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Incidence of Renibacterium salmoninarum Infections in Juvenile Hatchery Spring Chinook Salmon in the Columbia and Snake Rivers
Author(s) -
Maule Alec G.,
Rondorf Dennis W.,
Beeman John,
Haner Philip
Publication year - 1996
Publication title -
journal of aquatic animal health
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.507
H-Index - 52
eISSN - 1548-8667
pISSN - 0899-7659
DOI - 10.1577/1548-8667(1996)008<0037:iorsii>2.3.co;2
Subject(s) - chinook wind , hatchery , oncorhynchus , fish hatchery , fishery , biology , juvenile , fish <actinopterygii> , spring (device) , veterinary medicine , ecology , aquaculture , fish farming , medicine , mechanical engineering , engineering
Abstract From 1988 through 1992, we assessed the prevalence (frequency of occurrence) and severity (degree of infection) of Renibacterium salmoninarum (RS) among fish in marked groups of Columbia River basin and Snake River basin hatchery spring chinook salmon Oncorhynchus tshawytscha before release and during their seaward migration. During the study, prevalence of RS infection decreased (from >90% to <65%) in six of the eight hatchery groups. We attributed this decrease to changes in hatchery practices that reduced vertical and horizontal transmission. Fish from Snake River hatcheries had a higher prevalence of infection when sampled at dams (mean >90%) than in the hatchery (mean <70%), but there were no differences in similar comparisons of Columbia River fish. Although prevalence and severity of RS infection were not correlated in the groups studied, it appears that fish from the Snake River were more severely infected than those from the Columbia River. Some groups of Snake River fish had higher severity of infection at dams than in the hatchery, but infection in fish from Columbia River hatcheries did not change. These differences between Snake River and Columbia River fish might have resulted from differences in river conditions and the distances from hatcheries to dams.