抄録
Abstract: Recently, most populations of amphioxus in Japan, consisting of the species Branchiostoma belcheri Gray, have been thought to be in decline or already disappeared, because there have been few collection records in their known habitats. In the offing of Koajiro Bay and Moroiso Bay at Misaki on the Miura Peninsula in Kanagawa Prefecture, amphioxi were again found in 1996 almost twenty years after their last collection. Three juveniles settled in the bottom of Moroiso Bay were collected by dredging in November 1996, and swimming larvae were collected by towing a plankton net in October 1996 and September 1997. The sediment condition in the offing of Misaki was analyzed on the basis of dredge samples and observed using an underwater video camera. These investigations suggest that many habitats of amphioxus still exist along the Japanese coasts.
