DAO 43:211-215 (2000)  -  doi:10.3354/dao043211

A new strain of Cryptocaryon irritans from the cultured olive flounder Paralichthys olivaceus

Bo-Young Jee1,*, Ki Hong Kim2, Soo-Il Park2, Yi-Cheung Kim1

1Pathology Division, National Fisheries Research and Development Institute, 408-1, Kijang, Pusan 619-900, Korea
2Department of Aquatic Life Medicine, Pukyong National University, 599-1, Daeyun, Pusan 608-737, Korea

ABSTRACT: An obligate parasite, Cryptocaryon irritans, which is responsible for the white spot disease of marine fish is known to develop in the temperature regime over 19°C. Recently, however, we found white spot disease of olive flounder Paralichthys olivaceus during winter at water temperatures ranging between 12 and 16°C in Korea. In the present study we isolated a C. irritans-like ciliate from the affected fish and investigated its reproductive characters to compare the newly found ciliate with typical C. irritans. The newly found ciliate had an additional process in the reproductive stage, characterized by a budding before palintomic division, and it showed a higher ability to carry out tomitogenesis at a low temperature (16°C) than at a high temperature (24°C). Nevertheless, the present ciliates still had much in common with typical C. irritans with respect to clinical, histopathological, and morphological characters, suggesting that it is a new strain of C. irritans, adapted to lower water temperature.


KEY WORDS: Cryptocaryon irritans-like ciliate · White spot disease · Olive flounder


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