Spread of Caligus sclerotinosus (Copepoda: Caligidae), a Pest of Cultured Red Seabream Pagrus major (Sparidae) to Korea

Abstract

Caligid copepods (Crustacea) are called as sea lice known to be pests of cultured fish, since they cause serious diseases and economic losses in fish aquaculture worldwide. However, the study on sea lice in Korean aquaculture is scanty. Caligus sclerotinosus Roubal, Armitage & Rhode, 1983 (Caligidae) is a parasitic copepod primarily infecting the highly prized cultured red seabream Pagrus major (Temminck & Schlegel, 1843) (Sparidae) in Japan, has been considered as a serious pest. Recently, in neighbouring Korea, red seabream culture has been carried out extensively and replaced with the yellow tail culture. However, until now, there have been no reports on caligid infection from the cultured red seabream in Korea. Our survey conducted in 2011 of 100 cultured individuals (range from 16¬ to 36 cm in total length) from Tongyeong floating net-cage fish farms, Gyeongsangnam-do, Korea resulted in severe infection of the sea louse C. sclerotinosus on the body surface of cultured red seabream. Prevalence was recorded as 100% and the maximum number of individuals per host was 22. Adult ovigerous females, males and few developmental stages were observed. The adults of C. sclerotinosus seem to undergo ontogenetic host switching after the final moult. It has a high host-specificity on cultured red seabream, but surprisingly not found on wild host collected from Tongyeong and Yeosu Fish Market