Abstract / Introduction / Summary:
Postmetamorphic ovigerous females of the mesoparasitic copepod Lernaea cyprinacea Linnaeus, 1758 (Lernaeidae) were collected from medaka, Oryzias latipes (Temminck and Schlegel, 1846) (Beloniformes: Adrianichthyidae), in Yahara Reservoir on Nakanoshima Island, one of the Oki Islands, located in the southern Sea of Japan off Shimane Prefecture, western Japan. Four (26.7%) of the 15 individuals of medaka were infected with 1–4 (mean, 1.8) females. Lernaea cyprinacea represents the first freshwater fish parasite found on the Oki Islands.
