Location: Warmwater Aquaculture Research UnitTitle: Growth and Feed Efficiency of Channel × Blue Catfish Hybrids Stocked at Various Densities and Fed Once or Twice Daily in Ponds Author
Submitted to: North American Journal of Aquaculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/29/2009
Publication Date: 4/1/2010
Publication URL: http://handle.nal.usda.gov/10113/55482
Citation: Li, M.H., Minchew, C.D., Robinson, E.H., Tucker, C.E., Bosworth, B.G., Heikes, D.T. 2010. Growth and Feed Efficiency of Channel × Blue Catfish Hybrids Stocked at Various Densities and Fed Once or Twice Daily in Ponds. North American Journal of Aquaculture. 72:150-157. Interpretive Summary: There is increasing interest in raising channel x blue catfish hybrids because they are more resistant to certain diseases affecting channel catfish and thus have higher survival In addition, catfish hybrids grow and convert feed more efficiently than do either parent and have a higher carcass yield than do channel catfish. Economic analysis indicates that hybrid catfish fingerling and food fish production are generally more profitable than channel catfish at moderate feed prices, even though the cost of fry and fingerlings are higher and more capital is required for the hybrids. We conducted two experiments to evaluate the effects of stocking density and feeding frequency on the growth, net yield, and feed conversion of hybrid catfish. Results from both experiments showed that feeding channel x blue catfish hybrids twice daily to satiation did not improve weight gain and net yield, but increased FCR. In experiment 2, a stocking density of 18,532 fish/ha resulted in higher weight gain per fish, but a lower net yield compared with a stocking density of 24,710 fish/ha. It appears that it is efficient to stock hybrids at a density of about 12,355 fish/ha, feed once daily for a growing season, and ‘‘clean’’ harvest at the end of the growing season. However, a multiple-batch system may also be used to grow hybrids at densities of 18,532–24,710 fish/ha by using a fish grader to remove market-size fish.
Technical Abstract: Two experiments were conducted to evaluate the effects of stocking density and feeding frequency on the growth, net yield, and feed conversion of hybrid catfish (female channel catfish Ictalurus punctatus x male blue catfish I. furcatus). In experiment 1, hybrid catfish fingerlings with a mean initial weight of 65 g were stocked into ten 0.4-ha earthen ponds at a density of 12,355 fish/ha. In experiment 2, hybrid catfish fingerlings with the same mean initial weight as in experiment 1 were stocked into twenty 0.4-ha earthen ponds at densities of 18,532 and 24,710 fish/ha, respectively. Fish were fed once or twice daily to apparent satiation. In experiment 1, all fish were harvested in early September. In experiment 2, market-size fish (target size: 0.794 kg/fish) were selectively harvested in late September by means of an in-pond mechanical fish grader with the bar spacing set to 5.4 cm. All remaining fish were harvested in mid-June the next year. In both experiments, fish fed twice daily were given more feed, but there were no significant differences in weight gain per fish and net yield between fish fed once daily and those fed twice daily. Fish fed twice daily had a significantly higher feed conversion ratio. In experiment 2, a stocking density of 18,532 fish/ha resulted in higher weight gain and lower net yield than a stocking density of 24,710 fish/ha. Based on the results from this study, it appears to be efficient to stock hybrids at a density of 12,355 fish/ha, feed them once daily over a growing season, and ‘‘clean’’ harvest them at the end of the season. However, a multiple-batch system may also be used to grow hybrids at densities of 18,532–24,710 fish/ha by means of a catfish grading system to remove market-size fish.