2023 年 18 巻 4 号 p. 190-197
During an ROV Hyper-Dolphin dive to bathyal depths in the Kamaishi Marine Canyon, off Tohoku District, the north Pacific, the association of a large specimen of Caprella (Crustacea: Malacostraca: Amphipoda) was observed, surrounded by juveniles, clinging to the dorsal tube feet of the deep-sea holothurian Scotoplanes globosa (Théel, 1879) at 1142 m depth. Scotoplanes globosa “walks” on the seafloor using long tube-like limbs extending from its body. The present observation indicated that “walking” deep-sea holothurians are an underrated substrate for Caprella spp. in the bathyal depths. Approximately 25 juveniles were collected with the mature female specimen from the same holothurian. These individuals were identified as Caprella fimbrillata Vassilenko, 1993 which has previously been reported from the eastern seaboard of Etorofu/Iturup Island, Chishima/Kuril Islands, in 605 to 1200 m water depth; these sites are located approximately 600 km northeast from the present site off Tohoku in the northwest Pacific. The mature female was closely surrounded by juveniles on the same deep-sea holothurian, suggesting maternal care by the mother caprellid in the bathyal depth environment.
