Two eight-week feeding studies were conducted with juvenile red drum to determine the maximum levels of soybean meal that may replace fish meal in diets containing 38 percent crude protein, without reducing weight gains. Results indicated that fish fed diets containing up to 90 percent of the protein from soybean meal gained as much weight as fish fed a diet with 100 percent of the protein from fish meal, however, fish fed a diet with all of the protein from soybean meal gained significantly less. Supplementing the diet with 90% of the protein coming from soybean meal with 2 percent glycine or fish solubles tended to increase gains compared to fish fed a diet with the supplements. In both experiments there was greater consumption of the soybean meal-containing diets compared to fish fed diets with all of the dietary protein coming from fish meal. The researchers conclude that a minimum of 10 percent fish meal protein appears necessary in practical diets containing most of their protein from soybean meal to maximize growth and feed utilization for red drum.

McGoogan, B.B. and D.M. Gatin. 1997. Effects of replacing fish meal with soybean meal in diets for red drum (Sciaenops ocellatus) and potential for palatability enhancement. J. World Aquaculture Soc. 28(4):374-385.