Effects of Aquatic Habitat Degradation on Hybridization between Bluegill and Green Sunfish

Jacob Wittman will present his honors presentation on Thursday (4/14) from 4 PM in 370 Kottman Hall. His presentation is Effects of Aquatic Habitat Degradation on Hybridization between Bluegill and Green Sunfish.
Faculty Advisor:  Suzanne Gray

Description of research: Over the past century, our developmental efforts have intensified the amount of habitat degradation that’s been induced onto urban streams. It is known that habitat degradation, in all senses, reduces the biodiversity that’s present. In aquatic settings, this is commonly done through hybridization of fish and general loss of available habitat. We chose to dive in deeper to investigate the effects that aquatic habitat degradation has on hybridization of fish. More specifically, the commonly found hybrid between Bluegill (Lepomis macrochirus) and Green Sunfish (Lepomis cyanellus). This study took place in the fall of 2015, throughout the stretch of our own urban river, the Olentangy River, from the existing low-head dam to the relatively recently removed low-head dam near 5th Avenue. The available habitat quality in our four study sites was measured using the Ohio EPA’s Qualitative Habitat Evaluation Index (QHEI) and was then compared to the relative abundances of Bluegill, Green Sunfish, and Hybrid Sunfish. Our results illustrated that a positive relationship existed between habitat quality and Bluegill abundances, and a negative relationship existed between habitat quality and Hybrid and Green Sunfish abundances. We were also able to possibly distinguish the habitat characteristics that drive the hybridization between these two species; these being stream sediment type, amount of in-stream cover, and the overall quality of the riffle present.