Author

Earl

Date of Award

8-2005

Degree Name

Master of Science

Department

Biological Sciences

First Advisor

Dr. Steven L. Kohler

Second Advisor

Dr. Stephen B. Malcolm

Third Advisor

Dr. David P. Cowan

Access Setting

Masters Thesis-Open Access

Abstract

The relationships between predators and their prey are important and influential components in the structure of ecological communities. These interactions not only impact the species involved, but can also have a wide range of direct and indirect effects that resonate throughout the community. In Michigan trout streams, one of the main predators of benthic invertebrates is the mottled sculpin (Cottus bairdi) whose diet and selective predation may influence benthic invertebrate community structure. Using gastric lavage, the stomach contents of sculpins from both erosional and depositional habitats were collected and analyzed to determine the main prey types, prey preference, and habitat effects in the diet. Prey preference was determined using Chesson's α to calculate prey selectivity. The predatory effects on the benthic invertebrate community were examined using caging experiments. Habitat did significantly affect sculpin diet with the top three prey types being Ephemerella, Chironomidae, and Hydropsyche. The selectivity index showed that sculpins are generalist feeders, although they did significantly avoid prey types with low movement rates, case-building ability, and small size. The predatory effects of the sculpin diet did not significantly affect the benthic invertebrate community.

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Biology Commons

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