Submitted to: Global Aquaculture Advocate
Publication Type: Trade journal
Publication Acceptance Date: 2/15/2008
Publication Date: 3/1/2008
Citation: Weirich, C.R., Will, P.S., Baptiste, R.M., Woodward, P.N., Riche, M.A. 2008. Pompano reared to market size in RAS: Low salinity culture successful. Global Aquaculture Advocate. 10(2):58-60. Interpretive Summary:
Technical Abstract: Florida pompano, Trachinotus carolinus, are found in coastal waters of the Atlantic Ocean from Massachusetts, USA, to Brazil and throughout the Gulf of Mexico. Due to pompano’s superior market value, interest in its culture developed in the US during the 1960s and 1970s. Research conducted during this time period focused largely on developing production methods using ponds, in-pond cages, and flow through tanks. Common results for these studies included poor growth and feed conversion of fish greater than 200 g, usually coupled with poor survival, resulting in the inability to produce market-size fish of greater than 450 g. However, in a study conducted at Louisiana State University by the lead author using small-scale recirculating aquaculture systems (RAS)maintained at a salinity of 23-28 ppt, it was demonstrated that juvenile pompano can be reared at relatively low densities from an initial weight of 17 g to over 450 g in four to five months and 700 g in eight to nine months, with 95%survival. To build upon these findings, the present study was conducted. Studies were conducted in four, 45-m3 replicate recirculating systems at the USDA-ARS Sustainable Tank Aquaculture Recirculating Research Facility on the campus of Harbor Branch Oceanographic Institute at Florida Atlantic University. To initiate a 110-day rearing trial, juvenile pompano were stocked in two tanks of each of the four RAS at an initial nominal density of 6.5 (low density) or 13.0 kg/m3 (high density) – equivalent to 200 or 400 fish/tank, respectively. The mean weight of the fish at stocking was 259.0 ± 3.0 g. At initiation of the trial, 15 fish were collected and stored at -20° C for subsequent analysis of whole body composition. Fish were fed a commercial 50%-protein 14%-lipid 4.7-mm floating pelleted diet at a targeted daily feed rate of 3% body weight. Water temperature ranged 27.0-28.5° C. Salinity was maintained at 5 ppt. Standard procedures were used for determining production characteristics and proximate components of the fish and the diet fed during the rearing trial. Energy retention, protein efficiency ratio and protein productive value were also determined. Significant differences in mean weight and weight gain were evident between treatments on days 87 and 110. The 632.2-g final mean weight of fish reared at low density was greater than the 570.0 g for fish reared at high density. Weight gain for fish reared at low density (371.5 g) was greater than that for fish reared at high density (312.7 g). No differences in specific growth rate existed between treatments, although it decreased over the course of the trial. The final growth rates for fish reared at low and high density were 0.81 and 0.74%/day, respectively. The final absolute growth rate for fish reared at low density (3.4 g/day), however, was greater than the 2.8 g/day rate for fish reared at high density. Feed conversion efficiency decreased steadily with time, although no difference existed between density treatments until day 110. At that time, fish reared at low density exhibited 29.0% efficiency compared to 25.5% for fish reared at high density. No significant differences in whole body composition, energy retention, hepatosomatic index and fillet yield were observed between the treatments.