34 DECEMBER 2015 • WORLD AQUACULTURE • WWW.WAS.ORG Protein is the most expensive nutrient in fish feeds, representing from 30 to 60 percent dry weight. Fishmeal is typically used as the main protein source in formulated feeds due to its high nutritive value and palatability. Finding alternatives to fishmeal is needed to reduce costs and reliance on this expensive and finite protein source. Soybean meal is considered to be one of the most suitable alternative ingredients for replacing fishmeal in fish feed. Laboratory studies at the University of North Carolina Wilmington (UNCW) have demonstrated that, for a 45 percent crude protein diet, 70 percent of the fishmeal can be replaced by soybean meal without amino acid supplements in diets for black sea bass and 40 percent of the fishmeal can be replaced by soybean meal without amino acid supplements in diets for southern flounder (Alam et al. 2011, 2012, Sullivan 2008). Laboratory findings revealed the potential for substantial reductions in feed costs for commercial aquaculture of black sea bass and southern flounder using alternative plant protein sources to fishmeal. Studies are needed to test the most promising diets on pilot and commercial scales. It is important, therefore, to test optimal diets developed for juveniles in the laboratory for fish performance through to market size. The black sea bass Centropristis striata (Fig. 1) is a high-value marine finfish that inhabits continental shelf waters from Maine to northern Florida. Black sea bass are heavily exploited south of Cape Hatteras and fishery regulations are becoming more restrictive (NCDMF 2009a), with commercial landings unable to satisfy increasing consumer demand. There is increasing interest in aquaculture production of black sea bass due to its high market price and the increasing level of technical information about its culture. Based on research supported by NOAA, NC Sea Grant and USDA, technology for producing embryos, rearing larvae through juvenile stages and raising fingerlings to market size in intensive recirculating aquaculture system (RAS) have been developed (Copeland et al. 2002, 2005, Alam et al. 2008, 2012, Watanabe 2011). Cultured black sea bass have been test-marketed throughout North Carolina and in metropolitan markets of the northeast (Philadelphia, New York) and is considered to be of exceptional quality (Dumas and Wilde 2009). Black sea bass is now in the transition phase between research and commercial production in the southeastern US. The southern flounder Paralichthys lethostigma (Fig. 2) is a highly-valued recreational and commercially over-harvested Pilot, Commercial-Scale Testing of Promising Diets for Intensive Cultivation of Black Sea Bass and Southern Flounder Md. Shah Alam, Wade O. Watanabe, Mathew Dawson and Patrick Carroll FIGURE 1. Black sea bass at Aqua Plantations, Wilmington, NC. Protein is the most expensive nutrient in fish feeds, representing from 30 to 60 percent dry weight. Fishmeal is typically used as the main protein source in formulated feeds due to its high nutritive value and palatability. Finding alternatives to fishmeal is needed to reduce costs and reliance on this expensive and finite protein source. Soybean meal is considered to be one of the most suitable alternative ingredients for replacing fishmeal in fish feed.
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