Body length variation in the marine fish ectoparasite Ceratothoa oxyrrhynchaena (Isopoda: Cymothoidae) in relation to host body size

抄録

The cymothoid isopod Ceratothoa oxyrrhynchaena Koelbel, 1879 was collected from the buccal cavity of yellowback sea-bream, Dentex hypselosomus Bleeker, 1854, in the southern Sea of Japan. There was a linear positive relationship between isopod body length (female, 22.6–35.0 mm; male, 9.6–17.0 mm) and fish standard length (115–249 mm). Body lengths of paired female and male isopods were also correlated with each other. These results indicate that isopods parasitized smaller fish than those examined and grew steadily as their hosts grew. This paper also suggests that the isopod can stay over three years in the buccal cavity of fish.