Seasonal distribution pattern of adult sea cucumber Apostichopus japonicus (Stichopodidae) in Yoshimi Bay, western Yamaguchi Prefecture, Japan

To examine the distribution pattern of adult Apostichopus japonicus, approximately monthly surveys were conducted during a 2-year period in the subtidal zone of a harbor area in Yoshimi Bay, western Yamaguchi Prefecture. Results showed a clear seasonal change in distribution pattern: many animals were distributed on the seabed and the lower part of a jetty during winter to spring, whereas most animals occurred on the upper part of a jetty during summer to autumn, namely, the aestivation season. Such change is considered to be due to the migration of animals within the present study site.