Modeling Habitat Selection of a Top Predator: Considering Growth and Physical Environments in a Spatial Context

Abstract

Mechanisms associated with habitat selection by fishes are often unknown and require both physical habitat and growth environment considerations. We used spatially explicit prey biomass estimates, predator growth rate potential (GRP), bottom slope, predator distance from shore, and substrate data to predict habitat use of the saugeye (walleye Sander vitreus × sauger S. canadensis), a popular sport fish that is stocked throughout the central United States. We used telemetry to determine saugeye locations, acoustics to estimate prey biomass and distributions, and a bioenergetics model to aid in calculation of GRP. Akaike's information criterion was used to determine which habitat variables were most important in explaining saugeye location. Models that included both physical habitat and either GRP or prey density performed better than models that considered only one of these parameter types. The resulting models provided the data to create location suitability maps. In general, saugeyes favored steep slopes over hard substrates in nearshore areas with high biomass of gizzard shad Dorosoma cepedianum or high GRP. This comprehensive analysis suggests that the consideration of both spatial habitat suitability and temporal prey availability may improve fisheries management and conservation through a quantitative appreciation of available resources.

Received September 9, 2010; accepted August 23, 2011

ACKNOWLEDGMENTS

This manuscript was greatly improved by the feedback of three anonymous reviewers, and we thank them for their time and effort. We also thank J. Cudney, A. Gascho Landis, and C. Aman for their assistance in the field and laboratory. Thanks are extended to ODOW District 1 and the ODOW Inland Fisheries Research Unit for assistance in field sampling. We are grateful to E. Venteris for help with geostatistics and to D. Degan (Aquacoustics, Inc.) for providing insight into the analysis of acoustics data. Funding for this research was provided by the Federal Aid in Sport Fish Restoration program (Project F-69-P; Fish Management in Ohio) via the ODOW.