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Research about Oregon, Washington

Source-linked reports with geographic coverage including Oregon, Washington.

At least 253 records · Page 14Linked to original sources

Prolonged swimming performance of northern squawfish

We determined the prolonged swimming performance of two size-classes of northern squawfish Ptychocheilus oregonensis at 12 and 18°C. The percentage of fish fatigued was positively related to water velocity and best described by an exponential model. At 12°C, the velocity at which 50% of the fish fatigued (FV50) was estimated to be 2.91 fork lengths per second (FL/s; 100 cm/s) for medium-sized fish (30–39 cm) and 2.45 FL/s (104 cm/s) for large fish (40–49 cm). At 18°C, estimated FV50 was 3.12 FL/s (107 cm/s) for medium fish and 2.65 FL/s (112 cm/s) for large fish. Rate of change in percent fatigue was affected by fish size and water temperature. Large fish fatigued at a higher rate than medium-sized fish; all fish fatigued faster at 12 than at 18°C. The mean times to fatigue at velocities of 102–115 cm/s ranged from 14 to 28 min and were not affected by fish size or water temperature. Our results indicate that water velocities from 100 to 130 cm/s may exclude or reduce predation by northern squawfish around juvenile salmonid bypass outfalls at Columbia River dams, at least during certain times of the year. We recommend that construction or modification of juvenile salmonid bypass facilities place the outfall in an area of high water velocity and distant from eddies, submerged cover, and littoral areas.

Oregon, Washington↗

Environmental contaminants in bald eagles in the Columbia River Estuary

Eggs, blood, and carcasses of bald eagles ( Haliaeetus leucocephalus ) and fish were collected and breeding success of eagles was monitored in the Columbia River estuary, 1980-87, to determine if contaminants were having an effect on productivity. High levels of dichloro diphenyl dichloroethylene (DDE), polychlorinated biphenyls (PCB's), and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) were found in eggs, blood from adults, and 2 eagle carcasses. Detectable levels of DDE and PCB's were found in blood of nestlings indicating they were exposed to these contaminants early in life. Increasing concentrations of DDE and PCB's with age also indicated accumulation of these contaminants. Adult eagles also had higher levels of mercury (Hg) in blood than subadults or young indicating accumulation with age. The high levels of DDE and PCB's were associated with eggshell thinning (x̄ = 10%) and with productivity (x̄ = 0.56 young/occupied site) that was lower than that of healthy populations (i.e., ≥1.00 young/occupied site). DDE and PCB's had a deleterious effect on reproduction of bald eagles in the estuary. The role dioxins play in eagle reproduction remains unclear, but concentrations in eagle eggs were similar to those in laboratory studies on other species where dioxins adversely affected hatchability of eggs. Probable sources of these contaminants include dredged river sediments and hydroelectric dams, and the proper management of each may reduce the amount of contaminants released into the Columbia River estuary.

Oregon, Washington↗

Ages of rocks in southwestern Washington and northwestern Oregon as indicated by paleontological and isotopic dates

This report presents a compilation of 1,019 paleontologic dates and 301 isotopic dates of rocks in southwestern Washington and northwestern Oregon. The study area extends from Portland, Oregon (latitude 45°30' N.) to Bellevue, Washington (latitude 47°35' N.) and from the east flank of the Cascade Range (longitude 121°20' W.) to the coastline (longitude approximately 124°00' W.). The data are presented in two tables and come from previous summaries of isotopic ages, open-file reports, published papers and maps, and theses. Parke D. Snavely, Jr. of the U.S. Geological Survey and Weldon W. Rau of the Washington Division of Geology and Earth Resources (WDGER) generously allowed us access to files and records of more than 40 years of micropaleontological research in western Washington and Oregon. We also present unpublished data from our research since 1971 in northwestern Oregon. This compilation was undertaken for the southwestern Washington and northwestern Oregon project of the U.S. Geological Survey Evolution of Sedimentary Basins Program.

Oregon, Washington↗

Feeding of predaceous fishes on out-migrating juvenile-salmonids in John Day Reservoir, Columbia River

Diets of northern squawfish Ptychocheilus oregonensis , smallmouth bass Micropterus dolomieu , walleye Stizostedion vitreum , and channel catfish Ictalurus punctatus from John Day Reservoir were examined to determine the extent of predation on juvenile salmonids during seaward migrations of the salmonids during April–August 1983–1986. Juvenile Pacific salmon Oncorhynchus spp. and steelhead O. mykiss were the most important food group (by weight) of northern squawfish – about 67% – but made up smaller proportions of the food of the other predators: channel catfish, 33%; walleyes, 14%; smallmouth bass, 4%. Seasonal changes in diets indicated that northern squawfish preferred juvenile salmonids in May and August (generally the peak period of salmonid out-migration), and switched to prickly sculpin Cottus asper when numbers of juvenile salmonids declined; walleyes and smallmouth bass showed a preference only for prickly sculpin among the prey fishes analyzed. As judged by dietary composition and prey selectivity, the northern squawfish was the major fish predator on juvenile salmonids in the reservoir; channel catfish also were important predators in the upper reservoir in spring. Walleyes and smallmouth bass were much less important predators on salmonids, and appeared to select subyearling chinook salmon only in August when the distribution of this prey overlapped with that of the predators. Size-selective predation by northern squawfish may also play an important role in reducing survival of the smaller individuals within each run of out-migrating juvenile salmonids.

Oregon, Washington↗

Correlation of Miocene flows of the Columbia River Basalt Group from the central Columbia River Plateau to the coast of Oregon and Washington

Nearly twenty flows of the Columbia River Basalt Group (CRBG) can be paleomagnetically and chemically correlated westward as far as 500 km from the Columbia Plateau in Washington, through the Columbia Gorge, to the Coast Range of Oregon and Washington. In the Coast Range near Cathlamet, Washington, the CRBG flow stratigraphy includes 10 flows of Grande Ronde Basalt (1 low-MgO R 2 flow, 6 low-MgO N 2 flows, 3 high-MgO N 2 flows), 2 flows of Wanapum Basalt (both flows of Sand Hollow from the Frenchman Springs Member), and the Pomona Member of the Saddle Mountains Basalt. Elsewhere in the Coast Range, additional Grande Ronde Basalt flows, including flows of Winterwater or Umtanum, and additional Wanapum flows, including the flows of Ginkgo, have been reported. Thus at least 18 to 20 CRBG flows reached the coast region. Several of these distal flows have distinctive chemical and magnetic characteristics that are shared by nearby isolated intrusions in Coast Range sedimentary rocks, thus strongly supporting recent suggestions that these intrusions are invasive bodies fed by CRBG flows. Magnetization directions from several flows indicate 16 to 30° of clockwise rotation of the coast with respect to the plateau since middle Miocene time.

Oregon, Washington↗

Ground-water levels, spring 1985, and ground-water level changes, spring 1983 to spring 1985, in three basalt units underlying the Columbia Plateau, Washington and Oregon

Groundwater level contour maps for three basalt units of the Columbia Plateau regional aquifer system were constructed by using water levels measured in 1,105 wells during 1985. These measurements then were compared with similar measurements from spring 1983 to assess the changes in groundwater levels over the 2-year period for each of the basalt units. Configuration of the groundwater contours and water level changes reflect (1) recharge and discharge; (2) hydraulic conductivity; (3) use of imported surface water for irrigation; and (4) pumpage of groundwater. The movement of groundwater within each basalt unit is controlled mainly by the major rivers, streams, and coulees, whereas variations in flow directions between units are related to the occurrence, extent, and hydraulic conductivity of the basalt units and sedimentary interbeds and to differences in the amounts of recharge to each unit.

Oregon, Washington↗

Geometry of the Juan de Fuca plate beneath Washington and northern Oregon from seismicity

Earthquake hypocenters within the subducting Juan de Fuca plate beneath Washington and northern Oregon are interpreted as showing that the direction of plate dip changes from northeast beneath the Puget Sound region to east-southeast beneath southwestern Washington. The shallowest hypocenters within the Juan de Fuca plate are between 30- to 40-km depth, and the distribution of these events strikes north-northeast from near the mouth of the Columbia River to the northern Olympic Mountains. The distribution of hypocenters between 40 to 50 km generally strikes parallel with the shallowest events, but shows a significant broadening beneath the eastern Olympic Mountains and Puget Sound. Events with depths greater than 50 km south of the 1965 Seattle earthquake (mb = 6.5) strike north-northeast, approximately parallel with the shallower distributions; however, north of this event, the distribution of these deeper hypocenters strikes northwest. This change in the distribution of earthquake hypocenters reflects an upward arching of the Juan de Fuca plate plate beneath Puget Sound compared with the depth of the plate beneath southwestern Washington. The T axis calculated for the 1949 South Puget Sound earthquake (MS = 7.1) is oriented to the southeast, and the 20° plunge of the T axis is in good agreement with the plate dip angle determined from the earthquake hypocenters. We conclude that the 1949 earthquake resulted at least in part from down-dip tensional forces within the subducting Juan de Fuca plate. One consequence of the change in the direction of plate dip is that volcanic front in Washington is everywhere perpendicular to the dip of the Juan de Fuca plate.

Oregon, Washington↗

Effects of variation in flow on distribution of northern squawfish ( Ptychocheilus oregonensis ) below McNary Dam on the Columbia River

The movements of 23 northern Squawfish Ptychocheilus oregonensis were monitored by radiotelemetry below a Columbia River hydroelectric dam during the out-migration of juvenile anadromous salmonids in 1984 and 1985. The work was done as part of a study to relate predator abundances and distribution to juvenile salmonid mortalities associated with dams. Northern Squawfish remained in protected shoreline areas in spring and early summer, when discharge rates were high, but moved close to the dam and the juvenile bypass outflow area in mid to late summer, when discharge rates were low. Trends in northern Squawfish movements were similar during abrupt changes in discharge rate. During short-term closures of the spillway, when flow patterns were abruptly changed, four of five northern Squawfish moved out of protected areas and into the main river channel. Surface water velocities at 81 locations occupied by radio-tagged northern Squawfish in June to August 1985 ranged from 0 to 70 cm/s (mean, 24.5 cm/s). No preference within this range was evident, but the fish seemingly avoided areas of high current velocity, because they did not move into a substantial portion of the tailrace where water velocities exceeded 100 cm/s. Modification of structures to maintain high water velocities around bypass outflow areas should reduce potential predation on juvenile salmonids by northern squawfish.

Oregon, Washington↗