Seasonal variation in the feeding ecology of Channel Catfish Ictalurus punctatus and Blue Catfish Ictalurus furcatus in Ohio reservoirs
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Date
2023-05
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The Ohio State University
Abstract
The introduction of novel species into aquatic ecosystems can threaten native taxa through numerous mechanisms, such as interspecific competition. Generalist species are particularly dangerous due to their breadth of resource-use, especially if their ecological nice overlaps with other resident species. Toward understanding the impact of the Blue Catfish (Ictalurus punctatus), a stocked, non-native generalist consumer, on Channel Catfish (Ictalurus furcatus), an ecologically similar congener, we analyzed the stomach contents of Blue Catfish (n = 148) and Channel Catfish (n = 296) collected during multiple seasons in Hoover Reservoir (where Blue Catfish is stocked) and Alum Creek Lake (where Blue Catfish is absent). Stomach content analyses revealed that Channel Catfish diets are more diverse than Blue Catfish in both sympatry and allopatry. Channel Catfish diets consisted of aquatic and terrestrial invertebrates and plant material in Channel Catfish, with prey-fish such as Gizzard Shad (Dorosoma cepedianum) being also found in larger individuals. By contrast, chironomids and Gizzard Shad dominated the diets of Blue Catfish. Channel Catfish total consumption and mass per unit of length also were lower in sympatry (Hoover) than in allopatry (Alum Creek), suggesting the potential for interspecific competition for prey resources. While more investigation is needed to determine if interspecific competition is truly occurring, our findings provide valuable information for managers and ecologists interested in understanding the potential consequences of introduced non-native generalist consumers on native species.
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Keywords
Foraging ecology, Interspecific competition, Food web interactions, Introduced species, Fish stocking, Managed reservoirs