Assessing Potential Instream Flow Impacts on the Fishes of Baron Fork Creek, Oklahoma

W. Jason Remshardt¹ and William L. Fisher²
Oklahoma Cooperative fish and Wildlife Research Unit 404 Life Sciences West Oklahoma State University Stillwater, Oklahoma 74078 (Voice) 405-744-6342 (Fax) 405-744-5006,¹remshar@okstate.edu, ²wfisher@okstate.edu

Keywords: IFIM; PHABSIM; fish habitat-use guilds; smallmouth bass

We used the Instream Flow Incremental Methodology (IFIM) and Physical Habitat Simulation System (PHABSIM) to model habitat-discharge relationships with habitat-use guilds for the fish assemblages in Baron Fork Creek, Oklahoma. The objectives of this study were to model these relationships with both the smallmouth bass population and the entire fish assemblage. Mesohabitat typing indicated that mid-channel pools comprised the largest area of habitat types in our study site (37.1%), followed by runs (23.1%), lateral pools (21.4%) riffles (16.3%), and backwater (7.0%). Microhabitat analysis of depth, velocity, substrate, and cover variables in all 5 habitat types was conducted and compared with habitat suitability criteria obtained at the site. We then identified microhabitat associations of all fish species collected at the site to identify habitat-use guilds. Our hypothesis is that riffle, nearshore run, and nearshore pool habitats will be most affected by reductions in flow. These reductions will likely negatively impact fishes in these habitats. PHABSIM modeling will be used to verify this hypothesis.