Channel Catfish Farming: A Production Guide
How channel catfish (Ictalurus punctatus) is farmed: biology, levee-pond culture, spawning and fingerling supply, feeding and growth, off-flavor management, harvest and main diseases.
Overview
Channel catfish (Ictalurus punctatus) is native to North America and is the backbone of the United States aquaculture industry, making up the large majority of farm-raised catfish there. It is a hardy, omnivorous member of the family Ictaluridae, well suited to warm-water pond culture, and is farmed mainly in the southern United States. Its tolerance of handling, formulated feed and pond conditions has made it a model food-fish species.
Biology and requirements
Channel catfish are omnivores that eat a wide range of plant and animal material. They are warm-water fish: extension sources give an optimum growth temperature range of roughly 26 to 30 °C (about 75 to 85 °F), with survival from near freezing to very warm water, although growth and feeding slow markedly in cold conditions. Like all pond fish they depend on adequate dissolved oxygen, which is managed with aeration at the high stocking rates used in production.
Pond culture
Most channel catfish are grown in earthen levee ponds, stocked at high density and supported by mechanical aeration and daily feeding. Production can be run as a single batch or, commonly, with multiple-batch and partial-harvest systems so that market-size fish are removed while smaller fish grow on. FAO records pond production figures on the order of a couple of thousand kilograms per hectare over a growing season at stocking rates of several thousand fingerlings per hectare with supplemental pelleted feed.
Spawning and fingerling production
Channel catfish are cavity nesters: in the wild and in ponds the male guards the eggs in a sheltered nest. Hatcheries exploit this by providing spawning containers (such as cans or pipes) in brood ponds or pens, then collecting the egg masses for hatchery incubation, with hypophysation also used. Fecundity is roughly several thousand eggs per kilogram of female body weight. Hatched fry are reared in nursery ponds to fingerling size before stocking into grow-out ponds.
Feeding and growth
Production catfish are fed a floating pelleted diet, typically around 28 to 32 percent protein, fed daily so that feeding can be observed. Floating pellets let the farmer see how much the fish eat and adjust the ration, which helps control feed cost and water quality. Fish are grown to a market size of about 1 to 2 pounds (roughly 0.5 to 0.9 kg), reached over one or more growing seasons depending on temperature and management.
Off-flavor management
Pond catfish can develop a muddy or musty off-flavor from the compounds geosmin and 2-methylisoborneol (MIB) produced by certain cyanobacteria and absorbed into the fish's fat. Fish are flavor-checked before harvest and held in clean water to depurate if needed, which can delay harvest by days or weeks. Off-flavor is a quality, not a safety, issue but it strongly affects marketability.
Harvest and main diseases
Catfish are usually harvested by seining the pond, often as a partial harvest of market-size fish, sometimes aided by fish pumps. The most important diseases include enteric septicemia of catfish (ESC), caused by the bacterium Edwardsiella ictaluri, columnaris disease (Flavobacterium columnare), and proliferative gill disease. Good water quality, controlled stocking and biosecurity are the main defenses, alongside vaccination and treatment where available.