The effects of salinity on the development of giant freshwater prawn, macrobrachium rosenbergii larvae

Macrobrachium rosenbergii is a giant freshwater prawn and is the largest family in the genus Palaemonidae. This species has high demand and high market value. It is also commonly used in aquaculture industry. Eggs M. rosenbergii are round shaped with a size of 0.6 mm to 0.7 mm and it is orange colored during lay-out and turn into dark gray 2 or 3 days before hatching. Eggs M. rosenbergii will take 1 or 2 nights in the process of hatching with optimum salinity levels to produce larvae. M. rosenbergii larvae are planktonic and swimming with his body in reverse. It needs brackish water to survive. The aims of this study were to investigate the optimum water salinity rate for growth M. rosenbergii larvae and to observe the larvae development by stage 1 to stage 11. There were 11 stages of M. rosenbergii larvae and each stage change was preceded by skin replacing. Each stage has a recognizable characteristic. Stage 1 of larvae is 2 mm long while at stage 11 is 7 mm. This process takes 20 to 40 days. The study was conducted in 15 litter plastic tank (12cmX18cmX12cm) with maintain the temperature at 28 degree celcius (room temperature) and different rate of salinity (8, 10 and 12 ppt). The level of survivality of larvae it was observed and monitored manually. Finding from this study showed that the optimum water salinity in development and resistance for M. rosenbergii larvae were 10 ppt. However, the optimum rate of water salinity for larvae survivability was 8-12 ppt. In addition, the optimum salinity needed to be maintaining for the larval development.