Effect of Increased Water Temperature on Warm Water Fish Feeding Behavior and Habitat Use

Global warming could cause changes in species behavior and life history. Stream fish may be significantly affected by climate change because individuals are restricted in their movements by water systems and other physical factors, preventing migration to locations more thermally suitable. The effect of warmer waters on stream fish could change behavior and affect the fish species survival and ultimately ecosystem function. During my experiment I observed the effects of increased water temperature on the feeding behavior and habitat use of two native Minnesota fish species, black crappie (Pomoxis nigromaculatus) and black bullhead (Ameiurus melas). An increase of 2oC over a period of 4 weeks resulted in a 35% decrease in the number of feeding events by black bullheads and an increase of 22.2% for black crappies. Significant changes in habitat use were also observed during the study, with bullheads increasing their use of open areas, plant cover, and swimming behavior, while decreasing their use of brick interior for cover and searching behavior. Crappies were found to increase their use of open areas and swimming behavior, while decreasing their use of the brick exterior for cover. These results provide insight about the future effects of increased water temperature on the feeding behavior, habitat use, and ecosystems of fish species.