Publications

Formerly landlocked Coho Salmon (Oncorhynchus kisutch) juveniles (age 2) were monitored following release into the free-flowing Cowlitz River to determine if they remained in the river or resumed seaward migration. Juvenile Coho Salmon were tagged with a radio transmitter (30 fish) or Floy tag (1050 fish) and their behavior was monitored in the lower Cowlitz River. We found that 97% of the radio-t

Threats to marine and estuarine species operate over many spatial scales, from nutrient enrichment at the watershed/estuarine scale to invasive species and climate change at regional and global scales. To help address research questions across these scales, we provide here a standardized framework for a biogeographical information system containing queriable biological data that allows extraction

There is strong and growing interest in estimating the proportion of hatchery fish that are in a natural population (the hatchery fraction). In a sample of fish from the relevant population, some are observed to be marked, indicating their origin as hatchery fish. The observed proportion of marked fish is usually less than the actual hatchery fraction, since the observed proportion is determined b

Two high-head dams on the Elwha River in Washington State (USA) have changed the migratory patterns of resident and anadromous fish, limiting Pacific salmon to the lower 7.9 km of a river that historically supported large Pacific salmon runs. To document the effects of the dams prior to their removal, we measured carbon and nitrogen stable isotope ratios of primary producers, benthic macroinverteb

Viral hemorrhagic septicemia virus (VHSV) is a fish rhabdovirus that causes disease in a broad range of marine and freshwater hosts. The known geographic range includes the Northern Atlantic and Pacific Oceans, and recently it has invaded the Great Lakes region of North Ame­rica. The goal of this work was to characterize genetic diversity of Great Lakes VHSV isolates at the early stage of this vir

Parasites can regulate host abundance and influence the composition and structure of communities. However, host-parasite interactions might be context-specific if environmental conditions can alter the outcome of parasitism and disease. An understanding of how host-parasite interactions might change in different contexts will be useful for predicting and managing disease against a background of an

In October 2006, months after shallow experimental ponds in the Salton Sea Basin were filled with water from the Alamo River and Salton Sea, fish were observed in several ponds, although inlets had been screened to exclude fish. During October 2007–November 2009, nine surveys were conducted using baited minnow traps to document species and relative abundance of fish. Surveys yielded 3,620 fish rep

The relationship between virulence and overall within-host fitness of the fish rhabdovirus Infectious hematopoietic necrosis virus (IHNV) was empirically investigated in vivo for two virus isolates belonging to different IHNV genogroups that exhibit opposing host-specific virulence. U group isolates are more virulent in sockeye salmon and M group isolates are more virulent in rainbow trout. In bot

Viral haemorrhagic septicaemia virus, Genogroup IVa (VHSV), was highly infectious to Pacific herring, Clupea pallasii (Valenciennes), even at exposure doses occurring below the threshold of sensitivity for a standard viral plaque assay; however, further progression of the disease to a population‐level epizootic required viral amplification and effective fish‐to‐fish transmission. Among groups of h

We document the recent reappearance of anadromous sockeye salmon (Oncorhynchus nerka) that were thought to have been extirpated by the construction of hydroelectric dams on the Coquitlam and Alouette rivers in British Columbia, Canada, in 1914 and 1927, respectively. Unexpected downstream migrations of juveniles during experimental water releases into both rivers in 2005 and 2006 preceded upstream

Nucleospora salmonis is an intranuclear microsporidian that primarily infects lymphoblast cells and contributes to chronic lymphoblastosis and a leukemia-like condition in a range of salmonid species. The primary goal of this study was to evaluate the prevalence of N. salmonis in out-migrating juvenile hatchery and wild Chinook salmon Oncorhynchus tshawytscha and steelhead O. mykiss from the Snake

We used body morphology to distinguish between natural‐ and hatchery‐origin subyearling fall Chinook salmon Oncorhynchus tshawytscha in rearing areas of the Snake River and at a downstream dam during seaward migration. Using subjective eye and body shape characteristics, field personnel correctly classified 88.9–100% of natural subyearlings (N = 626) and 90.0–100% of hatchery subyearlings (N = 867