仔ガメの放流会はいかにあるべきか？

摘要

The sea turtle hatchling release program has been conducted all over the world for environ-mental education and as a subsequent result of artificial hatchery which is constructed to prevent wild nests from water exposure and egg predation. However, there has been a concern that sea turtle hatchlings released from a hatchery hours or days after emergence may change their swimming behavior. In order to determine what a sea turtle hatchling release program should be, this paper investigated the ontogenic change in offshore dispersal movement of green sea turtles (Chelonia mydas) from the shore during frenzy to the post-frenzy periods. Our results indicate that migration velocity decreased as turtles aged. Wave orientation behavior was not significantly different between growth stages, but the directional pref-erences of individuals toward waves tended to decrease with age, producing winding migration trajecto-ries in the older age groups. Thus, sea turtle hatchlings should be released as soon as possible to increase their survival and facilitate natural migration.