Wflal~erv:-c;rrc.

The Northern Seal ~/ /

U IS, S, R, /

/

Breeding grounds of the northern fur seals: Robben (Kaihyoto or Tyuleniy Island) off ; the Commandel ( and Medny or Copper Island) at the Soviet end of the Aleutian chain; and the - St. Paul Island, St. George Island, Island, Island, and Sea Rock.

Cover - The Pribilof Islands in are the homeland of the largest fur eal herd in the world. Here the fur seals come ashore to their young on the rocks and sands above tidewater. The story behind the restoration and de­ velopment of the Ala ka fur cal herd is one of adventure and international diplomac}. It i a heartening account of cooperation among nations - an out- tanding example of wildlife conservation. DEPARTMENT OF THE INTERIOR Walter J. Hickel, Secretary Leslie L. Glasgow, Assistant Secretary f01' Fish and Wildlife, PaTks, and Marine Resources Charles H , Meacham, Commissioner, U,S, FISH AND WILDLIFE SERVICE Philip M, Roedel, Di1'ecto1', BUREAU OF COMMERCIAL

The Northern By RALPH C. BAKER, FORD WILKE, and C. HOWARD BALTZ02

Circular 336

Washington, D.C. April 1970 As the Nation's principal conservation agency, the Department of the Interior has basic responsibilities for water, fish, wildlife, mineral, land, park, and recreational resources. Indian and Territorial affairs are other major concerns of America's " Department of Natural Resources." The Department works to assure the wisest choice in managing all our resources so each will make its full contribution to a better United States - now and in the future. CONTENTS Page Early history of fur sealing ...... 2 Distribution and movement of seals ...... 4 Food ...... 9 Physical characteristics ...... 9 Reproduction ...... 10 Mortality and disease ...... 12 Population ...... 13 Management ...... 14 Research ...... 16 Sealing on the Pribilof Islands ...... 17 Processing and sale of fur seal skins ., ...... 18

iii The '

By RALPH C. BAKER, FORD WILKE, and C. HOWARD BALTZO'

ABSTRACT The early history of worldwide fur sealing; the distribution and movement of north­ ern fur seals; and their food, physical characteristics, reproduction, and mortality and disease are discussed. Information is also given on fur seal population, management, and research; sealing on the Pribilof Islands; and processing and sale of fur seal skins.

The northern fur seal was first described from November to May when they begI by in 1742, and the turning to the rookery islands. The largest part of the population was found on seals return first. the Pribilof Islands by Gerassim Pribilof in Fur seals feed on anchovy, hake 1786. The number of fur seals reached its , , miscellan lowest level, about 216,000, in 1911 after per­ fish, and . They feed effecti el r iods of mismanagement by and the Their fur is waterproof. 1'a p United States and the attrition from pelagic tained more than one year. sealing. The Convention of 1911, signed by Male seals acquire harems her Canada, Japan, Russia, and the United States, years old. Females have their firs and the succeeding Convention signed in 1957, 5 or 6 years old after a year-Ion gave protection needed for recovery. Pop­ Pups are fed every 5 to 14 da) s ulations are now near maximum on the Prib­ a fat content of 50 percent. T ilof Islands and Robben Island and are in­ to swim from birth. creasing on the . Seals Malnutrition, hookworm infer became reestablished on the in and bacterial infections kill :5 t the 1950's. They reappeared on San Miguel of the pups on land, depending on Island, Calif., in 1968. density. Others die at sea, WIth 15 Fur seals migrate south to waters off cent surviving to age 3. southern and northern Japan. Seals The number of pups born, num e of various origins intermingle at sea and to males, survival, pregnancy rates, an m a lesser degree on land. They remain at sea are measured annually. Management i at holding the population at its most pro size. Research by the United State 1 A revision of Circular 169 under the same title by Baker, Wilke, and Baltzo, 1963. ordinated with that of Canada, Japan, and • Ralph C. Baker, formerly Assistant Director f or U.S.S.R. by the North Pacific Fur Seal r Resource Development, Bureau of Commer cial Fish­ eries, Washington, D.C. 20240; Ford Wilke, Labora­ mission. tory Director, Marine Biological Labora tor y, Fifty to sixty-five thousand young male Bureau of Commercial Fisheries, Sand Point Naval Air Station, Seattle, Wash. 98115; and C. Howard Baltzo, are harvested annually from June to August. formerly Program Director, Pribilof Fur Seal Program, Females are taken if necessary to maintam a Bureau of Commercial Fisheries, 6116 Arcade Bldg., Seattle, Wash. 98101. specified population size. Products from fur seals include , an­ first experimental cargo of 13,000 pelts froJ imal food, and protein extracts. Canada and the Southern Hemisphere appears to have bee Japan each receive 15 percent of the skins and taken at the Falklands in 1784 by the crew ( 70 percent of the net proceeds from skins sold the American vessel States from Boston. by the United States is paid to the State of In the 50 years that followed, the fur se. Alaska. rookeries on Islo Alejandro Selkirk (former Mas Afuera) , Juan Fernandez, the SoutJ Shetlands, Prince Edward, the Antipodes, an EARLY HISTORY OF many other islands were destroyed as fast FUR SEALING they were discovered. Literally millions (] In 1742 Georg Wilhelm Steller drew up pelts were taken to the Canton market to tra the first scientific description of the fur seal for tea, silks, and other products of Chin' after he had survived the wreck of the vessel The populations of fur seals south of tH commanded by Vitus Bering off what is now equator were rapidly decimated. Some hero called Bering Island in the Commander Islands, survived, however, and still live off the coas U.S.S.R. These islands are one of the three of South Africa, South America, Australi. principal breeding grounds of the northern New Zealand, the Galapagos Islands, and som fur seal. of the subantarctic islands. In 1783 Gerassim Pribilof, navigator in The exploitation of the Alaska herd at fir' the service of Imperial Russia, joined the search followed the same destructive methods as thos for other breeding grounds of the North Pa­ pursued by sealers in the southern seas. Twi~ cific f ur seals. The Russians originally came during the Russian administration the herd 0 to this area in search of sea , and here the Pribilof Islands was threatened by ann they found fur seals as well. Each spring the hilation: first, through failure to restrict th seals were seen to swim northward through numbers of seals killed, and later by failu , the passes of the and dis­ to give the females adequate protection. Russi appear into the fog and mist of the Bering forbade the killing of females after 1834, bl Sea. In 1786, 3 years after his search began, according to H. W. E lliott" the ruling was n< Pribilof came upon the islands that now bear enforced until 1847. Elliott was told about his name and found fur seals along the beaches wall of ice that prevented the females fro] in seemingly uncountable numbers. Almost landing on St. Paul Island and forced them 1 immediately the teeming rookeries became a bring forth their pups in the water or th source of sealskins for the fur markets of the storm-tossed surf, which killed many of tli world, at about the time the 13 colonies on mothers and most of the pups. The tru~ the Atlantic coast of were about this catastrophe and the condition of th forming a new nation. Today northern f ur seal population in 1836 cannot be verified. B seals breed on the Pribilof Islands, St. Paul 1867, when Alaska was purchased, the set and St. George, in the eastern Bering Sea, the herd was reported to be thriving. Commander Islands, Bering and Tyleni, in the After the purchase of Alaska by the Unite western Bering Sea, and on Robben Island off States, Congress passed legislation to prote Sakhalin. Small colonies have become estab­ the fur seals of the Pribilof Islands from recl lished in the Kuril Islands between Kamchatka less slaughter. A number of independel1 and Hokkaido and on off companies had begun sealing on the islan California. and had taken about 300,000 skins the fir' T"wo years before the discovery of the Prib­ season. To prevent this destruction, an A ilof Islands, adventurous skippers from New of Congress of 27 July 1868 prohibited the kH England and had discovered commer­ ing of fur seals, and on 3 March 1869 the island cial pos ibilities in the great herds of fur seals along South American coasts, in Ant­ 3 Henry W. Elliott. 1887. The fur-seal industl arctica. and off South Africa. Even though of the Pribylov group, Alaska. In George Bro the Spaniar ds expelled British sealers from the Goode, The fi sher ies and fi shery industries of the Unit States, sec. 5, vol. 2, part 18, pp. 321-393. U.S. Go Falkland Islands in 1770, the United States' ernment Printing Office, Washington.

2 were et a ide by the .S. Goyernment a a In 1870 the Alaska Commercial Company, peeial re en'ation for the protection of the composed of several sealing competitors who . nly local nati"e were allowed to had compromised in 1868 to gain control of the kill fur ~eal . and then only for f od. A year resource, wa awarded the United States' first later the L .. Trea ury Department \\'a~ au­ 20-year contract to seal on the Pribilof Islands. thorized to I a~e exclu i"e righL to take 8eal Under the first 20-year lease, the Alaska Com­ on the i'land-. ,,'ith the tipulation that no mercial Company took 1,977,377 seal~kins. female- were to be taken. Further legi lation Under a econd 20-year lease (to the N 01'+ l in Lei'! authorized the ecretary of the Trea - American Commercial Company), onl) 342 ;1 ury to e tabli:h catch quota~ and 0]\ n ea.ons sealskins were taken in the period endmg for the Ie ee. 1909. The leasing system was disconb ... ec Fur eal. are ,'ulnerable to captur while in 1910. and since then the Alaska fur a' at ~ea a. well a~ on land. P lagic ealing. or herd has been under the managemt:>n1 (I P taking of fur eaL at . a. began to de\"elop Federal Go,'ernment, first by the Secl t:>t on a comm reinl ,cale about 1 79. A prac­ Commerce through the former Bureau ')f F 1 ticed ext n i\"ely by Am rican. anadian. and erie and now by the Secretary of the lot 1 Japane,e ealer. in the. Torth Pacific. pelagic through the Bureau of Commercial f'i&hrr ealing re ulted in the indi 'criminat killing of the .S. Fish and Wildlife Service. of the. enl . without regard to ag . .: x. 01' the Early pelagic sealing had a de\ number taken. The pelagic tak of ·eal. kin effect upon the fur seal herd. AIm/) reached a p ak of 1. 3 in It 91. lion kin. were taken on the high E'

"Fur ,e I porting around the haidar - ati, e of t Paul li~htcring off the humHed sealskin from th \ IIla~e 0\('. -\. ~l..clch h) IIc.'nr) \Y. Elliott, who ,isited the Pribilofs for the Trp ment and tht mith onian Insliluti n in 1 i2, shortl) after the purchase of the IsI,mds from Russi or bidarrah, \ IlS made of ~ca I ion skin . am as-co, cred bidarrahs arc still used in hip to

3 1879 to 1909, and many of the seals shot or maximum sustainable yields of fur seals in speared in the open sea vvere not recovered. the North Pacific. It provides for a Fur Seal The effect on the Alaska herd vvas disastrous, Commission comprised of representatives of because females made up 60 to 80 percent of the four Governments to coordinate research the pelagic catch. In 1912, vvhen the first and manag ment for the northern fur seal. complete census vvas taken by David Starr It al:o provides that an ada and Japan each Jordan and George A. Clark, 215,900 seals shall receive 15 percent of the seal kins taken vvere counted or estimated on the Pribilof commercially by the United tates and the Islands. Although scientists believe this es­ U.S.S.R. timate vvas too lovv, the Pribilof herd had un­ The Fur eal Act of 1966 (Public Law 89- doubtedly been reduced severely, and the 702) puts int effect domestically the inter­ smaller herds off the Pacific Asian coast vvere national Convention. It provides for the con­ faced vvith . servation and protection of the fur eal and After extended diplomatic negotiations and and for the admini trati n of the a long series of ineffectual bilateral agreements, Pribilof I lands. the United States, Great Britain (for Canada) , L'nder int rnational protection and rational management, the Ala ka fur eal herd ha Japan, and Russia concluded a Convention on increa eel from the low point f about 216,00 7 July 1911, for the protection of the fur seals in 1912 to it pre nt level of over of the North Pacific. Pelagic sealing was pro­ 1 Vt million animal . Fr m 1 ·10 to 1967 the hibited except by aborigines vvith primitive herd ha provided an ave rag . 9,7. male vveapons. Each country vvith fur seal rookerie seaL kin . Since 195 , over 73 ,00 eals have agreed to share 30 percent of its annual take been harve. ted or taken for re earch under of sealskins-Canada and Japan each to re­ management policie approved by the ~ Torth ceive 15 percent of the sealskins from the Pacific FUl eal Commi ion. Pribilof Islands and the 15 percent of those from the Commander Islands; and Canada, DISTRIBUTION AND MOVEMENTS Russia, and the United States each to receive OF SEALS 10 percent of the pelts from Robben Island. Worldvvide political events affected the The northern fur seal, an abundant and international agreements protecting the fur widely ranging mammal, i eldom ob eryed seals. The Convention of 1911 provided for alive except by fishermen and eamen \yorking the first time a sound basis for the manage­ offshore or by visitor to the Alaskan and Asian ment of the North Pacific fur seals. It re­ islands where the seals breed. Eyery winter mained in force for 30 years, until terminated beachcombers find fur seal carca e, mostly by Japan on 23 October 1941. From 1942 to young ~eals that were pup the previous sum­ 1957 the Pribilof herd vvas protected by a provisional agreement betvveen Canada and the mer, on beaches from the United States, vvhich reserved to Canada 20 south to northern California. Dead fur seals percent of the skins taken each summer on have not been reported from beaches south of the Pribilof Islands. As a result of World northern California, probably because few War II, control of Robben Island and the Kuril young fur seals migrate south of here. Islands passed from Japan to the Soviet Union, Originally the fur seals that breed on the giving the U.S.S.R. complete control of all fur Pribilof Islands, on the Commander Islands, seal rookeries off the Asian coast. and on Robben Island and some of the Kuril On 9 February 1957, a nevv interim North Islands were described as three separate spe­ Pacific Fur Seal Convention vvas concluded by cies because of supposed differences in color Canada, Japan, the Union of Soviet Socialist and in shape of head and neck. They have Republics, and the United States, similar in since been found to be indistinguishable by form to the 1911 Convention. The nevv con­ physical appearance and measurements; their vention, as amended by a protocol in 1963, has vvintering grounds overlap; and tagged seals, as its principal objective the achievement of especially young males, are regularly found in

4 I

In late June this 9-year-old bull fur seal is approaching the age when he will compete actively for t r on a rookery. Probably the territory he seeks will be near the spot where he was born. small numbers on rookery islands other than seas southwest of Kinkazan Penm where born. The recently reestablished col­ northern Honshu and into the Sea of • 'onies in the Kuril Islands and on San Miguel Northern fur seals now breed un tl Island, Calif., contain animals from Asian and lowing islands: St. Paul and St. Geo gt> I Alaskan rookeries. Therefore, the fur seals and Rock of the Pribllof g of the North Pacific are now considered to Alaska; Copper and Bering Islands belong to a single species, Callorhinus ursinus. Commander group off Kamchatka; Rob Migratory routes extend over vast areas of Island, off Sakhalin; Nizkaya, Visokaya K the Pacific. Except as stragglers, few fur seals traya, and Tchiornaya Rocks in the Ku I range north of the Pribilof Islands. They Islands; and San Miguel Island, Calif. Th migrate south to the Channel Islands off Santa Soviet Institute of Oceanology reported that Barbara, Calif. In the west they range from seals, but no pups, were seen on the Kuril the vicinity of the Commander Islands to the Islands of Paramushir and Urup. Fur seals

5 Summer on a typical seal rookery-Kitovi Roo ery on St. Paul Islan Characteristically, the seals return each summ to the rookeries whe they were born. In M and June come the hare) bulls or be a chmaster: later the females.

13 JUNE. - By mid-June most of the harem bulls have established stations and await the arrival of the females., 28 JUNE. -By late June, the first females arrive, and harems begin to form.

6 rhe pups are born soon Ilter the females come hore. The pups grow tronger, they wander rver the rookery and rventually gather in fI'0ups or pods, while heir mothers spend much be at sea searching for DOd.

3 A GUST. - In late July or early August the harems begin to e / 8 JULY. - In early July the harem groups remain closely knit.

7 of the Kuril Islands were nearly exterminated Vancouver Grounds reaching from south of thl by sealers in the 1890's; in 1955 and 1956, Columbia River to the north end of Vanco uvel however, Soviet investigations revealed their Island, the Fairweather Grounds reaching f ron presence once again, though in small numbers. Sitka to Middleton Island, and the Pribilo About 80 percent of the northern fur seals Grounds in the eastern Bering Sea. Seals alsi live and breed on the Pribilof Islands. congregate on Portlock Bank off Kodiak Islan( International research reveals intermixing and near the . between fur seals of the eastern and the west­ Most people living along coastal areas 0 ern Pacific. From research on the intermixing the western United States, particularly Car of seals from American and Asian islands, sci­ fornia, are unaware that many thousands entists believe that 20 to 30 percent of the seals fur seals feed and rest for several wint found off the coast of Japan in winter and months on the nearby . spring come from the Pribilof Islands. Seal­ The top speed of fur seals in water is n tagging studies by the United States and the accurately known. For short distances the Soviet Union indicate that male seals from the can keep ahead of a ship moving at 8.7 to 13. Commander Islands make up about 1 percent knots (16.1-24.1 km. per hour). They can of the annual commercial kill of seals on the overtaken if chased persistently by a ship wit Pribilof Islands and that the Pribilof Islands a speed of only 7.8 knots (14.5 km. per hour) contribute 10 to 25 percent of the seals har­ On the ocean surface the seals are ofte vested each year on the Commander Islands. seen asleep, floating on their side or back, wit Unless sick or injured, fur seals rarely land all four flippers folded or with one or mor from the time they leave their rookery islands idly stretched into the air; however, on th in the fall until they return the following island rookeries, activity continues unabat spring, summer, or fall. Exceptions are on day and night. Samalga Island near the west end of In the open ocean seals may occur singl Island and Ano Nuevo Island and at least one or in small groups. Food will often attra of the Channel Islands of California. Seals, concentrations of 6 to 20 seals. believed to be young males, were seen hauled groups may be in view at one time. out on a reef at Samalga Island; a male came grouping of up to 100 has been observed. Th ashore on Ano Nuevo Island in 1962, and two density of seals on wintering grounds is e landed in 1967. A pup born on the coast of tremely variable, ranging from none to ov Washington in July 1959 "Was one of very few 70 per square mile (27 per square km.). known to be born away from the rookery is­ Seals range through waters with surfac lands until the existence of a small colony of temperatures of 30° to 59° F. (-1 ° to 15° C.) breeding seals on San Miguel Island was ver­ They are most abundant in waters with surfa ified by University of California investigators temperatures of 47° to 54° F. (8° to 12° C.) in July 1968. This discovery raises the question What seems to be a preference for water of whether the fur seals that were exter­ certain temperature may actually be a r minated from islands off California were Cal­ sponse to availability of food. l01'hinus, the northern fur seals, or Arcto­ Bull seals winter principally in Alaska oephalus which is now restricted to the southern waters. They have been seen most frequentl hemisphere except for a small population at in the . Guadalupe Island. The fur seals arrive at the P r ibilof Islan Seals are usually seen 10 to 90 statute in a progression of ages, with the older male miles (16-145 km.) offshore and are frequently and females arriving before the younger one ~ most abundant between 30 and 70 miles (48 Bull seals begin landing at their breedin and 113 km.). Pelagic sealers gave names to rookeries on the Pribilof Islands in late April the ocean areas where fur seals concentrated. and increasing numbers appear until the mid The important locations off North America are dIe of June. The oldest bulls arrive first, an the Farallon Grounds extending from Point others follow in order of age. The oldest an Conception to Point Arena off California, the earliest females appear in June. Occasion

8 yearlings have appeared ashore as early as PHYSICAL CHARACTERISTICS late July, but most of them land in October The fur seal's physical features are adapted and early November and remain only 2 or 3 to meet its needs. The fur seal has unu.ually weeks before going to sea again. The small large fli ppers compared with other eals and proportion of yearlings that come ashore in­ sea . The large bare flipper area is useful cludes more males than females. for cooling, especially on land, since den e f r I The location and composition of the rook­ effectively insulates other parts of e hod bries change as fall approaches. During au­ The fur, which has over 300,000 hair p [tumn, most of the animals ashore appear to square inch, is so impermeable to watel t iPrefer areas farther up on the beaches than the skin remains dry even when the sea during the summer. Seals make their main or scratches itself in the water. l\Iolt i exodus from the breeding grounds during N 0- complete because some of the hairs remair iVember even while some yearlings may be still in the skin more than 1 year. Body te arriving. ature is about 100 0 F. (38 0 C.). 0, elh The bulk of the commercial kill, made up from unusual exertion or sunshine wh of 3- and 4-year-old males, arrives in late June, land causes obvious discomfort. Body ~E'I July, and early August, while the other young atures above 107 0 F. (42 0 C.) cause he

  • 10 Adult male seals spend only a few years cent of th f mal of their lives as masters of a harem. Adult Thereaft r , the J r males remain on their territories an average of 50 days. They are seldom able to acquire a harem until they are 10 years old. About one-third of the males with harems are re­ placed each year. The active harem life of most males, then, is for 3 or 4 years when they are 10 to 14 years old. pup are born dUl'iw" t h fi r t Biologists of the Bureau of Commercial F emales gh' IJirth to on J UI Fisheries have made age determinations for after fir t coming a hoI' on tl seals up to 26 years old. Tagged seals 21 years day later they <1l' impr gn,l old were recovered in 1962. The maximum single mating, and ~ om tim In life span is believed to be about 30 years. Most week make a trip to . ea t f fur seals have their first pup when 4 to 6 years cur ion may la, t ;j t( 1 da', old. In the prime of their reproductive life, days. Females nul' e onl, th r when they are 8 to 13 years old, nearly 90 per- which they recogniz I y

    Fur seal pups sleeping on the sand near Tolstoi Rookery, St. Paul Island, in late Jul), The are less than a month old, are resting during one of the 5- to 14-day inten als bchH~ en Dursm cation. ~ound, and mell. The pup mu t ob­ time in the water. At first they swim rathe tain enough of the rich milk. containing about awkwardly with head high out of the wate 50 llercent fat. to ul'vi\'e between the widely but they soon gain skill and endurance. paced feeding . During the nursing period During the first day or two after birth 0 the pup', ,tomach occupies most of the body her pup, the female attempts to protect it an cayity. Little food other than milk is taken sometimes carries it in her mouth. Then hy the pup hefore it 18aYe- the island in the fall after, the female flees from an intruder wit~ at weaned age of 3 or 4 months. By the time out making any attempt to protect her pu~ the young are ready to leaye the rookery in No­ A pup that falls into a crevice in rocks di vember, the larger ones weigh over 30 pounds because the mother is unable to retrieve it.

    (14 kg.). • T ur ing ends abruptly when the fe­ male lea\'es the i land to migrate soutl1"ward. MORTALITY AND DISEASE The pup mu t then begin to find their own When the Pribilof herd was small, less tha food in the form of fi h and squids. After sev­ 5 percent of the pups died on land, but wh eral month at ea they may not have gained, the herd was at its p~ak in t~e 1950's the pr or may e\'en have 10_ t weight, but their con­ portion that died a5C¥c~nd varied fro tour are more nearly tho e of an adult. year to year. In the worst years 20 percen A much-repeated mi statement is that or more of the pups died. Now, with the her, young fur eals are taught to s·wim. The pups reduced, mortality of pups has decreased. can swim from the moment of their birth, and has ranged from 5 to 12 percent since 196 ~ none vel' recei,'es les ons from its mother. Hookworm infection and malnutrition well In early August most pups begin to spend some leading causes of death in fur seal pups whe'

    c.lr .1 fe\\ bro\\ n, } clio", almo t \\ hit , or pi bald seal pups are born. Light colored are o(:(:.I\iono ll) ~ee n , but true albino rarely urvive.

    1:2 the population was high. Other known causes bility to obtain adequate food are the greate t were inj uries, congenital defects, and bacterial hazards during the first year at sea. At this infections. Hookworm infection has now ap­ time the pups make a sudden transItion from parently declined with the decrease in popu­ nursing to fin ding their own food in the cold , lation size. Although it ranked second as a stormy, winter ocean. Many perish. As high ~ause of death in 1967 and consistently is among as 85 percent of some year classes may be l()~ t the three leading causes, hookworm infection by the time they are 3 years old. Recentl may now kill an appreciably smaller fraction the many scraps of synthetic netting i 111'0 )f the pups than it did in the 1950's. Malnu­ overboard by fishermen have become a hazel trition, infections, and injuries continue to be to seals. A seal will put its head tIll 0 important causes of death. loop like objects it finds floating in the

    The relative importance of the causes of Lar ge pieces of netting impede a seal L 0 mortality for the entire population is extremely it is unable to feed. Small pieces are a Ei ifficuIt to determine because of problems in drance but do the most damage by Cl t ;ampling and identification of the cause of through the skin and underlying fat and IT :leath. causing infection, crippling, and death. Biologists assume that many of the pups the meshes have worked into a snug po . 1 ~ hat starve do so because their nursing mother deep in the dense fur the seal can neve .s killed at sea. Rejection of pups is common itself of the net. When one animal ha d lmong harbor seals, however, and may also and disintegrated away from a net, ~ontribute to losses from starvation in fur seals. can be enmeshed. Hookworm infection in the fur seal has been ~xtensively studied. Hookworms occur in the POPULATION 'issues of seals of all ages. The parasites are Several methods have been use· t;lparently able to penetrate the skin, at least the size of the fur seal popuJat m bare surfaces such as the flippers. Pups the Convention of 1911 first gave i tre infected through nursing, and the parasite protection to fur seals, the ri il)' l.ttaches principally to the small intestine. gloodsucking by the worm causes severe ane- about 200,000 animals, 'which co llc I ia. By fall, the intestinal infection dis­ with reasonable success. Aft ppears, but hookworms are retained in the bulls were counted becalFe r )lubber, mammary tissue, and perhaps other constant interchange of ani! 1<: -issues. There is no evidence that adult worms eries made a meaningful (;0 ~ 'rom the intestines move into the blubber. Until 1948, the Bureau of Fd'"t. ~ arval worms that penetrate the skin hatch the size of the herd ann ua l1y 'rom eggs passing from the intestines of pups. calculated geometric rates ~ easons for variation in mortality on land from lished just after the turn of t ear to year are not clear, but one cause may calculated and actual increas" )e variation in the effect of weather on the until the mid-1930's, but by HJ lUmber and infectivity of hookworm larvae. was discontinued because 1'0 h •. . igh mortality of pups on land is cor related calculating the increase rate '>'l~ ith low survival to age 3 even though mor­ racy, for a population that, a.s i ality on land may be only 20 percent of the of the growth potential. ThE; e:::.t .r otal loss. This fact suggests that in years number of pups born in 1967 ,vas 38 f high mortality among pups on land, many total Pribilof herd was about 1,400 Ol 'urviving pups are weakened and are unable August 1967. o withstand the rigors of ocean life. The seals on all other North Paclnc 1 Little is known about the causes of death (Commanders, Robben, KUl'lIs) total 300,0 Lt sea. The and great white in late summer. The her d on the Comma .de ~at seals. Parasites probably also kill seals. Islands has a rate of increase similar to +-he ~ maciated young seals that drift ashore in r ate demonstrated by the herd on the Prib 10 inter suggest that violent weather and ina- Islands when it was growing rapidly. The

    13 population on Robben Island is giving some seals is limited for the most part to the 3- an( indication of approaching its upper limit­ 4-year-old males. In 1918, the U.S. Govern death rate among pups is increasing. Seals ment determined age-length relation fron on the Western Pacific islands have a higher measurements of seals of known age, bran de reproduction rate among young females than as pups in 1912. Until recently this age-Iengt those on the Pribilof Islands. The change in relation has served as the basis for selectin growth rate as these herds "mature" will be animals that are to be harvested commercial! followed with interest by students of animal The kills are now classified into age categori population dynamics. by counting the annular ridges on canine teet Satisfactory management requires some from a 20- to 30-percent sample. Also th measure of changes in various segments of the overlap of lengths between ages is better undel population. These measurements include num­ stood through extensive recent measuremen ber of pups born, survival of year classes, num­ of tagged seals. ber of bulls, pregnancy rates, and mortality The n umber of seals killed each year h at various ages. Biologists supervised the varied for a number of reasons. From 191 tagging and marking of over 600,000 seal pups to 1917, seals were killed only by the residen between 1947 and 1966. Currently, each year of the Pribilof Islands to use as food. Co about 12,500 pups and 3,000 1- to 3-year-old mercial killing for skins was resumed in 191 seals are tagged and 10,000 pups are marked after the 7-year cessation. From 1918 to 192 temporarily by shearing a patch of fur from harvests of seals were high in relation to po the top of the head. By combining (1) in­ ulation size because of the accumulation formation from tag recoveries, (2) age classi­ males. The kill declined after the excess mal fication of the kill through counts of growth were removed, but thereafter steadily increase rings on teeth, (3) pregnancy rates, and (4) until 1940. From 1940 to 1955 it average pup mortality counts, Bureau of Commercial about 66,000 males annually. Since then, t Fisheries biologists estimate the number of kill of males has varied from a high of 96,00 pups born. An improved method of estimation in 1956 to a low of 30,000 in 1959. Part uses the mark ratio resulting from random, the difference between the e extremes resulte temporary marking of pups; the number of from an extended season in 1956 which rna pups marked; and the number of dead pups. available a larger proportion of the 3-year-ol The results are checked for accuracy by making group, but recent ft.uctuations are caused pI' complete counts on small rookeries. marily by variations in year class survival. In managing the fur seal herd, the Fe MANAGEMENT eral Government has adhered to a policy taking pelts from seals considered surplus F ur seal habits are such that a program of wise utilization is readily devised; however, breeding requirements. From 1923 to 1932 the success of the program depends on inter­ a minimum yearly breeding reserve of sever national cooperation because the seals live thousand bachelors was provided by markin much of the time outside territorial waters. them with a brand or by shearing a patch In Alaska, with few exceptions, fur seals come fur, then permitting them to return to the se ashore only on the Pribilof Islands, always This precaution may not have been necessar about the same date each year. Because seals but it ensured that the number of males esca are highly polygymous and the sexes are born ing the kill would be adequate. in equal numbers, it is possible to take many From 1932 to 1955, a sufficient breedin males without adversely affecting the produc­ stock was assured by limiting the killing seaso tivity of the herd. The young males, whose each year to a period from about the middl pelts are most valuable, habitually haul out on of June to the end of JUly. Only the male sea the islands apart from the breeding animals 41 to 45 inches (104-114 cm.) long were take] in the harems, so they are easily obtained. as they appeared in the daily drives on th Seal measurements guide biologists in se­ islands during the sealing season. From on lecting seals to harvest. Harvesting of the half to two-thirds of the animals in this grou

    14 The scene on Tolstoi Rookery, St. Paul Island, in late July illustrates the fact that mid-July a a nursing females are feeding in the sea and therefore many more pups than fe males are on lh

    are 3 years old, and most of the remainder are to be taken early in the foll{, ;v I ~ years old; a small number of 2- and 5-year­ casts of year class strength m old males are included. The proportion of 3- 3-year-old seals appear ~n th and 4-year-old animals taken depends on the the process of development. T relative survival of year classes. based largely on averages. Tnt l In recent years Bureau of Commercial Fish­ accurate information m an 'tv eries managers have adjusted the sealing sea­ have not been satisfactory ( son to the number of young males that are or \veak year class. available and to some extent to the age and Biologists consider the nlln size of seals that they wish to harvest. Early that have been escaping the kill m seasons produce a larger proportion of 4-year­ quate, and, as a result, the UJl I' old seals and later seasons a larger proportion of harvestable male seals ha bee of 3-year-old seals, because the older ones ar­ recently. This change permit clo er c rive earlier. The season for male seals now by taking animals that would hu\ e begins in late June and ends on 31 July. j ected solely because of size under f- e Close cropping of 3-year-old seals during a late limit even though they had kin f season leaves relatively few 4-year-old males quality. The number of harem hulls Clncl th kill of males failed to inCl'e<1.R after 1010, and til i ('OUI' (' of fur pnll'f> illg'. failure caused biologists Lo conclude by 19G2 pal'; I r1 i nt() h r E that the herd had reach d, or \\ a 11ral', its of th ·i,' 'hi k('r peak of deve]opm nt. One m;Jjor f"do}', in theory, that prrrllldes fll1'Lhrl' ]los ' illl!' growl h of the herd is th!' limited food supply availalll ' to the nursing femal(ls in tlH' . mnn1l'r ilnrl to the pup. during their first mOll hI' al ('il in the fall. \Yith the herd at its peak, th prochl'( iOI1 of PUllS wn. high, but su]'vi\·,t1 to ag<' :~ wa. much more variahle lh.m wh n tll h'I'cI wa smaller and grow ing l'

    16 Many seals are now held ancl stl1died ill captivity. Stnclie are expanding on sp r.ialized aspects of seal hiology. Srieni isis n

    SEALING ON THE PRIBILOF ISLAND

    The harE'm 01' rookery area and adjacent hauling grounds of the bachelors and idle bulls are at widely separated points along the south­ ern and eastern beaches of St. Paul I land and along the nOl thern a d we tern shores of St. George Island. Owing, in part at least, to the mg the :ullIm 1 tl high bluff of St. George Island, finly about plel lent d II} \I(,tlt \ 1

    When hauled out on land. fur seals are (,:1,il) their u ula ing fur. they mu t hE.' driHn . 10\\ I) Islands and native student from elsewhere in verted to meal and oil in a byproducts plant Alaska. operated by the Government. About 350 tons The roundup of seal on the Pribilof Islands of meal and 40,000 gallons of oil were pro­ is a imp Ie operation. On a typical day in the duced each season and sold to the highest bid­ St. Paul I land sealing season, a crew of 35 der at Seattle, Wash. The meal was used as sealers proceeds in trucks from the vil­ a protein supplement in animal feeds, and oil lage to the hauling ground. Leaving their ,vas used in soap making and tanning. The trucks, the sealers cautiously 'work their way byproducts plant became uneconomical after upwind along the beach between the bachelor 1961 and was discontinued. Experimentation seals and the water. When the line of escape revealed, however, that seal meat, bones, and to the sea has been cut off, it is an easy matter organs are an excellent source of protein for to surround several hundred seals and drive ranch . All carcasses on St. Paul Island them slowly inland a short di tance to the grass­ are now ground, sacked, and frozen. The lim­ covered killing field. One 01' nvo Aleut boys ited St. George production, which was never provide the only guard necessary to prevent a large enough to justify a reduction operation, stampede of the animals back to the beach and is being used as a source of a special protein. the open sea. The sealing crew is well trained, and clubbers are adept at selecting animals of PROCESSING AND SALE OF commercial value. The work is efficiently or­ FUR SEAL SKINS ganized and carefully supervised. One small All U.S.-owned skins are processed and sold group of seals after another is separated from by private companies serving as agents for the the main group. Seals judged to be less than Government. About 100 different operation~ 41 inches (104 cm.), or to have poor quality by highly skilled workmen are involved in con­ furs are permitted to return to the beach. With verting Pribilof Islands sealskins into the minimum restraint, selected animals are quickly beautiful, soft, supple furs sold to the and humanely dispatched with a blow on their at public auctions. Contractors for sealskin fragile skulls from a hardwood pole. The time processing are selected through competitive required to kill a group of 6 to 10 seals and procedures. release rejected ones averages 2 to 3 seconds Sealskins are greatly changed in appearance pel' animal killed. Any system that required during processing. The first major step in the more movement and handling of the seals processing of sealskins is the removal of the would cause greater stress for the seals ano coarse guard hair that overlies the dense he more dangerous for the workmen. j soft underfur. The pelts are thoroughl)\ In a matter of seconds, the Aleut sealers washed and subjected to moist heat to loosen strip each sealskin from the carcass. From the guard hair so that it can be extracted b)\ dead seal to cured but unprocessed sealskin is scraping. After the unhairing process, the a routine operation. The day's collection of pelts are tanned and dyed. U.S. Government skin i~ transported by trucks to the village sealskins have been dyed principally in fom curing plant. Here they are thoroughly soaked colors: (1) black, (2) rich dark brown, (3) in cold sea water, "blubbered," and brine­ neutral brown with overtones of bluish gray cured. A mixture of salt and boric-acid and (4) midnight gray with highlights of sii po" del' i applied to the skin side of each cured vel' and a subtle blue cast. Recently, bleachin~ and drained pelt to dehydrate it and prevent has been successfully done and fur of a light bacterial action and fungous growth as the color is being produced. Closely sheared pel p It are packed in barrels for shipment to that are not unhaired have been introduce the mainland. where they are held in cold stor­ to the market as a new type of fur suited to age until I)l'OCes. ed. more informal garments. Six to eight skin eal cal'ca~ es are uitable for making meat are required to make a coat. meal. oil. 01' animal food. On t. Paul Island Pelts of northern fur seals have consistent} from 191 to 1961. mo t of the carca ses and brought the highest price of all sealskins 0 th blnbh r removed from the kin v,ere con- the world market. The world human popu

    1 Skins that have been washed, cleaned of blubber, cured in a saturated salt solution, and dial> d with salt and boric-acid powder, rolled, and tightly packed in barrels for shipment. lation is increasing rapidly, but only moderate The future of the Ala!':\k increases in the supply of sealskin can be ex­ seems assured as long as the pected-a situation that should strengthen the world continue to work togethr . market for fur seal garments. of problems peculiar to such . i _ Over 2 million sealskins from surplus males life populations. An epilogue c have been taken by the Government since res­ fur seal story is found in the W ol'd toration of the herd was begun 50 years ago. Bertram, an English biologist, "" ft Net profit to the Federal Treasury from the visit to the Pribilof Islands: "01' U.S. share of these skins has exceeded $25 no higher praise than sincel'ely to. . million. Part of the money from the sale of planning and agreement for the f • U1 skins is made available by Congress to the be as beneficient and rational as f Bureau of Commercial Fisheries to defray ex­ the administration and conservatIon . f penses of administering the Pribilof Islands herd during the last forty years.'" and the fur seal industry; 70 percent of the net proceeds are given to Alaska under terms • G, C. L. Bertram. 1950. Pribilof fur seals. Arcti • of its statehood Act. J. Arctic lnst. America 3(2): 75-85. MS. #1812 GPO 996·750

    19

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