Optimization of culture conditions for marine copepod Macrosetella gracilis (Dana, 1847) with emphasis on salinity and algal diets

Abstract

The effects of salinity and algal diets on the survival, egg production and population density of harpacticoid copepod, Macrosetella gracilis were studied. Seven different salinity levels (15, 20, 25, 30, 35, 40, 45 ppt) and six different algal diets (Chlorella marina (CHL), Isochrysis galbana (ISO), Dunaliella salina (DUN)., Nannochloropsis salina (NAN)., Tetraselmis suecica (TET). and mixed algal diet (combination of above mentioned microalgae)) were analyzed in this study. Highest (p < 0.05) nauplius production rate (NPR), survival rate (SR) and population density (PD) were achieved by copepod reared under 30-35 ppt salinity. Diet experiments showed that feed can significantly affects the NPR, SR and PD of M.gracilis. The highest NPR (66.3±4.9 nauplius female−1 day−1) was produced by mixed algal diet treatment followed by other feeds in descending order ISO (63.6±4.9), CHL (39±2.8), DUN (26.3±3.14), TET (26.3±2.25) and NAN (18.6±7.4 nauplius female−1 day−1). Among the individual feeds tested, ISO induced best survival (89%) followed by CHL (75%) and TET (69%). This study revealed that M. gracilis can be mass cultured for commercial purposes and has a great potential for use in toxicity studies due to its high reproductive performance and wide range of tolerance to local environmental conditions.