Annual rates of prespawn mortality (PSM) in adult Chinook salmon (Oncorhynchus tshawytscha) trapped and transported upstream of dams in the Willamette River basin are high (often >40%) and could limit the ability to restore natural populations of spring Chinook salmon if not reduced. Improvements at the U.S. Army Corps of...
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...
Marine heatwaves have become more common over the past several years. The 2014-2015 ‘warm blob’ had profound effects on marine ecosystems in the Northeast Pacific. Given the particular habitat needs of Chinook Salmon (Oncorhynchus tshawytscha) we wanted to examine the impacts of the heatwave on Chinook depth distribution. We examined...
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...
The Columbia River Basin historically supported abundant populations of Pacific salmon (Oncorhynchus spp.) but, largely due to anthropogenic influence, many populations are now listed as threatened or endangered under the U.S. Endangered Species Act. Habitat restoration efforts have been a critical component of salmon recovery plans. However, although the importance...
Anadromous salmonid populations in the Pacific Northwest have declined over the past 150 years. In 1999, wild spring Chinook salmon (Oncorhynchus tshawytscha) were federally listed as threatened within the Willamette Basin, OR. Currently, practices to restore wild populations in the upper Willamette Basin involve trapping wild adults at the base...
A study of the population ecology of Columbia River fall chinook
salmon, Oncorhynchus tshawytscha (Walbaum), was made in an attempt
to determine the cause of a serious decline in this run which occurred
in the early 1950's. Fluctuations in abundance of major salmon runs
the North Pacific were examined to...
Biochemical variation in 12 different chinook populations, sampled from 10 hatcheries along the Columbia River and the Oregon coast, was studied with starch gel electrophoresis. An index was
used to describe the genetic differences between pairs of populations. Differences were observed between spring and fall chinook and between Columbia River...
Juvenile fall chinook salmon were acclimated to full strength sea water at 66, 73, and 80 days after hatching. Survival in sea water for 14 days was used as the criterion for successful acclimation. The growth of salmon acclimated to sea water was slower over the period of observation (134...
