Fish, asymptomatically infected with Enteric Redmouth
Bacterium (ERMB), were tested for their ability to transmit
bacteria to non-infected fish. Unstressed carrier fish
were unable to transmit enough bacteria to cause
epizootics or produce carrier fish. However, when the
ERMB carriers were stressed with heat, sufficient bacteria
were shed to infect...
Crosses were made between a stock of summer steelhead (Salmo
gairdneri) known to be resistant to infection by Ceratomyxa
shasta and stocks of summer steelhead known to be susceptible.
Ceratomyxosis, the disease caused by C. shasta was initiated by
exposure to Willamette River water. I found that the crosses
were...
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....
The Nehalem and North Fork Nehalem rivers are the major tributaries of Nehalem Bay, an estuary on Oregon's north coast (Fig 1). The winter steelhead (Salmo gairdneri) and related fisheries of both streams have been the object of a study which began in 1972. Some data from creel surveys were...
Mean weights, lengths, and condition factors of three isozyme
phenotypes of lactate dehydrogenase (LDH) enzyme differed significantly
for experimentally reared winter steelhead trout (Salmo
gairdneri) fry. Time of emergence from the gravel was unrelated
to LDH phenotype. Relative mortality of the phenotypes between
eyed-egg stage and emergence was unaffected by...