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SFS Annual Meeting

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ASSESSMENT OF TROPHIC INTERACTIONS AND DIETARY OVERLAP BETWEEN SMALLMOUTH BASS AND BROWN TROUT IN A PENNSYLVANIA STREAM

Climate change is predicted to affect the distribution of fish, leading to novel species interactions and shifts in trophic position. Smallmouth bass (Micropterus dolomieu), for instance, are in some areas expanding their range upstream and competing with cold water species. The purpose of our study was to determine the potential for competition between smallmouth bass and wild brown trout (Salmo trutta) using diet and stable isotope analysis. Diet items were obtained from 41 fish using gastric lavage, enumerated and categorized to the lowest taxonomic resolution possible (family or order), then analyzed using non-metric multidimensional scaling (NMDS). Fin clips were obtained from 29 brown trout and 26 smallmouth bass fish, dried and homogenized, and will be analyzed for 13C and 15N stable isotopes. Analysis of diet items shows little diet overlap between bass and trout, but nearly complete overlap between stocked and wild trout. Isotope analysis is expected to clarify ontogenetic changes in trophic role for each fish species. We anticipate our findings will be of interest of fisheries managers where brown trout and smallmouth bass may increasingly co-occur due to changing water temperature

Devin McClain (Primary Presenter/Author,Co-Presenter/Co-Author), Indiana University of Pennsylvania , ttfw@iup.edu;


Eli Beal (Co-Presenter/Co-Author), Indiana University of Pennsylvania, vyvt@iup.edu;


David Janetski (Co-Presenter/Co-Author), Indiana University of Pennsylvania, janetski@iup.edu;