ARLIS. S9503 Alaska Resources Library & Information Services ·~ , Anchorage, Alaska ·
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STATUS OF MARINE MAMMALS IN THE EASTERN NORTH PACIFIC OCEAN By Karl W. Kenyon For Department of the Inte:dor 102 Statement Task Force B of the I'c.o 00 ('/)I Task Force on Alaskan Oil Development ('I) 0gr. LO L.· LO • 29Julyl971 I'('I) ' ('I) I . i Bureau of Sport Fisheries and Wildlife Marine Mammal Substation Naval Support Activity, Bldg. 192 Seattle, Washington 98115 Library ARLIS. S9503 Alaska Resources Library & Information Services ·~ , Anchorage, Alaska ·. t CONTENTS Introduction . * • • • • • • • • • • • • 1 Sea Otter . '~ . 1 Northern Fur Seal . .; . 6 Guadalupe Fur Seal 8 ,.. Steller Sea Lion ~ •••••• ·h· 10 California..· Sea Lion • • • • • • • • • • d • • • • • • • • • • • • 13 - Harbor Seal . ~ . 14 Northern Elephant Seal •••••.• 16 The large Whales {class Cetacea) 17 ( Whaling in the North Pacific Ocean (Rice 1971a) 17 Status of Species (from Rice, 1971 b) Blue whale 10 Fin whale • 15 Sei whale •• 17 Bryde 1 s whale • • • • • 20 Minke whale . • • • . • • • • • • • • 21 Humpback whale. • • • • . • • • • . 2'2 Gray whale . • . • . • • • • • . 24 Black Right whale • • 25 Bowhead whale. • • • • . • 26 Sperm whale .••• · ••• 28 Giant bottlenose whale 30 Gray Whale .•...• . 18 The Toothed Whales . .. 21 Porpoises and Dolphins 21 References Cited . 24 ·r ..... '-- STATUS OF MARINE MAMMALS IN THE EASTERN NORTH PACIFIC OCEAN B-y: Kad W. Kenyon Introduction The purpose of this report is to summarize the best information available, as a resource ~escription~ of marine · mammals in certain areas of the eastern North Pa~ific Ocean. These areas include Prince William Sound and waters contiguous - to shipping lanes along the coast of Southeastern Alaska and .. ) British Columbia, the inland pas sages of the Strait of Juan de Fuca and Puget Sound and southward to Mexico. The status of tnar~ne mammals of the Beaufort, Chukchi, and Bering Seas is discussed separately by Ja.mes W. Brooks. Sea Otter (Enhydra. lutris, order Carnivora) --- During the 19th centm:y the sea otter was brought to the verge of extinction throughout its range by unregulated exploitation. ·l ·.. By 1911 when survivors were afforded proteGtion under an inter- '' :! national treaty (U.S. Congress, House, 1912) a remnant colony remained in Prince William Sound. Populations south of Kayak Island, along the coasts of Southeastern Alaska, British Columbia, Washington, and Oregon were by ~hen, or soon became, extirpated. ~. ~. ( ~ ;_' '!/ ~,·~--;rr~·---;-:·-·" -· ··-' ··~~;...-'''--~-.,.--... ,-·~· - • ___,__. ~ c· .. 2 Protected for 60 years from exploitation, recent surveys indicate that the Prince William Sound otter population now (1971) numbers about 4, 000 aninutls (J. Vania and K. Schneider, pers. comm. ). These animals are found along open coasts and protected waters of Prince-William Sound and adjacent mainland· where water depths (to about 180 feet) permit feeding. Because the sea otter failed to move southward' naturally, - the State of Alaska, in 1965, undertook a program of restocking . vacant parts of the sea otter's former range. A total of 412 otters . were translocated to Southeastern Alaska (table· 1) and, by July 1971 an additional 194 otters were liberated on the coasts -of B·ritish Columbia, Washington, and Oregon (J. Vania and K. Schneider, pers. comm. 1971) . .....--Surveys in the areas of translocation reveal that many (exact number unknown) otters survived in the new locations anC. that young have been born in at least some locations. A small colony that survived after 1911 on the cent:ral California coast now numbers over 1, 000 animals. Most of this '( '.• population is spread along about 110 miles of coast from Monterey . ·~ i ; '< Bay to Morro Bay (Peterson and Odemar, 1969). ••; ... 3 ..... Water pl)llution of any kind which, like oil, penetrates the sea otters' soft insulating fur and causes the skin to become wet, quickly causes death through exposure. The fur of the sea otter is similar in function to the feathers of marine birds in that it is dry at the base and protects the sk~ with an insulating blanket of air from contact with water. The sea ot)er. lacks blubber as an insulating agent. (Kenyon, 1969). - . -~ I .,· -c .·.' \ _-.:;:L _____ _ . " . ,• -.:-;-:r-·---:-- ---.-,-·· .... ·· · -·:-':':"~r ~;-::--~--~~~:~~~ -:-;....--·~-T'~"-:"'":"1\-'t::~~..-;.r:--:;o,•,-~~ .. ....,.,.....:o-..-:;o!'l'...,,~~r ... ~~q:-T·"J·~...,-:-:--~..,.. ....... , .... -:-..... f~---:• ... ~--~- .. - "'~ · ·· 4 Table 1. --Restocking Program Year Location of Number of otters introduction translocated Total --· Alaska 1965 Kahz Bay* 23 23 1966 Kahz Bay and Yakutat 30 . 30 1968 Kahz Bay 93 Yakobi Bay 30 Barrier Island 55- Biorka Island 48· Hecata Island 51 Cape Spencer ._( 25 , [30J _- .·.· - 1969 Kahz Bay 58 58 Total ]1_?'=·~ British Columbia 1969 . Near Buns by Island, . Vancouver Island 29 1970 Checleset Bay, Vancouver I. 14 . Total 43 - Washington 1969 Pt. Grenville 29 _..-- 1970 LaPush 30 30 Total 59 .. Oregori 1970 Port Orford 29 29 139 __ _ 1971 S. of Coos Bay ·c-- Port Orford 24 63 Total. j _92- -.. Total outside Alaska . 194 Grand total * Chichagof Island. ·* * These otters were observed, when liberated, to be in poor c.ondition. Acbout half of those liberated off Washington were later found dead, howe~er, survivors were observed subsequently. '~ ! i' .. ,, ·- ···-·······"---.--,·.--;..,:.~~--...,~-:-,~----"·":: ____ ~----· .. ··- ·····~ -~--~·-...,--~,..,._....,.....,_~-·- ·-~-' ..., .... ~! ~so~- 1500 1300 Ma.p 1 ; - Sea Otter transplant locations. l ----------··-· +------+-·--+1---+--soc ' I. ~ 1 p' A c I F I I ~-- I '! ~ 0 c E A -,- ;·1 . ..-. \~,;_-·.. ~-'·: !......--+-----+-----t----+-------1---~--+----+----+----J\., ···':: '~i . ., . '"'-',\1 t I '" . ~:('< "'\ .. -:-::·... ~-~---,_----~---,_----~----+-----~----~---30' r-"'-· .I ' ! ... I ., I 6 Northern Fur Seal (Callorhinu~ ursinus, Order Pinnipedia) A her C. of approximately 1, 4 million fur seals (Baker, Wilke, and Baltzo, 1970) assemble and breed on the Pribilof Islands in summer. In fall, winter, and spring the seals mig=ate to favored· feeding·areas in the North Pacific Ocean to as far south as the Mexican border (Townsend, 1899; Huey, 1942; Kenyon anci . ·, ... , Wilke, 1953; Wilke and Kenyon, 1954) .. A small b~e'eding colony · · ·' was disc'?yered on San· Miguel Island, California in 1968 (Peterson, , LeBoeuf, and DeLong, 1968). This colony in 1971 numbers between .zoo and 300 breeding animals (A. M. Johnson, pers. comm. ). Although most of the seals taken at sea for scientific stuC.ies in recent years ranged from 10 to 300 miles· offshore along the • ·. \ Pacific Coast (North Pacific Fur Seal Commission, 1965; 1969; 1971; H. Kajimura, pers. comm. ), many enter straits seasonally along--- the sout::l.eastern Alaska. coast to feed on herring (Kenyon, 1955). Pelagic sealers of the 19th century took thousands of seals . -·- on the Fairweather g·rounds high in the Gulf of Alaska and only a ... , few miles off Prince William Sound (Townsend, 1899) (Map 2). During the northward migration, particularly in March, Apri~ and May, thousands have been observed in the Gulf of Ala.ska in recent years (Fiscus and Kajimura, 1970).· Apparently, however, or.J.y stray individuals actually enter Prince William Sound. ·(_. .. ......,.,_ ......... _____ _,.,.,,,., ___ ,_,___ ,_, ___ , __________ , ______ ·' 7 From an economic point of view the northern fur seal is the most important pinniped jn the Pacific Ocean. The gross income from sale of skins and by-products in fiscal 1970 was $3,249.325. After processing expenses (Fouke Fur Co.) the net was $2, 713, 436. By-product sales amounted to $3, 000. The numbers of American citizens who. depend for their entire , , . annual income on the fur seal harvest are: Civil Service, Pribilof ..· - natives, 42, and nonnatives, 34; and Fouke Fur employees, about 200. In addition, seasonal worker·s during the fur seal harvest operations include: 136 Aleuts, 35 other Alaskans, anC. 32 non-Alaskans. Thus, the total number of people employed ( full or part-time by the fur seal industry is about 479 individuals. The effect of petroleun1 products in the marine environment on fu,~--seals can only be inferred. Occasionally during the past 20 ·years fur seals having oil L'l their pelage and found dead on Washington beaches have been brought to us at the Marine Mammal Biological Laboratory. We could not determine the exact cause of death. There is, however, no record of a fur seal on the Pribilof Islands, where between 40, 000 and 50, 000 are taken annually, having oil or tar in i~s pelage. This could mean that seals having i : i oil in their fur at sea do not survive to return to the Pribilofs. ,,I ·. 8 The general northward migration route of seals from 'i :. ; southern California to Unimak Pass and the areas of general seasonal concentration are shown on map 1. -· ·- -· -·-···-·-··---· ----------- --·· ···- -------- ----~- --------- --·-·------------·-· ·------- ----- Guadalupe Fur 'Seal {Arctocephalus philippii.- townsendi ~ ·The breeding population of this seal is confined to Guadalupe i . Island, Mexico. In 1965 the population then numbe'red about 6GO , __ ; ,_:,'! i animals {Rice, Kenyon and Lluch, 1965} and now numbers perhaps • .,• I - 1, 000 animals. It is rarely seen north of the Mexican border on the California Cham1el Islands. --------------···-----------.. ( . ------ I . i ':. l_:·t /-· •.' 9 '~60~·. 150° 140° 1300 120° '''':f-.___:__.......-...._.,.~---_,..,.,..-..--p-.-~....,.- :~.. :--. 'l':f",_, ---,....--~----,....---.--- 6 5° '\i Map . · I ;\ -·-···-····-