Cost comparisons of rearing larvae of freshwater shrimp,Macrobrachium acanthurus and M. rosenbergii,to juveniles

Costs were determined for rearing larval Macrobrachium rosenbergii (De Man) and M. acanthurus (Wiegmann). Rearing was conducted in two phases. First-phase rearing (first 10 days) was conducted in conical fiberglass tanks with recirculated, filtered, brackish water; second-phase rearing (final 30 days) was done in aerated 1 000-l concrete tanks. To minimize water quality problems and debris accumulation in second-phase rearing, larvae were transferred every 4 to 5 days to a new tank of clean water. Larval food consisted of newly hatched Artemia and either freshly ground fish or freeze-fried fish.Mean survival in five M. rosenbergii rearing trials was 43% in 40 days at a final density of 12 juveniles per liter. Mean survival of four M. acanthurus trials was 25% in 44 days at a final density of 3 juveniles per liter. Average total cost of labor, operation (electricity), food and water per thousand juveniles produced was $3.56 for M. rosenbergii and $13.42 for M. acanthurus.Extrapolation of results to larger (3 000-l) second-phase rearing tanks showed M. rosenbergii rearing cost could be reduced to $\text{\$1.87}\text{1 000}$.