Publications

Increased anthropogenic nutrient loading and the subsequent eutrophication of coastal ecosystems is a growing ecological and economic problem both in the United States and globally. Eutrophication can result in a range of ecological impacts including hypoxic conditions, fish kills, loss of submerged aquatic vegetation (SAV), degraded benthic conditions, harmful algal blooms, and...

Acoustic telemetry was used to obtain the movement histories of 915 juvenile fall-run Chinook salmon (Oncorhynchus tshawytscha) through the lower San Joaquin River and Sacramento-San Joaquin Delta, California, in 2008. Data were analyzed within a release-recapture framework to estimate survival, route distribution, and detection probabilities among three migration pathways through the...

Rainbow trout, Oncorhynchus mykiss, were infected with Ichthyophonus sp. and held at 10°C, 15°C and 20°C for 28 days to monitor mortality and disease progression. Infected fish demonstrated more rapid onset of disease, higher parasite load, more severe host tissue reaction and reduced mean‐day‐to‐death at higher temperature. In a second experiment, Ichthyophonus‐infected fish were reared...

We used capture-recapture data to assess population dynamics of endangered Lost River suckers (Deltistes luxatus) and shortnose suckers (Chasmistes brevirostris) in Upper Klamath Lake, Oregon. The Cormack-Jolly-Seber method was used to estimate apparent survival probabilities, and a temporal symmetry model was used to estimate annual seniority probabilities. Information theoretic...

No abstract available

In 2007, we used radio and acoustic telemetry to evaluate the migratory behavior, survival, mortality, and delay of subyearling fall Chinook salmon in the Clearwater River and Lower Granite Reservoir. Monthly releases of radio-tagged fish (~95/month) were made from May through October and releases of 122-149/month acoustic-tagged fish per month were made from August through October. We...

Invasive species have a substantial impact on natural resource management. The economic cost of invasive species to people in the United States is an estimated US$137 billion annually (Pimental et al. 2000). The environmental cost is much greater and usually incalculable (Pimental et al. 2005). Nearly half of the plant and animal species federally listed in the United States' Endangered...

This report presents the results for two sampling periods (October 2008 and January 2009) during a 4-year monitoring program to characterize selenium concentrations in selected irrigation drains flowing into the Salton Sea, California. Total selenium, selenium species (dissolved selenite, selenate, organoselenium), and total suspended solids were determined in water samples. Total...

Characterization of infectious haematopoietic necrosis virus (IHNV) field isolates from North America has established three main genogroups (U, M and L) that differ in host-specific virulence. In sockeye salmon, Oncorhynchus nerka, the U genogroup is highly virulent, whereas the M genogroup is nearly non-pathogenic. In this study, we sought to characterize the virus-host dynamics that...

n/a

We report results from ongoing research into the population dynamics of endangered Lost River and shortnose suckers in Clear Lake Reservoir, California. Results are included for sampling that occurred from fall 2006 to spring 2008. We summarize catches and passive integrated transponder tagging efforts from trammel net sampling in fall 2006 and fall 2007, and report on detections of...

The Nisqually Fall Chinook population is one of 27 stocks in the Puget Sound evolutionarily significant unit listed as threatened under the Federal Endangered Species Act (ESA). Preservation and extensive restoration of the Nisqually delta ecosystem is currently taking place to assist in recovery of the stock as juvenile Fall Chinook salmon are dependent upon the estuary. A pre...