Demographics and Interstate Management Implications for Flathead Catfish in the Lower Wabash River, Illinois and Indiana

Abstract

Flathead Catfish Pylodictis olivaris in the lower Wabash River, Illinois and Indiana, are currently exploited by anglers and commercial fishers under the same fishing regulation; however, the regulations differed between the states prior to 2015. We assessed demographics of Flathead Catfish in this interstate river to gain baseline information to create models to test for sustainable exploitation rates under the new regulation and several hypothetical scenarios. During 2010–2012, we sampled 951 Flathead Catfish (length = 343 ± 5.6 mm [mean ± SE], weight = 914.5 ± 55.6 g, age = 3.5 ± 0.07 years) using pulsed-DC electrofishing, AC electrofishing, commercial harvest, and hoop nets. Mean relative weight of Flathead Catfish was greater than 100%, and proportional size distribution indices (electrofishing = 35, hoop netting = 54) suggested a quality fishery. Total annual mortality (electrofishing = 0.48, hoop netting = 0.54) was similar to estimates in other Midwestern rivers. Yield-per-recruit models predicted that growth overfishing may occur over time under the current regulation; however, demographic metrics relate to recreational and commercial creel assessments. Our results suggest that the current minimum length limit could be raised to increase yield and reduce exploitation. Our findings also demonstrate several useful field and modeling techniques to assess catfish (family Ictaluridae) populations in environments that are difficult to sample and that lack fishery-independent information.

Received January 11, 2017; accepted August 31, 2017 Published online October 20, 2017

ACKNOWLEDGMENTS

This research was funded by the U.S. Fish and Wildlife Service, Federal Aid in Sportfish Restoration Program, F-101-R, in conjunction with the Illinois Department of Natural Resources and the Long-term Illinois, Mississippi, Ohio, and Wabash River Fish Population Monitoring Program awarded to Andrew Casper, John Epifanio, and Greg Sass. This study would not have been possible without the very generous help of the graduate and undergraduate students of the fisheries and aquatic research team at Eastern Illinois University. Specifically, we want to recognize John West, Jason Stuck, Sarah Huck, Megan Krick, Anthony Porecca, Manisha Pant, Vaskar Nepal, Todd Bollinger, Avril Harder, and Matt Hladelik for lab and field assistance.