Effects of nonindigenous ictalurids and recreational electrofishing on the ictalurid community of the Cape Fear River drainage, North Carolina

Flathead catfish Pylodictis olivaris and blue catfish Ictalurus furcatus were transplanted into the lower Cape Fear River in 1966 and a novel recreational electroshocking fishery was established in 1985. We evaluated changes in ictalurid community structure between 1990 and 1992 and 1996-1997 and assessed the findings by comparison to previous surveys. No native catfish species were collected in 1996 or 1997. The catch per unit effort (CPUE) of blue catfish was significantly higher in areas open to electrofishing than in areas closed to electrofishing, the CPUE of flathead catfish was not significantly different. Blue catfish fed almost exclusively on introduced Asiatic clams Corbicula fluminea. We attribute the proliferation of the blue catfish to their opportunistic feeding on introduced Asiatic clams and their lower susceptibility to diminished water quality and hand-cranked electroshockers (as compared to flathead catfish). introduced flathead catfish and blue catfish have apparently eliminated native ictalurids from the main channel areas of the Cape Fear River system.