Effect of algal diets on growth of Calanoid copepod, Acartia tonsa (Dana, 1896)

Abstract

The effect of different algal diets on the growth of copepod Acartia tonsa was investigated under laboratory conditions. Copepod were fed for fifteen days with seven algal diets which included three mono-algal diets such as Isochrysis sp. (T1), Chaetoceros sp. (T2) and Tetraselmis sp. (T3), and four mixed algal diets such as Tetraselmis sp. and Isochrysis sp. (T4); Tetraselmis sp. and Chaetoceros sp. (T5); Isochrysis sp. and Chaetoceros sp. (T6) and Tetraselmis sp., Isochrysis sp. and Chaetoceros sp. (T7) in water of temperature 25±1^oC and salinity of 20 ‰ with treatments in triplicates. Copepod fed mono-species algal diet Isochrysis sp. produced the highest mean body length at the early stage of culture. Growth was highest in copepod fed mixed algal diet of T7, while the least growth was observed in copepod fed mixed algal diet of T6. However, growth in copepod fed mixed algal diets of T7 and T4 were not significantly different (P>0.05). The study showed the viability of the local alga Isochrysis as food item both as mono-algal diet and in mixed algal diets for optimal growth of copepod Acartia tonsa. This makes the culture of the copepod a promising live feed in aquaculture practices in Nigeria.

Keywords: Tetraselmis sp., Isochrysis sp., Chaetoceros sp., f/2 medium and Conwy medium