Characteristics of four Blue Catfish fisheries with implications for harvest management

Abstract Objective Blue Catfish Ictalurus furcatus populations introduced into Kansas reservoirs in the past few decades have supported fisheries during the 21st century that have rapidly gained popularity among anglers. The increased importance of these fisheries has prompted questions about the status of populations, resilience to overfishing, and appropriate harvest management strategies. The primary objectives of this study were to quantify the dynamics of four Blue Catfish populations in Kansas impoundments, identify susceptibility to angler catch and harvest, and evaluate modeled population responses to harvest regulation. Methods We coupled capture–recapture efforts and a randomized sample design using low-frequency electrofishing to estimate population characteristics of the four Blue Catfish populations. We also estimated age and growth parameters from each population to characterize dynamic rate functions. Angler tag return data were summarized over a period of 1 year from each fishery to evaluate Blue Catfish susceptibility to angler catch and harvest. Finally, we consolidated these data into harvest regulation models to estimate the population response under varied harvest regimes. Result Estimated densities of stock-length (≥300 mm total length) Blue Catfish varied from 2.79 to 20.14 individuals/ha. Growth was variable, with individuals expected to reach quality length (≥510 mm total length) as early as age 4 and as late as age 9. The largest fish in each population were more vulnerable to angler capture, although harvest was low for all sizes of fish. Harvest regulation models indicated that populations were resilient to increased exploitation under all scenarios, with a limited risk of growth overfishing or recruitment overfishing. Conclusion Blue Catfish populations in Kansas reservoirs exhibit different dynamics but demonstrate resilience to overfishing. The largest individuals in populations are much more vulnerable to angler catch than smaller fish, but the risk of overharvest appears mitigated by angler self-regulation.