Culture of Florida red tilapia in marine cages: the effect of stocking density and dietary protein on growth

Growth survival and feed conversion were studied in juvenile, monosex male Florida red tilapia (8.78 g average wt.) held in sea cages on Great Exuma, Bahamas. Twenty-four floating cages (1 m 3) were anchored in a sea pass and stocked at densities of 100, 200, and 300/m 3 and fed 84 days on commercially prepared diets containing 28 or 32% protein. Final mean weights were higher for fish fed the diet with 28% protein (average=176.8 g) than those fed at 32% protein (average=166.4 g), under all densities. Final biomass densities increased with increasing stocking density (range=16.1–52.2 kg/m 3) and were higher for fish fed the 28% protein diet than those fed the 32% protein diet under all densities. Daily weight gain (average=1.94 g/day), specific growth rate (average=3.54%/day), and survival (average=97.9%) were higher and feed conversion ratios (average=1.88) lower for fish fed the 28% protein diet than for those fed the 32% protein diet under all densities. No significant effects of stocking density on these parameters were observed. A significant effect of stocking density on final size variation was evident, with greater coefficients of variation of body weights and lengths among fish reared at a density of 100/m 3 (average=26.0%; 8.51%) than among those reared at higher densities (average=20.8%; 6.87%). In-cage dissolved oxygen fell to