Pelagic microalgae as suitable diets for the benthic harpacticoid copepod Tigriopus japonicus

It has been reported that certain microalgae have the ability to cause various negative effects on pelagic calanoid copepods. However, whether such pelagic microalgae have similar negative effects on benthic copepods has had little attention. The results of the present study indicated that both benthic naupliar and copepodite stages of the harpacticoid copepod Tigriopus japonicus could effectively utilize five species of pelagic microalgae to complete their development. The effects of different concentrations of various microalgae species on naupliar survival were significant; however, no significant effects on copepodite survival were detected. When fed with two diatoms Chaetoceros muelleri and Skeletonema costatum as well as the dinoflagellate Prorocentrum micans and the chrysophyte Isochrysis galbana at high concentrations (a parts per thousand yen8.50 mu gC ml(-1)), the survival of both naupliar and copepodite stages of T. japonicus was more than 90%. However, when the diatom Nitzschia closterium f. minutissima was fed at the high concentrations of 8.50 mu gC ml(-1), the naupliar survival was 76.3 +/- A 3.2 %. Interestingly, the negative effects of N. closterium f. minutissima as a diet in the naupliar stage did not affect the survival of the copepodites, which may be explained by increased mobility of copepodites.