MARINE MAMMAL COMMISSION - Annual Report for 1998 



To further evaluate and refine this research tech- 

 nique for purposes of monitoring trends in the status 

 of the Pacific walrus population, a survey similar to 

 those conducted in the early 1980s was undertaken in 

 September 1998. It was conducted by personnel from 

 the University of Alaska and the Fish and Wildlife 

 Service with funding from the National Fish and 

 Wildlife Foundation and using an ice-breaking vessel 

 made available at no charge by Greenpeace. The 

 survey involved a 17-day cruise along the ice edge of 

 Chukchi Sea between Barrow, Alaska, and Wrangel 

 Island, Russia, and along the coasts of the Chukotka 

 Peninsula and northwestern Alaska. 



During the survey, the ages and sex of approxi- 

 mately 1,000 walruses were determined. Preliminary 

 findings indicate that only about 5 percent of the 

 mature females were accompanied by yearlings and 

 that another 5 percent were accompanied by year-old 

 animals. The results suggest that, for at least the past 

 two years, either the number of births or the survival 

 of young animals has been very low — a finding that 

 is consistent with observations by Native hunters who 

 reported observing very few calves during the spring 

 1998 hunt. At the end of 1998 a report of survey 

 results had not yet been completed. 



Most walrus calves remain with their mothers two 

 or three years after birth, and mature females typically 

 give birth once every two or three years. Thus, 

 potential population growth rates are low compared 

 with those of most pinnipeds that give birth annually, 

 and juvenile walrus survival rates are much higher 

 than those of most pinnipeds. With such a life 

 history, the limited information on the population size 

 and trends, and uncertainty as to when recruitment 

 rates may have first declined, the preliminary indica- 

 tion of at least two successive years of poor recruit- 

 ment into the population is of concern. As a possibly 

 related matter, warm temperatures in 1998 caused 

 pack ice in the Chukchi Sea to retreat farther north 

 than past years. Low reproductive rates and/or juve- 

 nile survival could be related at least in part to this 

 climatic change. 



If funding is available, researchers plan to conduct 

 a similar survey in 1999. 



Polar Bear 

 (Ursus maritimus) 



Polar bears occur throughout the Arctic region in 

 several largely discrete stocks that are shared between 

 countries. The species can be found within the 

 national boundaries of the United States, Canada, 

 Greenland, Norway, and Russia, as well as in interna- 

 tional waters. The total population has been estimated 

 at 21,000 to 28,000 animals. Two polar bear popula- 

 tions occur in Alaska: the western Alaska (Chuk- 

 chi/Bering Seas) population, which is shared with 

 Russia; and the northern Alaska (southern Beaufort 

 Sea) population, shared with Canada (see Figure 10). 

 The total number of polar bears in Alaska and adja- 

 cent waters is estimated at 2,000 to 5,000 animals. 



Both the Chukchi/Bering Seas stock and the Beau- 

 fort Sea stock may have declined as a result of sport 

 hunting that occurred before enactment of the Marine 

 Mammal Protection Act in 1972. The stock assess- 

 ment issued by the Fish and Wildlife Service in 

 September 1998, and discussed below, suggests that 

 both stocks have grown as a result of protection 

 provided by the Act. However, it has been difficult 

 to obtain accurate estimates of the current and historic 

 size of the populations because of inaccessibility of the 

 habitat, the movement of bears across international 

 boundaries, and the costs of conducting surveys. 



Until the middle of this century, polar bears in 

 Alaska were taken primarily by Natives for subsis- 

 tence purposes and for the sale of hides. Beginning 

 late in the 1940s a sport hunt developed that involved 

 trophy hunters using professional guides to hunt 

 animals, sometimes with the use of aircraft. As a 

 result, hunting pressure on polar bear populations in 

 Alaska and elsewhere increased substantially. Recog- 

 nizing this, the State of Alaska adopted regulations in 

 1961 to restrict the sport hunting season and require 

 hunters to present all polar bear skins for tagging and 

 examination. At the same time, preference was 

 provided to subsistence hunters and a prohibition was 

 adopted on shooting cubs and females with cubs. 

 Between 1961 and 1972 an average of 260 polar bears 

 was taken annually in Alaska, 75 percent of which 

 were males. In 1972 the state banned hunting with 

 the use of aircraft. 



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