Investigation on Influences of Different Brackish Water Sources on Larval Quality and Developmental Indices of Freshwater Prawn (Macrobrachium rosenbergii)

The main objective of the present study was investigation on influences of different brackish water sources on freshwater prawn larval quality and developmental indices. For this study, along a larval period, four brackish water treatments with 12 PPT salinity including diluted marine water, brackish water from marine crystalline salt, brackish water with compounds of New formula and brackish water from municipal drinking water and kitchen salt were prepared; Then larval quality and developmental indices such as larval Stage index (LSI), Larval Condition Index (LCI), larvae dry weight, larval period long, tolerance to formalin stress (LC50-24 h) and survival rate were compared among these different treatments. The findings indicated that the balance of calcium and magnesium concentrations in brackish water is very important on growth, quality and larval development of freshwater shrimp larvae. The concentration of potassium ion between the Mysis and Zoa stages is very important on the larval development so that significant difference for LSI at 10 days post hatch in brackish water from New artificial formula is due to appropriate potassium concentration in it. Also the results showed that brackish water prepared from dilution of marine water is the best case for freshwater prawn hatchery and the brackish water from municipal drinking water and kitchen salt is not suitable for the hatchery; so brackish water prepared from dilution of marine water is suggested for the freshwater prawn larval period in hatcheries.