Capture Efficiency of Blue Catfish Electrofishing and the Effects of Temperature, Habitat, and Reservoir Location on Electrofishing-Derived Length Structure Indices and Relative Abundance

Current sampling methods for blue catfish Ictalurus furcatus are suspected of being strongly biased against preferred-length fish (≥762 mm in total length [TL]), making it difficult to accurately determine the species' population density and size structure. To understand this potential bias with respect to electrofishing, we conducted seasonal and habitat-specific sampling on three Oklahoma reservoirs using 15-pulse/s DC at the 100–1,000 V setting (the percent of range being adjusted to achieve 4-A output). Temperature, habitat, and reservoir section were analyzed to determine which variables were associated with the highest total catch per unit effort (CPUETotal), the CPUE of preferred-length blue catfish (CPUE762), and the relative stock density of preferred-length fish (RSD762). Total CPUE and CPUE762 were significantly higher when the water temperature was 18°C or more, but the variability increased as the temperature exceeded 28°C. Catch rates were significantly higher in the upper reservoir...