Habitat Associations of Introduced Smallmouth Bass and Native Signal Crayfish of Lake Whatcom, Washington During November 1998

Little information exists concerning the impact of introduced smallmouth bass on native signal crayfish in Washington. Diver observations quantified the effects of habitat type on smallmouth bass and signal crayfish densities in a lake renowned for its smallmouth bass fishery. Relationships were examined between smallmouth bass density and signal crayfish density, but also between their densities and proportional substrate types including boulder/bedrock, gravel/cobble, silt/sand, submersed vegetation, and coarse woody debris. Although diver observations were consistent with previously demonstrated smallmouth bass-crayfish habitat associations, the impact of introduced smallmouth bass on native signal crayfish remains enigmatic. Still, the results should provide direction on ways to improve our understanding and management of predator and prey species alike.