Flavobacterium psychrophilum in Baltic salmon Salmo salar brood fish and their offspring

E Ekman, H Börjeson, N Johansson
1999 Diseases of Aquatic Organisms  
814 94 ~l v k a r l e b y , Sweden ABSTRACT: Baltic salmon brood fish were investigated for the presence of Flavobacterium psychrophilum in the kidney, spleen, brain and sexual products (ovarian fluid, unfertilised eggs and milt). Samples for bacteriology were taken at capture, when the fish were ascending their native river to spawn, and after a period of captivity in indoor pools, at stripping. During captivity, abnormal wiggling behaviour was recorded in some of the fish. Bacterial samples
more » ... re taken to determine if F. psychrophilum had any role in the aetiology of the condition. Furthermore, the presence of F. psychrophilum on egg surfaces during incubation was investigated. F psychrophilum was isolated from internal organs and/or sexual products in 7 out of 50 (14.0%) fish sampled at capture and 63 out of 272 (23.2 %) fish sampled at stripping. The bacteria was isolated from either spleen or gonads in 2 out of 19 (10.5%) fish with abnormal wggling behaviour but no bactena was isolated from the brain. No F psychrophilum was isolated from eggs at the eyed stage. Just before hatching, the bacterium was isolated from 5 out of 15 (33.3%) family groups. The present study shows that Baltic salmon brood fish are carriers of F. psychrophilum during their spawning migration. m e presence of the bacteria in sexual products from both females and males indicates that transmission from the brood fish to the offspring should be considered an important route of infection. KEY WORDS: Flavobacterium psychrophilum -Baltic salmon . Brood fish . Eggs . Milt . Ovarian fluid O Inter-Research 1999 Resale of full article not permitted
doi:10.3354/dao037159 pmid:10546045 fatcat:l4g4sunbwnh65e537oakv2fal4