Salinity and temperature requirements for larviculture of the Monkey River prawn Macrobrachium lar (Fabricius, 1798) (Decapoda: Caridea: Palaemonidae)

Abstract

The present study investigated the effects of salinity and temperature on the survival and development of larvae of the Monkey River prawn Macrobrachium lar. Larvae of specific morphological development stages (zoeae I, III, V and VII) were exposed to various salinities ranging from 0 to 30±0.5‰ during salinity tolerance tests; while zoea I larvae were reared at temperatures of 26±0.5°C, 28±0.5°C, and 30±0.5°C during temperature tolerance tests.The results of the salinity tolerance tests demonstrated that newly-emerged larvae of Macrobrachium lar are able to tolerate fresh or brackish-water of approximately 10‰, but require gradually increasing salinities post-hatch reaching 30–35‰; which probably needs to be maintained until metamorphosis into post-larvae (PL). Larval stages I–II required a range of 10–15‰, III–IV required 15–25‰ and V–VI required 25–30‰. Stages VII to XIII required 30–35‰, following which salinity may be reduced after PL1. Larval survival and growth were found to be significantly reduced when maintained outside these salinities. Larvae kept in freshwater (0‰) die within 4days unless transferred to brackish-water.Results of the temperature tolerance investigations revealed that a temperature range of 30±0.5°C produced optimal survival and growth. As a result of the current investigation, baseline data on the salinity and temperature requirements of M. lar larvae have been collected and will be useful in further larviculture research work with this species. A salinity acclimation protocol has also been developed that will be useful in developing a mass culture technique for hatchery production of PL.