Blue Catfish Gut Contents: An Assessment of Feeding Adaptation in Response to Asian Carp Invasion in the Mississippi River Basin

Blue catfish (Ictalurus furcatus) have been extensively studied in their native environment. However, their diet preference and feeding behavior has not been evaluated in the presence of non-native Asian carp (Hypopthalmichthys sp.). We examined the gut contents of adult blue catfish (567 mm – 1020 mm, n= 60) from an impounded backwater in pool 26 of the Mississippi River near Alton, IL. Blue catfish diets were collected by gastric lavage and manual prompting. The gut contents were immediately placed on ice and then frozen upon return to the lab. Individual diets were separated by taxa, visually counted and enumerated based on hard structures, wet weights and dry weights obtained and unidentified fish species were confirmed with genetic analysis.   Adult Asian carp were identified as the primary fish species with the highest frequency of occurrence found within blue catfish diets and constituted the greatest percentage of the diet by weight   Average age of silver carp consumed was nearly 4 years old determined as determined by spines, postcleithra, and vertebrate retrieved from the diets.  Diet adaptation of a top-tier predator to a highly invasive species complex offers a unique look at biological control and management within the Mississippi River Basin.