ARS | Publication request: Production characteristics of juvenile cobia fed three different commercial diets in recirculating aquaculture systems

Submitted to: Book of Abstracts Aquaculture America
Publication Type: Abstract Only
Publication Acceptance Date: November 6, 2007
Publication Date: February 9, 2008
Citation: Weirich, C.R., Willis, P.S., Baotuste, R.M., Woodward, P.N., Cavalin, F.G., Benetti, D.D., Riche, M.A. 2008. Production characteristics of juvenile cobia fed three different commercial diets in recirculating aquaculture systems [abstract]. Book of Abstracts Aquaculture America. p. 429.

Technical Abstract: Interest regarding cobia Rachycentron canadum aquaculture in the US has increased greatly in the last decade due to their excellent consumer appeal, extremely rapid growth rates, and the observed success of rearing this species in Taiwan. However, limited information exists with respect to nutritional requirements of juvenile cobia and diet development for this species. While studies have been conducted on topics such as determination of optimal protein and lipid levels, apparent digestibility of various feed ingredients, and replacement of fish meal, no studies have been conducted to date to compare production of juvenile cobia fed commercial marine finfish diets currently available in the US. To address this topic production characteristics of juvenile cobia fed different commercial diets and reared to stocker size (250-300 g) in commercial scale recirculating aquaculture systems (RAS) were compared. Juvenile cobia (mean wt. = 29 g) were stocked into four RAS, each containing three 8 m3 culture tanks, at an initial density of 1.2 kg/m3. Fish in each system were fed one of three commercial Zeigler diets: Marine Grower (MG; 50% CP, 15% CL), Finfish Gold (GOLD; 42% CP, 16% CL), or Hybrid Striped Bass (HSB; 44% CP, 12% CL). Fish were fed twice daily at a rate of 5% body weight/day. Salinity and water temperature were maintained at 25-30 g/L and 28-30 C, respectively, at a photoperiod of 12L:12D. At two week intervals production characteristics including mean weight, specific growth rate (SGR, %/day), feed conversion ratio (FCR), and survival were estimated by sampling 10% of the population in each tank. At the conclusion of the experiment production characteristics were determined by total harvest of each tank. Results to date reveal that juvenile cobia fed the MG diet exhibit superior growth and FCR when compared to fish fed GOLD and HSB diets. High survival of fish fed each diet to date indicates that RAS have excellent potential as a culture option for the production of stocker size cobia. In addition to a complete analysis and discussion of production characteristics, data on whole body composition and hepatosomatic index will be presented.