Effects of diet on survival and growth of the Atlantic silverside

Effects of two live and seven prepared diets on the survival and growth of postlarval and juvenile Atlantic silversides (Menidia menidia) were determined. Two experiments were conducted, one with 23-day-old postlarvae and one with 57-day-old juveniles. In both experiments, growth rate and survival were greatest on the live diet of brine shrimp (Artemia salina) nauplii. Survival was lowest on a prepared diet originally designed for freshwater fish species. Growth was similarly low for all lots fed prepared diets. A commercial flake food was the best of the prepared diets tested. Response to the diet was more sensitively reflected in growth than in survival. Younger fish showed a greater and more immediate growth response to diets than did juveniles. Postlarval fish that were fed brine shrimp gained 36.6 mg (from an initial body wet weight of 9.3 mg), whereas those fed the flake diet gained 4.5 mg. The reduced growth and survival of fish fed the artificial diets cannot be attributed to a single nutritional deficiency.