Location: Warmwater Aquaculture Research UnitTitle: Impact of minimum daily dissolved oxygen concentration on production performance of hybrid female channel catfish x male blue catfish
Submitted to: North American Journal of Aquaculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/1/2015
Publication Date: 9/17/2015
Citation: Torrans, E.L., Ott, B.D., Bosworth, B.G. 2015. Impact of minimum daily dissolved oxygen concentration on production performance of hybrid female channel catfish x male blue catfish. North American Journal of Aquaculture. 77(4):485-490.
Interpretive Summary: Hybrid catfish (a cross of a female channel catfish and a male blue catfish) are becoming increasingly popular with commercial catfish farmers in the USA. This year approximately half of the domestic catfish production will be hybrids. As aeration is an important, and expensive, part of the pond production systems, knowing how much to aerate is very important. These studies were conducted to determine how much aeration is necessary, i.e., how various dissolved oxygen concentrations affect hybrid catfish feed consumption, growth and production. The good news for the industry is that hybrid catfish eat more feed and grow faster than do channel catfish when maintained at the same dissolved oxygen concentration.
Technical Abstract: Hybrid Catfish (female Channel Catfish Ictalurus punctatus X male Blue Catfish I. furcatus) were reared during two years as single-batch crops under two different dissolved oxygen (DO) regimes each year; a high-DO (control) treatment in which the minimum daily DO was maintained above 3.8 ppm during the growing season (June through September), and a low-DO (test) treatment in which the minimum DO was maintained at 1.6 or 1.3 ppm in the two years. Fish were fed to apparent satiation daily with a 32% protein commercial feed, and clean harvested each year. Dissolved oxygen concentration significantly impacted gross and net production, final fish weight and mean fish weight gain due to reduced feed intake when fish were maintained at reduced DO concentrations both years. Feed intake was reduced in the low DO treatment by 26.6% in year 1 (1.6 ppm minimum DO), and 29.2% in year 2 (1.3 ppm minimum DO); FCRs averaged 1.83 overall and were not affected by minimum DO. Fish in the high-DO treatments gained an average of 44% more weight (an average of 1.50 lbs/fish gain in the high-DO treatments, compared to 1.04 lbs/fish gain in the low-DO treatments). Initial weight at stocking also had a significant impact on weight gain. Fish stocked at 0.16 lbs average weight (year 2) gained 37% more weight than fish stocked at 0.11 lbs average weight (year 1), even though the stocking rate of the larger fish was 50% higher. Hybrid catfish responded better than (less reduction in feed intake at reduced DO) reported values for Channel Catfish and similarly to reported values for Blue Catfish.