TRANSLATION 3185 3 of 7 E, ,Oa^^M^E° Eiee^Ervee°E,Eee°°A SERIES NO.(S) Ser^Ce Ien,E^ UDC 599.74-5.2 0 V

inCIDEa cl 0.• FISHERIES:AND MARINE SERVICE

TranslatiOn:Series No. '3185

Research on marine mauunals

by K.K. Chapskii, and (Editor). E.S. Mirchenko

Original. title: ssledovaniya morskikh miekopitayushchikh

From: Atlanticheskii:Nauchno-Issiedovaterskii Institut Rybnogo Khozyaistva'l Okeanografii (AtlattNIRO) (Transactions of the Atlantic Scientific Research. Institute of Fisheriep and_OceanographY), (39), : 1-344, 1971

Translated by the Translation Bureau( JNO,) Multilingual Services Division . Department of the Secretary of State of Canada

DepartMent of the Eayirtùlment, YisherieS and Marine Service .Arctic Biological: Station Ste. Anne de Bellevue, 1974 • -

562 pages typescript iI DEPARTMENT OF THE SECRETARY OF STATE SECRÉTARIAT D'ÉTAT TRANSLATION BUREAU BUREAU DES TRADUCTIONS

MULTILINGUAL SERVICES DIVISION DES SERVICES CANADA DIVISION MULTILINGUES

TRANSLATED FROM - TRADUCTION DE INTO - EN

s S 1 a n En^lish

AUTHOR - AUTEUR 5; r^os i ur:^ volume. In charge of issue - K. K. Chapskii. ^.',ditor. -. E . S. r..il Cl:enkO TITLE IN ENGLISH - TITRE ANGLAIS

:;esearch on I..arine ::ammals

TITLE IN FOREIGN LANGUAGE (TRANSLITERATE FOREIGN CHARACTERS) TITRE EN LANGUE ETRANGERE ( TRANSCRIRE EN CARACTÉRES ROMAINS)

ïsslec3ovc.niya -morskikh rnlekopitayushchikh

REFERENCE IN FOREIGN LANGUAGE (NAME OF BOOK OR PUBLICATION) IN FULL. TRANSLITERATE FOREIGN CHARACTERS. REFERENCE EN LANGUE ETRANGERE (NOM DU LIVRE OU PUBLICATION), AU COMPLET, TRANSCRIRE EN CARACTÈRES ROMAINS.

Atlanticheskii naucYrno-issledovrl.tel'skii institut ryno`;o

lçI_^ oz,,cr ai st v^^^ i. o_s1 eano `.r ra.^^.^' i ( 1itla.nt " 1 RL Ti^udvry vypusk ^i.^.: 1X.

eEFERENCE IN ENGLISH - REFERENCE EN 1NGLAIS 1^la.^itic eseG.rch ^.nsti.tl.te f or ii.sheri es s.ncl c.^ce_o,_a.-)hy (tlanti;SR ), Transactions . lssue X.iYi^X PAGE NUMBERS IN ORIGINAL PUBLISHER- EDITEUR DATE OF PUBLICATION NUMEROS DES PAGES DANS DATE DE PUBLICATION L'ORIGINAL t18.nti- ; lI^U YEAR ISSUE NO. - 31,.1;. VOLUME I NUMERO PLACE OF PUBLICATION ANNEE NUMBER OF TYPED PAGES LIEU DE PUBLICATION NOMBRE DE PAGES DACTYLOGRAPHIEES nin^r^.cl -49 5 E2

TRANSLATION BUREAU NO. ^ ^^a3 REQUESTING DEPARTMENT ^^^rrvironment MINISTRE-CLIENT NOTRE DOSSIER NO ^ r'i sl:eri es and I,.arine Services BRANCH OR DIVISION TRANSLATOR (INITIALS) J( . il o . DIRECTION OU DI VISION . L'f Lice . Of the ^•di-^Or TRADUCTEUR ( INITIALES)

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SEP. 12 1974.

SOS.200.10.6 (REV. 2/08) 7030•21.OZ9•5333 DEPARTMENT OF TP;E SECRETARY OF STATE SECRÉTARIAT D'ÉTAT TRANSLATION BUREAU BUREAU DES TRADUCTIONS

MULTILINGUAL SERVICES DIVISION DES SERVICES DIVISION MULTILINGUES

CLIENT'S NO. DEPARTMENT DIVISION/BRANCH CITY N° DU CLIENT MINISTÉRE DIVISION/DIRECTION VILLE Fisheries and Marine Ser - Environment vices, Office of Editor

BUREAU NO. LANGUAGE TRANSLATOR (INITIALS) N° DU BUREAU LANGUE TRADUCTEUR (INITIALES) 165703 Russian J. No. eEp 1 2 1974

Atlanticheskii nauchno-issledovatel'skii institut rybnogo khozyaistva î okeanografii (AtlantNIRO)

ISSLEDOVANIYA MORSKIKH MLEKOPITAYUSHCHIEH

Trudy, vypusk XXXIX

Kaliningrad 1971

• Atlantic Research Institute for Fisheries and Oceanography (AtlantNIRO)

RESEARCH ON MARINE MAMMALS Transactions, Issue 39

Kaliningrad 1971

UNEDITED TRANSLATION For inforrnalion only UDC 599.5 +599.7145 TRADUCTION NON REVISEE Inforrnalion soulement

In charge of issue: Doctor of Biological Sciences K. K. Chapskii

Research on marine mammals. Transactions, issue 39. Kaliningrad, AtlantNIRO, 1971. 344 pages with illustrations.

SOS-200-10-31

7B :10 -P1.02 Q - 5332 2

Important questions concerning the ecology, distribution, commercial exploitation, morphology and physiology of marine mammals are touched upon in this symposium, as are problems concerning the conservation and maintenance in captivity of these animals. The wide range of themes will undoubtedly be of interest not only to specialists in the field of study of marine mammals but also to ichthyologists, oceanographers and those working on questions of the conservation and rational uliliza- tion of natural resources. The papers have been written by research workers who are conducting investigations on aquatic mammals in various basins in our country and in the oceans of the world. 3

SECTION I.

THE ECOLOGY AND DISTRIBUTION OF CETACEANS

Translator's note. Up to this page the pages in the original text were not numbered. On the subsequent pages of the translation the figures in the right-hand margin indicate the corresponding pages in the original text. UDC 599.5 B. A. Zenkovich

The fate of whales

All who are familiar with the organization and scope of the contemporary whaling industry, especially in the period of the last twenty years, cannot help being worried about the fate of the whales. The question of whether or not individual species of whales are threatened by complete extinction is now no longer a question that gives rise to doubts during the course of the last ten years, already after the Second World War, two species of whales - the blue whale (Balaenoptera musculus L) and the humpback or long-flippered whale (Magaptera nodosa Bonn) - have been almost completely exterminated everywhere. From the history of the whaling industry it is known that the smooth or right whales of the subfamily Balaeninae, which do not sink after death, were exterminated by the whalers of the sailing fleet already in the last century, and the whaling was then conducted with row boats and hand harpoons. This primitive technique was found to be sufficient to completely exterminate several species of slowly swimming and very fat-bearing right whales in both the Northern as well as the Southern hemispheres. By the seventies of the last century these same whalers had so decimated itxx numerous stocksof sperm whales (Physeter catodon L) that their commercial exploitation came to a halt, as it had become unprofitable. Untouched remained only the stocks of rorquals (Balaeno- pterinae), which sink after death, for which reason their 5 commercial explitation could-commence only after the invention by Svend Foyn in 1968 of the harpoon gun, which fired a harpoon with a grenade at its end, and of the compressor for in- flating the body of the whale with compressed air. Commercial exploitation of these whales has already been conducted for a hundred years. As is known, the contemporary rorqual whaling industry began off the coast of Norway, the homeland of the inventor of the harpoon gun, in the North Atlantic, where the first 30 whales were killed. It should be noted that the first of the rorquals were the blue whales, the largest of this subfamily. In order to represent the situation with respect to the whales more clearly, we will divide the whole of the

World's oceans into 4 whaling regions: 1. The North Atlantic

- from the tropics to the polar regions inclusively; 2. The North Pacific - the samet 3. The Antarctic - to the south of 4.0° latitude S. and up to the zone of impassable icet ^• The Southern hemisphere without the Antarctic. These extensive regions have their own particular subregions and sectors but we will not be speaking of these. N o r t h A t l a n t i c . As has already been mentioned the commercial whaling for rorquals was started off the coast

of Norway and then spread throughout the whole of the North

Atlantic, and in almost all suitable places there were organized shore stations, at which the carcasses of the whales were dressed. We will consider the results of the industry and to some degree the results of whale investigations in this region, paying attention to each-of the commercial species. 6

B l u e w h a 1 e s. In all from the start of the whaling in 1868 up to 1967 inclusively there were caught 7867 blue yhales, but only 651 animals were accurately measured and examined, including 377 males (57.9%) and 274 females

(4-2.1% ) * The largest whale had a length of 2804. cm and this was a femâle. The largest male had a length of 2620 cm.

Among the measured whales, 312 or 4•7.9% were found to be

sexually immature. The average length fluctuated within the

limits of 1950 - 2234• cm. Beginning in 1960 a ban on the

catch of blue whales was introduced in the North Atlantic, but up to the present time throughout this entire extensive.

area of water these whales have been encountered extremely

rarely if they have been encountered at all. There exist

fears that this measure.was belated and that the stock of

whales has been -campieté.lg killed off. It may be said with

confidence that in this region the stock of blue whales was

not numerous. It is a remarkable fact that the blue whales in this region approached close to the coasts and were killed

off by shore-based fl6ets. Fin whales (Balaenontera physalus 1).

During this hundred year period there were caught here no less than 57 280 fin whales, but measurements and examinations of these did not commence until 1930. Therefore we have at our.

disposal information on the measurements of only 18 327 fin

whales, including 9135 males (4-9.8%) and 9192 females (50-2%)- Out of this number 6793 or 37•0% were found to be sexually immature. The average length of the fin whales fluctuated within the limits of 1786 - 1900 cm; the largest males had 7 a length of 2285 cm and the females - 2386 cm. In recent seasons the number of sexually immature whales in the industry has reached up to 50.0%, with a catch of 790 - 1014 head. The stock is on the border of depletion an this is the most numerous species of whale for this region. Humpback whales. In all, from the start of the whaling here, there have been caught 3960 humpback whales and, - practically speaking, these have been completely exterminated. Apparently the population of humpbacks in the North Atlantic was very small and their biological characteristics permitted the whalers to completely exterminate this stock before the introduction of the belated ban on their catch. Since 1930 there have been measured 165 humpbacks in all, including 89 males (54.5%) and 76 females (45.5%). The largest males had a length of 1768 cm, and the females - 1707 cm. Let us remind ourselves that the female hunpbacks like all of the rorquals, are markedly larger than the males, and that therefore the catching of such a large male is a rare phenomenon. Among the measured humpbacks 64 or 38.8% were sexually immature. In 1967, in spite of the general ban, 4 female humpbacks were caught off the coast of Greenland and there were no mentions of a finding of embryos. Apparently they had not found partners. Let us remember that for the needs of the local population it is permitted to catch whales of any species and size. It may be thought that these were the last humpback whales. Let us note also that in the course of the last ten years before the introduction of the ban the humpback whales were caught only in ones or twos during the season, and nevertheless they were caught. 8

Sei wha les (Balaenontera borealis Les). Altogether there were caught 10 688 sei whales but only 1978 were measured, including 849 males (42.9%) and 1129 females (57.1%). The largest males had a length of 1585 cm and the females - 1615 cm. The average length fluctuated within the limits of 1308 - 1451 cm. Among the measured whales 976 or 119.3% were sexually immature. Apparently the population of sei whales in this region is also very small, but about half of the whales that were caught had never produced any progeny. Sperm whales. In the main whaling regions of the North Atlantic only the surplus large males in the herd are caught. According to the information that is available to us, in these places during the last 100 years there have been caught no less than 4819 males and 3989 have been measured. The average length of these sperm whales ranged from 1446 to 1620 cm; in the last 10 years there has been noted an average length of always more than 1500 cm and at the same time the largest individuals had a length of 1890 cm, while the smallest had a length of 1158 cm. Off the coast of Spain there have been caught 2984 sperm whales but the lengths and sex of these are unknown. Off the Azores and the Island of briadeira there have been caught 18 722 sperm whales, including more than 30% females and a no smaller number of small males from mixed herds; but up to 30% large males were also caught here, and the largest of these had a length of 1800 cm. In Table 1 are shown the results of the whaling industry in the North Atlantic from 1868 until 1967 inclusively. 9

Table 1. Catches of whales in the North Atlantic for the period 1868 - 1967.

Tanna 1 RoGhttia Rims B .CeBepHoil Amairrne aa. 1868-1967 rr.

A 13 .ffium eMMTUX KUTOB rIepnoju Poftomil Twomucna 6e.3 Bcero Whaling region cime cpmmanbt rop6atol cerlar.m a Total HopBerim 1868-1967 2062 15843 1127 6082 1331 6203 32648 2 Fienailemyt 1883-1967 2506 6389 219 988 1555 . 13365 25022 3 Iiblo(Paynxiem 1898-1967 1302 10273 1189 189 427 1895 15275 • • 4 (13apepénire ocTpona 1894-1967 102 5428 48 624- 675 5832 « 12709 5 3anaAlian l'pelmatuust 1926-1967 39 581 104 8 141 2 875 • re6pitacKne oupona 1904-1929 518 6528 63 2.285 .135 125 9654 11IoTealuuni-1-14p.rialuitsi • ,apyrue paiionm CeBepitoir 1868-1967 1335 5189 492 383 555 2684 10538 ATZWITIWII . 8 11o6epe.whe 11crtamili 1921-1967 2 6646 129 2984 952 10713 O flopTyramm (A3opctale H gpyrite 1910-1967 1 403 718 18722 1906 21750 7 ocTpoBa)

Been Total 7867 57280 3960 10688 26525 32864 39184

A - Periods of whaling B - Species of whales caught a - blue whales b - fin whales c - humpback whales d - sei whales

e - sperm whales f - no indication of species

1 - Norway 2 - Iceland ) - Newfoundland 4 - Faeroes Islands 5 - West Greenland 6 - Hebrides Islands, Scotland - Ireland 7 - Other regions of the North Atlantic 8 - Coast of Spain 9 - Portugal (Azores and other islands)

Altogether there were caught here no less than 139184 whales, which comprises 6.63% of the world catch. 10

North Pacific. According to the statistics which are available to us, the whaling with harpoon guns and correspondingly equipped vessels began here in 1900. In the northern part of the Pacific Ocean there were caught the sanie rorquals as in the North Atlantic, but, in addition, over the course of several seasons there appeared in the whaling catch the Pacific gray whales (Eschrichtius gaof_ibl ms Erxl), which for the present are known to be endemics of this region« The catch is characterized by the following datas Blue whales Altogether from the beginning of the whaling up to 1967 there were caught no less than 8585 blue whales - almost as many as in the North Atlantic. Information on the measurements is available from 19301 according to these data a total of 2588 blue whales were measured, including 1423 males (55.0%) and 1165 (45.0%) females. The largest whales attained lengths of: males - 2682 cm and females - 2713 cm. The average length in any year ranged from 2000 - 2400 cm. Among those measured, 1206 whales were sexually immature; this is 46.6%. It should be stated that in the last seasons before the ban the catch of sexually immature whales comprised 55-67%, 11 which is indicative of an almost complete extermination of this species in the North Pacific. Apparently it may be said that in this enormous region the population of blue whales was extremely small, since encounters with these in recent years have been very rare. From 1965 here also there was introduced a ban on catching blue whales, but only for 5 years. The ban on catching blue whales in this region should be extended for a prolonged period. 11

Fin whales. As in the other regions of the oceans of the world, the fin whales in this region are the most numerous species. During the period from 1900 to 1967 there were caught here no less than 71101 fin whales, though only 39770, or 56.2% of the total caught, were measured. Among these there were 20230 males (50.86%) and 19540 females (49.14%). The average length in any year fluctuated within the limits of 1774 - 1966 cm. Let us remember that the fin whales of the Northern hemisphere are somewhat smaller than their ,southern kin and the majority of them become sexually mature on attaining a length of 1800 cm. Among the measured whales there were 12 992sexually immature individuals, or 32.6%. In the last three seasons the number of sexually immature whales in the catch has attained levels of 32.6 - The largest males had a length of 2347 cm and females - 2500 cm. It was noted that in recent seasons encounters with fin whales have become considerably rarer than 5-7 years ago. It may be concluded that the stock is being intensively exterminated and that a strict regulation of the industry is necessary, with the establishment of a limit of considerably less than 1000 head per season, and moreover only sexually mature animals should be caught. On some of the large fin whales,which were caught in the south-eastern part of the Eronotskiy Zany (bay) and further to the south in the ocean, there were found the external parasites Penella antarctica Quidor, the same ones that occur on the fin whales in the Southern hemisphere. 12

Humpback whales. These whales have been almost completely if not completely exterminated in the sixties, i.e. in our time. The stocks of these whales (as previously, we divide these into the American and Asiatic stocks) were not numerous, but nevertheless the American population had the greater numbers. The Asiatic population virtually ceased to exist at the end of the fifties, having been killed off near the island of Okinawa by American whalers. The more numerous American population was intensively exterminated during the coûrse of 1958 - 1965 when from 280 to 2300 whales per season were caught (in 1963 - 2339:). In total, from the beginning of the whaling up to 1965, the year of the ban, there were caught no less than 24346 humpbacks, but only 8114 whales were measured, or 33.3%. Among those measured there were 4265 males (52.6%) and 3849 females (47.4%). Of these, 3702 or 45.6% were sexually immature animals. The average length of the humpbacks ranged within the limits of 1163 - 1330 cm. The largest males had a length of 1768 cm and females - 1798 cm. The external parasites of the North Pacific humpbacks, 12 the "whale lice" Paracvamus booris, are similar to the parasites of these whales in the Australian and New Zealand stocks, which have also been exterminated during the last few years. The Asiatic stock of humpbacks was exterminated completely by shore-based whalers, while the American stock - by pelagic fleets. Sei whales. The sel whales or "ivasi" whales (Japan) have for a long time, since 1910, been the object of the Japanese summer shore-based whaling industry. They have 13 also been caught in other places in the northern part of the Pacific Ocean, but in small numbers, while off the coast of Japan they have been caught in hundreds. Oomparitively large whaling for sei whales began with the organization of the considerable, for this part of the world's oceans, pelagic whaling industry at the end of the fifties and the beginning of the sixties. Whaling for these has increased considerably after the extermination of the humpbacks and the decrease in the population numbers of the fin whales. During the period from 1900 till 1967 there were caught 511.875 sei whales, and during only the last ten years - no less than 27747 or more than 50% of the catch of the entire many years of whaling. Altogether 37780 sel whales have been measured, including 19940 (52.7%) males and 17840 (47.3%) females. Out of these, 18232 whales or 48.25% were sexually immature, never having produced progeny. The average length of the sei whales ranged from 1290 to 1384 cm; the largest male had a length of 2042 cm and the largest female - 1890 cm (two specimens in all). Already at the present time the sei whales are being killed off, the last species of the large rorquals. The whaling for these in the North Pacific is proceeding at an increasing rate and during the 1967 season 6115 of these whales were caught, a figure which is unprecedented for this region. Urgent measures are necessary for the organization of a proper exploitation of this stock. We note also that the pelagic fleet, and primarily the Japanese fleet, has directed all of its efforts towards the catch of the American stock of sel whales, while the Asiatic stock, which is being exploited àhlY ê by the shore-based fleet of Japan, is not undergoing suCh whaling pressure. It may be thought, therefore, that the numbers of the Asiatic stock of sel whales has not suffered particularly great changes. Of the 6115 sei whales which were caught in 1967, 5558 or 90% were taken from the American Stock, and moreover the Japanese pelagic fleet alone took 3474 whales: Sperm whales. The whaling for sperm whales, and primarily the whaling by the pelagic fleet, has increased to such an extent in this region that it is impossible that one not be alarmed about the state of the stocks. From 1900 till 1967 there - have been caught no less than 171400 sperm whales, but during only the last 10 years 101 936 of these whales have been caught, or more than 59.5% of the entire catch over the many years of the whaling. To this it should be added that a considerable number of sperm whales have begun to bé •

caught in the warm zone from mixed herds, i.e. females and young.males, and moreover among the females a considerable number were pregnant. On more than one occassion it has been said that à rational whaling for sperm whales can be organized only in the cold zone of the oceans, into which move the surplus ail& mainly large males of the stock. On the other hand the whaling for females can only be selective and, moreover, It should be organized in such a way that at approximately at 5 year inter vals, but not more frequently, the flotillas would move into the warm zone of the ocean, where one finds only mixed herds, and there catch only large (of no lesser length than 1250 cm) 15 females which are easily distinguished from the young males that are generally found in these same herds. At our disposal we have measurements from 145 4.00 sperm whales, which were mainly caught in the years after the war.

Among these are 117 887 males (77 v 8%o) and 27 513 females (22.2%).

It is known to us, however, that the Japanese shore stations have in recent years been catching 50% and more females. The percentage of females in the catch of the pelagic fleet is also increasing. It is inevitable that the overexploitation will also have an effect here in the very near future. The largest measured sperm whales had a length of more than1900 cm, and one of these, caught off the Kuril Islands, was 204•2 cm in length. Such sperm whales, however, are encountered extremely rarely. The average length of the males ranged from 1235 to 1315 cm, and of the females - from 1014, to 1122 cm. It will be recalled that the pelagic fleet has the right to catch sperm whales the length of which is not less than 1160 cm, while the shore fleet may catch those over 1070 cm. To this it should be added that the weight of the males is 30 -40 tons, while that of the largest females is

12 - 13 tons. Correspondingly also the yield of the oil production from males, caught in the.cold zone, comprises 7 - 12 tons, while that from the females is 2 - 3 tons.

P a e i f i c g r e y w h a l e s. Commercial whaling

for these whales has been banned since after the war, though

local inhabitants, the aborigines of Chukotka and Alaska,have

the right to catch them, as also all other whales. On our

Chukotka coast they are caught according to an established 16 lim3.t, which must be strictly observed. These are typically coastal whales, which in the summer move into the bays and lagoons of the Land of the Koryaks and Chukotka. They attain a length of 1500 cm; the females are larger than the males. As a result of the ban the American stock of grey whales has become gradually reestablished and at the present time it numbers from 8 to 10 thousand head. The Asiatic or Korean stock of these whales was apparently -- exterminated to such an extent that already for several years we have not had any informàtion about encounters with these whales close to

Sakhalin and in the Shantar Sea, which were once their summer habitats. According to the statistical information, from 1900 to

1967 inclusively there were caught no less than 2568 grey whales. These statistics do not include data on the whaling conducted by the Chukchi and Eskimos in Chukotka and Alaska, who caught approximately the same number. During the course of recent years American scientists have caught 237 grey whales for scientific purposes in the places of their winter habitat off the coast of California and in the Gulf of California. We have presented the information on the commercial exploitation of whales in the northern part of the Pacific Ocean in Table 2. Altogether in this region there were caught no less than 342 854. whales, 16.3% of the world catch. How- ever during only the last 10 years here there were caught

163 031whales, almost half of the catch in this region over the many years of whaling. The extermination of such a considerable number of whales cannot but also have an effect on all 17

Table 2. Catches of whales in the North Pacific for the period 1900 - 1967.

• T a 6.9 it u a 2 Ro6bt4a Karon a Ccaeptiort IlawitbaKe 3a 1900-1967 rr.

A BITAbl kirrou Ommi Sum Countries mOeiu Muum mianotm nyrue Total a o d • USSR CCCP 887 15016 5215 7894 80668 1070 110750 Japan 51nom1a 2930 39756 3537 42690 82734 4687 176334 USA- =A— 4768 16329 15595 4293 7998 • 6687 55670 Canada Katia.aa* Total 1.3cero' 8585 71101 24347 54877 171400 12444** 342854

* ^ KIIT060e1-1. — 13 TOM Mic.rie 2568 Cept•IX TuttCoOifeaHcKuux liliT013 a 154 izaerosnizeix r.iatutuux Kura.

* - Including the catch of Norwegian whalers ** Including 2568 Pacific grey whales and 154 right whales. A - Species of whales a - blue whales b - fin whales c - humpback whales d - sel whales e - sperm whales f - others.

of the other commercial fauna of this region. The sperm whales, consumers of a tremendous number of cephalopod mollusks, have been exterminated to a considerable extent by the whaling of recent years, and it should be kept in mind that squids and octopuses are predators that destroy crabs and shrimps. The balance of nature of this region has been drastically disturbed during the last ten years and this will rapidly have an effect on the biological resources of the North Pacific, not only on the population numbers of crabs and shrimps but also of fishes. 18

We will now pass on to a consideration of the activity • of whalers in the Southern hemisphere. Southern hemisphere. Whaling for rorquals in the Southern hemisphere commenced in the season of 1904 in the Antarctic. In other places in this hemisphere (off the coast of Africa, South America, Australia and New Zealand) it commenced a little later, in 1908. However, while in the north the whaling was conducted with few exceptions almost uninterruptedly, in the Southern hemisphere, outside of the Antarctic, it was often interrupted for various reasons, including also the extermination of individual populations of whales (Gabon, Walvis Bay* ), while in some places it was interrupted for a long period of years and was sometimes never resumed for other reasons. We note also that during the initial period in this hemisphere the whaling was carried out all the year round. We have brought together the information on the commercial exploitation of whales in the Southern hemisphere in Table 3. We will consider these data, starting with the main whaling region of this hemisphere - the Antarctic. Antarctic. The commercial exploitation of whales in the individual whaling sectors of the Antarctic and its significance have been dealt with in several studies, the information being given up to 1965 inclusively. Therefore we only indicate here that in Antarctic waters alone up to 1967 there were caught 1289858 whales - 79.8% of the catch in the Southern hemisphere and 61.27% of the world catch over a period of a hundred years.

*Translator's note. Actually the Russian name "Uolfish-Bei° is a phonetic transcription of the old name - "Walfish Bay".

: ;15 , on co çk .7 -re ›•-• • e t•D 1 Y. 4N. 7...* ço re> r •• — C.0 •••••1 0 r> o o 0 cx

o 0 co OVelltni "0 7 YY-3 -006 NI 31 r C‘ , t7' nee 8 0 • •r2.1 61 CD • a."' • Y-Y an •"' ô• — - 0 . 7., 0 f 3 I lOt

a 7. H. .1-. CY • C') yz) I. I -3 72) 0 L9 • — CO Co *. --I • 0 o rt) I •••••.1 0 e- 0 O• . ;) 0 0 0 7:3 Fe' 0 F3. ;IC L' ( y , -4 -0 rz= o • "I 0 B 0 • .72. W . II o d

d ( F. 7D 4.• rc., 0H — • ta 4

OCI H C H.. O 4 CI 4 o „F. CO 211 o 4 W W •o r) W o :71 4 oma 0 mrew :1 4 4. rn E" 5. #1 4" o 4 ,1 XX ■ ?F 17' - •-• .< 0HO UHUDN 9 9 B n) 0

-4

•Table 3 • The whaling industry in the Southern hemisphere in Ta6atina 3 the 'period from 1904 to 1967. Kirro6oeunet npamucen 8 . 101,KHom no.nywaprtx 3a 1904-1967 rr.

Periods •Species of BII1Ibt .Z061rIblIC 1:11:09 whales caught; of nepnome Pa ou IIp O4blCa blue fin nump- sei sperm lotherS Bcero ..m q.yynyeazby rop6amly çey:4i33.1by ICJW=CrI ld APYMIC Régions' whaling backs Total

Antarctic ARTapliniKa 1904-1967 331145 673982 68287 -99652 106313 10479 1289858 Africa Ainmixa 1908-1967 13156 32250 40505 16688 47865 14792 ' 165256 Australia Ancrimun. .1910-1967 36 11 37177 8 5455 7 42694 New Zealand HoBan 3e.ualvex 1930-1967 5 1 3653 • 24 265 3948 Coast of flo6epe)Kbe Ilium • 1910-1967 5040 7509 2187 1367 90456 1350 107909 Peru lIepy • Chile - • Brazil Bpaamest 1911-1914 2 86 • 1233 4911 345 146 6723 1947-1967

Total Bcero 349384 713839 153042 122650 250699 26774 -1616388 20

In these waters were caught the largest blue whales and the largest fin whales. Here also their average dimensions are the highest. All of this has been discussed before (Zen- kovich, 1965 - 1969). It is necessary to recall once more that in the Antarctic waters there have been almost completely exterminated the once numerous stocks of blue and humpback whales, and moreover this has occurred in the last ten years. Nevertheless the commercial exploitation of fin whales is continuing here, although it is clear to all that their numbers have decreased severalfold (the remaining stocks are about 20% of the initial numbers). In these waters in a record short period, literally during the course of the last 5 years, there has been a decrease in the population numbers of the last stock of rorquals, of the sei whales. Only five years ago we could say that the stock of sei whales had been little affected by the whaling. However during this time there were caught 69387 sei whales, with an initial population of these, according to our calculations, of 75 thousand head. Whaling in Antarctic waters may be carried out only from the 12th of December up to the 7th of April, but during this short period the flotillas succeed in fulfilling their plans. It is necessary to add that in the Antarctic waters at high latitudes there are generally found very large old whales, which approach up to the edge of the ice and even up to the Antarctic continent, where they are frequently observed both in the open spaces between belts of pack ice as well as off the landfast ice. 21 •

We have proposed the hypothesis that the migration of whales into the cold waters of both hemispheres and their ten- dency to approach close up to the ice are not connected with the search for food, which is quite sufficient within the warm zone, but with the necessity for getting rid of external and internal parasites and, consequently, these migrations have a sanitation-measure character (Zenkovich, 1965). We already have at our disposal data which confirms this hypothesis. We will now pass on to consider the situation with respect to the whales in other geographical places in the Southern hemisphere. Africa. Off the coast of Africa whaling started in 1908, and at one time or another it was carried out along the whole of the Atlantic coast and on the eastern coast, washed by the Indian Ocean. From the equator up to the Capes of Good Hope and Agulhas, along both sides of Africa, there were situated shore stations and sometimes floating bases (pelagic flotillas) operated. Included in the zone of their activity were also the waters which wash the island of Madagascar. In the period up to 196 7 inclusively there were caught here no less than 165 256 whales, or 10.22% of the number caught in the Southern hemisphere. It was not until the middle of the 1 7 forties that rules were introduced here which regulated the whaling. Blue whales. There have been caught no less than 13 156blue whales and only 802 of these were measured, including 396 males (46.1%) and 416 females (53.9%). A considerable portion of the blue whales, more than 12 thousand, were caught 22 prior to the introduction of the regulations concerning the measurement of whales. It should be noted that these whales were caught by the hundreds every season in the region of Walvis Bay and off Angola. During the period from 1923 to 1928 in Walvis Bay (on our maps "bukhta Kitovaya" = "Whale Bay") there were caught 1735 blue whales, and among these was the famous blue giant-whale from which there were obtained 55 tons of the oil product alone. This was a unique case in whaling experience. Normally a blue whale of average size produces 20 tons of the oil product at a weight of 100 tons. Off the coast of East Africa (Natal) in the Indian Ocean there were caught 3152 blue whales, while off the west coast in the South Atlan- tic - 7080. A striking fact is that in all of the places listed there were caught mainly sexually immature blue whales. The average length of the whales caught ranged from 1976 to 2208 cm, and this is the length of sexually immature animals. The largest males had a length of 2620 cm and females - 2713 cm. Fin whales. During this same period there were caught here no less than 32250 fin whales, among these no less than 21 360 along the Indian Ocean coast and no less than 10 790 off the Atlantic coast (Saldanha Bay, Cape Coast, Walvis Bay, Angola and Congo). Measurements on these whales are available from 1946. Up to 1967 there were measured: on the Atlantic coast - 2658 fin whales, including 1339 males (50.3%) and 1319 females (49.7%). The average length ranged from 1705 - 1902 cm, the largest males had a length of 2347 cm and females - 2438 cm. 2017 or 75.8% of the whales were sexually immature. 23

Along the Indian Ocean coast there were caught 21 360 fin whales and 10300 were measured, including 5477 males (53.2%) and 4823 females (46.8%). The average length fluctuated within the limits of 1685 - 1890 cm, the largest male had a length of 2345 cm and female - 2435 cm. Two thirds of the whales, 6860, were sexually immature. From these data it is evident that the coastal whaling for a long time has produced mainly young sexually immature fin whales. Humpback whales. Altogether in these coastal regions, including the island of Madagascar, there were caught no less than 37598 humpbacks, though only 12273 were measured, including 6734 males (54.8%) and 5539 females. The average length of these ranged from 1128 to 1268 cm. The largest whales had a length of: male - 1707 cm and female - 1950 cm. This was the largest female humpback whale which has ever , been measured in the oceans of the world. Among the measured humpbacks, 3571 or 45.7% were found to be sexually immature. Taking into consideration the characteristics of the biology of the humpback whales and their ad- herence to coastal regions, one should not be surprised by the 18 fact that both populations off the coasts of Africa have become extinct. It will be recalled that at the start of this whaling industry observation posts were organized on many of the promi- nent headlands in South Africa. These posts counted more than 12 thousand of these whales on only the Atlantic coast during migrations to the north. Approximately the same number within the limits of visibility also passed to the south. However off Gabon (Congo) alone there were caught 15448 humpbacks in the winter months of the Southern hemisphere, when the whales 24 approached its shores to give birth and mate. Quite close by,. off Angola, there were caught no less than 6595 humpbacks, and altogether along the Atlantic coast - 23 057• About the sanie situation occurred on the coast washed by the Indian Ocean. Here off Natal there were caught no fewer than 8348 whales, a little further to the north - 3218,and off the island of

Madagascar - 2975 humpbacks. Off the coasts of the Congo and off Madagascar pelagic flotillas operated. Thus, the whales were exterminated both off the coast and further out to sea, where the whalers of the shore stations did not always get to.

S e i w h a 1 e s Altogether there were here caught no fewer than 16 688 sei whales, though 11 878 were measured and examined, including 5374.males (4-5.2J) and 6504 females (54.8%). This^unfortunately, is the only example where a majority of females were caught. The average length of the sei whales ranged from 1335 to 14.12 cm, the largest male had a length of 1737 cm and female - 1798 cm. There were 5742 or

4.8.3% sexually immature whales. No fewer than 10 909 whales were caught along the At- lantic coast and about 6 thousand on the Indian Ocean coast. At the present time these same populations of sei whales are being exploited by the pelagic Antarctic fleet and consequently in the very near future their numbers will fall abrubtly.

S p e r m w h a l e s. Altogether off the South African coast there were caught no fewer than 47 865 sperm whales., of these there were more than 36 thousand in the Indian Ocean subregion and more than 11 thousand in the Atlantic. While in the first years only a little more than 30% females were caught, recently the numbers of females in the catch in some years has 25 exceeded 50% and at the sanie time a considerable number of young males have been caught from mixed herds. To this it should be added that the pelagic flotillas on their way to the Antarctic also often conduct whaling operations close to the African coast, exploiting these same stocks. The average length of the males caught- here not long ago ranged from 1255 to 1358 cm, but in recent seasons this has been a range of 1175 to 1208 cm. More than 60% of the males caught and all of the females have a length of less than 1200 cm. Apparently the old large females have been killed off, as have the large males. The whaling is continuing.

Bry de 's whales. These not often encountered whales have been caught in the number of 1563 head, and 1508 of these were caught in the Atlantic region. Apparently, these whales when caught in the Indian Ocean subregion were identi- fied as sei whales; it is difficult to imagine that they were not caught in the Indian Ocean, where our research ships, during passages through these waters, fairly frequently observed Bryde's whales, from the Gulf of Aden and further to the south. The average length was about 1300 cm, the maximal length - a little more than 1500 cm. The whaling operations, however, catch even eight-meter calves. Such is the situation in one of the most commercially exploited regions in the Southern hemisphere, excluding the Antarctic. Australia. According to the information which we have at our disposal, in the waters off Australia there were caught no fewer than 42107 whales, and moreover in the the course of several years it has been exclusively humpback 26 whales, of which 37 177 head were caught here, that have comprised the basis of the whaling. If one does_not take into account the small whaling for sperm whales, then all of the other whales make up a rarely occurring incidental catch. ]:n- cluded in this incidental catch are 36 blue whales,.11 fin whales, 7 sei whales and 7 Bryde's whales. During the first years the whaling off the coast of Australia was carried out by pelagic flotillas, which caught exclusively the humpback whales. The activity of these flotillas led to a considerable drop in the population numbers of the humpbacks and from 1938 until 194.6 there was no whaling in these waters. From 1947 thereVere organized up to 5 shore stations, which began whaling, and once more exclusively for humpback whales, according to a precisely established limit.

However,after fifteen years of the whaling; the stocks of humpbacks had been exterminated to such an extent that during the last season in 1963 only 87 whales of this species could be caught and the whaling had to be stopped, by the introduction of a complete ban on the catch in the whole Southern hemisphere.

Humpback whales. It has already been stated above that there were caught here no fewer than 33177 humpbacks, although only 27 838 were measured and examined, inclu-

ding 17317 males (62.0%) and 10521 females (38-0%) - Conside- rably more males were caught and this was affected by the spe-

cific features of the regions the mating and birth of the young

occur here. According to the whaling regulations females with calves cannot be' disturbed, but according to these same regulations there could be caught a considerable number of sexually immature animals, of which there were caught 12784 or more than 45% of the total number. Of course, such whaling could not continue for long. The largest males had a length of 1554 cm and females - 1585 cm. Their average length ranged from 1143 to 1256 cm. Sperm whales. The development of the commercial exploitation of sperm whales here is connected with the fall in the population numbers of humpbacks and then with their complete disappearance. During recent years there have been caught 4869 sperm whales, almost all of these being large males, from which is obtained 7 tons of oil product. Females are rarely caught, although mixed herds constantly occur close to the Australian coast. New Zealand. Closely connected with the Australian whaling industry is the commercial exploitation of whales off the coast of New Zealand. Here also there were mainly exploited the humpback whales, of which no fewer than 3653 were caught, with a total catch of 3948 head. Here also the whaling was stopped as a result of the disappearance of the humpback whales in 1964 and attempts were also made to change over to a commercial exploitation of the sperm whales but for various reasons this too.was closed down completely in 1965. We will consider the few data on the humpback whaling off these coasts. Humpback whales • The whaling for these was carried out from small motor boats with the aid of a small calibre harpoon gun close to the shores, to which the humpbacks generally approached in groups of ton or more. This characteristic of the humpbacks was exploited so that they could be caught with the aid of wire nets. This primitive technique, 28

(motor boat and net) allowed 3653 humpback whales to be caught, o. starting from 1930. The measurement and examination of these began to be carried out only from 1949. Altogether 2161 whales were examined, including 1297 males (60%) and 864 females (40%). More males were caught for the same reasons as off the Austra- lian coasts. The largest males had a length of 1524 cm and females - 1554 cm. The average length ranged from 1190 to 1238 cm. Sperm whales, Almost exclusively males were caught; during the last two years there were caught 2 •8 sperm whales, including only 8 femalesb The largest males had a length of 1676 cm and females - 1190 cm. The average length of the males ranged from 1385 to 1425 cm. Other whales . During these years there were caught here 5 blue whales, 1 fin whale and 24 sel whales. As has already been mentioned, at the present time the whaling in this region has been completely stopped. Peru and Chile. We will pass on to a consideration of another extensive whaling subregion, situated off the western coast of South America* the Peru-Chile subregion. Up until 1937 all of the data on the whaling in this subregion were given combined together, and therefore we have to continue to combine these, although there is available information on the catch of the Peruvian and Chilean whalers separately, commencing from 1937. In this part of the Pacific Ocean there were caught fie no fewer than 107909 whales; this is 6.67% of the number of whales caught in the Southern hemisphere. Chile and Peru did 29

not sign the convention on the regulation of the whaling industry and do not subordinate themselves to the regulations for conducting whaling. Here whales of all species and of any size are caught. The rejection of the convention is in part explained by the fact that whale meat, including also the meat of sperm whales, is used as food by the population. Here are caught all of the species of whales which are found in the Southern hemisphere. We will consider those data that are available on the different species of whales. Blue whales . Altogether there were caught 5040 blue whales, though only 1800 were measured, including 874 males (48%) and 926 (52%) females. The largest whales had a length 21 ofs males - 2530 cm and females - 2713 cm. The average length ranged from 2098 to 2286 cm. Among these there were 1414 or 78.5% sexually immature individuals. It is mainly the young animals which move up into the coastal regions. Fin whales. Altogether 7509 fin whales were caught, though only 3002 were measured, including 1521 males (50.7%) and 1481 females (49.3%). The largest fin whales had a length oft males - 2225 cm and females - 2347 cm. The percentage of sexually immature whales ranged from 45 to 100%. In rare years sexually mature fin whales were caught here. Humpback whales. Altogether in the local waters there were caught 2187 humpbacks but, unfortunately, only 42 were measured, including 34 males and 8 females. The largest male had a length of 1646 cm, while the largest female was 1676 cm in length. The average length ranged from 1128 to 1433 cm. 30

S ei whales. Altogether 1367 sei whales were caught, though 961 were measured, including 362 males (37.6%) and 599 females (62.4e). The average length ranged from 1153 to 1380 cm. The largest male had a length of 1615 cm and female - 1860 cm. More than 50% of the measured whales were sexually immature.

S perm whales. Sperm whales are the most numerous species in these waters. These were hunted here even during the days of the sailing fleet, but the contemporary whaling opened up in 1912. Up until 1967 inclusively there were caught here no fewer than 90456 sperm whales, though 56308 were measured, including 314.899 males (61.9%) and 21409 females (38.1%). The males approach closer to the shore in greater numbers, while the mixed herds and separate herds of males keep themselves out further to sea. The average length of the males ranged from 1107 to 1520 cm and of the females - from 926 to 1100 cm. The largest males had a length of 1890 cm and the largest females - 1311 cm (very rare females attain such a length). Such are the results of the whaling off the PacifiC coast of South America. We will consider the activity of whalers off the eastern Atlantic coast of South America. B razil • Off the coast of Brazil the whaling industry commenced in 1911 but it wasdiscontinued in 1915. It was not resumed again until 1947. In these waters there are found all of the whales of the Southern hemisphere, but during the entire period of the industry here there were caught only 6823 whales. Only two blue whales were caught: one male 2134 cm in length and a smaller female which was 2073 cm long. 31

Fin whales. Only 86 fin whales were caught here, all of which were measured. Among these there were 44 males and 42 females. The largest male had a length of 2286 cm and female - also 2286 cm. The average length ranged from 1862 to 1996 cm. Among these there were 52 (60.0%) sexually immature animals. Humpback whales. At the very beginning of the whaling off the shores of Brazil there were caught exclusively humpbacks, and during the first four seasons (1911 - 1914) there were caught 1113 of these whales. During the entire period of the whaling here there were caught no fewer than 1333 humpbacks. Apparently that small population which moved in close to the Brazilian coast . was killed off during the very first years of the industry, since during the post-war years there have been caught here from 5 to 28 humpbacks in a season, though most frequently about ten. Nevertheless we have measurements of 156 humpbacks that were caught in these waters, including 81 males (51.9%) and 75 females (48.1%). The average length ranged from 1198 to 1370 cm. The largest males had a length of 1615 cm, and the largest females were of the sanie of these whales or 39.1% were found to be sexually length. 69 immature. Se i whales. Altogether 4911 sei whales were caught, though 4620 were measured, including 2679 males (almost 58%) and 1941 females (about 42%). The average length ranged from 1388 to 1600 cm; the largest males had a length of 1951 cm and females - 1800 cm. It should be noted that the percentage of sexually immature sei whales here was very small: 10 - 12%. 32

Sperm whales. Altogether there were caught 345 sperm whales and almost all of these were measured - 341, including 197 males (57%) and 144 females (43%). The average length of the males ranged from 1150 to 1420 cm and of the females from 1078 to 1245 cm. The largest males had a length of 1707 cm and females - 1340 cm. The herds of sperm whales move in close to this coastline (see Table 3). Such are the results of the commercial exploitation of whales in the Southern hemisphere. We have described very briefly the development of the industry in all of the main whaling regions and may now speak about what this enormous and little thought-out catch has led to. Contemporary whaling technique, modernized during the last ten years, including high-tonnage (of tens of thousands of tons) floating bases with slipways for the hoisting of the carcasses, capable of processing more than 100 whales daily, and the fast whalecatchers, equipped with harpoon guns, com- pressors and various searching apparatus, gives practically no opportunity for even one whale to escape the chase. While during the hundred year period from 1868 to 1967 inclusively there were caught 2 105 246 whales in all of the oceans of the world, in the period from 1930 to 1967 alone there were caught 1631254 whales, or 77.48%. Individual species of whales, as has already been stated, have been intensively exterminated (Table )i). Thus, the blue whales, which in the 1930/31 season comprised 68.7% of the world catch and occupied first place, already by 1940 had moved to second place - 30.6%, bY 1955 - 4.5%, and by 1967 - 0.13%. In all 365 870 blue whales were caught in this hundred year period. :! 02 0-■ 2e5 :1;1 • . o n ""5 r-. "-• • X ' iND 0 • oa (1) - te. 3_4 01 = 3-4 r.) 00 0 Ls -; co- - Cr. 2 CD • >"1 • r> ro tà• 0 ° 01 E .1=1 g O r reM0 5: 0-1 CD 0% 0t Cr 0% •••••• 01 ro - o ir 3 .4.1 """•• n '-o b" co te 2,3 (-D L, G-• CD -a cm, r-p ez - o M 0 .0 ° cc PD tz, 0 Ca ro o -0) 0 ■ OD • . o -o c 01 00 00(1 Fa. io" n CD ro 0.) 0 _ 0 I 0. r. to ^0 CI 0 0 crt ▪ "P r7. = rD • r) ..-- O CD t:2 I c, r) .- ^ P.3 - • •-,› CD ( 0 9 ▪ to P-." t.. z E3 0.1 CZ :.). 0 • rD 'e • 0 CD OD 0 t 1:1 0 9 os 0-s s >1 • _7 14 -3 CD - op r) r.-- r; •-• CD >I: -0 0 '"= .:<«7 I 0 n • - s rD r•D 0., cc: CD :e .1" r.-. 0 .e 0• • 0 g" Cz' • - • . à :24 OD 0 M

Table 4 •

The eatch of whales in the oceans of the world. Ta6mitua 4 ,Uo6beta. KTITOE n rtiltposom- oKeaxe

Species B st e b! Ce30Ing blue fin hump- sei sperm epy Pre 6 en Bcero ›a sons clause . % 4/11180.1b: tq rop6atrst % canning e4 sca tua eon: e4 Pc33 nun ei Total whales whales backs whales 4hales =it • 1 2 3 4 5 6 7 8 9 IC 11 12 13 14

1868-1930 124612 26,2 158332 33,4 89475 • 18,9 26536 5,6 7879 1,7 67155* 14,2 473989 1930/31 29649 68,7 11367 26,3 924 2,1 652 1,5 517 1,2 21 - 43130 ' t 1931/32 6705 51,6 4158 32.0 635 4,9 492 3,8 632 4,9 366 2,8 12988 1932/33 19067 65,9 7089 24,5 .501 1,7 433 1,5 1234 4,3 583 2,0 28907 5 1933/34 17486 53,7 8731 26,8 2289 7,0 541 1,7 1847 5,7 1689 5,2 32536 1934/35 16834 42,8 14078 35,8 4088 10,4 962 . 2,4 2238 5,7 1111 2,8 39311 1935/36 18108 40,3 .12155 27,1 7776 17,3 823 1,8 4853 10,8 1153 2,6 44868 1936/37 14637 28,5 17637 34,4 9853 19,2 1236 2,4 7055 13,7 911 1,8 51379 1937/38 15035 27,4 29680 54,0 5125 9,3 929 1,7 3763 6,8 370 0,7 54902 1938/39 14152 30,9 22622 49,4 1393 3,0 815 1,8. 5511 12,0 1290 2,8 45783 1939/40 11560 30,6 19722 52,3 454 1,2 538 • 1,4 4671 12,4 764 2,0 . 37705 1940/41 5028 21,3 9150 38,7 2939 12,4 807 3,4 5641 23,9 73 0,3 23638 1941/42 . 81 1,0 2169 27,1 306 3,8 373 4,6 4957 61,8 128 0,1 8014 1942/43 151 1,8 18.09 21,6 288 3,4 506 6,0 5503 65,7 115 1,4 8372 • 1943/44 353 5,5 2204 34,2 282 4,4 989 15,3 2614 40,6 3 - 6445 1944/45 1111 18,8 2617 44,2 303 5,1 218 3,7 1669 28,2 1 - 5919 1945/46 3675 18,9 10934 56,7 495 2,5 747 3,8 3461 17,9 22 0,1 19384 * 43 Oç3i0131i014, 9TO - ropGamr x B Nexintiem tmene-tinuina.114 * These are mainly humpbacks, and in smaller numbers - fin whale's and sel whales. a. - others, with no indication of species. 0,;

Continuation of Table 4.

^1. ilpôAonlTcelilse ra6a.4

1 2 i S 1 4 S 6 7 I 8 9 I 10 11 12 13 ^ . . 14 194.,/47 ,;.. •;.3Ÿ820 9302 26,7 16495 47,4 290 1131 3,2 7546 21,7 5G 0,1 1947/43 7157 16,5 24028 55,4 515 1573 3,6 9850 22,7 259 0,6i 3382 1948/49 7781 17,7 21763 49,4 3395 1855 4,2 9016 20,5 192 0,4 ^ .: ^4002 1949/50 6313 14,0 22902 50,3 5063 2471 5,5 8219 18,2 125 : ^15093 1950/51 7278 13,0 22819 40,9 4352 3033 5,4 18281 32,7 49 0,1 55812 1951/52 5436 10,9 25605 51,4 4023 3123 6,3 11558 23,2 49 0,1 49794 1952/53 4218 9,4 25581 56,9 3328 2208 4,9 9577 21,3 51 0,1 449G3 1953/54 3009 5,6 31335 58,4 31;ï5 2491 4,6 13543 25,2 82 0,1 53615 1954/55 2495 4,5 32185 58,5 2713 1940 3,5 15593 28,3 115 0.2 55041 1955/56 1987 3,4 31496 54,2 :3880 2076 3,6 18590 32,0 33 58062 1956/57 1775 3,0 31626 53,6 3196 3138 5,3 19156 32,5 99 0,2 58990 1957/58 1995 3,1 31587 49,3 2923 5670 8,8 21846 34,1 54 0,1 64075 1958/59 1442 2,2 30942 48,1 5055 5539 8,6 21298 33,1 97 0,1 64373 1959/60 1465 2,3 30985 48,8 357G 7035 11,1 203-14 32,0 84 0,1 63489 1960/61 1987 3,0 31790 48,4- 2840 7785 11,8 21130 32,2 109 0,2 65641 19G1/62 1255 1,9 30178 45,7 '4436 8804 13,3 23316 35,3 101 0,1 66090 1962/63 1429 2,2 2191G 34,5 2758 9549 15,0 27858 43,8 69 0,1 63579 1963/64 372 • 0,6 19182 30,4 318 13690 21,7 29255 46,4 184 0,3 63001 1'.)6-1/G5 613 0; )-I 12317 19,0-1 452 25-153 39,35 255-18 19,5 297 0,46 6-16:;0 1965/GG 243 0,42 6832 11,9 59 23067 39,9 27311 . 47,`_> 262 0,45 5782•1 1966/67 70 0,13 6312 12,3 .1 18990 36,8 25921 50,2 266 0,51 51593 Total Bccro 365870 842512 181457 188218 4•?8801 78388 2105246

i ^ ••; -i 0 C1 W . = ,..C. ^ t ^ _^ ^^ n-3 n v ^ O ^ ^ n H ^Cr 0 Ô ^ r.., .,. "' 35

The humpback whales, which were being caught in thousands as late as the beginning of the sixties (in 1962/63 - 2758 head), have also been exterminated and in the total catch 25 during the 1967 season they were represented by 4 individuals. During this same hundred year period there were caught 181457 humpback whales. The commercial exploitation of the most numerous species everywhere, the fin whales, of which 814.2512 individuals were caught during the hundred year period, is continuing and from only 1930 until 1967 there were caught no fewer than 684.180 whales of this species, 81.2% of the entire catch of fin whales. As late as the fifties and the beginning of the sixties (1950 - 1962) they comprised 40 - 58.5% of the total catch, more than 30 thousand fin whales in a season. Their population numbers have fallen drastically everywhere. During the 1966/67 season the fin whales comprised 12.3% of the total whale catch. At the present time (1960 - 1967) there have been drawn into the whaling of the pelagic fleets the stocks of sei whales, a species which was previously caught only by some of the shore stations. While 188218 of these whales were caught during the hundred year period, in only the last ten years (from 1957) no fewer than 125 582 have been caught, or 77.6% of the total catch of these whales. During the last two seasons the catch of sei whales has comprised 36.8 - 39.9% of the total whale catch and their population numbers have decreased markedly both in the waters of the Southern hemisphere, especially in the Antarctic, as well as in the northern part of the Pacific ocean. 36

From the beginning of the fifties a greater and greater significance has been acquired by the commercial exploitation of sperm whales, which in 1950 already comprised 32.7% of the total whale catch. During the hundred years of the contemporary whaling industry there were caught 1148901 sperm whales, and during the last 10 years alone - 243827, or 54.3% of the total catch of sperm whales. During the 1966/67 season there were caught 25 921 sperm whales, 50.2% of the total whale catch in this season. The commercial exploitation of the sperm whales is also being carried out in an irrational manners a considerable number of females are being caught, more than 50% in some regions, and among these are many pregnant aniiiials. In these same herds there are a considerable number of young males. On more than one occasion it has been proposed that characteristics of the biology of these whales be exploited and that only the large males be caught in the cold oceanic zones, into which the females and juveniles do not move. We believe that whaling for these surplus males in the stocks can be continued without harm to the stocks, while the old relatively large females may be removed from the mixed herds from time to time. We will recall that a male of average size gives 7 - 8 tons of oil product alone, while females and young maleseve 3 tons. Unfortunately the extermination of the females and young males in the warm zone is continuing and this will rapidly have an effect on the population numbers of the species. It has already been mentioned on more than one occasion that the present regulations for the conduct of the whaling 37 industry permit the whalers to catch from 30 to 90% immatures of the baleen whales, which will lead to the inevitable extermination of the stocks, but nevertheless today these regulations are still in effect. There was introduced a very belated ban against the catching of blue whales and humpbacks and only until 1970.

However until this ban they were being exterminated as a bonus catch, and this is most terrible for the species. In essence, 26 the commercial exploitation of other species of whales is continuing, but not a single whaler let pass an accidentally noticed, now very rare, blue whale, and so it was up to 1965.

If the ban on the catching of these whales had been introduced immediately after the Second World War or if there had been introduced limitations on the numbers of blue whales caught (and this had been proposed), then the stock would.have gradually reestablished itself. But there were introduced regulations only, according to which the blue whales could be hunted initially from the 20th of January and then from the 1st of February, but these were only for the Antarctic. The blue whale is the most desired catch for the whalers (80 - 100 tons of.unressed weight) and not a single whaler let pass the opportunity to catch it in any region of the oceans.

On more than one occasion it has been pointed out that the characteristic features of the biology of the humpback whales - their trusting nature, the special attachment of the mothers to the calves and their habit of approaching close to shore, - give rise to the necessity for a careful attitude towards these whales. There was some discussion about the 38 possibility of controlling the behaviour of these whales, which, in our opinion (like the Pacific grey whales also), could have been the object of special studies in nature. These characteristic features, however, were exploited by whalers for literally their complete extermination. Already during the last few years there have been exterminated, in all

probability, almost completely, the Australian, New Zealand, African and American stocks of these whales in the Southern

hemisphere, and the Atlantic.and also Pacific (American and

Asiatic) stocks in the Northern hemisphere. The fault for the extermination of the humpback whales lies to an equal deg-

ree on both the shore-based and pelagic flotillas of whalers, but the blue whales, fin whales'.and sei whales have been exterminated and are being exterminated exclusively by-the pela-

gic fleet. It is difficult to say what number of blue and hump-

back whales have still survived-i according to some estimates,

in the Southern hemisphere there still remain 1.5 - 2 thousand

blue whales and about 1 thousand humpback whales, in the Nor-

thern hemisphere,- a few tens of these whales,.and in the North

Atlantic, apparently, - only very few individuals. It is ne-

cessary to secure a complete and-prolonged .(for some tens of

years) ban against whaling for these two species in the first

instance. IMankind should preserve them.

It is necessary to introduce a stringent limitation

of the catch of the three species of whales (the fin whales, sei whales and sperm whales) which are left for commercial exploitation, and moreover there should immediately be introduced • 39

regulations that prohibit the catching of sexually immature • animals. With the situation that has become established in the last few years, We believe that one may speak, with the greatest caution, of a catch in the Southern hemisphere, including the Antarctic, of not more than three thousand fin whales and of not more, if not less, than five thousand soi whales; in the Northern hemisphere in the Pacifie Ocean - no more than 700 fin whales and less than 1500 sei whales. The whaling in the North Atlantic should also be conducted care- fully, without permitting the killing-off of sexually immature whales. There should be prohibited, in the first instance for 27 the pelagic fleet, the commercial exploitation of mixed herds of sperm whales in the warm zone; the minimal length of the sperm whales that may be caught should be 1250 cm. It is necessary to immediately organize an Internatio- nal inspection to supervize the conduct of the whaling industry, and moreover the inspectors should be trained zoologists. In the first instance,this inspection should be organized on the pelagic flotillas. We believe that it is necessary to considerably decrease the whaling fleet and to stipulate this in appropriate international agreements. The equilibrium in nature, in the oceans, has been disturbed and in the near future this will begin to have an effect on other species that are of economic significance to man, on the commercial exploitation of the large crustaceans - crabs, lobsters and shrimps in the first instances the cephalopod mollusks, which comprise the usual food of sperm whales and of ko ii other species of whales also, are increasing their numbers h'ey are the worst enemies of the crustaceans. Therefore for a long period of time we have been striving to organize a complex interdisciplinary scientific expedition for the study of the biological resources of the oceans of the World, to obtain a more complete familiarity with the life of the remaining populations of whales, including studies in the warm zone of the oceans.

BIBI4IOGRAPHY

j1HTEPATYPA

3engomm. B. A. Xiintitimeme ncrpe6nennc buiponoro c -razta HHTOB. cflpnpo- D,H». N2 4, 1935. - 23emioowc B. A. Kline, itx npombicen n noaax An-ram-mat H cenepnoii tfCTlP Titx.oro omealia H coo6paaceinia 0 COCTORHUH sanacon. C6. ‹Mopcnie maeKoruira- loutlie». M. «Hopi», 1969. 33enh:oeutt L. A. KIITlit H naaincron B Awrapternoe. C6. aMopcime 111:101COMITB10-• itpie». M., el layica», 1969. KAymo3 C. K. Ytiac.rb larron..«Hplipoito», N: 3, 1958. 5 Cmpune II. A. YtiacTb Enron. «Hplipoo,a», .1\111 11, 1928. b Chittleborough R. Dynamics of two population of the Humpback Whale, Me- . gaptera novacangliae (Borowski). Australian Journal of Marine and Freshwater f*search, vol. 16, no I, April, 1965. Datebin W. H. Movements of Humpback Whales marked in the South West ' Psicific Ocean 1952-1962. Norsk—Hvalfangst—Tidende, no 3, 1964. b lia qasi Kyo and Montle Katsuji. A Call for the Protection of the Whale. To-- Flom.' Imperial University, .1926. 9 Interitalional 'Whaling Statistics. NN 1—LXII, Oslo. 1930-1969. 10 Mackintosh N. A. The Southern Stocks of Whalebone \Phales. Disc. Rep.,. 4YI, v19.14%lf angs tens His tore. Oslo, 1922. 12 Slijper E. J. Whales. London, 1962.

1. Zenkovich B. A. The rapacious extermination of the world stocks of whales. "Priroda" ("Nature"), No. 4, 1935.* 2. Zenkovich B. A. Whales, their commercial exploitation in the waters of the Antarctic and of the northern part of the Pacific Ocean and considerations on the state of the stocks. Sb. "Morskie mlekopitayushchie" (Symp. "Marine mammals"), Moscow, Publ. "Nauka", 1969.

* Translator's note. Sic. but probably 1965. kl

3. Zenkovich B. A. Whales and plankton in the Antarctic. • Sb. "Morskie mlekopitayushchie" (Symp. "Marine .plammale"), Moscow, Publ. "Nauka", 1969. 4. Klumov S. K. The fate of whales. "Priroda" (Nature), No. 3, 1958. 5. Smirnov N. A. The fate of whales. "Priroda" ("Nature"), No. 11, 1928.

11. Risting S. The history of whaling. Oslo, 1922. UDC 599.5+599.711.5 V. I. Krylov and L. P. Medvedev

OBSERVATIONS ON CETACEANS AND PINNIPEDS 28 DURING THE 13th SOVIET ANTARCTIC EXPEDITION (SAE)

CETACEANS

Regular observations were carried out along the course traced by the expedition vessels in the Atlantic and Southern oceans, from the 21st of November 1967 until the 4th of May 1968. During the course of the 155 days of observation there were traversed, in the light period of the day, 10,726 miles. Out of this total period, 73 days or 47% of the time had conditions of impeded visibility (storm, fog, rain, snow); there were traversed 11.369 miles, or 41% of the voyage, of observations. Our studies were in practice reduced to visual observations, since the carrying out of investigations from the ship, which was servicing the Antarctic stations, was made difficult by the lack of time. During the entire period of the observations there were noted, in addition to a few unidentified specimens, about 1010 head of cetaceans; blue whales (Balaenoptera musculus), fin whales (Balaenoptera physalus), sel whales (Balaenoptera borealis), humpbacks (Megaptera nodosa), lesser rorquals or minke whales (Balaenoptera acutorostrata), sperm whales (Physeter catodon), beaked whales (Ziphidae), killer whales (Orcinus orca), pilot whales (Globicephala melas) and also small dolphins (mainly of the genus pAlphinus), which were combined into one group and are subsequently simply termed "dolphins".

Table 1. The numbers of cetaceans encountered during the 13th SAE

Ta6aulta 1 Ko.nunecTno miT0o6pa3kMix, ncTpenemmx n 13-ri CAD

A . . Baleen . ,:carkeeN Toothed3y5. K0/111MCCTDO . Pantmu nemam MItAb 1.1(.•yrimee S m emote 11+pyllil. S • NIC.1101C ItellOACMIn Gem- rpm- cel- • K:nouo- RocaT- rpim- Regions Periods' WMICC Renbckunu -l:1E1.1Ma I naabt nung roP69 `in nor pmam Ë h 1 1 CenepHoe mope — 22-30 692 1 1 4 78

3amfflan Acppl= Hon6pn . 1-25 2726 4 1 5 73 2 . 40 127 2 ganap — ntbm - Olummierp* aseKa6pn (Anrapima,a) 3 Mammil — 26 neKa6pn 1473 • 3 125 3 29 20 BUIJIIIIIrT011 — 9 nunapn 4, flonan 3e.lan,anst -- 10 mmnn— UM 3 P 4 12 M 3 4 7 1 24 °moo BaTepaoo* 22 cpegpaan (10wimm IlleTamu- . cHne ocTpona) • Lualmc- 23 (1)eapa.rm 1 163 1 M 5 eranniin • rayaen—cTannun — 19 mapTa . . Monuenula51 . 6 Cramlun 1V1o.rma,m.. 20----:30 435 12 5 . 96 20 Han — par10II CTilli- mapTa , 1.1,1111 F1Q130J123apell - • ' enan . rl AtiTapICT11,11,Z1 — 31 hiapra — 1045 . - M 4 43 2 . 8 ' 'Oxman A(1)pm(a W mmenn . . .8 Mble l'irOJiblIbln — 11-28 1270 2 1 182 KaHapcHne oeTpona anpean 311 17 351 12 5 114 5 431 , Beer° Total 1 a6.1oRe11ufl HO Dpcmyt CTOHH101 y nmegHoro nrucra aepcxo,na (y mbtca 4.11:1bmiep 22-25 1V111, y °man BaTep.lim t.D. un—nan.' BK:trovettbt peay.Ttbrant I e Included are the results of observations during the stop at the last point of the voyage (at Cape Filchner, 22-25 August, and at Waterloo Island, 27 January - 22 February).

A. - Number of miles of observation 1. - large; s. - small a - blue whales f - sperm whales

b - fin whales g - beaked whales o - sei whales h - killer whales d - humpbacks - pilot whales e minke whales j - dolphins 1 - North Sea - West Africa 22-30 November 2 - Dakar - Cape Filchner* (Antarctic) 1-25 December 3 — Mirnyy - Wellington 26 December - 9 January 4 — New Zealand - Waterloo Island*(South Shetland Islands) 10 January - 22 February 5 — Bellingshausen Station - Molodezhnaya Station 23 February - 19 March 6 — Molodezhnaya Station - region of Novolazarevskaya Station 20-30 March 7 — Antarctic - South Africa 31 March - 10 April 8 - Cape Agulhas - Canary Islands 11-28 April. 144

The distribution of the encountered cetaceans according to the sections of the course of the voyage of the NIS*"Profes- sor Bize" and the d/e*"Ob'" is shown in Table 1. During the passage from Leningrad to Dakar a few cetaceans were encountered on rare occasions. Most widely distributed from the North Atlantic to the warm waters are the dolphins, while the large whales were encountered only to the south of 40° lat. S. All of the animals were observed close to coasts. Further, during the passage from West Africa to the Antarctic continent, the dolphins were encountered only in the tropical zone, in the very northern part of this section. The humpback and sperm whale were noted in the Atlantic; the fin whale and sel whale were noted in the Antarctic, i.e. to the south of 500 lat. S., in the Indian sector of the Southern Ocean. The sel whale, which is generally a relatively warm- loving species, was encountered even right beside the edge of the landfast ice at Cape Filcher. On the whole, as we moved southward, there was an increase in the numbers of small whales: minke whales and killer whales - amidst the floating ice The main accumulation of whales: 3 finwhales, 40 minke whales and 17 killer whales, was encountered on the 18th of December at 600 10' lat. S. (70° 08' long. E.) (the coordinates 30 here and subsequently are given for 1200 hours ship's time on the day of the encounters). This section was on the border of whaling sectors 3 and 4. In other regions: in the Indian sector of the Southern Ocean, during the passage from Mirnyy to Wellington, there were encountered only a few sei whales, though relatively numerous

* Translator's note. NIS - "nauchno-issledovatel'skoe sudno" - research ship; d/e -"dizel'-élektrokhod" - diesel-electric motor shiP. 45 minke whales and killer whales (see Table 1). In the temperate latitudes dolphins were encountered. During the passage from New Zealand to the South Shet- land Islands, in the Pacific sector of the Southern Ocean, the species composition of the cetaceans was the most diverse. There were also encountered relatively more large whales (36% of the total number of cetaceans during the passage), but they were unevenly distributed: almost all were noted close to land, especially such rare species as the blue whale and humpback. As previously, the most numerous species was the minke whale. The main accumulations of whales were encountered on the 27-28th December at 62° 58' lat. S., 94° 04' long. E. - - 62° 19lat. S., 103° 12' long. E. (whaling sector 4): 2 sei whales, 3 sperm whales, 117 minke whales, 25 killer whales, and on the 10-12th of January at 42° 42'lat. S., 178° 05' long. E. - 48° 54'lat. S., 162° 32' long. W. (border of whaling sectors 5 and 6): 5 fin whales, 2 sei whales, 3 sperm whales and 4 beaked whales. There should be separately distinguished the whales which were encountered on the 27-29th of January on the border of whaling sectors 1 and 2 in the coastal waters of some of the South Shetland Islands (Smolensk, Half Moon, Waterloo): 3 blue whales, 12 humpbacks, 2 sei whales and 4 minke whales. During the course of the two-week passage in the Atlantic and Indian sectors of the Southern Ocean (whaling sectors 2 and 3), from Bellingshausen Station on Waterloo Island to Molodezhnaya Station, there were encountered in all 1 minke whale and 10 killer whales, almost all in the inshore zone off the coast of the Antarctic continent. 46

On the other hand, during the relatively short passage lb) from Molodezhnaya Station to Novolazarevskaya Station (whaling sector 3) there were encountered a considerable number of cetaceans. Their numbers increased and the species composition became more diverse as we moved deeper into the zone of floating ice. In comparison with other species, the finwhale and minke whale were numerous, the former on account of the size of the accumulation, the latter on account of the frequency of encounters of small groups. The minke whale was also observed in openings in the landfast ice. The main accumulation of whales was encountered on the 21st-22nd March at 66 ° 42 lat. S., 300 42 long. E. - 67° 42' lat. S., 17° 30' long. E. (whaling sector 3): 12 finwhales, 5 sei whales, 11 minke whales and 8 killer whales. Close to this place, when the diesel-electric motor ship "Ob'" was proceeding from the Antarctic on the return course to the north, there was also encountered an accumulation of whales: 11 fin whales, 3 sei whales, 2•sperm whales, 45 minke whales and 5 killer whales. This encounter occurred on March 31st at 69 ° 00' lat. S., 14° 35' long. E. The abundance of birds and the presence of seals point to a high food content in both regions. Consequently, this part of the Riser- Larsen Sea is biologically productive. Of interest are the facts of the approach of such thermophilic species as the sei whale and sperm whale so far into the ice zone, and also the encounter of 7 dolphins in the waters of the Antarctic on the 6th of April at 51 ° lat. S. 47

Subsequently, during the passage to Cape Agulhas (South Africa) large and small whales (fin whales, sei whales, beaked whales, killer whales) were rarely encountered. However,out of the 10 days of the passage, 9 days had impeded visibility and some animals may not have been noted. During the passage from South Africa to Las Palmas

(Canary Islands) in the temperate and warm waters of the Atlan- tic there were encountered close to land only the sperm whale and beaked whales, and also many dolphins. It should be noted that the majority of the small dolphins (88.4% of their total number) were encountered in the

Atlantic ocean. Almost all of the cetaceans of the other species (91.4J of their total number) were encountered in the Southern Ucean, mostly in the zone of floating ice, to the south of 60° lat. S. As is evident, in most of the regions along the course of the ships there were few whales, they were distributed sparsely and unevenly. Accumulations of commercially exploit- able size were not found, but nevertheless there was observed an affinity of certain groups of animals towards distinct sections, which may apparently be considered as biologically productive.

PINNIPEDS

Observations on the seals were carried out along the path taken by the ships through the ice and also during the period of the work of unloading on the landfast ice and on shore. The ship moved into the ice only during its approach to the Antarctic stations. Therefore the observations on the seals occupied only 38 days, of which 16 days were among the drift ice and landfast ice, and 22 - on the shores of the South Shetland Islands (Waterloo, Smolensk and Shishkova). Five species of Antarctic seals were encountered: Weddell's seal (Leptonychotes weddelli Leec.), the crab-eater seal (Lobodon carcinophagus Hombron et Jaeguim), the sea leo- pard (Hydrurga leptonyx Blaimille), the elephant seal (Mirounga leonina L.) and one representative of the eared seals - the southern fur seal (Arctocephalus Zimneermann, 1787). We encountered solitary specimens of seals during the approach to Mirnyy Station (62° 3)4 ' lat. S., 83° 35' long. E. - 64° 50 lat. S., 89° 32' long. E.). In this region there were noted: 19th December 1967 - 7 crab-eater seals, 1 Weddell's seal; 20th December - 12 crab-eater seals. During the period of observation on the 19th of December the length of the passage through the ice comprised 76 miles in 6 hours, while on December 20th this was 169 miles in 12 hours. Not more than 3 seals per hour were observed. The second, also small accumulation of pinnipeds was observed by us on the landfast ice 17 km from the Mirnyy settlement (66° 22' lat. S., 92° 41' long. E.). In this region there were found only Weddell's seals. Almost all of these were located on the edge of the landfast ice and did not move in further from the edge than 1.5 - 2 km, they generally lay singly or, more rarely, in groups of 2 - 3 individuals. On the day of the arrival of the ship (December 21st) about 25 seals were lying on the ice. After a few hours, however, the animals were frightened away by the ship's company, 119

and towards evening only 3 seals remained on the ice. On the • following days in this region there appeared no more than 2 - 3 seals. We encountered a somewhat greater number of seals during the period of the passage from Mirnyy to New Zealand. These seals, mainly crab-eaters, were observed on 8-degree ice. A fairly large density of these was noted on the 27th of Decem- ber in the second half of the day in the region of 64° 35' lat. S., 91 ° 22 long. E. - 62° 68'* lat. S., 96° 05' long. E. Here there were often 2 - 4 seals lying on one small ice floe. Si- milar cases of basking were recurrent, which depended on the character of the distribution of the ice and, apparently, on the feeding conditions of the region. In all, during 14 hours, of observation (in a 140 mile path) 61 seals were encountered, among which there were 48 crab-eaters, 12 Weddell's seals and one unidentified specimen. We were able to observe a large number of crab-eaters on very light floe ice on the 22nd of January in the Pacific sector of the Southern Ocean, in the Bellingshausen Sea (680 39' lat. S., 83° 35' long. W. - 67° 58' lat. S., 77° 20' long. E.). The main basking grounds (rookeries) of the seals were noted on 5-6-degree ice close to the edge. On 10-degree ice only solitary specimens of seals were encountered. During the course of 5 hours, while the ship travelled a 45 mile path, we counted about 200 seals, of which 170 were crab-eaters and only 27 Weddell's seals. Another large accumulation was noted on the morning of 0 January 23rd in the region of 67° 58'lat. S., 77 20' long. W.,

*Translator's note. Sic. 50 when the ship was emerging from the edge of the drift ice. Literally in a period of 35 minutes in a path section of not more than 4 miles we were able to count up to 115 head. Here 5-6 crab-eaters lay on very small ice floes. Solitary individuals were rarely encountered. It should be noted that during the period of observation there was a dense fog and the visibility was not more than 100 - 200 m. Therefore it must be assumed that there were considerably more seals in this region than we saw. In the Atlantic sector of the Southern Ocean seals were observed in three regions: in the Sea of Lazarev, the Ruser- Larsen Sea and in the sub-Antarctic zone on the South Shetland Islands (Smolensk, Waterloo, Shishkova and their coastal waters). In the Lazarev and Riiser-Larsen Seas in March mainly single seals were encountered. Weddell's seals predominated on the young landfast ice, while on the drift ice the crab-eaters predominated and sea leopards were occasionally encountered. On Smolensk Island on the 27th of January during a par- 33 tial inspection of the shore (over the course of 4 hours) 3 Weddell's seals were noted. Waterloo Island was investigated from January 28th until February 22nd 1968, during the period of unloading of the ship and the construction of Bellingshausen Station. We took part in this work and therefore, because of the small amount of free time, we were able to investigate only a small part of the island (the southern tip). On the north-western shore there were located fairly large rookeries of elephant seals of various sex and age, which 51 comprised 10-20 and, more rarely, 40-50 head. Altogether in 17 rookeries their total number was 830 head. Elephant seals were also encountered singly and in small groups of 5-10 in Collins Harbour bay (on the south-eastern shore of the island). They also appeared occasionally on the shore of Ardley bay. It was noted that distinct groups of moulting animals lay far from the water (up to 500 m) and selected muddy rather than stony sections.

Often on the hauling-out grounds of the elephant seals

there were also found Weddell's seals, crab-eaters, sea leopards and =2- fur seals. These species of seals lay not far from the sea elephants, singly or 2-3 together. During the entire period of our stay on the island we were able to count on the shore rookeries 59 Weddell's seals, though only 3 sea leopards were encountered and 2 crab-eaters (on the most south- eoLsterly part of the island). On the south shore (in Failds straight) the Weddell's seals and crab-eaters form independent rookeries of 2 - 5 head. Along the whole extent of the shore on February 14-th we counted 20 head with a predominance of Weddell's seals. Elephant seals were never noted along this section.

In Ardley Bay we observed crab-eaters afloat on more than one occasion. During the period of our observation only

9 out of 77 crab-eaters were on the shore. The southern fur seals were encountered considerably more rarely on the island. We found these animals only on the north western shore of the southern part of the island. During the entire period on the Island we noted 9 fur seals, of these 3 were females, 4 bachelor males and 2 yearlings. 52

On Shishkova Island (at Cape Sukarlov). there were found 15 fur seals, beside these were lying 2 elephant seals and one

Weddell's seal. With the re-establishment of the population there is apparently occurring a spread of the southern fur seals,, which have again appeared on the South Shetland Islands. Consequent- ly, while ten years ago the southern limit of the range of this species was the island of South Georgia (Zemskii, 1960), at the present time the South Shetland Islands should be considered as the southernmost point of the range. The diversity of the species of seals in the region of

Waterloo Island As apparently conditioned by the rich food base. In the plankton samples, which were taken by us at the 34• hydrobiological stations close to the South Shetland Islands, there was noted small krill. This is often thrown up also by storm waves onto the shore of Waterloo Island, which was also observed by us on several occasions. In the plankton samples, which were taken on sections of the passage from the South

Shetland to the South Orkney Islands, in addition to krill there were found squid larvae. The aqualung-hydrobiologists

of the Zoological Institute of the USSR Academy of Sciences, who were working on the shelf of Waterloo Island during the 13th Soviet Antarctic Expedition, found a rich benthofauna.

During the 13th Soviet Antarctic expedition investiga-

tions were conducted over an extended period of time over con-

siderable regions of the Southern Ocean and also the East Atlan-

tic. However, for the exhaustive gathering of data, especially on the distribution of the populations and also on the biology 53 of the marine mammals in the ice zone, it would be necessary to have a complex high-latitude expedition, with the participation of a ship of the ice-breaker type and aviation for scouting and observation. 54

UDC 599.532 G. A. Klevezal' and D. D. Tormosov

THE SEPARATION OF LOCAL GROUPINGS OF SPERM WHALES 35 BY THE CHARACTER OF THE DENTINE LAYERS OF THE TEETH

The separation of local groupings of commercially exploited animals is of considerable interest from the theoretical point of view and is extremely important for the proper organization of the commercial exploitation. The dissociation of groupings of mammals may be established by differences in the value of the coefficient of variation of morphological features, for example, parts of the skull (Yablokov, 1966), on the basis that in freely mixing populations the variability is uniform. In the case of the large whales t however, it is technically difficult to collect material for this type of analysis. In recent years the local groupings of large cetaceans have been distinguished by the biochemical characteristics of the blood (FUjino, 1965, and others), but this type of work is complex from the methodological aspect. At the present time the age of sperm whales is determined from the number of layers in the dentine of the tooth and for this purpose teeth are taken from practically all whales killed. This suggested to us the idea of attempting to make use of the character of the layers in the dentine of the teeth for distinguishing local groupings of sperm whales, taking into consideration the available experience on distinguishing groupings of fishes by the character of the annual layers in the otoliths (Mina and Tokareva, 1967). 7-

The material studied included: 100 females, caught from 1961 to 1968 in various regions of the Indian and Atlan- tic Oceans: 97 males from the South Atlantic region (40-47° lat. S., 30-600 long. W.), caught in March-April 1962; 100 males from a region in the south-eastern part of the Indian Ocean (40-5 0° lat. S., 100-1300 long. E.), caught in March- April 1965, and 47 males from a region in the south-western part of the Indian Ocean (40-60° lat. S., 30-60° long. E.), caught in March-April of 1962 and 1965. Longitudinal sections of all of the teeth, about 0.3 cm in thickness, Ng= obtained on a special machine tool, were polished on one side and examined in transmitted and reflected light (Tormosov, 1969). 10) Even on first inspection it could be noted that the structure of the layers was not uniform in the dentine of the teeth of different individuals: the layers differed in sharp- ness, in the degree of contrast of the individual bands, in the internal structure etc. At the same time the character of the dentine layers in two neighbouring teeth of one individual was uniform. Very striking were the differences in the structure of the dentine layers of the teeth in individuals of different sex: in the teeth of the females there could generally be seen the distinct more striking layers, set apart from one another and subdividing the tooth into sections (Fi- gure 1). We have conditionally termed these striking layers "otmetkint The "otmetki" have been detected in the teeth of

* Translator's note. "otmetka" may be translated by "note, mark, blip, level, datum". Possibly correlated with "otmetit' ptichkoi" - "to mark with a tick", i.e. 1,0/. 56

a 6 Puc. ' rIpw,o.nhabic akio(l)ht 3y6oa 133p0CSIbIX camoK Kaula.noToo. Orpmeaabol CBCT, B11,7.111,1 60J1Ce stpKoe > paa- 'tor° xapaKTepa (cpaoloarb I-a II 1-6). «OTNICTIiIi>> :.yKa3anbt crpénimmil.

Figure 1. Longitudinal sections of the teeth of adult sperm whale females. Reflected light. The more striking layers, the "otmetki", of various character (compare la and lb) are evident. The "otmetki" are indicated by arrows.

63% of all of the examined females. In 10% of all of the males there could be seen in the dentine distinct more striking streaks, but these are not repeated in so regular a fashion along the length of the tooth as are the "otmetki" in the dentine of the teeth of the females. In 80% of the cases an "otmetka" is composed of one striking, clearly distinguishable layer of dentine, in the remaining cases - of 2 - 6 similar layers, adjoining one another. In 90% of the cases between the "otmetki" there can be seen 2, 3 or M. normal layers of dentine, while in the remaining cases there are 1 or 5-8 layers. In one and the same tooth the number of layers between the "otmetki" may be dissimilar, but at the same time there were not revealed any regularities in the 57 pattern of change of this number in step with the growth of the tooth: out of 24 females which had more than three "otmetki" per tooth, in 9 these were situated at an even distance from one another, in 4 the distance between the "otmetki" diminished from the apex towards the root of the tooth, in 4 this distance increased, while in 7 it changed at random. As was shown by the comparison of the number of "otmetki" in a tooth with the number of layers of dentine, in 60 females, the teeth of which were not ground down, there was no regular pattern of increase in the number of "otmetki" in a tooth in step with the increase in age of the female (Figure 2). In order to reveal any connection between the formation of the "otmetki" and the pregnacies and parturitions of the female, we compared the number of "otmetki" in the tooth with the number of traces of corpora lutea in the ovaries, and also studied the character of the last layers (according to the time of their formation) in the tooth in pregnant females. The number of "otmetki" was not correlated with the number of traces of corpora lutea in the ovaries (Figure 3). Out of 29 pregnant females, in 9 there were no "otmetki" in the teeth at all, in 10 the last "otmetka" was located at a distance of 1-2 layers from the edge of the pulp cavity of the tooth, in 5 in the lower part of the tooth to the pulp cavity there were evident from 6 to 20 uniform layers, wUle in the remaining females the pulp cavity was closed. All of this does not permit one to relate the formation of the marking in the tooth with the pregnancies or parturitions of the female. It seems probable that the differences in the character of the annual layers of dentine 58

I0 LJ 9 •11 % ' o Zi 7 E .p ct, 6 0 • •

CH 0 4 • • e • • • • t. O +,,-,;■ • e 3 • • • • .rt 2 •••• J 10•• 1* •

› : c 5 /0 /5 20 • 25 so 35 Koncivec/7780. c..720e:7 e.,:zi/A7 Number of layers of dentine Pile. 2. CpaBlICIIIIC KO:IWIECTBa «OnleTOK» B ay6e C KOMPICCTEOM CJIOCB B RCIITIIIIC y camoi: KaulaooTois Figure 2. Comparison of the number of notmetkin in the tooth,witWthe number of layers of dentine in sperm whale females.

`') 8 O 1%7 •P. 6 O 4 `1.q s 0 ts 5 • .ce .0 . • • O? 4 • • • • • Q. e e • ■9 • eri 0 q12 :• • • • e. o • ka let ° • e • q • •. • 2 , 4 ,6 a 10 • Al5tnegeemeo C./iedod .2,«.../7/77,51X /77e./7 NumberCieeeMe.iiiiDC.Wa./ or Traces g ,91./1/U.KCI.2:of corpora lutea of pregnancy in ovaries Pile. 3. Cparnientle KO.,littleenta «OTIUCTOK» B syÔe C KOZIMECTISOM cae.aou x:elnux Tea B smtuntEax y CaMOK Kat13.lo-rol3

Figure 3. Comparison of the number of wotmetki" in the tooth with the number of traces of corpora lutea in the ovaries of sperm whale females. 59

• ' • • • Pic. 4. lipononbitliiii mud) .3y6n inpocnoro camna KauranoTa. Orpanzennbiii cner. C.ioii e,cirrnna — «xopowire», epannomepnble»

Figure 4. Longitudinal section of a tooth of an adult male sperm whale. Reflected light. The layers of dentine are °good" and "even°.

••01.0....•••••••• ■•1 in the teeth of male and female sperm whales are related not to the sexual affinity of the individuals but to the differences in the character of the migrations of the males and females. It is noteworthy that the ratio of the numbers of females with and without uotmetki" in the dentine of the teeth, judging by our data, is about the sanie in the Atlantic and Indian Oceans. In examining the dentine of the teeth of males there are no striking peculiarities that stand out so clearly, but it is immediately evident that in some cases the layers are 60

a 6

" Pue. 5. Ilpuoabuble MAI! (1)111 133pOCJILIX camicols a-ama.norou. CBCT. Caou Real-iota — «y.lon.neTeopirre.nbabte», «par, Homepuble» (a) ni (eyoit.nentopinenbilhie», eaepaBoomepiime» (6). _ OrpeoKamit yi(a3aub1 6o.nee nrnme nonocioi

Figure 5. Longitudinal sections of adult male sperm whales. Reflected light. The layers of dentine - "satisfactory","even" (a) and - "satisfactory", "uneven" (b). The more striking streaks are in, dicated by arrows.

easy to read, while in others they are difficult to make out. In order to judge the similarity or difference in the character of the layers of dentine in the males, which were caught in different regions, we made use of the following appraisals 39 of the structure of the layers: "good" - layers easy to read, either no supplementary streaks in-between or these do not interfere in distinguishing the basic layers (Figure 4); "satisfactory" - difficulties arise in counting the layers, since the layers have insufficient contrast or there are present many internal streaks which interfere with the demarcation of the layers (Figure 5); "poor" - the layers are practically impossible to count. "even" - all of the layers on the section 61 are uniformly good, satisfactory or poor; "uneven" - individual layers or groups of layers are better or worse than the rest. Each tooth received two appraisals; one - characteri- sing the definition of the layers, the second - their evenness; for example, good-even, satisfactory-uneven etc. We calculated the ratios of the teeth of each category in sample I - teeth of sperm whales from a region in the South Atlantic, and in sample II - from a region in the south-eastern part of the Indian Ocean, and determined the significance of the differencec of these samples from the ratio of each category, utilizing the criterion of significance of differences of sample ratios (Plokhinskii, 1961>. The samples differed significantly on the basis of the ratios of the teeth of all categories (Table 1). Having calculated the possible values of the ratios of each category for both samples, we found that the samples over- lapped insignificantly, at the first level of significance, only in the case of the possible ratios of the "satisfactory" category, while for the possible ratios of the remaining cate- 40 gories the samples did not overlap at all, at significant levels of 99 and 99.9% (Table 2). To check the objectivity of the distinguished catego- examinations ries, three independent stmling of each sample were carried outs two - by one of the authors, with an intervening half- year interval; one - by the second author. The differences 41 in the values of some of the categories in the different examinations were fairly considerable, but in all of the independent examinations the samples from the region in the South Atlantic 62

Table 1. Significance of differences of two samples of sperm whales according to the ratios of teeth of different categories. - -

TaGnHUa I

AOCT06CPHOCT6 pa3TlHlIHSl Jj13jrX BI-A60pOli kaWdJIOTOB f10 FiOJIC 3yÛ0R pa3Hb1Y K£1T2r0p1lFt Basic ratioS,OcnoHHme Ao.111, %

,b'AOUncrno- ,PanuO;aep- Pa11ou I a X0110 el I7noxue• Region a ^NTIVIWC` c It1d•

1 L3bt6opl:a I, IOxcllasl AT- natrrm;a 97 40 58 5 74 2 Bl,tdopsa II, Ioro-uocTOl; I'It11[Hilcxoro oxeaHa 100 7 76 22 30 3 BenH4HUa xpHTCp1;sI Zoc- TOBCpHOCTH B6IÜOp09110N t=6,6> t=2,5>to3 t=3,7> t=6,0> pa3HOCTU, t t001

a - "Good" b - "Satisfactory" c - "Poor" d - "Even" 1 - Sarple I, South Atlantic 2 - Sample II, south-éast Indian Ocean 3 - Value of criterion of significance of sample differences, t.

and from the region in the south-eastern part of the Indian

Ocean differed significantly according to all of the indices.

With such relatively unobjective categories as "good" or "satzs- factory ; one of the investigators may overstate or understate the appraisal, in comparison with another investigator, but,- since he overstates theappraisal equally in both cases, the value of the differences between the samples is retained. In a similar manner were examined the teeth of the whales caught in the south-western part of the Indian Ocean. The ratio of the teeth of each category in this sample was 63

Ta6uiia 2 RoacpaTeammte itarepaaab, BCJIIPHIHE4 reaepa.nbtion Rona aaacp,oil aareropna 3y60e aawaaoToa H3 pa3t1b1X paiionoa

A OCHOUllbl j1.0,111, ompa-ame* „mime-mop.« „n.rinue' eanHogrpti 6 . 6. e`16. Paon O - .0

Region 110.1a o 110210 110/10 110110 a .0 ag rI O un . .1 P.C.) U tt o. 0 u oo=o g 2 X

1 Cpynna 1, 97 40 26-54 58 46-70 5 0-10 74 56-92 'Oman AT11311- THKa 2 1-pynna 100 7 0-15 76 68-84 22 121-32 30 15-15 WID-BUTOK Hap,aficKoro oxcana 3 Cpynna III, 47 8 68 28 31 toro-aanaa, Alliicaoro oue- ana

A - Basic ratios, % a - "good" b - "satisfactory" c - "poor" d - "even" X - ratio y - confidence interval at the level of significance. 1 - Group I, South Atlantic 2 - Group II, south-east Indian Ocean 3 - Group III, south-west Indian Ocean.

very close to the value of the ratio of the corresponding category in the sample from the region in the south-eastern part of the Indian Ocean (Table 2). . In the case of the sample from the region in the south- western part of the Indian Ocean, some of the whales were caught in 1962, some in 1965. We compared the ratios of the teeth of each category in the group caught in 1962 and the group caught in 1965, and found that the groups did not differ 64• significantly. From this it may be conjectured that the finding

of the differences between the samples of the population of sperm whales in the South Atlantic and the population from the region

in the south-eastern part of the Indian Ocean is connected with the localization of these populations. Thus, judging by our data, the sperm whales caught in the region of the South Atlantic represesent a distinct grouping which does not mix with the sperm whales from the southern part

of the Indian Ocean, while the sperm whales from the south-

eastern and south-western parts of the Indian Ocean cannot be

considered as representatives of different local groupings.

IInfortunately, we have no information on the localization of

groupings of sperm whales in the. Southern hemisphere, obtained

by other methods. it is true that, according to the preliminary

data of D. D. Tormosbv, differences were noted in the age struc-

ture of groupings of male sperm whales, taken over several years

in the Atlantic and Indian Oceans, which is indicative of a

locali.zation of these groupings.

As to the causes of the differences in the structure of

the layers of dentine, the contemporary knowledge of both the

biology of sperm whales and of the mechanism of the formation

of the annual layers does not give the possibility of formula-

ting a definitive opinion, but it may be conjectured that these

differences are related to the temperature characteristics of

the water in the Atlantic and in the Indian Oceans. This, in

particular, may explain the predominance in the Atlantic of

sperm whales with even layers of dentine. The changes in the

thermal conditions of the water medium in the South Atlantic are

more intensive than in the Indian Ocean in one and the same 65

latitudinal zones. In the Atlantic the temperature of the water changes fairly sharply from the equator towards the south, espe-

cially in the regions of the permanent cold currents, the Ben-

guela and Falkland currents. In the Indian Ocean there are no

permanent cold currents along the coasts of Africa and Austalia,

and the overa7.7-change in temperature here from the equator to-

wards the south is smoother. Changes in the thermal conditions

of the water masses in the Indian Ocean depend on the monsoon

circulation, and therefore they are not so clearly expressed.

Besides this, the thermal potential of the water masses in the

.Atlantic and in the Indian Oceans is different: for example,

the mean annual temperature between the tropic of capricorn and

the equator at a depth of 200 m in the Indian Ocean is 15 -.20°C, W, while in the Atlantic this is 10 - 15°Ct at a depth of 4.00 m the main area of the Indian Ocean is occupied by waters with a tem-

perature of more than 10°C, while in the South Atlantic these

waters are at less than 10°C (Marine Atlas, vol. II, maps 16,

17. pubi. Naval Forces Staff, 1953)• It is possible that during the migrations of the male

sperm whales in the Atlantic the sharp drops in the water tem-

perature serve as the "organizing factor" (Mina and Tokareva,

1967) which unifies and brings to a common scheme the periodic changes in the rate of growth and, consequently, in the charac-

ter of the layers of dentine. Therefore a large part of the

sperm whales that were caught in the South Atlantic had even

layers of dentine. In the Indian Ocean, where there are no

sharp drops in the water temperature, there is no "organizing

factor" which decreases the variability of the periodic changes 66 in the rate of growth and in this manner unifies the structure of the annual layers. This probably explains the predominance among the male sperm whales in the Indian Ocean of individuals with uneven layers. It is possible that the greater drops in temperature in the Atlantic ensure not only the evenness but also the greater contrast of the layers of dentine in the male sperm whales of the Atlantic, since they increase the extent of the periodic changes in the rate of growth, which determines the degree of contrast of the bands of dentine (Klevezal' and Kleinenberg, 1967). Thus, our investigations indicate that it is apparently possible to determine the localization of groupings of sperm whales according to the character of the annual layers of dentine. This method, of course, requires further elaboration. It is necessary, in particular, to reduce to a minimum the di- vergences in the evaluations of different investigators. How- ever, even in this form distinct results may be obtained without the application of complex apparatus and laborious analysis. Probably in a similar manner, based.on the character of the layers of dentine in the teeth, there can be determined the localization of groupings of other toothed whales and other mammals, while the localization of the groupings of the baleen whales may be determined on the basis of the character of the layers in the ear plugs. 6?

REFERENCES

.1114TE') ATYP A C.K.neee3aitb r. A., Kizefiticii6epe C. E. Oupe,],eaeuite uoapacra mneKonitTaiow,ux. no CAOHCTIMI mytiTypam 3y600 H iocru. M., «HavKa», 1967. .I.,Muna M. B., ToKapeca T. H. 0 crpywrype oi-oairro8 Gadus morhua callarias toro-nocToquoil guilt ria.nTui1moro mopsf. ,e13onpochi iix-ruo.normu>, T. 7, mm. 2, 1967. Top.irocoa MaroTouneuite urnubou sy6ou. KaIHNIOTOB. «Pb16110C X0351r1- CT130», IN12 7, 1969. 4. HiroxtuicKuil H. A. 1.3tio1Ienitst. HonocetipcK. 1961. e 576nonoa A. 13. 1,13meimmocTb wiexonirraionuix. M., diayKa», 1966. 6, K. Tudjina. On the serological constitution of the Fin whales II. Further studies an blood groups. Sel. Rep. whale Res. Institute, No 11, p.p. 85-98. 1956.

1. Klevezal G. A. and Kleinenberg S. E. Determining the age of mammals by the layered structures of the teeth and bones. Moscow, "Nauka", 1967. 2. Mina M. V. and Tokareva G. I. The structure of the otoliths of the cod Gadus morhua callarias in the south-eastern

part of the Baltic Sea. "Voprosy ikhtiologii" ("Questions of Ichthyology"), vol. 7, No. 2, 1967. 3. Tormosov D. D. The preparations of sections of the teeth of sperm whales. "Rybnoe khozyaistvo" ("The Fishing Industry"), No. 7, 1969. 4. Plokhinskii N. A. Biometrics. Novosibirsk. 1961. Yablokov A. V. Variability of mammals. Moscow, "Nauka", 1966. 68

UDC 599.51 V. V. Zimushko

INFORMATION ON THE REPRODUCTION OF GREY WHALES 44

The study of questions concerning the breeding of whales is of considerable significance in connection with the problem of the conservation of whale stocks. With regards to the grey whale, at the present time there is little information on the biology of reproduction of this species in both the Russian as well as the foreign literature. Fragmentary data are given in the studies by Ch. Scammon (1874), B. A. Zenkovich (1937), A. G. Tomilin (1937, 1957), M. P. Vinogradov (1949) and D. Rice (1963). In particular, even such important questions as the period of commencement of sexual maturity and the cyclic nature of the reproduction have been inadequately studied up to the present time. From analogy with other baleen whales it was accepted that the grey whales become sexually mature in two years or even earlier. However there was no factual information on this subject, obtained from the application of a sufficiently precise procedure for determining the age, and it is not surprising that certain investigators cast doubt on this assumption (Chapskii, 1963). Recently it was established that in some species of baleen whales the reproductive cycle is not biennial but shorter (Kulikov and Ivashin, 1959; Zemskii, 1961). In this connection there is evidently no reason to doubt the need for a more detailed study of the biology of reproduction of the grey whales. We have at our disposal information which permits us to obtain some idea about the rate of reproduction of the grey whales. This information is presented in the present paper. 69

THE PERIOD OF ONSET OF SEXUAL MATURITY 41 The question of the size at which grey whales become

sexually mature was considered by us previously (Zimushko, 1969). We arrived at the conclusion that males become sexually mature on attaining a length of about 11.5 m, while females mature and-_: commence participating in reproduction after attaining a length

of about 12 in. The information on the determination of the

period of the onset of sexual maturity is presented below. At the present time the ear plugs are most frequently

utilized for determining the age of the baleen whales. Until

now this method has been accepted as the most precise. We utilized this for determining the age of grey whales, at the same 4-5

time considering that two layers are formed in the plugs each

year (2imushko, in litt.). The ons^t of.sexual.anatur.ity was

determined by means of an analysis of the reproductive organs.

Examinations were carried out of the ovaries of the females, the

uterus and the milk glands. In the males there were taken into

consideration the size and weight of the testes, the number of'

open sperm ductules and the presence of spermatozoa in the epi-

didymides. Having determined the physiological state and age of 66

individuals, we selected a sample of those animals in which

there were 12 layers in the ear plugs (Table 1). The whales which had more than 12 layers in the plugs were sexually mature.

8 layers was the mznimal.number in females ovulating for the

first time. Primigravid females, 12.3 and 12.5 m in length, had 1i 11 and 12 layers, respectively, in their ear plugs. In a primi- parous female, 12.8 m in length, there were counted 12 layers. Table 1. Data on the onset of sexual maturity of grey whales

Ta6an it a 1

fl,aintr-Àe no aacTynaeaato no.noaoii apeaocTa cepbix KtiTOB B. KO.11-1.1eCISO Cnocti n rime relia, clnI3110/10rirteCROC cocrosutste 111)061(C .1Inuica

Females CamKu 5 . 9,8 Henonono3peaa1 a 5 9,8 1Ienomono3peoan a 5 10,3 HC110.10B03pCJI351 a 6 9,7 iienanotimpeJaR a 7 - 11,8 iien000noapenan a 8 11,5 ancpable 6epemeanan b 8 UM ifeno.qoao3peaa11 a 9 UM noà0i3o3peaa5I (.!Lma cae- aa mamma) C 11 11,8 ne00noBo3pe.lasi a 11 ' 12,3 anepabie 6epemeiman b 12 12,5 anepable 6epeme1luan b 12 12,8 anepautc pom:amuan d • Males Ca bl 4 9,1 fienonono3penbet a 4 10,6' fien000ao3paaa a 6 10,7 1ic.noaoBo3peaa)-1 a 6. 11,5 nenanoso3pe:ml1 a 7 11,2 co3peaanutaii 8 11,6 co3peualownii •e 8 • 11,5 no.1on03pe.lbdt f

A. - Number of layers in ear plug B. - Length of body, m C. - Physiological state

a - sexually immature b primigravida c - sexually mature (traces of two ovulations) d - primipara e - maturing f - sexually mature.

The males which had up to 6 layers in the plugs were sexually immature. The males, 11.2 and 11.6 m in length, which had 7 and 8 layers in their ear plugs and not completely developed testes were referred to as maturing. 71

14,0 o

E mo

o 0 • - /20 0 .0 % *9C.I7O8eble ocroamovesain : 4-1 110 0 /7 .50 0 - cpeartue 3/r1Jveace7 .e; icpu8a77 no cpedeum 3//o4eianie +, t:; - mamemcimuirecA17;$7 xpe.18czer

00 4 à :7 d e ')/ à Th 25 /6' /7 15 19 20 2/ 222324252C. qucno cnone 8 6tareb/..z.- apotikax Number of layers in ear plugs

PIK:. 1. Tmn poc-fa camoN cupbix KIITOB

Figure 1. Rate of growth of grey whale females. . * Legends n = 50 o - average values - curve according to average values - mathematical curve

On correlating the number of layers in the plugs with the length of the body it was established that after 8-10 layers had been accumulated in the plugs the rate of growth decreased in the grey whales (Figures 1 and 2). This drop in rate evidently occurs at the time of sexual maturation and may serve as one of the indices of the period of onset of sexual maturity. In Figure 1 is shown the relationship of the body length of the females to their age. One curve was constructed according to the average values, the second was calculated. The latter was obtained by applying the method proposed by N. A. Plokhinskii (1961). The curve of the rate of growth of the males (Figure 2), in view of the small'numbers of data, was constructed on the basis of the absolute values of the body length. ▪

14,0 * Ucnoefletile odes/eager/zee: n = 2/ -Oeconfoinebte3eaveHus 1 /..?0

O ;3' /2.0

O «0 .e tlez/0.0

• 4 25 26 27 20 29 303/ 0/011121314/5 /7 (8/ 9 202/ 22 232 ,. .5- 6 7 8 1 t/c/c.uo c.n0e6 6 ycz//ft.t.x npoekax Number of layers in ear plugs *Legends n = 21 . x absolute values

Pi4e. 2. Temn pocra camnon cepbut 1{11T0I1

Figure 2. Rate of growth of grey whale males.

It was mentioned above that some information,concerning the period of the onset of sexual maturity of grey whales, is present in the study by Rice (1963). Ricobtained the following results from an examination of 6 grey whales. The males which had attained sexual maturity and had an average length of about 11.9 m, had accumulated 10 layers in their ear plugs up to this time. One female, 12.7 m in length, had about 11 layers in the plug and was a primigravida. From what has been Said it 18 evident that our information and the data of Rice are basically in agreement. Thus, the grey whales begin to participate in reproduction when they have 8-11 layers in their ear plugs. Each year there are formed two layers in the plugs, which means that they mature in the 5-6th year of life, the males, apparently, mainly in the fifth year. 73

SOME DATA ON THE REPRODUCTION

In characterizing the periodicity of reproduction it should be indicated in the first place that by reproductive cycle we have in mind mating, pregnancy, lactation and the following recovery period. As has already been mentioned above, at the present time it is considered that the sexual cycle in the female whales is biennial. The duration of gestation is about one year or a little less, the lactation period lasts for about six months (Scammon, 1874; Tomilin, 1957; Chapskii, 1963). The attitude exists that, if females give birth once every two years, then half of those, or even more, that are capable of reproducing remain barren each year (Severtsov, 1941). According to our information, in 1965 and 1967 fewer than half of the females were gravid (46 and 32%). In 1966 and 1968 more than half of the females were gravid (54 and 56%). If one takes into consideration the data of 1965 and 1967, it may be concluded that the grey whale females give birth once every two years, but the data from 1966 and 1968 permit one to assume that pregnancy occurs more frequently. In order to specially clarify this question, we carried out an analysis of the ovaries of 28 sexually mature females. Initially there was established the total number of ovulations, the corpora lutea traces were differentiated into the corpora lutea of pregnancy and of ovulation, and then a correlation was made of all of the ovulations and also of the number of pregnancies with the age. The possibility of differentiating the traces as belonging to corpora lutea of pregnancy or of ovulation was established by special examinations of the ovaries (Zimushko, in lit-t.). We will not stop to consider this question in greater detail here. 74

In Figure 3 is shown the relationship between the total number of ovulations, the number of traces of ovulation and also the number of pregnancies and the age. The curves were drawn according to the average values. The maximal number of ovulations (21) was noted.in a female 13.3 m in length, and in this same female there was noted the maximal number of traces of pregnancy - 7 (6 traces and one functioning corpus luteum of pregnancy). The large number of retained traces on the ovary provides a basis for assu- mi.ng that, as in other baleen whales, these are retained in the

grey whale for an extended period, if not for-the course of the whole life. The accumulation of traces of ovulation with growth of

the female occurs somewhat more intensively than do the traces

of pregnancy. It is evident that pregnancy follows ovulation

more frequently in the younger females. On the average, the

ratio of the number of traces of ovulation to the number of preg-

nancies in females 12.0 - 12.5 m in length comprised approximate-

ly 1 i 1, while in females 13.1 - 13..5 m in length this was 2.5 : 1. It might be of some interest to present a çomps.rison of

the average number of ovulations occurring in one year in young

females and in the females of older age groups. in v^ew of the

small number of females older than 12 - 13 years (24- 26 layers

in the plug) in our sample, we did not make such a comparison,

but calculated the average number for the group of females from

4-to 12 years of age (8- 24. layers in the plugs). In the old

females, which had several traces of corpora lutea on the ovaries,

it was not possible to precisely establish the fir.st ovulation. 75 tri,) /11 13 a a"- atfieyee zruceo 12 D fraativectegocdreckeogenmesuc7 eiee/7?e2 eaemeemocrneii /I C 8- irae1 o o e 0:1) 8

•ri ç 7

• (.1

Ix (1) (:1 3 Z 2

• ,, 1/ is a m /9 20 2/ 22 Z9 -24 - 1/4"cno cr7098 8 ytifeb/..r f7peoirerx • Number of layers in ear plugs Pm. 3. 3aBilcintocrh mmwmcna c.leRos oByozwril H 6e- pemenuocra OT BonacTa

Figure 3.- The relationship between the number of traces of ovulation and pregnancy and the age. * Legend: a - total number of ovulations b - number of traces of ovulation - number of pregnancies

This was possible only for those having one trace or for the primigravidae. Therefore, in determining the periodicity of ovulation we made certain assumptions. According to our materials, the females which had less than 8 layers in the plugs (up to 4 years of age) had not yet ovulated. As is evident from Table 1, the first ovulation is found at an age of 4-6 years (8- 12 layers in the plugs). We were not able to calculate what percentage of females ovulates for the first time at 4 years, and what percentage at 5 and 6 years, and therefore we accepted as a basis that all of the females first ovulated in the fifth year of life. Knowing the age of the animal and the total number of ovulations, it is possible to establish the 76 average number of ovulations occurring in one year. According to our materials, in the grey whale females aged from 4 to 12 years there occur on average approximately 1.4 ovulations per year. In establishing the cyclicity of calving there was made a comparison of the number of pregnancies with the age of the females. It became clear that within the population there are found females with different sexual cycles. Some females give birth after a year, while some reproduce every year, 2-3-4 times in a row. Between such series of pregnancies there are found annual or biennial intervals. There were found females which, after two or three pregnancies, periodically succeeding one another, subsequently gave birth after a year. In our sample, 40% of the females reproduced onoaevery two years, while 60% of the females reproduced 2-4 times in a row. It has already been mentioned above that young females become pregnant more frequently. The first ovulation, apparently, as a rule, terminates in a pregnancy. We noted only one female in which the first two ovulations did not terminate in pregnancy, while at the same time there were not infrequently noted females which had 1-2-3 traces of pregnancy on the ovaries and not a single trace of ovulation. Females that had given birth more than seven times were not encountered. Thus, in the grey whale population there are found females with different sexual cycles. Some doubt may arise as to whether the duration of the pregnancy is not a year, as has been accepted (and as we accepted as a basis for the calculations), but more or less than this. An analysis of the literature data 77

Table 2. Sizes of embryos of grey whales, cm.

T a 6 a u. a 2

Pa31ept.4 31.'14110110B CeplAX KIITOB, Cit • AB1 C „ D , l

June mmu, 105 July Hnu 10 116 185 137 Aug. Amycr 16 94 221 173 Sept.c enTsi_pbm 5 181 280 240 Oct • OKTa6pb 3 •301 374 340

A - Number of individuals measured B - Minimal size C - Maximal size

D - Average size

on the sizes of embryos (Andrews, 1 ,914; Tomilin, 1957) and of our data (Table 2) showed that the seasonal nature of mating in grey whales is expressed fairly clearly. There is no such great variation in the sizes of the embryos during one and the same month as is found, for example, in the fin whale (Zemskii, 1958). The smallest embryo had a length of 94 cm. Using the methods of S. Risting (1928) and B. A. Zenkovich (1937) for the calculation of the daily increment in growth of the embryos, we determined that this same small embryo was conceived in March. The fact that during the summer and autumn months no embryos were found in the initial stages of development may serve as a confirmation of the view that pregnancy lasts about a year, i.e. as was considered to be the case previously. By taking into consideration the ratio of males and fe- 51 males in the population and the number of sexually mature females participating in the reproduction, it is possible to establish 78

Table 3. The ratio of males and females of the.grey whale in the catches of 1965 - 1968, as J.

TaGaii ua 3 Cootaomeicxe caniim n caniox cepbIx xNTO3 s y.nouax 1995-1968 rr., % s A^u Sex no, 1965 1966 1967 19G8 aa 4 roza

FemaleT,aa^x3i 58 49 62 67 59 Males Canutt,i 42 51 38 33 41

A - Average of the 4• years.

the numbers of the progeny. Analyzing the data of a4. year

period (Table 3), we see that in the catches of 1965, 1967 and

1968 there was noted a'small predominance of females. In the

catch of 1966 the ratio of males to females was 4•9 -'51%9- i.e.

practically this may be considered as I j 1. We did not observe

any differentiation of the feeding grounds of the males and

females.

The ratio of sexually mature and immature females, ac-

cording to years, is shown in Table 4.

It should be noted that, in connection with the ban on

the catching of undersized specimens, there was noted a selec-

tivity of the whaling in 1966 and 1967. Therefore, in the

subsequent calculations we based ourselves on the materials

from 1965. According to preliminary data (Zimushko, 1969), the num-

ber of new progeny each year was.determined by us to be approxi-

mately 23%. The final analysis of the materials permitted us to

make this figure more precise. It was found to be somewhat 79

Table 4. j The ratio of sexually mature and immature females of the grey whale, as %.

T a 6 It it a 4

CooTtionJoule nonorso3pu1Lx H uenonoBo3pe1 tAx camoK cepLax HHT013, % Sexually -Sexually rub, jienol0003peAlle n.e .„ Years immature ma ure . 42 54 1965 75 1966 25 196-; 28 72 67 . B cpcnitem 33 3 roita 33 3 year average

lower. If one takes into consideration that each year 60% of the sexually mature females reproduce (as was established on the basis of the ovaries), then the value of the annual increment of progeny comprises about 18%. It should be stipulated that these data make no pretense of being absolutely reliable. As more extensive material is accumulated, the investigations on this topic will be continued.

CONCLUSIONS

This paper was written on the basis of materia/s from 1965 - 1968, collected by the author in coastal settlements in Chukotka. In it is considered the question of the period of onset of sexual maturity of the grey whales and some data on their reproduction are presented. It was established that the grey whales start to participate in reproduction in the fifth to sixth year of life, having 8 - 11 layers in their ear plugs. 80

C) An analysis of the ovaries showed that in the younger females pregnancy ocurs more frequently after ovulation, than is the case in the older females. Evidently, the first ovulation, as a rule, terminates in pregnancy. There was noted only one female in which the first two ovulations did not terminate in pregnancy, but not infrequently there were found females which had up to three traces of pregnancy and not a single trace of ovulation. In other words, even the first three ovulations may terminate in pregnancy. The maximal number of traces of corpora lutea was 21% the maximal number of pregnancies was 7. In the females aged 4 to 12 years there occurred on average approximately 1.4 ovulations per year. In establishing the cyclicity of calving it was determined that about 40% of the females give birth after a year and about 60% reproduce each year 2-3-4 times in a row. In the latter, between such series of pregnancies there were found annual or biennial intervals. The ratio of males to females in the catches, averaged over 4 years (1965-1968), comprised 41 s 59%. The value of the yearly increment in progeny comprised about 18%. 81

REFERENCES

JII'iTEPA1'YPA

ApKTlIKIt. Tpya-bl ApKTIt^1CCKO- 1 Buxozpaôoa M. Il. r;4op eKlle Af:tel:onnraloul•lle ra rnlcTnryTa, T. 202, M.-JI.,- 1949. y dt tnnana AllTapKTIIKI[. 2 3e.ucrcurï B. A. Otlpe;te.venlle c IeRorr :ICezTbix TeJr ► Tp 'itl,t BI IIIPO, T. 33, M., 1958. npOJ10.Ii(nTC16fIOCTIr }K131111 c;lnnna:Ia il nepnoAnKe nx pa3- ^j 3e.ucrcut"c B. A. O nponmlczy niopcKltx nt.aexonnTalo- ruloa.ennsl. Tpyn1,I coneulalilui rio qKO.-lorlul il u!^} 'x. 113A-Bo AH CCCP, 'Ni., 1961. Ente o cePOiNr 1calllti)opnltÎlcrionl K1rTe. C.BCCTI1nK Z(a7blIenocT. 3eHt.oQUU Ti. A. cjinanaan AI I CCCP», \°z 23, 1937. 1-IexoTOpl,le naurlble no 611ororrm ceporo KrITa. C6. «MopcKrle 5 3u:rt/urno B. B. nrnçKoluITaloutnc», ri., r.HayKa», 1969. ^nto>Kennl0 cepblx rrlTOn. Te3nc1,1 IV Bce- b 3u.tr!Iur;to B. B. MaTepuumt,l no pa3N c0103110ro conellianllA no 113y11elnno 10pcrn.\ D1ieKOnnTalOn(nX. t^l., 1969. M. B. K nonf,ocy 0 unK.ne pa3Muo}Kenilsl a)lnlnanol3• 7Kfaurno A. H., 11r7aururt AIITapICTnI:I:. (B, physalis) il rop6:l•rl,l\ lilrron (iNI. noClosa) aTJ1aIIT111lecKOro ceKTopa 3oonor. :ICyplla.1, T. 38, nt,ln. I, 19:,9. Cn6. oTA. AH CCCP, 1-Ionoc1161rpcK, 8(7,Inxuttcr;uil H. A. filloale'rpnil. 113R-no l')fil. 3nO:IlOqnA xcn- 9 Cellepr{oEJ C. A. Tîn1a111IfCa Ilace.le7infl Il npncnocO6lrTe:I6n1.E lorntax. 1'l-;R-DoiTi-no AI-1 CCCP, A1.-JL, 1941. Cepi,Iït KuT n,Iarynax nocrOllnoro no6epexcbA cpeAneïl =IacTlr ^ a 7'o:uimuK A. F. plmrona ntopa. «Ilpnpo:â», ?^_• 7, 1937. T. IX, ccp. «3aepn CCCP ti npnne>Kaùutx ÎÏ Tonu:nutc A. F. K1:T006pa3111,iC. . 1 t311-no AI-1 CCCP, Al., 1957. cr Ial! » Taloullle 4tl^^ynlt ],^ l/aru^t;uir K. /l. I^nrooGpaanl>lc n ,^cronorne. C6. cM Icronn CP», T. 2, 1'13^-uo AI-i CCCP, M.-JI., 1963. J. Ricc D. W. NI-I'I', 52, no 7, 1963. Â ndrelris R. C. The California ^,ray whale, Memoires of the American Museum f atr:ral History, New Series vol I, 1914. Ristirb S. Whales and ^+•ha!c Foaillscs, Rapp. Cons. Explor._i^tçr, vol. 50, 1928. M. The Marine Mammals of Northwestern cosat of North Î Scarrur7on C. America. San Francisco. 1874.

1. Vinogradov M. P. Marine mammals of the Arctic. Trudy Arkticheskogo.instituta (Transactions of the Arctic Institute ), vol. 202, Moscow - Leningrad, 194•9.

2. Zemskii V. A. Determination of the traces of corpora lutea

in the fin whale of the Antarctic. Trudy VNIRO (Trans-

actions of the All-Union Research Institute of Marine

Fisheries and Oceanography), vol. 33, Moscow, 1958-

3- Zemskii V. A. The life span of fin whales and the periodicity of their reproduction. Trudy soveshchaniya po

ékologii i. promyslu morskikh mlekopitayushchikh (Trans-

actions of the conference on the ecology and exploitation

of marine mammals). Publ. USSR Academy of Sciences,

Moscow, 1961. 82

4. Zenkovich B. A. Further information on the California grey whale. "Vestnik Darnevostochnogo filiala AN SSSR" ("Reports of the Far-eastern Branch of the USSR Academy of Sciences"), No. 23, 1927. 5. Zimushko V. V. Some data on the biology of the grey whale. Symp. "Marine mammals", Moscow, "Nauka", 1969. 6. Zimushko V. V. Information on the reproduction of grey whales. Tezisy IV Vse-soyuznogo soveshchaniya po izucheniyu morskikh mlekopitayushchikh (Reports of IVth Ail- Union conference on the study of marine mammals). Moscow, 1969. 7.. Kulikov A. N. and Ivashin M. V. Contribution to the question of the reproductive cycle of the fin whales (B. Phvsalis) and humpback whales (M. nodosa) in the Atlantic sector of the Antarctic. Zooiogicheskii zhurnal (Zoolo- gical Journal), vol. 38, No. 1, 1959. 8. Plokhinskii N. A. Biometrics. Publ. Siberian Section of the USSR Academy of Sciences, Novosibirsk, 1961. 9. Severtsov S. A. Population dynamics and adaptive evolution of animals. Publ. USSR Academy of Sciences, Moscow - Leningrad, 1941. 10. Tomilin A. G. The grey whale in the lagoons on the eastern coast of the central portion of the Bering Sea. "Priroda" ("Nature"), No. 7, 1937. 11. Tomilin A. G. Cetaceans. vol. IX, ser. "Zveri SSSR i pri- lezhashchikh str:an" ("Wild animals of the USSR and adjacent lands"). Publ. USSR Acad. Sci., Moscow, 1957. 12. Chapskii K. K. Cetaceans and pinnipeds. Symp. "Mammals of the Fauna of the USSR", vol. 2, Publ. USSR Academy of Sciences, Moscow - Leningrad, 1963. 83

UDC 599.532 V. L. Yukhov

SOME DATA ON THE FEEDING OF SPERM WHALES IN THE HIGH LATITUDES OF THE ANTARCTIC

Our investigations on the biology and distribution of the antarctic toothfish (Dissostichus mawsonii Norm.) were carried out on material obtained from the stomachs of sperm whales during a study of their feeding (Phvseter catedon). At the present time this method is the most effective one, since other possibilities for studying the antarctic toothfish in the open ocean are not available at present. The absolute length of the examined fish ranged from 132 to 174 cm, while their weight ranged from 20 to 70 kg. All of the examined toothfish were in a satisfactory condition, and the sites of their finding corresponded to the cited coordinates of the sites of catch of the sperm whales. The observations were carried out on the whaling base "Sovetskaya Ukraina" from 1965 to 1969. As is evident from the schematic map (Figure 1), the toothfish, in addition to their circular distribution (A. P. Andriyashev, 1964), accomplish considerable migrations in the latitudinal direction. The northern border of the distribution of the toothfish, according to our data, is the zone adjacent to 57-58° lat. S., i.e. the northern border of the massive appearance of the adult forms of the antarctic krill (Emphausia superba Dana) in the Antarctic. 84

On the basis of the studies which were carried out we came to the conclusion that the antarctic toothfish, or more precisely its adult forms, are common in the pelagic zone. According to our data they are found far from the Antarctic continent and islands in the open portions and over great depths of the Southern Ocean during the course of the entire summer of the Southern hemisphere. The character of the feeding of D. mawsoni may be judged by the materials obtained by us in dissections of 22 stomachs of these fish (Tables 1 and 2). The dissections of the stomachs of toothfish, obtained at various periods of the antarctic summer over a huge expanse of water in the high latitudes of the Southern Ocean, showed that their food spectrum was fairly limited in both the meridional and latitudinal directions and was composed almost exclusively of small forms of cephalopods. The stomachs of the toothfish examined by us, in which the degree of filling was slight, contained up to 50 mandibles of small cephalopods, which corresponded to 25 ingested squid. Besides the beaks, in the stomachs of the toothfish there were found many pieces of tentacles and arms, crystalline lenses of 55 the eyes and from 300 to 600 gui of spermatophores, belonging to small cephalopods. Sometimes the stomach of a toothfish contained up to 130 maneibles together with other remains of cephalopods. The large amount of remains of small cephalopods, found in the stomachs of the antarctic toothfish, indicates, on the one hand, an electivity, i.e. a preferred selection of the type of foodi on the other hand, it may be assumed that in the regions

30• W 0 E 30° ,

•,, o' 60° 4IIIIII• A() '1) e, • o ,/ 90%,/ 1 kffenkle \\e) 90"E _ANTARCTICA e 0 e0 PrtiOPE

120' 120°

150. W 10 E 150°

Pnc. 1. Pacnpocrpanenne D. niawsoni n An-rapimme no nrecHnam: • —sumapb; 2— 4mnpa,lb, 3— maim'

Figure 1. The distribution of D. mawsoni in the Antarctic according to months,

1 - January; 2 - February; 3 - March.

A - Weddell Sea B - Drake Passage C - Ross Sea

of the highly productive krill zone there live large numbers of small forms of cephalopods, which live in schools. The data on the distribution of the toothfish is presented only for those examined with respect to their feeding. By comparison of the food objects of the sperm whales in the oceanic zone under consideration mitheebm with the food of the toothfish, it may be ascertained that these are different. 57

Table 1. Stomach contents of antarctic toothfish (D. mawsoni) in January.

T 6.1 .111.1 1 Coaepuomoc eeng,KoB anTapicottlectutx tcabtxaveii (D. mawsoni) u stnaape . .

CoReplicitmoe xe.elve,Hoti latitude longitude Stomach contents

57°05' to. w. S. 70°19' B. 21. E. aOcTaThit ronouottorwx: xpycraatwit r.qa3, cueptaToq)opt.t. H.)- 313011101, xpycTaanun VJIO3 me..wax pie) 570331 to. in. 75°32' B. R. E. bIlycTo 600 18' to. In. 23°56' 3. A. W FlycTo 6030' to. In. 35°24' 3. du.W Flyer° 61°10' 10. 111. 94°00' B. ,B. E. IlycTo 61°15' nt. 61°05' 3. A. W nycm 63°30' to. In. .166°30' 0. J.L. E. COcraTKIt ronoBouorux: o6pb1t3Iit myna. ,aeu, pyg, cneptaTocItopbt, : ■tattawv ,111 e°30' 10. nx. 108°21' 3. A. W • Olt OcTaTwt rozoBonornx: 1+.1a11.1116.V.11.1, CllepMaT0410pb1, xpycraatwit roaa 137°40' to. In. 124°55' 3. R. Itel • e 0211111 ne6osnauoii Rastbmap ue.runioN: n r0.10130110111X B 131Iae mama- ' 6y.a, wyna.nen,, cneptaTocitop, xpycra.. ma3 69°25' 175°35' u. E. I 06plamm wynaaeu, manu,n6y.-ibt, citep• maTocitopht, xpycramwit rita3 M1-2,11-;BX ronoBonorlix

a - Remains of cephalopodss mandibles, crystalline lenses of eyes, spermatophores. Vertebrae and crystalline lenses of eyes of small fishes. b - Empty o - Remains of cephalopods: pieces of tentacles, arms, spermatophores, mandibles. d - Remains of cephalopods: mandibles, spermatophores, crystalline lenses of eyes. e One small entire squid and the remains of cephalopods in the form of mandibles, tentacles, spermatophores and crystalline lenses of eyes. f - Pieces of tentacles, mandibles, spermatophores, crystalline lenses of the eyes of small cephalopods.

While the length of the mantles of the cephalopods consumed by the sperm whales ranged from 60 to 180 cm, the length of the spermatophores ranged up. to 25 cm and the length of the pharyngeal plate of the ventral mandible - up to 6.2 cm and more; in the squids consumed by the toothfish the length of the mantles did not exceed 33 cm, with a spermatophore length of 3.5 to 7 cm. 87

Table 2. Stomach contents of antarctic toothfish (D. mawsoni) in February.

TaGnitüa 2 'CoAep,,Kndroe HcenyAKoa aI1TapKTItYeCKirx KJIbIKaNCÎi (D. mawsoni) a(j,enpane

CCTO Ao0'1.T4 q Stomach contents a i! ua e ^ on^i,^u e CoaepKUn+oe :!:eA}ason p

61'1 7' 10. 111. ,S • 152°02' 3. A. ^,^}j . ^yCTO 62°36' io. w. 147°38' 3. A. ^Y • Canlenb 65°53' lo. w. ,171°05' 13. A.E. COCTaTr.u ro:ronoltorrtx n !xaa n(,so.v,- wrtx Kajibmapa ilelrlKOm 66°38' 10. iii. 149°39' 3. A. W . dOZnn ueah!it r:a7bArap, Kanlenb, OCTaT- Kn ro.7onotrorn 66°40' 10. m. 149°3b' 3. A.W.' eOcTaTK31 ro.zor:ônorl(x: a(au;1u6y:m. cncpalaTOCj)oplar, 06pbinKn pyK, xp^•CT:r ,nnKrl rna3 -67°03' lo. m. 116'20" 3. A. W • bl(a^ter!b :67°20' 10. ni. 175°05' n. A. E . fOcTaTKU roaononorux: uauu6y:!1,( 68°00' IO. llI. 155°'16' 3. À. W W. CTdTKI( ro70IIDIlOrIIx: Jr^111i1!!Ü1':!11, crtep;raTod)opbt, spVcTam!KU r:!as 68°15' jo. In. 177°32' 3. A. W . hOCTaTKII r0.'106OftOrnS: O6pidnK!1 pp;, 111yn£17C11, \pyCTaj7nKIl r.7a3, \1a11,111tiC- JIUr, cnep\faTOq)Opr,r 68°42' 10. Ili. '173°36' Il. ;t. W. lOCTa7 KI[ roA0nO1(orI[x: m[I ll;ln6\': iI1 68°,16' Io. Ili. 153°iU' 3. R. YY • a>lenb - 67°00' IO. 111. 111°14' 3. il. W. JO_Ikl(II ria3b9rap, OCTaTÜI! \rC.1!üf`: r 0,10• , norrornx

a - Empty b - Stone c- Rema' ins of cephalopods.and two small entire squids. d - One entire squid, stone, remains of cephalopods. e - Remains of cephalopodss mandibles, spermatophores, pieces of arms, eye lenses. f - Remains of cephal.opodss ' mandiblPs. g - Remains of cephalopods: mandibles, spermatophores, eye lensès. h - Remains of cephalopodss pieces of arms, tentacles, eye lenses, mandibles, spermatophores. i- Remains of cephalopodss mandibies. j - One squid, remains of small cephalopods.

and a length of the pharyngeal plate of the ventral mandible of from 1.2 to 1.7 cm.

Sometimes in the stomach of the toothfish, together with the remains of cephalopods, there were found almost entire, recently consumed squids. Generally the mantle length of such squids ranged from 20 to 33 cm, while their weight ranged from 88

200 to 1100 gm. Thus, for example, in the stomach of a toothfish (absolute length 1k5 cm, weight 39.7 kg), in addition to the remains of small cephalopods weighing 450 gm, there were found two small squids in a satisfactory state of preservation. The total length of one of these was 56 cm, mantle length 26 cm, arm length 14 cm, tentacle length 24 cm and weight 200 gin. The total length of the second squid was 72 cm, mantle length 36 cm, arm length 21 cm, tentacle length 31 cm and weight 270 gin. In all, the stomach of this toothfish, which was a little more than half full, contained 920 gin of food. Small forms of cephalopods or their remains were found by us in the stomachs of the analyzed fish, caught over the huge expanse of water in January, February and March. At the same time, the stomachs of the sperm whales almost never contained the forms of cephalopods that were found in the stomachs of the toothfish. Apparently, the small forms of cephalopods live in different horizons than do thosesquids on which the sperm whales mainly feed. It cannot be excluded that the group of consumers of the small cephalopods in the Antarctic (antarctic toothfish, pinnipeds„ dolphins, birds, larger forms of cephalopods) can indicate to us the horizons where these species are concentrated during this or that period. Small squids are found in the stomachs of the toothfish at both the beginning and the end of the summer in the Southern hemisphere. Thus, in the stomach of a toothfish (absolute length 1)4.1 cm, weight 34 kg), examined in March, there were found cephalopods. The length of the mantle of one of the least digested of the squids, which were removed from the stomach of the fish, was 33 cm, with a width of 11.5 cm, while the length and width 89 of the cordiform fin was 20 X 24 cm. The weight of the remains of this squid was 650 gin. The ink sac was filled with a dark brown liquid. It may be mentioned incidentally that in the stomach of the examined whale, in addition to the toothfish, there was found a specimen of a rudderfish (Icichthys australis Haedrich, 1967) which had not previously been indicated for this region. This was 55 cm in length, with a weight of 2500 gin. Worthy of attention are the cases of finding small stones in the stomachs of the toothfish (Table 3). As follows from the data presented, the percentage frequency of occurrence of stones is considerable (18.2%). The size of the stones varied; for example, the length and width of one of these equaled 2.5 X 1.7 cm, with a weight of 7.5 gin. In a second case the dimensions of the stone were 3.6 X 3.0 cm, with a weight of 26.4 gin. It may be supposed that the stones get into the stomach of the toothfish accidentally. Finally, of some interest is the case of the finding of a small number of small vertebrae and crystalline lenses of eyes belonging to small bathypelagic fishes. The remains of the fishes in the stomach of the toothfish were recorded together with the remains of small cephalopods, at 57 ° 05' lat. S. - 70° 19' long. E. The length of the vertebrae of the bathypelagic fishes was 0.4 cm, while the length of the spermatophores of the cephalopods was 7.0 cm. Thus, as is evident from the indices presented, the qualitative composition of the food of the toothfish is not only uniform but scarcely changes at all in time or in space. The 90

Table 3. Components of the food in the stomachs of toothfish

TaG:IUua 3

KoMnolienTbt n{tU(n B )KeAyJiKa% KJIbIxaReFi

Kounonenrm Konn tecrno Components Number

a- Ka.7b\faPbl 11711 IIX OC' 12 54,G TaTKII b QCTaTIill PbIÛ C xanbiMa 4,5 paNnt c Kamin 4 18,2 d nyCTo 5 22,7 e Eeero 22 100,0

a - Squids or their remains b - Remains of fishes with squids c - Stones d - Empty e - Total i toothfish feeds preferentially on s.nall forms of cephalopods, while the small bathypelagic ichthyofauna is not of important

significance in its feeding.

Furthermore, and this is most probable, the vertebrae

of the small fishes may have got into the stomach of the tooth-

fish from the stomach of a squid, which had fed on the small

fish and had in turn been consumed by the toothfish. In this

connection it should be noted that the stomachs of squids in

all sectors of the Antarctic are always full of the remains of

small bathypelagic fishes in the form of vertebrae, otoliths,

eye lenses, scales etc.

As to the small bathypelagic fishes, the abundant deve-

lopment of the krill attracts these into the surface layers,

where they feed intensively. The representatives of the small 91

bathypelagic ichthyofaunal which were removed by us from the stomachs of the baleen whales, contained in their own stomachs from 7 to 45 specimens of E. superba Dana. Feeding on krill, the small fishes serve as prey for the cephalopods, which in their turn are consumed by the toothfish, which apparently move up from time to time into the surface horizons. These, together with the cephalopods, comprise 59 the food objects for a "predator" of higher rank - the sperm whale.

• REFERENCES

JWITEP.ATYPA A. 17. 063op (1)ayilur pie() Airrapwrmat. liccaeaonanag cbayilbt mo- Anaptuuaeo airrapKrittiec- pefi, 11 (X). Pe3y.tIbT8Tbl 6110.TIOrI1'ICCKIIX ttccaeRonalutil COBeTCKOrt 1<05 3Kcile;utunit (1955-1958 rr.) M., «flayia», 1964.

1. Andriyashev A. P. Review of the fish fauna of the Antarctic. Studies on the fauna of the seas, 11 (X). The results of biological studies by the Soviet Antarctic Expedition (1955 - 1958). Moscow, "Nauka", 1964. 92

UDC 599.535 L. eedvedev

INFORMATION ON THE FEEDING OF THE BELUGA IN THE DIKSON REGION 60

Spending a great part of their lives in the almost in- accessible parts of the Arctic Ocean, where fisheries and the commercial exploitation of marine animais is not developed, the belugas actively accumulate during the process of their feeding those natural reserves of food materials which cannot be caught by man and so give us the opportunity of utilizing these reserves, since the beluga itself is an object of commercial exploitation. Also deserving attention is the effect of the beluga on the fish stocks: is it injurious in fishery regions with valuable species of fishes, in particular to the whitefish fishery in the Kara Sea? The information on the feeding of the beluga, collected by us in 1961 - 1963, refers entirely to the summer period of its life and was collected in the very compressed period of the industry: in August and the first ten days of September, with the most detailed collections being carried out in 1962 and 1963 (Table 1). In the animais dissections were made of the oesophagus and the first section of the stomach, i.e. where the food remains are retained. In the following sections of the stomach there is found only a small amount of a green-brown liquid, which is, apparently, the remains of the completely digested food. In the intestine the remains of the chyle were found. 93

Table 1. Results Of dissections of the stomachs of belugas in August of 1962 (near the Uboynaya river).

Ta6nttqa 1 1 Pe3ynt,iart,t ncxpt,tTUn .KenyAKoe y 6enyxtt n aerycie 1262 rua (y pctttt Yboiittoii)

L9cKp ro I B ilycrntX CC coucp^tutntwnt ^C a;t+atro^rsro Bo3pacniwc rpyuot^t Nceny,,KOU t a a I Aroups l I I ( V„ xoauv. qb

Benwe White 80 62 78,0 8 10,0 L(t:eTttweColOUr d 37 26 70,0 11 30,0 Ctttttie Blue 9 3 33,4 6 66,6

Bcero Totall 12G 1 91 I 72,01 25 1 20,01 10 I 7,9

A - Stomachs dissected B -- Empty C - With contents D - With liquid a - number

During all of the seasons of the .study there was noted a large number of empty stomachso Thus, of the 136 stomachs examined during the 1961'season 130, or 96%, were found to be empty.

The phenomenon of empty stomachs occurring in massive 61 numbers may be explained by the following factors: 1. Rapidity of digestion of the food.

2. State at the moment of catch - "migration" or

"fattening".

3. Regurgitation of the food at the time of the kill.

In connection with our sections of the fishery (the river Uboynaya, the Kamennyy Islands), the second case is the most probable one, namely "migration". The belugas were not infrequently dissected one and a half to two hours after the kill, so that the food could not have been completely digested. 914,

Table 2. 7-- Results of dissections of the stomachs of beluga from August 21st - 30th in 1963 (near the Uboynaya river).

• T a 6 a II It a 2 Peayabrana BcKpbrraa liœ.nyp,Kon y 6e.nyxn 21-30 aarycTa 1963 rOp,a (y pelui

I witp contents i . Beicpbt- ! pbe paKo- ■ Bospacraue TO ori pa3um e, rpy[11114 Azulye, Pmea 1 Age ton. 96 . f1Sh Boaopoca it mllk Sex e no. no 4 no. groups ir 96 e0.1. .0. 9.;

heohie 33 9 1 64,0 4 12,0 94,0 W 11 5 46,0 9 18,0 36,0 BCTIlble camub 11 7 64,0 18,0 2 18,0 . Cdoure cammt 8 4 50,0 2 25,0 2 25,0 Cnnlle ca 5 20,0 4 80,0 Blue camR4 2 50,0 1 50,0

Emro CZ-11%111bl 49 29 60,0 6 12,0 W 20,0 4 8,0 Total camm 21 10 47,0 4 19,0 6 29,0 1 5,0 39 I 14,0 W MA 5 7,0 41togetherBcero M 56,0 10 A - Stomachs dissected B - fish, crustaceans, algae m - male f - female no. - number

• Regurgitation of the food (except for milk in the suckling animals) was never noted, even once, although there is ,information from professional hunters that in the Gulf of Ob and especially at Dikson this phenomenon has been observed on more than one occasion: in July-August the stomach in the dresSed animal is sometimes filled with arctic cod and smelt, which are also regurgitated during the kill and when the stomach is compressed at the moment when the beluga is dragged up onto the shore. 95

In 1962 it was impossible to characterize in detail the composition of the food, because of the negligible amount of remains. Therefore all of the data were divided according to groups: 1. Stomach empty. 2. Stomach with contents, including all cases of the finding of food remains. 3. Stomach with liquid. In 1963 the material was collected in an even more con- densed period, but in greater detail (Table 2). Information on the feeding of the beluga in the Dikson 62 region has been reported by V. G. Geptner (1930), A. A. Kirpi- chnikov (1937), S. K. Klumov (1939) and M. N. Tarasevich (1962, 1964). All the authors indicate that the main objecte of feeding are small schooling fish (mainly arctic cod), to a lesser extent - large schooling fish, and to a still lesser extent - non-fish objects: crustaceans, molluscs, coelenterates and algae. The latest reports (S. E. Kleinenberg et al., 1964; M. N. Tarasevich, 1962) on the results of collections at Dikson in August-September 1957 and in September 1958 present the following data: serving as food for the beluga at Dikson are arctic cod, omul, arctic cod*, smelt, crustaceans, molluscs. Our data are basically similar to those presented above, though remains of large fish and molluscs were never found by us; evidently these are accidental components of the qualitative spectrum. According to the data from 1962-1963, the feeding

* Translator's note. "polyarnaya treska" "arctic cod", according to W. E. Ricker and other sources this is an alternative name for "saika" (Boreogadus saida), which is mentioned as the first item in the above list and elsewhere in this paper. Pos- sibly, by "polyarnaya treska", the author is referring here to the polar cod (Arctogadus glacialis). 96

objects that were found in the stomachs of the white animals comrised (as percentages): Fish Crustaceans Algae (arctic cod) Mysids Gammarids green 50 8 12 30 Çonsequently, in the region of the Uboynaya river the feeding objects of the beluga consist mainly of fish, and to a lesserdegree of algae and crustaceans. Among the crustaceans found the majority were gammarids (side-swimmers), which may also have been consumed with the fish. The presence of the green algae may be explained by the change in the feeding spectrum of the beluga on account of the poor development of the fish food base in 1963. In addition, in the stomachs of the belugas in 1963 there were noted small amounts of sand and pebbles. It may be assumed that during this season the beluga reached to the bottom in its search for food.

In comparing the qualitative and quantitative COMDOSi- , ti.on of the food of the beluga in 1962 and 1963, we see that in 1963 the belugas fed more actively, though in their food spectrum there appeared a greater number of non-fish objects. This ineeates that in 1963 there was a poorer development of the main food base, QOelenterates were never found by us, even on a single occasion. One may agree with the opinion of S. K. Klumov (1939) that these organisms, in the body of which there is more than 90% water, cannot be food for the beluga, in contrast to the 0 opinion of V. G. Geptner (1930), that the beluga feeds on cteno- • phores. The appearance of ctenophores and medusae is favoured 97

by particular changes in the hydrometeorological conditions, which are at the same time favourable to fishes and, through the latter, to a concentration of the belugas. Consequently, the development of invertebrate fauna may signal a mass approach of this animal. The character of the migration of the beluga near the Uboynaya river depends on its feeding in this region. Near the mouth of the Uboynaya, situated 60 km to the east of Dikson„ the commercial beluga moves to the west to the "Dikson feeding grounds", and the feeding near the Uboynaya river may be of a random character, in connection with the random nature of the fish concentrations that are accessible to the beluga in this place. However, there is no doubt as to the existence of feeding areas near Dikson, particularly since the professional hunters from the Archangel schooners, who conduct their whaling near Dikson, state that the animals "came from different directions but towards one place". Of the schools studied by us off the Uboynaya river, only two, taken on the 21st and 27th of August in 1963, had the remains of semi-digested fish in their stomachs. Both schools were relatively large (60 and 44 head respectively). They moved slowly and behaved very placidly, while most of the other schools had a characteristically restless behaviour and were easily frightened. Generally, because of this, penning was carried out with difficulty, but these two schools were taken in their entirety and at first the belugas paid no attention to the pur- suit, which is characteristic of feeding animals. 9 8

The echogram of a scouting ship, which was searching for aggregations of arctic cod off the mouth of the Uboynaya, on the 21st of August showed the presence of an aggregation of fish close to shore. The appearance of the second feeding (as it seems to us) school of beluga was preceeded by warm and calm days on the 26th and 27th of August, when there were noted many medusae and ctenophores. Probably, the delay in the break-up of the ice near the shore close to the Uboynaya river induced a concentration of the arctic cod for a short period; the fish could have moved up from the open sea and lingered in the section where the ice was intensively thawing. The observations in 1973 showed the irregularity of the feeding by the beluga off the Uboynaya river. In just the same way as the concentrations of arctic cod into dense schools, suitable for the feeding of the beluga, are random occurrences in this locality, so also in this region the encounters of the beluga with the arctic cod are random occurrences. It should be noted that the animal which we encountered amidst the ice in the open sea, according to all indications, was not feeding (off the Kamennyy Islands). However, even though the feeding near the Uboynaya river is of a random character, there exists the possibility of a concentration of the food objects and of intensive, though temporary, feeding. The fact that remains of recently ingested arctic cod were not found in the stomachs of all animals indicates that the concentration of this fish was relatively slight, although it might also have been dense. 99

Table 3. Components of the food in 1962-1963 (in absolu-te values).

T a 6.n H Lt a 3 IÇONinifilein-1.1 minim Is 1962-1963 roa,ax (B 26C0J110T1ILIX Be.911t11111aX)

Components KOM11011121111,1

Bo3r....rfflna int6a prieno6pormue .eopoc.in fie-- =Lib tceanw algue Age group 1962 -1 1963 1962 I 1963 1962 j 1983

Benbie White 4 14 6 2 9 Coloure L17 9 2 1

BœroTotal I 11 23 I 8 2 ' 10

In 1962- 1963 no qualitative or quantitative changes in the feeding of the beluga at different times of the day were found. The feeding spectrum in the adult (white) animals is more complex than in the young (coloured) animals, especially in the males, though differences in the feeding of the sexes wre not noted (Table 3). Particular attention should be paid to the question of the feeding of females in relation to their physiological state. According to the data from 1962- 1963, it was noted that no significant differences were observed in the numbers of empty stomachs in females of different ages and, consequently, in sexually mature and immature females. This is understandable, if it is takmaxixtu considered that the periods of calving and rutting were essentially completed and all of the females were feeding intensively, or that a decrease in the intensity of feeding is connected with the beginning and end of reproduction. 100 .

Table 4. Components of the food in the different sexes (adult individuals, according to the data of 1962 -1963)9 /

T_- Gzl:ua. 4 KflrtnwteaT.w PH= y pas:IHVabrx HOJIOB (n3poc.nhIe oco6a, no.AaIIIIbIm 1962-1963 roAon), %

C omp onent s Ko+mo1teunil 11on f ip crus zaceans, aga^ Sex Pu p.^.i:ooupaant+c oonn cn^

caULibl) Males5 20 30

car,r,,I Female 1'B 31

In the males, during the period of the whaling, the.

"peak" of the rutting had also essentially passed and they were feeding in a manner identical to the sexually immature

animals and thefemales ( Table 4•).

The pattern of feeding with age, which was proposed by

V. A. Arsen'ev (1937) for the far-eastern beluga: Blue Grey Pale blue .White

Yd 1k Crustaceans Fish Fish

Fish Crustaceans was not confirmed in our regions. This scheme.is probably more 65 characteristic of the far-eastern beluga. The Kara Sea is poorer

in crustaceans and the animals immediately change over to feeding

on fish, while crustaceans serve as incidental supplementary

food. Judging by the otoliths, of which in 1963 there were

found from 50 to 600 in a single stomach, which comprises up to

300 specimens of arctic cod with an average weight of 60 gm, in

the food of the beluga there may be 15 - 20 kg of the fish, though 101 ii

,. .

it is not known whether we are here dealing with the remains of

fish consumed in one mea1, over the course of one day or over

several days. It was also not established how frequently the beluga feed in the course of a day. Nevertheless, however many

fish the beluga consumed, it cannot be considered as an enemy

of the fishing industry in the Kara Sea, since the valuable

species of Kara fishes do not form sizeable industrial a.ggrega-

tions, with the exception of individual sections of the Gulf of

Ob, where the muksun* is caught. On the contrary, there exists

the opinion (Valikov, 1935) that in the muksun fishing in the

Gulf of Ob and in the lower reaches of the Ob the fish escape

from the beluga into the shallow areas, where they are inacces-

sible to this animal and where the work of the fisherman is • facilit ate.A. What were the conditions of the approach of the beluga

in 1963 and why was the feeding in this year different from

that in 1962? The basis of.the active approach of the beluga to the

Ob - Yenisey northern sector is the character of the winter and

summer: after a cold, long winter in a moder_ate-summer there follows an inactive approach of the animals, as was shown by

comparisons of the approaches of the'belugas in different years

(Tarasevich, 1960). Consequently, the severe winter of 1962-1963 changed the

qualitative and quantitative composition of the belugas, which

was reflected in the distribution of the migration sectors, the,

periods of the approach and also the periods of reproductions

the rutting of the beluga in 1963 was somewhat delayed. The

jE Translators note. muksun - ,,,re^_-onuso muksun• 102 thickness of the fat layer was also diminished: the change in the feeding had affected the degree of fattening. All of this had played a role in the marked deterioration of the results of this industry in 1963. It should be added that in the summer of 1963 close to the mouths of the Ob and Yenisey belugas were noted more frequently and in larger numbers than in the preceeding years; probably the animals were proceeding to places with a direct fluvial run-off. It is necessary to take this factor into consideration in the selection of of whaling sectors in the case of an unfavourable, depending on the natural conditions, prognosis of approach.

CONCLUSIONS

In the sector off the Uboynaya river the main food of the beluga consists of small schooling fish (arctic cod), algae and crustaceans. The minixamtmexmfx±km feeding of the beluga off the Uboy- naya river is of a random charcater, since the approaches of the fish themselves is also random in nature. In the Kara Sea the beluga does not cause great harm to 66 the stocks of valuable commerciarfishes. The severe winter of 1962-1963 caused the poor development of the main food base and induced the beluga to feed more actively in places with a small content of fishes, and also increased the significance of non-fish objects in the food spectrum of the animal. 1 03

REFERENCES

JIHTEPATYPA

1 Apcenea B. A. He1m-L.0rue ,i&auiiiie o unTattun 6enyxn. Hooecnta T1'i1-11 30, • -IMO, 1937. fenritep B. I'. MaTeptiaabt 110311B111110 reorpaclumecuoro pacripe.leaeunn u • 151100011111 CiCnyXII. Tpy1Ih1 111114 300:101111t npu mry, T. 4, BbW. 2, 1930. `. 3 Knednetttiepe C. E., 5/41101:013 A. B., BeAblWeilq B. M., rapaceelvi M. H, Be- xa. 011bIT mottorpiulintlecNoro itemeRona nun nuRa. M., «H a yKa», 1964. Kity.itoo C. K. Benyxa Cone-mm[0 Cotooa (cbtpbeaan 6aaa n npomblee.-1). Tpy- jul BIMPO, T. 12, 1939. D Kupnututtuwe A. A. lia6.moi.lenitg uaj opcginui m:teRonturounnumn B 101"0- LIOSTO%1BOrf guilt KopeKoro moon. 1310.1.1CTC111, IN'i01111, OT;1.. 6110.11011111, UM. 4,1937, . 7'apaceeitu M. H. 3auottomeptiocTit noxo,aa 6enyxtt K 6epe1'aNt ceoepubtx mo- . pert. Hilipopmalutoilimii citoptutu 131-111P0, ;\12 8, 1960. 7 Tapareatm. M. H. 0 nuTattint 6e.uxit Ceoepa. «PhIGIIBB Bp0Mb1111:1C11110CTb», 61, 1962.

1. Arsen'ev V. A. Some data on the feeding of the beluga. Izvestiya TINRO (Proceedings of the Pacific Research Institute of Fisheries and Oceanography), vol. 10, 1937. 2. Geptner V. G. Information on the geographical distribution and biology of the beluga. Trudy Nil zoologii pri MGU (Transactions of the Zoological Research Institute at Moscow State University), vol. 4, No. 2, 1930. 3. Kleinenberg S. E., Yablokov A. V., Bel'kovich V. M. and Taràsevich M. N. The beluga. An attempt at a monogra- phic study of a species. Moscow, "Nauka°i 1964. 4. Klumov S. K. The beluga of the Soviet Union (the available supply and its exploitation). Trudy VNIRO (Transactions of the All-Union Research Institute of Marine Fisheries and Oceanography), vol. 12, 1939. 5. Kirpichnikov A. A. Observations on marine mammals in the south-eastern part of the Kara Sea. Byulleten' MOIP, otd. biologii (Bulletin of the Moscow Society of Natura- lists, Biological Section), No. 4, 1937. 104.

6. Tarasevich M. N. Regular patterns of approach of the beluga to the shores of the northern seas. Informatsionnyi sbornik VNIRO (Informational symposium of the All-Union Research Institute of Marine Fisheries and Oceanography), No. 8, 1960. 7. Tarasevich M. N. The feeding of the beluga in the North. "Rybnaya promyshlennost . " ("The Fishing Industry"), No. 61, 1962. 105

UDC 599.5 'V. I. Shevchenko

A CONTRIBUTION TO THE QUESTION OF THE ORIGIN OF "WHITE SCARS" 67

ON THE BODY OF WI.AIE S

In describing the external appearance of the large whales

all investigators have noted on the skin the numerous oval scars

of various shades, the so-called "white scars". In the literature there are descriptions of the colour,

dimensions, form and distribution of the white scars. The colour and number of these on the body of the whale serve as an indicator of the age. However up to the present time there has

been no unified opinion about their origin.

Andrews (1916) mistakenly accepted these scars as traces

6 of the activity of the ectoparasites Penella. In 1929 Mackintosh

and Wheeler put forward the proposal that the oval scars are the

consequence of healed ulcers, which in their turn were caused

by the activity of pathogenic mirroorganisms and protozoans.

Pike (1951, 1953) asserts that the white scars are the result of attacks by carnivorous marine lampreys. He found on the body of whales open clean wounds in the form of pits and their various stages of healing (ulcers). close to the coast of British.

Columbia. Nemoto (1955) described the wounds and scars on the body of whales from attacks by lampreys in the northern part of

the Pacific Ocean. However this author considers that these

are not identical with the so-called "white scars". In spite

of this, Slijper (1962) cites his work as a confirmation of the

point of view held by Pike. 106

The difficulty in resolving the question of the origin of the white scars consists of the fact that these scars arise in whales in the tropical part of the oceans, where there is no great whaling industry. Working on board the AKF* "Slava" and "Sovetskaya Ukraina" during the seasons of 1961 - 1968, we studied the characteristic features of the structure and disposition of white scars on the body of various species of whales. Sometimes, especially during the initial period of the whaling, we encountered ulcers in the last stages of healing (Figure 1).

Pue. 1. 08a.unbie inpambi u 513BoxiKa na 3amc1trLneunn Ha Te.le ceibasia

Figure 1. Oval white scars and ulcer in the last stage of healing on the body of a sei whale.

Thanks to the fact that in recent years the AKF "Sovet- skaya Ukraina" has commenced conducting whaling operations for sperm whales while still in passage in the tropic and subtropic

• * Translator's note. AKF Antarkticheskaya kitoboinaya flotiliya - Antarctic whaling flotilla. 1 07 parts of the Indian and Atlantic Oceans, we were able also to study fresh wounds and their gradual transition into ulcers. In examining the surfaces of the bodies of whales, alongside the white scars there were evident diverse scars from accidental wounds and the activity of parasites. Therefore we consider it necessary to give a precise description of the white sCars. On different whales the scars have certain peculiarities, 68 but there exist typical, characteristic features, which permit one to combine them under one common name, the "white scars".

, Pue. 2. Onaabnme n cepnonnunme mpambi na xnocTonom eTeCine ceibana Figure 2. Oval and falciform scars on the caudal peduncle of a sei whale.

The most common form of the white scar is an oval, with a long axis of from 4.5 to 9 cm, and a short axis of from 4 to 4.5 cm. As is evident from these figures, its dimensions vary from a strongly elongated to an almost circular form (Figures 69 3a, v). In some cases there are found ovals of irregular form, 108

g a e

•

a B r e a v g d e —nonepmocTlible Pile. 3. Pa3.1Itt1liasi rp opta Gum:: wpamou: I — yqacTog. xonTypbr. 11— npoRomblibift pa3pe3 gem uipam (I BII,L1,0113MCI1C11110r0 Diiii- Heumeuennoro .Dniutepinea; 2 — ytiacToK calla; 4 — RepNinca; 3— eihribuo icomaareim3upoBanubiri riae-rot( caw nopma;ibtioro crpoenita)

Figure 3. The varying form of white scarst 1 - surface contours; 11 7 longitudinal section through the scar (1 - portion of unchanged epidermis; 2 - portion of modified epidermis; 3 - strongly collagenized portion of fat; 4 - fat of normal structure).

in which the separate parts are as it were displaced relative to one another (Figure 3, b). Another form of the white scars is the falciform sear (Figure 2). The radius of the curve varies very little, from 1.5 to 2 cm, but the size of the open portion varies considerably (Figure 3, g, d, e). Generally the scar is distinguishable from the surrounding skin by the hue of the epidermis. On a dark background it is light-coloured, from a pure white to almost black, while on the white sections it may also be darker than the background due to a grey radiance. This radiance is not a specific characteristic of the white scars, it is formed after the scarring of any injury to the skin because of the interchange of pigmented and unpigmented portions of the epidermis. In the first year 109 the scars are generally pure white on any background, only sometimes does there immediately appear a dark medial strip. Then there appears the grey radiance, which with the passage of time loses its definition, acquires a similar tone and sometimes blends with the surrounding background. In the falciform white scars the epidermis is modified only along the edge, in the center it has the normal structure and coloration. A characteristic feature of the white scars is the presence under the layer of epidermis of a modified portion of the fat, in which there is a marked increasein the number of structural elements* collagen and elastic fibres. Due to this the border of the portion is clearly evident even in unstained section. Under the oval and round scars the modified layer has the form of a half-egg, with a maximal depth of 2.5 - 3 cm, while the surface dimensions are slightly greater than the visible outlines of the scar. In the longitudinal section of the falciform scars, under the epidermis of normal structure and a layer of fat there is evident a modified strip of fat, which abuts at one end on the modified epidermis and et the other end terminates in the layer of fat at the level of the ends of the sickle (Figure 2). We have attempted to establish certain regularities in the disposition of scars of various form on the body in different species of whales. 110

The greatest number of white scars was found in the

blue whales and sei whales. On the tail portion in these there

is formed a marbled pattern. There are relatively few of the

scars on the small whales of the Southern hemispherei the

bottlenose whales, killer whales and small rorquals. According

to the literature data, these scars are absent in right whales. The scars are present on all parts of the body, we have found them on the abdomén, jaws, blowhole and flippers. They

are most frequently localized on the caudal peduncle and sides

of the body. On the lower*side of the body there are somewhat more of them than on the upper side.

Most authors have noted that the white scars are elonga-

ted along the body axis. This is especially noticeable with

the elongated scars. The angle of inclination to the body axis r varies from 0 to 10-150 . Occasionally there are also found ovals

at an angle of 4-5- 60°. Al]. of the falciform scars are directed with the concave

part forward, towards the head or with a slight deviation to

the side. In blue, fin and sei whales the degree of elongation of

the scars (the ratio of the lengths of the long to the short axis) is considerable, averaging 1.74. on the sidemof the body. In the humpback whale and the sperm whale this index for the

same part of the body is smaller, 1.63 and 1.47 respectively.

In the latter species the falciform scars are found considerably

more frequently, especially in the sperm whale. On the sides of the body there are generally found

strongly elongated ovals. The closer to the caudal flukes, the smaller is the degree of elongation of the scars and the more i11

they approximate to a circle. Thus, for example, in 20 sei

whales, 15.0 to 15.5 m in length, the average degree of elonga-

tion of the scars (only the fresh scars were measured) in front

of the dorsal fin was 1.80, in the region of the dorsal fin

this was 1.72, on the caudal peduncle - 1,59 and close to the

tail flukes - 1.24. The frequency of occurrence of the falciform scars is greatest on the caudal peduncle close to the tail flukes. It

decreases towards the head.

In.studying the sperm whales that were caught in the

tropical zone of the ocean we ascertained that the ulcers, which

produce white scars when they become cicatrized, arise exclusive-

ly on the sites of pit-like or fâlciform wounds.. Consequently, s the ulcers are a.secondary phenomenon and not the cause of the white scars, as was considered by Mackintosh and Wheeler (1929),

and their microflora, evidently, is not pathogenic but the usual

microflora, characteristic of healing wounds. Thus, the question of the origin of the white scars is

reduced to a search for the causes of the formation of the cym-

biform and pit-like type of wounds.

During the cruLses of the AKF "Slava" in the 1963 - 1965

seasons and of the "Sovetskaya Ukraina" in 1966 - 1967, when

the flotillas, that were conducting whaling operations, were

crossing the Indian Ocean from the latitude of the Gulf of Aden

and the Island of Ceylon to 4.00 lat. S., we observed that fresh

wounds on the sperm whales appeared at latitude 19-20° S., both

close to the Island of Madagascar as well as in the open ocean

at the 70° meridian. In November in the warm zone, where mainly 112

Pile. 4. Tlynxonnaman pana (.1oRomKa) na Teme Rama.noTa co CAC- )1,31%111 3y6on na. 3a,u,ilert Npomxe

Figure 4. Pit-like wound (cymbiform) on the body of a sperm whale with tooth marks on the posterior edge.

females with young are found to occur, the sperm whales were caught very sporadically and therefore it was not possible to determine a distinct border to the region. It is interesting to note that in November the sperm whales in the region of the Gulf of Aden and the Island of Ceylon had no fresh wounds of the cymbiform and falciform type, and ulcers were also absent. These were also absent on three Bryde's whales from the Arabian Sea, although white scars were present on the bodies of these rorquals. The pit-like wound resembles in its form the impression which is left by a spoon on the surface of butter (Figure 4). If, however, only the upper layer is undercut with the spoon and then this spoon is removed, the trace that is left resembles the falciform wounds (Figure 5). Un the epidermis around the wounds there was not noted any damage. 1 13

Pitc. 5. Ceplioniumian patta co cae,amil fiT01)11411b1X ita.aRycon

Figure 5. Falciform wound with traces of secondary superficial bites.

The epidermis on the posterior edge of the fresh wound is always smoothed out towards the pit, while the anterior edge always has lacerated uneven margins. In some cases on the epidermis at the posterior edge there are distinctly evident denticles (Figure 10. From these there run down into the bottom parallel strips to approximately one third of the length. Such strips are evident even when the posterior edge is even. In the falciform wounds the posterior edge and bottom 72 have the same structural characteristics as in the pit-like wounds. On the epidermis in front of the wound there are generally no additional injuries. However in the case when additional injuries are present, there are present abrasions anteriorly (Figures 5 and 3,g*). The above enumerated characteristics of the structure of the wounds and white scars, and the regular pattern of their

* Translator's note, sic. probably 3, d. 114,

disposition on the body of the whale are difficult and at times even impossible to explain by attacks of carnivorous lampreys. The structure of their mouthparts is such that they cannot make either falciform wounds or wounds of oiralfform, especially of the elongated form of pits. The wounds produced by lampreys (Nemoto, 1955) are completely dissimilar in both form and dimensions from the cymbiform wounds, on the sites of which there subsequently appear the white scars. Analysing all of the material which was available to us, we arrived at the conclusion that the above-described wounds are the result of the bite of some one species or of some closelely related different species of sharks. From this point of view it is easy to explain all of the characteristics of the structure and disposition of the wounds and white scars, and also the common origin of the scars of various form. The fish attacks the whale from behind, catching up with it at high speed, and with its open lower jaw it undercuts a layer of epidermis and fat approximately to 1.5 - 2 cm, and the by the force of inertia and, apparently, with a jerk there occurs the tearing out of the piece, which is indicated by the tearing of the wound in its anterior part. The presence or absence of tooth marks in the form of denticles on the epidermis at the posterior edge apparently depends on the angle at which the jaw was jutted out and on the thickness of the epidermis. It should be expected that in the baleen whales these will be much less evident. The complex configuration of the cymbiform wound is formed in the case when the shark, having undercut the fat, 115

- makes a slight turn. The possibility of one wound being super- imposed on another also cannot be excluded. The falciform wounds are obtained when a shark, having undercut the fat to a certain depth, was unable to tear out the piece. Subsequently this grows back together. At the site of the concrescence is formed a colagenized strip of hypodermis and depigmented epidermis in the form of a sickle. The shark, having lost its speed, cannot bite off the undercutpiece of fat. In most cases it does not even attempt to do this. In Figure 5 is shown a falciform wound with marks of secondary superficial bites by the lower jaw. On the anterior edge of the wound are evident the tooth marks of tlie upper jaw, which generally does not participate in the act of tearing out the piece of fat. The irregularity of the pattern of distribution on the body of the whale of the marks of various form may be explained by the non-uniform consistency of the fat in the different parts. Along the sides this is softer, in it there are fewer collagen fibres, and the shark undercuts a larger segment of of the fat, and so strongly elongated ovals are obtained. The closer to the tail, the harder the fat, and consequently, the less undercut are the pieces, so .that the degree of elongation of the oval wounds is decreased and they approximate to a circle. It occurs more frequently that the shark is unable to tear off the undercut piece and therefore falciform wounds are obtained. There are more of these on the tail stock close to the flukes and on the flukes themselves, i.e. where the fat is the hardest. 116

The different average degree of elongation of the white scars in the baleen whales and in the sperm whale is also explained by the hardness of the fat. la the sperm whale, in which the upper layer of fat contains a very large number of collagen fibres, the falciform scars are also encountered considerably more frequently. The elongation of the oval scars along the body axis and the disposition of the falciform scars with thèir concavi- ty towards the head are explained by the fact that the shark attacks from behind, from the most convenient position for it, , since in connection with the ventral position of the mouth it is necessary for it to approach the moving whale along a tan- gent to its surface. By this also is explained the relatively large number of marks on the tail stock, since this is first encountered by the shark during its attack. Furthermore the tail stock is in constant motion which makes it clearly noticeable to the shark. In favour of our point of view is the fact that the white scars are situated both on the upper half of the body as well as on the lower half, and moreover there are somewhat more of these scars on the lower half. As is known, the shark is capable of turning over onto its side or back when attacking its prey. The conjectured species (possibly more than one) of shark, on the basis of the characteristics of the structure of the wounds and the regions of their appearance, must be an inhabitant of the pelagial in the tropical zone of the oceans o (10 - 25 lat. S.). 117

If one accepts the size of the short axis of the oval o of the wound as the width of the lower jaw at its base, this will be equal to 3 - 4 cm. From this, the size of the wound* will be approximately 50 - 100 cm. There must be functioning only one row of synchronous triangular teeth, which fol:sm an uninterrupted cutting edge. In Figure 4 it can be seen that the edgeeof,the teeth are set obliquely outwards. The two middle teeth are symmetrical. Their number in half of the lower jaw is approximately 14 - 18. These requirements are met by certain small species of the families** Shvrna (order Lamniformes), Etmopterus and Osistius (order Squaliformes). To establish the species (one or more) of shark precisely it is necessary to carry out dissections of the stomachs of the small pelagic sharks in the zone of latitude 15 - 25 ° , especially during the winter period, when the whales gather here.

REFERENCES

JIHTEPATYPA

Andrews R. C. Monografs of the Pacifis Cetacea, II. The.s,ci whale (Ba- laenoptera borealis Lesson). Meru. Ara. Mus. Nat. Hist, n, s, 1(6), 1916' ' Mackintosh and Ineeler J. F. Southern blue arid fin whales. Discovery Re- ports, 1, 1929. Nenzoto T. White scars on Whales—Lamprey marks. Scient. Repts. Whales Res. Inst., no 10, 1955. Pike G. C. Lamprey marks on Whales. Journal Fisheries Research Board 431 Canada 8, 1951, Pike G. C. Progress Reports of Pacific Stations, no 97, 1953. Sliiper S. J. Whales. London. 1962.

Translator's notes. * sic. Obviously should be "shark". ** sic. Presumably - "genera". 118

UDC 599.51 M. V. Ivashin

CASES OF MULTIPLE - PREGNANCIES AND FOETAL MONSTERS 75 IN THE BALEEN WHALES

Multiple pregnancies in all of the baleen whales are encountered relatively rarely (Table 1). Thus, according to the data from the international whaling statistics, in the main (until recently) commercial species of baleen whale, the fin whale, there were noted 910 cases of multiple pregnancy (0.938%) in 97041 pregnant females in Antarctic waters during the 1933/34 - 1967/68 seasons, and among these the most frequently noted were double pregnancies (0.895%). During almost every whaling season there were found pregnant females with three foetuses. larger numbers of foetuses were noted considerably more rarely. According to a report by A. Jonsgard (1953),on the 25th of February 1953 on the whale factory ship "Abraham Larsen" in a female fin whale, 21.9 m in length, there were found six foetuses in the uterus: two males, 353 and 238 cm in length, and four females, 315, 289, 282 and 221 cm in length. On two occasions there were found five embryos in sei 76 whales by the Antarctic whaling flotilla "Sovetskaya Ukraina". On the first occasion this number was found in a female 16.0 m in length, which was killed near the Balleny Islands. There were two males, 88 and 230 cm in length, and three females, 193, 213 and 220 cm long.*

* This footnote is given on the next page of this translation.

119

Table 1. • The frequency of occurrence of multiple pregnancies in Antarctic whales during the 1932/33 - 1967/68 , seasons.

Ta6jiiiva 1

IlarroTa nmetmemOCTII NIHOE0i1J10,11,1irt y anTapirrnvecKnx KIITOB . n ce3onps 1832/33-1967/68 rr.

A. B•HOMPICCIDO autIplictinn Species 1Z0nit4ecr00 1311 0bt 1Z11700 6eperaenublX Bcepie of whale cam« 2 3 4 5 • 6 Total clina: Blue no eLLIT. 23409 188 11 199 jel' 0,803 0,047 0,850 timimaa: Fin no err. 97578 875 s 31 5 2 3 916 % 0,897 0,032 0,006 0,002 0,003 0,940 rop6all: Hum back no en. 4968 27 1 28 0,543 0,020 0,563 Cell= Sei no JUT. 19496 319 12 1 1 333 1,636 0,062 0,005 0,005 1,708

• A. - Numberof pregnant females B. - Number of embryos

Such a marked difference between the twins was due to the fact that in the first of these there was noted embryonic

death, which had occurred 2.5 - 3 months before the capture of the whale.

The second similar case occurred in March of 1969 in this same western portion of the Pacific sector of the Antarc-

tic. During the dressing of a female sei whale, 16.7 m in length, there were found five embryos, of which, as in the

* (from previous page) The mention which was made (Zoological Journal, vol. 40, No. 2, p. 311, 1966) of a sixth embryo was not confirmed either by its presence (the reference to its falling out while the whale was being dragged up onto the deck was quite unfounded) or by the results of examination of the ovaries, and therefore cannot be accepted. 120 first case, there were two males (168 and 339 cm in length) and three females (203, 304• and 334• cm in length). Both males were normally developed, although there was present a very

considerable difference in their dimensions. Judging by the

freshness of five traces of corpora lutea of pregnancy out of the eight present, it may be assumed that the preceding pregnancy was also possibly multiple, with five foetuses #.

In a female blue whale, caught off the coast of the

Island of South Georgia in 1925, there were found 7 embryoss

three males, of length 135, 131 and 127 cm, and four females

- 132, 127, 107 and. 97 cm in length.

It is customary to distinguish two types of twins:

identical and non-identical. Those twins are called identical,.

which develop from one egg cell (zygote). Shortly after being

fertilized by a spermatozoon such an egg cell may divide in

half. In this case there will be two twins. Sometimes after the first division there occurs a new division of each part

of the egg cell into halves (always a multiple of two). In

this manner the appearance of four and more foetuses becomes

possible. Subsequently, however, there cannot be excluded the possibility of death of one or more parts of the developing

zygote, which provides conditions for the appearance of an

uneven number of embryos (3, j, 7). All of the embryos are

surrounded by a sinle chorion, and normal development of these

proceeds.

The author expresses his thanks to V. L. Yukhov, the senior scientific officer on the AKF "Sovetskaya Ukraina", for the information on this case. 121

However, if the division of the zygote is accomplished a few days after fertilization during the process of the commencing development, the appearance of grown-together (siamese) twins is noted. In those cases when there are simultaneously fertilized two (or more) egg cells (in which cases there is not excluded the possibility of the division of one of these into halves etc.) there appear non-identical twins, surrounded by independent chorions (if there did not occur a division of one of the 77 egg cells into two or more). From obstetrical practice it is known that approximately once in every 85 - 90 cases of normal birth there occur twins. Triplets are noted once for every 85 - 90 cases of birth of twins. The occurence of quadruplets hàs also been recorded once for every 85 - 90 cases of birth of triplets. Quintuplets are encountered once for every 85 - 90 cases of birth of quadruplets or, on average, once in every 52 - 55 million births. A somewhat different relationship is found in the fin whales. Thus, for every 112 cases of normal pregnancy there was noted one case of pregnancy with three* foetuses. Cases of multiple pregnancy (with three or more embryos) in whales are encountered frequently. On the one hand, this may be a confirmation of the known fact of the once existing multiple gravidity in whales in the Past and, on the other hand, this may be conditioned by the relatively small volume of material studied, when the significance of individual cases is greatly increased.

* Translator's note. sic. Obviously this should be "two" here. 122

The largest number of females with twins was noted in the sel whales - 1.636%; in certain years this was as high as 3.0 - 3.z and even 4.2% (the 1954/55 season) of the total number of pregnant females. Triplets in this species were encountered more frequently than in other species of whales (0.062A). Cases of multiple pregnancies were encountered most rarely in the humpback whales (0.563%): less, by a factor of 1.5 - 3, than in the blue whales and sei whales. Twins in the humpback whales were also rare (0.543%). In the 1960/61 season in the area of the feeding migration of the New Zealand stock there was caught a female humpback whale, 13.7 m in length, which was then brought to the whale factory ship "Sovetskaya Ukrainan. During an examination of the left horn of the uterus there were foUnd three embryos: a female 51.5 cm in length (weight 2910 gin), a female 50.5 cm in length (2560 gin) and a male 45 cm in length (weight 1810 gin). foetus had a separate chorion. The embryos were normal- Every ly developed. In the first of these we counted 10 folds on the ventral gular side, in the second there were 8, the third did not have these yet. On examination of the right horn of the uterus there was no embryo, though there were found remaining torn chorionic membranes. However, in spite of a thorough search, it was not possible, unfortunately, to find the foetus.* Apparently, in this female there were not three but at least four embryos.

* It should be noted thatl at this time, loading of the whale raw material was being carried out on decle and the embryo, which had been outside the uterus, apparently fell into the fat boiler. The female was examined by senior scientific officer Yu. P. Golubovskii. 1 23

The ovaries of this female were taken for examination (it was found to be impossible to remove the ear plugs which is necessary for determining the age). The left ovary, 25 X 9 cm in size, weighed 1020 gm. On it there were situated three functioning corpora lutea of pregnancy of dimensions 80 X 70, 75 x 50 and 80 X 75 mm, with corresponding weights of 220, 150 and 240 gin. They had a con- striction at the base and were located on the anterior part of the ovary. Two functioning corpora lutea of pregnancys were touching one another, while the third was located somewhat to one side. The right ovary, 27 X 8 cm in size, weighed 840 gm. In the anterior part there was located a functioning corpus luteum of pregnancy, 95 x 85 mm in size and weighing 260 gin. On the middle of the ovary there was located a trace of a corpus luteum of pregnancy, a second - closer to the end of the anterior part of the ovary. In their dimensions and amount of connective and lutein tissue, these traces of the corpora lutea of pregnancy were very similar to one another and their origin should be referred to one reproductive season. It is therefore possible that in the preceding season there was a multiple pregnancy in the female. In multiple pregnancies the embryos are most frequently differentiated from one another by the length of the body and, as a.rule, are quite normally developed. Among the twins there are most frequently encountered dizygotic twins, while monozygotic twins are extremely rare, although according to the calculation of S. Kimura (1957) there should be 27.6% of 1214• • these in the females of the fin whale. Most probably such twins develop from two egg cells which have matured in one follicle. There is even possible the development of three egg cells in one follicle, which was found by R. Chittlborough (1954) in a female of the humpback whale. According to the data of P. Petskii (1955) uniovular embryos in cattle may be found only in the form of incompletely separated twinned monsters. A. Kawamura (1969) was the first to study siamese twins in cetaceans. In December of 1967, in the Indian Ocean sector of the Antarctic, there was caught a female sei whale 15.2 m long. During dressing, there were found in it two male embryos, 137 and 144 cm in length. On the ovaries of the female there were only three traces of corpora lutea and one functioning corpus luteum of pregnancy. Consequently, the embryos had developed from one egg cell, which had divided into two approximately a week after fertilization. The foetuses were grown together by the ventral side from the thorax to the umbilicus and had a single umbilical cord for bbth of the twins. A case of teratic development, which was previously described by us (Ivashin, 1960), may be supplemented by the following. During the 1959/60 season on the whale factory ship "Sovetskaya Ukraina" we examined a male embryo, 111 cm in length, which was removed from the right horn of the uterus of a humpback female 'body length 13.3 m). In this foetus le) there was found a teratic development of the upper part of the head (Figure 1). The somewhat elongated and broadened left slit of the blowhole was located in the normal position. 125

•

■ ■ ■■■ ■ ■.,....1...ii).,..11;:à, I4.4 ,..• C tie....i..... 41:.,..i".....,1 M1 44,,,, ,, .i14 .4,.•;.: 4$4.::.e.i,j`ewn

Pue. 1. -3- m6piroli-caMeR 4iuuna.ia Aniniori 111 C.11. (POTO aaropa

Figure 1. Male embryo of fin whale*, 111 cm in length. Photograph by author.

The right slit could not be detected. In its place, somewhat 79 anteriorlàr there was located a complete opening. The left intermaxillary and maxillary bones were developed normally at the base of the head; at about the middle of their length they were bent to the right and narrowed towards the end, having a r-like form. The right intermaxillary and maxillary bones were a little thinner and, already from the base of the head, they were markedly turned to one side in such a manner that their end, which was almost at the mid-line, was bent round still more to the left and 'backwards, being situated above the ends of the corresponding bones of the left side. On the upper jaw there were normally developed hairs seated in brightly coloured capsules. The right intermaxillary bone terminated at the through opening, while the left was deflected to the right at an angle of almost 900 behind the left slit of the blowhole (Figure 2).

* Translator's note. sic. should be "humpback whale". 126

Pue. 2. LIacrb roaorm m6puoila qumna.ia. (2,:utua Teaa 111 cif) . lioro atiropa

Figure 2. Part of the head of an embryo of a fin whale* (body length 111cm). Author's photograph.

• The vomer is normally developed approximately to the level of the blowhole slit, then the tissues which cover it on one aide (below from the left) form the through opening, while on the right there is situated the blindly ending opening of the blowhole. In front of the blow hole is a dark formation, 30 X 40 mm in size. On the right ovary of this female there was found one functioning corpus luteum of pregnancy and one trace of a corpus luteum of pregnancy, as well as 10 traces of corpora lutea of ovulation; on the left ovary - 2 traces of pregnancy and 7 traces of ovulation. In the 1960/61 season in a primigravid female fin whale, 19.7 m in length, in the right horn of the uterus there was found a female embryo 255 cm long. This was normally developed, with the exception of the upper jaw (Figure 3). At a distance of 12 cm from the middle of the blowhole the upper jaw turned

* Translator's note. sic. Should be "humpback whale". 127

I'Frc. 3. I'o.lona.qmôpuofia cj>Minaaa-caatua (,q.qIMa Tua 255 cm). (POro aaroRa

Figure 3. Head of embryo of male* finwhale (body length 255 cm). Author's photograph.

sarply (at an angle of 1000) downward and entered the cavity of the mouth. The length of this part of the jaw was 27 cm.

The tip of the snout was weakly turned inwards, while the

Jacobson's organ, situated on the snout, was markedly convex. 80

In the normal position for this embryo, with the mouth closed, the end of the snout over the tongue (which in this place was of a lighter colour and slightly softer than the surrounding tissue) rested against the base of the mouth cavity and noticeably pushed this downwards. At a distance of 23 - 24• cm from the corner of the mouth the right and left parts of the lower jaws became narrower and were found to be bent inwards to a distance of u• - 5 cm. The ends of the jaws were normally joined by tne symphisis.

* Translator's noté. sic.-In.the text (third line of last paragraph on p. 126 of translation) this is given as a female. 128

Pa. 4. r0.70L8 3\f6}]i101I2 Coj)6aTOI'0 KI1T8 (amma Te:11 41 cm). (POTO [k87'Opa

Figure 4. Head of embryo of a Humpback whale (body length 4.1 cm). Author's photograph.

A similar case was described by W. Cockrill (1960) in 81

the embryo of a blue whale and by M. M. Sleptsov (1955 )in the

embryo of -a fin whale 4.0 m in length.

In order to determine the age we examined the ear plug

of this female fin whale. In all we counted 11 layers, which

possibly corresponds to an age of five years for the female.

As is known, in all of the baleen whales the normally

developed lower jaws always extend beyond the end of the snout

(to a distance of 25 - 4-0 cm), thanks to which the upper jaw

freely enters the bed formed by the lower jaws. There have

been almost no mentions in the literature of exceptions to

this general rule.

We examined a male embryo, 4.1 cm in length, taken from

a female humpback whale 11.8 m long. In it the upper jaw was G found to be somewhat longer than the lower jaw (Figure 4.), in connection with which it cannot be normally situated in the 129 bed of the lower jaws. Apparently, this situation may have been retained in the grown animal had development continued. There was also noted a case of a considerable bend of the ends of the upper jaw ma male humpback whale (body length 11.0 m). As in the case described by us previously (Ivashin, 1958), this was a normally developed whale in other respects. The teratic development of the upper jaw prevented the normal , closing of the mouth cavity. In this humpback whale, however, the baleen plates at the place of the bend were distinguished by their increased dimensions as compared to a similar sector of the row of baleen in a normal whale. This circumstance is connected with the fact that the baleen plates had the possibility of growing until they encountered in their way the lo- 82 wer jaw (with the mouth cavity closed), when the wearing out of the tips of the plates commenced. In this way there was compensated the defect in the development of the upper jaw at the point of occurrence of the strong bend. During whaling operations for humpback whales there was caught a whale (male, length of body 13.3 m), in which the ends of the tail flukes formed a closed circle. Unfortunately, not having been warned in time a sailor succeeded in cutting open the circle and we were able to see only a part of this interesting formation (Figure 5). In other respects this humpback was found to be normally developed and fully nourished. The sailors who had hunted him stated that his behaviour and speed of movement were in no way different from the other whales which were together with him in this group. 130

Pue. b. XTIOCTOBble nonacrit camna rop6a -roro Kwra (Aanna Tena 13,3 Al) nocae nx o6pa6o -rmi na NuToüoiinoNt mute

(POTO OOTOO

Figure 5. Tail flukes of male humpback whale (body length 13.3 m) after being treated on a whaling ship. Author's photograph.

The main organ responsible for the forward movement of the whale is the tail stock. Together with the lobes situated at its end, the tail stock performs up and down oscil- lations. Depending on the inclination of the tail flukes to the longitudinal axis of the body of the whale, there occur changes in the direction of movement (submerging or surfacing). In the whale under consideration the modified tail flukes did not interfere with the regulation of submersion and with the accomplishment of movement over :thousands of miles from the wintering places in the warm waters to the region of the feeding migration in the waters of the Antarctic. Previously there were known cases when whales without tail flukes had accomplished long migrations (R. Gilmore, 1959). There was also recorded a case of the death of embryos, found by us in a female humpback whale, 13.8 m in length. 131

Piic. G. .11,13a Nt6p Holt a rop6wroro miTa (J muli' Tula 55 it 54 cm), y KOTOpbIX ontetiena 3m6plionam,Ha7i cmepTilocrb Ooro aaropa Figure 6. Two embryos of the humpback whale (body length 55 and 54 cm) in which embryonic death was noted. Author's.photograph.

These were a male, 55 cm in length and weighing 4000 gm, and 83 a female, 54 cm in length and weighing 3850 gin (Figure 6). According to our observations, embryos of such a length generally have a weight of from 1300 to 3000 gm. They were situated in different horns of the uterus. The body tissues of the embryos were found to be soft and flaccid, the abdomi- nal part had a pronounced sag and the organs located within this could be easily displaced by weak pressure of the hand. 132

The functioning corpora lutea of pregnancy in this female were normally developed and very distinct. One ovary with a functioning corpus luteum of pregnancy, weighing 1450 gin, had no other formations. On the second ovary there were found: a functioning corpus luteum of pregnancy weighing 890 gm, three traces of corpora lutea of pregnancy and two traces of ovulation. According to the data of T. Ishihara (1962), death of 84 foetuses during the intra-uterine period in whales is rarely encountered. Thus, out of 9400 examined embryos of fin whales only in 17 (0.1410) was embryonic death found. Death was noted more frequently in the case of multiple pregnancy, which is connected with the limitation in the supply of nutritive sub- stances, necessary for the development of the embryos. up to the present time the causes of the appearance of developmental anomalies of the organism and intra-uterine mortality remain unclear. S. Cohlan (1963) relates a large part of the detected cases of developmental anomaly to the influence of numerous, very complex and but little studied interrelationships between external and genetic factors. Cases of developmental anomaly of foetuses, of embryonic mortality and of the occurrence of viable foetuses with certain teratic parts of the body or organs are known for all terrestrial mammals, and also for man. Marine mammals (in this case - cetaceans) are no exception; the examples described are indicative of the rare cases of occurrence of various deviations during the process of development in whales. 133

REFERENCES

J1FITrPATYPA

I !/oaruurt Al. B. Cayt(an artoatMuït y:icnnoTUhIX. «1lpnpola», JM2 4, 1958. 2 l;laaurmt M. B. O nluoron:toAUU, vpo;uTnaX pasBUTUSI it wtGpnonaabnoii entepTnocTtl y xnTOB. «3oo:lorn1tecxnt( >;

("Nature"), No. 4, 1958-

2. Ivashin M. V. Multiple pregnancies, developmental monsters

and embryonic mortality in whales. "Zoologicheskii

zhurnal" (Zoological Journal), vol. 39, No. 5, 1960•

3. Petskii P. •Embryonic parabioses and multiple pregnancies

in agricultural animals. Trudy instituta morfologii

zhivotnykh AN SSSR (Transactions of the Institute of

Animal Morphology of the USSR Academy of Sciences),

issue 14, 1955-

4. Sleptsov M. M. The biology and commercial exploitation of whales in the far-eastern seas. nrioscow, Publ. Pishche-

promizdat (Food Industry Publishers), 1955- 134

SECTION II.

THE EC °LOGY, DISTRIBUTION AND COMMERCIAL EXPLOITATION OF SEALS FUR SEALS AND SEA OTTERS 135

UDC 599.711.5.3 G. A. Fedoseev

THE DISTRIBUTION AND NUMBERS OF SEALS ON WHELPING 87 AND MOULTING PATCHES IN THE SEA OF OKHOTSK

The literature data (Freiman, 1935; Lun", 1935; Ni- kulin, 1937; Dorofeev, 1940; Pikharev, 1940; Naumov, 1941) on the distribution of seals on the whelping and moulting patches in the Sea of Okhotsk are scanty and were obtained mainly as a result of observations carried out from shore or from commercial vessels in May - June, i.e. during 'the moulting period. An exception to this are the studies of A. Tikho- mirov (1961, 1966), who started extensive reconnaissance flights to detect commercial concentrations of seals on the ice in the Sea of Okhotsk. However, even his data by no means completely characterize the distribution of the seals, while information as to their numbers is lacking from his studies. In 1968 - 1.969 we studied the distribution and numbers of seals in the Sea of Okhotsk on the whelping and moulting patches. This work was conducted from an I1,-14 aeroplane. The observations were made from an altitude of 100 m at an angle of 45 ° , and therefore the width of the registered strip was equal to the flying altitude, i.e. 100 m. The animals that were lying on the ice were clearly visible at a distance of 500 m and more; however, with such a scanning width, the identification of species was difficult and errors arose on account of the omission of individual animals, especially of whitecoats. Adult animals, frightened by the sound of the aeroplane's 136 engines, generally escaped into the water, while the whitecoats remained on the ice, trying to conceal themselves or to remain motionless. The frightening of the seals did not interfere with the carrying out of the observations; on the contrary, it was easier to notice the movinganimals than those which were not moving. In the observation journal, using symbols that had previously been established, there were noted for every five minute period of flight the numbers of animals encountered, the various ecological situations (the number of holes, whether a whitecoat was lying with a female or by itself, where it was lying - beside a hummoch, crack or hole etc.). Besides this, the ice conditions were noted on the map by a hydrologist ob- server. In this manner, for any particular moment of the flightdata were available on the number and species composition of the seals and on the character of the ice on which the animals were found. Taking into consideration the speed of the flight and the width of the area scanned, we calculated the numbers of seals per square kilometer and their total numbers on the studied ice mass. The total distance of the air transects comprised 85 thousand km (340 flying hours), which included 27 thousand km in 1968 and 58 thousand km in 1969. In addition to the author, A. V. Evzerov and L. D. Kovaleva took part in this study, while V. N. Gol'tsev and G. M. Kosygin also participated in individual flights. 137

DISTRIBUTION OF THE SEALS

The distribution of the seals in the spring period, as was indicated by S. V. Dorofeev (1935) and S. Yu. Freiman (1935), is determined by the presence of places suitable for reproduction. The periods of whelping in the Okhotsk seals, as a rule, coincide, but the conditions for reproduction are specific to each species. In connection with this the distribution of the Okhotsk seals is given by us according to species. The ringed seal • It is known that in the Antarctic*seas during the winter period the ringed seal builds dens in the snow (Naumov, 1933; Chapskii, 1940; Fedo- seev, 1965, et al.). In the Sea of Okhotsk this species whelps on the ice, without building dens, which is conditioned by the milder climate of the Sea of Okhotsk, as compared with the Arctic seas (Fedoseev, 1965). Some animals, however, here also build dens in snowdrifts, that are formed around hummocks, which, as a rule, are opened up in the second half of April. The females live near the holes during the course of the entire period of feeding the cubs and, apparently for some time before these are born. Mating occurs soon after whelping and the males apparently live together with the females. In winter and spring (March, April) the seals live a settled way of life near the holes made by them. The extended residence of the seals on one and the saine pieces of ice, connected with whelping, compels them to select for their whelping fields of firm white ice. In the Sea of Okhotsk such ice is found primarily in its north-western part, in Shelikhova

* Translator's note. sic. Presumably printer's error for "Arctic". :13,8

Bay and off the eastern coast of Sakhalin. In these regions are concentrated the whelping patches of the ringed seal. There is no doubt that the distribution of the seals is also influenced by the presence of available food in the various regions, however the ice conditions are, in all probability, the main factor. In any case, the change in the distribution of the whelping patches in different years is dependent on the processes of ice formation. For example, in April of 1968 fields of white ice were found in almost the whole area of Shelikhova Bay and in the inshore regions of the north- western part of the Sea of Okhotsk. And here also were concentrated the main whelping patches of the ringed seal. In April of 1969 fields of white ice were found only in the central and north-western parts of Shelikhova Bay (along the coast from Cape Viliginskiy to Iret" and in Yamskaya Bay). In the rest of this area there was a predominance of grey ice with an admixture of grey-white ice. As a result of the re- duction in the fields of white ice the numbers of ringed seals on the whelping patches in Shelikhova Bay were one quarter those found in 1968. In the north-western part of the Sea of Okhotsk, from the lisyanskogo peninsula and almost up to the Shantarskiye islands, within the zone of 50 - 100 miles from the coast in April of 1969 there also predominated grey and rind ice, while in 1968 fields of white ice were predominant here. In accordance with this, there was a marked change in the distribution of the ringed seal on the whelping patches (Figure 1). In 1968 the whelping patches were primarily confined to the 50 - 100 mile coastal zone, to the south of 57° lat. N. there were few ringed seals, while in the region of 139

Pmc, 1. Cxenta pacnpeAe.aenn$ axnftt n mennyiH nepnoR

Figure 1. Schematic map of the distribution of.the ringed seal during the whelping period.

A. - Zegend: - migrations_ to moulting areas

Tony Island and to the south, to the Island of Sakhalin, it 9o

was not found. In 1969, in contrast, the whelping patches of

the ringed seal were disposed further out to sea, to a dis-

tance of 200 miles and more from the coast, extending to the

south almost to the Shantarskiye Islands and to the Sakhalin-

skiy Zaliv. It is.noteworthy that in 1969 the numbers of the 140 ringed seal off the Island of Sakhalin increased sharply, which was conditioned by the general displacement to the south of the whelping range, in connection with the change in the ice conditions noted above. In this region the ringed seal was encountered along the whole of the eastern shoreline of Sakhalin and in Terpeniya Bay. To the south of 45 ° lat. N. we did not find any whelping patches, although in the opinion of foreign investigators the ringed seal is a permanent resi- dent off the coasts of the Island of Hokkaido and North Korea (Wilke, 1954; Nishiwaki and Nagasaki, 1960). According to our data, the main whelping patches of the ringed seal off Sakhalin are concentrated along the north eastern coast from Lun'skiy Bay to Cape Yelizavety. The density of the accumulations of the ringed seal on the whelping patches is not high and in different regions ranges, on average, from 0.2 to 3.2 animals per square kilometer. Thus, the whelping patches of the ringed seal in the Sea of Okhotsk are disposed in three regions; along the north- western coast from Tauyskaya Bay to Ayan; in Shelikhova Bay, and off the east coast of Sakhalin. In the last two regions, depending on the characteristics of the ice regime in different years, the approaches of the ringed seal to reproduction are not uniform. In May, when the intensive breakup of the ice begins, there occurs the formation of the moulting patches. At the same time some animals move towards the north-western shores - into the regions of Yeyrineyskaya Bay - Okhotsk, Khanyangda - Ayan, others move towards the Shantarskiye Islands and to the Sakhalinskiy Zaliv. Moulting patches are formed also in

Shelikhova Bay and off the north-eastern coast of Sakhalin.

The density of the accumulations of ringed seal in-

creases sharply. On one ice floe of 100 - 150 square meters there may be encountered 30 -4.0 and even more animals. In the middle of May the concentration of the ringed seal increases and in the field of view there may be seen several hundred animals si.multaneously, and sometimes even accumulations of thousands, especially in the region of Yeyrineyskaya

Bay, Ayan, the Sakhalinskiy Zaliv and the Shantarskiye Islands.

Similar concentrations of the ringed seal have been well described by G. A. Pikharev (194•0).

T h e b e a r d e d 's e a 1 . N. A. _Smirnov (1.927 ) noted that the bearded seal of the European North; like the ringed seal, makes a hole in the ice. In March of 1964•, during a voyage on the ice-breaker "Moskva" in the Sea of'Okhotsk we were able to observe bearded seals lying near holes (Fedo- seev, 1965). In April of 1969 in the northern part of the Sea of Okhotsk there were also encountered bearded seals which were lying with their pups close to holes (not infrequently in familiess male, female, whelp). However the bearded seal 91 makes its holes-not in white ice but in grey ice, 15 - 20 cm in thickness.

The area studied by us was evidently composed of light floe white ice of a density of 8-9 degrees. With the establishment of calm freezing weather here there were formed fields and floes of white, grey and rind ice. And with the freezing up of the polynia, cracks and leads, the bearded seals began 14•2 to make holes in the grey ice. The holes were made near the edges of white ice floes, on which lay the pups and adult animals. Close to the bearded seal families or to cubs that were lying by themselves there could be seen 2 - 3 holes arranged in a row and another 4 - 5 single holes were observed within a radius of 100 - 200 m. The distribution of the bearded seal is determined to a considerable degree by the depth, which was especially evident in the region of the island of Sakhalin, where the drop- off in depth is situated closer to the coast than is the case in the northern part of the Sea of Okhotsk. In the Sea of Okhotsk there can be distinguished two regions of whelping patches of the bearded seal, which corres- pond to the specific features of the biology of reproduction of this species: the eastern coastal region of Sakhalin, including the Zaliv Terepeniya, and the northern part of the Sea from Tauyskaya Bay to Shelikhova Bay inclusively (Figure 2). However in different years the distribution of the whelping patches of the bearded seal changes in relation to the distribution of the ice and the course of the process of ice formation. In 1968 in the northern part of the Sea of Okhotsk Shelikhova Bay was the main region of the whelping of the bearded seal. In 1969 there was considerably less ice here that was suitable for the reproduction of this seal and the whelping patches were displaced to the west, to the Tauyskaya Yamskaya region. However, in the off-shore zone off East Sakhalin and in the Zaliv Terepeniya we did not notice any 143

substantial changes in the distribution of the whelping patches

Ô of the bearded seal in different years. The density of the accumulations of bearded seals was not high and ranged, on average, from 0.2 to 0.8 individuals per one square kilometer. In May, with the beginning of the intensive breakup of the ice, the bearded seal remains in almost the same regions as in April. With the disappearance of the ice off Sakhalin the bearded seals, like the other seals, move into more northern regions, in some years moving as far as the Sakhalinskiy Zaliv (Tikhomirov, 1961). From the northern part of the Sea with the breakup of the ice the bearded seals sometimes move into its north-western coastal regions or remain in the Tauyskaya - Yamskaya region.

The ribbon seal. In contrast to the other species, this seal never makes holes even in thin ice. For this reason obviously it lives only in those regions where there are present polynia and patches of open water. The ribbon seals whelp exclusively on white, hummocky light floe ice of marine origin, interwoven with polynia and patches of open water. Ice of this type in 1968 - 1969 was situated in the region of 44P 30' - 57 0 lat. N. and 143° ° long. E., and also within 50 - 100 miles from the - 151 eastern coastline of Sakhalin and in the Zaliv Terpeniya. The distribution of the ribbon seal in the Sea of Okhotsk variese depending on the ice conditions. Thus, in 1968 a large part of the whelping patches was noted off Sa- khalin, while in 1969 these were found primarily in the region

114.4

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, i el ), 41 c a Marapart 2encic 4, i.,.1. ,.__, e ■.

....1 v„..g.iii. . ,• 1 '-.---.7..-.....-- Rfill

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—i;68 r 1 7---- — — / .96, 9 r: ,•"'" m LI 2,0 1:11( Ulf , tç-- - /fa _nuttcwcy I . ■ , 1. ___.---..--.,....._--,------1 5" 15te 135 °

Pue. 2. Cxema paenpeRe.ricalla oaxTaKa B tueamdi nepaoR

Figure 2. Schematic map of the distribution of the bearded seal during the whelping period.

A. - Legends migrations to moulting areas

of 550 30' - 57° lat. N. and 143 - 151 ° long. E. In 1956 E. A. Tikhomirov (1961) found whelping patches of the ribbon seal in the north-western parts of this Sea. The density of the accumulations of the ribbon seal on the whelping patches is not great, averaging 0.5 animals 1115

/3e 140- me Ise 160"

[/lecnog-tible acro3temeaug: 1960 r - 45' BaPegneintearÀuile PC(20/45( ce) - /968r •-• /965, r ell/ZPazei/c/ flUt big./ ,11 155°

Pic. 3. Cxente pacnpeRe.lettityt Kpbt.namat B ueniii,iù nepimA (anpe.lb)

Figure 3. Schematic map of the distribution of the ribbon seal during the whelping period (April). A. - Legend: B. - Conjectured regions migrations to moulting areas

per square kilometer. In May, when the moulting patches are formed, the ribbon seal actively migrates into those regions where the ice remains for the longest time (Figure 3). 1 4.6

Our observations do not confirm the opinions of E. A.

Tikhomirov (1961), concerning the passive migration of the ribbon seal, as also of other species of seals, on drifting 9y.

ice floes. On the contrary, both off Sakhalin as well as in

the north of the Sea of Okhotsk the ribbon seal often migrates

in a direction opposite to the drifting of the ice.

T h e h a r b o u r s e a 1 . According to the

data of E. A. Tikhomirov (1961), the whelping patches of the

harbour seal are formed in the following regions of the Sea

of Okhotsk: in the Terpeniya Zaliv, off the eastern coast

of Sakhalin, off the north-western coast of Kamchatka, in

Yamskaya and Tauyskaya Bays and in the region from the IConi

peninsula to the P'yagina peninsula.

According to our observations, the harbour seal, like

the bearded seal and ribbon seal, selects for its whelping

regions of light floe white ice, with polynia and patches of

open water, although in 1969 in the northern part of the Sea

whelping patches were situated on fields of white, grey and

rind ice. The animals lay in families around holes which had

been made in the young ice.

Some harbour seals, judging by the tracks on the ice

(snow), moved over a considerable distance in search of cracks

or open patches of water. In individual cases the distance

of such movements was as high as 10 kilometers and more.

Our data on the distribution of the whelping patches

of the harbour seal basically confirm the information given

by E. A. Tikhomirov (1961), although in 1968 and 1969 in the

northern part of the Sea of Okhotsk the whelping patches of 1 47

Pile. 4. Cxema pncripep,eaeillin nepuo,u, (anpeab)

Figure 4. Schematic map of the distribution of the harbour seal during the whelping period (APril). A. - Legands - migrations to moulting areas

the harbour seal were situated at a considerably larger distance from the coasts than was shown in the shematic map by E. A. Tikhomirov, and moreover they occupied a considerably larger area of ice (Figure 4). 14.8

In the waters off Sakhalin the harbour seal was found in three regions: off the north-eastern coast, in Terpeniya Zaliv and in Tatarskiy Strait. Accumulations of this seal were very small and were situated relatively distantly from one another, the main whelping patches being noted in the Tatarskiy Strait. Off the eastern coast of Sakhalin whitecoats of the harbour seal were scarcely encountered at all, while in the Terpeniya Zaliv there were few of them. In 1968 in the Tatarskiy Strait the ice broke, up early, in connection with which the harbour seal whelped, evidently, in a very limited area of broken ice in the region of Cape Tyk. Here the concentration of the animals was found to be so high, that within the field of view there were observed several hundred animals simultaneously. It was impossible to determine the density of the animals per square kilometer, though visually the total number of harbour seals (together with the whitecoats) was determined to be 7 - 7.5 thousand head. In 1969 in the Taarskiy Strait there was much ice and it held up for a relatively long time, and therefore the harbour seal was disposed in a dispersed manner, the density of the accumulation did not exceed 0.6 animals per square kilometer. It should be noted that the animals were disposed closer towards the sea side of the ice.

SPRING MIGRATIONS OF THE SEALS 95

P. G. Nikulin (1937), G. A. Pikharev (19)4.0) and S. P. Naumov (19)41), who studied the distribution of the seals in the south-western part of the Sea of Okhotsk, called attention 149 to the fact that the numbers of animals in this region are augmented by the influx of these seals from more northern regions. They proposed that patches of seals are brought in on 96 the ice from regions situated to the north of the Islands of Reyneke and Men'shikova and to the east of the Shantarskiye Islands. At the same time S. P. Naumov (1941) indicated that the ringed seal did not move down into the region of the Shan- tarskiye Islands from the Penzhinskaya, Gizhiginskaya and Yamskaya regions. Meanwhile E. A. Tikhomirov (1961) considers that both the ringed seal and the ribbon seal are carried down by drifting ice towards the Shantarskiye Islands and the Sakhalinskiy Zaliv from the whole of the northern part of the Sea of Okhotsk. Our data indicate that all species of Okhotsk seals with the onset of the intensive breakup of the ice, i.e. in the first half of May, accomplish active migrations into those regions where the ice remains more stable, and moreover the animals frequently migrate , in a direction opposite to the drifting of the ice. Thus, on the 11- 12th May 1969, under the influence of hurricane-strength west and north-west winds, • o the ice situated in the region of 55° 30 - 57 lat. N. and 143 - 151 ° long. E. and to the north of this began to break up from the side of the sea edge and was rapidly carried in the direction of the western coast of Kamchatka. It would seem that the ribbon seals, harbour seals and ringed seals which had been found there just previously (8- 10th May) should have moved together with the drifting ice, but the observations from the airplane, that were made on May 13- 1kth, showed that 15 0 the seals had moved towards the north and north-west coasts of the Sea of Okhotsk, where the hurricane, which had passed, had broken up the fields of white ice and where the animals could move freely into the ice. In the region of Sakhalin, under the influence of the prevailing north-west winds and the permanent currents, the ice drifts in a south and south-eastern direction, while the seals move towards the north-eastern shores of the island and into the Sakhalinskiy Zaliv. In April of 1969 in the Tatarskiy Strait the ice was being carried to the south under the influence of the wind, but, according to observations by V. G. Gol'tsev and G. M. Kosygin (verbal communication).who were working here on the schooner "Sanzar", harbour seals together with the whitecoats were moving alray into the tightly packed mass of light floe ice which was located to the north. Every year in the second or last third of May the ice in the Sea of Okhotsk separates into two large isolated masses. One of these remains in the north and north-west, while the second remains in the region of the Shantarskiye Islands and the Sakhalinskiy Zaliv, including the north-east coast of Sakhalin. Some of the seals move off to the north from the whelping patches, others migrate into the south-western region. At the end of May - June the area of ice is rapidly reduced. At this time the seals do indeed move with the drifting ice, since there is now no other ice. 151

THE NIIMBERS OF SEALS

Studies during the last few years have shown that, as a result of the intensive commercial exploitation, the stocks of seals have begun to decline (Fedoseev, 1964., 1965, 1966; 97

Shustov, 1965; Tikhomirov, 1969). Tvioreover, one of-the most important questions, the determination of the population numbers of the animals, on which the permissible levels of the catch are based, is far from being resolved.

Applying bio-statistical methods for treating the data, we determined the population numbers of the ringed seal in the

Sea of Okhotsk in 1966 as 800 thousand head (Fedoseev, 1966).

The results of the aero-visual survey of the seals, carried out in the last years (Table 1),.permit us, to some extent, to check the :.o.l; ulKtions which we made of the population nu.^r- bers of the .ringed seal and characterize the size of the populations of the other species.

Table 1. The population numbers of seals in the Sea of Okhotsk,. according to data from the aerial survay, in thousands. T.n6sntta 1

HHLIM1t a3P0ytICTa, TbIC. r0f06 tINC iCFIHOCTL T108CHCi1 B OXOTCKOht M1toOe, n0 Z(a Ringed Bearded Ribbon Harbour per^.od of Jlaara i:p^tia a Jiapra $pc^in } tcra I I seal surveY__ Sét^âo^ . sea^. I. sea^ ^ 89* 671° Anpe.11, 1968 r. April 818 179 64* 168 Anpem, 1969 r.Apr].1 583'• 199 133 lUU 111aït 1969 r. way 865 71

saaex

^ These data were obtained on the basis,of an incomplete inspection of the seal patches. 152

Table 1 shows that the numbers of the different species are not uniform in different years and periods. This was due, primarily, to the fact that sometimes, because of unfavourable weather, incomplete inspections of the seal patches were conducted. Thus, in 1968 we were unable to inspect the central north-western part of the Sea of Okhotsk within the coordinates 55° 30' - 57° lat. N. and 143 - 151 ° long. E., where, as was shown by the observations in 1969, there are formed whelping patches of the ribbon seal and the harbour seal. In 1969 constant fogs interfered with the conduct of the survey of the ribbon seal on the ice located 70 - 100 miles from the eastern coast of Sakhalin. A complete inspection of the hauling out patches of the ribbon seal could be carried out only in May of 1969, and therefore the data on the ribbon seal survey in May most completely characterize its population numbers (133 thousand head). The population numbers of the harbour seal should be assessed on the basis of the results of the April survey in 1969, since in 1968 the inspection of the hauling out patches was incomDlete because of the reasons mentioned above. The inspection of the bearded seal patches during the whelping period in both years was complete. The results of the April surveys were fairly closes 179 thousand head in 1968, 199 thousand in 1969. At the same time in May the number of bearded seals on the ice was found to be half of the mentioned figure. It is possible that some of the already moulted seals were already in the water or were migrating into 153 the regions of the summer feeding grounds. The population numbers of the bearded seal in the Sea of Okhotsk should be assessed on the basis of the results of the survey in April, i.e. rounded to 180 - 200 thousand head. The data on the ringed seal surveys in Aoril of 1968 and in May of 1969 do not differ essentially, while in April of 1969 there were almost 30% fewer of these seals. This occurred for the reason that we did not conduct the survey off the coast from Okhotsk to Ayan, where there was grey and rind ice. On such ice, as has been mentioned above, whelping patches of the ringed seal do not generally occur, but here there may have been sexually immature animais, which readily go into regions, abounding in polynia and open patches of water. On the whole, the data of the aerial survey confirm the previously proposed value for the population numbers of the ringed seal as 800 thousand head (Fedoseev, 1966). The method of the aero-visual survey of the seals is imprecise, the error may be as high as ± 20%. Furthermore, a part of the seals during the time of the observations are always in the water. According to the data of A. P. Shustov (1969), in clear and overcast calm weather during the moulting period 83-84 5 of the animais encountered are hauled out on the ice, while 16-17% are found in the water. Since the error of the survey method itself is greater than the correc- tion coefficient for the number of animals that are in the water, it seemsthat there is no sense in intruducing this coefficient. 154

CONCLUSIONS

The observations, carried out in the Sea of Okhotsk during the whelping period (in April), showed that the distribution of the seals depends on the disposition of the ice that is suitable for reproduction of these seals, with each species having its own characteristics. The ringed seal selects for its whelping fields of firm white ice; the bearded seal, ribbon seal and harbour seal whelp, mainly, on light floe white ice in the presence of polynia and open patches of water. At the sanie time the bearded seal and harbour seal may whelp on ice fields composed of light floe white, grey or rind ice. On the thin ice around the white ice floes they make holes similar to the holes of the ringed seal. The whelping patches of the ringed seal are concentrated in the north-western part of the Sea of Okhotsk, from where in certain years they extend almost to the central northern part of the Sea. In addition, this seal whelps in Shelikhova Bay, off the west coast of Sakhalin and in Terpeniya Bay. The whelping patches of the bearded seal are confined to two regions; the northern part of the Sea of Okhotsk, including Shelikhova Bay, Kekurnyy Bay, Babushkina Bay and Tauyskaya Bay, and the eastern coast of Sakhalin, including Terpeniya Bay. The main region' of the whelping of the harbour seal is located in the Tauyskaya - Yamskaya region, from where it extends in a south-western direction to 55 ° 30' lat. N. This seal also whelps in the Tatar Strait and in Terpeniya Bay. 155

The ribbon seal whelps off east Sakhalin and in the central northern part of the Sea of Okhotsk. The breaking up of the whelping patches occurs in the first third of May, when the intensive breakup of the ice commences. At this time the seals migrate into regions where the 99 ice remains for a long time, and moreover they accomplish migrations in directions opposite to the drifting of the ice. The data from the aero-visual survey and the bio-statistical calculation of the numbers of ringed seal indicate that the population of this seal in the Sea of Okhotsk comprises 800 - 850 thousand head. The population numbers of the other species, according to the information from the aerial survey, comprises bearded seal - 190 thousand, harbour seal - 170 thousand, ribbon seal - 133 thousand head. The most favourable period for conducting the survey of seals in the Sea of Okhotsk is from April 10th to May 20th.

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4 01 159

UDC 599.745.3 L. A. Popov

THE CAUSES AND DIMESSION'S THE NAT-uRAL MORTALITY OF 100 YOUNG HARP SEA1S.bühiNd THE LACTATION PERIOD

The post-war lYéribd 6i' the àommercial exploitation of the harp seal in thé béâ:à àf thé Noah Atlantic is characterized by the greatly increàéed àâtéh àf the young- animals, the fur pelts of which are in gréât àéMàfid bn international and domes- tic markets. The c O- Mbéi"ciài- ifitèrést in obtaining the greatest amount of the valuablé fUr râw Material was the basic stimulus for the development ôf the ààntémporary sealing industry for the harp seal in thé frégibnâ àf Néwfb-undiand, Jan-Mayen, the Barents and White Séab4 As a result ôr Ihiâ --trând in thé catch, the numbers of newly-born young tâkén àaît1MérCial sealing are very great and, consequéntl5i; ibéêâiiàé bi; thé remaining small reserve, the yearly repleniâhbênt.bf cks Cf harp seals occurs at slow rates. Thiâ eiéà to àiàrm about the state of the seal stocks, whiéh; in âi51U ban against catching • adult females and eékiiàii ààimàis, continue to remain under stress. Thuâ4 tihdér fi E6hà1:Ei6nà in which the contemporary sealing is bêihg anaiiaëài in ààdition to the existing measures for proteétihg ihé àêàià; théré are needed also supplementary measures, in i)artiduiàr.- thé introduction of rational quotas for the éa th àf SiCknè ééais In resolving thi àoMPlék 4uestion, a knowledge of the dimensions of the natürai 1Itràf the seals and, in particular, of the newlybon OUng- aCquires no small significance, .160 all the more so since up to the present time there exists also a biological basis for the extensive hunting of these seals. This is manifested in the theory of the "cancellation by the. sealing of the high natural mortality of the young harp seals", which alledgedly occurs especially in the course of the first year of life of the animals. Since this theory is based exclusively on assumptions and is not supported by any factual data, it is natural that a study of even a part of this question is of undoubted interest. It is known that young harp seals lead a great part of their first year of life outside the field of view of investigators. Therefore the collection of scientific information on the causes and dimensions of their natural mortality is, in practice, possible only during the period of lactation and moulting, i.e. when the animals form concentrated but temporary patches on the ice. For the White Sea stock of the harp seal this period is marcu. Therefore the collection of the scientific material was also accomplished during the course of this month at the time of the drifting of the biological stations "Toros - 1 - 2 - 3" in the White Sea in 1966 - 1968. In the course of these three seasons, when scientific workers were drifting on the ice together with the patches of seals, along transects and in sample areas there were conducted inspections, weighing and counts of the young seals, and determinations of the causes and dimensions of their natural mortality. In all there were studied more than 3000 seals. At the same time, on the basis of the visual observations, the effect of the ice conditions in the different years on the survival rate of the young seals was determined. 161

We find information on the presence on the ice of stillborn young and of abnormally developing pups, called °starvelings" , in the studies by N. A. Smirnov (1927), S. I. Ognev (1935), S. V. Dorofeev (1936), K. K. Chapskii (1937) and several other investigators, who studied various questions of the biology of the harp seal in the White Sea during the period of reproduction. The fact of the finding of stillborn young, which had not freed themselves of the foetal membranes, was also confirmed by our data. Moreover, they are also supplemented by repeated observations on the birth of dead pups. Leaving aside the analysis of the causes of the birth of stillborn young as a question which requires special investigation, it should be noted that this phenomenon is common and is constantly observed. It is generally known also that the occurrence of emaciated young or "starvelings" is a result of an abnormal course of the

- lactation period, when the females which have whelped, because of some physiological or pathological causes, either completely stop feeding the young or provide the young with an inadequate amount of milk during the course of the entire period of lactation. Un the basis of the material collected it becomes possible to elucidate several questions concerning the occur- emaciated rence of .11telge« young in greater detail. Firstly, the fact should be noted that certain females do not commence feeding their pups after whelping. Initially after the mass whelping of the females it is difficult to distinguish such young by their external appearance from the main mass of pups, whose lactation is proceeding intensively. After 2 - 3 days, however, they begin to be clearly distinguishable 162 by such superficial features as a gibbosity of the spine, an enlarged head and sluggish movements. On dissecting such pups a complete absence of the subcutaneous layer of fat was noted. In order to elucidate the changes in weight of such young animais and the effect of the emaciation on their life span, a group of animals was put under observation at the beginning of March 1968. Included in this group were pups 102 in which the process of emaciation of the organism had already progressed for 1-2 days and in which the initial weight of

the body (on March 6-7th) had ranged from 8 to 11.1 kg. 3- k days after the commencement of the weighing the results of the emaciation were superficially clearly evident: the animals became relatively immobile, they reacted sluggishly to touch, the gibbosity of the spine became much more marked, on the body there appearea transverse folds of skin and the fur became dull. The young animals lost weight daily (Figure 1), with the greatest loss in weight being noted on the first days of life. The total weight loss in the first two young pups over 7 days comrised 2.0 and 2.3 kg, in the third over 8 days it was 3.3 kg. Simultaneously daily weighings were made of a control pup, the mother of which was shot after a day's feeding. This pup was born on March 7th and was first weighed on March 8th: its weight was 10.7 kg. The greatest loss in weight in the control pup was also noted during the first days (600-800 gm per day), while later this decreased to 200-300 gm per day. After 8 days the weight of the pup decreased from 10.7 to 7. • kg, and the total weight loss comprised 3.3 kg. 1 63

Weight_, kg I .... /0.[ \ \.....›..\ .9 NN \•••• .7‘,. .8 ... \ N. \ . `-...., ''....

" P '31 l 6 Ycno7 89 8tible e .oeravia./e/fue:" e l irys (It is apparent from .r• -••• -• eeMelibILUU, iraou.semnble Cam/re/NU the text that these ci'emembne, mama Kornapo?0 °meinPe - n bers ripria refer to the date in March.)

• Pite. 1. Hamel-mime Beca fteTeubitnen, norm1- 11.111X OT IICTOLUO110 Figure 1. Change in weight of pups, which died from . emaciation. Legend: — pups, abandoned by females Pup, the mother of which was shot.

In the pups which . had been abandoned by the females immediately after birth the lethal outcome occurred at a weight of 6 - 8.8 kg, i.e. considerably less than that at birth. The age of the dead animais ranged from 9 - 10 days. The pup which had fed for a day was still alive on the tenth day but was found to be immobile. Thus, the results of the conducted experiment allow one to consider that the pups,abandoned by the females immediately after birth and.after the first days of lactation, die of emaciation within a short space of time. Since our numerous observations confirm the existing opinion that other females do not feed young animais which have been abandoned 165

On the basis of the examination of a considerable number of pups it was also established that their death occurs as a result of serious traumas. On more than one occasion there were found pups with an extruded intestine, bitten off front flippers, lower lip and lower jaw, or with torn out eyes. Evidently, corne of these traumas were inflicted by the females at the time of birth and some during the course of the lactation period (especially the injuries to the mouth cavity). As a rule, in the young seals there are also found less severe traumas, which do not lead to a lethal outcome: deep, bleeding wounds on the back, neck, head, snout, at the base of the hind flippers, injuries to the eyes and others. Such traumas are inflicted not only by the females during the period of lactation but also at the end of this period by adult males, who begin to chase away the pups from the females with the approach of the mating period, inflicting injuries to the pups with the sharp claws of their flippers. Thus, on the basic of the investigations which were carried out, it becomes possible to distinguish the following causes of the natural mortality of the young seals during the course of the lactation period: still-birth, emaciation and traumas. Of course, the study of the dimensions of the mortality of the young seals from these causes presents a definite interest, primarily from the point of view of establishing the dimensions of the natural loss of the young stock. It should be noted that in the existing Russian literature the question of the dimensions of the natural mortality of the pups of the harp seal during the course of the lactation 166 period has scarcely been elucidated. Thus, K. K. Chapskii

(1937) mentions the presence of a "high natural mortality of the pups" in the White Sea stock of the harp seal. In later studies (Nazarenko, 1964.) we also find general data on the mortality of the young at a value of 7.5io, without a presenta- tion of factual material and without a detailed analysis of the causes of the mortality.

As has already been noted, for the purpose of establi-

shing the dimensions of the natural mortality of the pups there was employed the method of transect counts of the animals, and

the percentage of dead seals was dete.rmined in relation to the

number of animals counted. The count of the stillborn pups was generally carried out in the first days after the mass whelping of the females, while that of the emaciated and trau-

matized pups was conducted during the course of the entire

period of lactation.

In 1966 the count of the stillborn young was carried

out on March 3, 5, 6 and 7, and the relative number of dead

pups out of the total number (567 head) comprised 1.1% on

average. Later there were counted the pups which had died from emaciation and traumas, and the percentage mortality from

these causes (mainly from emaciation) in relation to 523 ani-

mals comprised 2.7% on average, varying from 1.8 to 3.31 on

different transects.

In 1967 the very open pack ice did not permit the

setting-up of protracted and permanent transects for counting

the seals. Thereforè the count of the pups was made on one

occasion, on N:arch 8th, when on the ice there were found only 167 stillborn pups. From the total number of seals counted on three transects (461), the relative number of dead pups comprised 0.9%. In 1968 the count of the stillborn pups was conducted on March 4th and 7th, and out of the total number of seals counted (629 and 245 head) the percentage mortality comprised 0.8%. On March 7th, besides the stillborn pups there were also found pups that had died of trauma: out of the total number of 245 seals the relative number of dead from this cause comprised 1.2%. Since pups that had died from emaciation were most frequently encountered in the middle of the lactation period, then in relation to the number of pups counted on the 12th of VArch (266 seals) and on the lkth of March (268 seals) . the natural mortality from this cause correspondingly comprised 1.0 and 1.1%. The summarized data on the dimensions of the mortality 105 of the pups from the various causes are presented in Table 1. As is evident from the presented table, the relativè number of stillborn pups during the course of the entire period of study varied within the limits of 0.8 - 1.1%, i.e. it remained fairly constant from year to year. At the same time the observations showed that, for example, the number of pups that died as a result of traumas in 1968 were somewhat greater than in 1966. It is evident that subjected to the greatest fluctuations were the dimensions of the mortality of the pups as a result of emaciation, since the normal course of the lactation Period may be negatively affected not only by pathological and physiological changes in the organism of the females and pups, but also by ecological factors and, above all, by the state of the ice conditions.

168

Table 1. Dimensions of the mortality of pups from various causes.

o Paameint rn6ean ReTenbnneil no paanlinu .npunnnam L. . Time of ,Ille.le Illel«AVIV:. ?f, ..: lipema ptela Bcïeroo trt arelno –137:7—"e\-27;I : L ..;.'r''.r..' '..it CLee't C7\ LAU'''. el --1.Di-e eue 0"''C 11CTOIIICIIIIII OT TfàtIM I Been) count counted 2 l c d e _ ,___ 3— 7.03.1966 : . 576 1,1 ,.. — _ 2,7 .(3,8 9-12.03.1966 - - • 523 — _ _ 8.03.1967 461 0,9 _ _ 4.03.1967 629 0,8 ____ 7.03.1968 245 0,8 1.2 _ 1.2.03.1968 ' 966 • • 1,0 - • A:1 .) ___ ___ 14.03.1968 268 1,1 . ('V.

A. - Including dead , % b - stillborn c - from emaciation d - from traumas e - total.

Thus, the materials collected during the period of work of the "Toros - 1 - 2 - 3" expeditions permit one to say that at this stage of the investigation one may accept a figure for the annual natural mortality of the pups during the lacts- tion period (from the causes mentioned above, but without taking into account the mortality of the pups as a result of the effect of the ice conditions) at a level of 4 - 5%. It is widely known that during the course of the lactation period some proportion of the pups die as a result of the breaking up of the ice sheet. Because of the specifics of the hydrological regime and of the meteorological conditions, the manifestation of the action of the ice sheet in the White Sea on the mortality of the pups is very diverse. 169

This includes the general state of the ice before the commence-

ment of the mass whelping of the females, i.e. its thickness

and dimensions, the direction of its drift under the influence

of the winds and main currents into this or that part of the

Sea, the constant effect of strong tidal currents, the presence

of local currents et al. All of these factors determine fre-

quent and strong compaction of the ice and also the openness 10b

of the ice cover.

Thus, the intensive breaking-up of the ice, on which

the seal patches are found, is a constant factor but its

effect on the dimensions of the,mortality of the pups may not

be uniform even only during the course of the lactation period

in the life of the seal. It should also be noted that it is

impossible to establish the dimensions of the mortality of the

pups as a result of the breakup of the ice or the overall

changes in the ice conditions and to express these in any

figures at:this stage of the research studies. This is con-

nected with the great difficulty in the methodological approach

to the resolution of this question. Therefore, only on the

basis of observations conducted on the ice, among the seal

patches, is it possible to form only a relative opinion on the

influence of the ice conditions in different years on the sur-

vival rate of the pups. Consequently, the results of such

observations may also be used as a basis for anapproximate

relative evaluation of the influence of the ice conditions.

In our opinion, this evaluation of the mortality of the pups i' may be expressed by such criteria as "within normal limits", "adverse" or "very adverse", if we are speaking of a greatly 170 increased mortality of the pups. The collection and analysis of such observations, in an attempt to give a relative evaluation of the influence of the ice regime in the White Sea on the survival rate of the pups in 1966 - 1968, were made by the "Toros - 1 - 2 - 3" expeditions. In March 1966 the females whelped an firm hummocky ice fields and light floe ice 50 - 90 cm in thickness. As a result of the action of north-east winds and tidal currents the ice cover constantly broke up, there were noted cases of strong hummocking of the ice, but as a whole the breakup mfxthe of the ice cover was not of an intensive character (Popov, 1966). Although pups that had died as a result of the ,compaction of the ice were not noted, it may nevertheless be assumed that some number of these may have died at times of strong hummocking, especially those pups which were situated near the edges of ice floes that were small in area and less sturdy. Taking into consideration that the main ice cover was composed of firm ice, the dimensions of the mortality of the pups during the course of the lactation period may be characterized as "within normal limits". During the course of the entire lactation period the drifting of the seal patches occurred mainly under the influence of north-east winds directed towards the basin of the Sea. After the termination of the drift of "Toros - 1" at the end of March there continued over the White Sea winds of a northerly and north-easterly direction. Therefore the accumulations of young animals, which had changed over to an independent way of life, drifted to the south in April and were 171

found to be carried out into the center of the basin of the o Sea and also into the regions of Kandalakshskaya, Onezhskaya and Dvinskaya Bays. At the same time, as a result of the action of the northerly winds, the ice cover was markedly consolidated and both the basin as well as the neck of the Sea were found to be tightly packed with close pack ice. It is natural that in the existing small patches of open water the young seals were unable to pass into the southern part of the Barents Sea, where they generally find favourable conditions for independent feeding. Practically all of the young stock born in 1966 remained for an extended period of time in the White Sea, in a region with a poor food base. At the end of April and the first half of May, with the beginning of the breakup of the ice and the appearance of spaces of open water, the young seals were noted in masses off the coasts of Kandalakshskaya, Onezhenskaya andDvinskaya Bays. In their search for food the seals appeared in regions of accumulations of fishes, where they got caught in nets and died, they emerged onto shore, accepting woody vegetation as open water, they moved up into rivers for a considerable distance and were observed near settlements. Numerous cases were observed of the death of the young seals from emaciation. Although many of the dead young seals were not found, nevertheless some idea of the dimensions of their mortality may be formed on the basis of the recovery of tags.. Thus, out of the total number of pups that were tagged in March (598 head) the recovery of tags at the end of April - beginning of May comprised 3.5%. 172

Thus, while during the course of the lactation period the dimensions of the mortality of the pups may be characterized as "within normal limits", the abrupt change in the ice conditions in April-May (the covering of the neck of the sea with dense ice as a result of the action of the north winds) led to an increased mortality of the pups that had changed over to an independent way of life. On the basis of the data on the recovery of the tags, of the observations made by scientific workers of the Northern Branch of PINRO and numerous reports from local inhabitants along the coast of the White

Sea on the behaviour of the young seals, the overall effect of the ice conditions on the survival rate of the young stock born in 1966 may be characterized as "very adverse".

Observations on the ice conditions in 1967 could be accomplished only in the first half of Ma.rch. These were characterized by the absence of large ice fields and light floe ice. The female seals were compelled to whelp on very light, mushy, thin ice and on small floes. The warm weather, strong southerly winds and tidal currents promoted a permanent and intensive breakup of the ice cover (Popov, 1967).

From observations it was noted that a few days after the whelping there were sometimes encountered on the ice females without pups but with indications that they had born young, and also crushed and broken-up ice floes with blotches

of fresh blood. Although there were not found any pups that had died as a result of compaction of the ice, the presence

of parous females without pups and also of crushed floes,on which whelping had taken place, provide grounds for assuming 108 173 that cases of mortality of the pups were not rare during the time of the wind-caused hummocking of the ice. However the main adverse effect on the survival rate of the pups was exerted by the constant thinning of the ice cover, which lasted over the course of the entire period of lactation. Under the influence of the strong winds and ebb currents the ice mush and and fragile floes broke up, and many of the pups, especially those that were helpless in the first days after birth, found themselves in the water and some of these died as a result of waterlogging of their dense hair coat. By means of observations from the air, which were conducted at the end of the first half of March, it was established that the melting, breakup and drifting out of the ice in a northerly direction were proceeding so intensively that the neck of the White Sea had become practically free of ice cover. Such ice conditions were bound not only to have led to an increased mortality of the pups, but would also have promoted an abnormal course of the period of lactation and, consequently, an increase in the dimensions of the mortality of the pups as a result of emaciation. In giving an overall evaluation of the effect of the ice conditions on the survival rate of the young stock born in 1967, it may be assumed that these conditions were closer to the criterion of "adverse". In March of 1968 the ice mass in the White Sea was composed mainly of light floe and very light floe ice, rind ice fields and floes up to 30 - 40 cm in thickness. In contrast to 1966 and 1967, pronounced deviations in the hydrometeorological conditions were not noted. Under the influence of the southerly winds and tidal currents there was noted only 1711, a constant hummocking of the ice. Subjected to the strongest breakup during this period were the fragile very light floe ice and the rind ice fields, along the edges of which were situated females with pups. During an inspection of a seal patch there was founde for the first time, a dead pup that had been crushed between hummocks during compaction of the ice (Popov, 1968). Since the strongest and most frequent compactions of the ice occurred in the middle of the lactation period, when the pups had become stronger and could haul themselves out of the water independently in cases of breakup of the ice cover, we do not have at our disposal any facts which would indicate that there was a very adverse effect of the ice conditions in 1968 on the survival rate of the pups. Even if one takes into account that some of the seal patches were swept through the Kedovskie and Goryainovskie shoals, the effect of the ice conditions was not as adverse as was the case in 1967, and even more so in 1966. If one were to attempt to give any relative evaluation, this would be closer to the criterion of "within normal limits" than to that of "adverse". On the basis of the observations made in 1966 - 1968 it seems possible to conclude that the relative dimensions of the mortality of the pups during the course of the lactation period could fluctuate markedly under the influence of the ice 109 conditions in different years. Various changes in the ice cover, occurring as a result of the action of various hydrometeorological factors, could affect to varying degrees the dimensions of the natural mortality of the young stock of seals. 1'75

Above all, it should be noted that the fragmentation and breakup of the ice only during the flood and ebb tides does nct affect the mortality of the pups to such a considerable degree as has been presumed until recently. Most dangerous is the combination of these factors with constant and strong winds, which provide conditions for additional wind hummocking of the ice or for the rapid fragmentation of the ice. It is the combination of these factors which may lead to a sharp increase in the dimensions of the natural mortality of the pups. Strong and constant winds may also cause such marked changes in the ice conditions, like those which occurred in 1966 and 1967, that led to a considerable mortality of the pups. Undoubtedly, the most adverse effect of all of the hydro-meteorological factors is manifested during the first days after the birth of the pups and considerably less so in the middle or at the end of the period of lactation.

REFERENCES

• . TIHTEPATYPA - . ■ TIO- 1 RomOm C. É. Mani) Ilanbl 110 peruomy nepuo,a, ,r uz11311n rpennemacKoro mewl. Tpy.tili lio.upnori uomuccuu, Emu. 31, 1936. . 4 11a3apetmn 10. 11. .McrIcuue 6c.lomopc1wr0 .1bicynn u esaunmè 110 CCTCCTI3C11110i1 C111CpTlIOCTI1 1‘10.10,RIIM1. T0311C1,1 7,0E."111,11,011 oeC.C1111 I'veruoro coueTa Kapc..-mcKoro OT egentiff FOCIIIIOPX. IleTponuoncK, 1964. Once C. 11. 3bcpu CCC1) 11 npu.nmaluitx cTplul. T. 3, M., 1935. • Ilonoo •11. /1. Ha .11,;.(une c Tioaensum «Ilpupo.a.a», ..1\12 9, 1966, flown .11. 21. 13:;cn ur Ju.;:ne c 'no:mu:mu. 1-1pupo.3.il,>, ,.N.9 10, 1967. 110n08 .11. A. Rperul) «Topoc-3». ellpupota», .1.\2 11, 1968. C,Ittipmoe 11. A. Pici-aeilonatinsi iia.a npombicaom ' (5e.1omopcuciro Tioacun. Ho- .13CiIIIIIIC na.6./uo.u.cunu ua:i.. 6e.1omopcizum abicyuom. Hance-run mute.la npluza. nx.- T110.1,,_ T. 6. 111,111. 1, 1927. 0 'Muck:Eta K. 1(2 FIcenuonainist 6emomopcKoro cTaaa rpcmialucizoro Tioicun 13. 1937 roRy. «I1po6.1eNt1 Apx-ruKu», Np. 2, 1937. 176

1. Dorofeev S. V. Information on the period of infancy in the life of the harp seal. Trudy Polyarnoi komissii (Transactions of the Polar Commission), issue 31, 1936. 2. Nazarenko Yu. I. Tagging of the White Sea harp seal and data on the natural mortality of the young stock. Tezisy dokladov sessii Uchenogo soveta Karel'skogo otdeleniya GOSNIOREh.* (Reports of Proceedings of the Session of the Academic Council of the Karelian Branch of the State Scientific Institute of Lake and River Fisheries). Petrozavodsk, 1964. 3. Ognev S. I. Animals of the USSR and neighbouring countries. vol. 3, MOscow, 1935. 4. Popov L. A. On an ice floe with seals. "Priroda" ("Nature"), No. 9, 1966. 5. Popov L. A. Once again on an ice floe with seals. "Priroda", No. 10, 1967. 6. Popov L. A. The drift of "Toros-3". "Priroda", No. 11, 1968. 7. Smirnov N. A. Studies on the commercial exploitation of the White Sea seals. The latest observations on the White Sea harp seal. Izvestiya otdela prikladnoi ikhtiologii (Proceedings of the Section of Applied Ichthyology), vol. 6, No. 1, 1927. 8. Chapskii K. K. Studies on the White Sea stock of the harp seal in 1937. "Problemy Arktiki" ("Problems of the Arctic"), No. 2, 1937.

* Translator's note. GOSNIORKh Gosudarstvennyi nauchno- issledovatel'skii Institut ozernogo i rechnogo rybnogo Khozyaistva. 177

UDC 599-74-5.2 V. I. Krylov

THE FEEDING OF THE PACIFIC WALRUS 110 (Odobaenus rosmarus divergens,,Ill.)

The literature on the biology of the walrus, both Rus- sian as well as foreign, is fairly extensive but the feeding of this animal has not been adequately studied. Most investigators (A. I. Malmgren, 1864; M. W. Elliot, 1882; 0. Nord- gvist, 1883; Romer und Schaudin, 1900; H. Winge, 1902;- N.

A. Smirnov, 1908, 1935; I. I. Gapanovich, 1923; V. K. Arsen'ev,

1927; A. Pedersen, 1931, 1962; L. I. Leonov, 1954; I. L. Buckleu, 1958; A. W. M.ansfield, 1958, 1960, and others) mainly

only list the representatives of the benthic fauna, fishes and

even some warm-blooded.animals, which were found by them in

the stomachs of the walrus. K. K. Chapskii (1936) and V. T.

Tsalkin (1937) examined the feeding of the Atlantic walrus-in

greater detail. This question was studied in a more thorough

manner by P. G. Nikulin (1941), who was the first to present

data on the qualitative composition of the food of the Pacific walrus. However, on account of the small amount of material,

the lists of food objects which he presented are not.exhaustive..

Our aim, using our own material and the literature data,

was to attempt to compile as complete as possible a list of the food objects and to shed light on the question of the quan-

titative composition of the food of the Pacific walrus.

The material was collected by the author during the

period 1960 - 1963 in the north western part of the Chukchi

Sea (in the region of Wrangel Island). 650 walrus stomachs 178

„ were dissected, of which only 35 contained food that was in

a state.that made it possible to determine its composition.

In 62 stomachs the contents had been so strongly digested

(chyle) that it was found to be impossible to determine its

composition. The available material is, of course, insuffi-

cient for a detailed characterization of the feeding of the

Pacific walrus, but it permits us to extend our knowledge on

this question.

The identification of the food objects, found in the

walrus stomachs, was carried out with the cooperation of Can-

didate of Biological Sciences Ya. I. Zhitlo, a hydrobiologist

with the PSagadan Branch of TINRC, and the participation of

other hydrobiologists and ichthyol.ogists of TINRO.

As a result of the analysis of the 35 samples, the

following animals were found (Table 1). About 10 species of benthic animals in our list had

not been found by previous investigators. From Table 1 it follows that molluscs occupy the main 111

place in the feeding of the Pacific, walrus. P. G. Nikulin

(194-1) indicated that small molluscs of the family Astaridae

predominated in the food of the walrus, but in our samples

these species were not found at ail. We also did not find.

the three species of molluscs of the genera Saxicava and

Buccinum,which N. A. Smirnov (1908)9 V. K. Arsen'ev (1926)

and V. I. Tsalkin (1937) indicated as being the species that

were most frequently consumed by Pacific and Atlantic walruses. 0 Mansfield (1958) writes that the main food of the Atlantic 112 walrus in the Canadian sector of the Arctic consists of the

mollusc Macoma calcarea. 179

Table 1. Food objects of the Pacifie walrus (according to the author's data).

T a 6 .n u it a 1 061ertrbr nuTarma Tfixowreaucrroro raoprza (no p,aumem awropa)

Maxcintym Bcrpegaemocrb 06tnee malt- Bec oErbektrou 06-bexibt ;Ke.nyatiax 4eCTOO 061, ob'bex-rou, B 0:11tONI Objects A. exs, BUT. d. >xencexe Molluscs MO4JUOCICU Macoma calccica 13 423 910 110 Nucul a tennis 5 250 170 Troc.•hidae (Margarites) 6 315 Ioldia hyperborea 5 273 113 200 Mactra 5 56 160 27 Thyasira Ilexuosa 3 95 25 Mya truncata 1 • 5 5 Octopus californicus 1 1 Worms • gepon Priapulus caudatus 12 106 405 18 Echiurus echiurus 3 50 .■•■••• Onuphis concDylega 1 4 4 Ascidlans • cqua tut Pelonala corrugata • 6 425 260 247 Cueumaris sp. 1 60 55 60 Tethyum aurantiurn 2 25 90 15 o Crustaceans Pab:006pa3fibie 130 40 100 Garnmaridac - 2 Hyds coarctatus 2 20 et) 18 Chionoecetes opilio 2 20 50 20 Mysidae • • 2 8 5 Pandalus • ..- 1 . 5 5 2 2 1-lippolytidae • 1 Nectocrang,on lar 1 .3 3

• Fishes _P bl_ bl Blennidae • 8 8 Lumpenidac • 1 2 2 Alopmse imcKotzuratouiué• 3 •■■• ■•■■••■ Marine mammals •

A. - Frequency of occurrence in the stomachs B. - Total number of objects, speciMens C. - Weight of objects, gm D. - Maximum number of objects in one stomach.

Most frequently encountered in our samples were small bivalve molluscst Macoma caléarea, Nucula tenuis and Ioldia hyperborea, and of the large molluscs - Mactra. Occupying a 180 comparatively large place in the food of the walrus are gastro- pod molluscs of the family Trochidae. It seems that these species are the most numerous in the studied region of the Chukchi Sea (the region of Wrangel Island), which also explains their predominance in the rations of the walruses. Of the cephalopod molluscs only the Californian octopus (Octopus californicus) was encountered. It should be noted that the last 4 species (Ioldia hyperborea, Mactra, Trochidae and Octo- pus_ californicus) were found for the first time in the stomachs of walruses, and that only a single specimen of Octopus californicus was found. It is qui-te probable that it was caught accidentally together with the basic food. The second place in the. frequency of occurrence in our list was occupied by worms, of which the priapulids (Priapuli- dae) predominated over the remaining species, which is in accordance with the data of P. G. Nikulin (1941). More rarely the walruses consume the common echiurus (Echiurus echiurus). Of the polychaete worms we found Onuphis conchylega, which was àcarcely mentioned at all by previous investigators. Only in the list of Nikulin is there mentioned one of the species of the nephthys family (Nephthys), which belongs to the sanie class of polychaete worms. Ascidians and holothurians, according to the data of P. G. Nikulin (1941), are found in the food of the walrus in very slight amounts and Nikulin puts these in last place with respect to their significance in the food. In his list he cites only the sand ascidian Pelonaia corrugata; of the holothurians he cites the sea cucumbers - Cucumariidae. 181

Mn our samples Pelonaia corrugata was encountered very freauently and in considerable amounts, while sea cucumbers were found in only one stomach. In addition to Pelonaia corrugata, we also found one other species - the purple tethyum (Itthzun aurantium) of the family Pyuridae. However this species was found in only two samples in all and in small amounts. Apparently, in this region of the Chukchi Sea it is either rare, like the sea cucumbers also, or it is less readily consumed by the walruses. The crustaceans apparently play an insignificant role in the feeding of the walrus, although 7 species were found in our samples. On the basis of the frequency of occurrence and the number of species, they may be put in second place but they are found only in very slight numbers within the food pellet and so occupy only fourth place, yielding to the worms and ascidians. In the stomachs of the Pacific walruses there had been found only one species of crustacean - Chionoecetes opilio (P. G. Nikulin, 194:1), while 4. species had been found in the 113 Atlantic walruses - Sclerocragnon, Mesidothea, Gammaridae and Hvas (Mansfield, 1958). In our materials, in addition to the above named species, there were found three more species of crustaceans. Most frequently eaten by the walruses were crustaceans of the order Amphipoda (Gamaridae) and of the order Decapoda coarctatus, Mesidotea and others). Apparently the walruses feed on fishes very rarely. In the dissected stomachs only on two occasions did we find 182 demersal fishes: a blenny of the family Blennidae (8 specimens) and two fish of the family Iumpenidae. The latter live at a depth of up to 200 m. Romer and Schaudin (1900) found in the stomach of one walrus more than 100 specimens of the arctic cod (saika) - Boreogadus saida. Pedersen (1962) states that l during the period of the mass approach of the saika to the habitats of the walruses, this small fish is a basic food of the animals. Other authors (Smirnov, 1935; Chapskii, 1936; Nikulin, 19 •1; Leonov, 1954; Mansfield f 1958) only cite these data in their studies. Thus, from the above-cited reports it follows that fish is very rarely eaten by the walrus. Apparently, it gets into the stomach accidentally or is eaten in the absence of the basic food (benthic animals) in a given region. Information on the amount of food consumed by walruses is very scarce. According to the data of Fay (1955), a six month old young walrus in captivity consumed approximately 20 pounds (9 kg) of solid plus 1 •00 - 1800 gin liquid food in a day. Other animals, 2.5 years old and weighing 544 kg, consumed approximately 60 pounds (27 kg) of food per day. The stomach of one killed walrus contained more than 100 pounds (45 kg) of food. V. I. Tsalkin (1937), who studied the walruses of Franz Josef Land, found in the stomach of a killed adult male walrus 1704 feet of Cardium groenlandieum e 431 syphons of Mya truncata and 168 syphons of Caxicava arctica. According to our data, the maximal weight of the food pellet (semi-digested food) did not exceed 5 kg. Detailed data on the weight and number of objects of the food of walruses are given in Table 1. 1 83

It is interesting to note that in the Atlantic walruses there has been revealed a feeding discrimination related to sex and age. Thus, Bruks (1954) considers that males prefer My-a clinocardium and Molpadia, while females and sexually immature animals prefer the smaller molluscs Astarta and Macoma. Having studied a large number of stomachs of the walrus, P. G. Nikulin (1941) wrote: "We have never found a different type of food than the benthic animals mentioned in the list. However, among the excreta on ice floes, on which walruses had been lying and from which they had been frightened off by rifle fire, there were found pieces of skin of Phoea hispidae 10 - 12 cm2 in sizes". Similar cases have also been recorded by us on more than one occasion. Moreover, in three 114 *cases in the stomachs of walruses there were found pieces of skin with fat of seals. The fact that walruses eat dead bodies of warm-blooded animals (seals, birds and even whales) has been reported by many investigators (R. W. Gray, 1927; V. I. Tsalkin, 1937; L. I. Leonov, 1954; S. E. Eleinenberg, 1958; A. W. Mansfield, 1958). A. Pedersen (1931) confirmed the feeding of the walrus on a seal, citing an account by a Green- lander who had observed a walrus hauling itself out onto the ice and dragging in its flippers a seal, whose belly had been cut open with a tusk. Kleinenberg (1958) retells an unusual case, observed by Arctic explorers on Golomyanniy Island (Severnaya Zemlya), when a walrus held with its fore flippers the body of a large bearded seal (Erignathus barbatus) and with satisfaction consumed the meat, ripping it withits tusks. Romer and Schaudin (1900) report on the feeding of a walrus on fulmars; Orleans (1907) writes about the eating of eiders. 1814 e V. K. Arsen'ev (1927) and K. K. Chapskii (1936) con- O sider that walruses not only eat dead bodies but also actively attack animals. Chapskii, who studied the walruses of the Kara Sea, cites a report by Tyulin, who in 1934 observed a fight between two walruses and a beluga, with the walruses being the attackers. However, Chapskii himself in 1931 observed two walruses swimming amidst a herd of belugas and did not notice any hostile actions on the part of the walruses. There is information available that indicates that belugas avoid the habitats of the walrus (W. Kukenthale, 1893). These reports are also retold by other authors (Smirnov, 1903; Gentner, 1930; Freund, 1933). Pedersen (1931) considers that evidence for attacks of walruses on seals is provided by the numerous cases of the harp seal and the hooded seal disappearing from those regions where walruses appeared. Our observations, carried out over the course of several years on the on-shore hauling-out grounds at Rudder and . Inchoun, and on the ice hauling-out places of the walrus in the region of Wrangel Island (the northern part of the Bering and Chukchi Seas), permit us to express a somewhat different opinion on the interrelationships of the walrus with other pinnipeds. On more than one occasion we were able to observe

a fur seal lying peacefully among 3 - Lk thousand walruses on the Rudder hauling-out grounds. In some cases this animal was lying in the middle of a group of walruses, in others - at the edge, but the walruses never disturbed it. Once a bearded seal

lay 15 - 20 m from a group of walruses on this same hauling-out ground and the walruses also paid no attention to it. 185

Analyzing the results of our own observations and some of the literature data, we believe that there is no basis for including the walruses among the predators, This same opinion was held by P. G. Nikulin (1911•1), who considered that the occurrence of predatory behaviour in the walrus was of an accidental character. In this connection K. K. Çhapskii (1936) wrote: "The walrus only occasionally takes a seal, apparently 115 on those occasions when for some reason the catch of its basic and characteristic food is hindered",

We consider that only certain individuals, which are very rarely enc.ountered, may be placed in the category of predators. Apparently, when these animals appear close to accumulations of seals, the latter.do indeed quit these regions.

In other cases the seals and walruses live peacefully in direct

proximity'to one another and the walruses do not manifest any

aggressive intentions. Among the Chukchi the predatôry wa1=

ruses have a special name'- "kelyuch", in çontrast to the

"ryrka", which means walrus in general; Vhis was written about

by V. K. Aren'ev (1927). L. I. Leonov (1954) studied.in detail

the question as to where the predatory walruses.come from, what

induces them to eat warm-blooded animals, and he reached the

following conclusion. A-young animal at the end of its second

year of life for some reason lost its mother. It was not yet

able to feed independently (to search out and obtain from the

bottom the buried molluscs), it begins to catch birds (nest-

lings) on the surface of the water on shoals and to eat these;

then as they grow up, they.also begin-to attack marine animals.

Our observations confirm Leonov's conclusions. The predatory 186

walruses, as a rule, frighten away seals, which reduces the catch of the local inhabitants. The Chukchi hunters recognize such walruses and try to kill them. As a rule these walruses have large sharp tusks, are less fattened and lead a solitary life.

CONCLUSIONS

The main food objects of the Pacific walrus are bivalve . molluscs of the families Astartidae, Macoma, Nucula and Mactra, as well as gastropods of the family Trochidae. The walruses consume smaller amounts of worms of the families Priapulidae and Echiuridae, and slight amounts of Onuphis and Nephthys. Ascidians and holothurians occupy an insignificant place in the food of the walrus. The main species of these are Pelonaia corrugata, Tethyum aurantium and sea cucumbers. Among the crustaceans most frequently eaten by the Pacific walruses are representatives of the orders Amphipoda and Decapoda. However, crustaceans play an insignificant role in the feeding of the walrus, since they occur in very small numbers in the food pellet. Fishes (Arctic cod, blenny) are very rarely consumed by walruses and, apparently, only in the absence of the basic food. Warm-blooded animals (seals, birds and others) are eaten only by predatory solitary walruses, which are rarely encountered. A selectivity towards the food is noted in the walrus in relation to its sex and age. The maximal weight of food in the stomach of a walrus was as much as 4.5 kg. 187

REFERENCES

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24. Romer and Schaudin. The walrus, Odobaenus rosmarus 9. (1). Fauna Arctica, vol. 1, part 1. 1900. 25. Winge H. The fauna of Greenland, Mammalia. Greenland Reports, XXI. 1902. 26. Wollebaek. The biology of seals and the seal hunt in the European Arctic Sea. Hjort and Knipowitsch. 1907. 164

for one reason or other (death of the mother, hunting, patho- logy of the milk glands et al.), then in the final analysis these young seals are doomed to die, especially if they were abandoned at the beginning of the lactation period. •The materials obtained also confirm the fact that mass hunting of nursing females may lead to a considerable mortality of the young stock. During the course of the lactation period, besides the dead pups, there are also noted on the ice young animals that are in various stages of emaciation. Generally these are pups that have been abandoned by females during the process of lactation. The degree of emaciation of such pups depends on the duration of the preceding lactation, during the course of which there was accumulated a varying amount of the subcutaneous layer of fat, since such pups are noted in the stage of the whitecoat, the ragged-jacket and the beater. It is obvious that up to the moment of the transition to an independent way of life some, apparently slight, proportion of such pups dies from emaciation, which is testified to by the facts of the finding of dead pups that were in the intensive stage of moulting. In the main, however, the pups, abandoned by the females during the process of lactation, are found in the stage of the ragged-jacket and the beater ina strongly emaciated state, and this phenomenon is fairly common. Whether such "starvelings" subsequently survive or whether the transition to independent feeding permits them to develop normally are questions for further study. It should be noted only that at the end of the lactation period strongly emaciated pups are encountered only in rare instances among the main mass of normally developed pups. Fane^ês recne> ^ CaCôâëë°°`m°°' TRANSLATION 3185 3 of 7 e, ,oa^^mê° eieeêrvee°e,eee°°a SERIES NO.(S) ser^ce ien,e^ UDC 599.74-5.2 0 V. D. Pastukhov

COUNTTNG.THE YOUNG STOCK OF THE BAIKAL SEAL 11r

In 1953 N. S. Sviridov (1954) employed an airplane to

establish the total numbers of the stock of seals in Lake

Baikal. However, as we showed earlier (V. D. Pastukhov, 1965),

the aerovisual method is not devoid of several fundamental

defects. Therefore, in conformity with the ecological charac-

teristics of the Baikal seal (its distribution, behaviour etc.)

and taking into consideration the specific features of the ice

regime of Lake Baikal, there was proposed an ice method for

making this count (V. D. Pastukhov, 1965). The essence of

this method consists not of a direct count of all of the and-

mals, which is practically impossible to accomplish, but of

counting only the lairs of the whelping females, or more pre-

cisely the breathing holes of the lairs.

The lair has the form of a semi-oval burrow in the

snow, sometimes up to 7 m in length, which at its center or

edge is connected with the water by a breathing hole, and is

in no way discernible from the outside. During the course of

1- 1.5 months after birth the young seals, hidden under the

snow in the lairs, have time to moult completely in the majo-

rity of cases. From the second half of April, under the action

of the warmth of the sun and the vital activity of the animals

themselves, the roofs of the lairs begin to collapse and the

breathing holes in the lairs become enlarged, attaining a size

of up to 3- 5^.. in 'ïn =diamet^r in D"ay. • 19 1 • Serving as the criterion of whether a particular é breathing hole was one of the breathing holes of the lairs of whelping females, and not an enlarged "diving hole" or collective breathing hole of the sexually immature animals etc., should be the presence of the greyish-yellow moulted woo1y hair of the newly born pups, that has been frozen inimthe ice to some degree or other, and also the yellowish-grey tinge of the ice from the excrements of the seal pup, which is never found at the breathing holes of other animals. Not infrequent-

ly the lair breathing hole is given away by the presence of the seal pup itself. Because of the non-homogeneous climatic conditions on Lake Baikal, the melting of the snow from the ice and, consequently, the breaking up of the lairs occurs 12 - 20 days earlier in the southern part of the lake, as compared to the northern part. The breakup of the ice cover occurs in the same sequence. At the end of April - beginning of May there commences the relativly regular emergence of the animals onto the ice, where on warm days they lie for hours beside their breathing holes. At this time the sledge sealing starts and this is also the most convenient time for searching out the lair breathing holes. For moving over the ice there was employed a "Ural-2" 22-horsepower motor cycle with a sidecar. To the motorcycle was attached a sledge with the necessary equipment, gear, fuel and lubrication materials and provisions. Three people, who were the enumerators, made up the expedition team. 1 92

From April 17th to May 15th 1966, moving from south to north, there were set up 21 transverse transects (along the short axes of Lake Baikal) of a total length of 1120 km. The total distance of the trip comprised about 3.5 thousand km. On the whole, the weather favoured the conduct of the counting work. In connection with this, the laying out of the courses was generally accomplished not by an instrumental method but by direct visual observation, based on clearly distinguishable (familiar) capes, gorges, mountain tops etc. The speed of movement on the transects generally comprised 30 - 35 km per hour, it dropped markedly on hummocky sections and, conversely, increased to 40 - 50 km per hour on the large areas of smooth ice, where whelping females do not build lairs. The passages along the shore from one transect to another were accomplished at a speed of about 60 - 70 km per hour. At times, compacted fields of hummocky ice and crevices, thermal sutures (Figure 1), presented serious obstacles to movement. It is enough to state that during the period of the 119 expedition there were forced more than 200 crevices, the width of which ranged froe 0.35 to 2 m and more. The largest number of crevices (about 90%) were overcome in the South and Central parts of Lake Baikal. The ice in the northern third of the lake was optimal for movement. The lair breathing holes and other types of breathing holes, which formed a sharp contrast against the white background of the ice, were generally noticed at a considerable distance (Figure 2). However the motor cycle continued moving along its prescribed course and stopped only on those occasions 193

Pue. 1. 111,e.nb. CPOTO aaropa Figure 1. Crevasse.

* Author's photograph

Puc. 2. 06Tasulimy' aoronmunau °Minima. ftoro aeropa Figure 2. Thawed lair breathing hole Author's photograph

when there occurred on the traverse a partly broken-up lair, breathing holes etc. After this, the distance from the motor cycle to thd lair was determined, alond a straight line per- pendicular to the course. The statistical treatment of about 100 such measurements showed that the lair breathing holes 194. were detected at a distance of 116.5 t 9•5 m to either side

of the motor cycle course, with a range variation of from 20

to 4.10 in. Since the count was always made to the right and

to the left of the motor cycle course, the width of the

counting strip comrised 223 t 19 in.

In spite of the fact that a constant effort was made

to hold as precisely as possible to the selected course, the

actual transect, in the final analysis, represented not a

straight line but rather a broken, to some degree or other,

line. This was brought about by the fact that along the path there were encountered sections of impassable hummocky ice

(as a rule, the seals are' not found on these sections) and

wide open crevasses, which required det_ours to be made. There-

fore, the length of the transects (as determined by odometer

readings) was found to be on average 16J greater than their

length as determined according to the map. It should be noted,

however, that the counting of the lairs was performed during

all such detours. Subsequently, on the basis of the known distance of 120

the transects, the width of the counting strip and the number

of lairs detected,there was first calculated for each section

the density of the young stock, or, more precisely, the area

per lair. Then the value found was extrapolated only onto that

area which belonged to the given section, i.e.. to half of the

sum of the area enclosed between the given and the neighbouring

transects (method of weighted means). The areas were determined

by a planimetric method from a map of Lake Baikal with a scale of

1 s 300000*-

* (This footnote is translated on the following page)

195

Table 1. Results of the count of the whelping lairs of females of the Baikal Seal in April- IvIay 1966. Ta6Jinna 1

Pen.TIbTaTbi pien JIM- 01311M meitimx cam« 6aüiaatoui iepnu anpue—mae. 1966 r. B n 110TE We I 1 , 10CTI. map- E • F G H A inpyrott. /CM K.M11.1e, namant, 3nmmio- MO onna- npnxnan- ,„ u„,„„„ 06mee Pnpeau C mme nmI cnna i hm ,,,,, , tio.meau J:_,, 2 •norotunu no npnmo il :elin py,"nuln" °M;:er- MOTO

2 3 5 6 7 Southern Baikal 103enblii Daiisan 1. rlominliiKa — 33 38 1 I • 8,47 1564,7 185 Mypitito

2. TOACTL111 3:3 46 2 5,13 764,8 149' Ceiiiaai 3. .7111cTiminza 36 54 12,04 694,5 Tau xoù 4. KOTIA 36 49 2 4,68 1283,3 274 Ilepeemuan

5. H. Xoblynt — 53 3 3,94 • 1529,8 388 110BopoT

6. Flectuulan — 36 42 1 - 9,37 1564,8 167 14nmœim6 cop TotalMmro 218 275 10 6,06 7401.9 1221 (ay.(cTO

A - Sections . B 7 length of transects, km c - along the straight line d - along the motor cycle path E - Number of lairs found F - Area per one lair, km2 G - Extrapolated area, km2 H - Total number of lairs

1. Polovinka - Murino 2. Tolstyi - Snezhnaya 3. Iàstvyanka Taikhoi 4. Koty Pereemnaya 5. N. Khomuty Povorot 6. Peschanaya Istokskii sor

* (Footnote from preceeding page, bottom of p. 120 of original text.) Excluded from the calculation was the area of the Maloe More Strait, Chivyrkuiskiy and Proval Bays, a large part of Bargu- zinskiy Bay and also of all the sors. In these sections of Lake Baikal the seal is practically not encountered in winter.

196

Continuation of Table 1. Ilpoito.nicenue TaChri. 1

2 3 4 5 6 7

cpea/mahmwail Central Baikal 7. An-EuxaayK •••••■• 1899,5 8. kpecl- 50 2 5,57 1462,8 263 TO.ICTIAG 9. Yxau - 47 47 •1455,4 Paccbmuoii 10. Ilwumefi -- 46 4G. 1 10,26 1656.7 162 Typtca II. Ourypent- 73 100 14 . 1,59 1909,5 1201 Te.nerna 12. Kotiepnu 50 55 3 4,09 1477,6 361 Ilaromubc • Cusrroro Hoca . 13. 110K0f111111i11 - 45 47 2 5,24 1189,8 227 MapKono . TotalI4Toro ' 350 388 •29 4,99 11.051,3 2214. ( ay.(9.) Ceeepnbill BaiiKan Northern Baikal 14. B. Coaounoubiii- . 54 I '54 . 1 12,04 1531,4 127. B. 143rmoubc. CunToro lloca 15. 3allopriTutet . 79 13 • 1,29 1612,2 1249 «Cocuona 16. Enoxim - 60 2 6,91 • 1194,5 176 ,LIsauma

17. XuCie.leu- 51 56 . 1,78 1. 125,5 632 . 51mmm • 18. Mymmuart 48 73 10 1,63 1192,5 733 Yp6nan 19. 1(0TC:1011K 0 13- 39 45 4 2,51 994,0 396 CK1111 . 111unauRa 20. Kpacubtfi 51p - 41 47 5,24 926,9 177 1.1.1upurzu 21. BafiKaabcNoe - 39. 45 ..••■•■ M14,2 XaKycbt i•oz•o 404 457 39 3,03 1 0591,2 3490 Total («ay.) Bcero 972 1120 4,19 29044/1 6925 Altogether (e).) •

7. Aya Enkhaluk 14. B. Solontsovy - V. Izgolov'e 8. Krest Tolstyi Svyatogo Nosa 9. Ukhan - Rassypnoi 15. Zavorotnyi - Sosnovka 10. Izhimei Turka 16. Elokhin - Davsha 11. Cngureny Telegin 17. Khibelen Yazovka 12. Kocheriki - N. Izgolov'e 18. Muzhinai Urbikan Svyatogo Nosa 19. Kotel'nikovskii Shignanda 13. Pokoiniki - Markovo 20. Krasnyi Yar Shirigli 21. Baikal'skoe Khakusy 197

For the Southern Baikal, with an area of 7401.9 1cm2 , the total number of lairs was 1221; for the Central Baikal (area 10,591.2 km2 ) - 2214 lairs; for the Northern Baikal (area 10,591.2 km2 ) - 3490 lairs; and in total for the whole of Lake Baikal - 6925 lairs (Table 1). We also attempted to calculate the total number of lairs for the whole lake by another, graphical method, without fiudi ng resorting to zmat uut the extrapolated areas and without calculating the density of the lairs for each section. In this case it was found important to know the total extent of Lake Baikal, expressed in the form of a straight line, the places (points) of intersection of this with the actual transects, the width of the counting strip and the number of lairs found on the sections. However the essential factor in this method of calculation is that the number of lairs should be determined along straight and not curved transects. Taking into account the fact that a sinuosity, of a more or less equal degree, was inherent to all segments of the transects and along the whole length of the transects, we considered that it was possible to make the recalculation of the number of lairs on the basis of the straight-line transects, the lengths of which were determined from the map. The extent of the lake in the form of a straight line and the points of intersection of the latter by the sections were determined by an elementary method, by joining up the centers of all of the transects, which had first been drawn onto the map. Then a conventional graph was drawn on milli- meter graph paper. Along the axis of the abscissa the length 198 of the lake was drawn, while along the axis of the ordinate (opposite to the established transects) - the number of lairs. The points obtained were joined by a smooth curve. For selected transects there was found a conversion factor - the coefficient of proportionality, and the area enclosed between the curve and the horizontal line of the coordinate was determined. The area found was multiplied by the coefficient of proportionality and in this manner the number of lairs was determined. The total number'of lairs calculated by the graphical method was: 1133 for the Southern Baikal; 1925 for the Cen- tral Baikal; 3642 for the Northern Baikal; and 6700 lairs in all for the whole lake, i.e. very close to the value obtained by the first method. Since the accuracy of the results with the presented calculations depends primarily on the precision with which the width of the counting strip was determined, then with P = 0.05 (95% reliability) the value of the annual increment of young stock comprised 6800 individuals ± 17%, on average from both methods of calculation. . Briefly analyzing the results obtained, the following may be noted. The density of the young stock (or whelping females, since each of these basà,cally produces one pup) in the meridional direction increases from south to north. About 17% of the young are concentrated in Southern Baikal, 31% - in Central Baikal and 52% - in Northern Baikal. There is also found a clearly expressed asymmetry in the distribution of the young stock according to the different basins of the lake and in the latitudinal direction. The main mass of the animals is confined to an 8 - 15 km longitudinal belt of the open 123 199

(deep-water) part of Lake Baikal, located at a .distance of

about one third of the width of the lake from the eastern shore

along the various regions of the lake. In the 6 - 8 kilometer

wide off-shore zone along the eastern shore and in the 12 - 15

kilometer strip along the western shore only an insignificant

number of whelping females with young are encountered. 4 - The literature data (Kuznetsov, 1891; Kulakov, 1898;

Svatosh, 1926; Ivanov, 1938) and also our latest observations,

made in 1967 -1969, indicate that the described character of

the distribution of the animals on the lake has remained fairly

stable from year to year in its general aspect.

Without going into a detailed analysis of this charac-

teristic distribution of the whelping females on Lake Baikal,

we will note only that it represents an integral expression

171 of the physiological state and behavioural reactions of the

animals, conditioned by the biotic and abiotic factors of the

environment during the pre-icing and icing periods.

The data obtained on-the population numbers of the new-

born young stock and on the distribution of this over the ex-

panse of the lake have a certain practical importance. For

example, it may be stated with confidence that the catch of

the young animals should be conducted mainly in the Northern

and only partially in the Central Baikal. As to the southern

third of the lake, where a decreased density of the young

stock is observed, this should-, in our opinion, be closed to

sealing operations and should serve as a reserve.

Knowing the size of the head count of the new young Il stock and possessing data on the age-sex structure of the po-

pulation and also on several other parameters of the population, 200

it is possible to calculate the size of the total stock, the

biomass and the production, and to provide an adequate basis

for recommendations on the catch levels for the immediate

future.

In the conditions of Lake Baikal, where in recent years

only the young seals are caught, providing a valuable source

of fur, a regularly performed count of the new-born young stock

(if only at intervals of the period of sexual maturation of

one generation) acquires a special importance. It should be

stated that the state of the new-born young stock and its num-

bers are indicators of the state.of the population. When the

numbers of the young stock increase there is also an increase

in the total population; when there is a decrease in the young

stock, the maternal head count also decreases, which means 41 that the total stock also decreases. A constant check on the head count of the young stock and, consequently, on the total

size of the population provides the possibility of not only

regularly introducing corrections to the yearly catch levels

but will also permit us to abandon the seal hunting (with the

numerous disadvantages that are inherent to this) and to

change over to a scientifically based system of management.

Despite the in principle valid, as it seems to us,

basis of the described method of counting, it would be in-

correct to consider that the technical aspect of its execution 124.

does not require modifications. For example, the results

would have been more accurate if it had been possible to lay

out two to three times as many transects as we were able to do.

This would be quite possible to accomplish with a group method

of study, i.e. on two or three motor cycles. 201

(lip ' 0n the basis of experience gained in 1969, the described method of on-ice counting could be somewhat modified in the future, in particular, by making the count of the lairs not along transects but on previously marked out quadrants, spread out evenly over the whole of Lake Baikal. On the other hand, it would be a mistake to overrate the importance of such transportation as the motor cycle for the counting work on Lake Baikal. The counting of the lairs, employing motor cycles, is laborious and, to a considerable extent, dangerous work, since it is carried out on the very weak spring ice, which does not withstand the weight of a normal motor vehicle. Therefore the application of motor cycles was justified only in the first stage of the investigations. In the future, however, having available data on the quantitative relationships of the lair and the other breathing holes, axe their affinity to ice of a particular character etc., i.e. utilizing that stream of information which accumulates from studies on the ice, it would be sensible to try - to change over to a similar (by means of a count of the lair breathing holes) counting of the young stock but now using an airplane (helicopter). How- ever, in order to elucidate the possibility of aerial counting (including the application of aerial photography) it would seem to be sound practice to conduct a preliminary parallel test of the counting of the lair breathing holes from the ice and from the air over the same areas. 202

REFERENCES .

flUTEPATYP.A.

• 1 Haanoa T. M. Berm:meHan Hernia (FlIcca sibirica grnelin), ce 6H000rns H npomucc.a. 11311. 6lloaoro-reorpatp. T. 8, Bun. 1-2, HpHyrcH, 1938. 2 Ky3netioa H. fi. 0 rio.aetthem npomblcae Ha Barnza.le. Becrn. pril6onpommun.. I T. 6, HMI. 2, C-116. 1891. 3 KY 11(11C06 H. E. 0.71bX011. X03SHICTBO CFO Byp1T-E.TIBIIHIIIICK0r0 H Kyry.abcHorn • BUONICTIB1, 6b113WCr0 0.1LX0IICK0:0 Be,10MCTIHI, BemacticHoro oHpyra, 1,1pHyrctroti j re-quint. 3anHcHtt Pro or 0T,11. CTaTIICT., T. 8, BIM. I, 1898. 14. Hacreoe B, fi, K MCTO,!IIIKC Honntlecreettnoro yttera 6aftHaabcHoro rtoneHH. C6. «Mopmè m.,leHorntratorune». M., el-layHa», 1965. 5 Coarout 3. 0. BartHamcHniVrto.ttettb (Pbnca baicalensis) H ripombicen ere. C6. elplIpORH H oxora». Ha,-no BceyHpanHcHoro colon OXOTIIIIKOB H pb160.10130B. • 4.pbtrort, 1926. • 0 Couptiaaa H. C. OrIbIT rtera 411C.TICHH0CTII H pacnpeagmeinto HeprnA Ha 03Cpe Barnr.az C HOMOIHIHO cammera. ass. PipxyrcH. 11H-Ta, WAIL 6, 1,1pHyrcH, 1954.

1. Ivanov T. M. The Baikal seal (Phoca sibirica Gmelin), its biology and exploitation. Izvestiya biologo- geograficheskogo nauchno-issledovatel'skogo instituta (Proceedings of the Biological and Geographical Research Institute), vol. 8, Nos. 1-2, Irkutsk, 1938. 2. Kuznetsov I. D. The sealing industry on Lake Baikal. Vestnik rybopromyshlennosti (The Fishing Industry Herald), vol. 6, no. 2, St-Petersburg, 1891. 3. Kulakov P. E. 01'khon Island. The economy of its Buryat- Elantsinskoe and Kuturskoe departments, the former 01'khonskoe'department, of the Verkholenskii district of Irkutsk province. Zapiski Russkogo geograficheskogo obshchestva ot otd. statist., (Memoranda of the Russian Geographical Society from the Statistical Section), vol. 8, issue 1, 1898. 4. Pastukhov V. D. A contribution to the methodology of quantitative counting of the Baikal seal. Sb. "Morskie mlekopitayushchie" (symp. "Marine mammals"). Moscow, Publ. "Nauka", 1965. 2 03

5. Svatosh Z. F. The Baikal seal (Phoca baicalensis) and its exploitation. Sb. "Priroda i okhotà". Izd-vo Vseukrainskogo soyuza okhotnikov i rybolovov (Symp. "Nature and hunting". Publ. The All-Ukrainian Alliance of Hunters and Anglers). Khar"kov, 1926. 6. Sviridov N. S. An attempt to survey the population numbers and distribution of seals on Lake Baikal with the aid of an airplane. Izvestiya Irkutskogo sel'sko- khozyaistvennogo instituta (Proceedings of the Irkutsk Agricultural Institute), issue 6, Irkutsk, 1954. 204,

UDC 599.74.5.2 V. M. Kogai

THE STATE OF THE STOCK AND THE PROGNOSIS OF THE FEASIBLE CATCH OF FUR SEALS ON ROBBEN ISLAND

The rational exploitation of the fur seal population requires the systematic study of the state of the stocks, on the basis of which an approach may be made to determining the feasible catch. With this aim regular counts are made of the different elements of the total stock. The specific characteristics of the animals and the features of the topography of Robben Island permit one to em- ploy various methods for evalua:ting the stocks and predicting the catch quotas. However only some of these find application in practice, those which are the simplest and which give sufficiently precise results. In particular, in the determina-

ee tion of the numbers of the genrations there is primarily applied the method of a direct head count of the newly born fur seals, which comprise the potential commercial stocks of the population. Furthermore, on the basis of the estimated size of the recruitment and of the mortality due to commercial exploitation, the size of the possible reserve stock may be obtained by calculation. In making the prognosis there are taken into account the yearly changes in the stock, including the the numbers of animals in the different generations, the natural mortality and the commercial exploitation, and then a basis is obtained for establishing the catch quotas. In other words, the . 205 ),

prognosis is based on the number of commercial.grade animals,

'j^emaining after the sealing operations of the preceding years,

and that recruitment which entered into the commercial stock.

Thus, the basis of the reserves of the commercial ani-

mais is made up of such elements of the dynamics of the popu-

lation as the recruitment, the natural mortality and the mor.-

tality due to commercial operations. A brief consideration

of these aspects is the aim of the present paper.

It is known that the commercial exploitation of the

fur seals has been carried out for a long time, whereas the

systematic accumulation of biological data on the fur seals

of Robben Island was begun only in 1957. In Table '1 are pre-

sented data on the numbers of the different generations of fur

seals, obtained from the annual estimates of the pups. 41 As can be seen, the numbers of the different generations of the fur seals fluctuate markedly from year to year.

These fluctuations depend mainly on the breeding conditions

and the biological peculiarities of the fur seals.

The absence of an increment in the birth rate in cer-

tain years calls attention to itself. From 1957 there was

noted â. growth in the numbers of the population, as a result

of which there occurred a progressive and constant increase

in the numbers of the successive generations. For the fur

seals it is accepted that the yearly increment of young stock

is equal to one third of the population (Dorofeev, 1964.). The

gradual growth in the numbers of the population permit one to

consider that the breeding conditions of the fur seals were

normal, which also determined the undeviating growth in the

206

Table 1. Results of the counts of the fur seal pups on Robben Island from 1957 to 1969.

T a 6 g a 1

PC3yab1'aTht rie.ra nplineoRa mopcmix 1OTIIK013 Ha onpoec Ttcoeilhem it 1957— 1069 rr.

ripliflOCT p0)1Z,V1eNtOC- MCTOR roe,' Konimew.lo roa on Years 1 li , % wipe:Le/ten itsi B. C. 1957 29700 — a YnTetio 1958 ' 32200 8,4 a prrelio 1959 35000 8,7 a plum 1960 38000 8,5 b Bb1,11tCJIC110 1961 41200 8,5 b menu:awl() 1962 44700 8,5 b Bb11111CjICHO 1963 49000 9,6 a ytiTeito . 1964 51400 4,9 a yrrello 1965 48300 a "pm» 1966 44900 — a ruelm 1967 56500 9,9 b uttInc.netto 1968 45800 . — a Puem • _ r ) • 1969 43500 a pueno

A. - Number of head - d) B. - Increment in bii-th rate, % C. - Method of determination a - counted b - calculated

size of the recruitment. The interrelation between the breeding conditions and the size of the generation is obvious. In 1965 the numbers of the new generation decreased noticeably in comparison with the preceeding generation, and accordingly no increment in the birth rate was found. An analysis of the factual data indicates that atmospheric and hydrological factors play a not unimportant role in creating the different breeding conditions, and that the value of the recruitment to a large extent depends on natural processes, which are never identical. 207

The employed methods for counting the numbers of the fur seal pups cannot be absolutely precise. - On the island the counts of the pups were generally carried out on August ' 1st, since carrying out the count at a later period does not guarantee its success. For this reason in 1960 - 1962 and in 1967 the determinations of the numbers.of offspring by the method of the direct head count was not carried out. It should be mentioned that in the conditions on Robben Island the counts were carried out equally successfully both with a relatively small as well as with a relatively large size of the genera- 127 tion. The configuration of the rookery and the simplicity of the method also permit such counts to be made under conditions of further growth of the population. Although the results of the count do not show with complete precision the true size of the generation, the method of the direct head count is reliable and simple in its application. This method allows one to obtain sufficiently accurate results, if, of course, absolute values are not implied. In some cases this is very important, about which more will be .said below. The calculation of the commercial prognosis depends not only on the size of the recruitment of the population but also, to a considerable degree, on the size of the losses. For example, in 1965 there was observed a large mortality of the pups (43.2%). This caused a lowering of the size of the catch of fur seals of this generation, which was represented in 1968 by the three-year old bachelors. In general it should be noted that the mortality of the pups fluctuated within wide limits (Table 2).

• 208

Table 2. The mortality of the fur seal pups on Robben Island from 1957 to 1969.

Ta6anua 2

• CmTnocTi, nennon mopcnnx KOTI1KO8 iia ocTpone Tionenbem B 1957 - 1969 ri'.

„ Illicaennom 1101.30- B • CMOrilltOCT6 upitpocT ritoe:ut, roiu, pommenn f0.1011 Years C roeou % rg

1957 29700 4888 16,4 1958 32200 MW« 10,6 - 5,8 1959 35000 5443 +5,5 + 4,9 1960 • 38000 3899 WM — 5,5 1961 41200 5899 14,0 + 4,0 1962 44700 6543 14,6 + 0,6 1963 49000 8237 16,8 + 2,2 1964 51400 9200 17,8 + 1,0 1965 48300 20902 43,2 +25,4 . 1966 44900 1493 3,0 —40,2 1967 56500 1354 2,4 — 0,6 1968 45800 8740 19,1 +16,7 1969 43500 4100 9,4 •— 9,7

A. - Number of newly born pups, head. B. - Mortality c - head D. - Mncrease in mortality, %

An analysis of the data on the mortality of the animals during the on-shore period of their life indicates that this depends to a large extent on external factors, such as, for example, the hydrological conditions and limitations of the territories. The mortality from accidental factors is insignificant. Therefore in the conditions on the island the study of the influence of the environment on the survival rate of the pups acquires primary significance. Let us turn again to Table 2. The data presented in this table indicate that, beginning from 1966, the mo.rtality was sharply reduced. 209

Considering this question in greater depth, it may be concluded that the measures, which were introduced in 1965, to extend the harem rookeries played a positive role with respect to the conservation of the young seals. In the fur seals, in comparison with other species of pinnipeds, the reproductive capacity is relatively high and this, apparently, to some degree compensates the relatively high natural mortality. In fact, the mortality of the fur seal pups in the course of the first 1.5 - 2 months attains a level of 14.0% on average (1957 - 1969), while in individual years this was as high as 43.2% (1965). Most of these pups die in the initial period of their life, when they still do not know how to swim and their organism has not yet become strong. Later, at an age of 2 - 3 months, the pups group themselves in the isolated pup rookeries and and are subjected to a considerably lesser degree to traumas during the fights of the harem buuls, the mass movement of the animals into the sea on hot days etc. The annual loss from the natural mortality is very closely connected with the formulation of the prognoses. For the proper orientation in determining the catch quotas of fur seals there is established the possible degree of exploitation of the different generations, taking into account the natural mortality. Thus, the 1965 generation was very weak as a result of the high natural mortality and the commercial yield from this generation was insignificant. In 1968 of the three-year old males, representing the 1965 generation, there were caught only 2.7% out of the total number 210 of this generation, while the average index over several years was equal to 8.3%. In the 1966 - 1969 generations there was a small natural mortality and therefore there may be. expected an increased commercial yield from these generations, in comparison with that of 1965.

The effect of the sealing operations is especially marked on the age structure of the commercial stock. The percentage ratio of males and females at birth is approximately equal, but with the attainment of the commercial age it is markedly disturbed, since only the males are taken for commercial purposes. To evaluate the commercial possibilities of the fur seal population it is necessary.to know the age composition over several years and also the degree of the commercial effect.

In order to carry on a stable and protracted commercial operation, it is necessary to limit this within the confines of the natural possibilities of the population. In practice, for

carrying on rational commercial operations it is extremely necessary to regulate the kill of each age group of males.

The 3-, 4- and 5-year old males make up the basis of the in-

dustry. The actual utilization by the industry of each generation, according to the age groups.of the bachelors (on the 129

basis of the 1969 data), comprises on averages 2.3% - two-

year olds, 8.2% - three-year olds, 3.8% - four-year olds and

1.4% - five-year olds. The total percentage taken.by the in-

dustry comprises 15.7%. According to the data of V. A. Arsen'ev (1968) this is equal to 18.0;?0. As is evident, the total kill

of males of all age groups decreased, even taking account of 211 the two-year old bachelors, which are not a commercial group.

During the last two years there has been noted a weak approach of the commercial animals to the island. This was also a cause of the decrease in the percentâge of the commercial utilization of the genrations. What the causes are of the absence of the commercial animals on the rookery is still unclear. On this basis, the prognosis for the fur seal kill for 1970 should be not at the maximal level of the commercial yield but at a lower level, comprising 15.7ô.

CONCLUSIONS

In the evaluation of the fur seal reserves there are considered and analyzed the factors which influence the population numbers of the s,nimals -during the on-land period of their life. It does not yet seem to be possible to take into account the intensity of the approach of the animals to the island in different years. In connection with this, errors are possible in the-quantitative evaluation of the fur seal catch.

The proper management of the fur seal industry and the extension of studies on the biology of the fur seals will permit the most rational utilization of the reserves of these very valuable commercial animals. 212

REFERENCES

JII4TEPKTy Pn nponthlCnonoro Ilcno:11 30811111A noxo- !I(ICCH6e8 B. A. Meroullxa onpe,zeaclutn -I3DecTiln THHPO , T. 62, 1968. IICnI111 lüOpCKn\ fi0TII1:OD. TpyALl I3I-II'IPO. T. 68. I , T. 54 ; Tpyqbl 1(0ÿ0j1CC6 C. B. CeBepIIhIC 1,tOpCK11C KOTlilin. I43BeCTIiA TIII-IPO IIHI'iPO, T. 51,196-1.

1. Arsen^ev V. A. Methods of determining the commercial exploitation of the generations.of the fur seal.

Trudy VNIRO (Transactions of the All-Union Research

Institute of Marine Fisheries and Oceanography), vol. 60.

Izvestiya TINRO (Proceedings of the Pacific Ocean

Research Institute of Fisheries and Oceanography), vol. 62, 1968. 2. Dorofeev S. V. The northern fur séals. Izvestiya TINRO,

vol- 54•. Trudy VNIRO, vol. 51.* 1964. 2 13

UDC 5 99 . 74.5 . 2 A. V. Zasosov

A METHOD FOR DETERMINING THE SIZE OF THE FUR SEAL 130 POPULATION AND OF THE MAXIMAL POSSIBLE STABLE CATCH QUOTA

The fur seal populations, which were almost exterminated at the beginning of this century, fairly quickly reestablished themselves after the quadrilateral agreement on their conservation came into force. The "ceiling", which was reached towards the middle of the century by the steadily increasing numbers of the fur seal, began to be subjected to considerable fluctuations. With the aim of elucidating the patterns of the change in numbers there was constructed a simple mathematical model of the population by the American investigator D. Chapman, which permits quantitative determinations to be made of the commercial reserves of the fur seal, by calculating the number of individuals, and allows one to find the value of the MSY, the stable maximal possible quota for the take of this valuable marine animal. It is impossible to show the essence of the of the operations carried out without some very brief information on the biology of the fur seals, the sexually mature males of which, as is known, are polygamous. From the point of view of the most complete characterization of the existing population of the fur seal, the entire aggregate of individuals that comprise this may be divided into six groups and distinguished in accordance with the indicated scheme (Figure 1): 214

Population

Harem 1 Bulls J IFemales] r Bachelors [Yearlings I =Pups bulls without harems

Figure 1. The structure of the fur seal population.

1) harem bulls - mature males, which maintain harems over some part or all of the reproductive season, i.e. from the end of June to the beginning of August; 2) bulls without harems - adult males which do not maintain harems. In addition to the adult males which do not maintain harems by reasons of weakness or senility, there also exist males which find themselves without a harem for only a part of the reproductive season. It is fairly difficult to draw a line between these two categories of haremless males; 3) females two-years of age and older, which mate for the first time at an age of three or four years and which give birth to one pup in the middle of the following summeri; 4) bachelors - sexually immature males aged from 2 to 5 years; 5) yearling fur seals of both sexes; 6) pups, the suckling period of which lasts for 4 - 5 weeks, after which for the remaining part of their first year of life occurs their familiarization with the ocean.

* In some exceptionally rare cases female fur seals begin to mate at an age of two years, as a result of which a very small number of these begin reproducing at three years of age. The age of 4 years in females is and is acknowledged as the first year of normal reproduction. 215

The pups, which are mainly born at the end of June and during July, collect together in large, almost homogeneous groups at the beginning of August. During this period they are relatively immobile and their various groupings scarcely mix at all. The pups live on shore until November, at the beginning of which, changing over to a marine way of life, they leave the dry land. It should be noted that the displayed above-mentioned features of a fluctuation in the population numbers and of a retardation in the rate of growth of the commercial population have given rise to several hypotheses which explain these circumstances. Initially there were taken into consideration only the effects of external factors, i.e. mainly the climatic and oceanological conditions. Then, somewhat later, there appeared hypotheses which admitted the possibility of the existence of a dependence of the numbers of the population on its density. And, finally, relatively recently, based on observations there were found cases of an extremely sharp drop in the yield of the bachelors, which gave rise to attempts to explain and to formulate in mathematical terms the relationship between the numbers in the pup generation and the number of fur seals surviving to an age of three years. Attempts could be made to explain the decrease in the yield by the increase in the on-shore mortality of the pups, but the latter is responsible for a very small portion of the total loss which occurs over the first three years of life of the generation of fur seals. Besides the infestation with parasitic organisms, there exist many other factors of this sort, determining the on-shore mortality of the fur seals, 216 and at times it is completely impossible to establish the cause of death just as it is impossible to establish whether the infestation causes an increase in the mortality of the fur seals at sea. At the saine time, as the observations show, the mortality of the pups on land from parasitic organisms and other causes of a natural character drops rapidly already in the middle of August, although the pups do not leave the island until the end of October. An increase in the number of the fur seal population 132 may undoubtedly lead to an increase in the population of predators. As observations indicate, some of the latter always and distincly strive to have a closer contact with the weakest and most helpless individuals of the 'population, the pups and yearlings. Unfortunately, very little is known about the essence of these interrelationships. In clarification and explanation of the essence of the relationships between the changes in the size of the yield of the three-year old fur seals and their numbers at birth, most obvious is the fact that,with the growth of the fur seal population in the regions of the Bering Sea adjacent to the islands on which occur the whelping and fattening of the young, with the passage of time there also occurs an exhaustion of the feeding grounds. This circumstance may turn out to be very appreciable in the fattening of the pups. As the food organisms are consumed in the waters directly adjacent to the sections of shore, on which the rookeries are located, the females are forced to undertake longer and longer expeditions in search of food. Having destroyed the food reserves, the females, 217 which are feeding their pups, expend more and more energy in their search for food and for locomotion, and expend less and less of this for the production of the milk. In connection with this, one of the critical periods in the life of the fur seal, the transition from the life on land to the life in the sea, may turn out to be fatal to the seal. The success of the transition may depend on the thickness of that layer of fat in the pup, which it succeeded in acquiring during the course of the summer fattening. For the purpose of representing the quantitative dependence of the survival of the pups on the food supply, it may be assumed that: 1) in maintaining its existence, a nursing female consumes b units of food per unit time; 2) the nursing female spends a part of its time, on land, while for another part of its time, vr, it is moving in the sea, in search of food, moving away from the rookery to the distance r; 3) the degree of food consumption by the nursing female is characterized by that quantity of food units,f, which it is able to eat in unit time. On this basis it may also be assumed that the net gain in weight of the nursing pup per unit time will be proportional to (1 vr - rt) f - b the coefficient, depending on the quantity of food which is expended by the nursing female for the production of milk. It may then be concluded that the total reserves of food that 218 are necessary for maintaining the population of nursing females and of the pups nursed by these females should be proportional to the number of pups E. Such reserves of food should be located around the rookery (island) in an area xr200E. From this it follows that the radius of the circle which determines the size of the area, in which the fur seal females with new- 133 born young are compeled to feed, is proportional to g = e the square root of the number of new born fur seals * (e- constant of proportionality). The quantity of food consumed by the females which goes into the production of milk for the pups is determined by the summation of this in the area of the feeding grounds, i.e. by the Integral

j • )f-b] dr, the calculation of which reduces to the form Av-E - BE, in which vfe 2 A= ■e (f -f-C-b); 2 • If now one assumes that the survival s = — of the pups is

probably proportional, s = k(A -e - BE), to the quantity of food consumed during the summer (during the nursing season), then the average number of surviving individuals of the fur seals will be represented by the relation N= k(ATE-BE)E, or N = -y pE2 , (1) in which r4: and p are parameters, dependent on A, B and k.

* The conclusion is unchanged if it is considered that the area in which the food organisms are located is not a circle but a sector. 219

It should be noted that for the determination of precise and

specific numerical values for the Parameters f, v, b and e it is necessary to have thorough biological studies, organized in a particular fashion. However for a first approximation, adequate for the formulation of practical judgements, the values of the parameters « and p may be calculated on the basis of observations on the results of the breeding, of the sealing operations and of tagging experiments. These types of observations and experiments have permitted the recording of the relationships, shown in Table 1, between the numbers E of some of the generations of pups and the numbers Nm of fur seal males of these generations which survived to an age of 3-years. The use of the relations obtained and the treatment of the tabled data by the method of least squares gives rise to the equation

Nm = 0.02314 E - 0.0008E2 .

Table 1. • Survival indices of male fur seals of the Pribilof Islands. Ta6znita 1 EloKa3aTeau nbuimsalutsi caninon Kant Kon ocTpoBoB flpa6m,rioBa

A linceennocn noroeoubn 411C.IctillOCTI. 110r0.710111.11 KOTII- n01:0,1ettite nienaou, roeon ROB camnoa 3-aerncro noapa- Generation Cl-a. ro.11011 •

' 1920 143000 23190 1921 150000 22241 1922 159000 24523 1947 480000 60949 1948 514000 55990 1949 525000 47876 1951 59844 1952 514000 69395 1953 685000 49839 1954 722000 33128 1955 744000 40409

A - Numbers of pups, head B - Numbers of 3-year old fur seal males, head 220

x 40 N,,, z. 023^E 311?-. 00Lj8E 2 . ^,... ^

//,,7 =. 223E --. 00023E 2

?a f ' L._ L s 1 1 z 0 /00 200 300 400 500 600 700 T qL.1C.?c.°HHOî/TIb L.CyrEfNKL•l Ü, /77NC' 2017O9 Numbers of pups, thousand head

Ÿitc. 2. I((1nL`i.1e, K8[lai:TePII3y10111tie CoOTIlO11ICnIle llncsennoCTii nOKO7eIti[Ît tijelr KOB (E) Il 4IIGICIIHOCT11 KOTIIKOB CFl\IIjOB 3T1i5 nOKO.-Ielitl}{ (N), R0)KIIBBiOn[IIS i p•0 3-:ICTIIeCO B03PRCTa

Figure 2. Curve's characterizing the relationship between the numbers of pups in different generations (E) and the numbers of male fur seals of these generations (N) which survived to an age of 3-years.

The results of the calculations made are shown graphi-

cally in Figure 2, in which the curve drawn by the dot-and-dash

line is a representation of the equation referred to. As to the second curve that is drawn in this figure, 135

it corresponds to the equation of the parabola obtained on

the basis of those considerations which were utilized by M.

Shefer (1954•) in constructing a model of an animal population,

having the form

Nm = kEy (E).

The function (p(E) in this case is that simplest linear function

which takes into account the density dependence of the change 221

in the numbers of the population and which gives to thi5 the form Nm = AE - BE2 . (2) The results of the estimate of parameters A and B by the method of least squares give rise to the equation • Nm = 0.223E - 0.00023E 2 , accordingly depicted in the figure by the continuous line. It is interesting to note the fact that the curves obtained are in fairly good agreement with one another and indicate that the maximal number of male fur seals, surviving to an age of three years, are ensured by a generation of pups that numbers 14.80000 head. The latter circumstance permits one to make judgements, with a greater.or lesser degree of confidence, about the maximal possible number of male fur seals which may be removed in a stable manner (i.e. annually) by the sealing operations from the composition of the population. Just as it is impossible to state a priori that there are no reasons which should serve as a basis for limiting the kill of the males, so also it is impossible a priori to assert that the survival rate of the females should be the same as that of the males. Therefore, with Nf designating the numbers of females surviving to an age of three years, it may be written that Nf = . (3) This type of assumption may, of course, turn out to be a gross simplification, since the ratio of the number of males to females may, undoubtedly, prove to be variable, both with a change in age as well as with a change in the population density, i.e. with a change in the numbers of the population.

222

Let it be assumed also that the average pregnancy index P and also the mean annual loss* of the three-year old females are the same as in females of older age groups. From the latter supposition it follows that E pups may be produced only by p females, of which a portioncpf dies during the course of the year. We will designate by H the number of males of the parental population which die during the course of the year from natural causes. Then, taking into account the obvious circumstance *, that the total annual loss of the population from the sealing operations and natural causes, with a stable state of the commercial population, is numerically equal to the size of the age group which is first subjected to the action of commercial operations **, it may be written that

Nm + = Y + H E.

The size of the balanced catch quota of fur seals Y is determined as ff y = - H E •

Consequently, if the survival of the male fur seals is characterized by equation (1) and if equation (3) is also taken into consideration, the size of the balanced catch quota Y is determined by the term

y = 1.(1+X)e- e-e-f-E-p(1+x)E2 - H,

there is introduced the designation h - , by or, if p(1+ A) the term Œtpe I TI PtPfE2 E-4' E - H. (4) Y hP hP

* One of the first scientists to show this was the Russian investigator K. K. Tereshchenko. ** In the fur seal population - the third age group.' 223

Elemèntary calculations show that the sealing operations may

constantly take the maximal number of head of the fur seal

MSY (i.e. Ymax.) only in that case when the numbers of pups

born in the yearly generations will be

E^ = C -r 4g^28P - ^2f^11^ 2

It should be noted that function (1) is maximal with

E = .^ i.e. with E> E*. (0)2 If however equation (2) is made use of for character-

izing the survival of the males, then it indicates that the

maximal number of head of fur seals, which the sealing opera- 13?

tions may constantly take, will be'ensured with the number of

pups born in the generations being equal to

E** _ A. - h é 2B

i.e. again with E>-E**• In other words, both equations indicate that the num-

bers of pups which would ensure the maximum productivity of

1 thé fur seal population would be lower in the case when the

sealing operations would utilize individuals of.both sexes,

and not only individuals of one sex - the males.

In order to form a judgement about the estimates of

the numbers of pups in the genrations, E* and E**, it is first

necessary to calculate h, i.e. it is necessary to obtain esti-

mates of the valuescpf, p and X. To estimate the pregnancy

index p and the annual loss of females j^,f one may make use of

the results of a specially organized (experimental) kill of

these, as was made in 1958 - 1960. The calculations which 224.

were made, utilizing the results of this kill, showed that o the estimate of the annual loss of females was fairly close to the valuetp f = 0.20, while the pregnancy index of the females was close to p = 0.6. It is much more difficult to obtain an estimate of the ratio kof males to females. Un- fortunately, it has not been possible • o obtain direct information which would allow us to establish the precise pattern of their survival, and therefore the estimations (NSY) were carried out for three probable values of ?t. (À= 1.5; X=2.0 and A.= 2.5). It should be noted that initially .4=2.0 was assumed to be closest to the real value. However later observations, carried out by Japanese investigators, showed that this value of À was too high and that a better estimate would be = 1.4 .

REFERENCES

• JIHTEPATYPA • Tto- 1 Bbtlacoo B. A. Ha6mo.aenna an CaNIKaN111 rqopckoro koriwa na oc-rpoae jieiueI. Haaecrnst THHPO, T. 54; Tpy,abt B1-11:1P0, T. 51, M., 1964. juin 2 Bblqh:00 B. A., ,4opm4eee C. B. BuoaorntlecKne npe.anoemokn perfflp0- 13811M1 Cen ,lert Ha °mom: Tamenbem. HaseeTua THHPO, T. 54; Teel 13I-I11130, T. 51, M., 1964. MyetatuKun B. 0. Conpemeintoe COCTOSIIII1C Ypnabero KOTIIROBOM menc6nuut iia OCTp0I3C Me11,110M. H313eCT1131 THHPO, T. 54; Tpy,abi BI-111P0, T. 51, M., 1964. U. Bartholontene George A. Mother — young relations and the maturation cif pup behaviour in the Alaska fur seal. «Animal Behaviour», 7, no 3-4. 1959. 5 Keityitz Karl W. Territorial behaviour and homing, in the Alaska fur seal «Matnmalia», 24, no 3. 1960.

1. Bychkov V. A. Observations on females of the fur seal on Robben Island. Izvestiya TINRO (Proceedings of the Pacific Ocean Research Institute of Fisheries and Ocean- ography), vol. 54; Trudy VNIRO (Transactions of the All-Union Research Institute of Marine Fis4eries and Oceanography), vol. 51, Moscow, 1964. 225

2. Bychkov V. A. and Dorofeev S. V. Biological premises

for the regulation of the numbers of harem bulls on

Robben Island. Izvestiya TINRO, vol. 54; Trudy

VNIRO, vol. 51, Moscow, 1964.

3. Nluzhchinkin V. F. The present state of the Uril' fur

seal rookery on Mednyy Island. Izvestiya TINRO, vol.

54; Trudy VNIRO, vol. 51, Moscow, 1964. 226

UDC 599.745.2 V. A. Arsen'ev

THE LOCAL DISTRIBUTION OF FUR SEALS IN THE SEA OF JAPAN

The question of a distinct distribution of sex and age groups of fur seals in the sea in their wintering grounds is of important practical significance. The many years of experience of catching fur seals for research purposes, conducted by the four countries that are participants in the Temporary Convention on the conservation of the fur seals of the northern part of the Pacific Ocean, in the eastern and western parts of the North Pacific, have shown that there is a predominance of females of different ages among the animals caught, and moreover most of the sexually mature females are found to be pregnant. The ratio of males to females in the catches is not uniform; occasionally males even predominate, though such cases are rare. In Tables 1 - • is shown the sex composition of the fur seals, caught for research purposes by the Soviet Union, Japan, the United States of America and Canada during 1958 - 1961 and 1964 - 1966. These data may serve as one of the arguments in resolving the question concerning the prohibition of pelagic sealing (which was envisaged by the Convention), during which there are destroyed not only large numbers of breeding females in general but also many pregnant females. There exists the opinion that distinct age and sex groups of fur seals form, to some extent or other, local 227

concentrations. In the opinion of some Japanese investigators, it is possible, with some practice, to identify the age groups and sex of fur seals, encountered in the sea, with a high degree of reliability even at a distance, by the colour of the moustachial whiskers and the general appearance. It is proposed that it is possible to carry out at sea just as selective sealing operations, as on land, catching only those groups of fur seals, the removal of which would not cause detriment to the population numbers. Hence the question may be set concerning the possibility of a selective commercial catch of fur seals at sea. In the present study an analysis is made of the fur seals caught for research purposes by the Soviet Union in the Sea of Japan, numbering 1825 head, during the period from 1958 to 1968. The materials were collected by a large group of workers of the TINRO. Most of the material was collected in April, somewhat less - in March, and still less - in May. Data for the other months are are extremely small. The caught fur seals were divided into prearranged age groups. The youngest males and females (yearlings and two-year old animals), of which very few were caught, were included in one group and on the maps they are indicated by one conventional sign. The remaining males were divided into two groups. In the first of these were included the sexually immature bachelors (3 - 5 years) and the half-bulls (6 years). In the second were included the sexually mature males (bulls) of all ages. The females were divided into three conventional groups. In the first were • •

228

a Cs1 GO. C) t-- t••••. OD 01 u, (di CD •-••• css ts-• C4 1 Ce t•-• • - CO ••4• C•1 6ax Ta t- 0-) to cf: co co 00 78 c co CD Os CD 1 1 •-• C••1 `sr g O•1 ••-•

0 0 o •-+ CO. 01 co co cs) 0.1 C'.' CI el. N: o - «5. co cd ,-;" c)c._6 c6 0 16 Li-, 0) oo CO CO • CC) ,e c,. lo c-,1 r-.. cl) co c,) ( 0 -I-)tO _____ — ______Q) - e • 0 . 0 an CD •-•• c:› 00 to 00 10 ••ce 00 0) f.' 1 g N. CO •,..., c,., V- crà ._. - 0 C.) o ..... . ... t- .... ,..C`I CO 10 • -er OS co •-• t--- 4 e Oce e 0 .,... . q. c, •r-I •r-I

O. ic CO "e i s - al cl. t---. r•-. 00. ez, oi- 11 CO Cs cry OD CO t.0 Cs1 C-••• m c•D .. if ____ .—... 4-P P o c.. i 40 -P

.1) Pac . r4 0 cc U) cd (--_, «j .r4 6.) U) In 0 0 L.

c i -. cD uo c'S :)) I I t— 0 c,.

t — —

g a 0 o e E-I — .. v) s••• • , U) CO CO 0 0 — a oic nr et t— El Cst t- H co •1 se xu G-)``) I I cr)''' • 1 c)'n 1 Lo)e 1 1 c(c'e)")`''''.) - az, '-' - co cd 4 0 DI Tu I. U) e{ — 5 , $.4 el l 11 H 0 g Il

>i 0 •H 0 • 0 cr.] 11 11 11 11 11 11 , ea ter a o . •C-1 X - f. • -P 1 1 1 1 1 1 1 / 1 1 1 1 -P 0 e 5 0 I I I I I I 1 1 1 1 1 0 O a) ci 0 7 0 0 I I I I I I I I I I l cf-i cC (/) 0

• r.r. 5 A ›. '.. r': . e '2 ,7•5. 7,-: A r-I G G (0 (0 CO CO CO CO (0 (0 CIO CO (/) • (.) 00 00 00 0 0 00 cd ta a) rii . .'. rt-1 r4 139 rCi a) r=4

• - • ..eance-ceee-e. 229

(w M C^ ,. V^`. f0 i^ ID sY -^ ^ c^^! Cr) c t i in. tr M :D

lf^ [r l^. ti . cx^ N N .-• LV I^

a> h: M C-- tfl ^? CD -e oc; Co CD -: Co pcM cÔ ' cV ^ r ^4 c p 1' Cq^ ^

aD 10 --^ IC^, lf^ tp O ^.cV. M;tn t^ te.

O -+ ^ ^ ^:-, oc, ^n. ^ D V ^ InC^ .n Gq h c0 v? Le? t0 tD C7 tD [:> O c^ Qi C) M t` Q CD' • ^M iL'^ rn ^ c^ rn rn ^ ^ L7 C d h ^ ^ .^ .... ^. G^^t i^ ^^

^ M U, Co N ^ CII tD O M Lrj •--•

tp tt] CO -. 4 O cQ cp ..,wc o: ôô in v`t7

^ ^ f w rn IP N M

M M r,+ Mt- CI, Co CO Co M tJ clJ CD

N e ..- C-j

C r ro [y ^ Cu c3 c0 Û Û U U U U U Ù V U Û U .^...+^.+w .^ .T.:.. -....:T'... . , ^.f.:^... .^.<.iuWe'rn_r.-. u:>:sy _•F'e'f'...r^lJ'_^é::.a...v..r^M.t.n::'^.ua-.w.. 230

Ta6nHUa 2 ► 0 ' q 0Ji0B01! COCT2B }:OTIIKO[S, ROÛLITGIX 11 3afiaml01t 41CTH Cenep:lolï 11aqH(j)HKH S1HOHHei3

. I J. JL -L Y: L)vUs^ 4>eBpa.1^ `lapr t+pcat Aia+ 1710t1b

Iloa ):oni+- icoal+- I sonu- honH- noan- Sex ^lE'Cl'DO 4CCTDD '0 90CTBD RBCTBO 'O 4Cl'TBO rin_ I I nn. no . 1 nO. I no.

1958

yM CaDfl[bI 70 53,8 186 60,2 553 44,7 495 45,1 69 39,9 F Canu;H 60 46,2 123 39.8 685 55,3 602 54,9 104 60,1

1959

M CantuLl 85 44,5 242 40,0 655 43,8 173 36,7 14 25,0 F CanlxH 106 55,5 363 60,0 I` 840 56,2 298 63,3 342 75,0

1960 M Cantqltl 26 52,0 264 35,8 184 35,7 35 41,2 ao N F çanH

1961 M t 1i Ô r m^ M Camuut 15 26,8 254 39,1 230 30,9 23 60,5 F Cann

1964

M Ci+niljLl -- - 104 31,5 6 46,9 175 33,: 5 6.0 oc^ F Cantuli - ^ - 226 68,5 211 53,1 353 66,9 78 94,0 17ô ^ ` r^ 1965 to C) C14 CO M Canlubl 52 29.2 76 1 53. 1 156 33,9 94. 26, " 3 F Canit:ll. I 126 70,8 65 ; 46,9 1-.301 66,1 264 . 73,7 "?I h

C+J Cr1 1966 N.' Caritu6l 20,8 54 26,5 ' 70 24,7' 13 15,5 - F CanlsH. ^. f . 79,2 150 73,5 213 .753 71 84,5 ' Bcero TOta1

Ni Cantuhl 155 48,3 655 39,2 2042 42,0 1483 37,1 253 28,8 F Ca',IxH' 166 '5i,7 1017 60,8 2819 58,0 2512 62,9 62-1 71,2

141. Table 2. Sex composition of fur seals, caught in the western part of the North Pacifie by Japan

Ni - males F - females •

231

cg . 0-1 00 0i CD — 03 II II II II -- CO - 11

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LO • • •ir.P

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f CO 1 1 1 I ■••■•■•••■••••

, . c -,... t o --. c) oo In cv -- I ' I 1 c ••,•• Q Q 1 co c',1 1 i ._. 1 co I 1 --i —01 ___ — --- _ ____. •■••■••••• — 0.0. -. CD CI CO. par CO CD CO. CN. CD CD s 0---. to to 1 1 z ms. --. op 1 1 1 . . 0) x --- --- •e• ------______c..1 ,..›1 co co a) 0 o • — co •,••• :0 I I 0, I 1 , --1 i....' --- cc fm;) 0., ._. I I ,.. c-._. cd • FO> CD = — - -P • Cd C1. 00_ CD..-- 0 ,i• in 0-1--. z , (0 c."0, CO CD' CD CD • C) 10. I I c (•,s . 1 1 0 11 0 o -..-1 — co c . c...

-- ,.m -- —, — -.ct.. — In Co_ op -P0 c..) • -a- to 1 i co C".1 cn - le) 1*--. cy, IC i . c.c. 1".• CD CD 0 1 1 --. -- Cre -- Cr) Ln 7-•:. .._. 0 i. _ ii() 0 c'D CD I l CD o0 •ci. OD I I c.) — • •-• ••••-' .-. •""' _....— _—_, • -z --. •-• ••••• ---- ce... D . CO CV 00 Cs1 0. •-• i q. C).. • 4-t .....t•-. ni. ••••• C73 00 --. cCi Ci • '... GO ..") n'r r.- C•1 — (0 I I -P 0 2< GS C" t•-:- CD Ili ..1.• CI t.:- . — — .---. ------.--- r-- -•••• CO 40 tn à- cu 10 .. .0 0) •-•-• 10 to o I- 0 • I,- c•D c.0 up CD CD ( CD ..-..-. el I's 0 C0 0'3 04 t-•-• Cg ‘‘J "0' CV ..... ..... •-•.. C`.1 0 ,d .z,• . (tS -P gn t- .It3 0 .01 1 I g o cc! c) a In In ee..`e. — -P x .. ..1. r-2 CD C0 c... t--- - .'CI) e--:.(1.. tr.-:.e" i I I I crà

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'••• 2 32 •

co (0 It d's) rct a ',:_,5•V'D 11 • 11 - -11 II ro:t, r.1 g • 19 0 Co 1.1 it 11 11 si• CO H a C; -P C11 ;-4 10 CO ■ cci C). t I to. uo CS), p y cc r•I ce; CO •-■ CO 00 to" pt I • 1 '1Go CC LI 11 xcn• 06..; • N. _.., CV co I I tO il P•I CO •=-.!! • I I HbI tû PI LOGo HCi; CI C? GO CD 10 L``. cD„c) (13 CO'

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m• • _••••• m • C 14 0. eD re. cacti cue me rio cor.: 0 c.3 0 • 0 CO ro UV UL.) 00 00 UU 00 00 00

144

reratta--- " 233 included the sexually immature animals 3 - 4 years in age (in the year that they are caught in the sea the four-year old females mate en masse for the first time). In the second group were included the young sexually mature females 5 - 7 143 years of age. The third group consisted of adult, mainly multiparous females 8 years of age and older. - On the maps located below, for each of the three months the males and females (excluding the yearlings and two-year old animals) are indicated separately and flim each of the conventional groups was assigned its own designation. The region of the catch of each age group was arbitrarily outlined. The numben3of animals of the different groups in the catch were not uniform, which makes it difficult to attempt to compare the data according to the different groups. Most 145 numerous was the group of old females; the group of yearlings and two-year old animals was the least numerous. March (Figures 1 and 2). Concentrations of fur seals in the Sea of Japan were found close to the continental coasts, including the open part of Bay of Korea, and in the central part of the Sea, where the Yamato grand banks are located. Fur seals of all age groups were caught, although there were very few yearlings and two-year old animals. Among the males there was a predominance of young animals 3 - 6 years in age. Among the females, in contrast, there was a considerable predominance of old sexually mature animals; there were fewer sexually mature young females, and very few sexually immature females. The regions of the finding of the different sex and age groups overlap.

234

12e 1?9 ' 130° ill' 132' Ir 134' 135° 136 37 135 Ife 42' . . , . 30' :1 • 47' • MAP 1 • 42

RAPTÎÇ . • ', ,MA.Pr Agè

i March - e-- d'9 1•2 41' ••-, - . *•••••\, 1 --- d .... i , •,,.. ...... --- d ' ,..-1• * t I It.e., , 4 , •• ,, ci) f • •-... e .e-t 43 Le. • . \ q;--e) .. .,..i , . 39' \144.4 eo )..:// ...

• • u. 4' . A'

. •C7 e.

_ • 3t 37° 12+ 1 9' 130' 131' 132' 133' 134' 135' 136' r31' le' 7:••:. t4o.

Pne. 1. PacripeRe.nenne eamuoa KOTI1KOB B mapTe - • Figure 1. Distribution of male fur seals in March

• Thus, in March the males and females of all age groaps are distributed in the same regions of the Sea of Japan and no distinct distribution of these is revealed. A p r 1 1 (Figures 3 and 4). In comparison with March, a larger number of fur seals were caught and the predominance of the females was more marked. A part of the fur seals had moved to the north and the region of findings had become more extensive. Young males (3 - 6 years) predominated numerically over the older males, they were found throughout the whole region of the catch and in some places they formed accumulations. There were few yearlings and two-year old animals (males and females), they were caught together with the ani- 148 mals of older age groups. Among the females there was a marked predominance of the older age groups, while the sexually immature females (3 - 4 years) comprised the smallest

128° 1:5' 20° 131° 137° 133' 13/,* 135' 136" 137° 138° 139° 42 , 110' g ge fe MAP 2 • - 42' , KAPTA 2 Age MAPT impel' re . March ,,,,--•- .9 3-4 41' 41' •:," , +--- 9 5-7 • . .:. "" ...-- . ---- 9 8-10' 1

_ I:, ig4 110 .,....1

D --/-«- 3 -.• •

38 ' • • 4. . , :' 0

1' .,. l'. 31' ? 128' 159' 2.G° 131' 137° 133' 24' 135 nr ir. 23' _ .. 139' NV

Pac. 2. PacnpeReaellne camoic KOTHKOB B mapTe Figure 2. Distribution of female fur *seals in March

12E' 129' ;30' 131" 132' 133' 134° 135' i3 6 137° 138' 139' - 40' 42 pm 4., 30' ' :•':»7---.7 'ti 30' '...'i- ---- . 'e,:■ ' le MAP 3 42° ‘,.... , KAPT'A 3 ,Arnserp. , .• I •-. \ • - April ,..--,. _Age • . 150 ACT 41° • ".,,•:... -71-. ,,,,,,.-;.--- .1 • 41° • • 4,:„....• ..:.,— ce•c? 42 ). • • ..• . -- — . ..• N.', • l' r cr 7-1o* *--- 1.. '4'. '.. ,.«--.3.;\ . ps — .-----c-.--45.s...1 (3"I 1 __ ..._ _ - - -,.., • '4__-. 1 i ed 40 ° ../ • „ /.. •, / et.' N ,...'-'•-..t.)' tt; - tz., . .--,..."` :Ii•••:• * 0 ,/ . N. ... 39

• . . . .:::'..

' .:.:. . \ • 33° •':.\ . • ...... . • - .:;'•:' e it . ..: 37° , Ite :',‘ 7:• isr 132' • 133' 134' ' 135' 136" 137' 13 " 139' 140

Pac. 3. PacripeAeacane camgon KOTI1KOB B anpeae Figure 3. Distribution of male fur seals in April 2.36

MA.P LI' KAPTA 4 nnPeJlb.,G, Apri.l 6'J]PACT v _._Q 3-4 1 41-

31• i^' I 134 ^7i• '^s• b3 13c ht 1?9• 130 111 jr, 137 p 1-11c, .1. acnpcuenettne cae(oK xoTnxon B Distribution of femal.e fur seals in April Figure 4.

lAJ' 141• 14: 131' 1^8' If9• 133°^ 13 E. ID4' l3p• 13P I^.' '---^^ •T)

I pnc. 5. Pacnpettenenne cantuou xoTnxon B Mae Distribution of male fur seals in May to* Figure 5.

237 t. •

Ile ' 137. 133* we iss• CV 13r us• ID' ice 141' 142'

45. '•:.45' MAP 6 ... .1( APTA 6 mAil W May :. . ... ., , ' 0,....rx 43" ' • e.> Age - 43' • 1503PACT -*•:.•:::::•:•'; :'• '-`-- ? 3-4 . , r -:- . +... 9 57 42 - . ••.«... o

4r 41'

: • t': 0° 130' le 132' 133' .134" 135' • 13G• 131" 13S. • ' 133 ° 140' 141" 141'

Pile. 6. PaciipeAenoillie camoN KOTIMOB .mae Figure 6. Distribution of female fur seals in May

group. On the Yamato banks the females markedly predominated over the males, while in the waters adjacent to the continental coast such a predominance was scarcely evident. The males extended further to the north than did the females. In April distinct concentrations, differentiated as to sex and age, were also not found. M a y (Figures 5 and 6). There is noted a displacement of the fur seals of all age groups in a northward direction, though some of these are still found in the regions where they were distributed in the preceding month. The yearlings and two-year old animals were represented in all by four specimens, these were caught together with animals of other age groups. Males and females occurred in about equal numbers. The number of young males was more than twice as great as the number of sexually mature males. Among the

r■-■-•■•■•••••■■■•■■■■....

238 fi

l3• 1:: 131' 131' 1W 85" I - 13"/" 01V t5' 3/

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4 .1 fl. 21 8 31 • 402_....21 ... ,t 42 • ‘ 0. • A00M2OP8111 i cr. 9 ferit‘'nfKr.FT:;•Wey 29.e.1ot BO3P4C1 0.04 f10374Ct fin • (3 9.44'''13e'ee°•A Il 3' 1 4 1 tReei.b14 XPRI • 40 4 r 5 0 7 1 7 604. 603PAtT 1.8,51 10* 1 8 21 03 ,.vi, •Î § V, 1 ..£0.2_1* tlinnbf■ •Apiti.t. II 1. ili 1 e.e. .9' • s., r io .e00PAH,AT ,1: 40 54..7 41.81.0 OA 00024r.i'l1001.b03P4aebra mle-130.25rle. io -77e 4 3, s I etsoPrieinbr..39•$8. - 40•05•c.w. d 5 5 18 f 10V 01-134'10' 8.8 6 f 10. 4 2 7 2 --- -ir 8 0 • '----'1-r. i 3r ROOP/111143b1:.35 .47 . - 4-004' 8110,. 1 33•49' -13 4 0 eb.A. e .

---cep-..=aseabor ,-,-...., — -----....,..-.er 20• 11, ' :ia• Ili' O..' 133' DI. 155. W IW W W We\

Floaouoii 11 1103pacTliOtt COCT1.111 1OTI1KO13 , p,o6LIThIX. II Tenemie 0./1,110ro

Figure 7. The sex and age composition of fur seals, caught during the course of a single day. a - age b --number - coordinates d - lat. N. e - long. E.

females, as previously, there was a predominance of animals of the older age groups, although their concentrations were somewhat smaller than in April. There were very few young females. In May the animals of ali age and sex groups were again caught in the same regions. The preliminary conclusion is that in March, April and May in the Sea of Japan the fur seals do not form concentrations of different ages and different sexes, and we still cannot establish regions of aggregation of the different groups. However this question is fairly complex and requires additional studies. The generalization of the materials by months does not permit one to reveal the details of the distribution of the fur seals in time. We attempted to establish separate aggregations of different ages by the composition of the daily catch of fur seals. As an example there were randomly selected four days in April of 1965, with a relative-,* ly high catch (Figure 7).

As is evident from Figure 7, in all cases in the catch there were represented both sexes of the animals, with the females always predominating over the males. The males were represented by animals of various ages. In two cases out of the four there were caught only sexually mature females of different ages, while in the.other two cases together with the old fernales there were caught young fomûles. In not a single case was there founda marked predominance of any one' age group. The oldest females (10+ years) comprise an exception to this; however, firstly, this group always predomi- nates in the catch and, secondly, a large number of ages are included in it.

CONCLUSIONS 150

A preliminary analysis of the materials indicates that in the Sea of Japan the fur seals form mixed aggregates, in which there may simultaneously be found animals of both sexes and almost all age groups. It may be that a more detailed study will allow this point of view to be somewhat modified. UDC 599 -711-5.2 F. G. Chelnokov

MOVEMENTS OF FUR SEALS IN THE ROOKERIES ON MEDNYY ISLAND 151

The tagging of animals serves as one of the methods for studying their biology. The recovery of tags gives the most reliable documentary data in the study of the distribution, migrations and smaller scale movements of animals both over the course of prolonged periods as well as over short periôds of time. Naturally, the reliability of the information obtained, especially in revealing particular regular patterns, depends to a considerable extent on the volume of the data collected.

The tagging of fur seals in recent years has acquired a mass character. It is known that on the fur seal rookeries, located on the shores of islands belonging to the Soviet Union, each year there are tagged from 6 to 9 thousand and more pups, while during the period of the sealing operations there are collected up to several hundred tags. This, undoubtedly, is adequate material for the study of such questions as the mis-

cibility of populations, interchange between islands and certain others. However in the studÿ of the movements of the animals within a single rookery, which is also of considerable

interest, difficulties arise.

Having set ourselves the aim of studying the daily

regime of the fur seals on the rookeries, the distribution

of the different age and sex groups and the interrelationships

between these, the duration of the sojourn of the various

groups of fur seals on the rookery and certain other questions, 2141 we ran into the necessity of elaborating a different type of tag, which would be clearly evident and 'easily readable at a relatively large distance. Our investigations are being conducted on the so-called South-east fur seal rookery, situated on thé-south-eastern tip of Mednyy Island (Commander Islands), where in 1967 there were started experiments on the tagging oe àdult fur seals of various ages with large tags, attached tô rubber collars. The first tags were prepared in a hand-made fashion of white thin sheet-metal 0.25 mm in thickness or out of 1 mm celluloid. Collars of various diameter, designed for putting on the necks of animals of various ages and sizes, were made from rubber from old gas masks. The first tests turned out to be not completely successfull. The tags easily became bent, sometimes broke and even when they remained undamaged then already after 10 - 12 days it was very difficult to read the number of the tag. The collars were Also unsuccessful; they broke easily and the fur seals could remove them fairly simply over their head. Thus, out of 210 bachelors which were tagged in 1968 in various sections of the rookery, on the following day there were found on average 50% of the number of tagged animals, after 10 days - 10%, And ônly a few individual fur seals kept their tags for 18 - 31 days. In 1968 and 1969 these experiments were continued. Besides various modifications of the old tags, there were tested round tags, made up out of two laminae of red plexiglass 3 mm in thickness, which were glued together and between which was placed a leaf of white drawing paper with the serial 242 number of the tag written in large figures. These tags turned out to be more successfull, they were easily detected on the fur seals at a distance of 50 - 60 m and were retained for a longer time than the metal or celluloid tags. The number of the tag could be read fairly easily with binoculars. In 1969 another material was also tested for making the collars, this comprised variously coloured sheet rubber 1 mm in thickness. However it was not possible to achieve much progress since the periods of wearing of these collars were approximately the same as of the collars of the previous models. Thus, the system of collars with large tags should not yet be considered as having been worked out. The investigation of the behaviour and movements of the fur seals within the rookery is still in the experimental stage, but even those few results which it was possible to obtain during this time present a certain Interest. Two groups of fur seals were subjected to tagging with the collars: bachelors, i.e. young sexually immature males, and bulls, to which group belong the adult sexually mature males, the majority of which participate in reproduction. In 1968 there were tagged 92 bachelors, which were located on the so-called bachelor hauling-grounds, i.e. set apart from the harem fur seals. Out of the number that were tagged 38 bachelors were then again observed by us, and 14 of these returned to the sectors from which they had been driven away at the time of the tagging. The remaining fur seals moved over into other sectors of the large South-east rookery and, in the first instance, into those sectors where there are generally formed fairly large bachelor hauling-grounds, 243

In 1969 we attempted to elucidate whether it was pos- o sible to induce the bachelor fur seals to move away from the sectors which they had chosen into other, even if only neighbouring, sectors. For this purpose on the 21st of July on the sector called "Belaya plita" ("White slab"), where no sealing operations were conducted, 94 bachelors were tagged with collars but without the tags, after which over a three day period the fur seals which came out onto this sector were regularly driven off into the sea. Observations showed that on the day following the tagging, the 22nd of July, on "Belaya plita" there were found 438 bachelors, which comprised 87% of the number that had been driven off on the previous day. Among these there were 27 fur seals with collars, or 27% of the number that had been tagged here. In spite of the fairly considerable emergence of the bachelors onto "Belaya plita", simultaneous visual observations permit. one to state that on other sectors of the rookery the numbers of bachelors had increased, and moreover on some of the sectors there were observed fur seals with collars. It is interesting to note that on the neighbouring bachelor hauling-grounds, adjacent to the tagging sector, there were few tagged fur seals (1 on "Dyravyi", 3 on "Chazhnyi"), while on the fairly distant "Zapod'emnyi" sector there were 14 of these (Figure 1). Af- ter they were driven off for the second time the number of bachelors on "Belaya plita" decreased considerably and on the 23rd of July only 237 of these fur seals were found here. On the following days, when the diving-off was discontinued, right up to the end of the commercial season the numbers of 244

\s.

I4'.7384711ail rpla'Cnnece: ,f r 1- Het/pCnyaragna../ 2 - 9900/7fflie•treit. - 347n09bi•;4rietti 4 - 1705ent,»/(61c/- 5- nee/408491 Itoper 6- gel.)///i6it; ■.1 ..""s? 13 7 - 864.9,78b/i/ - deruza nnuma 9.- el:MAW • 1•7111!; 10- 2n7eer16u7 Mornay/lb/CY 2-1C1/9/Ihtti. .2-0/70Cn7flX08.50 q' /2- 0-/2 206roirn78- rIfIckijod/r/7 fa- nporommbiù 1-11 ..701522ciedg /7//aura8.eo, .erecri; ehre- .e/er,reemoW 15-flecmie/Lea .z-/.7.gee,mw f°0 2namilefeil rreicriileog i Soo 4. e Linear scale

Pm. 1. Cxema IOro-nonotiaoro lionucoaoro nexc6au1a Ha OCT- pone MeAuom

Figure 1. Schematic map of tlie South-east fur seal rookery on Mednyy Island

Names of sec-tors : 1 - nepropuskovyi - impenetrable 2 - govorushechii 3 - zapod'emnyi - beyond the "pod'emnyin 4 - pod'emnyi - lifting 5 pestsovaya nora - foxes lair 6 - chazhnyi 7 - dyryavyi - holey (full of holes) 8 - belaya plita - white slab 9 - kamni - stones 10 - glavnyi matochnyi - main maternal 11 - glavnyi kholostyakovyi - main bachelor 12 - II-ya zaboinaya ploshchadka - 2nd killing grounds 13 - progonnyi - driving 14 - 1-ya zaboinaya ploshchadka 1st killing grounds 15 - lestnitsa - staircase ee - settlement - borders of sectors 24,5

bachelors on this sector did not change significantly. Of o interest is the fact that one of the bachelors tagged on "Belaya plita" was later found on Bering Island (on the North- west rookery), although there is no basis for asserting that this occurred as a result of the intervention of man. Experiments on tagging with the collars were also car- 154 ried out on bulls, of which more than a hundred were tagged in 1968 and 1969. Some of the bulls were tagged on the harem sections of the rookery, others in the region of the bachelor hauling-grounds. In 1968 25 bulls were tagged on the harem sector of the South-east rookery, and moreover during the tagging all of these were driven away from the harem-sectors occupied by them on the rookery, while 9 of these bulls escaped into the sea. Already on the following day 22 of the tagged bulls were lying in their former places (micro-sectors) or in the direct vicinity of these, at a distance of 2 - 3 m. After one day the twenty third bull appeared in his old place and somewhat later yet one more bull occupied his place; this latter bull, it is true, prior to this had been noted lying in the bachelor hauling-grounds. Thus, out of the 25 bulls which had been tagged on the harem territory, 24 returned again to their old places. In 1969 39 bulls were tagged in the same manner on the harem territory in the Uryl'e rookery, of which 2 subsequently dropped out of our observations. Of the 37 bulls :,5•1 1.Â remaining under observation, 36 returned to the rookery and occupied their places on the day of tagging, while the one 246 remaining bull simply was not able to push himself through the barrier of other males, although he attempted to return to his sector. Having suffered failure, he did not try again to return to his place in the harem rookery, and subsequently he was observed in a bachelor hauling-ground located not far away. In connection with the polygamous way of life, not all of the sexually mature male fur seals participate every year in the formation of the harems. Some of them cannot win a place for themselves on the harem rookery and dispose themselves on the approaches to this, expecting at the first opportunity to occupy the place of a harem bull which_ for some reason abandons its sector. The behaviour of such bulls is similar to the behaviour of the harem bulls; in any case they are almost as aggressive and not infrequently enter into fights with other males. At the same time a certain proportion of the bulls, even at the height of the harem period, are always located on the bachelor hauling-grounds together with the young males, and moreover in their behaviour they do not differ from the bachelors. The composition of these bulls has not been established but it is assumed that these are either animals which have come to recover after spending part of the reproductive period on the harem rookery or those which, because of their physical features, cannot expect to win a place on the harem territory. With the aim of following up the movements and behaviour of the so-called haremless bulls, in 1968 on the bachelor hauling-grounds of the South-east rookery we tagged with 247 collars 79 such bulls, of which 45 animals were subsequently subjected to observation. The drive of the fur seals to slaughter was carried out from the bachelor hauling-grounds, and on every occasion a certain number of haremless bulls were found to be present together with the bachelors in the drive. In the sorting of the fur seals driven in for the slaughter, these bulls were set free into the sea. Observations on the behaviour of bulls which fall into the drives, which have been made on many rookeries, indicate that in most cases these bulls behave peacefully and ioreover it may be noted that some of these bulls have fallen into this situation not for the first time. The tagging which was carried out by us showed in a documentary fash4n that the bulls not only get accustomed to being.in the drive, but also that after they are set free they again - try to base themselves on the bachelor hauling-ground from which they were captured together with the bachelors. Out of. the 45 tagged bulls , which were under observation, 35 fell into the drives, where they were found among the bachelors that were killed, and only after this Were they let free into the sea. All of them . returned to those sectors from which they had been caught in the drive. Furthermore, 12 of the bulls fell into the sealing drives from one and the same sector on two occasions; one bull was driven with the bachelors on three occasions in an 8 day period, while yet another bull fell into the drives 4 times in 16 days. It may be thought that these animals "understand" that they are 24.8 not subject to the slaughter together with the bachelors, since some of them after being set free from the drive return to their old place, even while the slaughtering of the bache-

lors is being carried out in the vicinity.

Another portion of the haremless bulls behaved some-

what differently. Thus, 10 of the tagged bulls that were set

free from the drive immediately moved to other sectors of

the rookery, although two of these bulls after a few days re-

turned to the same sector from which they had been driven off.

There were also recorded more distant movements of

the tagged bulls. Thus, 4. of the bulls 'were observed on the

Uryl'e rookery, located 16 km from the South-east rookery,

while in 1967 one bull moved away as far as Bering Island,

where it was observed on the North rookery.

CONCLUSIONS

The experiments which we carried out with the tagging

of fur seals with dollars with large tags show that both the

bulls and the young males (bachelors) keep to one and the same

sectors of the rookery. This attachment is- most clearly

manifested in the harem bulls, which always very persistently

try to occupy their own micro-sector, i.e. to return to their

own harem. In doing this they have to overcome the violent resistance of their neighbours and of those bulls which some-

times succeed in occùpÿing the place that was vacated in the

harem. Evidently, most of the harem bulls attain their goal and, if not immediately then after a short time, they return

to their place in the harem territory. 249

The haremless bulls do not have such a stimulus to returning to their old place as is noted in the harem bulls, but in this group of males also there was observed a well expressed attachment to a particular sector of the rookery. Even after having been caught up in the sealing didves most of these bulls return to that place from which they were taken. It is true that among this group of bulls there are more frequently observed movements onto other sectors of the rookery and in a few cases they even accomplish fairly distant migrations, moving from one island to another. In their relations to the sectors which they occupy the bachelors are probably similar to the haremless bulls. In these also there is observed.a certain attachment to sectors of the rookery, to which they also'in the main return after having been driven away. Only.systematic and repeated driving off forces them to move away onto other sectors, and in these cases they prefer to emerge onto those sectors where there are hauled out at this time large numbers of fur seals. In individual cases bachelors are observed to move away over a considerable distance, even moving over onto another island. The behaviour of the haremless males, which get caught up in the sealing drives of the bachelors from the same sectors, indicate, in our opinion, that the fur seals become accustomed to the activity of man on the rookery, finally almost ceasing to be afraid of people, and that the existing concept of the great harm of disturbing the natural regime of the fur seal di rookeries is possibly somewhat exaggerated. 25 0

2 UDC 599.711.5. V. E. Sokolov and N. S. Stepanov

AN EXPERIMENT ON THE RADIO TRACKING OF FUR SEAIS 1 57

THE METHOD OF RADIO TRACKING OF ANIMALS

The ability of marine animals to navigate when moving over long distances, for example, during seasonal migrations over many hundreds and thousands of kilometers, has attracted the attention of investigators. At the present time in the study of the navigational abilities of marine animals the method of radio tracking is attracting more and more attention. This method consists of the tracking of animals, furnished with a radio transmitter, from ships, helicopters or airplanes equipped with a direction finding antenna with a device for reading the bearing, a direction finding receiver and a system for recording and storing the information. Such a system permits one to detect the direction of the animal with the source of the emission of the radio signal. The distance to the animal with the radio transmitter may be coarsely estimated by the amplitude of the signal at the output of the direction finding radio receiver. If at the same time the coordinates of the ship or airplane are determined, one may obtain the position of the animal that is carrying the radio transmitter. 251

A DESIGN FOR A RADIO TRACKING SCHEME

The development of the apparatus for the radio tracking of fur seals in the sea was started with the design of a system for radio tracking. Given certain parameters of the radio link, there were initially determined the basic characteristics of the signal of the directional radio transmittert Carrier frequency = 50 MHz. 2 f car . Pulse repetition frequency f rep. 5 - 15 Hz. Pulse duty factors C = 5 - 10 Transmitting whip antenna Power. amplification factor of the transmitting antenna gl = 1.44. As the direction finding antenna there was utilized a 5-element antenna of the "wave guide" type. The power amplification factor of this antenna g2 = 4.84. The height of the receiving antenna above sea level h 2 = 12 m. In the experiments on the radio tracking of animals in the sea there was employed as the direction finding réceiver a receiver of the R-312 type, with the inclusion at its input

of a pre -amplifier of the "antennal amplifier" type assembled with 2 transistors. • The characteristics of the receiver with the UHF pre- amplifier are as follows: The (signal to noise) ratio at the output of the u ush receiver s = 3. ush Band width 4àf = 6 kHz.

* Translator's note. "pelengatsionnyi i:adioneredatchik" is here translated by "directional radio transmitter', not with the impli- cation that the transmitter itself is directional but that it ls used for direction-finding ourposes. 252

The calculation of the operating range of the- i radio link was started by determining the radio horizon - Dn. The height of the transmitti.ng antenna was accepted as equal

toh, = 1m.

D„ (Knt)-4,12[yh., (ai)-{--Il h2 (hf)1 ,

Dn=4,12(1-{--3,46)=18,3 9.41.

The radiated power of the transmitter P1 was determined

under the condition that the energy range D., = 5 km. The

calculation was made according to the equationa P1•gi•9Z A D,==1^ ^^ ^^• P2

where K the coefficient of non-alignment of polarization of the field of radiation of the transmitter and

of the field of the direction finding antenna.

• This was selected, on the basis of the conditions

of the direction finding, as equal to 0.8;

^l - wave length ; ^6m;

P^ - power, radiated by transmitter;

P2 - power at iriput of receiver, at which there is en-

sured the ratio

" _3. , 11 uc

PZ (OT ) IZnx^(^6c)

1,52X 10-12 2,25 X 10-12 +3 • 10-'4 (ss•) • P2 75 75 253 gZ and g2 - amplification factors of the transmitting and 159 receiving antennae respectively.,

- -. . . _.__ . .. -, D32 • 1G•n2•P2 Pi= k2•%2•gf,•g2

5000'-16.3, 142 -3-10-14 ^ P'- 0,,64•36• 1,44•4,84

25•16 •9,87•3•10-8 _ Pl = = 0,64•36• 1,44•4,84

9,87. 100•0,64•3- 1,4=1•4,t34

9,87 _ 7,37 • 10 ^ er. 192 .' 1,q? .•1,84

Thus, the power radiated by the transmitter should be

PZ = 0.737 microwatts.

SCHENIE AND DESIGN OF TRANSMITTER

The radio direction-finding transmitter, designed for attachment onto fur seals, is a self-exciting generator, operating according to'a "three-point capacitive" scheme. The choice of the scheme of the self-excited generator exerts an influence on the,instability of its frequency. A sufficiently high stability, of the order of 10-6 , is ensured by a scheme with the quartz crystal connected between the collector and the base of the transistor. The setting up of the selected scheme is fairly simple. Without presenting the calculations of the self-excited generator, we will give here only its basic scheme (Figure 1) with the values of its elements. 254

Pile. 1. Cxer,ta paRlioneaenrannonitoro nepegartua:

Ri —100 NAC C4 -- 3000 no R2— 1 Km K1 - 46,7 ..tici4 Ci —5.0+10,0 etwf, 6 —6 PLI, 83 C2 C3 - 4+15 nrfi L, — 0,5 ;welt T — II 416

Figure 1. Layout diagram of the radio direction finding-: transmitter:

R1 - 100 kilo-ohms R2 - 1 kilo-ohm C1 - 5.0 10.0 microfarads 02 = 03 - 4 + 15 picofarads - 3000 picofarads 4 Kb 46.7 megahertz B - 6 RTs 83 L1 - 0.5 microhenries T - pli-16

The transmitter operates in a pulsed (intermittent generation) regime. Such a regime was chosen with the aim of economizing on the power supply and for convenience in dis- criminating animals, on which bearings were taken, by the pulse repetition frequency. In its construction the radio direction finding transmitter has the form of a hermetically sealed, screw-capped duralumin cylinder, 250 cm3 in volume, having a diameter of 52 mm and a height of 70 mm. Gnto the lid of the transmitter were attached a plate with the layout of the self-excited generator, the power source - a 6RTs-83 battery, and the 255

bushing of the antenna. The antenna of the transmitter is

a steel wire, 3 mm in diameter and.1.5 mm* in length, insulated

from the water by means of a vinyl chloride tube. The body

of the transmitter was welded onto a duralumin plate, which

was bent into a.shàpe that corresponds to the curve of the back

of a fur seal. A special Yiarness of two rubber straps and a

leather breastplate allow one to fasten the transmitter reli-

ably onto the animal. The weight of the transmitter, together

with the attachment system, comprises 880 gm.

Another method was also employed for attaching the

radio direction---finding- transmitters onto the animals. •Before

setting free the fur seal into the sea, it was dressed in a

waistcoat, sewn of a strong fabric. The transmitter in this

case was attached to the waistcoat.

Another construction variant of'the transmitter had

the form of a textolite** shell, with dimensions of 110 X 90:

X 60 mm and a wall thickness of 10 mm. In the upper part of

the casing is attached the insulator of the antenna. The con-

struction and dimensions of the antenna are similar to that

described above. From below the casing is covered with a

textolite lid, with.an intervening gasket of vacuum rubber. -

Within the casing are placed the layout of the transmitter

with the tuning elements and and a 1ORTs63 battery power supply.

The total weight of this transmitter comprises 1000 gm.

Translator's notes. Sic. This should probably be 1.5 m. Textolite - a.laminated resin on a cotton or glass fabric base.

:. , ^ ;,z-.:...... ^.,-..^ 256

DIRECTION FINDING ANTENNAE

For carrying out the experiments on the radio tracking and radio telemetry of marine animals there were developed and produced two types of antennae: "the X-shaped double square" and the 5-element antenna of the "wave guide" type. The experiments were mainly carried out with the latter. Its appearance is shown in Figure 2. The principle of its operation has been described in sufficient detail in the literature on antennal techniques. The antenna of the radio direction finding transmitter, having the form of a whip ?)/14, in length, radiates normally polarized radio waves. Consequently, the receiving direction finding antenna should ensure the reception of normally polarized waves. The antenna is composed of an active half-wave dipole,,a reflector and three directors, arranged in the vertical plane. The passive dipoles are fixed directly onto a - duralumin tube, which plays the role of the horizontal boom of the antenna. The active dipole is attached onto a textolite 161 insulating plate, situated on the horizontal boom. The down-lead cable of the RK-75 type is connécted to the halves of the dipole across a matching device, since the input impedance of this anténna is equal to 8 ohms. The horizontal boom of the antenna is firmly attached to the vertical bearing mast. The bearing mast is composed of three sections of duralumin tubing, 40 mm in diameter and 2.5 m in length, which are joined together by duralumin fittings when the antenna is assembled. 257

Pie. 2. hnTimemeirrilag pailicone- neuraumomiafl airreuma TIllla e[30.1- ttoi:ori 6eperouoii cucTemte paRitonpocaenuwailitsi

Figure 2. Èle five-element radio direction finding antenna of the -"wave guide" type of the on-shore system for radio tracking. •

At a height of two thirds along the vertical supporting mast, measured from the foot of the mast, there is firmly fixed a flange with a moulded bearing. Through the inner ring of the bearing passes the supporting mast. Three bracing wires hold it in the vertical position. The lower end of the tube of the supporting mast, which has a pointer for reading off the direction, is affixed in the bearing of the base of the antenna. The flange in the upper part of the base has a graduated circle divided into 360 0 . The down lead cable of the antenna passes down within the supporting mast-. To prevent this from twisting, there is mounted on the supporting mast a stop, which permits the antenna to be rotated within limits of 3600 during direction finding. 258

CONDUCT OF THE EXPERIMENTS ON THE RADIO TRACKING OF FUR SEALS 162

In July - September 1969 the apparatus was tested by the Far-Eastern Expedition Team of the A. N. Severtsov Insti- tute of Evolutionary Morphology and Animal Ecology of the USSR Academy of Sciences in studies on fur seals on Robben Island and its surrounding waters. The radio tracking of the animals was accomplished from the shore and from a ship. The area of Robben Island, on which the tests were carried out, is not greats length 650 m and a width of 150 m in its middle part. In its middle portion the island is rocky. Its upper plateau, which is occupied by breeding colonies of birds and an artificial fur seal rookery, has an altitude of 18 m abova sea level. The main rookery of the fur seals occu- pies the northern, eastern and southern shores of the island. The radio direction finding antenna of the "wave guide" type was set up on the central part'of the upper plateau. The UHF signal from the'antenna was passed on to the input of the R-312 type of receiver. An acoustic display of the signal was employed, with an amplitude method of direction finding. The signals from the radio direction finding transmitters, which were at sea, were also recorded on a tape-recorder of the "Yauza-20" type (Figure 3). Close to the place where the fur seals, on which the direction finding radio transmitters were installed, were set free, there was set up an antenna of the "X-shaped double square" type. On August 15th from the southern cape of Robben Island there were set free two fur seals which had radio direction 259

wom.•-•,•,••••- r.:•••••.7,:e,..1.•;•••tf,,,.-iAte It; ; • e

• e' ; • t(

Pile. 3. AnnapaTypa iipoèfiitinbainin it àartileii iifiiaiiôu nepeRattiniza /%iiipei;ux Hotiii;Éta Figure 3. Apparatus for the acffilStic monitoring and recording • of the signals from thé trânstitteré on thé fur seals.

• • '% 777 -` • , t.• -,'.1"t""I're,..,-- '7-•"%rœ- I'II‘e '- • " • '

.•;.4

1 ..1 1 :11 ..,iM

''-` k, .., • - • - ,Y.• : .,, y t.z...4 ,,,....,..,,....J,:...,..,..;;....;....:,,:à. -.‘ rza,î,-...,..u";...***:-.„, =.,...... ,...-.1•...... “,..-i',....t.,....:ar.-...:-..'...... ,,-..A,,y- ees

Pile. 4. 1-1e-rupex.ienin51 taMËa Mcipci,:bPo konna ã aaupetteletilibiM Ha Bert paAttonepeliaTtniKoM aepea abinyeKom i) _ Mope Figure 4 • A four-year old féMalé fur éal, With an attached radio transmitter 5 béfOré being set free into the sea.

finding transmitters attached to them (Figure 4). The time of release was 15.30 hours. The animal immediately went out to sea. The signals from their transmitters were distinctly 163 monitored by means of the receilier and antenna that had been set up on the rookery. 260

Subsequent tracking of the animals and recording of the signals from the transmitters were carried out by means of the system set up on the upper plateau on the island. The characteristics of the radio direction finding transmitters were as fol.lows :

Transmitter No. 1.

Type of transmitter - 2

Form of attachment - waistcoat

Carrier frequency - 50.62 MHz

Average current consumed - 4.5 mâ.

Pulse repetition frequency - '8 Hz.

Transmitter No. 6.

Type of transmitter - 1

Form of attachment - rubber straps

Carrier frequency - 4•6.7 MHz

Average current consumed - 3.5 ma

Pulse repetition frequency - 4. Hz.

The signals from both transmitters were,monitored in a satisfactory manner ûp until 20 hours on August 15th. Re- cordings were made of the packets of impulses from these on the tape-recorder. At 20 hours the signals from transmitter

No. 6, which had been coming in at a•good intensity (the fur seal at this time was at a distance of about 1 - 1.5 miles from the island), ceased. No signals from this transmitter 16ti• were recorded on the following days. Transmitter No. 1 was monitored periodically up until

11 hours on August 16th. 261

In the interval between 11 and 14 hours on August 16th fur seal No. 1 (according to the number of the transmit -ter it) was not monitored. From 1 • hours on August attached to 16th until 10 hours on August 18th the signals from this transmitter were monitored at a varying level of intensity. In the following monitoring session - 11 hours - there were no signals. On the following two days no signals were recorded from radio transmitter No. 1.

RADIO TRACKING OF FUR SEALS FROM A SHIP

Tracking of the animals at sea was carried out with the help of the sea-going tug "Oberon", aboard which was set up the radio direction finding system. Fur seals Nos. 3, 7 and 5 were set free from the ship at distances of 17, 17 and 14 miles, on the 23rd, 24th and 31st of August respectively. Animals Nos. 3 and 7 were released to the south of the island, while No. 5 was released to the north-west. A plot was made of the course of the ship at sea (Figure 5). The signals of the radio direction finding transmitters were recorded on a tape-recorder. Animals Nos. 3 and 5 set out towards Robben Island. Fur seal No. 7 was tracked for a few hours in the sea, but no signals from transmitter No. 7 were recorded on the day of release and on the following days on the island and in the waters around the island.

262

2.30.9. 6g, 4,33-5.eem m Tepneweg Cape Terpeniya Cape Georgiya ./

no cadev„,; Sibuchii Island 11[121e. .W Re eg/ Rooben (Tyi,ilenii) Island Y ffle

\204. • \

48°Peow */11 30'" ,a • a.m ,› • Pitc. 5. npoimaRiza xo.aa cy,utta B onbrre /44'30'0' `k‘ • pafi.lionpoc.lexuusailmo mopçie.oro Houma M 3 n mope

Figure 5. Plot of the ship's. course during the - test . of the radio tracking of fur s'eal No: 3 asea. •

After the release and tracking of the animals, the 'basic technical characteristics of the radio link were determined: the range of operation and the angular accuracy. The range of operation during the tracking of direction-finding transmitter No. 4, operating at a frequency of 47.77 MHz in conditions of this being on the sui-face of thesea, a force 2 wind and a shipborne operated tracking system, comprised 3 miles. In measuring the range there were simulated the conditions of working the radio link in the case when the fur seal comes up to the surface while it is'swimming. The measured angular accuracy was 5 0 • During the tracking of an animal at sea difficulties arise in reading off the direction. These are determined by the short period of time reception of the signals during the surfacing of the fur seal. This period is most often equal to 1.0 - 1.5 seconds. However the intervals 263 between neighbouring packets of impulses vary within a still wider range. Immediately after the release of the fur seal from the ship these intervals vary between 5 and 15 seconds. Later the intervals become longer. During the passage of fur seal No. 3 over a 20-meter bank the intervals increased to 1.5 - 2.0 minutes.

PRINCIPAL RESULTS

The observations on the fur seals which were subjected to the experiments on shore and in the sea provide grounds for assuming . that the transmitter, which is attached to them, does not cause any marked changes in their behaviour. There were not noted any attempts by the animals to free themselves of the transmitters. The work on the radio tracking of the fur seals may be conducted without disturbing the normal regime of the rookery and without imposing any detriment to the population numbers of the herd. In the process of preparing the experiment it is necessary that there be carried out laboratory investigations and that there be worked out the system of radio tracking under conditions that approximate the natural conditions. The sea trials of the system and also the actual work on the radio tracking of the fur seals may be conducted employing a ship with a tonnage, steaming properties and self- sufficiency that are no less and no worse than those found in an RS*. It is also necessary to carry out theoretical studies

* Translator's note. The Russian abbreviation RS is used for "rybolovnyi sainer" - fishing seine boat, but it may also be used for "rybolovnoe sudno" - referring to fishing boats in general. 264.

on the system for the radio direction finding of animals, î which employs an airplane (helicopter) as the carrier of the radio direction finding apparatus. The results obtained up to the present time from radio- telemetry studies, conducted on marine mammals, allow one to conclude that it is advisable to expand these investigations. Further progress in these investigations is connected with the utilization of high-altitude airplanes and and man- made earth satellites, which would be capable of ensuring the gathering of information from a large number of animals over vast distances. 265

UDC 599-74-5.2 -T. I. Chuvakhina

THE HELn1INTH FAUNA OF THE FUR SEALS ON ROBBEN ISLAND 166

The fur seal is one of the most valuable of the commercial animals that live in the Pacific Ocean. The main value of this animal lies in its fur, which in its beauty and strength surpasses the fur of many terrestrial fur-bearing animals. The meat of the fur seals is utilized as food for fur-bearing animals and for the preparation of feed meal.

From the liver, endocrine glands and sex organs there are obtained valuable medicinal preparations.

The rational utilization of the commercial stocks, as well as the four-country agreement on the conservation of the fur seals have ensured an increase in the population numbers of these valuable animals, including also the population on

Robben Island.

However cases of death of these valuable animals are not rare. The causes of mortality*may be various and among these are helminths. The effect of helminths on the population dynamics of marine mammals has been noted by several investigators (Chapskii, 1938; Kleinenberg, 1956; Tomilin, 1957;

Delyamure and Skryabin, 1960, and others).

Thus, S. E. Kleinenberg (1956) stated that, "Helminths are one of the mortality factors of the white-sided dolphin in the Black Sea". S. L. Delyamure, in his study "The helminth fauna of marine mammals in the light of their ecology and phylogeny", gives a quotation from a study by Isaichikov (1928): 266

"As is known, the North is rich in numerous kinds of very valuable commercial animals (fishes, pinnipeds, reindeer,

fur-bearing animals), which to a considerable extent are sub-

jected to various, often very serious worm diseases (lung- worm disease of reindeer, liver fluke disease of walruses

and seals etc.), which lead to the death of the animals".

In their report on "The helminth fauna of the fur seals

of the Commander lslands" S. L. Delyamure and A. S. Skryabin

(1960) note that among the species of helminths that were

found there are those which may cause emaciation and death

of the fur seals.

Sometimes the parasites are the main cause of the

occurrence of epizootics among the'animals. Thus, on the

Pribilof Islands there were considered cases of mortality of

fur seals caused by the nematode Uncinaria lucasi in 1952,

1953 and 1954. (Jellison and lviilne, 1958). On St. Paul Island in 1957 Doyle established the death

of a juvenile fur seal from the above-mentioned helminth.

In 194.1 Afanas'ev found the nematode U. lucasi in the 167

fur seals on the Commander Islands, although subsequently this

species was not found by anyone on the Commander Islands.

The helminth fauna of the fur seals, living on the

Commander Islands and on Robben Island, have been little

studied up to the present time. There are only fragmentary

data available, which have been obtained on the basis of in-

complete helminthological dissections of a small number of in-

dividuals ( Kro-i;ov and Delyamure, 1952; Skryabin and Delyamure,

1960). Therefore, commencing in 1968, workers from the 2 67

Sakhalin Branch of the TINRO started on a helminthological analysis of the fur seals of Robben Island. The results of the helminthological investigations, carried out on Robben Island in 1968, are presented in the present paper. In the 1968 season by the method of complete helminthological dissections, in which every organ is thoroughly examined, 58 fur seals were studied. The material was fixed by the generally accepted methods. Animals from 2 to 9 years old, inclusively, were subjected to dissection. The age was determined from tags that were removed from the dead seals. 45 males and 13 females were examined. Out of the 58 dissected animals, 57 were found to carry helminths, but not all of the investigated organs were infested with these. The heart, lungs, liver, kidneys and pancreas were found to be free of helminths. The stomach, all sections of the intestine and the oesophagus were infested, and some of these were very intensively infested. The highest infestation was found in the caecal section of the intestine (68.2%) and stomach (63.1%), then in the rectum (54.3A) and large intestine (52.6M, more rarely in the small intestine (47.3) and duodenum (19.2%). Least infested was found to be the oesophagus. The parasites found belong to three classes: cestodes, nematodes and acanthocephalans. We did not find a single species belonging to the class Trematoda. According to the data of Delyamure and Skryabin (1960) in the Kuril fur seals there were recorded 5 species of helminths, of which the parasite Bolbosoma nipponicum (1939) was not found present in our material, although previous authors 268

(Bobrova, 1949; Krotov, 1952) had reported the presence of this in the fur seals of Robben Island. According to the 1968 studies the helminth fauna of the fur seals of Robben Island was represented by 8 species, belonging to 6 genera: Diphyllobothrium, peamicocephallus, Contracaecum, Terranova, Bolbosoma and Corynosoma. The class Cestoda was represented by 3 species, belonging to two genera. Of the genus Diphyllobothrium (Cobold, 1858) there was found D. krotovi, which had been found previously in the Kuril (RobbenIsland) and Alaskan fur seals (Delyamure, 1955). The infestation rate with this species of helminth in our material was not high and comprised 15.7%. It was localized in the small intestines. A second species, D. lanceolatum (Krabbe, 1885) had been noted previously in the ringed seal, the Okhotsk ringed seal, the monk seal and guinea pig (Delyamure, 1955). In our material the frequency of occurrence of D. lanceolatum was insignificant. Out of the 57 infested fur seals only two carried this species of parasite. The site of localization was the caecal section of the intestine, the intensity of infestation was 1 - 2 specimens. To the genus Pyramicocephalus (Monticelli, 1919) belongs the species P. phocarum, which had been previously recorded in the following marine animals: Steller's sea-lion, bearded seal, hooded seal and ringed seal. The places of finding in the waters of the Soviet Union ares Nokuev and Kotel'nyi Islands, Novaya Zemlya, the White and Barents Seas. The Kuril fur seal is a new definitive host of P. phocarum. This cestode was found in 112 out of the 57 infested 269 • • fur seals (73.7). P. Phocarum was recorded in all sections • of the intestine, but the main organ of its localization was the large intestine, while the duodenum was the organ with the lowest infestation. The highest intensity of infestation was found in the caecum and the lowest in the rectal section of the intestine. The nematodes were represented by two species (we are not taking into consideration the nematodes, the species affinity of which has not yet been established), belonging to two genera. To the genus Contracaecum (Railliet et Henry, 1912) belongs the species C. osculatum (Rudolphi, 1802). In the waters of the USSR this species has been found in the following animais (Delyamure, 1955)1 the'Okhotsk ringed seal, harp seal, bearded eal, Kuril and Alaskan fur seals. The places of finding were: White Sea, Novaya Zemlya, Gukera Island, Tikhaya Bay, Franz Jozef land, Karskiye Vorota Straight, Loginova Island, the Novosibirskie Islands and the Sea of Okhotsk. 20 fur seals out of the 58 studied were carriers of this species of parasite (35.1%). The highest frequency of occurrence was in the stomach and rectum. Of the genus Terranova (Jeiper et Atkinson, 1914) we found the species Terranova decipiens (Krabbe, 1878, Baylis, 1916), and moreover this nematode had already been noted previously in the fur seals of Robben Island. Among the definitive hosts also are the Steller's sea-lion, the southern fur seal, the walrus, the ringed seal, the Baikal seal, the Okhotsk fur seal. the monk seal and others. We recorded this species in 17 out of the 57 fur seals (29.8i'0). They infest al]. sections 270 • • of the digestive tract and are frequently found simultaneously in several sections of the intestine. The intensity of infestation was from 1 to 20 specimens. The acanthocephalans were represented in our material by three species, belonging to two genera, of which two species belong to the genus Corynosoma (Ziihe, 1905). The first species has the following definitive hosts: Steller's sea-lion, walrus, grey seal, common seal, harbour seal, ringed seal, the Okhotsk ringed seal, Caàpian Seal, the White Sea harp seal and 169 others. The fur seal has also been previously noted as a host of C. strumosum. In our material 14 fur seals were found to be carriers of this helminth. These parasites are found in all sections of the intestine. The intensity of infestation ranged from 1 to 10 specimens. The second species C. semerme (Forssell, 1904) is parasitic in the following marine mammals: grey seal, common seal, ringed seal, walrus and the harbour porpoise. C. semerne was recorded in 4 fur seals on Robben Island. Its localization was in the caecum and large intestine, and the intensity of infestation ranged from 1 - 7 specimens. Of the genus Bolbosoma (Porta l 1918) there was found only one species, Bolbosoma bobrovi (Krotov et Delamure, 1952), which had been previously recorded in the fur seals on Robben Island and in Steller's sea-lion. En our material this species was recorded in the caecum of a two-year old male as a single specimen. In the fur seals there may simultaneously be parasitic representatives of one, two or even three systematic classes. Thus, out of the 57 infested animals, 6 were infested with nematodes (10.5%), 5 with cestodes (8.7%), 2 with acanthocephalans 271

(3.5^?^), 22 with nematodes and cestodes (38.570) and 18 of these

fur seals were infested with cestodes and acanthocephalans

(31.5J). The parasites were found in the number of from one

to several hundred specimens.

The number of helminths in fur seals of different ages

was not uniform. In comparing the average intensity of infes-

tation with the ages, we note that the highest number of hel-

minths was found in the two-year old fur seals, 30 parasites

per one infested animal. The total number of helminths found

in the two-year old animals was 4,21 specimens. In the.three-

year olds there were found 13.5 parasites per one animal (a

total sum of 167 specimens). For the foizr-year olds, with a

total sum of 154- specimens, there were 17.1 parasites per ani- ^^. mal. in the five-year old fur seals the total number of he -

was min-ths ^^238 specimens, averaging 17 spe cimens per one infés-

ted animal. The smallest number of helminths was found in the'

six- and nine-year old males.

in their study on "The helminth fauna of the hooded

seal (Cystovhora cristata), inhabiting the Greenland Sea"

Delyamure and Treshchev (1966) noted that "the drop in the

rate of infestation in the older animals occurs, on the one

hand, as a result of a "self-purification" of the animals rid-

ding themselves of the helminths and, on the other hand, through

the mortality of the most highly infected of the animals".

4°r'hile collecting the helminths we paid attention to.

pathological changes in the organs, in which the parasites were ! i^ localized, which were manifested in the form of small ulcers in the mucosa of the intestine and stomach. The degree of des-

truction of the mucosa varied. 272

While dissecting an 8-year old fur seal there was found a perforation of the stomach. The diameter of the ulcer was not great, but the action of the helminths was evident. The worm infestation had obviously affected the condition of the animal, since this bull was extremely thin. At the present time, however, we cannot speak firmly of an effect of the helminthe on the condition of the fur seals, since we do not have sufficient information on this question. Further studies on the helminth fauna of fur seals are necessary for the purpose of elucidating questions concerning the seasonal infestation and the infestation of fur seals of different ages, concerning the size of the helminth-induced mortality and the effect of thé helminths on the condition of the animals.

REFERENCES

1. Afanas'ev V. P. The parasitic fauna of the commercial mammals of the Commander Islands. Uchenye zapiski LGU, ser. Biologii (Scientific Notes of Leningrad State University, Biological Series), vol. 74, no. 18, Leningrad, 1941. 2. Delyamure S. L. The helminth fauna of marine mammals in the light of their ecology and phylogeny. Izd-vo AN SSSR (Publ. USSR Academy of Sciences), 1955. 3. Delyamure S. L. and Skryabin A. S. The helminth fauna of the fur seals of the Commander Islands. "Biologi- cheskie nauki" ("Biological Sciences"), No. 2, "Vys- shaya shkola", 1961. 273

Delyamure S. I. and Treshchev V. V. The helminth fauna of the hooded seal (Cystophora cristata), inhabiting the Greenland Sea. Zoologicheskii zhurnal (Zoological Journal), vol. X, No. 12, 1966. 5. Kleinenberg S. E. Mammals of the Black Sea and the Sea of Azov. Publ. USSR Academy of Sciences, 1956. 6. Krotov A. I. and Delyamure S. L. Contributions to the parasitic worm fauna of mammals and birds of the USSR. Trudy Gel'mintologicheskoi laboratorii AN SSSR (Trans- actions of the Helminthological Laboratory of the USSR Academy of Sciences), vo. 6, 1952. 7. Tomilin A. G. Animais of the USSR and adjacent countries. vol. IX, Cetaceans, Publ. USSR Academy of Sciences, 1957. 8. Chapskii K. K. The bearded seal of the Kara and Barents Seas. Trudy ArktichNII (Transactions of the Arctic Research Institute) vol. 123, 1938.

JINTEPATYPA Arfianacbea B. 17. Ilapaatrrod)ayna npontucaonbtx nuteKontrratonex Kontan- AopcKnx ocTponon. ',Sktentare aanumit JIFY, cep. 6no.norttir, T. 74, umn. 18, JI., 1941. 2 ,11e.a.n.mype C. J/". Feahntuirroqlaria ntopctutx nizteKonnTatoLnux B cneTe nx n (i)naorenttn. 11a-no CCCP, 1955. 3 ,1Ze.n.R.Itype C. J7.,. Cvniitut A. C. reobnunrrocPayna -Kontati.aopcmix. mopciatx No- T111:013., eBnonornttecHne Ham». N'c 2, ‹Bbictuan unzona», 1961. . ,lledmitype C. Tpetucti B. B. 0 rennnurrocimpte xomana (Çystophora cristata), o6nTatotnero B rpenaanncNom ntope. 300aortm. azypitaa, T. X, BbIH. 12, 1966. KlIefiffeil6CPC C. E. Maelzontiriticuote T-Ieptioro H A3OBCK.01.0 ntopert. 1.13R-no AH CCCP, 1956. 6 xpoToa A. II., ec...2.q..ifype C. •17• MaTeptumbi K (Impie HaPa3HTWIECKIIX nepneii ISIJICK0MITa1011111X. H nTint CCCP.•Tpyiet FCab1111111. .1a6opaToptut A1-1 CCCP, T. G, 1952._ Tomimun A. F. 3nepn CCCP H rtpitamainux. cTpatt. T. IX, KuToo6pa3nutc, 113R-no AI-I CCCP, 1957. 8 tlancmul K. K. Mopci;oil aanu KapcNoro u Bapenuena mopert. Tpyitht Apwrirt. H1111, T. 123, 1938. 274.

UDC 599.745 O A. M. Nikolaev

MIGRATIONS AND LOCAL REGROUPINGS OF THE KURIL SEA OTTER

The distribution of sea otters along the islands of the Kuril ridge bears a markedly expressed seasonal character. This occurs as a result of the movement of the animals from their winter stations to their summer stations and conversely, as well as a result of the approach of the ice to the islands. In the warm period of the year (May - September), when on both coasts (the Okhotsk and Pacific) of the islands there are present numerous growths of seaweeds on the surface of the sea, the animals live on various sides of the islands, since everywhere there are found fields of seaweed that play the role of resting places for the sea otters and shelters from their enemies and from bad weather. From May to September in the Kuril Islands there occurs relatively calm, though also cloudy weather, and therefore the sea otters do not undertake distant movements. During the cold period of the year the animals are frequently forced to take cover from the violent north-west winds. With the onset of the period of the strong north-west winds, which destroy the fields of seaweed, the majority of the animals, which during the warm part of the year live on the Sea of Okhotsk side of the islands, move over onto the Pacific leeward side. During this translocation some of the animals settle on the extremities of the islands, where they can rapidly take cover from bad weather on the leeward side. 275 , .

In the winter on the Sea of Okhotsk side of the Kuril ridge

there remains an insignificant number of sea otters, living

near small stony islets, though the latter provide poor pro-

tection to the animals from bad weather.

Such a distribution of the animals off the islands

is maintained with only slight changes from the middle of

autumn until the approach of the ice.

The sea otter does not make holes in the ice and there-

fore it does not live in places where landfast ice is formed

or where there occurs drift ice, creating heavy ice conditions.

From a map of the ice conditions in the Sea of Okhotsk

it is evident that in a severe winter there remains completely

free of ice only the middle part of the ridge (Ketoy - Onekotan).

In spite of the cold Sea of Okhotsk, and the Penzhinskoe

and Kuril'skoe currents, which lower the water temperature to

-1.8°C, ice is not formed along the Kuril ridge but is brought

here by currents and winds. The ice moves down to the northern

part of the ridge from K_amchatka, ^ and to the southern part -

from Sakhalin.

From the eastern coastal regions of Kamchatka the ice

drifts down to the south and in January-February approaches

up to the island of Shumshu, the east coast of Paramushir, and

then even up to Onekotan**. On the western side of Paramushir

* During severe winters the western coastal region of Kamchatka is completely covered by ice, along the east coast considerable accumulations of ice are observed only to the north of Avachin- skaya Bay, to the south of this there are only small amounts of landfast ice and separate fields of drift ice. ** G. V. Steller (1?51) even mistakenly considered that there were no sea otters to the south of Onekotan, since the ice does not move down further to the south than this island. 276 ice occurs rarely, it is brought here by the current frein the west coast of Kamchatka. However cases do occur when the ice encircles Atlasova Island and completely blocks up the strait between Paramushir and Shumshu islands. G. V. Steller (1751), S. P. Krasheninnikov (1786) and other investigators reported that in thosedistant years the inhabitants of the northern Kuril Islands (Shumshu, Paramushir and, in part, Atlasova) waited for January-February in order to begin the hunt for the sea otters, which appeared there on the adjacent ice. This occurred for the reason that each year the ice forced out the sea otters from the western coastal region of Kamchatka, where there were probably many of the animals at that time. It should be assumed that a considerable part of the East-Kamchatka population of sca otters also overwintered Dn the north Kuril Islands, since along the eastern coast of Kam- chatka there are few small stony islets, which are so necessary to these animals during the cold period of the year. Our opinion is corroborated by the information given by I. D. Dobrovol'skii (1936), who noted, on the basis of observations on the conservation of the sea otter hauling-out grounds (the east coast of Kamchatka), that the sea otters move to their winter quarters that are mainly on the hauling-out grounds of the Kuril ridge. At the present time there are also observed seasonal translocations of the sea otters from Kamchatka to the northern Kuril Islands and back. However the sea otters are now rarely seen on the ice off the Kuril Islands. This, probably, is explained by the fact that there are few sea otters off the 277 • west coast of Kamchatka, while the animals which live off East Kamchatka du ring the warm part of the year apparently

leave for the Kuril ridge long before the approach of the ice

to its northern islands.

On more than one occasion we were able to note consi-

derable seasonal fluctuations in the numbers of the sea otters

off the north-eastern shores of Paramushir and off the Ptich'iye

Islands, which are located in the same region. These fluctu-

ations also we attribute to the seasonal translocations of the

animals between Ka.mchatka and the northern Kuril Islands.

Since the eastern coastal region of Paramushir abounds

in small stony islets, in mild and average winters the sea

otters do not move away from here to go anÿwhere else. It is

possible that in very severe winters some of the animals move

away from Paramushir to Gnekotan or other more southerly islands,

which was reported to us by.the inhabitants of Cnekotan and

Kharimkotan. There are no sea-otters on the western side of Para-

mushir and thèrefore the seasonal translocations of the ani-

mals on this island are limited to the autumn movement of the 173

animals away from the thinned-out fields of seaweed to the

small stony islets, and to the return movement in the spring.

In the middle part of the Kuril ridge (Onekotan - Ketoÿ),

where there is no ice, the animals accomplish their seasonal

movements from the seaweed fields (in the autumn) to the stony

islets and in the reverse direction (in the spring), and more-

over some of the animals, living on the Okhotsk Sea side of

the islands during the warm period of the year, move over to the Pacific side at the beginning of winter and return back in

the spring. 278

It should be noted that in this part of the ridge, with the exception of southern Onekotan and the Makanrushi Island, the seaweed fields are found not far (up to 1 km) from the shore, as a consequence of the fact that the off- shore region of the islands is relatively very deep almost everywhere. The seasonal regroupings of the sea otters, caused by changes in the hydrometeorological conditions, have also been noted in the Aleutian Islands. N. V. Slyunin (1895) wrote: "Past history, however, shows that the beavers (sea otters) moved away for the summer and returned in the winter in the severe frost, both, for example, near Umnak Island and on Sanak Island". The sea otters accomplish their most considerable migrations under the influence of the ice. However, different ice conditions are set up in different parts of the ridge. The most difficult ice conditions for the sea otters occur off Kunashir, Iturup and Urup Islands. Here the ice appears from Sakhalin and initially (January, February) it covers the coastal region off Kunashir, then it moves on towards Iturup, the islands of the Lesser Kuril ridge and Urup. Off the last named island the ice occurs in March-April. Of the islands of the Lesser Kuril ridge only the northern coastal region of Shikotan is covered with ice, while off the other islands there appears only open pack ice. Every year much drift ice comes up to the Okhotsk Seacoast of Iturup, but on the ocean side of the island there is generally no ice. Most frequently only open pack ice approaches Urup Island, but sometimes the Okhotsk Sea coast of this island is invested with 279 such closely packed ice that one may freely cross the bays over this ice. Still more rarely such ice envelopes the northern and southern extremities of the island. The most severe ice conditions were observed off Urup in 196, 1967 and 1969. In 1960 a large part of the Pacific coast of the island was packed with ice. It is important to note that even in the period of the greatest approach of the ice up to the island (1960) the "Urup" population of sea otters' was not destroyed, although, of course, the loss of animals was increased. According to a verbal communication from G. I. Saenko, an inspector of the Sakhalin Fisheries Service, in 1967 the sea otters left the north-west part of Urup about one day before the approach of the ice. During periods of severe ice conditions some of the animals are always found to be "squeezed" by the ice up to the shore. In such cases the animals keep themselves to small, shallow water sectors along the coast that are free of ice but which have a poor food base. If the ice covers even these last sectors of open water, then the animals perform very difficult, mainly nocturnal, migrations across the ice in search of open sections of sea. During severe ice conditions the "Urup" sea otters have already on several occasions attempted to cross over the island from the Okhotsk Sea coast, which was closely packed with ice, to the Pacific coast. Thus, in the spring of 1961 a female attempted to cross Urup in the region of Kompaneiskaya Bay. The animal moved upstream over the ice on the river for a distance of more than 4. km, where it was found. At about the same time three animals were 1 280

observed on the ice of Lake Takotan (Urup) at a distance of

0.5 - 0.7 km from the shore. In April of 1969 on the north-

west coast of Urup a small group of sea otters were "squeezed"

to the shore by the ice. The animals were found to be so

helpless that inspector G. I. Saenko of the Sakhalin Fisheries

Service was able to successively carry 8 sea otters over onto

the eastern side of the island, where there was no ice.

It should be noted that in April 1969 the ice extended

along the ridge from south to north considerably further than

was normally the case and it stretched along the Okhotsk Sea

side of the ridge as far as the northern tip of Simushir.

Several approaches of the sea otters up to Sakhalin

have already been noted, though there are no sea otters off

the Japanese islands. It is probable that the animals which ii came up to Sakhalin overwintered off the shores of Japan,

whither they were driven down by the ice from the Kuril ridge.

Information about the overwintering of sea otters off the

coast of Japan is present in the publication by N. V. Slyunin

(1895). He wrote t "From the Japariese information it became

clear that the beavers (sea otters) appear on the hauling-out

grounds off the Japanese coast in November and leave inNay".

S. V. Marakov (1964.) reported that in January of 1960 a'large

sea otter was accidentally killed in the Smezhnaya River (Ust'-

Ka.mchatskii region) approximately 20 km from the sea. In this

case, apparently, the ice forced the animal to move up into

the river. A still more sensational case occurred on the 12th of

November 1966, when a sea otter was found at kilometer 26 of the highway connecting the Arctic port of Pevek with the 281

"Komsomol'skii" placer mine. Judging by the photograph, this was an adult but very emaciated sea otter, weighing only 17.7 kg. The animal was found far into the tundra (20 km from the shore of Chaunskaya Bay), probably as a consequence of the fact that the sea was covered with ice and so it was forced to seek an open body of water. It is possible that this sea otter had been moving for a certain period of time along a river and had fed in unfrozen patches of water in the midst of the ice (Personal communication from A. G. Pyn .ko, Head of the Okhotsk Fisheries Service). in addition to the translocations of animals caused by seasonal changes in the hydrometeorological conditions, there are also known mass migrations of sea otters, occurring under the influence of intensive hunting or severe volcanic activity. In the report by P. Tikhmenev (1863) we find the following statement on this subject: "The prolonged hunting ban on Urup, where at the beginning of the 'forties the beavers (sea otters) had disappeared completely, also improved the state of affairs, and now the hunting on this island may be considered as quite abundant. The eruption at this time of the volcano on Simushir (Nt. Prevo) also drove the animals away from these Places, though this misfortune was recompensed after a time by the augmentation of the hunting on the other islands of the Kuril ridge. In general, as has been noted by some people, the sea beavers (sea otters) sometimes did not depart completely from the Kuril Islands, but disappearing in one place they appear in another, i.e. unsuccessful hunting at Urup was compensated at Shumshu, or on the 13 m and 14• m island etc., although, of course, not always to the same degree. 282

And even in recent times the frequent earthquakes on these islands and the caustic ash, discharged by the volcanoes, were a cause of the beavers (sea otters) moving from one place to another". I. I. Brabash-Nikiforov (1947), E. D. Il'ina (1950) and others have reported that in 1872 there occurred a second settlement of .the Commander Islands, though the animals commenced living only on Mednyy Island. The mentioned authors were inclined to see the causes of such a massive resettlement of the sea otters again in the intensive persecution of this animal on the Kuril Islands, where in addition there occurred severe volcanic eruptions. In all periods of the year the sea otters daily accomplish certain small translocations, connected with the search for food or shelter from bad weather. These movements generally do not exceed 30 km. Since during periods of severe ice conditions many sea otters die each year, all possible measures for rescuing them should be undertaken. Above àll it is necessary to strengthen the conservation of the sea otters on Urup and southern Para- mushir (Cape Vasil'eva), where the number of inspectors of the Sakhalin Fisheries Service is extremely inadequate. These measures are necessary not only for rescuing sea otters, which are found to be in a difficult situation, but also for the timely gathering of the pelts of animals that have died and for the final eradication of the illegal hunting of these very valuable animais. 283

JI FITE PATY P A

1 Bapa6atu- HuKurpopoo 11. H. Ka.rum, ero 6nonorun n salmon' xooniiersa. C6. cl(anan. 1-131L Fji. yup. no 3anolieR. M., 1947. 2 fiocIp000.lbcKtdc II. R. jlanarunemni 6o6pooldi oanonen• nuK. 3anonenumw Aaohnenocrotmoro Kpan, Xa6aponcK, 1936. !Lamina E. R. OCTp013110e. 311Cp0BORCTBO. Mcwoyuaponnan mura. M., 1950. L. gpatuenuHrtuKoo C. 11. Coutcanue oeman KaWlaTiili, T. 1-2, C-116., M., 1786, 1949. • •5 Huno.wee A. M. Bonpow oxpaubt u pacceaeuun Na.lanon na ocrpouax. Ky pu..,7I,CE011 rpnnht. C6. «MOKKI1C m,:ieKorurraiontue». M., «l-layKa», I9 69. CA10111111 H. 13. Ilpombunonme 6oraTeTua KamtiaTim, Caxaanna u I(omaunop- cKux oerpouon, Hon. ).1,cr. oemacn. C-116., 1895. 7 Tux.mettes 17. 1.1c-ropuoccmul o63op o6pa3omuum PocenfteKo-AmepuKancKofi Kci,ranannu ce oeficrnun no nacronmero npemenn., 2. c,n(5., 1863. • Heller G. W. De bestiis marinis. Nove comment. Acad. Sei, Petropol, t, 2, ni51.

REFERENCES.

1. Barabash-Nikiforov I. I. The sea otter, its biology and questions of husbandry. Symp. "The sea otter". Publ. Main Directorate for Reservations. Moscow, 1947. 2. Dobrovol'skii I. D. The Lapatinskii sea otter reservation. Reservations of the far-eastern territory. Khabarovsk. 1936. 3. Il'ina E. D. Insular fur farming. International book. Moscow. 1950. 4. Krasheninnikov S. P. A description of the land of Kamchatka, Vols. 1-2, St.-Petersburg, Moscow, 1786, 1949. 5. Nikolaev A. M. Questions concerning the conservation and resettlement of sea otters on the islands of the Kuril ridge. Symp. "Rarine mammals". Moscow, "Nauka", 1969. 6. Slyunin N. V. The commercial resources of Kamchatka, Sa- khalin and the Commander Islands. Publ. Det. Agriculture. St-Petersburg. 1895. 7. Tikhmenev P. Histoi-dcal review of the formation of the Russian-American company and its actions up to the present time. 2. St-Petersburg. 1863. 284.

SECTION

THE MORPHOLOGY AND PHYSIOLOGY OF MARINE MAIM'S AND OTHER QUESTIONS

- • • 285

UDC 599 •S + 599-74-5 E. T. IVANGVA

THE MORPHOLOGY OF THE VASCULAR SYSTEM OF 179

CETACEANS AND PTNNIPEDS

The vascular system, including the arterial, venous

and lymphatic systems, is adapted in various ways to life in water in the aquatic (cetaceans) and semi-aquatic (some representatives of the insectivores, rodents, carnivores and ungu- lates and the pinnipeds) mammals.

One of the specific structures of the vascular system

of whales is the rete mirabile, or retia mirabilia, which was

already known in the time of -Ty'son (1680) and Mono (1787).

Various roles have been ascribed to this, including that of

a reservoir for reserve blood during submersion and the.tempo-

rary cessation of breathing (ümmaney, 1932; Slijper, 1932,

1962; Irving, Scholander and Grinnel, 194•2, and others),

and also the function of evenly supplying arterial blood to the brain (Nagel, Morgane, McFarland and Galliano, 1968).

In the semi-aquatic mammals, including also the seal.s,.

the reservoir for the reserve blood is most frequently formed

by the veins, represented by sinuses, plexuses, anastomoses

and collaterals (Harrison and Tomlinson, 1956; Barnett, Har-

rison and Tomlinson, 1958; Harrison and Tomlinson, 1963, and

others ) .

What is the relationship to the rete mirabile and

auxiliary specific structures of the other portions of the

vascular system (both the blood and lymphatic systems) and DUE DATE

201-6503 Printed in USA