ACCELERATION OF THE OCCURRENCE OF VIBRIOSIS IN AYU PLECOGLOSSUS-ALTIVELIS BY CYANOBACTERIAL PICOPLANKTON SYNECHOCOCCUS SP

Vibriosis in ayu Plecoglossus altivelis has occurred in Lake Biwa, Jap an, along with the blooming of cyanobacterial picoplankton. To search the factors accelerating the occurrence of vibriosis in ayu, the effec t of picoplankton on the mortality of ayu was investigated. Pretreatme nt of ayu with Synechococcus sp. clone P before infection accelerated the occurrence of vibriosis in experimental infections. Moreover, a hi gher number of Listonella anguillara adhered to the skin which was tak en from fish reared with clone P. These findings suggest that the acce leration of the occurrence of vibriosis by clone P is caused by facili tating the attachment of L. anguillara to the skin.