Effect of the Initial Stocking Body Weigth on Growth of Spotted Rose Snapper Lutjanus Guttatus (Steindachner, 1869) in Marine Floting Cages

Pargos lunarejos con pesos promedio de 24,5 ± 3,7 g, 55,4 ± 3,5 g y 110,2 ± 4,6 g fueron introducidos para su engorde en jaulas flotantes de 100 m3 por un lapso de 153 días en Santa Cruz de Miramar, Nayarit, México, con la finalidad de encontrar el peso más adecuado de cultivo. Los pargos fueron alimentados dos veces al día con alimento comercial conteniendo 35 y 25% de proteína cruda durante el primero a tercer mes y en el cuarto y quinto mes respectivamente. Durante el experimento, la temperatura del agua varió de 25,6 a 32,3ºC. Al final del experimento se obtuvo una supervivencia que fluctuó de 67,5 a 74,7%. Se determinaron, con base en el peso inicial, diferencias estadísticamente significativas (P≤0,05) con respecto a la biomasa final cosechada. La máxima ganancia en peso promedio semanal fue de 12,8 g semana-1 en los organismos con el mayor peso inicial (110,2 ± 4,6 g). Esta información sugiere que la inclusión de pargos lunarejos con un peso de 110 g puede ser una buena estrategia para el engorde en jaulas flotantes

Effect of Stocking Density on Growth and Survival of the Prawn Macrobrachium tenellum Cultured in a Cage-Pond System

Freshwater prawns, Macrobrachium tenellum, were reared at four stocking densities (6, 12, 18, and 24 prawns/m3), with three replicates each, in 12 bottom cages of 3 m3 capacity that were placed in a 1,422-m2 earthen pond. The growth, weight gain, production, specific growth rate (SGR), feed conversion ratio (FCR), and survival of the prawns were determined. We stocked 540 juveniles that had an average weight of 1.57 ± 0.09 g (mean ± SE) for 180 d and fed them twice a day with commercial shrimp pellets containing 35% crude protein. Water quality variables were measured during the study. All of the growth and production parameters were affected by stocking density (P < 0.05). The mean weight and SGR increased at low densities. The lowest mean weight (17.2 ± 2.0 g) was observed at the higher density (24 prawns/m3), although production increased at high densities and varied from 1,307.2 kg/ha at a density of 6 prawns/m3 to 2,013.3 kg/ha at a density of 24 prawns/m3. Survival varied from 79 ± 1% at a density of 6 prawns/m3 to 47.5 ± 0.6% at a density of 24 prawns/m3. The overall results suggested that stocking density affected the growth and survival of M. tenellum cultured in the cage-pond system. The initial stocking density represents a very important culture variable in terms of marketing for this freshwater prawn because at all tested densities the prawns reached their individual market size.Received July 11, 2013; accepted December 27, 2013. © 2014 © American Fisheries Society 2014