DAO 34:161-166 (1998)  -  doi:10.3354/dao034161

Vibrio viscosus in farmed Atlantic salmon Salmo salar in Scotland: field and experimental observations

D. W. Bruno*, J. Griffiths, J. Petrie, T. S. Hastings

FRS Marine Laboratory, PO Box 101, Victoria Road, Aberdeen AB11 9DB, Scotland

ABSTRACT: Winter mortality occurred in market-sized (2 to 3 kg) Atlantic salmon Salmo salar reared in sea cages in Scottish waters. Many of the fish had skin ulcers. Internally prominent dark-brown petechiae or ecchymotic haemorrhage was observed. Splenomegaly was associated with congestion and widespread necrosis. A Vibrio sp. was isolated from internal organs. Biochemically isolates of the bacterium were similar to a previously described bacterium, Vibrio viscosus, recorded in a phenotypic study from farmed salmon in Norway. This work examines the occurrence of V. viscosus in marine-reared Atlantic salmon for the first time in Scottish waters. An experimental study reproduced the field observations and Koch's postulates were fulfilled. The histopathology associated with natural infection was compared with that in laboratory-infected fish.


KEY WORDS: Atlantic salmon · Salmo salar · Vibrio viscosus · Pathology · Experimental infection


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