Submitted to: American Fisheries Society Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 7/15/2008
Publication Date: 8/15/2008
Citation: Weirich, C.R., Wills, P.S., Baptiste, R.M., Riche, M.A. 2008. Production of juvenile and sub-adult cobia in recirculating aquaculture systems [abstract]. 138th American Fisheries Society Annual Meeting: Book of Abstracts. p.20-22.
Technical Abstract: Cobia Rachycentron canadum is a large migratory pelagic finfish species that is distributed worldwide in tropical, subtropical, and warm temperate seas except the Mediterranean and the central and eastern Pacific. Despite its large size, commonly exceeding 23 kg at maturity, and excellent food quality, annual US commercial cobia landings over the past ten years have not exceeded 200 mt, with the majority of fish harvested through recreational means. When available, cobia fillets are sold in Gulf and South Atlantic seafood outlets for approximately US $8.00/kg, indicating excellent consumer appeal. In addition, cobia exhibit exceptional growth rates, attaining a weight of 4-6 kg in one year. Primarily because of these two factors, coupled with the success of initial efforts to spawn and culture this species in Taiwan, interest in cobia aquaculture has increased greatly in the US in recent years. Although the principal culture system employed for the production of cobia currently is offshore net-pen rearing, establishment of land-based recirculating culture technologies for cobia could mitigate some concerns associated with permitting, effluent discharge regulations, and restrictions on the use of coastal waters. To investigate this topic experiments were initiated in 2007 using commercial scale recirculating aquaculture systems (RAS). To date two rearing trials have been conducted. In the first rearing trial, the effect of feeding different commercial diets on production of juvenile cobia (initial weight = 29 g) was evaluated. After a rearing period of 56 d, results indicated that feed type significantly affected production with fish fed the superior diet exhibiting a mean weight of 311 g, a specific growth rate of 4.2 %/d, and a feed conversion ratio of 1.17. Across-treatment survival was 98.5 %. In the second rearing trial juvenile cobia (initial weight = 322 g) were reared at different densities for 118 d. Although at the time of writing all data had not been entered and analyzed, across-treatment mean final weight and survival was 2.14 kg (range = 0.80-4.17 kg) and 99.4 %, respectively. Results of our work thus far clearly indicate that RAS culture of cobia has excellent potential for the provision of food animals and the same techniques could potentially be employed to produce fish for stock enhancement purposes.