Effects of Stocking Rate, Stocking Size, and Angler Catch Inequality on Exploitation of Stocked Channel Catfish in Small Missouri Impoundments

Put–grow–take fisheries for channel catfish Ictalurus punctatus provide popular sport fisheries in many small impoundments and lakes throughout the United States. These fisheries are costly to maintain because the fish that are stocked are usually large fingerlings (>175 mm total length). Given the substantial fiscal and human resources required, it is important that these stockings contribute to the fishery. We estimated the exploitation of stocked channel catfish by tagging fish in 14 small impoundments to determine their use. Secondly, we determined whether the stocking rate, stocking size, and angler catch inequality (proportion of tags returned) affected exploitation. Annual exploitation varied more than 10-fold among the impoundments, ranging from 0 to 0.65 for the year after the fall stockings and usually declining thereafter. Cumulative exploitation in the 3 years after stocking ranged from 0 to 0.69, indicating that there is wide variation in the use of the stocked fish. Exploitation was unrelated to the stocking rate but was affected by stocking size, larger fish being more vulnerable than smaller fish to catch and harvest. In several impoundments, one to three anglers accounted for one-third or more of all returned tags, showing that just a few anglers can markedly affect exploitation. These results suggest that exploitation can be dynamic, changing with stocking size and angling clientele. Despite this inherent variability, we found substantial differences in exploitation among lakes. Managers should focus on impoundments where channel catfish are heavily exploited, possibly by stocking more fish or implementing protective harvest restrictions. For lightly exploited lakes, reducing stockings may be necessary to improve the growth and size structure of channel catfish.