd\u00C2\u00A9 Sea in April 1927 (Marshall and Orr, 1927)\u00E2\u0080\u00A2 Comparison between th\u00C2\u00AE maximum count obtained in June 1955 (25A00\u00C2\u00BB000 vol.) and th\u00C2\u00AE maximum volume reported by Hutchinson and Lucas in July 30, 1927 (H0/l00,000 vol.) show that the values obtained on the latter date were roughly four times higher. This suggests that catches taken in June 1955 were preceding or following a period of greater abundance and that greater quantities could b\u00C2\u00AE expected from the area. Few diatoms were taken at Stations 13, 16, and 17 clos\u00C2\u00AE to the Fraser River estuary (Fig. 10). This region is characterized by a low saMaity (Fig. H) and a high turbidity. Th\u00C2\u00AE latt\u00C2\u00AEr greatly reduces th\u00C2\u00AE depth \u00C2\u00A9f the photic zone which in turn affects the growth of phyto-plankton. In th\u00C2\u00AE center of the Strait th\u00C2\u00AE standing crop ia June, 1955 was higher in the western portion than in the eastern portions only Station lit, located at the mouth of Vancouver Harbour, wh\u00C2\u00A9r\u00C2\u00A9 mor\u00C2\u00A9 F i g . 10. Phytoplankton abundance from surface to depths of } 0 , 20, and 50 meters, June 8 - 16, 1955. - 40 -F i g . 11. S a l i n i t y at two yards depth i n the S t r a i t of Georgia from synoptic survey, June 1950 (after Waldichuk, 1952). - 41 -extensive mixing is taking plaoe, showed a relatively high standing crop. Several authors (Hutchinson and Lucas 1931; Tully, 1932) Waldichuk, 1952} have observed a larger flow of Fraser water along the eastern portion of the Strait bringing lower salinities to the area. Temperatures are also colder in this region (Fig. 3). Th\u00C2\u00A9 salinity gradient is therefore one of the chief factors affecting the general abundance of phytoplankton in this central region of the Strait. The standing crop of the surface waters at Stations 35, 36, and 38 in the northern area was high (Table II). Tully (1932) found a decrease of phosphate concentration during the summer and low silicate values (1 mg/l. in July) in this area. This decrease in the chemical constituents ean be attributed to phytoplankton activity and sine\u00C2\u00AE the latter region i s located in the less turbulent part of the Strait (Tully, 1954) i t i s evident that depletion of silicates will limit phytoplankton growth. Tully (1932) suggests that other nutrients do aot reach concentrations low enough to limit the development of phyto-plankton. fhe highest standing crop appeared south of Point Roberts at Station \u00C2\u00A9. Hutchinson and Lucas (1932) and Waldichuk (1952) found that strong physical and chemical gradients existed in this region where fresh and salt water mixing occurs. Both fresh water and sea water masses contributed certain favourable factors for th\u00C2\u00AE rapid growth of the phytoplankton population. 42 -3) Abundance of aooplankton and phytoplanktoa in the f a l l cruise. November 7 - 10, 1955\u00E2\u0080\u00A2 Tb\u00C2\u00AE collection\u00C2\u00AE taken in November present a picture of th\u00C2\u00AE abundance of plankton in th\u00C2\u00AE central and northern regions \u00C2\u00A9f the Strait. Sine\u00C2\u00AE the data (Table III) wer\u00C2\u00AE taken only during th\u00C2\u00A9 day-light period they d\u00C2\u00A9 not give a true quantitative value, but only an approximation of th\u00C2\u00AE abundance of plankton i n November. te\u00C2\u00AEpt for a region of moderate concentration (Pig. 12) at th\u00C2\u00AE boundary of th\u00C2\u00AE eentral and southern regions of th\u00C2\u00AE Strait (Stations 7A, SA, 9A, 10A, and UA) and this \u00C2\u00A9 wid\u00C2\u00AEly separated localiti\u00C2\u00A9\u00C2\u00AE of moderate concentrations (Stations ISA, 19A, 20A, 30A, and $$k) th\u00C2\u00AE whole area of the Strait, covered in November, supported a uniformly low concen-tration \u00C2\u00A9f zooplankton. It has already be pointed out that th\u00C2\u00AE water reaches an almost heaogeneous state in the autumn with \u00C2\u00A9older tempe-ratures than in \u00C2\u00ABfune and a small salinity gradient. These two factor\u00C2\u00A9 are assumed to b\u00C2\u00AE Malting in November. Th\u00C2\u00AE region of moderate concentration corresponds to the 20a\u00C2\u00AE of greater fresh water and sea water admixture off Point Bobert\u00C2\u00AE wh\u00C2\u00AEr\u00C2\u00AE a high salinity gradient exists in November* Tha center of atoundanc\u00C2\u00AE for th\u00C2\u00AE \u00C2\u00A9opepod\u00C2\u00AE was i n ta\u00C2\u00AE 50-3 meter zon\u00C2\u00AE. Among th\u00C2\u00A9 \u00C2\u00A9opapeds, the juveniles of Oalanus ftoiarcMcas and Ps\u00C2\u00AEud#calanus \u00E2\u0080\u00A2tawfeaq wer\u00C2\u00AE predominant in 20-0 meter\u00C2\u00AE at Stations 7A, SA., 9A, 10A, HA, 15A, ISA, 19A, 20A, 2oA, 2SA, 3\u00C2\u00A9A\u00C2\u00BB SU\u00C2\u00BB 33A, 35A, and 36** while the adult\u00C2\u00AE of ga^ antt\u00C2\u00AE,, \u00C2\u00A3&mgMm*J&mm% lUMl* llStiS\" loaadrcaia wer\u00C2\u00AE predcrateant in 50-0 meters in th\u00C2\u00AE area. The copepod T A B U S H I Estimated srasfcers of zooplankton and volumes of phytoplankton collected Moveaber 7 - ID, 1955 Ho. Position Latitude Longitude Date Time psr Depth W W&ter^rained Zooplankton organisms Phytoplankt< cells per l i t e r 7A 48* 57' 15* I 123* 08\u00C2\u00AB 00* \u00C2\u00A5 Jtev.9 1610 10 2.03 4102 *1 7A II \u00C2\u00AB 1620 100 20.29 1028 * 1 SA 48* 55\u00E2\u0080\u00A2 51\" 1 123* 11\u00C2\u00BB 30\" W 1651 50 10.15 1148 <\u00E2\u0080\u00A2! SA w \u00C2\u00AB 1705 n o 22.33 660 *1 9a 48* 54' xm i 123* 16 \u00E2\u0080\u00A2 12* W 8 1324 20 4.06 603 1 9A \u00C2\u00BB n 1830 100 20.29 408 *1 10A 48\u00C2\u00B0 56t 06\" I 123* 18\u00C2\u00BB 16\" W a 1752 10 2.00 1460 <1 10A w 1804 150 30.45 408 <1 11A 49* 00\u00C2\u00AB 00\" i 123* 18\u00C2\u00BB 30\" w a 1510 10 2.03 1761 ^1 HA n 1518 100 20.29 641 3 Ihk 49* 03\u00C2\u00AB 43\" 1 123* 26\u00C2\u00AB 21\" W H 1400 20 4.06 313 <1 Ikk n 1415 200 40.58 203 1 15A 49* 021 00\u00C2\u00BB 1 123* 31* 45\" W n 1304 10 2.03 1136 ^1 154 t? 1315 150 30.45 437 and 'iMJidius tanuisDinxis live in th\u00C2\u00AE deeper layers (250-0 meters). Other groups of animals in the plankton also seem to follow a similar patten? ot distribution. Euphauaids as a group ar\u00C2\u00A9 represented by several larval stages, fhe aauplii and metanauplii wer\u00C2\u00AE generally abundant at 10-G meters, while th\u00C2\u00AE ealyptopis, furcilia and eyrtopia stage\u00C2\u00AE were found deeper. Juvenile Calanus were abundant at Stations 12 and 35 in the upper 20 motor\u00C2\u00AE. Qik\u00C2\u00AEpl\u00C2\u00AEura waa predominant at 10-0 meters, and was seldom found deeper. 2) Horizontal distribution at constant depth. Variations in abundance at constant depth for June S - 16, ar\u00C2\u00A9 - 4a -Depth in Ranges \u00C2\u00A9f Meters speeies X Q m Q ^ 2 5 ( M ) UiX>nona sp \u00E2\u0080\u00A2 Pssudccalanus minutus Acartia clausi A. longiremis Centropags\u00C2\u00AE mcmurrichi Tortams disoaudatus Microsetella rosea SurfaM Oneaea conif era hirundoides Paraealaaus parvus Coryoaeus affinia Calanus finaar@hi@us Maptesais sp* Calanus tonsus Epilabldooera amphitrltes DiosacouE spinasus Metridia longa Gaidius pungens Ascomyzon rubrum ^ Eurytemora johanseni forms Metridia luoens guebaeta japonica Mlerooalanus pusHlus Idya fureata Ceatregaptilus poreellus Ghirldius tenuispinu\u00C2\u00AE Scoleeitbrieella form\u00C2\u00AE minor A@tid\u00C2\u00AEus armatus Gandacia Columbia\u00C2\u00A9 iarpa@ti\u00C2\u00A9u\u00C2\u00AE unir\u00C2\u00AEmis Fig* 13* Histogram showing th\u00C2\u00AE occurrence of copepods at different depths, June 8 - 16, If55* Th\u00C2\u00AE heavy lin\u00C2\u00AEs indicate th\u00C2\u00AE zones of maximum abundance* 49 demonstrated by the histograms (Pig* 14). Th\u00C2\u00AE total sooplankton values are plotted in numbers per cubic meter. The shaded portion of the histograms represents the number of copepods in the catch and the narrow column to the right shows the volume of diatom cells per liter present in the same plankton sample. At 10-0 meters, a l l stations but two (Stations 7 and 30) have concentrations higher than 2000 animals per cubic meterj seven dis-play concentrations ranging from 2000 to 4000 animals (Stations 1, 2, 16, 1\u00C2\u00AE, 33* 36, and 41)I tbree more exhibit numbers of the order of 4O00 to 6000 animals (Stations 23, 25, and 3D, and seven have higher concentrations (Stations 4* 10, 11, 12, 13, 15, and 22). Aa inverse correlation exists at 13 out of 19 stations, between zooplankton quantities and diatom volumes. Where high blooms of diatoms occur, such as at Stations 10, IS, 33, 36, and 41, the number of animals is low. Station 12 has a very large number of animals and a low diatom population, low diatom concentration are also found at Stations 1, 2, 7, 11, 12, 13, 16, 23* 25, and 30. The situation i s somewhat different at 20-0 meters. Station\u00C2\u00AE 5* 26, 27, and 28 have concentrations lolow 2000 animals per cubic meterj Station 14 shows a value of 2800 animals per cubic meterj Stations 17, 20, 24, 25, 32, and 38* have values ranging from 4000 t\u00C2\u00AE 6000 animals* and Stations 21 and 35 have over 10,000 animals per cubic meter. An inverse correlation between sooplankton and phytoplanktoi i s apparent at Station 38 where diatoms predemiaate and mooplankton counts are low. The number of animals increases markedly at Station 35, n@ar by, where - 50 -1 4 T 10 i * i i i\u00C2\u00BB a i i a ma \u00C2\u00BB \u00C2\u00BB \u00C2\u00AB STATION N\u00C2\u00AB\u00C2\u00ABl[\u00C2\u00AB D | 9 T M 10 \u00E2\u0080\u00A2 IT to II H B \u00C2\u00BB !l STA T t OH aUMIC* DC ' I n 2 0 -i t is * i i \u00C2\u00BB r I I \u00C2\u00BB \u00C2\u00BB \u00C2\u00AB STATION NUMSC* DIPT* SOm 'jLiillltl J t 4 ll \u00C2\u00AB 2 2 ! ) ! i V S t \u00C2\u00BB M 5 7 Fig. 14. '\"Histograms shovdng the variations of zooplankton an! phytoplankton at constant depths, June 8 - 16, 1955--51-diatoms are loss numerous. At Stations 5* 17, 20, 24, 25, 26, 27, and 26, diatom volumes are law. Much higher counts are recorded at Stations 21 and 35 \u00E2\u0080\u00A2 At this depth copepods s t i l l form the major part of the catch, as shown at Stations 17, 25, 3 2 , 35, and 38* At \u00C2\u00A70*0 meters only Station 13 had a concentration exceeding 4000 animals per cubic meterj seven exceeded 2000 (Stations 1, 6, 12, 24, 25, 34, and 37) and five had less than 2000 animals per cubic meter (Stations S, 19, 27, 29, and 43)\u00E2\u0080\u00A2 Station 6, which exhibits th\u00C2\u00AE highest diatom concentration is located off Point Roberts, a region of relatively great turbulence. Moderate diatom concentrations also occur at Stations 12 and 29. Oikopleura sp. dominated th\u00C2\u00AE catch at Station 6, sggs and ouph-ausids wer\u00C2\u00AE found to predominate over copepods at Station 13. At a l l other stations copepods wer\u00C2\u00AE always th\u00C2\u00AE dominant group of animals at 50-0 meters. Greater depths d\u00C2\u00A9 not need to be considered in detail* It i s evident that quantities decrease very rapidly below 50 meters. A l l stations but five have concentrations below 2000 animals per cubic meter. Th\u00C2\u00AE other five stations (4, 21, 34, 35, and 37) have values ranging from 2000 to 4000 animals per cubic meter. Applying th\u00C2\u00AE sam\u00C2\u00AE analysis for the lighter November catehes, a similar type of distribution i s found (Fig. 15). At 10-0 meters a higher concentration of animals per cubic meter is found than at any other depths, and eepspods pradomiaat\u00C2\u00AE* At ZhO and 50-0 meters copepods ar\u00C2\u00A9 s t i l l the predominant form, but th\u00C2\u00AE relative concentrations of animals ar\u00C2\u00AE much smaller. B\u00C2\u00AElow 50 meters, - 52 -111 I g I M l*A 2QA 2 \u00C2\u00AB A 2*A JTA 2 I A S T A T I O N N U M B E R D E P T H 2 0 B 111 lilt TA K M HA OA ISA ZW 23* 25* \u00C2\u00BB * SA \u00C2\u00AB A 5AA S T A T I O N N'JM \u00E2\u0080\u00A2 [ \u00C2\u00BB OtPTM I 0 \u00C2\u00BB ? 1 1 S A 2 \u00C2\u00AB A 2SA 27A 2 % M \u00C2\u00BB STA S T A T I O N N U M B E R D E P T H M \u00C2\u00AB IIIJIJULLJ i i I B H \u00E2\u0080\u00A2 a M I \u00E2\u0080\u00A2 g Ji. IIA 22A 2JA S A S2A SB* M A STA O A ISA l \u00C2\u00BB A 2*A 2 S A JOA S4A HA ISA 5SA 28* 20A S T A T I O N N U M B E R -too* \u00E2\u0080\u0094 \u00E2\u0080\u00A2 O O \" \u00E2\u0080\u0094 \u00E2\u0080\u0094 \u00E2\u0080\u0094 ZOOm 2 5 0 \u00C2\u00BB 2 S 0 \u00C2\u00AB i F i g . 15. Histograms showing the v a r i a t i o n s of zooplankton at constant depths, November 7 - 10, 1955* - 53 -where mature Individuals aggregate, catches are very small, except for chaetognath\u00C2\u00AE, euphausids, and amphdpods. Diatom volumes are so small in Hovember that they do not appear on the histograms* 4* ilpbsraet^rls1tioBiiio^ the Most Important Sreufs. 1) Copepods* Copepods, either in the adult or larval stages, generally formed the main bulk of the aooplankton. there were more species and more Individuals present in June than in Hovember* Fraser (1918) also noted fewer numbers of copepods in the winter at Departure Bay* In the month of June, whenever copepods dominated the catch, tM!$r**L*m 9 s M t \u00C2\u00AB > 3#\u00C2\u00BBflW4\u00C2\u00BB> and Mhena sp* were mainly responsible* These three species together contributed 6556 of a l l cope-pods taken during the cruise. They were supplemented by Galanua sp. (15*). Metridia lon^a {%}> l^uoalanus bunfol (%)> Ifetridia lueens (3#)\u00C2\u00BB and Qentropages momurrichi (3$). A l l \u00C2\u00A9ther species contributed together only 2j$ of the total catch of copepods, in terms of numbers. Wherever juveniles were very abundant the same three doatnaafc a pedes were responsible* Calaaus sp. also contributed very high percentages of juveniles. Ia ths month of Hovember, fe^eea^us, fltifflfffoft* Wftm SP\" s n d Calanus finmarchlcus were the most numerous representatives of the goeplaiikton and formed 7$ of the total number of copepods. Next earns Metridia lueens (10$),,,g^Ieclthricella minor (2$), Merocalams pusillus (2$), Corycaeus affinis (2$), Acartia longiremis (2$), Para-ealams parvus (1$), and Buchaeta Japonioa (2$)j a l l other species 14 formed lees than % of the total catch. The following summarises the featured of the species regarded as significant. little attention is given here to the rarer species which must have some importance but contributed little to this study. A systematic treatment of the various species common in th\u00C2\u00AE British Columbia waters has been prepared by Campbell (1929) and most of the species studied hex* have been reported as characteristic of the area. J^ seud^ ca^ nug minutus,. The commonest species in June and November has a universal distribution in the Strait of Georgia. Jt is very abundant through-out the area and is found at all depths sampled. This suggests wide limits of survival for the species. It is one of the eewoaest species at Friday Harbor (Johnson, 1932), where i t is most abundant in the spring and autumn. Cameron (1955) mentions that P. minutus w so common everywhere in the Queen Charlotte Islands as to be useless as an indicator of water movements. The percentages of P. minutus forming the total catch ar\u00C2\u00AE fairly uniform for June aad Novembers 29$ of the total number in June, and 28$ in November. There is a definite degree of variation in th\u00C2\u00AE rati\u00C2\u00A9 of males, females and Juveniles forming the catch for different periods of the year* The males appear to be more abundant at the onset of breeding. For example, in June, from a catch of 7629 individuals, 12$ were males and 3$ females* Several females were egg-bearing and already 5<$ of the catch was made up of juveniles. Th\u00C2\u00AE number \u00C2\u00A9f males diainishes more - 55 ~ rapidly than th\u00C2\u00AE female\u00C2\u00AE after the breeding season. Thus i n November, 1955* 139\u00C2\u00A9 individuals were caught and th\u00C2\u00AE males amounted to only i$ of th\u00C2\u00AE catch, and th\u00C2\u00AE females to 25%. By this time breeding mast have been completed by this speeies, because no \u00C2\u00AEgg-bearing females could be found, furthexmer\u00C2\u00AE, th\u00C2\u00AE .Juveniles accounted for 1% of th\u00C2\u00A9 catch. Aoartia The genus Acartia i\u00C2\u00AE represented by two species in th\u00C2\u00AE Strait of Georgia: A. \m$&xwA\u00C2\u00AE and 4. clans*. Of th\u00C2\u00A9 two sp\u00C2\u00AEci\u00C2\u00AE\u00C2\u00BB\u00C2\u00BB Aeartla lon^ireinis i s by far the most abundant aad is characteristic of th\u00C2\u00AE whole Strait. It seems to be present at a l l seasons but shows wide Iluetuatienf in abundance. Thus 1# of th\u00C2\u00AE cepepeds taken in *?ua\u00C2\u00A9 was made up \u00C2\u00A9f A.. loajdresds, while th\u00C2\u00AE same species accounted for less than % of the catch i a Sorember. Wilson (1938) a@nti\u00C2\u00ABs that in 6\u00C2\u00A9EpHBy with A. clausi th\u00C2\u00AEs\u00C2\u00AE species f\u00C2\u00A9\u00C2\u00BB the chief constituents \u00C2\u00A9f the plankton @f Chesapeake lay. Blgelow and I^sli\u00C2\u00AE (1930) found k* l^mimmiM imimek in Monterey iay at station\u00C2\u00AE n\u00C2\u00AEar land and in comparatively shallow part\u00C2\u00AE et a few station\u00C2\u00A9 farther \u00C2\u00A9ut. At Friday Barber, Johnson (1932) \u00C2\u00BB@t\u00C2\u00AEs that 4. IM&M&M i s present at all . seasons but never in very large number\u00C2\u00AE. He gives th\u00C2\u00AE monthly distributim of XmtAxmOM in th\u00C2\u00AE year\u00C2\u00AE 19?7<-19t0, 1928-1929 (Table I f ) . - 56 -TABLE If Average monthly distribution of Acartia ImtdrmsL\u00C2\u00AE to 1927-192\u00C2\u00AE and 1928-1929 (after Johnson, 1932) A* IS JM^ r.eM.S Sept* Oct. Mm. Bee* Jan. Feb* March Apr. May June July Aug 1927 - 1928 * 8 17 4 1 3 4 5 9 9 10 2 1928 - 1929 * + 2 1 + + + \u00E2\u0080\u00A2 3 5 5 2 + pr< jsent (counts ai limal; 3 in 1 ml of sample) Th\u00C2\u00A9 abundance of Aeartia in June ( f i g . 16) corresponded to the peak of main increase i n the Fraser discharge, and since th\u00C2\u00A9 genus i s known to be euryhaline i t i s suggested that i n our region i t reaches it s peak abundance in summer, when low salinity warm water i s widely distributed. It i s distributed i n the upper 20 meters throughout th\u00C2\u00A9 Strait and reaches i t s maximum concent rations at Stations 13 and 21, which are located near the middle of the Strait opposite the Fraser River estuary. The waters become almost isottiermal i n Hovember at and th\u00C2\u00A9 upper aone of low salinity i s found only i n the vicinity of the Fraser i a the upper four meters (Tully and Sedimead, 1954). These physical conditions may account for the low quantities of both species of Acartia found i n Soveaber and for their aistribmtion in the deeper waters. During the breeding season, males and females share th\u00C2\u00A9 catch i n fairly uniform numbers, 25$ for the males, and 32$ for the females. When breeding is not taking place, females far outnumber the males. For example, i n Kovember when the temperatures wer\u00C2\u00AE too cold for the species - 57 -15 a. U J t3 i-I 2 J temp. L i 2 00 o o O. UJ 100 a. O o u i OJ 2 I 2 4 7 10 II 12 13 15 16 18 22 23 25 3 0 31 33 36 41 S T A T I O N N U M B E R F i g . 16 (a) Numbers of A c a r t i a longiremis found i n the upper 10 meters p l o t t e d against surface temp-eratures, June S - 16, 1955* -40C o Ui r-300 ' 2 0 0 o m > ~-in Q O 0. UI a. o o u i CD ( 0 0 5 14 17 2 0 2 4 2 5 2 6 27 2 8 32 35 3 8 S T A T I O N tf 'J M 8 E. H F i g . 16 (b) Numbers of A c a r t i a longiremis found i n the upper 20 meters p l o t t e d against surface temp-eratures, June 8 - 16, 1955* - 58-to reproduce (aiesbreeht, 1905 ex Cameron, 1955 gives U\u00C2\u00B0C as the minimum temperature for reproduction) but warm enough for survival, the female\u00C2\u00AE accounted for SQg of the catch, and th\u00C2\u00AE males for 1 $ . Thezfow fh\u00C2\u00A9 few copepodlds stage\u00C2\u00AE taken in the f a l l wer\u00C2\u00A9 in a late period of development, and showed many adult characteristics. Aeartla clausi Is euryhalJjie (Cameron, 1955) and should have been found in large numbers in June, but only scattered animals were found throughout the \"upper zone\". Ho reason, a\u00C2\u00AE yet, can account for this unusual distribution since Cameron (1955) reported th\u00C2\u00AE species a\u00C2\u00AE CCSSBOB in most areas in the Queen Charlotte Island\u00C2\u00AE. The possibility arise\u00C2\u00AE that th\u00C2\u00AE main concentration has been missed, or existed outside the areas investigated* \u00C2\u00A3. elausi i s rare in Nevest\u00C2\u00BB\u00C2\u00A9rj two specimen\u00C2\u00AE only have been found at Station 7A. Qithon^r This Mcrocopapod ha\u00C2\u00AE two representatives in the Strait \u00C2\u00A9f Oeergi&t t\u00C2\u00BB MM&MPm MMSSm* *\u00C2\u00BB analysis of several samples showed that \u00C2\u00A3. mMMMm ^ \u00C2\u00BBre eewon than \u00C2\u00A3. S&S&m* Th\u00C2\u00BB former was very abundant in the Strait in June when i t formed Ufa. ef th\u00C2\u00AE catch, but was s t i l l mere important in November, when i t formed 7.% of the catch. Sapaples Urn most stations were analysed only for total counts ef th\u00C2\u00A9 genus. At several stations, however, th\u00C2\u00A9 individuals were determined to specie\u00C2\u00AE and subdivided into sexes. The \u00C2\u00A9ample taken at Station 11 which i s a representative sample from 100-0 meters indicated th\u00C2\u00A9 following composition* 0. helgolandjea, 3 males, 66 females, and 4 Juvenile\u00C2\u00AE} 0. pluaifera, ? females. Every sample thus analysed produced a much greater ma*** of 0. .M\u00C2\u00A3$M$$M' - 59 -Olthona was found at a l l depths at a l l stations i n abundance but with a greater eonoeatratlen i n 50-20 meters. 0. helgolandiea which i s a l i t t o r a l species (Wilson, 1932), i s able to stand a wide rang\u00C2\u00A9 of physical, and chemical fluctuations of the waters. Its abundance suggests limits of survival beyond those found i n the Strait. On the other hand, p.. BJumifera> which i s a pelagic specie\u00C2\u00AE and chiefly tropical i n i t s distribution (Wilson, 1932), 1\u00C2\u00AE not able to achieve great abundance unless th\u00C2\u00AE waters have th\u00C2\u00AE optimum condition\u00C2\u00AE for th\u00C2\u00AE reproduction and development of th\u00C2\u00A9 species, loth a high temperature and salinity w i l l be required. Sine\u00C2\u00AE these conditions are \u00C2\u00AE\u00C2\u00A9Mea met i n the Strait \u00C2\u00A9f Georgia i a sunsaer, this aay account for the scarcity of the specie\u00C2\u00AE. When the temperature and salinity distributions ar\u00C2\u00A9 more homogeneous -in loveaber (see II) Oitheja MMmMm s t a i n s a higher eeneentratlea. h^l^olantlica i s also reported to be mm numerous i n the f a l l m the Pacific Coast at Friday Harbor (Johnson, lf|2) and at La Jolla (Esterly, 1928)* fhe pattern of distribution \u00C2\u00A9f this genu\u00C2\u00AE Is d i f f i c u l t to inter-pret from the available data. Because \u00C2\u00A9f tsputotaLe d i f f i c u l t i e s , the juvenile\u00C2\u00AE ef latest, m a n s^mn MmmMme^ m% identified with certainty to specie\u00C2\u00A9\u00E2\u0080\u00A2 two things atuft\u00C2\u00AE this genus iapertaats f i r s t , th\u00C2\u00AE presence of a larg\u00C2\u00A9 number of Juveniles, and second, th\u00C2\u00AE presence \u00C2\u00A9f a great swara of adults at Statiesa 18 (Fig. 5)\u00C2\u00BB Juveniles of QaXwaw aecomnted for Ut% of th\u00C2\u00AE eatch i a June aad 2|$ i n lovember, thus making i t mm of the meet significant owistituents mi the 8\u00C2\u00A9oplaofeten. This swarming - 6 0 -behaviour has been noted by several authors (Eaterly, 1905J Bigelow and Leslie, 193\u00C2\u00A9,* \u00E2\u0080\u00A2Johnson, 1932). It seems unusual that palanus ||nmarohloua. and Mm&lmm should breed in such numbers in the Strait since both are more pelagic than littoral i n distribution (Sars, 1903) and thus mast result from invasions from oceanic water through the Strait of Juan de Fusa. Whan more i s known about the distribution of each species in the Straits of Georgia and Juan de Fusa, some more apparent explanation may be evident. The adults of C. fi^marehicus were present at a l l but three stations and always in small numbers. A total of 13 males and ?0 f\u00C2\u00A9mate s were identified. C. tQnaus \u00C2\u00A9eourred in much larger numbers than C. f i n -raarchicus. A total of 909 individuals were identified as males. As for \u00C2\u00A3. erlstatus, only four Immature females were found in the Strait. la Hovember, only G. finmarchicuS; could be found, and i t was never present in abundance. The juveniles were spread throughout the area, but were most abundant at Stations fk and $k\u00C2\u00BB within the influence of the Fraser l i v e r . Metridia Metridia i s oa\u00C2\u00A9 of the most prominent genera among ths loss numerous copepods found in the Strait of Georgia* It i s represented by two apeelest M. jffltw* I* I&BS&i The species J\u00C2\u00A7* J ^ e \u00C2\u00BB l Is generally found with Manjg, |^arghjcu\u00C2\u00A3 in 100-0 meters hauls. The males, which are lea\u00C2\u00AE numerous than the females (193 males, 512 females) are found in shallower water than th\u00C2\u00AE females. In M0vember the males were found at a l l depths. Samples taken - 61 -at 20-0 meters and 10-0 meters yielded several adult specimens* The females, on the \u00C2\u00A9ther hand, were absent; from the upper 50 meters* Metridia has an extensive vertical migration. Esterly (1920) notes that they ar\u00C2\u00AE absent from the surface during the day, but are very abundant at the surfaee at night. The males of J\u00C2\u00A3. lueens, although less abundant than the females, are more generally distributed* Males were found at 31 stations in June, and females at 2 6 . Zn Movember males were taken at 24 stations, and females were found at 18. M. Jgoens is more numerous in the f a l l . Like aalanus fainmarehleus, i t has two breeding periods, on\u00C2\u00A9 i n the spring* and on\u00C2\u00A9 in the f a l l . The spring spawn must take place quite early in the season in the Strait, since in \u00C2\u00AE4d~June .only 16$ of the species were made up of young, whil\u00C2\u00AE were adults. Bxeept for two males of jetridja longa, a l l the Movember eaten of Metridia was mad\u00C2\u00AE up of Jf* lueens. Breeding of this species was taking place extensively in Movember. The catch i n November was as followsi 20 males, 33$ females, and 43$ young. There ar\u00C2\u00A9 wide seasonal fluctuations in th\u00C2\u00AE abundance of Metridia lonjffi. It was found in greater numbers than ]4. lucsns. in June, but was very rare l a Movember. It i s not known whether this i s a typical seasonal variation, gucalanus buneii Campbell (1929) mentions the presence of E. el^&gatus near Station 1 in the Strait of Georgia* As the main distinctive character of this species she claims the presence of 'a thorax with rounded ends to be diagnostic * I believe the specimens which she records belong to the 62 -species \u00C2\u00BBwiXwai\u00C2\u00BB bungli. Johnson (1932) and Davis (194\u00C2\u00B0) associate the above character with g. brogii and not with J|. elongatus* the latter bears points laterally on the posterior thoracic border. Bucalaaus bunidi was found during th\u00C2\u00A9 June \u00C2\u00A9ruise only, fhe catches were made up mostly of juveniles that live in the upper layers. Cameron (1955) did not find jg. bunM^ shallower thaa 50 \u00C2\u00BBet@rs in the Queen Charlotte Islands, but i t was found in greater numbers in 50-0 meters during this study. The adult males and females were generally found in the deep tows, but a good percentage were also distributed from 100*50 meters. Because of the uniformity of temperature and salinity of the lower son\u00C2\u00AE from 50 meter\u00C2\u00AE down, i t i s not surprising to find them in shallewer depths in the Strait than in the Queen Charlotte Islands* The greatest abundance of this species in Pacific waters i s recorded at 200 fathoms at Scripps (Beterly, 1928). The greatest number\u00C2\u00AE of E. bunsii wero caught at Stations 13 and 21, but the distribution was ubi smauem mJmPM Mm&^> .mm* Mm warn* tm*mw m$mM>m\u00C2\u00BB M\u00C2\u00A3m$g*m m^M^m* M & H Wm*m> I I M t e and a few others. The- speoiea not l i s t e d were represented by only a few scattered individual\u00C2\u00AE. 9mm mMm **\u00E2\u0080\u00A2 b e e n s h o w n i n the polar regions as well as i n the tropics (Wilson, 1932). It can therefore adapt i t s e l f to considerable fluctuations i n th\u00C2\u00AE environment. In the Queen Charlotte Island\u00C2\u00AE, Cameron ( 1 9 5 5 ) found that i t s presence was generally character-i s t i c i n areas of high surface temperature (above 1 3 * 5 ^ 2 ) and that i t inhabited the upper 75 meters. It i s distributed even deeper i n the Strait, of Georgia. It was found at a l l depths, but never i n abundance i n hauls taken shallower than 100 meters. It was common at Stations 5 , 1 4 , 2 f , and H at 100 meters or deeper. Ten males and 90 females were counted from 33 .stations i n June. A l l the males but \u00C2\u00A9no were found attached to the females, indicating that th\u00C2\u00A9 species breed\u00C2\u00A9 i n these latitudes. In November 2 5 female\u00C2\u00AE were noted at 16 differaat stations, but n^aales were found* $miWW*^ eniea was the largest of the \u00C2\u00A9epepod\u00C2\u00AE found i n the - 66 -Strait of Georgia. Im. June, males, females, and young ware always found deeper than 50 meters and were never In large numbers. They were present at half the stations. The males made 30$ of th\u00C2\u00AE catch, the females 10$, and the young 60$. 35. .japonica was present at a l l stations in Kovember and at four of them In fair awmbers. The young were found in shallow water and ths adults in deeper water. Hales formed 16$ of the total number, females 15$, and juveniles 69$. Faracalsnus parvus., fery small numbers were counted in June. The species was found at almost every station in lovember although never In abundance. It usually \u00C2\u00A9eourred near the surfaee ef th\u00C2\u00A9 water. The females always outnumbered the males (93$ against 7$). MM* ^eeaudatus. Is defined as a swsmer species by Wilson (1932). It was never found in any quantity during this study. It appear\u00C2\u00AE to be a \u00C2\u00A9uryhaline species* In the summer it was confined to the \"upper sone1* and in the autumn i t was restricted to the area adjacent to th\u00C2\u00AE fraser estuary* Only males (65$) aad young (35^ ) were found in November. MMM\u00C2\u00AE$m JSHMISl W tof recently in th\u00C2\u00AE summer, and always in small numbers. The catch was made up mostly of young (61$)* Th\u00C2\u00AE distribution could only b\u00C2\u00A9 estimated, due to low catches. On the basis of the distribution of those animals taken, the species Is assumed to congregate in the upper ao meters* In the .month of Uovember only one juvenile was seen in a l l the samples studied. M t e mom m d m^i^m smfadm b r i b e d as - 6 7 -Areti\u00C2\u00A9 speeies by Sars (1903)\u00E2\u0080\u00A2 They were very rare In Jane and occurred in the \"lower aone\". They were found In two-thirds of the hauls in November, but again in email numbers. All ether forms listed (see pp. 19, 20, 21) but not discussed were represented by only a few individuale and were too rare to enable drawing any \u00C2\u00A9meluslen\u00C2\u00AE from their distribution. 2) Appendioulsrians. The only appendicularia identified to genus was Qikogleura. Th\u00C2\u00AE widespread occurrence of these appendioularians (Fig. 17) is indicated in th\u00C2\u00AE June plankton* demonstrating the favourable conditions provided in th\u00C2\u00AE Strait of Georgia for the growth of these organism\u00C2\u00AE. Thus Oileenlsura was sufficiently abundant to be given th\u00C2\u00A9 second place in the list of abundant eooplankters. In the shallow.tews, appendioularians were represented only by larvae which were found at all station\u00C2\u00AE, some-times in numbers great enough to suggest centers of prediction. In such eases they far exceedulh\u00C2\u00A9 number of copeped\u00C2\u00AE as illustrated at Station\u00C2\u00AE 2, 4, 6 , 10, 14, 15, 22, and 41 (Table I). Johnson (1932) never found them in great abundance at Friday Harbor, but found them constantly present. Be also found a slight increase in June and October, when temperature\u00C2\u00AE, were apparently optima\u00C2\u00AE at 9*3*0 - I0*6*@. the larger numbers indicated above were found slightly below 12*13 in th\u00C2\u00AE Strait \u00C2\u00AB f Georgia* Bigelow (1930) feuwl 0. labradorenais for the most part in tes^ eratur\u00C2\u00AE\u00C2\u00AE below 12*6. According t\u00C2\u00A9 this author, \"sine\u00C2\u00AE it is most plentiful in temperatures of 12% - 13*0 at U Jolla, 12 *C may be set as its upper optimum limit in th\u00C2\u00AE northeastern Pacific\" It can thus - 68 -I 2 4 t K) II 12 13 19 16 8 22 23 2 5 30 31 33 3 6 41 STATION NUMBER Fig.1?. Numbers of Oikopleura spp. found in the upper 10 meters plotted against surface temperatures, June 8-16, 1955. V - 69 -b\u00C2\u00AE concluded that when temperatures of this order exist i n th\u00C2\u00A9 Strait, such as ware present i n June, 1955, appendieularians will reach a peak of abundance or an 'increase i n numbers. Campbell (1929) found them uniformly distributed at a l l depths i n the Strait of Seorgla. She reported also a greater frequency i n surfaee hauls (5-0 yards) at 7 ^ of th\u00C2\u00A9 stations, but she made no mention \u00C2\u00A9f heavy concentrations i n her summer catches* Th\u00C2\u00AE hauls made i n lovember yielded only small numbers \u00C2\u00A9f Oiko-pleura. Apparently their period of abundance does aot occur i n the autumn, or at least i n lovember, because only scattered adults were taken during this period. 3) luphausids. SuphausAds pass through a number of larval stages -in their growth from the eggs to the adult individuals. The literature i s somewhat confused concerning the number of stages* ivory author recognises the f i r s t six stages: naupHi I and 2, aetanauplii* and ealyptopig 1, 2, and 3* They are succeeded by various f u r c i i i a and eyrtopia stages. Buud (1932) has adopted a limited number \u00C2\u00A9f stage\u00C2\u00AE\u00C2\u00BB nauplil 1 and 2, metanauplii, \u00C2\u00A9alyptopis 1, 2, aad % early f u r c i i i a , Intermediate f u r c i i i a , late fureiHa, and a H eyrtopia.. the samples studied \u00C2\u00A9ontaiaed a l l the larval stages, but for the purpose of this discussion I have limited treatment to the following number of developmental stages! - 70 -1. nauplii and raetanauplli, 2. a H calyptepis \u00C2\u00AEtag\u00C2\u00A9s, 3. a l l f u r e i l i a stages, 4. a l l cyrtopia stag\u00C2\u00A9\u00C2\u00A9. Ho adults were taken at any of the station\u00C2\u00AE that yielded larvae. \u00E2\u0080\u00A2 fhe method of reproduction of this crustacean 1\u00C2\u00AE very similar to teat which occur\u00C2\u00AE i n the copepods. fhe eggs are shed i n the water, hut the growth i s slow and the animals do not reach sexual maturity u n t i l they ar\u00C2\u00AE two years old (Huud, 1932)\u00E2\u0080\u00A2 The euphsusids were present at every station i a at least s \u00C2\u00ABe stage of development i n June* Mauplii and metanauplii formed 9$ \u00C2\u00A9f the catch, calyptopie 4Q\u00C2\u00A3, f u r e i l i a 43$, aad cyrtopia d\u00C2\u00A3. The supple-mentary hauls i n 20-0 meter\u00C2\u00AE and 10-0 meter\u00C2\u00AE contained more than half of the nauplii and metanauplii, a\u00C2\u00AE i t was evident that the two larval stages weas concentrated i n th\u00C2\u00A9 surface layers. Oalyptopis were also found i n th\u00C2\u00A9 10*43 meters but wer\u00C2\u00A9 more abundant i n 50-0 meters and 100*0 meters, suggesting a deeper distribution. Fureilia were abundant at a l l depth\u00C2\u00AE, but cyrtopia wer\u00C2\u00A9 only found twice i n abundance above 50 meter\u00C2\u00AE. This indicates that the species has a deeper distribution as the animal\u00C2\u00AE develop (Table VI). S\u00C2\u00A9 larval stages of \u00C2\u00A9uphausid\u00C2\u00AE were found in Moveiaber i n the Strait of Georgia. Some sis\u00C2\u00AE variations \u00C2\u00A9eourred, but always within the adult stage. The minimum length found was twenty-nine ram. and some \u00C2\u00A9uphausids were a\u00C2\u00AE long as 45 mm. Total count\u00C2\u00AE i n each sample are given i n fable TH. 71 -T A B 1 E VI LarmL stag\u00C2\u00A9\u00C2\u00A9* by numbers, o f eupaauslds, June a - 16, 1955 Stn. So. Bat\u00C2\u00A9 leptn (a) fSaupHi and Oalyptopis FOTcUla Cyrtopia Mstanauplii 1 June 13 10 1 - -1 \u00C2\u00BB 50 1 I 5 1 2 M 10 1 4 1 -2 W 80 1 3 5 2 4 \u00C2\u00BB 10 4 1 -4 \u00C2\u00AB 100 5 12 12 1 5 \u00C2\u00AB 20 - 1 2 -5 0 200 - 3 *\u00C2\u00BB 10 6 H 50 35 \u00C2\u00BB 3 7 ti 10 1 1 - \u00E2\u0080\u00A2\u00C2\u00BB 7 M 90 1 * 1 i n 5\u00C2\u00A9 - 1 - 17 s n 110 <\u00E2\u0080\u00A2 1 13 9 10 M 10 - 1 \u00C2\u00BB 1 10 H 150 4 2 1 11 M 10 33 18 \u00E2\u0080\u0094 u \u00C2\u00AB 100 - 44 20 11 12 10 74 7 1 3 12 n 50 3 3 4 1 13 8 10 - 2 \u00C2\u00AB. ** 13 tt 50 - 9 17 12 14 June 14 to 4 1 2 1 H 200 11 2 6 3 15 \u00C2\u00AB 10 1 1 1 ** 15 \u00C2\u00AB 150 - 2 6 3 16 4mm 13 10 3 6 <\u00E2\u0080\u00A2 16 \u00C2\u00BB 100 13 8 25 17 20 4 3 3 1 17 \u00C2\u00AB 150 5 8 18 18 12 \u00E2\u0080\u00A2 18 \u00E2\u0080\u00A2Tun\u00C2\u00A9 14 10 - 5 1 18 8 15\u00C2\u00A9 - 1 17 1 19 n 50 7 \u00E2\u0080\u0094 1 19 a 200 8 4 1 \u00E2\u0080\u0094 20 \u00C2\u00BB 20 4 10 5 2 20 250 4 8 11 6 - 72 -WB3t fl (\u00C2\u00A9onoludoa) No. OKU Septa MaupUi MetanaupHi 8\u00C2\u00BBlyptopi\u00C2\u00A9 f t i r o l l i a OjttUpi* 2 1 June 13 2 0 U 46 7 5 1 21 \u00C2\u00AB 1 5 \u00C2\u00A9 ? 133 160 21 2 2 Juno 1 4 1 0 3 1 6 6 \u00C2\u00AB , 2 2 1 0 0 6 6 4 1 23 Juno 1 6 1 0 - \u00C2\u00AB. m 2 3 1 0 0 2 ^ 1* Mm\u00C2\u00A3S%m) **\u00E2\u0084\u00A2 \u00C2\u00AB\u00E2\u0080\u00A2* abundant, \u00C2\u00A3 . ser^dspim i\u00C2\u00AE typical \u00C2\u00A9f the warmer water\u00C2\u00AE of the Strait l a summer. Aeeordiag to Gupp (1943) j|* \u00C2\u00AEemi\u00C2\u00BBpiaa ha\u00C2\u00AE been found .in abundance only i a the Gulf of California* Although i t was not abundant in Hoveaber, i t s \u00C2\u00A9\u00C2\u00A9surreae\u00C2\u00AE together with it\u00C2\u00AE abuadance in the warmer water\u00C2\u00AE \u00C2\u00A9f the .Strait l a June suggest a similar situatiest t\u00C2\u00A9 that recorded by Oupp - a? -(1943)* Johnson (1932) dees not report ]|. M&m&m in abundance from Friday Harbor when the waters in summer reach higher temperatures. As a rule Johnson (1932) never found the species of Rhigosolenia abundant at any time of the year at Friday Harbor. Bi4#tfeM,a fhe genus Biddulnhia was represented by three species, Bid^lpMa a^^SStHa* 1\u00C2\u00BB teWfo \u00C2\u00AB\u00C2\u00AB\u00C2\u00ABI- \u00C2\u00AB \u00C2\u00AE\"ly g. longjcmrif occurred regularly. In fact, i t was universal in distribution, and in June it reached very high ssnee&tratiens. the aeritlc \u00C2\u00A9editions found in th\u00C2\u00A9 Strait of Geor^a seem to account for Its abundance. Allen (1922) and Johnson (lf^2) report that it was new aet with in any considerable numbers at la Jolla and Friday Harbor respectively. Johnson (1932) notes that JU ^ sm&orurlf has been noted in abundance in East Sound, Ores* Island, in Jane, this island is located at the southern end of the Strait. Thalasslonema I l H t e t e l f t rfflMfoW&t. *\u00C2\u00BB* abundant and regular ia distribu-tion in June. It was present in more than two-tMrds of the samples and had its maximum concentration \u00C2\u00A9ff Point Roberts, this genus may have been confused at times with fhalassiothris under the ma^&fioatlw used ia counting. Supp (1943) recognises fhalasslonema as a neritie species very common t*m California to Alaska, whU\u00C2\u00A9 he describe\u00C2\u00AE fhal-assiothrix as oceanic and widespread. Johnson (1932) found ThalaesiothriK nearly always present at Friday Harbor althou# seldom abundant. He does not mention thalasslonema at Friday Harbor. Gran and Angst (1931) d\u00C2\u00A9 not include fnalasglenema to their record of the diatoms \u00C2\u00A9ocurriag - m -at Puget Sound* figure 21 shews the percentage distribution at a depth of ten feet of the four most predominant genera along the Hardy Beeorder \u00C2\u00A9ross-seetiens ( f i g . 1) * Aleut the line A-B, fhalassjesira far ex-ceeds a l l other genera, but on a l l other Maes (C-D, B~P, \u00C2\u00A3Wi) gfeele-tonema is more abundant, except in a few localities where ^haetoeeros \u00E2\u0080\u00A2 J 0 * ffealAssiosim are found in greater number\u00C2\u00AE. Aleag the line 0*\u00C2\u00A9 most of the catch is aad\u00C2\u00A9 up of Skeletoaema and TimXasaioaira. ahaeteceres values are high only in the first few miles of the tow. Th\u00C2\u00A9 line *\u00E2\u0080\u00A2? indteates aaeh hitter numbers of Chaeteceres. Where the percentage Of Chaetoceros diminishes for a few miles in the middle of the tew, Thalasj^iesira, replaces i t and shows relatively high concen-trations* The last erosa-eectioR, 0-S, is a transition line where o\u00C2\u00B0th S^etenema, aad ,|ha^ag.s|\u00C2\u00A7ej^a have high concentrations. The order of magnitude of the phytepiaalgtoa volumes along th\u00C2\u00A9 four cross-sections are presented ia Figure 22. the highest values ar\u00C2\u00AE found opposite Point Robert\u00C2\u00AE on section C-## This are\u00C2\u00AE i s a region ef strong tidal s&xing. On the line A-# values go on increasing frea Point Orey to aabriela Island, but decrease slightly i a the imaediate vicinity of Vancouver Island # latehiasen and Lucas (1931) also observed this phonemes\u00C2\u00A9\u00C2\u00A9. Along the line B-F, values ar\u00C2\u00A9 ia very close agreement wit* those \u00C2\u00A9f Hutehinson aad Lucas* A alight increase is found south \u00C2\u00ABff Texada Island, but value\u00C2\u00AE g\u00C2\u00A9 \u00C2\u00A9a decreasing northward. The volume\u00C2\u00AE enceuatered around Stations 37 and 38 correspond t\u00C2\u00A9 those found at the mouth ef Vancouver iarbour. The line S-B again agrees with th\u00C2\u00AE finding\u00C2\u00AE \"5d 25 - 89 -K A L A b S I O S I R A &p. THA L A S S I q NE \u00C2\u00A3 A S p. S K E L E T O N E M A COS T AT U M A 3 9 12 D i stonee 19 18 in miles 21 24 SKELETONEMA iO 15 2 0 25 30 Distance in miles 39 75 % 50 25 \ / \ / V 2JUELE.T0NEMA_ -COSTA TU M CH AET OCE H OS Sp. \u00E2\u0080\u00A2THALASSIONEMA sp. THALA&5IQS ! R h Sp. 5 10 15 20 25 30 35 D i s t a n c e in miles 40 *5 75 50 25 SKELETONEMA COSTATUM G 3 Fig.21. 6 9 12 15 18 D i s t a n c e in mites 21 T H A L A S S I O S J R A sp. 24 27 H 4 -91-of Hutchinson and Lucas. Volumes of diatoms increase steadily south-ward until they reach their asaimum opposite Point Roberts, they then decrease steadily in the last few miles ef the section, fhe only cross-section which does not f i t in with their results i s the f-sh&ped line opposite the Fraser l i v e r . The values obtained in this cross-section (G-H) are much higher than those found \u00C2\u00A9a the line A - B . However, knowing the seasonal variation that ean occur both ia phyte plankton abundance and all tb\u00C2\u00AE physical and chemical factor\u00C2\u00AE operative from year to year, i t is not surprising to find some inconsistencies between data reported for 1932, and that obtained ia 1955\u00E2\u0080\u00A2 - 92 -1. turlng th\u00C2\u00AE summer when oeeanographi\u00C2\u00A9 conditions la the strait ef Georgia vary widely a great variety of organisms is found. Shoeing the autumn* when the waters reach an almost homogeneous state, the number and Variety of forms diminished considerably* In June, over 34 species of copepods, 45 species of diatoms, and 2? other groups of plankton organisms occurred in contrast with 21 species of oopeoods, 5 species of diatoms, and 19 other groups present in Hovember. 2. Three centers of different concentration of sooplaaktom can be recognised and associated with the physical and chemical characteristics of the waters in the Strait of Seorgia. A) aa area of high concentration with warm surface temperatures and strong wiaiag of water masses} B) an area of intermediate concentration with colder surfaee temperatures and little mixing of water masses| 0} aa area of low concentration with s t i l l colder surface temperatures and little mixing of water masses. 3* The number of diatoms found in June: was low \u00C2\u00ABe\u00C2\u00ABpt*s* with the very high values known from some other area\u00C2\u00AE of the world. The data suggest that the sampling may have preceded or followed a period of greater abundance. The waters north of the Fraser liver contained large quantities of 0baet@oeros aad Skeletonema and those south of the Fraser River showed high quantities of ^ halasslosira and Skeletonema. Few diatoms are taken close to the Fraser River estuary, fhe region Is characterised by very low salinities and high turbidity. * 93 -4\u00C2\u00BB Vertical distribution of zooplankton was apparent and the relative important\u00C2\u00AE of the different groups of plankton organisms varied at 10-\u00C2\u00A9 meters, at 20*0 meters* at 50-0 meters, and deeper. Oopepods are grouped into surface forms, sub*surfaee form\u00C2\u00AE, and deep-water forms. Manv more specie\u00C2\u00AE wer\u00C2\u00AE found in th\u00C2\u00A9 \"upper zone* (50*0 meters) than at greater depth* generally the larval stages inhabited the first few meter\u00C2\u00AE aad the adult\u00C2\u00AE lived at a greater depth. 5. Although th\u00C2\u00A9 artber of specie\u00C2\u00AE of geoplankten and phytoplankton was large culy a small number of forms were deainaat, fhe sopapod\u00C2\u00AE MMmismmm \u00C2\u00AE$\u00C2\u00AE&m* sm^k* MsSm&B* ^ 9mm. *\u00C2\u00BB*>\u00E2\u0080\u00A2 \u00C2\u00AB\u00C2\u00ABtribut\u00C2\u00AEd 65* of all copepods in June and tmiaS^mM $fcPM*> SUte \u00C2\u00ABP*# \u00C2\u00AEad Calanus .finaarchicu\u00C2\u00AE formed 77% of the total number ia lovember. JUL** th\u00C2\u00AE diatom\u00C2\u00AE SM^SBm JggMua* f ^ f e ^ t e m3W*Ms8&b and MSStfaWL \u00C2\u00ABa\u00C2\u00A9e*eu* by far, all other specie\u00C2\u00AE ia June, and ^ osciafdiagu\u00C2\u00AE m&m&l was predeaiaaat in lovember. 6. The rati\u00C2\u00A9 of adult male\u00C2\u00AE to female\u00C2\u00AE was, in some copepod speeies, unequal ia- June and Sovember, the males being more abundant at the \u00C2\u00A9a* set of breeding but later diminishing in nuaber\u00C2\u00AE more rapidly than the female\u00C2\u00AE after th\u00C2\u00AE breeding season* 7. Copepods generally formed the bulk of the ssof&snkUn* fhey were very auwrous in June, but the niwifcers decreased ia Severer. When Juvenile\u00C2\u00AE were very abundant the three dominant sptsios (JmteS&em, ataSSm MM$M l&#*mi*> \u00C2\u00AB*\u00C2\u00BB MMmMsm) responsible. 8. Appa\u00C2\u00BBdi\u00C2\u00A9ulari@a\u00C2\u00AE reached a pe&k in June in region\u00C2\u00AE of optimum temperature for this group (12%). I n such area\u00C2\u00AE they far exceeded 94 the cepeped population and dominated the catch. 9. The population of euphauslds Is found t\u00C2\u00A9 be distributed v e r t i c a l -l y according t\u00C2\u00A9 age. There i s a deeper distribution of the species as the larva\u00C2\u00AE mature. Spawning take\u00C2\u00AE place i n late winter and early spring i n the water of the Strait \u00C2\u00A9f Georgia. 10. Both Juvenile and adult chaetognaths wer\u00C2\u00AE present i n the June catches. Immature forms wer\u00C2\u00AE found i a th\u00C2\u00AE supplementary hauls taken i n 10-0 and .20-0 meter\u00C2\u00AE\u00C2\u00BB Mature form\u00C2\u00AE \u00C2\u00A9\u00C2\u00A9curred i n 50*0 meters aad deeper. I\u00C2\u00A9 larval forms were found i n lovember. 11. The center of abundance for amphipods lie\u00C2\u00AE between 50-0 \u00C2\u00ABet\u00C2\u00AErs i n June and below 50 meter\u00C2\u00AE i n Sovember. Th\u00C2\u00AE shallower June distribu-tion Is l a i d to the presence ef several immature individuals. 12* Over 90$ ef the larvae caught i n June belonged to %re\u00C2\u00A9 group\u00C2\u00AE only* copepod larvae* barnacle larvae* and crab larvae. Gepepod larva\u00C2\u00A9 were i n the upper layer (10-0 mete*\u00C2\u00AE), barnacle larvae were found somewhat deeper (50-0 iaeters)\u00C2\u00BB and crab larva\u00C2\u00AE ware encountered much deeper (100-0 meters)* 13. Diatoms were meat abundant areaad a depth of 10 meters. The western portion ef the Strait supported a higher concentration than the colder* less saline eastern portion. The heaviest concentrations \u00C2\u00A9\u00C2\u00A9curred a l i t t l e south of the Fraser aver estuary in an area of \"steep*5 temperature and salinity gradient\u00C2\u00AE\u00E2\u0080\u00A2 14. The euryhaliae plankton \u00C2\u00A9rgaaisas were found in great abundance during June aad lovember 1955* Their distrttJution i a th\u00C2\u00AE Strait \u00C2\u00A9f Georgia is only slightly affected by the \u00C2\u00A9\u00C2\u00A9\u00C2\u00A9anagraph!\u00C2\u00A9 conditions because - 95 -th\u00C2\u00A9 fluctuations i n th\u00C2\u00A9 physical arid the chemical characteristics of the water l i e within the limits of tolerance of the organisms, the \u00C2\u00A9ten\u00C2\u00A9-haUne plankton organisms are limited to the more stable \"lower son\u00C2\u00AE\" * Within this \u00C2\u00ABl\u00C2\u00A9wer sone\" the abundance and distribution of th\u00C2\u00A9 steno-hallne forms do not vary very much since temperature\u00C2\u00A9 and salinities ar\u00C2\u00A9 f a i r l y constant i n space and time, fhe euryhaline heUephylli\u00C2\u00A9 forms (diatoms) ar\u00C2\u00AE the most abundant, fhey are found i n regime where fresh water originating fro\u00C2\u00AE the Fraser l i v e r aad salte\u00C2\u00A9 water i n the Strait Mx* fhis misdsig process favours pl^ Ftoplankfcoa ataadance to \u00C2\u00ABb . least two ways, fhe mi\u00C2\u00BBd. waters may contain certain physical and chemical factors XmMm In aay one of ti\u00C2\u00A9 fresh and sea water masses alone. Also the eatrainmeat of deeper saline water into the upper sone may bring up nutrients where they are available to phytoplankton. -96 -vn\u00C2\u00BBm Allen, W.S. 192\u00C2\u00AE. Catches cf marine diatoms and dlnoflagellates taken by beat i n Southern California waters* Bull* Scripps Inst. Oceanog. JL (13)j 201-246. Bigelow, H*B. and Leslie, M . 1930* Reconnaissance of the waters and plankton of Monterey Bay. BmU. Mas. Comp* Zool. UEZ (5)\u00C2\u00AB 430-5T3. Cameron, A.T. and Mounce, 1* 1922* B&m physical and chemical factors influencing the distribution of marine flora and fauna in the Strait of Georgia and adjacent waters* Gent* Can. Biol* \u00C2\u00A3t 41-70. Cameron, F.E. 1955. Boa\u00C2\u00AE factors Influencing the distribution of pelagic copepod\u00C2\u00AE in the Queen Charlotte Islands area* Masters Thesis, Univ. British Columbia Dept. Zool. (unpubl.). eaapbell, 8*1. 1929. Some fr@#-swimaing copepods of the Vancouver Island region, trans* Soy. So\u00C2\u00A9. Can. XXIII (l)t 303-332. Campbell, M.H. 1934* The life-history and post-embryonic development of th\u00C2\u00A9 copepods, Calanus tonsus Brady and Euchaeta .toonioa Marukawa* J . Biol* Board Can* \u00C2\u00A3 (l)s 1-65. Supp, B.E* 1943* Marine plankton diatoms of the west coast of lorth America* Bull* Heripps Inst. Oceanog. \u00C2\u00A3 (1): 1-238. Dakin, W.J. and Colefax, A.N. 1940. The plankton of th\u00C2\u00AE Australian coastal waters off New South Males* Univ. Sydney Publ* Zrnl* Ifcaogr* Is 1-211. Davis, C C . 1949* Th\u00C2\u00A9 pelagic copepods of the Northeastern Pacific Ocean* Univ. Wash. Publ. B i o l . 3^ s 1-113. Pawydoff, C f / / / 1923. 1'raite d 'eabryologl\u00C2\u00A9 compares? des invertebres. Masson et Cie, Paris* 930 PP\u00C2\u00AB 97 * ^ P ^ S P (eontinued) Bsterly, 0.0. 1905* The pelagic copepoda of. th\u00C2\u00AE San Diego region. Oniv* Calif. Publ. Zool. 2s 113-233* 1926. Th\u00C2\u00AE periodic occurrence of \u00C2\u00A9opepoda in the marine plankton \u00C2\u00A9f two successive years at La Jolla, California. Bull. Scripps Inst. Oceanog. 1 (I4)s 247-345\u00E2\u0080\u00A2 Fraser, CM. 191S. Migration\u00C2\u00AE of marine animals. Trans. Boy. So\u00C2\u00A9. Can. I?i 139-143* Siesbrecht, tr\u00C2\u00AB 1892* Systematik und Faunistik der pelagisohoa Copeeden des Oelfes von fJeapel und der angrenaeaden Meeresabschnitte. Fauna und Flora de\u00C2\u00AE Golfes von Heapel, Menog. XlXr 1-831* Gran, U.U. and Angst, E*C\u00C2\u00AB 1931 \u00E2\u0080\u00A2 Plankton diatoms \u00C2\u00A9f Puget Sound. Publ* Puget sound Hoi* Stat. 2\u00C2\u00AB 417-519* Hardy, A*0. 1939* Bcelogioal investigatiea\u00C2\u00AE with th\u00C2\u00AE \u00C2\u00A9ontinuetta plankton recorder: Object, Plan, and Usthod\u00C2\u00AE. Hun Bull. Kar. Seel* 1 (l)t 1-57* Hart, J.f * 1942* Phytoplankton periodicity in Antarctic surface waters. Disc. Sept. XXIJ 261*356. Hutchiasoa, A*H* If28. A ble-bydrographieal investigation of the sea adjacent to th\u00C2\u00AE Fraser river mouth. Trans* Roy. Soc. Can. XXII (5)\u00C2\u00BB 293-310. Hutehiasen, A.H., Lucas, CO* and ftePhail, M. 1929. Seasenal varlati\u00C2\u00A9\u00C2\u00AE\u00C2\u00AE in th\u00C2\u00AE chemical aad physical properties of the waters of the Strait of Georgia in relation to phytoplankton. Tran\u00C2\u00AE. &\u00C2\u00AEy. Soo. Can. XXIII (5)t 177-183\u00E2\u0080\u00A2 Hutchinson, A.I. aad Lucas, 0*0* 19J1. The epithalssea of th\u00C2\u00AE Strait of Seergi\u00C2\u00AE. Can* Jour. Be\u00C2\u00AE. \u00C2\u00A3t 231-204* - 9 8 -fCiS (continued) Jespersen, P. and Russell, F.S. 1949- Piehes d'identification du zooplankton. 1952. 0\u00C2\u00AEas\u00C2\u00BB Perm. Int. Expl. Mer 1*50. Gopenhague. Johnson, M.M. 1932. Seasonal distribution of plankton at Friday Harbor, Washington. Univ. Wash. Publ. Oeeaaog. I (l)t 1-38* King, J.E. and Demond, J. 1953* Zooplankton abundance in the central Pacific. Fish. Bull. ,8J (54)t 112-142. lea, H\u00C2\u00ABS* 1955* The chaetognaths \u00C2\u00A9f western Canadian coastal waters. J. Fish. Ees, Bd. Can. i g (4)t 593-61?. Le Brasseur, E.J. 1955* Oceanography of British Columbia Mainland Inlets. VX. Plaifcton distribution. Prog. aept. Pac. Coast Stns. Can* 10$t 19-21. Lucas, C.C. and Hutchinson, A #8. 192?. A bie-hydregraphle&l investigation of the sea adjacent to the Fraser river m\u00C2\u00A9uth. Trans. Roy. Soc. Can. XXI (5)? 485-520. Marshall, S.M. and Orr, A.P. 1927* The relation of th\u00C2\u00A9 plankton to some chemical and physical factere in th\u00C2\u00A9 Clyde sea area. J. Mar. Biol. Assoc. B.K\u00C2\u00AB J\u00C2\u00A3i 837-868. Euad, J.T. 1932. Oa the biology of southern Euphausiida\u00C2\u00AE. BvaUradsts Skrifter 2: 1*103. Sars, 0.0. 1903. An account of the Crustacea of Morway* Bergen Jteeum. ^ Copepoda Calaaoida* n/ pp. 1911. Ibid % and 6 Copeped\u00C2\u00AE Barpacticoida. pe Sverdrup, H.U., Johnson, M.W. and Fleming, l.H. 1954. The Oceans. Preutice*iiall. l\u00C2\u00A96l pp. Tully, J.P. and Dodlmead, A.J. 1954\u00E2\u0080\u00A2 Properties of the water la Georgia Strait, (unpuhl* manuscript). Wailes, O.H. 1939* Protozoa, le Mastigophora. Can. Pac. Fauna It k5 PP* Wa],diohiik, M. 1952. Oceanography of th\u00C2\u00A9 Strait \u00C2\u00A9f Georgia. 1 .Salinity Distribution* Prog. Rept. Pas. Coast Stns. Can. \u00C2\u00A3|t 26-29* 1953* Ibid. 2 . Temperature Distribution. Prog. Rept. Pac. Coast Stns. Can. 19-23* 1955* Physical Oceanography of the Strait of Georgia, British Columbia. Doctoral Dissertation* Univ. Wash. Dept. Oceanog. (tmpabl.)* Wilson, CB. 1932. The copepods of the Woods Hole Region, Massachusetts. 94. Mat. Mus. Ball. jj5j* 1-625. "@en . "Thesis/Dissertation"@en . "10.14288/1.0106987"@en . "eng"@en . "Zoology"@en . "Vancouver : University of British Columbia Library"@en . "University of British Columbia"@en . "For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use."@en . "Graduate"@en . "The qualitative and quantitative distribution of plankton in the Strait of Georgia in relation to certain oceanographic factors"@en . "Text"@en . "http://hdl.handle.net/2429/41665"@en .