Occurrence of the parasitic copepod Acanthochondria spirigera (Chondracanthidae) on anglerfish Lophius litulon in the East China Sea off western Japan

東シナ海で漁獲されたキアンコウLophius litulonの口腔壁にカイアシ類ツブムシ科のトゲナシツブムシAcanthochondria spirigeraの寄生を認めた。キアンコウは本寄生虫の新宿主である。トゲナシツブムシを含むAcanthochondria属のカイアシ類は魚市場等で食品衛生的な問題を起こすことがあるため，その寄生状況を観察した。全検査魚における寄生率は72％で，キアンコウ1尾当たり普通1～2個体が寄生していた。寄生部位は口腔壁で，鰓への寄生は見られなかった。1尾当たり寄生数は魚体長が増すほど，また季節的には秋（9～11月）に多くなる傾向がみられた。

Anglerfish Lophius litulon (Jordan) caught commercially in the East China Sea off western Japan were found to be infected with the chondracanthid copepod Acanthochondria spirigera Shiino, 1955. Lophius litulon is a new host for this copepod. We made an observation on the occurrence of A. spirigera on anglerfish because the copepods of the genus Acanthochondria cause food hygiene problems at fish markets in Japan. Overall prevalence of infection with A. spirigera was high (71% of 31 fish examined), and one or two copepods were usually found on an infected fish. Their attachment site was the roof and floor of the buccal cavity of the fish. The number of copepods per fish showed an increasing tread with fish size and during the fall months (September to November).