Volume 1 Pages 1 - 23 (May 1986)

Citation: Stenson, G.B. (1986) The Status of the Sea Otter in Canada.  IUCN Otter Spec. Group Bull. 1: 13 - 14

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The Status of the Sea Otter in Canada

G.B. Stenson

Fisheries Research Branch, Department of Fisheries and Oceans, St. John's, Newfoundland, Canada.

Two species of otters occur in Canada. The sea otter, Enhydra lutris , is found along the Pacific coast while the river otter, Lutra canadensis , is distributed over most of the country. The history and current status of these two species differ-greatly. This is the first of two reports of otters in Canada. In this report I will examine the status of the sea otter while in the subsequent report I will deal with that of the river otter .

The sea otter inhabits the coastal waters of the northern Pacific Ocean. Historically its range extended along the west coast of North America from Baja California Mexico to Alaska, across the Aleutian Islands to the Kamchatka Peninsula and south to the northern islands of Japan (Kenyon, 1982). In Canada, it: probably inhabited the entire outer coast of British Columbia, especially along Vancouver Island and the Queen Charlotte Islands (Munro, 1985). During the 18th and 19th centuries the sea otter was hunted extensively for its rich fur. This heavy exploitation resulted in the sea otter being extirpated from most of its former range, including all of Canada, by the early 1900's. Viable populations of sea otters were restricted to Alaska and California only. To halt this decline Great Britain (for Canada), Japan, Russia and the United States signed an international treaty to protect the sea otter in 1911.

In the late 1960's a programme was initiated to reintroduce sea otters into Canada. Between 1969 and 1972 a total of 89 otters were taken from Alaska and released along the west coast of Vancouver Island. The first reliable estimate of the status of this population was made in 1977 when 70 otters were observed (Bigg and MacAskie, 1978). By 1984 this number had risen to 350 animals (Bigg, pers. comm.) which indicates that the population is well established. The majority of the population appears to be confined to the region of the original transplant but sightings from other areas are becoming more frequent. This suggests that the population is dispersing to some extent.

In Canada, the sea otter is protected by both the Federal Fisheries Act and the British Columbia Wildlife Act. In 1976 it was declared endangered by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) and in a recent meeting this status was reconfirmed. International trade in sea otters is controlled by the Convention on International Trade in Endangered Species (CITES) which Canada signed in 1975. Because the original transplants were from Alaska, the Canadian population is classified as Enhydra lutris lutris and is listed on Appendix II of CITES rather than Appendix I as is Enhydra lutris nereis. Appendix II does not prohibit trade but does allow for the monitoring of trade of sea otters across Canadian borders. To date, trade in sea otters in Canada has been extremely limited (Heppes, pers. comm.) and considering the low population levels and the endangered status it is unlikely to increase significantly in the near future.

The current outlook for sea otters in Canada is optimistic. The extirpation of otters in Canada was caused by commercial exploitation and with continued protection it is likely that the population will continue to increase. Suitable habitat appears to be plentiful and does not appear to have been reduced significantly in quantity or quality since historical times (Munro, 1985). Given the remoteness of much of this habitat it is unlikely that human activities pose much of a threat at the present time. One possible exception, however, is the presence of oil pollution. Unlike most marine mammals, sea otters rely upon their fur for insulation. This fur is highly sensitive to environmental contamination and oiling has been shown to significantly reduce its insulative properties (Costa and Kooyman, 1982). This results in increased metabolic rates and can cause death. Considering the limited distribution of sea otters and the increased interest in offshore oil development and transportation along the British Columbian coast, this could pose a future threat. For now however, the future of sea otters in Canada appears bright.

References

Bigg, M. A. and I. B. MacAskie (1978) Sea otter established in British Columbia. J. Mamm. 59: 874-876.

Costa, D. P. and G. L. Kooyman (1982) Oxygen consumption, thermoregulation, and the effect of fur oiling and washing on the sea otter, Enhydra lutris. Can. J. Zool..60: 2761-2767.

Kenyon, K. W. (1982) Sea otter. In: Chapman, J. A. and G. A. Feldhamer (eds.). Wild Mammals of North America: Biology, Management, and Economics. John Hopkins Univ. Press, Baltimore, MD. pp. 704-710.

Munro, Wai. T. (1985) Status of the sea otter, Enhydra lutris, in Canada. Can. Field-Nat. 99: 413-416.

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