Assessment of Catfish Stocking in Public Fishing Lakes in Alabama

From 1974 to 1993, nearly 2 million catfish Ictalurus spp. (primarily channel catfish I. punctatus), weighing about 500,000 lb, were stocked into 18 public fishing lakes throughout Alabama where natural recruitment to the fishery was nil. Using stocking and angler catch and effort records for these lakes, we examined factors related to catfish harvest, identified the most and least successful catfish fisheries, and attempted to determine optimal stocking size and cost-benefit ratio. About 1 million catfish, weighing 1.5 million pounds, were harvested; this conferred a minimum exploitation rate of 52% and a net return of 300% by weight. Harvest rates were highly variable and ranged from 0.4 to 311 fish/acre and from 1 to 320 lb/acre. In multiple regressions for all lakes and years pooled, biomass and number of catfish stocked and angler effort explained the most variation in catfish harvest rates. These models explained 68% of the variation in number of catfish harvested and 56%o of the weight harvested. Residuals from these models were useful in identifying successful and unsuccessful catfish fisheries. Stocking channel catfish larger than 10 in or 0.28 lb was associated with greater angler harvest. Cost-benefit ratios for value of harvested catfish to anglers was 1:1.45 for 6-in catfish and 1:2.13 for 12-in catfish. Numerically, harvest increased linearly with stocking density, which suggested that an optimal stocking density did not exist for the range of stocking densities examined. Our analytical procedure provides a tool for managers to assess factors related to the quality of catfish fisheries.