Adult snapper are generalized carnivores which, in the wild, feed largely upon crustaceans, molluscs, worms and fish. In culture, by day 2 snapper larvae absorb their yolksac. Their oil globule is absorbed at day 6 and feeding on rotifers usually commences at this day also (Battaglene & Talbot 1992). Snapper juveniles are fed rotifers at a density of 10/ml for days 4 - 27 after hatching. From days 23 - 40, juveniles are fed live Artemia at a density of 0.4 to 1.5 per ml. Live Tigriopus spp. copepods and frozen Brachionus spp, Artemia spp. and krill have also been utilized at various stages of larval development (Battaglene & Talbot 1992, Foscarini 1988, Smith & Hataya 1982). Snapper larval mortalities have been attributed to omega 3 highly unsaturated fatty acid (w3 HUFA) deficiency in cultured rotifers, consequently rotifers and artemia are enriched either with algae (such as Chlorella, Tetraseimis, Isochrysis or Pavlova spp.) or by encapsulation of artificial enrichment agents to overcome this deficiency (Battaglene & Talbot 1992). After metamorphosis, juvenile snapper will take inert food and may be weaned on to artificial pelleted diets at days 30 - 35 (Battaglene & Talbot 1992, Smith & Hataya 1982). Adult snapper can be fed on either artificial diets or on trash fish enriched with vitamins (Foscarini 1988). The time and expense involved in providing live food to snapper larvae have led to considerable research into developing suitable formulated micro particulate diets for snapper. Consequently, micro particulate diets are available commercially. Alternatively, proven formulations for producing artificial diets for snapper are readily obtainable (see Foscarini 1988). Artificial diets formulated for both juvenile and adult snapper involve high levels of protein, usually between 40% to 50%, fat at 3% to 6% and less than 20% carbohydrates. In general, a diet containing 46% to 50% protein is recommended for snapper and sea bream in Japan and Europe (Bell et all 1991, Foscarini 1988). |