Habitat use and diet overlap of Blue Catfish and Channel Catfish populations in two northeastern Kansas reservoirs

Abstract Objective Blue Catfish Ictalurus furcatus have been widely stocked across the Midwestern and eastern United States, raising concerns about their potential competitive and predatory effects on other species, particularly Channel Catfish Ictalurus punctatus, which possess similar life histories and feeding strategies. We hypothesized that increasing Blue Catfish abundance in Kansas reservoirs would lead to increased overlap of dietary and space use with Channel Catfish. The purpose of this study was to quantify habitat and diet overlap of these two species. Methods We used acoustic telemetry and gastric lavage to quantify resource use and overlap of Blue Catfish and Channel Catfish in two northeastern Kansas reservoirs during 2023 and 2024. We used generalized linear models and multivariate ordination techniques to analyze the data. Results Our analysis revealed that Blue Catfish lived farther from shore and occupied deeper water (x¯ = 6.84 ± 4.35 m) than Channel Catfish (x¯ = 5.09 ± 3.27 m). Although both species exhibited similar movement patterns and diverse diets, we found that Channel Catfish fed more frequently on crayfish and terrestrial macroinvertebrates than Blue Catfish. Variables relating to season and reservoir strongly influenced the diets of both species. Conclusions Our results demonstrate that co-occurring populations of Blue Catfish and Channel Catfish use a wide variety of habitat and dietary resources, yet they also have distinct niches that might mitigate the intensity of competitive interactions. Continued monitoring of these populations is crucial for evaluating population trends and competitive interactions. This will allow for informed management plans to prevent negative effects on both species’ populations and abundance of other species.