Growth, mortality, harvest, and cost-effectiveness of stocked channel catfish in a small impoundment

We compared mortality and harvest of 200-mm and 250-mm channel catfish Ictalurus punctatus stocked in equal numbers for 4 years in an impoundment containing populations of largemouth bass Micropterus salmoides and bluegill Lepomis macrochirus. Based on a 5-year creel census, 52–92% of stocked fish were harvested. We found no difference between the stocked length-groups in terms of mean number caught (N = 365 for 200-mm and 392 for 250-mm fish), mean number harvested (66% for 200-mm and 83% for 250-mm fish), or mean total weight harvested (116 kg for 200-mm and 164 kg for 250-mm fish). Stocking mortality, largemouth bass predation, hooking mortality, and spillway escapement were low for both length-groups in all years. Harvest was the most important source of mortality in these populations. Growth rates were high, and within years did not differ between length-groups. High exploitation, fast growth, and low hooking mortality suggest length limits may be useful for deferring harvest of channel catfish in small impoundments until they reach a larger size. Based on analysis of cost effectiveness (catch and harvest/cost of stocking), the return on investment was similar for fish from both length-groups. Consequently, we do not recommend stocking channel catfish larger than 200 mm for most putgrow-and-take fisheries.