Submitted to: Aquaculture
Publication Type: Abstract Only
Publication Acceptance Date: 12/13/2005
Publication Date: 2/13/2006
Citation: Li, M.H., Robinson, E., Mischke, C.C., Torrans, E.L., Bosworth, B.G. 2006. Effects of Organic Fertilization and Organic Diets on Production of Channel Catfish, Ictalurus punctatus, in Earthen Ponds. [Abstract]. In: Book of Abstracts. Aquaculture America, February 13-16, 2006, Las Vegas, Nevada. p. 167. Interpretive Summary:
Technical Abstract: In recent years, there has been growing public interest in organically grown foods. Organically produced foods once found only in specialty food stores are now common in regular grocery stores. However, currently there are no organic aquaculture standards in the U.S. Once organic aquaculture standards have been developed for US producers, research in various areas will be needed to assist potential producers. Channel catfish is the number one fish species cultured in the United States. It possesses several traits, such as rapid growth, easy spawning, tolerance to wide ranges of temperature and water quality, and lower protein requirements, which make it a suitable candidate for organic production. Currently, there is no information on the efficiency of organic fertilization in catfish nursery ponds. Also, questions remain on effects of organic diets on growth and body composition of food fish since organic oilseeds and grains are grown and processed differently from the conventional crops and therefore their nutrient composition may be different. A study was conducted to evaluate effects of organic fertilization and organic diets on production of channel catfish Ictalurus punctatus. Since formal organic aquaculture standards do not yet exist for the U.S., a presumptive organic program based on U.S. livestock organic standards was developed for this study. During fingerling production, four 0.4-ha earthen ponds were fertilized with a combination of inorganic fertilizers and regular cottonseed meal (control) and four with organically produced cottonseed meal only (organic). Swim-up fry were stocked into each pond at a rate of 247,000 fish/ha and fed a control or organic diet daily to apparent satiation for a growing season. During food fish production, overwintered control and organic fingerlings from fingerling production were each stocked into five 0.04-ha ponds at a rate of 14,800 fish/ha and fed a control or organic diet daily to apparent satiation for a growing season. During fingerling production, ponds fertilized with a combination of inorganic fertilizers and cottonseed meal had higher total N and P and preferred zooplankton densities than ponds fertilized only with organically produced and processed cottonseed meal. Gross fingerling production in organic ponds was lower than that in the control. During food fish production, there were no differences in production characteristics and carcass yield between conventionally and organically grown fish. However, organic fish had lower fillet yield and higher body fat than control fish. The slightly higher body fat observed in organic fish likely resulted from the slightly higher fat content in the organic diet. Results from this study indicate that channel catfish can be grown from swim-up fry to food size organically, though gross production during the first season may be lower in organic ponds in part because of the lower abundance of preferred zooplankton in ponds fertilized only with organic cottonseed meal. Further studies are needed to evaluate other natural inorganic and organic fertilizers in catfish nursery ponds for organic aquaculture.