Evaluation of Habitat Use by a Catch‐and‐Release Regulated Flathead Catfish Population in Branched Oak Reservoir, Nebraska, USA

Abstract

AbstractA series of rock jetty and A‐Jack structures was built in 1998 at Branched Oak Reservoir, Nebraska, in an attempt to reduce shoreline erosion and cove degradation. In conjunction with the habitat enhancement project, Flathead Catfish Pylodictis olivaris were stocked to help control the abundant White Perch Morone americana population. Previous research found that Flathead Catfish utilized the habitats created by the enhancement project; however, the research was conducted while the Flathead Catfish population was still developing and the reservoir water elevation was held for an extended period below conservation pool. We sampled three habitat types (rock jetty structures, concrete A‐Jack structures, and new‐growth trees) during the summer months from 2015 to 2019 using daytime low‐frequency electrofishing to determine differences in size distribution and relative abundance among habitat types. Flathead Catfish utilization of the rock jetty structures was characterized by high catch rates (137 fish/h) and smaller fish (<400 mm). Lower catch rates were found in the A‐Jack structures (86 fish/h) and new‐growth trees (36 fish/h); however, these habitats were primarily utilized by larger fish (>600 mm). Habitat use changed with the developing population and the availability of a new habitat type, inundated new‐growth trees. The catch‐and‐release regulation changed both density and size structure of the Flathead Catfish population in Branched Oak Reservoir. The results of this study can assist fisheries managers in locating or enhancing favorable reservoir habitats for Flathead Catfish.