Evaluation of Population Structure, Age, Growth, and Mortality of Blue Catfish and Flathead Catfish within the Robert C. Byrd Pool of the Ohio and Kanawha Rivers

Abstract

The Ohio River is continuing to recover from a long history of anthropogenic impacts. Blue Catfish were considered locally extirpated from the West Virginia sections and have been reintroduced through fingerling stockings beginning in 2002. Flathead Catfish are naturally sustaining in the pool and combined with Blue Catfish provide two popular recreational fisheries. The Blue Catfish and Flathead Catfish studies shared similar objectives: (1) evaluating size structure, (2) estimating growth rates, and (3) estimating annual mortality. From 2017 to 2020, we collected catfish annually through low frequency electrofishing and trotline surveys at 10 fixed locations. Electrofishing catch rates for Blue Catfish were poor, suggesting low densities. The presence of numerous sub-stock sized Blue Catfish supported natural reproduction. Electrofishing CPUE’s for Flathead Catfish suggested a stable population with densities decreasing through the larger size classes. Trotline CPUE’s demonstrated the trophy potential and gear bias for both species. Age analysis results supported variable recruitment in Blue Catfish. Back calculated hatch years of aged Blue Catfish pre- and post-dated stocking, providing evidence of a remnant population and further supporting natural reproduction. Blue Catfish growth was lower than expected for a newly reintroduced population. Flathead Catfish were long lived and slow growing with a maximum observed age of 34. Mortality estimates were low for both species suggesting low fishing mortality. The information provided from this study on population parameters could be useful for informing management decisions of Blue Catfish and Flathead Catfish fisheries in the Robert C. Byrd Pool.