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....
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...
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...
Anglers and naturelovers prize steelhead trout for their mystique and power. Oregon has two subspecies of steelhead (so-called because of the metallic appearance of maturing adults) or rainbow trout: a coastal form and an inland form.
This report the sizes for winter steelhead runs of the Willamette River and many of its tributaries from 1958-69, giving numbers and suggesting possible reasons for small runs.
Results of the first year of the Deschutes summer steelhead ecology and hatchery assessment. “This report covers the first year of a study of Deschutes summer steelhead ecology and factors limiting efficiency of hatchery production of summer steelhead smolts” (Contents).
Snorkel dive estimates and an inventory of stream habitat of the juvenile steelhead (Oncorhynchus mykiss) population in the Steamboat Creek basin were made in the summers of 1987 and 1988. Emigration was
monitored by fish trapping from spring through fall of 1988. Distribution, abundance, and habitat utilization of juvenile steelhead...
"This workshop was held to allow both research and management fish biologists to openly discuss the results of several ongoing projects designed to improve the way Oregon manages its steelhead populations." (from the Introduction) The report uses an extended abstract format.
Sympatric steelhead and resident rainbow trout (Oncorhynchus mykiss) are known
to exist in many rivers throughout the Pacific Rim. Whether sympatric steelhead and
resident rainbow trout are polymorphisms within a single gene pool or two reproductively
isolated populations has significant implications concerning the study and conservation of
this polytypic species....
A number of steelhead (Oncorhynchus mykiss) populations are at risk throughout Oregon, including five populations that are federally listed as threatened or endangered. However, little is known about behavior and survival of these fish as they transition from freshwater to seawater. We investigated whether estuarine survival varies on a temporal...