Abstract / Introduction / Summary:
An ovigerous female of Nerocila phaiopleura Bleeker, 1857 was found on one (prevalence, 0.7%) of 141 individuals of Japanese sardine Sardinops melanostictus (Temminck and Schlegel, 1846) from coastal waters of the western North Pacific Ocean off Mie Prefecture, central Japan, on 6 March 2015. The female was firmly attached using its dactyli to the host’s posterior body surface near the lateral line above the anal fin. A large oval-shaped wound with exposed muscles was found at the attachment site on the infected fish. Japanese sardine represents the fifth host record for N. phaiopleura from Mie Prefecture. In addition, based on the published information covering the period up to 2024, the distribution of N. phaiopleura in Japan is updated here. Most of the collection localities of the species exist in coastal Pacific waters of central and western Japan and the Seto Inland Sea. There are also two collection records of the species each from the East China Sea and the southern Sea of Japan. The species occurs in the waters affected by two warm currents, the Kuroshio, and its branch, the Tsushima Current.
