174 



itka Island, Alaska, to the aquarium. The new arrivals were an adult female, 

 two subadult females, and a subadult male. It may now be possible to obtain 

 additional information such as length of the gestation period and rate of growth 

 and development of young. 



Hurcau studies have develoi)ed methods of transporting and keeping sea otters 

 in captivity and have aided in the design of pools completed at the Point Defi- 

 ance A(iuarium in Taeoma. Washington, which now has the only facility in 

 the world built specifically for sea otters. The facility consists of two separate 

 enclosures, each having a pool. The big pool is 20 feet in diameter and 5 feet 

 deep, uith a capacity of H.OOO gallons ; the smaller pool is 14 feet in diameter 

 and 4V-' feet deep, and holds 2,000 gallons. Eighty gallons of filtered sea water, 

 partly fresh and partly recirculated, enters the two pools each minute. The 

 enclosures are connected by a passageway with doors that are used to con- 

 trol the location of the otters. The otters may be viewed from above or below 

 the surface. 



The sea otter in California 



The number of sea otters in California is increasing, according to the best 

 counts available, at a rate of about 5 percent a year. This rate is similar to that 

 of certain Alaskan populations. Al)out 1,014 sea otters were in California in 1969. 

 In future years, it seems probable sea otters will continue to spread into suitable 

 habitat within their former range. If the commercial abalone fishing is to con- 

 tinue at the present rate, the ix)pulation of sea otters will probably need to be 

 controlled in certain waters. 



WALRUS 



Current research on the walrus is confined to surveys in the Bering Sea (in- 

 cluding other marine mammals, also). Four aerial surveys of marine mammals 

 have been conducted in recent years in the Bering Sea and to the north in a small 

 southern portion of the Chukchi Sea. Results of the four surveys are being 

 analyzed. In general, they reveal concentrations of the mammals in certain 

 geographic areas in both national and international waters. There are other areas 

 where marine mammals rarely occur. Within the large zones used by marine 

 mammals, ice conditions influence local distribution and abundance. In recent 

 years the U.S.S.R. has shown increased interest in harvesting seals and walruses 

 on the ice floes. The growing scarcity of the ribbon seal and past experience with 

 walrus depletion indicate that proper harvesting of these species will require 

 additional knowledge and agreements between countries if they are to be con- 

 served as a renewable resource in international waters. 



MISCELLANEOUS 



In addition to the activities named above, research personnel of the Bureau, 

 located at the U.S. National Museum, are engaged in studies of taxonomy, dis- 

 tribution, mori)hology, and reproduction of various marine mammals. Most of 

 the specimens available for these modest studies are found stranded along the 

 Atlantic coast. 



Bureau personnel are active in studies of the Monk Seal, an endangered species 

 occurring in Hawaiian waters. 



Sea Otter Studies by Cooperative Wildlife Research Units 



BUREAU OF sport FISHERIES AND WILDLIFE 



Oregon Cooperative Wildlife Research Unit. — The Oregon Cooperative W^ild- 

 life Research Unit has undertaken a study to evaluate the initial success of 

 attempts to introduce sea otters into their former range along the Oregon coast. 

 This study will attempt to determine the distribution of tlie otters released in 

 1970 and will monitor the post-release movements and behavior of the otters re- 

 leased in 1971. Information will also be sought on reproduction, the habitats 

 favored by otters, and the foods utilized. 



Funding : $11,928.00, Division of Wildlife Research. 



Alaska Cooperative WildUfc Research Unit. — The Alaska Cooperative Wildlife 

 Research Unit has initiated a study on the ecology and behavior of sea otters 

 in Prince AVilliam Sound. This study will gather information on the feeding 

 behavior, diurnal and seasonal movements, activity patterns, and intraspecific 

 competition of sea otters in Prince William Sound, a possible termination point 

 of the Trans- Alaska Oil Pipeline. 



