Meeting Abstract
Anthropogenic habitat alteration disturbs fishes at the community and organismal levels, but effects are seldom related to the physiological processes. Metabolism is the most basic rate which may govern organismal life history and behavior, and can help explain ecological interactions of fish. We examined the energetics and distribution of Longear Sunfish, Lepomis megalotis, within Kickapoo Creek, Illinois. This is a region of decreased geomorphic stability and the site of multiple stream restoration projects. We sampled Longear Sunfish using pulsed DC barge electrofishing to examine patterns in abundance and distribution along a gradient of habitat conditions. Fish were then brought to the lab where we measured metabolic oxygen consumption using intermittent-flow respirometry during steady swimming. Fish were observed in laminar and turbulent flows to examine effects on performance. Simulated turbulence consisted of three horizontal streets of vortices, each similar in size produced by equally spaced vertical cylinders with diameters similar to fish depth. We found greater metabolic costs of swimming in turbulent flows than in a quasi-laminar regime. Significant regression models on habitat parameters linked distribution of Longear Sunfish to proportions of pool area, silt, sand and boulder substrate, and instream cover variables. Ecomorphological models for Longear Sunfish suggest that increased metabolic demands associated with navigating turbulent flows may help explain habitat use and behavior. Longear Sunfish show fidelity to areas of low flow and turbulence which also contain multiple types of instream cover such as overhanging riparian vegetation and woody debris.
