We examined the behavioral and physiological responses of wild
and hatchery-reared cutthroat trout Oncorhynchus clarki subjected to
a single electroshock, electroshock plus marking, and multiple
electroshocking in natural and artificial streams. In a natural
stream, trout released after capture by electrofishing and marking
showed distinct behavioral changes: fish immediately sought...
Juvenile chinook salmon (Oncorhynchus tshawytscha) were experimentally infected with Renibacterium salmoninarum (Rs), the causative agent of bacterial kidney disease (BKD), to investigate the effects of BKD on three aspects of juvenile salmonid performance: (1) predator avoidance ability; (2) smoltification; and (3) physiological responses to stress. For these experiments, fish with...
We describe the migration distances and timing of the adult Pacific lamprey, Entosphenus tridentatus, in the Willamette River Basin (Oregon, U.S.A.). We conducted aerial surveys to track radio-tagged fish upstream of a major waterfall and hydropower complex en route to spawning areas. We detected 24 out of the 43 fish...
This study examined the potentially stressful
effects of tagging juvenile rainbow trout Oncorhynchus mykiss
with passive integrated transponder (PIT) tags by measuring
short-term (<120-h) changes in plasma concentrations of
cortisol and hepatic heat shock protein 70 (hsp70). In a
laboratory experiment, plasma cortisol levels were measured
in fish before they...
In order to more effectively design large, complex systems, risk must be accounted for throughout the design process. A systematic way to account for risk is by using system model simulation. During the conceptual design phase, functional models can be drawn to help the engineer design their system's functional architecture....
Pleuropogon oregonus Chase is a rare wetland grass endemic to eastern Oregon. The species is composed of two widely separated populations, one in Lake County and one in Union County. In order to reduce the risk of extinction, the Oregon Department of Agriculture Native Plant Conservation Program initiated several reintroduction...
We studied the feasibility of using end-grain characteristics to match individual boards and cants back to their parent Douglas-fir (Pseudotsuga menziesii) logs. After reviewing marking/reading and biometric automated identification systems, we focused on end-grain biometrics because they appear to have the most promise for sawmills. Biometric identification requires that every...
Most recent research on stream amphibians in the Pacific Northwest has focused on associations with reach-level or stand-level environmental features. Little is known about landscape-level distributions of these species or landscape-level aspects of their life-histories. I used a watershed-wide sample and logistic regression to develop models and maps of probability...
Aim The hypothesis that habitat fragmentation negatively influences biodiversity stems from island biogeography and metapopulation theory which predict negative impacts of decreasing patch size on richness and distribution patterns. Empirical support of this idea is weak in terrestrial systems, though tests of fragmentation effects are typically confounded with landscape composition...
Social information is used widely in breeding habitat selection and provides an efficient means for individuals to select habitat, but the population-level consequences of this process are not well explored. At low population densities, efficiencies may be reduced because there are insufficient information providers to cue high-quality habitat. This constitutes...
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. Schmidt, J. Johansson, M. G. Betts, unpublished data) to maintain mean quality, which
may not be realistic