ARCEPVES FISHERIES RESEARCW. BOARD OF CANADA Translation Series N 2498 ' . Influence of thetrophic factor On thé population 'and distribution of the sea otter in the central and northern • Kurile Islands bY M: Shitikov Original. title: Vliyanié troficheskogo faktora na. chislennostli . raspredelenie. kalana na.srednikh .ostrovakh . ,• • . • . .« . From: TrudY.Vsesoyuznoge-Nauchno-IssledovatelSkogo • • Instituta -Morskogo Rybnogo Khozyaistva Okéanografii '(VNIRO) Vol. 82 (proceedings of , the AllUniOn• Research institute of Marine ' Fisheries and Oceanography). Izvestdya 'Tikhookeanskogo. Nauchno-IsSledovatel. 'skogo instituta RYbnogo. , Khozyaistva d Okeanografii .(.TINRO) Vol.' 80 (Proceedings of the Pacific Scientific Research . - ' Institute of Marine Fisheries and ObéandgraPhy) . , 82 _& 80 '227-239,. 1971 • '' Translated by the Translation'. •Eureau (IPST1 . Foredgn,4anguages Division. • Hi.'; Department-Of the.Secretary . of Stateof Canada' • . Department of.' the Environment.- Fisheries_ReSearch'Board 6f Canada ' 'ArctiC Biological:Statdon. *Ste. Annede Bellevue', 1973 22 :pages typescript .D--'PARTMENT OF THE SECRETARY OF STATE . SECRETARIAT WETAT FRR ;-1 TRANSLATION BUREAU . BUREAU DES TRADUCTIONS . MULTILINGUAL SERVICES r" DIVISION DES SERVICE S CANAD A DIVISION MULTILINGUE S TRANSLATED FROM - TRADUCTION D E INTO - EN Russian English IAUTHOR - AUTEU R ~''A .M . Shitikov, TINR O JITLE IN ENGLISH - TITRE ANGLAI S ~Influence of the Trophic Factor on the Population and Distribution of the Sea Otter in the Central and Northern Kurile-Islands . TITLE IN FOREIGN LANGUAGE (TRANSLITERATE FOREIGN CHARACTERS) Ti TRE-EN LANGUE ~TRANG~RE (TRANSCRIRE EN CARACTERES ROMAINS ) Vliyanie troficheskogo,faktora na chislennost'i raspredelenie kalana na srednikh i severnykh-Kuril'shikh ostrovakh . REFERENCE IN FOREIGN LANGUAGE (NAME OF BOOK OR PUBLICATION) IN FULL . TRANSLITERATE FOREIGN CHARACTERS . REFERENC -1 EN LANGUE ETRANGERE - (NOM DU LIVRE OU PUBLICATION) . AU COMPLET, TRANSCRIRE EN CARACTÈRES ROMAINS . VNIRO,vol . 82/TINRO Vol-80 REFERENCE IN ENGLISH - R~FERENCE EN ANGLAI S PAGE NUMBERS IN ORIGINAL DATE OF PUBLICATION - NUM9ROS DES PAGES DANS DATE DE PUBLICATIO N L'ORIGINA L YEA~ ISSUE NO. .227-239 = RP1 2 VOLUME NUMERO ,.~--PI~ACE,017 PUBLICATION ANNE E NUMBER OF TYPED PAGES - LIEU dE PUBLICATION NOMBRE DE PAGES DACTYLOGRAPHIEE S 1971 - 2 2 . :,,REQUESTING DEPARTMEN T Environment MINISTERE-CLIEN T ,BRANCH OR DIVISION TRANSLATOR (INITIALS) -DIRECTION OU DIVISION TRADUCTEUR (INITIALES ) MIEDIT!_D: TRANSLATI-01~ For iriforma,-iori only TRADLI.C' 3N., NON REVI 5EE:. Infor.malio'l SCUIOM~-nt I ' DEPARTMENT OF THE SECRETARY OF STATE SECRÉTARIAT D'ÉTAT re8 »ici8 TRANSLATION BUREAU BUREAU DES TRADUCTIONS MULTILINGUAL SERVICES DIVISION DES SERVICES DIVISION CAN ADA - • MULTILINGUES CLIENTS NO. DEPARTMENT DI VISION/BRANCH CITY N P DU CLIENT MINISTRE. DIVISION/DIRECTION VILLE EN V IRON:1NT FISHER.IES RES. 13W. St. Anne de Bellevue QL.1 0. 1, BUREAU NO. LANGUAGE TRANSLATOR (INITIALS) N° DU BUREAU LANGUE TRADUCTEUR (INITIALES) L43731 Russian IPST APR 3 1973 227 _From: Trudy VNIRO, Vol. 82 and lzvestiya TINRO, Vol. 80, 1971, pp. 227-238. 599.742.4 INFLUENCE OF THE TROPHIC FACTOR ON THE POPULATION AND DISTRIBUTION OF THE SEA OTTER IN THE CENTRAL AND NORTHERN- KURILE ISLANDS (Vliyanie troficheskogo faktora na chislennost' i • LINEDITZD na srednikh i severnykh raspredelenie kalana TRANSLATION Kuril'skikh ostrovakh) .Por inforrna'don only TRAID:XTKL)N NON REVISEE A. M. Shitikov, TINRO Infornlailon soulement The sea otter (E nhy dr a lutr is L.) now occurs on almost all the islands of the Great Kurile Ridge north of Kunashir and numbers 4,000-7 The question of the further growth of the population is controversial. 5,000. A. N. Belkin (1966) and later S..K.Klumov (1968) estimated that the sea otter population on the Kurile Islands should attain 7,000-10,000 by 1970; Belkin considered the latter figure as the limit for the area. In his opinion, the number on each island will increase due to both natural growth and to animals' .corning in from other Islands, thus making it unnecessary for more to be introduced by man. This view was shared by I. I. Barabash- Nikiforov, S. V. Marakov and A. M. Nikolaev (1968). Klumov (1968), on the other hand, thought that 10,000 is not the limit for the Kurile Islands. ‘.;305-43001 0-3 I This number will be made up mainly by the growing populations on the islands of Urup and Paramushir, whi.c3.i is liable to cause an epizooty on these islands. He suggests that more sea otters be brought in to increase their number on the other islands. Data of the latest counts show the sea otter population to _be growing very. slowly, not yet having, reached 10,000. On some islands, the number of animals has not been increasing for the last 10-15 years. Thus, 200 sea otters inhabited Onekotan Island in, 1955 (Klumov, 1957), 139 in 1963 (Belkin, 1966), 69 in 1967 (Nikolaev, 1968), and 64 in 1970 (our data). No count has been made on the islands of Urup, Shikotan, and Makanrushi since 1963, although the initial populations there-were fairly large. 'The distribution by island has also changed little since 1963, and about 70% of the entire population is still concentrated on the shores of Urup and Paramushir islands. The sea otters flock together mainly at the tips of the islands and on their eastern shores. In the central and northern Kurile Islands, they have„appàrently settled in all the suitable habitats. The creation of new habitats calls for a study to establish the biotope required by the animal. ^ 228 Numerous observations have •now made it possible to identify the sea otter's haunts. The first professional hunters had noticed that "kelp-rich rocky promontories and reefs are favbrite hideouts of the beaver. .." and that .''beavers keep mainly to the ends of thëislands and their Pacific sides". (Snow, 1902). These habits have,s'till not changed. Barabash-Nikiforov, (1947), observes that sea otters are attraeted.bÿ, steep or relativèly gently sloping, rocky shores, .. ;,^> _. ^ . - .. _ :. .. .. barrier reefs, little rocky islands, around which the Stirf consta.ntly breaks, .and finally, clumps of kelp which for m a j'agged S trip "along the shore. According to the presence of reefs and rocky islets in the offshore area of the sea, the size of the seaweed fields, the nature of thé littoral and sublittoral, the depth of the sea and the. distance from the extreMities Of the islands, Nikolaev (1963) suggests a tentative classification of the Sea otter haunts into four categories: excellent, good, fair, and poor. AmeriCan 'c-m5logiStà (Èyerdam, 1933; 1938;' Williams, 1959, 1963; .Kenyon, 1965) alSO hotiCed the animal's predilection . .for areas with rocky shores .and -abundant reefs ; tôéky islets and kelp. Nevertheless, it is not enough tô know the ablotic Conditions of life in order to be able to establish the catt8e8 that deterMine thé ntunber . and distribution of the population, as theSe depend ôn the trôphic faetôt às well. But the importance of this factor has not been Studied at all. With • .reference to the Paramushir .population, the diStribution of the animals on Paramushir Island and the eastern Shore Of Kamehatka has been• 'shown tà depend on the abunda-nce ôf food iternS in the areaS where a certain trophic group'of benthos developS: the iMmobile Seg-Eônophages. To study the distribution of food items for the Sea ôtter on the other islands and to collect data on its feeding habits, TINRO organized a series of expeditions in the central.and northern Kurile Islands in 1969 and 1970. The investigation was carried out by the trapping boat "Krylatka." A group of scuba divers participated in the research cruiSeS. The Urup, Chirpoi (Chernye.Uratya-),..Sinuskr an:kicha (Ushishir), Paramushir,..Ilatua,:AntSiferov - and Psttàsov iSlands Were investigated. The areas of work are indicated on the figure. Number and distribution of sea otters in the central and northern Kurile Islands: 1 — about 100 specimens; 2 — about 50 specimens; 3 — about 25 speci- mens; 4 — about 10 specimens. In the study of macrobenthos of the Kurile Islands sublittoral, invertebrates and algae were counted by the method of hydrobiological sections of incomplete profile, the stations located at the depths of 5, 10, 15 and 20m. A: few stations were taken to a depth of 30-40m. The number of sea otters was determined, excrement was collected and analyzed, and the contents of stomachs and intestines were examined at the same time. In all, 1,429 excrements and the contents of 60 stomachs and intestines were investigated. The frequency of occurrence of a food item and its predominance in the food . 5 (i. e. more than 50% of the overall volume of the excrément, by visual assessment) were carefully studied. Whenever the excrement consisted of equal parts of two or more kinds, preference was given to that which contained less hard parts: the remains-of octopuses were given priority over remains of-fish, fish to crab, crab to -sea urchin, and so on. Thus, whereas the first index can serve as a qualitative characteristic of feeding, the second one is quantitative. These.indexes were also used when.analyzing the contents of stomachs and intestines. In this case, the predominant kind. of food was determined not only by'visual assessment, but also by weighing. 229 The feeding habits of the sea otter on the Kurile Islands have.been little.. described in the.literature. K. Miyatake (1940) studied the suzniner diet; after analyzing the contents of the stomachs of 332 sea otters, he came to the conclusion that the main food items were Oc t o p u s d o f 1 e i n i, the Sakhalin sea urchin Strongylocentrotus sachalinicus;thè mussel Mytilus eduli.s, and the fish Hexagrammus otakii, Sebastichus sp., and Cycloptericht-hys .ventric.osus. Unfortunately, the author Aid not mention where the investigations were carried out.