Midwest Fish & Wildlife Conference 2016

AUTHORS: David Coulter, Department of Forestry and Natural Resources, Purdue University; James Breck, Institute for Fisheries Research, Michigan Department of Natural Resources, School of Natural Resources and Environment, University of Michigan; Cary Troy, School of Civil Engineering, Purdue University; Maria Sepúlveda, Department of Forestry and Natural Resources, Purdue University; Tomas O. Höök, Department of Forestry and Natural Resources, Purdue University

ABSTRACT: Warm water discharges are a common component of many waterways that create thermally dynamic environments across both space and time. Such thermal variability has potentially strong influence on the physiology, ecological interactions, and population trajectories of fishes. The realized responses of fish to these environments are expected to be mediated by their behavior, and specifically their differential utilization of various thermal habitats. While annual field surveys and tagging studies provide information on distributions and individual movement patterns, they generally only provide snapshots of distributions and movements of few individuals, and do not explicitly evaluate the behavioral mechanisms underlying distributional patterns. To this end, we designed a spatially-explicit individual-based model to evaluate movements and spatial distributions near thermal effluents for two fish species with differential thermal preferences; smallmouth bass and saugeye. We used observed water temperatures near the Tanners Creek power plant on the Ohio River to calibrate an existing thermal model (CORMIX) and predict the three-dimensional thermal plume downstream from the plant. Prey consumption and growth of each fish species (represented as super-individuals) were predicted using species-specific bioenergetics models. To consider the consequences of movement rules and select the most appropriate set of rules for future scenarios, we performed simulations where individuals were assigned a variety of movement rules and compared the resulting distribution patterns for both species. Modeling fish movements near industrial discharges will complement field studies and provide for more effective management of fish populations that are potentially directly influenced by anthropogenic activities.