MARINE MAMMAL COMMISSION - Annual Report for 1998 



The cost of maintaining these animals in captivity 

 has been a significant financial burden on the Service. 

 However, the possibilities that the condition could be 

 contagious, that the monk seals would be unable to 

 adapt to the wild and evade sharks after years in 

 captivity, have made it inadvisable to release them. 

 The Service therefore convened a review panel on 1-4 

 June 1997 to obtain advice and recommendations on 

 what to do with the seals and whether rehabilitation 

 work should be resumed. The panel included inde- 

 pendent experts in veterinary medicine, population 

 biology, and wildlife management. A report of the 

 panel's findings was circulated in June 1997. Among 

 other things, it recommended that the seals now in 

 captivity not be released and that the Service make 

 every effort to find a facility willing to care for the 

 animals and provide access to them for research. 



In light of the panel's recommendations, the 

 Service developed a plan, including a list of potential 

 facilities and transfer criteria, for moving the animals 

 now held in captivity to approved facilities for long- 

 term care. Based on discussions of these plans at the 

 Commission's November 1997 annual meeting, the 

 Commission wrote to the Service on 23 December 

 1997 urging that, if at all possible, the Service avoid 

 transferring the monk seals to a foreign facility 

 because of their importance for research and because 

 of the less rigorous husbandry and maintenance 

 standards found in some foreign facilities. The Com- 

 mission recommended that the Service increase efforts 

 to find a suitable U.S. facility to care for the animals. 



During the Commission's 10-12 November 1998 

 annual meeting, it was advised that an agreement has 

 been reached with Sea World of Texas, San Antonio, 

 for the permanent care and maintenance of all of the 

 captive monk seals. The Sea World facility is an 

 appropriate long-term husbandry facility that has the 

 capability to regulate the environment of the holding 

 facility and thereby alleviate potential sources of 

 stress. Also, the monk seals will be kept together as 

 a group and will be available for approved research 

 projects to obtain information that cannot be obtained 

 from wild animals. Pending final approval, the 

 transfer of these animals is expected in February 

 1999. By letter of 31 December 1998 the Commis- 

 sion commended the Service for its efforts to find a 

 suitable U.S. facility to accept the animals. 



Steller Sea Lion 

 (Eumetopias jubatus) 



Steller sea lions range along the rim of the North 

 Pacific Ocean from the Channel Islands in Southern 

 California to Hokkaido, Japan, with centers of abun- 

 dance in the Aleutian Islands and the Gulf of Alaska. 

 Although some individuals, particularly juveniles and 

 adult males, disperse widely outside the breeding 

 season (late May to early July), animals tend to return 

 to their natal rookery to breed. About three-fourths 

 of all Steller sea lions haul out and pup in U.S. 

 territory. Over the past 30 years, Steller sea lion 

 abundance has declined dramatically throughout most 

 of the central and western part of its range (Table 4). 

 Numbers of Steller sea lions at some sites have 

 declined by more than 80 percent since the mid- and 

 late 1970s, and the species has all but disappeared at 

 other sites (Figure 6). Because of this decline, in 

 1990 the National Marine Fisheries Service designated 

 the Steller sea lion as threatened under the Endan- 

 gered Species Act. 



The cause of the decline is uncertain, and may be 

 due to a number of factors. The most commonly held 

 hypotheses are that available prey species have de- 

 creased in abundance or that there has been a signifi- 

 cant change in prey species composition. Either may 

 have led to an increase in sea lion mortality, particu- 

 larly among juveniles. Steller sea lions are known to 

 prey upon a variety of species, including Atka mack- 

 erel, walleye pollock, salmon, herring, and flatfishes, 

 all of which are taken by commercial fisheries. The 

 extensive commercial fisheries in Alaskan waters 

 therefore may be a significant factor affecting prey 

 availability for Steller sea lions. Other possible 

 factors contributing to the species' decline include 

 incidental taking by foreign and joint-venture trawl 

 fisheries from the late 1960s to the late 1980s, human 

 disturbance at haul-out sites, deliberate shooting, a 

 commercial sea lion harvest in parts of Alaska from 

 the 1950s to the early 1970s, hunting in British 

 Columbia from the early 1900s to the early 1960s to 

 reduce predation on commercial fish stocks, subsis- 

 tence hunting by Natives in Alaska and Russia, and 

 environmental perturbations. 



56 



