Susceptibility to the Agent of Amyotrophia among Japanese Black Abalone of Different Ages

Abstract

The disease of Japanese black abalone Nordotis discus discus called amyotrophia due to an unknown filterable agent has been prevailing mainly in juveniles. The difference in susceptibility to the agent of amyotrophia among Japanese black abalone of different ages (0, 1 and 2-year-old) was tested by immersion and intramuscular injection with the filtered (0.45 μm) homogenate prepared from diseased abalones. As the result, abalones of all ages tested were found susceptible to the agent of amyotrophia, although the susceptibility decreased with age of the shellfish.