2005 Volume 53 Issue 1 Pages 91-92
The transmission period of the unidentified filtrable causative agent of amyotrophia in the juvenile Japanese black abalone Haliotis discus discus was examined. The juvenile abalones reared in ultraviolet irradiated sea water were exposed to non-UV treated sea water for 10 days in different dates (January 18-28, January 29-February 8, February 9-19 or February 19-, in 2002) . They were sampled for observations of the typical histopathological changes of amyotrophia in April and May. The histopathological changes were observed in the groups of abalones exposed to non-UV treated sea water after February 9, but no changes in the groups exposed from January 18-28 or January 29-February 8. From the results, it was suggested that the transmission of amyotrophia via rearing sea water occurred during a particular period from the late winter to the early spring in Kagoshima Prefecture.
