Fourth record of Lernaeenicus ramosus (Copepoda: Pennellidae) from grub fish Parapercis sexfasciata (Perciformes: Pinguiperidae) in Japan, and a discussion on the importance of grub fish as the host of the copepod

Abstract

Lernaeenicus ramosus Kirtisinghe, 1956 is a parasite of marine fishes in the Indo-West Pacific region. In Japan, this species has been reported from fishes in three families (Epinephelidae, Serranidae, and Pinguiperidae). In this study, we collected three metamorphosed females of L. ramosus from a grub fish Parapercis sexfasciata (Temminck & Schlegel, 1843) (Pinguiperidae) in Osaka Bay, part of the eastern Seto Inland Sea, off Awaji Island, Hyogo Prefecture, central Japan. This represents the fourth record for L. ramosus from grub fish in Japanese waters. Two of the three metamorphosed females of L. ramosus possessed paired egg sacs. From the present and other current records of L. ramosus, we infer that the parasite newly acquired grub fish as its host in the early 2000’s and has since utilized this fish species as a suitable host in coastal waters of Japan.