ABSTRACT
ABSTRACT Objective. The combined effect of salinity (25, 30, 35, and 40psu) and temperature (25, 30, and 35oC) was evaluated on survival and development from nauplii V (NV) larvae until postlarvae (PL1) of Litopenaeus vannamei. Materials and methods. Four replicates were applied to each combination of salinity and temperature. The larvae were placed in 12 L beakers a density of 100larvae/L. Salinity was increased dissolving commercial salt without iodine, into marine water, whereas fresh filtered tap water was used to decrease the salinity from seawater. The NV were adapted at 35psu and 30°C during 30 minutes. Thereafter, were transferred at each experimental combination of salinity and temperature. Every 24 h, samples of larvae were obtained to determine in vivo their stage of development and survival. All data were analyzed using a two-way ANOVA. Results. Survival and larval development were significantly (p<0.05) affected by salinity, temperature and interaction of both factors. Maximum ultimate survival to PL1 was obtained at 30°C and 30psu (82.2%) followed by 30 and 35°C at 25psu (71.5 y 71.6%). The highest development at PL1 was found at 30°C and 30psu (6.76). Larval development during experiment was lower at 25°C as compared to 30 and 35°C, regardless of the salinity levels. Conclusions. The most adequate conditions for survival and larval development were obtained between 30-35°C and 25-30psu.
RESUMEN Objetivo. Analizar el efecto combinado de salinidad (25, 30, 35 y 40 ups) y temperatura (25, 30 y 35°C) sobre la supervivencia y el desarrollo de larvas nauplio V (NV) hasta postlarvas (PL1) de Litopenaeus vannamei. Materiales y métodos. Los experimentos se realizaron por cuadriplicado por cada combinación de salinidad y temperatura. Las larvas se mantuvieron en acuarios de 12 L a una densidad de 100larvas/L. La salinidad se incrementó disolviendo sal granulada libre de yodo, a partir de agua de mar, mientras que para alcanzar las salinidades menores se utilizó agua dulce filtrada. Los NV aclimatados a 35ups y 30°C durante 30 minutos fueron transferidos a cada combinación experimental de salinidad y temperatura. Cada 24 h, se obtuvieron muestras de larvas para determinar in vivo su etapa de desarrollo y supervivencia. Los datos fueron analizados por un ANOVA de dos vías. Resultados. La supervivencia y el desarrollo larval fueron significativamente afectadas por la salinidad, temperatura y su interacción (p<0.05). La máxima supervivencia final a PL1 se obtuvo a 30°C y 30ups (82.2%), seguido por 30 y 35°C a 25ups (71.5 y 71.6%). El desarrollo más alto a PL1 fue encontrado a 30°C y 30ups (6.76). El desarrollo larval durante el experimento fue más bajo a 25°C en comparación con 30 y 35°C, independientemente de los niveles de salinidad. Conclusiones. Las condiciones más adecuadas para la supervivencia y desarrollo larval se obtuvieron entre 30-35°C y 25-30ups.