UNIT 22 

 MARINE MAMMALS OF THE ALASKA REGION 



Population Size 



All stocks ot bowhead whales were severely 

 depleted during intense commercial whaling prior 

 to the 20th century, starting in the early I6th cen- 

 tury near Labrador and spreading to the Bering 

 Sea in the mid 19th century. Prior to commercial 

 whaling, the minimum world wide population 

 estimate was 50,000 animals, with 1 0,400-23,000 

 in the western Arctic stock. This population 

 dropped to less than 3,000 when commercial whal- 

 ing on this stock ceased at the end of the 19th 

 century (Figure 22-3). 



Since 1978, bowhead whales have been 

 counted from sites on sea ice north of Point Bar- 

 row during the whales" spring migration. These 

 counts have been corrected for whales missed due 

 to distance offshore (through acoustical locators), 

 whales missed when no watch was in effect (based 

 on sighting rates), and whales missed during a 

 watch (estimated as a function ot visibility, num- 

 ber of observers, and distance offshore). However, 

 in some years a small proportion ot the popula- 

 tion may not migrate past Point Barrow in the 

 spring, therefore the estimate could be negatively 

 biased. In 1993, unusuallv good counting condi- 

 tions resulted in what is considered to be the most 

 accurate population estimate to date for this stock: 

 8,200 bowhead whales (CV = 0.069), with a 95% 

 confidence interval trom 7,200 to 9,400. 



Minimum Population Estimate 



Using the population estimate (N) of 8,200 

 and its associated CV of 0.069, N tor the west- 



niin 



ern Arctic stock of bowhead whales is 7,738. 



Current Population Trend 



The western Arctic stock increased at a rate ot 

 3.1% (95% CI = 1.4-4.7%) from 1978 to 1993, 

 when abundance increased trom approximately 

 5,000 to 8,000 whales. This rate of increase takes 

 into account whales that passed beyond the view- 

 ing range ot the observers. 



Landings 

 (X 1,000) 



Landings 



Population 

 (X 1,000) 



Population 



- 4 



- 2 



_L. 



_L_ 



_L. 



I 



I 



_L. 



-J_ 



1850 1860 1870 1880 1890 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 



Year 



Status of Stock 



The PBR tor this stock is 77 whales. The In- 

 ternational Whaling Commission (IWC) indepen- 

 dently established a quota for the number of bow- 

 head whales to be taken by subsistence hunters, 

 such that the number ot whales struck could not 

 exceed 68 in 1995, 67 in 1996, 66 in 1997, and 

 65 in 1998. The IWC determination takes prece- 

 dence over the U.S. PBR estimate tor the purpose 

 ot managing the Alaska native subsistence harvest. 

 The level ot human-caused mortalitv and serious 

 injury averaged over the past five years (49) does 

 not exceed the PBR (77) nor the IWC quota for 

 1998 (66). Bowhead whales ot the western Arctic 

 stock are listed as endangered under the ESA and 

 turther classified as a strategic stock. 



BELUGA WHALE: BEAUFORT SEA, 



EASTERN CHUKCHI SEA, EASTERN 



BERING SEA, COOK INLET AND 



BRISTOL BAY STOCKS 



Stock Definition and 

 Geographic Range 



Beluga whales are distributed throughout sea- 

 sonally ice-covered Arctic and subarctic waters ot 

 the Northern Hemisphere, and are closely associ- 

 ated with open leads and polynya in ice-covered 

 regions. Depending on season and region, beluga 



Figure 22-3 



Bowhead whale population 

 trend and catch history, 

 1848-1993. 



235 



