Prey electivity of the slimy sculpin within the Lake Superior-North Watershed

Abstract

We evaluated the prey electivity of lotic slimy sculpin (Cottus cognatus) within the Lake Superior-North Watershed, an area characterized by high gradient streams and lacking the preferred prey of Gammarus. Fish and macroinvertebrates were sampled at 67 sites within 52 rivers and streams during 2013 in the Lake Superior-North Watershed by the Minnesota Pollution Control Agency. Fish sampling was conducted with the use of backpack and stream tote barge electrofishers, and macroinvertebrates were collected using qualitative multi-habitat sampling within D-Frame kick nets. Feeding electivity was calculated using Strauss’ modified feeding electivity model for three rivers. In total we sampled 174 slimy sculpins within the Lake Superior-North Watershed and found sculpins positively selected for Hydropsychidae (47.3% of total taxa consumed) and Perlidae (11% of total taxa consumed) instead of abundant Chironomidae (20% of total taxa sampled).

Keywords

• Slimy sculpin
• prey electivity
• food habits
• Lake Superior
• lotic