February 15-18, 2009 Washington State Convention Center Seattle ...

PROGRESS AND CONSTRAINTS TOWARD COMMERCIALIZATION OF BLACK SEA BASS
AQUACULTURE IN THE US: HATCHERY, NURSERY, GROWOUT AND MARKETING
W. O. Watanabe*, M. S. Alam, C. F. Dumas, R. F. Lee, T. M. Losordo, D. DeLong, D. Berlinsky, G. Nardi,
C. D. Bentley, T. C. Rezek, K. Sullivan, J. Wilde and A. Myers
University North Carolina Wilmington (UNCW)
Center for Marine Science
601 S. College Rd.
Wilmington, NC 28403-5927 USA
watanabew@uncw.edu
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 are 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 juveniles were produced in pilot-scale trials at a commercial hatchery in
NH (Great Bay Aquaculture). Optimal protein level for growth of juvenile BSB fed a menhaden fish meal based diet is 44%,
but a high percentage (60-70%) of soybean meal has 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-m 3 tanks and reared at an average of 21.0 o C 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/m 3 . In GA, 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 o C reached a mean of 900 g 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. In BSB, protogynous hermaphroditism can be disrupted in
culture, with individuals differentiating first as males showing faster growth. 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 infrequently observed in subadult fish raised in RAS
in NC and was remedied by lowering water temperature to 20-21 o C. Although etiology appeared non-pathogenic, exopthalmia
(“popeye”) has been a recurring disorder in BSB raised in intensive RAS, but causing minor losses to date. Based on comprehensive
marketing studies, 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 domestication
and sex control), zero-exchange RAS technology, and development of sustainable feeds are keys to the transition from pilot to
commercial scale production.
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