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Tuberculosis in Pacific salmon and steelhead trout

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dc.creator Wood, James W.
dc.creator Ordal, Erling Josef, 1906-
dc.creator Oregon. Fish Commission
dc.date.accessioned 2006-09-18T22:39:24Z
dc.date.available 2006-09-18T22:39:24Z
dc.date.issued 1958-12
dc.identifier.other http://ir.library.oregonstate.edu/dspace/bitstream/1957/3066/1/TB_Pac_Salmon+Trout_ocr.pdf
dc.identifier.uri http://hdl.handle.net/1957/3066
dc.description.abstract Tuberculosis in salmonoid fishes was first observed in the 1952 run of fall chinook salmon (Oncorhynchus tshawytscha) returning to the Bonneville Hatchery of the Oregon Fish Commission. In the studies reported here, tuberculosis was found not only in adult spring chinook but in silver salmon (0. kisutch), blueback salmon (0. nerka), and in anadromous and resident strains of rainbow trout (Salmo gairdnerii). Advanced tuberculosis was found in salmonoid fishes held in fresh water for two years or longer, as well as in adults returning from the sea. Lesions were most frequently observed in the liver, and varied in size from small miliary tubercles to huge necrotic areas, filled with characteristic acid-fast bacilli. The typical bacilli were found in stained smears from the kidney, heart, musculature, brain, intestines, pyloric caeca, and roe of infected fish. The disease was originally observed in sexually-underdeveloped fish, and there is indication that it interferes with sexual maturation. It was found that tuberculosis in marked salmon known to be of hatchery origin was extremely high - in some cases 100 percent. Tuberculosis was absent in the small number of silver and chum salmon examined which were known to be the progeny from natural spawning. It is suggested that dissemination of the disease may be due to fish-cultural practices such as the feeding of untreated carcasses and the viscera from tuberculous fish. Since acid-fast bacilli were found in the roe of some fish, it is also suggested that the disease may be transmitted to healthy eggs during the process of fertilization. Tuberculous adult spring chinook were found less capable of surviving to maturity after they reached the spawning grounds than were non-infected fish. It is likely that tuberculosis also influences the ability of salmon to survive during earlier stages of their life history. The incidence of tuberculosis in adult spring chinook entering the Dexter holding ponds on the Middle Fork of the Willamette River in 1955 and 1956 was 8.7 and 6.1 percent, respectively. The increase in incidence to 58.8 percent in 1957 is attributed to the increased dependency of the run on artificial propagation necessitated by the construction of Lookout Point Dam. Among chinook caught in the Columbia River gill-net fishery in. February and in May 1956, 12.3 and 10.5 percent, respectively, of those examined were tuberculous. Although these are spring chinook, it is believed that hatchery reared fall chinook also entered the catch, especially during May, and may have contributed to the number of tuberculous fish taken. en
dc.description.tableofcontents Introduction -- Initial studies of tuberculosis in salmon -- Pathology and bacteriology -- Studies of tuberculosis in adult spring chinook salmon -- Comparative studies of tuberculosis in wild and hatchery fish -- Tuberculosis in steelhead trout -- Tuberculosis in adult fall chinook salmon -- Miscellaneous observations -- General discussion -- Literature cited. en
dc.format.extent 138281003 bytes
dc.format.mimetype application/pdf
dc.language.iso en_US en
dc.publisher Portland, Or. : Fish Commission of Oregon en
dc.relation.ispartofseries Contribution (Oregon. Fish Commission) en
dc.relation.ispartofseries no. 25. en
dc.subject Thematic Classification -- Plants and Animals -- Fish -- Anadromous Fish -- Chinook Salmon en
dc.subject Thematic Classification -- Plants and Animals -- Fish -- Anadromous Fish -- Coho Salmon en
dc.subject Thematic Classification -- Plants and Animals -- Fish -- Anadromous Fish -- Steelhead Trout en
dc.subject.lcsh Pacific salmon -- Diseases -- Oregon en
dc.subject.lcsh Steelhead (Fish) -- Diseases -- Oregon en
dc.subject.lcsh Tuberculosis in animals -- Oregon en
dc.title Tuberculosis in Pacific salmon and steelhead trout en
dc.type Technical Report en
dc.description.peerreview no en
dc.coverage.spatialstates Spatial: States -- Oregon en
dc.relation.reportsandpublications Reports and Publications -- Other Reports and Publications en

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