The potential impact of sea otters (Enhydra lutris) on the British Columbia geoduck clam (Panopea abrupta) fishery

摘要

I used fishery-independent survey data and catch curve analysis to assess the potential predation effects of sea otters on the British Columbia geoduck fishery on the west coast of Vancouver Island, by estimating geoduck total mortality rates across a gradient of sea otter abundance. Linear regression provided strong evidence of a fishing effort effect on geoduck total mortality while the main effect of otters was not significant. Harvesters, however, have increasingly reported seeing sea otters eating geoduck; thus a more balanced study design and greater sampling intensity are needed to increase the power to detect whether sea otters affect geoduck harvests. This paper concludes with an examination of the different legislative mandates of fisheries and wildlife management in Canada, and establishes that artificially limiting the sea otter’s range in B.C. would be difficult under federal law and for socio-political reasons.