1999 

 OUR LIVING OCEANS 



Population 

 (X 1.000) 



140 - 



120 - 



100 - 



80 - 



60 - 



40 - 



20 - 



- 



1960s 

 (decade average) 



1970's 

 (decade average) 



Western U S Pacific stock ~ 



Eastern Pacific stock 



U S total 



Year 



ern Pacifii; stock of 30,400 is used as a miiiimiim 

 because animals not seen in the surveys have not 

 been taken into account. 



Figure 22-1 



Estimated population size of 

 Steller sea lions (adults, ju- 

 veniles, and pups) of tfie two 

 stocks off ttie United States 

 and Canada. 



Current Population Trend 



Western U.S. Pacific Stock — Ihe first reported 

 trend counts (an index of population size) of Steller 

 sea lions in Alaska were made durini; 19S6-60 

 which indicated that there were at least 140,000 

 sea lions in the Clulf of Alaska and Aleutian Is- 

 lands. Subseqtient surveys indicated a major popu- 

 lation decrease, first detected in the eastern Aleu- 

 tian Islands in the mid 1970s. The decline ap- 

 peared to have spread eastward to the Kodiak Is- 

 land area during the late 1970's and early 1980's, 

 and then wesrward to the central and western Aleu- 

 tian Islands during the early and mid 1980's. The 

 greatest declines occurred in the eastern Aleutian 

 Islands and western Gull of Alaska, but declines 

 also occurred in the central Gulf of Alaska and 

 central Aleutian Islands. Uncorrected counts from 

 1976-79 indicated about 104,000 ,sea lions. The 

 western U.S. Pacific stock decreased 37.4'!''o from 

 1 989 to 1 994. The 1 994 estimate was 42,S36 ani- 

 mals, and the 1996 estimate was 39,S()(). 



2,000-3,000 animals (Figure 22-1). The counts 

 in Oregon have shown a gradual increase since 

 1 976, as the adult and juvenile count for that year 

 was 1,486 compared to 3,522 for 1994. This in- 

 crease is likely due to a recovery from reduced 

 numbers caused bv mortality prior to 1972, as im- 

 migration from other areas has not been docu- 

 mented. Cxnints in (California declined by over 

 50% from 5,000-7,000 berween 1927 and 1947 

 to 2,000-2,500 berween 1980 and 1990; limited 

 information suggests that counts in northern Cali- 

 fornia have increased from the late 1970's to the 

 early 1990's. At Ano Nuevo, California, a steady 

 decline in ground counts started around 1 970, re- 

 sulting in a 85'Ko reduction in the breeding popu- 

 lation by 1987. Based on data from vertical pho- 

 tography taken between 1990 and 1993, pup num- 

 bers declined at a rate of 9.9%, while older indi- 

 viduals declined at a rate ot 31.5%. Most recently, 

 population estimates tor Steller sea lions in the 

 eastern Pacific stock increased 5.8% from 1989 

 (22,600) to 1994 (23. 'S33) an increase that ap- 

 parenth' is continuing. 



Stock Status 



The PBR tor the western U.S. Pacific stt)ck of 

 Steller sea lions has been estimated at 350 animals 

 and lor the eastern Pacific stock at 1 ,368. 1 he es- 

 timated annual level of total human-caused mor- 

 tality and serious injury was 443 animals lor the 

 western U.S. Pacific stock and 16 tor the eastern 

 Pacific stock, rhe mortalities lor the western U.S. 

 Pacific stock exceed this stock's estimated PBR. 

 Both stocks of Steller sea lion are currently listed 

 under the PSA; the western U.S. Pacific stock is 

 listed as endangered, and the eastern Pacific stock 

 is listed as threatened. Thus, both stocks ol Steller 

 sea lions are classified as strategic stocks. Manage- 

 ment actions recently implemented to reduce in- 

 teractions with human activities include no-entry 

 bufler zones around rookeries, prohibition ot 

 groundfish trawling within 10 20 iiautiL.il miles 

 of certain rookeries, and spatial and tempt)ral al- 

 location of Gulf of Alaska pollock catches. 



Eastern Pacific Stock — Trend counts lor the east- 

 ern Pacific stock have been relatively stable at about 



232 



