ABSTRACT Objective Blue Catfish Ictalurus furcatus have been stocked into many U.S. ecosystems to create novel trophy fisheries. However, high resource use overlap with resident fish populations could lead to interspecific density-dependent growth and thus impede the stocking goal of establishing a trophy fishery. To help assess this potential, we sought to characterize the trophic ecology of Blue Catfish and existing Channel Catfish I. punctatus in two Ohio reservoirs: one that contained populations of both species and one that contained a mature Channel Catfish population and a small, newly stocked Blue Catfish population. Methods We quantified diet composition, size-based differences in diet, diet overlap, and stomach fullness of both species using fish collected during the spring, summer, and autumn (autumn 2021–summer 2024). We compared these aspects of their trophic ecology between reservoirs and among seasons to identify potential sizes and seasons of highest overlap. Results Diet overlap between species was often high due to generalist feeding habits. During spring and autumn, Blue Catfish were more piscivorous than Channel Catfish in the reservoir where they co-occurred. By contrast, Channel Catfish piscivory was higher in the reservoir with the small Blue Catfish population. During the summer, a season with high diet overlap, both species consumed more benthic macroinvertebrates and had less biomass in their stomachs relative to other seasons. Conclusions Owing to shared prey resources, particularly between large Channel Catfish and all sizes of Blue Catfish during summer, the potential for interspecific competition exists. This finding indicates the potential for dense populations of Channel Catfish to hinder trophy Blue Catfish production. Our results highlight the need for population-level modeling and experimental studies designed to better quantify competitive interactions that might reduce the production potential of both species’ fisheries.
Bentley et al. (Tue,) studied this question.