Recruitment and Population Dynamics of Blue Catfish in the Ohio River

Blue Catfish is an important recreational species in the Ohio River and are commercially harvested. However, a lack of data on demographics and recruitment dynamics limits understanding of the most appropriate spatial scale for management and predicting responses to changes in harvest regulations. The objectives of this study were to estimate growth and mortality rates, identify principal natal environments, and estimate emigration and immigration rates of blue catfish in the lower Ohio River. Sampling for blue catfish was conducted June-October 2012 - 2014 using multiple gears. Lapilli otoliths were sectioned, aged and analyzed for δ¹⁸O, Sr:Ca and Ba:Ca. Water samples from the Ohio River and its tributaries were collected from 2010-2014. These water samples were used to describe river and tributary-specific δ¹⁸O, Sr:Ca and Ba:Ca signatures. Results indicate differing patterns of recruitment in the Ohio River from the nearby Mississippi River and similarity of principal recruitment sources between blue catfish and the other two commercially exploited catfish species in the Ohio River. Ohio River blue catfish growth rates did not differ between river- and tributary-origin fish. This study will be valuable for protecting important juvenile nursery habitats and assessing interactions among catfish stocks in the Ohio River and its tributaries.