The typical coho salmon life history has been characterized by juvenile fish that spend their entire first year in freshwater habitats before migrating into estuaries as smolts. However, reports of early migrating coho fry (age 0), including migration downstream to estuarine habitats, date back to the 1960s. Until a few...
Parasites are unique study organisms for evolutionary ecologists. Yet, molecular ecology studies on parasites have lagged far behind those on free-living organisms. The goal of the review in Chapter 2 was to illustrate areas of research that may be of particular interest in relation to the parasitic life style and...
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 evolution and maintenance of multiple phenotypes within populations is an interesting evolutionary and ecological question, and is becoming increasingly important for the restoration and conservation of partially migratory species. In particular, why individuals adopt a particular phenotype has been the focus of numerous research efforts. In the partially migratory...
Greenland halibut (Reinhardtius hippoglossoides) have decreased in the eastern Bering Sea and Aleutian Islands since the 1970s. The reasons behind the poor recruitment are unknown, and important knowledge gaps of the ecology of the early life stages have been identified. The objectives of thesis research were (1) to examine geographic...
A Life Cycle Assessment (LCA) of the production of poplar biomass grown under four management conditions in the Pacific Northwest (PNW) of the U.S.A. was conducted. While the extraction of fossil fuels and the subsequent generation of energy have environmental impacts, the alternative of extracting poplar biomass also has impacts...
In this study, I examine the influence of habitat gradients created by the 1980 eruption of Mount St. Helens, Washington USA on a recently established Rainbow Trout (Oncorhynchus mykiss) population in the Spirit Lake basin. My goal was to evaluate the responses of fish in seven streams across a volcanic...
Ceratomyxa shasta is a myxozoan parasite that infects salmonid fishes causing the disease ceratomyxosis that is characterized by severe hemorrhage and necrosis of the intestine and death of the fish host. Ceratomyxa shasta is endemic to the Pacific Northwestern United States and Canada, where epizootics are reported for both wild...
My thesis explored the effects of environmental variability on population
dynamics and community composition of aquatic insects. Environmental variability in
the form of flow regime in streams can limit the distribution and life-history traits of
aquatic insects. I used tributaries to the McKenzie River in Oregon with dramatically
different flow...
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...