<技術・研究報告>和歌山県田辺湾で1997年の4月から9月までに採取された日本初記録種を含むヒドロクラゲ類(刺胞動物門、ヒドロ虫綱)

Abstract

At least 55 species of hydromedusae (Cnidaria, Hydrozoa), including two species new to Japan (Amphicaryon acaule and Cladosarsia sp.) and a species new to Tanabe Bay (Ectopleura dumortieri), were collected between April and September, 1997, at four stations 20-54 m deep inside and outside of Tanabe Bay, Wakayama Prefecture, Japan. The data are based on 88 vertical tows, each done using two different kinds of small open net (mesh sizes: 0.344 mm and 0.222 mm), conducted on 11 days during the study period (1-3 days/month); at each station, two sets of tows were taken on each occasion in the daytime. Twenty anthomedusan species, nine leptomedusan species, one limnomedusan species, 18 siphonophoran species, five trachymedusan species, and two narcomedusan species were recorded, and their occurrences by month and station are listed. Mature medusae were noted for 25 species, and 19 species were represented by a single individual each. Based on such data, the likely provenance of various species is discussed. These records supplement previous reports of the hydrozoan fauna of Tanabe Bay that were serially published in the present journal from 1995 until 2003.