The use of some age determination methods may result in the
incorrect age structure of fish populations. This in turn may lead
to incorporation of inappropriate data into models used for stock
management. Otoliths are commonly used for determining the age of
fishes, and ages based on the whole otoliths...
An increase in frequency and severity of hot, dry summers has been associated with a dramatic shift in the coniferous forests of western Oregon’s valleys, especially on the privately-owned properties along the low-elevation edges of these valleys. Various conifer species, including Douglas-fir (Pseudotsuga menziesii), are declining in these forests, leaving...
Methods and utility of age determination of yellowtail rockfish
(Sebastes flavidus), canary rockfish (Sebastes pinniger), and black
rockfish (Sebastes melanops) collected off Oregon during 1972 to
1975 are discussed. Structures compared on the basis of the reproducibility
of counts of annuli (consistency of readings) were the anal fin
pterygiophore, opercle,...
Juvenile coho salmon (Oncorhynchus kisutch) and steelhead trout
(Salmo gairdneri) of different stocks and three transferrin genotypes
(AA, AC, and CC), all reared in identical or similar environments, were
experimentally infected with the causative agent of bacterial kidney
disease (BKD) or Vibrio anguillarum. Mortality due to the pathogens
was compared...
Oregon Department of Fish and Wildlife trout broodstocks from Alsea, Cole Rivers, Klamath, Leaburg, Oak Springs, Roaring River and Willamette Fish Hatcheries were examined for the presence of myxosporidans. Wild fish collected from waters above these hatcheries were also examined. Seven species of myxosporidans were observed in the hatchery broodfish:...