The decline of many Pacific salmon stocks has stimulated interest in the early life history and habitat requirements of juvenile salmon. Although estuarine habitat associations of juvenile salmon have been investigated in many coastal areas of the eastern Pacific Ocean, until recently, little was known about juvenile salmonid ecology within...
Redband trout density was examined in three forested streams in central
Oregon at two scales, pool channel unit and microhabitat. Two streams were in
roadless areas and one was in a "highly managed" watershed. At the larger
spatial scale, trout displayed a seasonal shift in habitat use from early to...
Anadromous coastal cutthroat trout Oncorhynchus clarkii clarkii may be highly dependent on estuaries, passing through them multiple times during their lifetime. However, few studies have investigated estuarine use by coastal cutthroat trout and it is often thought that estuaries serve primarily as migration corridors rather than rearing areas. We used...
The extent of biological invasions, their role on the feeding of
native fishes and their impact on community stability were
investigated in Alsea Bay and Yaquina Bay, two estuaries on the
central Oregon coast, USA. Most nonindigenous species (NIS)
introduced in these intermediately invaded estuaries are
considered byproducts of culturing...
Newly emerged steelhead fry (Oncorhynchus mvkiss) of hatchery and
wild origins were studied in laboratory stream channels and natural
streams. Objectives of the study were to determine if and how earlier
emerging hatchery fry influence the emigration, realized densities,
growth, habitat use, social structure, and activity patterns of
localized populations...
Seasonal habitat availability, utilization, and selection by young
of the year (< 25 mm) and adult (>25 mm) redside shiner, Richardsonius
balteatus, were studied for 1 year in sections of Greasy Creek, Benton
County, Oregon. Intensive stream mapping procedures and snorkling
observations provided most of the quantitative measures for habitat...
Chinook salmon (Oncorhynchus tshawytscha) have been absent from their historic spawning and rearing grounds in the Metolius River Basin in central Oregon since 1968, when fish passage was terminated at the Pelton Round Butte Hydroelectric Project on the Deschutes River. Plans have been developed to reestablish passage of anadromous fish...
The overall goal of this study was to identify multiple scales of habitat use and habitat electivity by redband/steelhead trout and define the limiting factors affecting the distribution patterns of this species during summer flows.
The main objective in chapter 2 was to identify the most important habitat associations that...
Understanding seasonal changes in growth, survival, and movement rates is
crucial to salmonid management. These life history characteristics provide a context for
evaluation of management actions. We evaluated the life history of individually
marked Oncorhynchus mykiss gairdneri in the South Fork John Day River basin in
Northeastern Oregon. This thesis...
Reproduction of salmonid fishes in acidic water was studied
using the rainbow trout (Salmo gairdneri). Adult trout were exposed
to various levels of hydrogen ion (pH levels 4.5, 5.0, 5.5, and
control [6.5 to 7.1]) during the final 6 weeks of reproductive
maturation. Reduced survival rates of the progeny of...