Wild populations of fish are faced with a multitude of stressors, which may include human interaction, toxins, and disease. Benzo(a)pyrene (BaP), a known carcinogen and immunotoxin, has been reported in the stomach contents of juvenile chinook salmon, Oncorhynchus tshawytscha, in urban waterways. We investigated the impact of chronic dietary exposure...
Lahontan cutthroat trout (LCT) (Oncorhynchus clarki henshawi) are currently limited in their distribution to a patchwork of small isolated populations, the result of habitat degradation and natural variation in landscape and in-stream conditions. The objectives of this study were to determine how landscape level topographic features influence LCT distribution patterns....
Stress, including extreme or rapidly changing temperatures, are known to have deleterious effects on fish health and physiology. This thesis examines the combined effects of elevated acclimation temperature and acute handling stress on the number of antibody producing cells, plasma lysozyme concentrations, and the number of pronephric leukocytes in juvenile...
I used current water management practices in central and eastern Oregon and Washington as natural experiments to quantify the effects of irrigation water withdrawals on macroinvertebrate community structure and life history strategies. Reduced discharge had direct (e.g. decreased velocity and wetted habitat) and indirect (e.g. increased conductivity and temperature) effects...
Small low-head diversion dams are capable of removing much of the flow of a river, often resulting in increased water temperatures and habitat loss. Warmer temperatures have been shown to accelerate aquatic invertebrate growth and development, and discharge reductions can reduce instream habitat, suggesting that water withdrawals may alter both...
Co-management is considered an alternative approach to fisheries management,
however, not all co-managed fisheries have been successful. Most studies discussing the
success and failure of co-management have emphasized economic and social attributes of
success and failure, such as fishery rights and institutional arrangements. The effect on
co-management of biological characteristics,...
The objective of my study was to examine differences in riparian tree and shrub composition associated with adult aquatic emergence and implications for terrestrial spiders in these sites. Seasonal abundance and biomass of adult emergent aquatic insects, riparian arthropod abundances and spider densities were compared between conifer- and hardwood-dominated sites...
This thesis examined the influence of fall-spawning coho salmon on the density, growth rate, body condition, and survival to outmigration of juvenile coho salmon rearing in beaver ponds on the Copper River Delta, Alaska. During the fall of 1999 and 2000 fish rearing in ponds that received spawning salmon were...
The Pacific Northwest has a relatively low diversity of primary freshwater fishes with most of the endemism and diversity in the Columbia River and Klamath River. However, the Oregon Coastal Subprovince defined as the coastal rivers from Miami River in the north to Sixes River in the south, has a...
Salmonid run sizes are strongly affected by their early marine stage. Fully understanding the life history of salmonids means understanding how they interact with their marine environment and with other fishes. Changes in the biological and physical environment off the Columbia River region affects the distribution and abundance of predatory...