Modeling the Relations Between Flow Regime Compone

Authors: Scott W Craven James T Peterson Mary C Freeman Thomas J Kwak Elise Irwin

Publish Date: 2010/06/18

Volume: 46, Issue: 2, Pages: 181-194

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Abstract

Modifications to stream hydrologic regimes can have a profound influence on the dynamics of their fish populations Using hierarchical linear models we examined the relations between flow regime and youngofyear fish density using fish sampling and discharge data from three different warmwater streams in Illinois Alabama and Georgia We used an information theoretic approach to evaluate the relative support for models describing hypothesized influences of five flow regime components representing shortterm high and low flows shortterm flow stability and longterm mean flows and flow stability on fish reproductive success during fish spawning and rearing periods We also evaluated the influence of ten fish species traits on fish reproductive success Species traits included spawning duration reproductive strategy egg incubation rate swimming locomotion morphology general habitat preference and food habits Model selection results indicated that youngofyear fish density was positively related to shortterm high flows during the spawning period and negatively related to flow variability during the rearing period However the effect of the flow regime components varied substantially among species but was related to species traits The effect of shortterm high flows on the reproductive success was lower for species that broadcast their eggs during spawning Species with cruiser swimming locomotion morphologies eg Micropterus also were more vulnerable to variable flows during the rearing period Our models provide insight into the conditions and timing of flows that influence the reproductive success of warmwater stream fishes and may guide decisions related to stream regulation and managementA number of people were instrumental in providing assistance with this project We are particularly indebted to the many technicians volunteers and graduate students who conducted the field portions of this study including TM Skelly the late MJ Sule and CShea Funding for this analysis was provided by the US Geological Survey through the National Park Service Science Support Program The manuscript was improved with suggestions from CR Jackson J Long and anonymous reviewers The use of trade product industry or firm names or products is for informative purposes only and does not constitute an endorsement by the US Government or the US Geological Survey The Georgia Cooperative Fish and Wildlife Research Unit is sponsored by the US Geological Survey the US Fish and Wildlife Service the Georgia Department of Natural Resources the University of Georgia and the Wildlife Management Institute The North Carolina Cooperative Fish and Wildlife Research Unit is sponsored by the US Geological Survey the US Fish and Wildlife Service the North Carolina Wildlife Resources Commission North Carolina State University and the Wildlife Management Institute The Alabama Cooperative Fish and Wildlife Research Unit is sponsored by the US Geological Survey the US Fish and Wildlife Service the Alabama Department of Conservation and Natural Resources Auburn University and the Wildlife Management Institute

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