Effects of viruses infecting harmful algae HaV HcV and HcRNAV on bivalves zooplankton seaweeds fishes and a mouse

Abstract Harmful bloom-forming algae, Heterosigma akashiwo （Hada） Hada （Raphidophy-ceae） and Heterocapsa circularisquama Horiguchi （Dinophyceae） cause a mass mortality of cultured fish and bivalves, respectively. In recent years, a double-stranded DNA （dsDNA） virus HaV infectious to H. akashiwo, and a dsDNA virus HcV and a single-stranded RNA （ssRNA） virus HcRNAV, both infectious to H. circularisquama were isolated from natural seawaters in Japan. These viruses have some important characteristics suitable as micro-biological algicidal agents. However, from the viewpoint of risk management, evaluation of their effects on various organisms is essential to assess the possibility of their use for elim-inating the harmful algal blooms. In the present study, we have evaluated effects of the vi-ruses on marine organisms （bivalves, zooplankton, seaweeds and fishes） and mammals （a mouse）, and revealed that there was no significant acute toxicity against the tested organ-isms through the experiments. These results suggest that the algal viruses are safe for oth-er organisms.Key Words：Red tide, Algal virus, Acute toxicity, Safety