Pasteurellosis in reared hybrid striped bass (Morone saxatilis x Morone chrysops)

An outbreak of a disease occurred in hybrid striped bass (20-25 cm in lengt h) Morone saxatilis x Morone chrysops cultured in Taiwan. No significant ex ternal sign was found, whereas prominent nodules were observed in internal organs, such as the spleen and kidney. The most severe histopathological ch anges were necrotic foci and multiple granulomas in haematopoietic tissues of the spleen and kidney. The results of biochemical examination and PCR-ba sed detection indicate that the disease was caused by Photobacterium damsel ae subsp. piscicida. This is the first reported outbreak of pasteurelosis i n cultured hybrid striped bass.