Abstract
Our previous investigation revealed that a new disease prevailing in Japanese flounder larvae (Paralichthys olivaceus) in Hiroshima Prefecture, Japan was a herpesvirus infection.Present paper describes the effects of water temperature and fish age on experimental infection of flounder larvae with the causative virus, and the susceptibility of other 5 species of marine fishes to the virus.
When exposed to the 0.45μm-filtrate of the diseased fish homogenate and kept at 20°C or 25°C, flounder larvae showed high mortalities (90-94%) within 9 days, while mortality was considerably delayed at 15°C. Larvae younger than 20 day-old (smaller than 9.5mm in total length) were highly susceptible but an abrupt decrease of susceptibility was found in fish of 23 day-old or older (bigger than 11.0mm). Any larvae and juveniles of other 5 marine fishes employed were not susceptible to the virus.
