Translation 3081
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FISHERIES AND ►4AARINE SERVICE Translation Stleries No. 3081 Spawning of the Alaska pollock Tfzera a chalcoc^ramma (Pallas) in the ncrtheastern part ô^ t^Bering Sea By I.I. Sérobaba Original title: Nerest mi.ntaya Theraqra dzalcoqranana (Pallas) v sevexn-- vOstocnnoi ctias.t From: Izvestiya T•ikhookeanskogo Nauchno-Issledovatél'skogo Tnstitùta -Rybnogo.Rhozyaistva i Okeanografii (TINRO) Voprosy ikiztiôlogii_ (Proceeclings of the Pacific Scientifiç ibseàrch Institute of:Marine . Fisheries and Oceanography (Prc,blem5 relating to ichthyolcgy) ); 8(6(53)) : 992-1003, 1968 `i'ra,nalàted by the Translation Bureau ( GAD) 1.2u•1.ti13n8ua1 Services Division. Departmqnt of the Secretary of State of Ganada ïlepmrtment of the EnerironmQnt Fisherieffi. and Marine Service Biological Station Nanaimo, B..G. 1974 27 pages typescript , • DEPATMENT OF THE SECRETARY OF STATE SECRÉTARIAT D'ÉTAT TRANSLATION BUREAU BUREAU DES TRADUCTIONS MULTILINGUAL SERVICES DIVISION DES SERVICES DIVISION MULTILINGUES F15-4_,3 ôjjizi TRANSLATED FROM — TRADUCTION DE I NTO — EN Rus sian English AUTHOR — AUTEUR 1.1. Serobaba TITLE IN ENGLISH — TITRE ANGLAIS Spawning of the Alaska pollock Theragra chalcogramma (Pallas) in the northeastern part of the Bering Sea TITI- E IN FOREIGN LAIIGUAGE ( TRANSI I TERATE FOREIGN CHARACTERS) TITRE EN LANGUE ÉTRANGÉRE (TRANSCRIRE EN CARACTLRES ROMAINS) Nerest mintaya Theragra chalcogramm% (Pallas) v severo-vostochnoi chasti Beringova morya REFF.RENCE IN FOREIGN LANGUAGE (RAME OF BOOK OR PUBLICATION) IN FULL. TRANSLITERATE FOREIGN CHARACTERS. RÉFÉRENCE EN LANGUE ÉTRANGÉRE (NOM DU LIVRE OU PUBLICATION), AU COMPLET, TRANSCRIRE EN CARACTÈRES ROMAINS. Voprosy ikhtiologii REFERENCE IN ENGLISFI — RÉFÉRENCE EN ANGLAIS Problems relating to ichthyology PUBLISHER ÉDITEUR PAGE NUMBERS IN ORIGINAL DATE OF PUBLICATION NUMÉROS DES PAGES DANS Not given DATE DE PUBLICATION L'ORIGINAL 992-1003 YEAR ISSUE NO. VOLUME PLACE OF PUBLICATION ANNÉE NUMÉRO NUMBER OF TYPED PAGES LIEU DE PUBLICATION NOMBRE BE PAGES DACTYLOGRAPHIÉES Not given 1968 8 6(5'3) 27 REQUESTING DEPARTMENT -- TRANSLATION BUREAU NO. -I .1.0)U,D MINISTRE-CLIENT Environment NOTRE DOSSIER N0 F3RANCH OR DIVISION TRANSLATOR (INITIALS) G.A.D. Fisheries Service--..--- DIRECTION OU DIVISION TRADUCTEUR (INITIALES) PERSON REQUESTING Dr Sotie Westrheim, Nanaimo DEMANDÉ." PAR YOUR NUMBER VOTRE DOSSIER 11 0 DATE OF REQUEST 1974 DATE DE LA DEMANDE January 28, SOS.200-10-6 (FI E V. 5/68) 7 G30-21-029-5333 DEPARTMENT OF THE SECRETARY OF STATE SECRÉTARIAT D'ÉTAT • TRANSLATION BUREAU BUREAU DES TRADUCTIONS MULTILINGUAL SERVICES DIVISlOh! DES SERVICES DIVISION MULTILINGUES CLIENT'S NO. DEPARTMENT DIVISION/BRANCH CITY NO DU CLIENT MINISTERE DIVISION/DIRECTION VILLE Environment Fisheries Service Nanaimo, B.C. BUREAU NO. LANGUAGE TRANSLATOR (INITIALS) NO DU BUREAU LANGUE TRADUCTEUR (INITIALES) 165653 Russian GAD J014 Voprosy ikhtiologii, Vol. 8, No. 6 (53), 1968, pp 992-1003. ION UDC 597.0/5-11. I<M:^ 'éï^ ^ ^^t:^^..:^ski P {^ V Spawning of the Alaska pollock Theragra chal.cogramma' ";"tDUC , (Pallas) in the northeastern part of the Bering Sea By I.I. Serobaba (Pacific Ocean Scientific Research Institute of Fisheries and Oceanography - TINRO - Vladivostok). 992* The spa^,ming area of the Alaska pollock, which inhabits the northeastern shelf of the Bering Sea, is bounded by the ice- edge on one side and the continental slope on the other. The spawning grounds extend along the 50-300 meter isabaths from Unimak Island to 179° W.L. The total area of the spawning grounds is 175,000 lr.m2. Spawning takes place from the end of February until June. The eggs of the Alaska pollock are distributed r,iainly at depths of 50 to 300 meters. The greatest amount of eggs is observed in the southeastern area of the spawning grounds. *Nnmbers in the right-hand margin indicate the corresponding page numbers in the original. SOS-200-10-31 7530-21-029-5332 2. Soviet and foreign researchers (Rass 1949, 1965; Gorbunova, 1952; Pertseva-Ostroumova, 1961; Thompson and Van Cleve, 1936) have proven that the method of estimating the quantitative distribution of eggs is sufficiently accurate for the determination of the places, time and conditions of spawning. In addition, it is possible in practice to estimate the size of schools of spawning fish according to the abundance of floating eggs /Rass, 1949; Vedenskii, 1949; Kashkina, 1965/. Due to the fact that the number of eggs shed exceeds by tens and hundreds of thousands of times the number of spawning females, it is much more easy to find the floating eggs in the sea than the less numerous spawners, which are in addition much more difficult to catch /Rass, 1965/. Material collected in connection with analyses of mature in- dividuals only is insufficient to determine the conditions and nature of spawning. The fish car be in a prespawnirg condition for a long time before shedding eggs. In addition, females sometimes eject eggs as a resuli of the mechanical action of the fishing gear. Therefore, in study- ing the biology of the Bering Sea pollock on the expeditionary ship "Seskar" of the Far Eastern Scientific - Commercial Exploratory Fishing Service of the Pacific Ocean Scientific Research Institute of Fisheries and Oceanography (DDNPPR TINRO), in the spring-summer period of 1965, we carried out an ichthyoplankton survey to determine more precisely the time and areas of spawning of the pollock. The work site was the shelf of the northern and eastern parts of the Bering Sea from Unimak Island to Cape Navarin. 1 Ichthyoplankton was collected with a standard conical net (IKS- 80) at depths of 50 to 1000 meters. Samples were taken by the methods of vertical total and surface catches at'all stations, except for those stations where for any'reason it was not possible to use one of the methods. 3. In all, 333 catches were made» 190 samples were taken by the method of total catch; in these the eggs of the Alaska pollock were discovered at 116 stations, while larvae were also found at some stations (figure 1 and 2). The material collected was processed in the laboratories of Moscow University and the Institute of Oceanology of the Academy of Sciences of 1 the USSR (MGV and IOAN) . Maps of quantitative distribution were compiled by interpolation 993 according to the results of the egg count (Zaitsev, 1935). To determine spawning sites, catches of eggs which were at initial stages of develop- ment were plotted on the map, and to obtain a picture of the drift of developing eggs, maps were compiled of the quantitative distribution of eggs at later stages of development/Rass, 1949/. The results of. the vertical catches only were used in preparing maps. Eggs were measured by means of an eyepiece micrometer. The stages of egg development were determined according to the 4-point scale of Rass, /1933, 1946/which is used in processing mass collections, and on this basis the percentage ratio of stages of development in the sample were calculated in order to judge the time and progress of spawning of Alaska pollock. Two ichthyoplankton surveys (figures 1 and 2) were performed in the water area of the shelf from Unimak Island to Cape Navarin in the spring-summer period. The region of the first survey was bounded by ice- edge, and the outer stations were sometimes located among ice fields. The ichthyoplankton survey was begun in the middle of February. Work was carried out in the water area from Unimak Island to the Pribilof Islands 1 The author would like to express hi S sincere thanks to Professor T.S. Rass and A.A. Kashkina for their valuable advice and critical comments. 4. 170 ieo CO 65 170 160 • Pile. 1. Pam:owl:el-me ux.mormanIzTonumx CT8.11Mlii n ceBepo-Boczolmort na- Bepuuropa. mops' ( .fapT — Mail 1965 r.). 1— BeFrimaahnue li ropu3ormah- Flb10 310B11; 2 — BepTiniaamme :rionbl; 3 — 11013epX110CT111,10 1130TOPMLI Figure 1. Location of ichthyoplankton stations in the northeastern part of the Bering Sea (March - May 1965). 1 - vertical and horizontal catches; 2 - vertical catches; 3 - surface isotherms; a - St. Matthew Island; b - Nunivak Island; c- Pribilof Islands; d- Unimak Island. at the end of February and beginning of March, where some individuals had already begun to spawn. Alaska pollock eggs were found for the first time on February 27th. Single egg finds were also recorded on March 9th and 12th. Eggs began to be found in massive amounts (up to 100 and more 2 eggs per 1 m ) only at the end of March. In the second half of March and in April, observations were carried out only in the area of the Pribilof Islands. Unfortunately we were unable at this . time to carry out work near Unimak Island, where large prespawning accumulations of pollock were forming. Still, it is possible to estimate the time of beginning of spawning according to 5. data Obtained in the Pribilof region at the end of March (110 eggs per 2 1 m ). All the eggs taken were at the initial stages of cleavage. Up 2 to 70 prolarvae and larvae of Alaska pollockperim were observed here, apparently brought by the current from the southeastern part of the sea. Abcordin.g to the data of A.K. Leonov /1960/, the rate of movement of the 'Pacific Ocean water masses along the Aleutia.n island chain and in the 994 seutheastern part of the Bering Sea reaches 0.3 m/sec. It is of course doubtful that these larvae could have developed from eggs shed here, «since hydrological conditions in this area are much more severe than in the southeastern part of the sea.- In -April, work was carried out to the west of 1700 -where the :region 'under study was -delimited by -natural «boundaries - the ice- -edge on the -northeast and -the drop-off on the southwest,.