Fin lesions induced by Nerocila japonica (Isopoda: Cymothoidae) in a yellowfin seabream, Acanthopagrus latus, from Hiroshima Bay, Japan, with a review of pathological impacts of cymothoids on the skin of Japanese marine fishes

Abstract

Two individuals (one ovigerous female and one male) of the cymothoid isopod Nerocila japonica Schioedte & Meinert, 1881 were found on the left pectoral fin of a yellowfin seabream, Acanthopagrus latus (Houttuyn, 1782), in coastal waters of Hiroshima Bay, an inlet of the western Seto Inland Sea, Hiroshima Prefecture, Japan. The fin was seriously damaged, and the fin membrane was mostly lost. A wound with exposed fish muscle was also found at the base of the fin. These lesions are considered to have been caused by the isopod’s pereopod insertion to and feeding on the host’s tissues. Previous studies on the pathological impacts of cymothoid isopods on the skin of Japanese marine fishes are reviewed.