Oiii Liviiii; Rcsiiiirces — Alaska 



i55 



Washington 



In 1969 and 1970, 59 sea otters were 

 released along the outer eoast of Washington. 

 Mortality was high, with 16 carcasses recovered 

 after the first release (Jameson et al. 1982). 

 Between 1977 and 1993, the population grew at 

 an average of about 20% per year. Between 

 1989 and 1993, however, the average annual 

 growth rate has been lower (12%). Unoccupied 

 habitat currently occurs north, south, and with- 

 in the present range, and continued growth is 

 likely. 



Predicted Trends 



Sea otters illustrate the healthy recovery of a 

 species following protection and active man- 

 agement. Rates of increase in most populations 

 with unoccupied habitat available to them have 

 been l7%-20% per year (Estes 1990a). As 

 unoccupied habitats become limiting, however, 

 density-dependent mechanisms may dramati- 

 cally reduce sea otter abundance. As geograph- 

 ically separate populations reach equilibrium 

 densities or as populations become so large as 

 to create long dispersal distances to unoccupied 

 habitats, we anticipate declining growth rates, 

 increased mortality, and numbers of otters sta- 

 bilizing near an equilibrium density. The 

 observed trend in virtually all persisting popula- 

 tions since 1911 has been one of growth, with 

 declines observed only as populations exceeded 

 available resources (Estes 1990a, 1990b). 

 Continued growth is expected, pailicularly in 

 Washington and southeast Alaska and along the 

 Kamchatka Peninsula. 



The long-term exponential growth in many 

 sea otter populations has allowed us to describe 

 the process of sea otter recovery. However, as 

 populations attain equilibrium densities and 

 growth rates decline, evaluation of future trends 

 will become more difficult. In addition, possi- 

 ble short-term changes, such as those resulting 

 from human impacts, may remain difficult to 

 detect. Thus, describing future population 

 trends will require improved population- or 

 individual-based assessment models. 



At least two issues are currently relevant to 

 sea otter conservation and management. One is 

 competition between sea otters and humans for 

 shellfish resources. As otters continue to reoc- 

 cupy former habitat, the commercial, recre- 

 ational, and subsistence harvest of species such 

 as crabs (Crustacea), clams (Bivalvia), abalone 

 (Gastropoda), and urchins, can be expected to 

 decline. 



Another cunent issue is the extent of the 

 legal and illegal harvest for sea otter fur. Both 

 the legal harvest by Alaska Natives and an ille- 

 gal harvest in Russia have recently increased 



(A. Burdin, Russian Academy of Science, per- 

 sonal communication). Reasonable harvest 

 guidelines and adequate inventory and monitor- 

 ing programs should be established in areas 

 with harvested populations. 



Neither of these conservation issues current- 

 ly appears to be precluding the continued 

 growth of sea otter populations, but the poten- 

 tial to overharvest this species has been well 

 demonstrated. Conservative management 

 should ensure continued growth through com- 

 plete recovery. 



References 



Burdin, A.M.. V.V. Vertyankin. and V.S. Nikiilin. Currenl 

 status of the sea otter population at Bering Island, 

 Commander Islands, Russia. In G.R. Vanhlarieom. ed. 

 Third Joint U.S./Russia Sea Otter Workshop, 

 Petropavlsk-Kamchatski. September 1991. Biological 

 Rep- In press. 



Estes. J. A. 1990a. Growth and equilihnum in sea otter pop- 

 ulations. Journal of Animal Ecology 59:38.')-40I. 



Estes. J. A. 1990b. Action plan for sea otters. In R Foster- 

 Turley. S. MacDonald. and C. Mason, eds. Otters: an 

 action plan for their conservation. Chicago Zoological 

 Society. Brookfield. IL. 



Estes. J. A., and G.R. VanBlaricom. 1985. Sea otters and 

 shellfisheries. Pages 187-235 in R. Beverton, J. 

 Beddington, and D. Lavigne, eds. Conflicts between 

 marme maiumals and fisheries. Allen and Unwin. 

 London. England. 



Irons, D.B., D.R. Nysewander. and J.C. Trapp. 1988. Prince 

 William Sound sea otter distnbution in relation to popu- 

 lation growth and habitat type. U.S. Fish and Wildlife 

 Service. ^\ pp. (Unpublished rep.) 



Jameson. R.J. 1993. Results of the 1992 survey of the 

 translocated sea otter population off the outer coast of 

 Washington State. International Union for the 

 Conservation of Nature and Natural Resources, Otter 

 Specialist Group Bull. 8:2-4. 



Jameson, R.J.. K.W. Kenyon. S. Jeffries, and G.R. 

 VanBlaricom. 1986. Status of a translocated sea otter 

 population and its habitat in Washington. The Murrelet 

 67:84-87. 



Jameson. R.J.. K.W. Kenyon. A.M. Johnson, and H.W. 

 Wight. 1982. History and status of translocated sea otter 

 populations in North America. Wildlife Society Bull. 

 10:100-107. 



Bering Island, Russia 



Olympic Peninsula. Washington 



Year 



Fig. 2. Growth patterns observed 

 in three sea otter populations in the 

 north Pacific resulting from natural 

 range expansion (Bering Island 

 and Prince William Sound) or 

 translocation (Washington). 



Sea ollci [Liilivdra liitris). 



