Recruitment of Channel Catfish stocked as fingerlings and yearlings in Ohio reservoirs

Abstract Objective Stocking of yearling Channel Catfish Ictalurus punctatus to mitigate perceived predation risk from Largemouth Bass Micropterus nigricans has long been the management convention despite greater costs compared to stocking younger life stages (e.g., fingerlings). To test this convention, we quantified the effects of stocked life stage (fingerling vs. yearling), Largemouth Bass density (low vs. high), and their interaction on the percentage of a Channel Catfish cohort that recruited to the adult population in 12 Ohio reservoirs. Methods Marked (magnetized wire tags) cohorts of fingerling and yearling Channel Catfish were concurrently stocked into reservoirs with low-density (seven reservoirs; CPUE < 100 fish/h) and high-density (five reservoirs; CPUE > 150 fish/h) Largemouth Bass populations. We sampled Channel Catfish in each reservoir with baited tandem hoop nets 7–8 years after stocking and estimated recruitment. We used a linear mixed model with reservoir as a random effect to test whether cohort recruitment differed based on the life stage stocked, Largemouth Bass density, and their interaction. Results Channel Catfish stocked as fingerlings and yearlings successfully recruited to adult populations. The mean percentage of Channel Catfish recruiting to the adult population was 2.4% (SE = 2.4) in cohorts stocked as fingerlings and 10.6% (SE = 9.8) in cohorts stocked as yearlings. Largemouth Bass density did not significantly affect recruitment, whereas stocking life stage and the Largemouth Bass density × stocking life stage interaction did have significant effects. The highest recruitment occurred in cohorts stocked as yearlings in reservoirs with high densities of Largemouth Bass. Conclusions Although they recruit to the adult population at a lower rate than yearling-stocked Channel Catfish, fingerling-stocked Channel Catfish can produce detectable year-classes in reservoirs with low or high densities of Largemouth Bass. Further research should investigate stocking rates so that managers can weigh the trade-off between lower recruitment of fingerlings and higher production costs for—but greater recruitment of—yearlings.