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

Jonathon I Newkirk,Casey W Schoenebeck

doi:10.1080/02705060.2018.1473295

Jonathon I Newkirk, Casey W Schoenebeck

Open Access

https://doi.org/10.1080/02705060.2018.1473295

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Abstract

ABSTRACTWe 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).

Highlights

Slimy sculpins, Cottus cognatus, are an ecologically important benthic insectivore inhabiting lentic and lotic cold-water ecosystems throughout North America
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
Most macroinvertebrate taxa were consumed in proportion to their availability (¡0.15 < L > 0.15), Hydropsychidae were selected by slimy sculpins within two of the three investigated streams within the Lake Superior-North Watershed

Summary

Introduction

Cottus cognatus, are an ecologically important benthic insectivore inhabiting lentic and lotic cold-water ecosystems throughout North America. In cold-water lentic systems, slimy sculpin inhabit rocky littoral areas ranging from small headwater lakes to the Great Lakes. Lentic slimy sculpin have been found to primarily consume Gammarus spp. and feeding strategies have been found to be nocturnal (Brandt 1986), when Gammarus are most active. In addition to Gammarus, lentic slimy sculpins have been found to consume Opossum shrimp, Mysis relicta, and Diptera spp. Slimy sculpin inhabit low-order, cold-water streams with abundant cobble. Slimy sculpin have been found to primary consume Gammarus spp. Slimy sculpin selected Gammarus spp., and selected various sizes of Gammarus over other available prey (Filicky et al 2000)

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