Effect of temperature, salinity and algal food concentration on population density, growth and survival of marine copepod Oithona rigida Giesbrecht

In the present study the copepod, Oithona rigida was reared successfully fed with different algal diets such as Chlorella marina, Coscinodiscus centralis, Skeletonema costatum and Chaetoceros affinis in the hatchery condition. The total mean production of different stages of O. rigida viz., nauplii, copepodid and adults were: 21120.79, 8205.6 and 4949.9 L-1 respectively. Maximum density (3679.3 L-1) of nauplii was attained on 11th day of culture. The egg diameter of O. rigida was reported as 0.003 mm, just hatched nauplius (Nauplius I) and last nauplius (Nauplius VI) were 0.098 and 0.184 mm respectively. The length of early copepodid and the adult female and male were 0.312; 0.745 and 0.699 mm respectively. It is inferred that the water quality parameters such as temperature, salinity and algal prey essentially influenced the population, growth and survival of O. rigida in captive condition. The density obtained during the two months culture period indicated that, O. rigida is more sufficient for commercial seed production of fish and crustacean larvae.