Flathead Catfish Gear Assessment and Demographics in the Wabash River

Flathead catfish, Pylodictus olivarious, are a popular game fish in the Midwestern United States. In the lower 322 km of the Wabash River, flathead catfish are commercially harvested by Illinois and Indiana fishers. Current management regulations are different between the two states. Illinois and Indiana have minimum size limits of 381 and 254 mm respectively. Indiana has proposed changing their minimum size limit to 381 mm and allowing only one fish over 889 mm to be harvested. Our project has been assessing the current status of flathead catfish in the Wabash River to determine a standardized sampling protocol and potential management options for the state of Illinois. We sampled flathead catfish using AC and DC electrofishing during the summer of 2010-2012. We also set hoopnets and trotlines in 2011, but only added hoopnetting in 2012. 952 flathead catfish that averaged 343 mm and 914.5 g were collected during our efforts. The fish had an average age of 3.5 years (range 0-9 years). Relative weight was above 90 for most of the gears in each year. DC electrofishing had the highest catch per unit effort (28.2 fish/hour) and hoopnetting caught larger fish (HP PSD=88, DC PSD=40); therefore a multi-gear approach is the best approach for sampling. Mortality (Z=0.51) seemed high; however previous estimates were around the same. The yield per recruit model implies that at current harvest limits the fishing is not sustainable. There is some information that is lacking about the population that will determine if there is a need for a regulation change. Overall, this population is doing well and is a sustainable resource unless some drastic changes occur within the fishery.