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Proceedings of a Symposium on Ecology and Protection of the Kuril Seal, Sapporo, 1985 (Summaries)

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Proceedings of a Symposium on Ecology and Protection of the Kuril Seal, Sapporo, 1985 (Summaries)

The Organizing Committee of the Kuril Seal Symposium (Representative : Kazuo WADA Primate Research Institute, Kyoto University, Inuyama 484, Japan)

1) On the Symposium on Ecology and Protection of the Kuril Seal

In order to summarize the researches and protection movements of the Kuril seal (Phoca vitulina stejnegeri) in Japan during these twelve years and to create a further step in their progress, a symposium was held under the joint auspices of the Marine Mammal Research Group of Mammal Research Association, the Kuril Seal Research Group, the Research Institute of North Pacific Fisheries of Hokkaido University and the Mammalogical Society of Japan, at the Northern Region Center, Sapporo, on 10-12 July 1985.

The symposium was indebted to the support and collaboration of the following organiza-tions, and many individuals. The committee of the symposium wish to express their sincere

appreciation of their favors.

The Nippon Life Insurance Foundation, the Northern Regions Foundation, the Northern Region Center, the World Wildlife Fund Japan, the Japanese Association of Zoological Gardens and Aquariums, the Nature Conservation Society of Hokkaido, the Hokkaido Shimbun Press, the Hokusui Society, the Hokuren Federation of Agricultural Cooperatives, the Hokkaido Gas Comany Limited, the Kamori Kankou Corporation, the Seibu Construction Company Limited, the Editorial Office of Anima (Magazine of Natural History) of Heibonsha Joint-Stock Company and the Editorial Office of Newton (Graphic Science Magazine) of Kyoikusha Joint-Stock Company.

On the five subjects 25 lectures, including those by three famous scientists invited from the United Kingdom and United States of America, were addressed to an audience of about a hundred, and there was eager discussion on each lecture throughout the three days. On the third day, an appeal for protection of the Kuril seal was adopted at the general discussion unanimously, after a heated debate including speeches by fishermen engaged in salmon trap net fishing.

We hope to keep a record of the symposium ; summaries of lectures and the •gSapporo Appeal•h. We are much obliged to the Editorial Committee of the Mammalogical Society of Japan for their giving us an approval to publish the record in the journal of the society. And we express our heartfelt gratitude to Mr. W. N. Bonner, British Antarctic Survey, Natural Environmental Research Council and Mr. S. Azuma, Primate Research Institute, Kyoto University for their revising the manuscripts with great care.

Along with the symposium, the following four events were held ; a photoexhibition introducing the Kuril seals (on the theme of •gCorrespondence from the Rough Reefs•h, on 8th-12th at Aurora Plaza, an underground plaza in Sapporo) ; a night session (on the theme of •g Fauna in the Shiretoko Peninsula•h, •gMain Breeding Grounds of the Kuril Seal•h, •gDiving

Depth of the Northern Elephant Seal•h and •gGeographical Variation of the Pelage Pattern of the Kuril Seals along the Northern Pacific Coast•h, on 10th at the Faculty of Agriculture of Hokkaido University) ; a public lecture with a documentary film (on the theme of •gThe Seals

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on our Northern Shores•h, on 13th at the Kita-ichijo Assembly Hall of the Hokkaido Shimbun Press), and an excursion for one of the habitats of the Kuril seals (on 13-15th. The destination

was Gome-iwa Rocks, a breeding ground of the seal on the shore of Hamanaka-cho, Kushiro).

An additional note : We plan to publish a book entitled •gEcology and Protection of the

Kuril Seals•h, sponsored by the Nippon Life Insurance Foundation, from the Tokai University

Press in November, 1986. (Tetsuro IToo)

2) Summaries of lectures

a : The aim and present status of the Kuril seal protection movement

The object of the Kuril seal symposium

Kazuo WADA Primate Research Institute, Kyoto University, Inuyama 484, Japan

The object of the present symposium shall be to create a concrete and effective

counter-plan, at present and in the future, for Kuril seal protection.

Upholding a designation of the seals as a precious natural product for their protection, we

have carried out for a little over ten years many investigations to make clear the biological

characteristics of the seals and actual condition of seal damage to coastal fisheries. We hope

to discuss thoroughly, based on the substance of these investigations, the following themes :

biological characteristics of the seals on the first day, seal damage to the fisheries and research

conducted in the United Kingdom and the United States of America on the second day, and

the relationships between seals and fisheries from historical, administrative and legal points

of view on the third.

It is worth special mention that persons interested in fisheries are asked to be present at

the conference. In the past, conferences of this kind used to be held with attendance from the

protection side only, but at this time we expect straightforward discussion from fishermen

concerning actual damage by seals.

It is a great pleasure for us to have three famous research workers from two foreign

countries at the conference, and we expect them to furnish material rich in content. Also we

hope they will give us frank comments and advice from the viewpoint of countries having not

only more abundant experience in research and citizen movements, but also more advanced

systems of legislation and administration of the seals.

If a consensus of opinions are attained among the participants through discussions from

many-sided points of view concerning the abovementioned problems on the last day, it would

assist greatly the persons participating, at present and in the future, in research and protection

movement of the seals.

Our investigations and research on the Kuril seals up to now, and the conference are

indebted to the support and collaboration of many organizations and individuals. On behalf

of the committee of the conference, I wish to express our sincere appreciation for their kind

assistance.

b : Biology of Kuril seal

Present status of Japanese pinnipeds

Tetsuro IToo First Department of Oral Anatomy, School of Dentistry, Asahi University, Gifu

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A general view on the present status of eight Japanese pinnipeds is as follows : Popula-tion size of the northern fur seal (Callorhinus ursinus) is estimated at 1.765 million animals throught the world. They are pelagic and stay along the coast of Sanriku from January to April, and from May to July leave the waters of the western coast for the northern Pacific. A separate stock of the seals migrates to the Sea of Japan until June. Along the coast of the Sea of Japan satisfactory information about their migration has not yet been gathered.

In Asian waters the Steller sea lion (Eumetopias jubatus) breeds on the Kuril Islands and on islands in the Okhotsk Sea. Their total population is estimated at about 6,000 animals. The sea lions come down to the coast of Hokkaido and stay there during winter and spring. Some groups of them occur along the coast of nothern Hokkaido (ca. 1,000 individ.) and another herd, 3,000-5,000 in maximum number, migrates to Nemuro Strait. In recent years the number of animals, range of migration routes and number of haul out rocks have greatly decreased throughout the areas.

There are no records of the Japanese sea lion (Zalophus californianus) through the last 40 years ; they have already been exterminated in Japanese waters.

Four phocid seals occur in Japan in addition to the Kuril seal (Phoca vitulina stejnegeri) ; these are the larga seal (P. largha), the ribbon seal (P. fasciata), the ringed seal (P. hispida) and the bearded seal (Erignathus barbatus). Population sizes of the first three in the Okhotsk Sea are estimated at 168,000, 140,000 and 800,000-1,000,000 animals, respectively. That of bearded seal in the north Pacific is 450,000 animals. These pagophilic seals migrate to the waters off Abashiri and the Nemuro Strait during the season of drift ice, but their number has not yet been surveyed. Some hunting records show that 1,500-10,000 seals were captured annually during 1968-1976 in the waters off Abashiri, including the coastal waters of Skhalin, and about 1,000 seals were captured in the Nemuro Strait. The larga and ribbon seals account for about 90 per cent of all harvest in both areas.

After the drift ice season, only a small number of larga seals remain sedentary along the coast of the Okhotsk Sea and the Nemuro Strait. In recent years the numbers of these seals and their haul out sites have been greatly reduced.

The number of Kuril seals in the Kuril Islands is estimated at about 2,400 animals. In Hokkaido they occur only along the rocky shores of the Pacific coast of eastern part of the island, where they are sedentary all the year round without association with drift ice. The population size and number of haul out (breeding) sites have been reduced by hunting and other causes during the last twenty years, and only 300-350 seals survive in Hokkaido at present.

It is concluded that reduction and extermination of coastal pinnipeds has progressed northwards, from Honshu to Hokkaido in the Japanese Islands.

Summary of the Kuril seal census during the past twelve years

Takeshi SHUKUNOBE Obihiro University of Agriculture and Veterinary Medicine, Obihiro 080, Japan and Tetsuro IToo First Department of Oral Anatomy, School of Dentistry, Asahi

University, Gifu 501-02, Japan

After the warning by the Marine Mammal Research Group in 1973 that the Kuril seal (Phoca vitulina stejnegeri) in Japan was at a crisis of extermination, sixteen censuses were taken to learn the number and status of the seals.

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Fund Japan and twice by the Nippon Life Insurance Foundation.

The censuses were taken at all nine, or some of, the hauling (breeding) grounds scattered

from Nemuro Peninsula to Cape Erimo, in June (breeding season) and August (moulting

season). The method of seal counting was as follows. At each investigation site, one or more

members of the census team observed and recorded, for a week, the number of seals, making

a distinction between those older than one year and pups. The sum total of the maximum

counts recorded at each site, or corrected estimates of them, was used for an estimation of the

population size. In recent years some other types of investigation were added. The censuses

were mainly conducted by the members of five groups, and they amounted to about 350

persons in all.

T he number of seals older than one year at the June census increased from 145-193 in 1974

-1981 to 223-231 in 1982-1983

, as a result of an improved census accuracy. The number of pups

counted increased from 24-40 to 39-53 in the same periods. The total number of seals in

August in 1983-1984 was 344-346, about 50 per cent larger than counts in June. These numbers

were corrected to about 300, excluding a possibility of double counts in two or more sites.

Because NIIzuMA (1985) reported that the number of adult males decreases in June, and that

of females in August, it is too early to estimate an exact population size, but it may be

expected to be about 350 including pups.

There are only three sites having 30 or more seals and 80-90 per cent of population

converged into them. Five sites have only ten seals or so. After the marked decline of

population Moyururi-to Islet and Futatsu-iwa Rocks show no signs of recovery for twelve and

five years respectively. These facts certainly show that present status of the seals is still in

danger in Japan. It is confirmed that the following factors have a harmful effect on seals :

hunting, seals trapped by fishing nets, disturbance to seals by fishing vessels, and blasting

operations of underwater reefs to increase the tangle harvest (stopped at present).

It is to be hoped that the census technique will be improved further to determine the exact

number of seals at Hokake-iwa Rocks, etc., and the identification method should be made the

most of to know the herd composition. The data on migration, emigration, immigration and

mortality are almost entirely in short supply. Apart from the census, the following

investiga-tions need to be carried out : biotelemetry ; determining the cause of extermination at

Moyururi-to Islet, etc. ; and on seal mortality by fisheries.

Socio-ecology of the Kuril seal

Akio NIIzuMA Department of Zoology, Kyoto University, Kyoto 606, Japan

Land-breeding harbour seals, including the Kuril seal, are known to be gregarious

animals. They utilize a •gselected place•h for a resting site, which is called the •ghaul-out site•h,

and they form a remarkable aggregation of a considerable number of individuals on it.

However, little has been considered as to the nature of such a group.

The difficulty in studying social aspects of the haul-out group of seals has probably been

due to the lack of long-term observations as well as the lack of data based on individual

identification in their natural habitat. In recent years, the author has worked out a new

method to record and identify each individual seal on haul-out sites by using photographs.

The pelage pattern (shapes of rings or dots and arrangements of them) is unique to each seal,

and does not change over the years. Thus, this method has made it possible to follow more

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Observations continued since 1975 at a haul-out site of Daikoku Island, eastern Hokkaido, using this method have revealed the following features in the social organisation of the Kuril seal.

Haul-out groups were formed almost every day through all seasons at a strictly fixed place on a rocky reef. However, there were quite different patterns in utilization of the haul-out site between sexes. Adult females occurred only during the breeding season at the site, where they gave birth to pups and nursed them. After the breeding season was over, adult females disappeared until they return in the next breeding season. It is certain that adult females utilize the site primarily as the breeding place.

Adult males, in contrast to females, occurred there rather constantly through the year. It appears that adult males utilize the site for resting. However, there was a remarkable change with season in the frequency of appearance of males. Except for a few, all adult males disappeared in June when adult females showed signs of heat. Scars around the necks of males were observed most frequently in this season. Thus, it is suggested that some kinds of competition occurs among males at this time and only a few males have a chance to access females, although copulation has not yet been observed.

Females showed their typical pattern of haul-out site utilization after 3 to 4 years old, when they probably attained sexual maturity because they would have their first pups in the next year. The younger females haul-out frequently in non-breeding seasons as well as in the breeding season, and the frequency of their appearance increased through their first 3 to 4 years. It is suggested from these records that females become experienced with the site in the years before sexual maturity, and then chose the site for their breeding place.

Males showed their typical pattern of haul-out site utilization after about 5 years old. Mean age of sexual maturity has not yet been determined for males. However, they had the first wounds around their necks after 4 to 5 years old, and play activities were observed only among males which were younger then these ages. These facts suggested that males attained sexual maturity at around 5 years old. Males continued to increase their frequency of appearance at the site until this age, and just before this age they haul-out there most frequently through the year, including June when almost all adult males disappeared.

From this 10-year observation on a haul-out group of the Kuril seals at Daikoku Island, the author has been led to the following speculaiton about the mating system of this seal. Females return every year to a few selected sites for breeding and males can expect when and where their potential mates will gather. This leads to competitive relationships among males around the breeding sites. The Kuril seal clearly does not adopt the harem system which is found in other polygynous pinnipeds like fur seals or elephant seals. Probably, males of the Kuril seal might win dominant status by rather moderate competitive interactions with other members, including play activities and other everyday encounters at and around the site throughout the years and seasons. This is the essential nature of the haul-out group of this seal.

Food and feeding habits of Kuril and Spotted seals captured at the Nemuro Peninsula

Toshiyasu NAKAOKA Obihiro University of Agriculture and Venterinary Medicine, Obihiro 080, Japan, Kazuo WADA Primate Research Institute, Kyoto University, Inuyama 484 Japan, Keiko TANAHASHI Obihiro University of Agriculture and Veterinary Medicine, Obihiro 080,

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Japan and Tsuneyasu HAMANAKA Marine Mammal Research Group, Sapporo 064, Japan Feeding ecology of Kuril seals (Phoca vitulina stejnegei) and Spotted seals (Phoca largha) was studied through the analysis of stomach contents of animals killed in salmon trap nets along the coast of Cape Nosappu of eastern Hokkaido during the period 23 Sept. -1 Dec., 1982 and 16 Sept. -30 Nov., 1983. Two hundred and twenty-nine of 248 Kuril seal stomachs and 83 of 99 Spotted seal stomachs contained identifiable prey remains.

Analysis of stomach contents showed that both seals feed on a variety of taxa and species of fishes. Octopus and 26 species (12 families) of fishes (total= 32 food items) from Kuril seals and octopus, squid, and 19 species (13 families) of fishes (total= 23 items) from Spotted seals were identified.

By frequency of occurrence (F%) and weight (W%), the most important prey species were octopus (62 F% and 51 W% for Kuril seals : 42 F% and 49% for Spotted seals) and saffron cod (33 F% and 3 W% for Kuril seals : 43 F% and 9 W% for Spotted seals). The next most important food items of Kuril and Spotted seals were ribbon pickleback, cresthead flounder, Dybowsky's blenny, and Cottidae sp..

In Kuril seals, important prey species were coastal fishes such as sculpins, picklebacks, and scorpionfishes and migrating fish as salmon (Onchorhncus keta). In contrast to Kuril seals, the diet of Spotted seals is catholic, consisting of coastal fishes such as sculpins, righteye flounders, picklebacks, Pacific sand lance, and surf smelt, and migrating pelagic fishes such as

Pacific saury, true sardine, and chub mackerel.

Otholiths of saffron cod were found in fairly large numbers (310-475 otholiths) from both seals. By using the relationship between otholith size and body size, the back-calculated folk length (FL) was obtained. Fish with FL less than 20 cm were assigned to the 1-year-class which is found at about 20 m depth layer and those with FL over 20 cm to the 2-year-class which is found at about 10 m depth layer. The Spotted seals fed on more 1-year-class fish

(75 %) than 2-year-class (25 %), but in Kuril seals the proportion of 1-year-class (40 %) and 2-year-class (60 %) was not so different, suggesting that Spotted seals are offshore predators as compared with Kuril seals.

The above analysis suggests that feeding activity of Kuril seals takes place in the shallow coastal waters, seeking prey of benthic habit on shore reefs. On the contrary, Spotted seals have their sphere of feeding activity in offshore, on benthic items and pelagic fishes.

Residue characteristics of organochlorines and heavy metals in seals from the coast of eastern Hokkaido

Ryo TATSUKAWA, Masahide KAWANO, Shinsuke TANABE and Katsuhisa HONDA Department of Environment Conservation, Ehime University, Matsuyama 790, Japan

Marine mammals occupaying high trophic levels in the marine ecosystem accumulate persistent organic substances through the food chain. Furthermore, it is known that some heavy metals are distributed and accumulated in target organs and tissues of these animals. It is safe to say that the residues of these chemicals in the mammals reflect the history of pollution in the environment due to their long lives. Thus, marine mammals are suitable for understanding marine pollution by persistent chemicals. In this paper the concentrations and organ distribution characterstics of organochlorines and heavy metals in seals will be present-ed. And also a new approach is attempted to elucidate biological problems of these animals using the persistent chemcals as tracers.

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Three species of seals (Kuril seal, Spotted seal and Ribbon seal) were capered by salmon

trap nets along the coast of Nemuro Peninsula, eastern Hokkaido. Determination of age, sex,

and relevant biometry made in other studies by the Kuril Seal Research Group were used in

this study. Organochlorines (PCBs, DDTs, chlordane compounds, HCHs and HCB) were

determined by GC and GC-MS, and heavy metals were analysed by atomic absorption

spectrophotometry.

The order of concentration for the organochlorines and heavy metals and their

distribu-tion in organs and tissues are generally similar to those in dolphins, porpoises and whales.

When examined in detail, however, we found seal-specific and species-specific (among 3

species) characteristics of these chemicals.

For example, by analysis of PCB isomers and congeners it was found that the

disapperan-ce or decrease of some PCB members in seals is more marked than in dolphins, but is less

marked than in terrestrial mammals and seabirds. Such simplification of PCB components by

metabolic process of animals might correspond with the evolutionary development of the

animals.

A migration model based on sex and age composition of Kuril seals captured

along the coast of Nemuro Peninsula, Hokkaido

Shin-ichi HAYAMA Saitama Cancer Center Research Institute (Present adress : Laboratory of

Wild Animal Medicine, Nippon Veterinary and Zootechinical College, Musashino, Tokyo 180,

Japan, Hiroyuki UNO Department of Applied Zoology, Faculty of Agriculture, Hokkaido

University, Sapporo 060, Japan and Kazuo WADA Primate Research Institute, Kyoto University,

Inuyama 484, Japan

About two hundred Kuril seals (Phoca vitulina stejnegeri) are killed annually in salmon

trap nets along the coast of the Nemuro Peninsula, Hokkaido. They are considered to belong

to the stock of the Habomai Islands and migrate to the coastal area of the Nemuro Peninsula.

A migration model for the Kuril seal in each developmental stage was estimated by the date

of location and the date of capture.

The field work was conducted at Nemuro Peninsula of eastern Hokkaido from 25

September to 1 December, 1982 and from 14 September to 1 December 1983. Ages of collected

animals were estimated by counts of cementum annuli in right upper canine teeth. In this

study, age, sex, location and the date of collection was recorded for 210 Kuril seals. Similar

date on Spotted seals (Phoca largha), an ice breeding type closely related to Kuril seals,

trapped in the same manner, were also used for comparison.

For analysis, the term of the survey was divided into the first half, from 14 September to

20 October, and the second half, 21 October to 1 December.

Kuril seals were trapped throughout the term of the survey, but differences were found

between the first half and the second half in the area of capture and age composition. In the

first half, pup class (0 year old), immature class (1-2 year olds) and subadult class (3•`5 year

olds) were trapped around at Cape Nosappu (the nearest to breeding sites, Habomai Islands).

On the other hand, in the second half, Kuril seals were trapped all around the Nemuro

Peninsula, but the proportion of animals trapped around the Cape decreased. Adult female

class (6•`10 year olds) and old female class (11 year olds and over) were also trapped in this

period, but adult male class were hardly trapped. Almost all the animals of adult and old class

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second half of survery, and there were differences in age and sex composition from the case of Kuril seals ; pup-, immature- and old class of both sexes were trapped.

By direct observation of the Kuril seal at Daikoku Island, Hokkaido, NIIZUMA (1985) demonstrated that adult males hardly leave the breeding site during the non-breeding season. The conclusion in this study supports Niizuma's observation.

Comparison of cranial growth and development beteeen Kuril and Largha seals

Hiroyuki UNO Department of Applied Zoology, Faculty of Agriculture, Hokkaido University, Sappro 060, Japan

One hundred and twelve skulls of the Kuril seal (Phoca vitulina stejnegeri) and 73 of the Largha seal (Phoca largha) were investigated to compare the patterns of growth and develop-ment between them. Age was determined by counting the growth layer in the cedevelop-mentum of canine teeth. Age classes were divided accoring to postnatal development stage into three : pups (0 year), subadults (1-4) and adults (more than 5 years). Condylobasal length, cranium weigth and mandible weight of adult males were larger than those of adult females in Kuril seals, while there were no sexual differences in these characters in Largha seals. Kuril seals had larger skulls which had further advanced in developmental stage than those of Largha seals. Especially, the relative sizes of the palatal parts were much larger in pups of the former than in those of the latter. This finding suggests that there are some differences between the two species in the development of the masticatory musculature and also in the behaviour at the pup stage. The interspcific variations shown above might occur both in the foetal and maturing stages.

Sexual maturity and developmental stage of Kuril seals

Masatsugu SUZUKI and Tadayuki YAMASHITA Department of Veterinary Anatomy, Obihiro University of Agriculture and Veterinary Medicine, Obihiro 080, Japan

We divided growth processes of Kuril seals into developmental stages by using the development of their reproductive organs as a criterion. Materials were obrained from seals drowned in the autumn season salmon trap nets along the coast of Nemuro Peninsula in 1982, 1983 and 1984.

In males, weight of testis, length of baculum, diameter of seminiferous tubules and histological condition of seminiferous epithelium were examined. Male reproductive organs showed gradual growth during 0-2 years and resumed growth after 4^-5 years, following a stagnation between 2 and 4 years. The process of sperm formation from spermatids was observed in only one animal of 4 years (N = 9) but all of 5 years (N = 4). Thus, it seems that spermatogenesis begins at 4 or 5 years. Hence we divided growth of male Kuril seals into the following four developmental stages : (1) early juvenile ; 0-1 years, (2) later juvenile : 2-3 years, (3) adolescent : 4 years, (4) adult : 5 years and older. According to NAITO and NISHIWAKI (1972), growth of male body length continues until 9 or 10 years ; animals between 5 and 10 years should properly be called "young adult".

In females, presence of corpus luteum and corpus albicans in ovaries and presence of fetuses were examined. We regarded animals which had a corpus luteum but not a corpus albicans in their ovaries, as animals which had ovulated for the first time, and those which did not have fetuses as non-pregnant animals. We have already confirmed that the corpus

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albicans remains for a long time and implantation takes place before the sampling season (HAYAMA et al. in prep.). Macroscopic and microscopic observations on ovaries indicated that first ovulation occurs at 3 or 4 years in many animals, with a few cases at 2, 5 or 6 years. Fifty per cent of first ovulated animals (N =12) were pregnant. The youngest pregnant animal was 2 years, and pregnancy rates were 23.5 % (N =17), 50 % (N = 8), 75 % (N = 4) and 90.5 % (N = 21) in 3, 4, 5 and 6 years and older, respecitively. Hence it is suggested that first pregnancy takes place about 4 years in many animals. Thus we divided growth of female Kuril seals into the following three developmental stages : (1) juvenile : 0-1 years, (2) adolescent : 2-3 years, (3) adult : 4 years and older.

The growth curve of body length of males showed an acceleration with preceding deceleration at 4 to 5-years-old, when they were attaining sexual maturity. This tendency is similar to other polygynous and harem establishing seals, such as grey and elephant seals. So, this supports the theories that Kuril seals may be polygynous (NIIzuMA, 1983) and adult male animals probably fight with each other in the breeding season (NAITO, 1973).

Population gentics of Kuril seals

Yoshihisa Fu1IO and Yuhko SAITO Faculty of Agriculture, Tohoku University, Sendai 980, Japan

Starch gel electrophoresis was carried out to estimate the amount of genetic variability and degree of genetic differentiation in seals. Four species of seal were used for this work ; they were Phoca vitulina stejnegeri, P. largha, P. fasciata, and Erignathus barbatus. Some years ago, P. vitulina stejnegeri had been classified as a variety of P. largha. The proportion of polymorphic loci varied from 0.029 to 0.147 and heterozygosity over 34 genetic loci varied from 0.010 to 0.052. These values are similar to those obtained from large mammals and smaller than those obtained from small mammals. The genetic distance (NEI,1972) between P. vitulina stejnegeri and P. largha was 0.0165, between both P. vitulina stejnegeri and P, largha from P. fasciata was an average value of 0.0631, and between the three species and Erignathus barbatus was an average value of 0.2332. This indicates that the degree of genetic differentiation is small compared to rodents.

The developmental change and sexual dimorphism of the Kuril seal

Sin-ichi HAYAMA Saitama Cancer Center Research Institute (Present adress : Labortory of Wild Animal Medicine, Nippon Veterinary and Zootechinical College, Musashino, Tokyo 180, Japan)

The Kuril seal (Phoca vitulina stejnegeri), a land breeding harbour seal, is considered to have evolved from an ancestor that would probably be the Spotted seal (Phoca largha), an ice breeding harbour seal. The purpose of this study is to make clear what developmental changes of the Kuril seal have occurred in adaptation to the new niche.

The degree of sexual dimorphism of the Kuril seal is larger than that of the Spotted seal, and this fact is considered to be related to polygynous social structure of the Kuril seal. The breeding habit of the Kuril seal is examined throught the comparison with sexual dimorphism in other pinnipeds.

Two hundred and two specimens of Kuril seals (104 males and 98 females) and 78 of Spotted seals (43 males and 35 females) captured in salmon trap nets in adjacent waters of Nemuro Peninsula, Hokkaido, were used in this study. The following measurements were

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taken from the animals : standard length, head length, front flipper length, hind flipper length, axillary girth. Thses measurements were taken after skinning. Ages of collected animals were estimated by counts of cementum annuli of right upper canine teeth.

The allometry of external characters to the standard length was computed in both species. The relative growth of the axilliary girth to the standard length was positive and the growth of the other was negative. The growth of head length was accelerated in the Kuril seal, and this was considered to be related to the standard length, the male Kuril seal was larger than spotted seal. In size of hind flipper length to the standard length, the female Kuril seal was smaller than the spotted seal. It is suggested that these characters are adaptive to their habitat, considering their swimming behaviour and life history.

Under the hypothesis that the degree of sexual dimorphism in pinnipeds is addected by their harem size, the relation of harem size to the logarithmic proportion of male body weight to females was examined in various species. There was a significant relation between these, and this suggests that the number of breeding females to one harem bull is 4-5 in the Kuril seal.

Rearing and care of orphan Kuril seal and their reintroduction into nature

Takashi SUMIYOSHI, Kushiro Municipal Zoo, Akan-cho, Hokkaido 085-01, Japan

Nine orphan pups of Kuril seals have been reared in Kushiro Municipal Zoo since its foundation in 1975. From our experience with these animals, the best care for the pups is feeding them with ground fish once or twice, to condition them to captive feeding, thereafter rearing them on whole fish. This finding has led to the result that Kuril seals show a better rate of survival in artifical conditions than other seals.

Most of these Kuril seals reared in captivity are being used to make a breeding colony under the condition of captivity. We do not expect that these seals will find much difficulty if they are reintroduced into natural habitat. The obstacle to an attempt of this sort would be, rather, how the social consensus can be reached among the different, conflicting human interests around the area of reintroduction.

c : Relations between coastal fisheries and pinnipeds

On the interactions between Kuril seals and salmon trap net fisheries along the coastal waters of south-eastern Hokkaido

Kazuo WADA Primate Research Institute, Kyoto University, Inuyama 484, Japan, Sin-ichi HAYAMA Saitama Cancer Center Research Institute (Present actress : Laboratory of Wild Animal Medicine, Nippon Veterinary and Zootechnical College, Musashino, Tokyo 180, Japan), Toshiyasu NAKAOKA Obihiro University of Agriculture and Veterinary Medicine, Obihiro 080, Japan, Hiroyuki UNO Department of Applied Zoology, Faculty of Agriculture, Hokkaido University, Sapporo 060, Japan and Kenji SHIMAZAKI Research Institute of North Pacific Fisheries, Hokkaido University, Hakodate 040, Japan

Abuot two hundred Kuril seals are annually found dead in Salmon trap nets along the coastal waters of the Nemuro Peninsula and adjacent areas. Although dead Kuril seals were collected over dispersed areas, the trap net of Habomai Fishermen's Co-operative Association (FCA) captured 273 seals, 83.7 % of toral number of dead seals, and orther four FCA varying

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from 8 (2.5 %) to 18 (5.5 %).

Kuril seals amount to 71.4 % of the total pinniped kill in the fishing gears ; Largha seals

25.3 %, and the rest are Ribbon seals, Ringed seals, Bearded seals and Northern fur seals.

While Kuril seals are captured throughout the fishing period of salmon trap nets, Largha seals

and other kinds of pinniped are confined to the latter half of the period.

In the area of Habomai FCA, net No. 27 located nearest to Nosappu Cape has the largest

proportion of the seal mortality (38.0 %). Cases of seal death decrease as the nets are located

farther apart from the Cape : No. 28 (18.4 %), No. 26 (9.0 %), No. 25 (9.8 %). From this fact,

it is suggested that the dead Kuril seals came from the Habomai Islands of the USSR.

Detailed observation of salmon damage by seals was made in salmon trap net NO. 27 of

Habomai FCA. Damage consisted of salmon head remains, dead salmon, and those with scars.

Salmon heads were found mainly in the bag nets D and E (95.8 % of the head remains) in 1982,

and B, D and E (84.0 %) in 1983. Two bag nets A and B, farthest from the coast, were set on

the sea bottom at 38 m deep ; the middle two (C and D) at 10 m ; and the nearest to the coast

(E) at 7 m. From this fact, Kuril seals would seem to prefer shallow sea waters.

Sharply cut scars on the body surface at salmon which were observed on the floor of fish

market are considered to be made by the claws of seals. 41 % of the scarred salmon had scars

on both sides and the rest on a single side. It seems that the former was caused by the seal's

mouth. These salmon scars were found throughout the fishing period and had no relation to

the actual catch of seals. This means that Kuril seals could easily escape from the trap net

after scarring salmon.

No relationship was found between the daily salmon catch and the number of seals found

dead and between the latter and salmon head remains.

In the trap nets in Habomai FCA, other than No. 27, damage to salmon does exist though

it is comparatively small. Damage to the salmon by seals, inculuding scarring and head

remains, comprised 4.6 % of the total catch. If the catch increases, the proportion of damage

may decrease.

Estimation of damage by Kuril seals to a salmon trap net fishery

neighbouring with a haul-out site of Daikoku Island

Akio NuzuMA Department of Zoology, Faculty of Science, Kyoto University, Kyoto 606, Japan

All salmon and seals caught by the Daikoku salmon trap net on 18-23 June, 1984, were

examined. In order to estimate the degree of damage to salmon catches by seals, records of

the number of salmon with and without wounds in total catches of the net were analysed

statistically for this and for the previous seasons.

The Daikoku salmon trap net was located about 1,300 m east of Daikoku Island, one of

the largest-out and breeding sites of the Kuril seal along the Pacific coast of Hokkaido. The

net was made up of a •gwall•h (•gleading•h) net 1,800 m long and of four trap-nets, arranged at

both sides of the far end and about the center of the •gwall•h. The upper surface of each

trap-nep was about 10.5 m below the sea surface. The net was set twice a year in spring and

autumn : from early May to late July for dog salmon (Oncorhynchus keta), chinock salmon (0.

tschawytscha) and other speices of salmon ; and from early September to late November for

dog salmon.

All the damage to salmon examined during the investigation consisted of wounds on the

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trap-net and active as healthy ones. Severe damage to salmon (heads removed from the body by seals, for example) were not recorded during the investigation ; however, an owner of the net claimed that such damage occurred rather frquently. Seals did not cause any damage to the net itself.

The percentage of salmon with wounds in total catches among season : 3.2 % (79 in 2,460) for the spring season of 1984, 1.9 % (36 in 12,460) for the spring season of 1983 and 2.1 % (613 in 29,497) for the autmn season of 1983. However, the differences in rate between the season were not statistically significant (R X C test). Also, no significant differences were found among any months in each season and among salmon species by the same test.

During the spring season of 1984, fourteen seals were killed in the Daikoku salmon trap net. A corresponding increase of damage to salmon was not found for days when seals were found in the net. Only two of these 14 seals were Kuril seals, the rest were other species (10 Largha seals, l Ribbon seal and 1 northern fur seal) which lived mainly in the Okhotsk Sea. All 14 seals (except one Ribbon seal) were pups, which certainly could not eat live salmon. In fact, the stomachs of four seals examined contained no fragments of salmon nor of other fishes.

In conclusion, whether damage to salmon was caused by Kuril seals or by other species of seals (including the Steller sea lion and northern fur seal) has not yet been clarified. Also, when and where salmon get wounds on the body poses a new question to be studied.

Estimation of damage by Kuril seals to salmon trap net fisferies at Cape Eromo

Keiko TANAHASHI Obihiro University of Agriculture and Veterinary Medicine, Obihiro 080, Japan

Cape Erimo is the largest breeding area in Japan for Kuril seals. It is also the most important place biologically for seals at the southernmost point of their distribution in Japan as well as at the western edge of the Pacific Ocean. The Kuril Seal Research Group investigat-ed the losses of fisheries through seal damage to salmon caught in trap nets along the coast of Cape Erimo. From the period 11 September to 22 November 1984 we investigated mainly the three trap nets No. 9 (Maruko), No. 8 (Marukome), and No. 7 (Maruho), along the eastern side of Cape Erimo. Salmon catches were brought to the market of the Erimo Fishermen's Association and weighed. We computed the degree of damaged salmon from all those caught and investigated the kind, degree and position of injury to the salmon. Severely damaged salmon were almost all thrown bsck into the sea by fishermen. Trap nets around Erimo are not down on the bottom of the sea but are at sea level so that seals rarely die.

We found the following seven points during our investigations.

1) Injuries to salmon were divided into fresh injuries, those nearly healed and healed. 2) The fishing season is divided into two periods besed on the haul of salmon from the three trap nets.

3) The proportion of damaged salmon to total catches in each of the three trap nets was 1.31 %, 1.67 %,1.37 % for No. 9, 8 and 7 respectively.

4) In the latter period in No. 9 trap net, at the peak of the haul, the proportion of damaged salmon was down, and when the haul was down the degree of damage was up.

5) The value of damaged salmon was 70 % to 80 % of the value of normal salmon. 6) Damaged salmon appeared in all places of the association that we recorded. But injury

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to salmon was not really caused by seals at the Samani and Fuyushima Associations. 7) Further research is needed to determine the location where damage occurs and the nature of the predator.

Migration of Steller sea lion and their damage to fisheries along the Hokkaido coast, Japan

Masami YAMANAKA Research Institute of North Pacific Fisheries, Hokkaido University, Hakodate 040, Japan, Noriyuki OHTAISHI Department of Anatomy, School of Dentistry, Hokkaido University, Sapporo 060, Japan and Tetsuro IToo First Department of Oral Anatomy, School of Dentistry, Asahi University, Gifu 501-02 Japan

Based on the information obtained from fishermen and hunters in Hokkaido from 1981 to 1985, the results of our ecological survery from 1981 to 1983 and the records of the annual damge to commercial fisheries by sea lions collected by Department of Fisheries of the Hokkaido Goverment, migration of the Steller sea lion (Eumetopias jubatus) and interaction between sea lions and commercial fisheries were studied.

Sea lions migrating to Japanese coast from winter to spring are divided into two stocks, the so-called stocks of the Sea of Japan (S. J.) and of the Shiretoko-Pacific (S. P.). The former appeared to come from the Sakhalin coast and the latter from the Kuril Islands. Most of the individuals in the S. J. stock stayed in the coastal waters of Rebun and Rishiri Islands and Sarufutsu district during winter, though some of the stock migrated to the Shakotan Penin-sula, south-western Hokkaido. The S. P, stock was abundant along the east coast of the Shiretoko Peninsula during winter, but a part of the stock migrated down to Cape Esan, rarely to the Aomori district. It should be noticed that remarkable difference in sex ratio and age comosition were recongised in each area during their migration. A possble consideration was that they had peculiar patterns of migration according to sex and age class.

In recent years, reduction of the distribution and decrease in the number were found in the south area. Hauling ground of sea lion have decresed remarkably all over Hokkaido.

Since interactions between commercial fisferies and sea lions occur frequently along the Hokkaido coast, the problem of damage remains important for fishermen especially along the coasts of Rebun and Rishiri Island and the Shakotan Peninsula. In these areas, the damage is mainly against bottom gill nets and bottom set nets. The damage was divided roughly into three categories : breakdown of fishing gear, taking fish that have been caught by the net and dispersing shoals of fish. Conflicts between commercial fisheries and sea lions have been an important problem for many years, but some of their actual circumstances have not been know sufficiently.

An economic estimation of damage to the salmon trap net fishery by seal Hiroshi MASUDA Faculty of Fishery, Hokkaido University, Hakodate 040, Japan

1. Fishing rights for trap nets are renewed every five year. The yield of the salmon trap net fishery has been subject to sharp fluctuations and economic instability. From the fifth renewal of the rights in 1974 the yield of salmon became stable, and people desiring to share the fishing rights of salmon trap nets increased. Consequently, the form of participation for the fishing rights is designed by each coastal fishery co-operative.

The fishing rights of trap nets in the Habomai coastal fishery co-operative unit is owned by the co-operative association and each trap net is managed by the fishermen who desire to

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participate. Each fisherman has a share in gains in proportion to the degree of contribution in the joint enterprise. So, the economic reality of the damage by seals on the trap net fishery is the deduction in the total profit of the joint enterprise. However, the amount of total damage is liable to be compared with the amount of the shares of individual members,

especially by fishermen with small holdings.

2. The damage by seals may consist of (1) the influence on salmon to migrate and get into the net, (2) the damage to the net itself, and (3) feeding on salmon and salmon impairment. For the first point, no data exist to support such influence. Secondly, there are not many cases of net damage. Finally, the census and other data indicate that the total damage amounts to two or four person's share of the gain of the joint enterprise.

d : Special lectures by invited scientists

Lifetime reproductive success in Northern elephant seals

Burney J. LE BoEUF Department of Biology and Coastal Marine Studies, University of California, Santa Cruz, California. 95064, U. S. A.

Lifetime reproductive success (LRS) was estimated in samples of 138 male and 204 female northern elephant seals, Mirounga angustirostris, marked at birth on Aro Nuevo Island, California. The estimate for males was based on number of copulations with different females ; the estimate for females was number of pups weaned in a healthy condition. Males began competing to mate at age 5 and achieved peak suuccess at age 9-12. Females gave birth for the first time at age 2-6 with 4 being the mean age. Fecundity was high (97 %) in females of all ages but females 6 years of age and older were more successful in weaning their pups than females 5 years old or less. Males showed great variability in LRS. Only 8.8 % of the sample mated but some males were very successful, inseminating as many as 121 females. Thirty three percent of the females samaple mated. Most breeding females weaned 1-3 pups in thrir lifetimes ; a few females weaned as many as 10 pups. The most important component of LRS in males is the number of offspring sired. Access to mates is determined by living to maturity and achieving high social rank among males competing in a large harem. Large size is one of several factors important in fighting and achieving high social rank. Important components of LRS in females are lifespan and rearing pups successfully. In surviving females, variables associated with advancing maturity-size, dominance and maternal experience-facilitate nourishing, protecting and weaning pups. Breeding succes in male elephant seals is much more variable than in females, a sex difference found in other polygynous mammals like red deer, and predicted by sexual selection theory.

Harbor seals of the Aleutian Ridge

John J. BURNS Alaska Department of Fish and Game, 1300 College Road, Fairbanks, AK 99701, U. S. A.

Harbor seals, Phoca vitulina, of the Aleutian Ridge and Pribilof Islands were studied through field observation and examination of animals (173 seals, 15 fetuses) collected in four areas : The Commander, western Aleutian, eastern Aleutian, and Pribilof Islands. Spotted esals, Phoca largha, were not analyzed in this study. Habitats were similar in these four areas and seals were present at all locations visited. Defferences in pelagecoloration between seals of the Aleutian and Commander Islands were not significant, but there was a trend toward

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more dark colored seals in the western islands. Growth in relation to age of seals from four area was similar, as was fetal growth. Mating was found to occur in July to early August, implantation in November, birth in early June to July, and weaning of pups by mid-August. Some females (33 %) first ovulated at age 3. First pregnancy also occured in some 3-year-olds, all females had been or were pregnant by age 6. The incidence of pregnancy in sexually mature animals was 75 %. Similarities among seals of the Aleutian Ridge include timing of events in the reproductive cycle, size/age relationships including fetal growth, food habits, and habitat utilization. Harbor seals of the North Pacific region vary in size and coloration in an apparently clinal manner over their linearly continuous range from Mexico to Japan.

We reexamined the taxonomic status of the geronimensis, richardsi, and stejnegeri forms of harbor seals, Phoca vitulina, in the North Pacific Ocean by comparing the cranial differentiation among them with the differentiation of P. vitulina from its sibling species P. largha, the spotted seal. This assesment was based primarily on the results of three di-scriminant analyses and a Q-mode analysis, for which we used both measurements and nonmetrical characters of skulls. The results showed that the differentiation of vitulina from largha is greater than that among the three Pacific forms of vitulina. Within vitulina, the geronimensis form in southern California and Mexico is not clearly differentiation from richardsi. The stejnegeri form, conversely, has becom differentiated sufficiently for subspecific status. The "boundary" between stejnegeri and richardsi is not in Near Strait as proposed earlier, instead, it seems to be in the vicinity of the eastern Aleutian Islands and Alaska Peninsula. A firm conclusion on that point cannot be reached, however, without study of additional specimens from that region.

The grey seal in the United Kingdom

W. Nigel BoNNER British Antarctic Survery, Natural Environment Research Council, High Cross, Madingley Road, Cambridge, CB3 OET, United Kingdom and John HARwooD Sea Mammal Research Unit, Natural Environment Research Council (adress as above)

Grey seals (Halichoerus grypus) are, on a world-wide scale, comparatively uncommon, with a total population estimated at about 150,000. Of these, about 84,000 are found in Great Britain, with the highest concentrations on islands off the north and west of Scotland.

Like Kuril seals, Grey seals show sexual dimorphism, males weighing on avereage about 233 Kg while females are only about two-thirds of that. Females come on land to produce their pups in autum (September to December) and there is substantial polygyny, a very few active males accounting for a large proportion of all copulations.

Grey seals feed on a wide variety of fish (including commercially fished species), crustacea and molluscs (chiefly squid and octopus).

Grey seals were hunted by prehistoric man, probably mostly on their island breeding grounds. Subsistence hunting of this type continued until the present century. Small farmer-fishermen took seals for oil, hides and meat for bait. Changes in the pattern of agriculture led to a decrease in the number of small farmers, and the abandonment of many off-shore islands. Grey seals, whose populations in Britain had probably been regulated by this type of hunting, and which had declined to low numbers at the beginning of this century, were able to find safe breeding grounds on abandoned islands and to start an increase in numbers which is still continuing.

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The first legislation on Grey seals in the United Kingdom, dating from 1914, was designed to protect what was then considered to be an endangered species. This was done by prohibiting the killing of seals during their breeding season. Later legislation took account of the greatly increased number of seals and, while affording protection, also allowed the killing

of seals for management purposes.

Complaints about the damage caused by increasing number of grey seals from fishermen, and particularly salmon fishermen, led to the setting up of an official committee which recommended in 1962 that seal numbers should be reduced by killing part of the pup crop each year. The initial quotas were inadequate to achieve the stated objectives and seal numbers continued to rise. In 1977 the Department of Agriculture and Fisheries for Scotland (DAFS) estimated that Grey seals were consuming 65,000 tonnes of fish a year, and concluded that this was causing insupportable damage to Scottish fisheries. As a result of this report a cull was instituted that was planned to take 900 breeding female seals and their pups, together with 4,000 weaned pups, in each of the six years 1977-1982. The first year of the programme resulted in a total kill of only about 600 seals.

Following widespread public concern, the plan to kill adult seals was abandoned and hunting was restricted to the taking of a small annual quota of pups. Seal numbers continue to rise.

A recent report prepared for DAFS by Sea Mammal Research Unit indicates that by 1981 the British Grey seal population was consuming 84,000-215,000 tonnes of fish per year. However, a significant proportion of these fish were of low commercial value or were eaten in areas where fishing effort was low. On the basis of this evidence it has been difficult to justify a large-scale cull of Grey seals to protect fisheries interests. Nevertheless, Grey seals do have a significant impact on local fisheries-particularly those for salmon-and devices to scare seals away from nets are now being developed and tested.

e : Coexistence of fisheries and marine mammals-Economical, legal, administrative and other special conditions for the protection of Kuril seal

Process and some problems on the protection of Kuril seals during the past eleven years

Masatsugu SuzuKI Department of Veterinary Anatomy, Obihiro University of Agriculture and Veterinary Medicine, Obihiro 080, Japan.

Since 1973, intensive researches on Kuril seals including census survey along the coast of eastern Hokkaido, have been carried out, along with the protection movement by the Marine

Mammal Research Group of Mammal Research Association (MMRG) and the Kuril Seal Research Group (KSRG) of Obihiro University of Agriculture and Veterinary Medicine and Hokkaido University.

I will describe here the history and present status of the protection of the seals and discuss some of the problems :

(1) Damage to Fishery : Recent studies showed that damage to fisheries, especially to the salmon trap net fishery, was restricted to certain trap net stations. In other words, the damage varied from station to station, so that we have to protect the animals and estimate the cost of the damage with due regard to the local socio-economic conditions. In addition, we have to establish a resonable definition of •gdamage by seals•h.

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(2) Population size to be maintained : The protection or conservation of wildlife is closely

related to the conflict between the increasing size of the animal population and the rights of

local people (the fisherman, in this case).

It is difficult, in fact, to determine an ecologically resonable population size for Kuril

seals. However, many fishermen are anxious about an increase of damage caused by

increas-ing seals. Thus, a suitable protection and management plan should include the consideration

of environmental capacity of the seal, and the balance between the feelings of the fishermen

and the prosperity of the seals.

(3) Conservation Group and Fishermen : In the past, there was a lack of mutual

under-standing between conservation group and the fishermen. Although the communication

between them shows signs of improvement, some fishermen strongly assert that •gprotection of

seals•h is not compatible with their salmon fishery. This suggest that the group and the

fishermen have yet to gain mutual understanding.

(4) Protection movement and its method : Our research on seal damage to the fishery has

been supported by several private foundations. However, we would like to say that the

Japanese Goverment should make the assessment of the damage to the fishery or cover the

expense, at least, because this species has already been on the administrative process toward

its designation as a precious natural product of Japan. In addition, both the protection group

and the fishermen have never put any claim on delay to the administration. This passive

attitude has led to the sluggish response of the administative authorities.

Some remarks on the designation of Kuril seals

as a precious natural product of Japan

Masaaki YoNEDA Japan Wildlife Research Center, Tokyo 113, Japan

For nature conservation and wildlife management in Japan, there are six important laws

(acts) as follows :

1. Nature Park Law

2. Nature Conservation Law

3. The law concerning wildlife protection and hunting

4. The law for the protection of cultural properties

5. The law for the protection of aquatic resource

6. Others (International Treaties, etc.)

(1) National Park Law and Nature Conservation Law

These two laws deal with land zoning for nature parks (National Parks and

Quasi-National Parks) and nature conservation areas. The total area of nature parks amounts to

53000 sq km and covers 14.1 % of the whole of Japan. There are 10 aquatic national parks

where some aquatic animals (mainly tropical fishes) are protected. However, aquatic

mammals are not yet included in the protected animals in these aquatic national parks. The

Nature Conservation Law was enacted for the purpose of attaining systematic conservation

and preservation of the natural environment in Japan. The nature conservation areas, which

are more strictly controlled than national parks, amount only to 970 sq km (0.2 % of the area

of whole of Japan).

(2) The Law Concerning Wildlife Protection and Hunting

Although this law stipulates promotion of agriculture, forestry and fisheries through

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wildlife as renewable nature resources. Wildlife protection areas cover 31000 sq km (8.2 % of

the area of Japan) including 3700 sq km protection area of water surface. The law has

traditionally dealt with land animals and birds including water birds, and the aquatic animals

are under the control of the law for the Protection of Aquatic Resources. However, the

Fishery Agency of Japan does not deal with the Kuril seal as an economic aquatic resource.

(3) The Law for the Protection of Cultural Properties

This law was enacted to preserve cultural properties and to make efficient use of them.

Endemic species and the species of 'high scientific value' are designated as natural monuments

by the Government. The law is the effective measure in Japan to protect the endangered

species.

(4) Other Laws (Acts) and International Treaties

If the Japanese government continues to carry out a 'laissez-faire' policy of fisheries

around the breeding sites of the Kuril seal, it is very likely to lose this species for ever from

Japan. The extermination of this seal would inflict a great loss on the conservation of the gene

pool and species diversity in Japan. The author thinks that the Kuril seal should be managed

as an aquatic living resource under the Law for the protection of aquatic resources. But,

because the Fishery Agency dose not regard the seal as a resource, we should aim at the

drawing up of an international seals conservation treaty or the realisation of an endangered

species act in Japan.

Legal and administrative problems in the conservation of pinnipeds

Ritsuo YosHI-IKE Marine Mammal Research Group, Sapporo 063, Japan

Problems deirectly concerning Kuril seals will be discussed here. The fishery damage

problem stands in the way of the realization of necessary conservation measures for this

species. Since damage is a many-sided, complex phenomenon, comment will be made from

several different points of view.

(1) Biological : Comments have already been made in several proceeding papers. In the

food web of nature, if the species preyed upon is a commercially valuable species, damage

problems can occur.

(2) Administrative : When, and only when, the above relationship is posed against

government administration and •gsocialized•h through the appeal by those who suffer the

damage, it can make a social problem.

(3) Economic : Several problems from the aspect of fishery economics have been pointed

out in this symposium. When biological damage exceeds a certain critical level, it will cause

economic damage, in relation to the circulation organisation of fishery product.

(4) Emotional: Even if damage is economically negligible, by exceeding a certain

emotionally limited level with relation to fishing catch and biological damage volume, it will

give remarkable pressure or uneasiness to fishermen. This type of emotional level of damage

drastically changes according to economical, legal, administrative faithlessness or

dissatisfac-tion.

Kuril seals apparently cause damage to Salmon in the locally limited areas of the salmon

trap net fishery. For solving the damage problem, the fishermen concerned have to demand

that the national and prefectural administration take measures to control the damage. In the

meantime, as a way to the conservation of Kuril seals, their designation as a natural

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conservation should be enacted. As a necessary part of the conservation measures, in the administration channel, ways to solve the damage problems will be examined. These must include development and application of techniques to control biological damage, and adminis-trative and fishery-economical solutions both outside and within the fishery management concerned with the damage.

A plan for the future of protection of Kuril seals

Keiko TANAHASHI Obihiro University of Agriculture and Veterinary Medicine, Obihiro 080, Japan

In 1973, the Marine Mammal Research Group asked the special government agencies concerned that the Kuril seal should receive protection measures because of its substantial decline in Japan. In December 1974, the Cultural Properties Protection Committee proposed to the Agency for Cultural Affairs that the Kuril seal deserves the status of a precious natural product. However, the Agency for Cultural Affairs has made no progress in coordination with the local people, primarily fishermen, and no agreement has been reached with them to enforce the designation. Thus the Kuril seal is not a protected species yet. The reason was the following four conditions put forward by the fishery association which were unaceptable both to the Marine Mammal Research Group and to the Agency for Cultural Affairs.

(1) There can be culling when seals increase too much.

(2) Fishermen can fire to threaten seals coming near fish nets. Even if a seal is killed by mistake, the shooter will not be punished.

(3) Off-shore submerging rocks and reefs can be blown up.

(4) When fishermen suffer damage, compensation for those damage will be available from the government.

The aim of this report is to propose a system of necessary conservation or proper management of the Kuril seals by the Culture Properties Protection Law, or some other law. Designating seals as a precious natural product could have two significations, though it would not provide the full measures to protect them.

First, it would give seals legal support. They have been left outside the sphere of the hunting and fishing regulations because they are mammals living in the sea, and have little commercial value. The Kuril seals have been totally neglected and have every chance of becoming extinct as did the Japanese sea lions.

Second, it would be helpful in financial support for the investigations necessary for their conservation. We think the government should pay for this.

To conserve Kuril seals practically, the following six clauses are necessary.

(1) The number of the seals seems to be stable (about 350) because census returns have not varied much for the last eleven years. The present population size should be maintained at least.

(2) There are six sites where seals haul-out, and two sites where the seals had hauled out until several years before. Destruction of these area should be prohibited.

(3) Catching seals must be prohibited. When a seal is captured in a fish net, the management authority should be noticed (see 6). The authority would examine the carcass and performs investigations for the purpose of scientific management.

(4) Culling of seals : the management authority judges whether culling should be perfor-med. Before the Culling, birth rate, mortality rate, movement among the haul-out sites, and

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