Spring Diet of River Otters, Lontra Canadensis, in the San Juan Islands of Washington State

Abstract

Lontra canadensis, the river otter, is a predator in marine nearshore ecosystems in North America. Because it is a top carnivore, L. canadensis, may be exerting a trophic cascade. Its diet can vary regionally and possibly seasonally. This study examines the diet of L. canadensis through feces analysis from two sites on San Juan Island, WA. Fishes and crustaceans were found to be the main prey items, and there was evidence that relative proportions of different prey types differ with location.