Location: Warmwater Aquaculture Research UnitTitle: Growth and feed conversion of pond-raised hybrid catfish harvested at different sizes Author
Submitted to: North American Journal of Aquaculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/30/2014
Publication Date: 6/13/2014
Citation: Li, M.H., Robinson, E.H., Bosworth, B.G., Torrans, E.L. 2014. Growth and feed conversion of pond-raised hybrid catfish harvested at different sizes. North American Journal of Aquaculture. 76:261-264. Interpretive Summary: Hybrid catfish have been cultured in southern United States for over 50 years. They generally grow faster, are more resistant to certain diseases, and have better survival than channel catfish. Improvements in hybrid fingerling production technologies have allowed recent dramatic increases in commercial hybrid catfish production. With the downsizing of the overall catfish industry in the United States and the increase in hybrid catfish production, hybrid catfish is currently estimated to account for about 30-40% of the total catfish production for food fish. Recently there has been increasing interest in the “premium cut” large fillets by certain retail markets and high-end food services. The fillets are “deep skinned” to remove outer layer of tissue and fat under the skin, and marketed as “Delacata™ Style Catfish” (The Catfish Institute, Jackson, Mississippi). The preferred size of fillet is approximately 200-250 g, which requires large fish in the range of 1.3–1.7 kg. Because hybrid catfish grow faster than channel catfish, they could be a good choice for this specialty market. Therefore, the present study was initiated to compare the growth, feed consumption, and FCR for pond-raised hybrid catfish harvested in either the first or second growing season at different sizes. Results suggest under normal economic conditions it is generally more cost effective to harvest food-size hybrid catfish after one growing season because of increased FCR the following year, assuming feed and fish prices are unchanged. Further, if fish are raised for large fillet markets, hybrid catfish appear to be a good choice because they continue to grow rapidly in the second season easily obtaining a size suitable for Delacata™ Style Catfish or other large fillet markets.
Technical Abstract: A study was conducted to examine growth and feed conversion ratio (FCR) of pond-raised hybrid catfish (channel catfish Ictalurus punctatus × blue catfish I. furcatus) harvested at different sizes. Fingerling hybrid catfish (mean initial weight ± SD = 62 ± 2.0 g/fish) were stocked into 25 earthen ponds (0.04 ha) at a density of 14,826 'sh/ha. Fish were fed daily to apparent satiation with a commercial 28% protein feed. When fish reached a predetermined weight (0.454, 0.680, 0.907, 1.361, or 1.814 kg/fish), they were harvested. Fish grown to 0.46 kg and 0.70 kg during the first season had FCRs of 1.61 and 1.59, respectively. Fish carried-over for second season were harvested at mean weights of 0.85, 1.43, and 2.01 kg/fish, respectively. These fish had FCRs of 1.97, 2.10, and 1.93, respectively, significantly higher than fish harvested in first season. Results suggest it is generally more cost effective to harvest food-size hybrid catfish after one season because of increased FCR the following year. However, if fish are raised for large fillet markets, hybrid catfish appear to be a good choice because they continue to grow and utilize feed relatively well in second season.