In British Columbia, expanding sea otter (Enhydra lutris) populations are creating concerns among commercial
harvesters about the potential predation impacts on exploitable geoduck clam (Panopea abrupta) stocks. We analysed
fishery-independent surveys of exploited geoduck clam populations along a gradient of sea otter occupancy on the west
coast of Vancouver Island, British Columbia, Canada to assess relationships between otter presence, commercial fishery
removals of geoduck, and geoduck population demographics. Geoduck mean density, age composition, and estimated total
mortality were influenced by a combination of variables, and therefore, we could not differentiate among geoduck
populations according to sea otter presence or absence alone. As expected, we found a strong association between commercial
fishery removals and geoduck clam total mortality rates. In contrast, the local numbers of sea otters were not an
important factor affecting geoduck total mortality. A more balanced study design and greater sampling intensity would increase
the power to detect whether sea otter predation affects harvestable geoduck stocks. Also, knowledge of the consumption
rate by sea otters of geoduck throughout the year, in combination with survey data of unfished geoduck populations,
would facilitate better prediction of how geoduck clam mortality rates might change as sea otters re-colonise new
areas.
Archaeological mitogenomes illuminate the historical ecology of sea otters (
Enhydra lutris
) and the viability of reintroduction