Effect of salinity on survival, growth, food consumption and haemolymph osmolality of the pink shrimp Farfantepenaeus subtilis (Pérez-Farfante, 1967)

The effect of salinity on survival, growth, food consumption and haemolymph osmolality was determined for the pink shrimp Farfantepenaeus subtilis in a series of independent experiments. The first experiment, shrimp at PL 50 were transferred without salinity acclimation from 30‰ to the salinities of 0, 5, 10, 15, 20, 25, 30 and 35‰ for 96 h. The tolerance of shrimp to abrupt changes in salinity (96 h LS 50) was estimated. The second experiment, growth and survival of shrimp were analyzed during 75 days in the treatments corresponding to the salinities of 5, 15, 25 and 35‰, where the food consumption was measured during four consecutive days. Finally, haemolymph osmolality of juveniles (1.23 g ± 0.26) maintained at 5, 10, 15, 20, 25, 30 and 45‰ for 24 h was evaluated. All PL 50 transferred from 30‰ to 0‰ died within 24 h, while survival after 96 h of those transferred to 5 and 10‰ was 96.6 and 86.6%, respectively. PL 50 transferred to salinities higher than 15‰ presented no mortality during the test. Based on these results, the lethal salinity (96 h LS 50) was estimated at 12‰. Final weight of shrimp reared at 25‰ was significantly higher than the other treatments, except for treatment 35‰, which did not differ from shrimp reared in salinity 15‰. Shrimp reared at 5‰ had the lowest weight. Survival of shrimp varied from 48% (15‰) to 65% (35‰), showing higher values at 25 and 35‰, but not differing significantly from 5‰. Shrimp reared at 25 and 35‰ had the highest food consumption values. The isosmotic point estimated from a regression between haemolymph and water osmolality was 377.07 mosM kg − 1 , which is equivalent to salinity 14‰. Results indicate that F. subtilis presents higher growth in salinities higher than its isosmotic point, i.e., at salinities above 25‰.