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

Global change is a major topic in today‘s society and a change in global temperature could cause a negative effect on biological species. Stream fish are thought to be significantly affected by climate change because individuals are restricted in their movements by water systems and other physical factors that would keep them from moving to locations that are more thermally suitable. The effect of warmer waters on stream fish could cause a change in behavior that could affect the survival of fish species and the ecosystem. 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 average increase of 2.3oC over a period of approximately 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 observed during the study, with bullheads increasing their use of open areas and plant cover, while decreasing their use of brick cover. Crappies were found to increase their use of open areas, while decreasing their use of the brick exterior for cover. These results may help to give an indicator about the future effects of increased water temperature on the feeding behavior, habitat use, and ecosystems of fish species