Differences of reproduction of Calanus sinicus fed with two species of algae

The effects of two algae (Phaeodactylum tricornutum and Isochrysis galbana) on reproduction of copepod (Calanus sinicus) were investigated in laboratory. The results showed that the average egg production of Calanus sinicus fed with diatom (Phaeodactylum tricornutum) was 0.24±0.07/d, with the survival rate of female being relatively low. In contrast, relatively high egg production (7.844±1.12/d ) and survival rate appeared in Calanus sinicus fed with flagellate (Isochrysis galbana). In addition, the egg hatching rates of Calanus sinicus fed with Phaeodactylum tricornutum were lower than those of Calanus sinicus fed with Isochrysis galbana either in algal suspension or in filtered seawater. It was evident that diatom Phaeodactylum tricornutum could produce some inhibitory effect on both fecundity and hatching of Calanus sinicus, compared to Isochrysis galbana. Through fatty acid composition analysis, it was found that Phaeodactylum tricornutum was inferior in contents of polyunsaturated fatty acids (PUFAs) and some specific fatty acids(ω3,ω6) which are necessary to copepod reproduction.