Chapter III — Species of Special Concern 



The western North Atlantic humpback whale stock 

 assessment indicated that the stock size is an estimated 

 5,543 individuals, the maximum net productivity is 

 assumed to be 4 percent (a default value used for all 

 cetaceans when data are inadequate to estimate the 

 value), and the potential biological removal rate is 9.7 

 whales per year. The assessment indicated that the 

 level of human-caused mortality and serious injury in 

 commercial fisheries and other human activities is 

 unknown, but current data indicate it is significant. 



The central North Pacific humpback whale stock 

 assessment indicates that an estimate of population 

 size for this stock is not currently available, the 

 maximum net productivity is assumed to be 4 percent, 

 and the potential biological removal rate is 2.8 whales 

 per year. It indicates that the level of human-caused 

 mortality and serious injury likely does not exceed the 

 rate of potential biological removal. 



The eastern North Pacific (Califor- 

 nia/Oregon/Washington - Mexico) humpback whale 

 stock assessment indicates that the estimate of this 

 stock is approximately 597 whales, and there are no 

 estimates of maximum net productivity. The assess- 

 ment also indicates that the potential biological remov- 

 al level is 0.5 whales per year, and the estimated 

 annual mortality due to entanglement and ship strikes 

 exceeds the level of potential biological removal. 



The stock assessment for the western North Pacific 

 humpback whale stock indicates that for this stock 

 there is no reliable estimate of abundance, the as- 

 sumed maximum net productivity is 4 percent, and 

 without a population estimate, it is not possible to 

 determine the potential biological removal level. The 

 estimated mortality rate incidental to commercial 

 fisheries is believed to be zero, but without an esti- 

 mated level of potential biological removal, it is not 

 possible to determine what annual level of incidental 

 mortality is considered significant. 



In 1996 the Commission will follow developing 

 issues regarding vessel traffic in Glacier Bay, review 

 the results of Project YONAH, and otherwise provide 

 advice regarding the recovery of North Pacific and 

 North Atlantic humpback whale stocks. 



Bowhead Whale 

 (Balaena mysticetus) 



Bowhead whales occur only in the northern hemi- 

 sphere and are circumpolar in distribution. There are 

 believed to have been at least four separate stocks, all 

 of which were severely depleted by commercial 

 whaling in the late 19th and early 20th centuries. The 

 period of exploitation and extent of depletion differed 

 for each. The western Arctic stock off Alaska (also 

 called the Bering-Chukchi-Beaufort Seas stock) was 

 most heavily exploited between 1848 and 1915. This 

 is the largest surviving stock of bowhead whales. 

 During spring whales from this stock migrate from 

 wintering areas in the northern Bering Sea to the 

 Chukchi and Beaufort Seas. There they spend much 

 of the summer before returning to the Bering Sea in 

 autumn. The bowhead whale is an important subsis- 

 tence resource for Alaska Natives who hunt them as 

 they migrate along the coast of Alaska in both spring 

 and fall. 



Bowhead whales are listed as endangered under the 

 Endangered Species Act and are considered depleted 

 under the Marine Mammal Protection Act. All stocks 

 of bowhead whales are classified as protected stocks 

 by the International Whaling Commission (IWC). As 

 such, commercial whaling quotas are set at zero; 

 however, under subsistence whaling provisions for 

 aboriginal hunters, limited catch quotas are recom- 

 mended by the IWC for the western Arctic stock of 

 bowhead whales. 



Factors such as environmental change, pollution, 

 and noise disturbance from activities related to off- 

 shore oil and gas exploration, combined with subsis- 

 tence take, could have a cumulative effect that might 

 hinder recovery of the western Arctic bowhead whale 

 stock. With regard to oil and gas activities, the 

 Marine Mammal Commission provided comments to 

 the Minerals Management Service in 1995 on a draft 

 environmental impact statement regarding a proposed 

 oil and gas lease sale in the Beaufort Sea. These are 

 described in Chapter IX. 



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