This report summarizes the 1979 ocean salmon fishing season off the Oregon coast. Troll fishery landings were obtained directly from commercial fish receiving tickets supplemented with a survey of fish buyers to obtain the most up-to-date estimate of total landings. Recreational catch and effort were obtained from creel census survey...
The mechanisms of mortality during critical life stages of fish are not well-understood and, for many species, it is not clear if the mechanisms are similar for naturally and artificially propagated individuals. For Chinook salmon (Oncorhynchus tshawytscha), natural fish potentially face negative interactions, such as competition, and survival disadvantages, such...
A critical seasonal event for anadromous Chinook salmon (Oncorhynchus tshawytscha) is the time at which adults migrate from the ocean to breed in freshwater. We investigated whether allelic variation at the circadian rhythm genes, OtsClock1a and OtsClock1b, underlies genetic control of migration timing among 42 populations in North America. We...
A study was undertaken in the fall of 1948 by the Oregon Fish Commission to determine the possible presence and importance of a delay in the migration of adult chinook salmon (Oncorhynchus tshawytscha) at Bonneville Dam on the Columbia River. Approximately 650 chinook were captured, tagged, and released at the...
An anemia of juvenile chinook salmon (Oncorhynchus tshawytscha) is described and stages of development separated by recognizable syndromes. A vitamin E-deficient diet of low rancidity produced a severe microcytic anemia with strong immature red cell response and granulocytosis occurring 2 to 4 weeks before a drop in hemoglobin and hematocrit...
The research involved development of two ecological
simulation models to explain the complex dimensionality of
chinook salmon (Oncorhynchus tshawytscha) life history
structure (represented by the age composition of the
spawning stock) and management difficulties entailed in the
complexity.
Since different sizes of chinook salmon are thought to
adapt differently to...
Hatcheries are used to produce salmon to augment the number of fish available for harvest, and to supplement wild populations that may be threatened with extinction. Although traditional hatchery rearing methods can produce many fish, they can pose risk to wild populations because they tend to produce salmon with lower...
4-nonylphenol (NP), a surfactant degradation product, is an unregulated, ubiquitous aquatic contaminant and endocrine disruptor, for which aquatic life criteria are currently under development by U.S. EPA. The effects of NP on estuarine amphipods and chinook salmon fry were investigated, and this dissertation reports research into the impacts of NP...
In a paper now in press as a Bulletin of the U. S. Fish and Wildlife Services the writer has discussed the downward trend of the catch of Columbia River Chinook salmon since 1920 and has stated that the decline is doubtless an indication that the runs of this species...
The genetic basis of adaptation is complex as many fitness-related traits are quantitative and likely influenced by multiple genes with variable effects across different selective environments. One important adaptation for anadromous Chinook salmon (Oncorhynchus tshawytscha) is the time at which individuals return to natal breeding sites within a reproductive season....