Use of Dead Mussel Shells by Madtom Catfish in the Green River

Jacob Brumley, Western Kentucky University

Document Type Thesis

Abstract

The Green River in Kentucky has high fish and macroinvertebrate diversity. As both fish and macroinvertebrates have evolved together in this system, symbiotic relationships have developed between species. One type of relationship that has been observed is between madtom catfish (Noturus spp.) and mussels in the Green River, as the madtom individuals use dead mussel shells as cover while not actively hunting. In the fall of 2016 and 2017, surveys were conducted to determine if madtom catfish prefer hiding under dead mussel shells or rocks of similar size. The data was collected at four separate sites along the Green River, each sampled per year. Three 12-meter by 12-meter plots were sampled at each site by snorkeling upstream searching for madtoms in the dead mussel shells and under the rock substrate. An equal amount of effort was used searching for madtoms under rocks and in mussel shells. Significantly more madtoms were found under mussel shells than under rocks of similar size. These results support the hypothesis tested in this study that madtoms prefer the cover of mussel shells rather than rocks. The decline of mussel populations, and resulting decline in available mussel shells in rivers and streams, may have negative effects on madtom populations in the future.