Pasteurellosis in Reared Hybrid Striped Bass (Morone saxatilis × Morone chrysops)

Abstract

An outbreak of a disease occurred in hybrid striped bass (20-25 cm in length) Morone saxatilis × Morone chrysops cultured in Taiwan. No significant external sign was found, whereas prominent nodules were observed in internal organs, such as the spleen and kidney. The most severe histopathological changes were necrotic foci and multiple granulomas in haematopoietic tissues of the spleen and kidney. The results of biochemical examination and PCR-based detection indicate that the disease was caused by Photobacterium damselae subsp. piscicida. This is the first reported outbreak of pasteurelosis in cultured hybrid striped bass.