Effect of monoalgal diet on the growth, survival and egg production in Nannocalanus minor (Copepoda: Calanoida)

Abstract

The effect of monoalgal diet on the growth, survival, egg production and egg hatching succession in calanoid copepod Nannocalanus minor was studied under laboratory condition. There are seven different microalgae such as Chlorella marina, Dunaliella salina, Isochrysis galbana, Nannochloropsis sp., Coscinodiscus centralis, Chaetoceros affinis and Skeletonema costatum were tested for their efficacy on survival of N. minor at two different algal cell concentrations viz. 10,000 and 20,000 cells/ml. Among the six diets tested, Chlorella marina shows the extensive survival in both lowest and highest algal concentrations where the 100% survival extends for 7th and 9th days of experiment while the least survival was obtained in diatom Skeletonema costatum. Likewise, copepod N. minor grew faster at C. marina than other algal feed tested presently. The egg production (32±1.52 eggs/female/day) and hatching succession (93.75%) both are proportionally increased with increasing algal concentration (20,000 cells/ml) while at low algal concentration (1000 cells/ml) it was recorded as 3±1 eggs/female/day and 44.33% respectively. The study provides a realistic basis for formulating suitable algal food and algal concentration required for copepod N. minor to achieve utmost growth, survival and fecundity in captive condition. This information can help in developing the culture technology on copepod Nannocalanus minor for it use in larval fish culture.