Progress and constraints toward Commercialization of black sea bass aquaculture in the US: hatchery, NURSERY, growout and marketing
Presentation
Overview
Overview
Description
Black sea bass (BSB), Centropristis striata, is a heavily exploited marine finfish inhabiting continental shelf waters of the eastern US and the subject of state and federally supported aquaculture research. Recent progress in research and pilot commercial BSB aquaculture is reviewed. Protocols for hormone-induced spawning have been improved by optimizing dose of hormone administration to maximize egg and larval quality. Suitable environmental conditions and feeding regimens for larval culture have been delineated. In 2007, approximately 50,000 and 6,000 juveniles were produced in pilot-scale rearing trials at a commercial hatchery in NH (Great Bay Aquaculture) and a research hatchery at UNCW, respectively. Optimal protein level for growth of juvenile BSB fed a menhaden fish meal based diet is 44%, but high percentages of alternative plant (e.g. soybean meal at 60-70%) and animal protein sources (e.g. poultry byproduct meal at 60%) have been effectively substituted for fish meal, indicating an excellent potential for formulating sustainable practical feeds. Disparate rearing conditions have been used in independent studies on growout of hatchery-reared fingerlings to marketable stages, and significant variability in growth rates have been observed. In NC, BSB fingerlings (N = 3,300, mean wt. = 27 g, age = 125 d post-hatching) were stocked in a recirculating aquaculture system (RAS) consisting of two 16-m3 tanks and reared at an average of 21.0 oC and 33 g/L. Fish were fed a commercial diet (55% P, 18% L) and reached an average premium size of 682 g (range = 328-1,350 g) in 570 d (age = 695 dph) with 77% survival and a final biomass density of 52 kg/m3. In Georgia, however, BSB (N = 200, mean wt. = 100 g, age = 294 d) fed a diet of live juvenile tilapia in a RAS at an average of 24 oC and reached a mean of 900 g (range ?) in only 274 d (age = 568 dph), with growth presumably increased by diet and temperature. A prototype, closed (zero-discharge) marine RAS was tested for BSB growout in Raleigh, 150 mi from the ocean. In its 12th month of completely closed operation, the water renovation system (treating 24 g/L artificial seawater) has evolved to meet the challenges of a growing biomass of BSB. High variation in individual body weights among fish has been observed during BSB growout, suggesting that early culling of slow-growing fish will reduce growout time under practical culture. Pasteurellosis (Photobacterium damselae piscicida) was observed in subadult fish raised in RAS in NC and was remedied by lowering water temperature to 20-21 oC. Although etiology appeared to be non-pathogenic, exopthalmia (“popeye”) has been a recurring disorder in BSB raised in intensive RAS, but has caused relatively minor losses. Based on comprehensive marketing studies with aquacultured BSB, current annual niche market demand for fresh BSB (whole on ice @ $7.50 per lb) in the state of NC is estimated at 310,977 lbs. Out-of-state metro markets are under study and should boost demand. Pilot commercial project for BSB are underway in NC and in VA. Improving cost and availability of fingerlings, growth rates (via diet, selective breeding and sex control), and zero-exchange RAS technology are important keys to the transition from pilot- to full commercial scale production.
