In 2006–2007, an unusually high number of harbor porpoises (Phocoena phocoena) stranded along the Washington and Oregon coastlines. Spatiotemporal analyses were used to examine their ability to detect clusters of porpoise strandings during an unusual mortality event (UME) in the Pacific Northwest using stranding location data. Strandings were evaluated as...
The state of the California Current system (CCS) since spring 2010 has evolved in response to the development of cooler La Nina following the dissipation of the relatively weak and short-lived El Nino event of 2009-2010. The 2009-2010 El Nino appears to have dissipated quite rapidly in early spring 2010,...
Passive acoustic monitoring is a valuable tool for observing the status of marine environments. Comparisons of underwater soundscapes over temporal and spatial scales can provide data to inform marine conservation efforts, including protection of threatened and endangered species. This dissertation utilizes passive acoustic data collected via a broadly spaced array...
The state of the California Current System (CCS)
since spring 2011 has evolved in response to dissipation
of La Niña through spring and summer, resurgence of
cooler La Niña conditions in fall and winter, and finally
a transition towards ENSO-neutral conditions in spring
2012. The resurgence of La Niña was...
We combine high-resolution bathymetry acquired using the Autonomous Underwater Vehicle ABE with digital seafloor imagery collected using the remotely operated vehicle ROPOS across the axial valley of the Southern Explorer Ridge (SER) to infer the recent volcanic and tectonic processes. The SER is an intermediate spreading ridge located in the...
Climatic effects in the ocean at the community level are poorly described, yet accurate predictions about ecosystem responses to changing environmental conditions rely on understanding biotic responses in a food-web context to support knowledge about direct biotic responses to the physical environment. Here we conduct time-series analyses with multivariate autoregressive...
Diets of juvenile coho Oncorhynchus kisutch and Chinook O. tshawytscha salmon
are made up primarily of winter-spawning fish taxa in the late-larval and early juvenile stages that
are undersampled in plankton and larger trawl nets. Although we have no direct measure of the
availability of fish prey important to juvenile...
Upwelling in eastern boundary current systems is a primary driver of ecosystem productivity. Typically, peak upwelling occurs during spring and summer, but winter upwelling may also be important to ecosystem functions. In this study, we investigated the hypothesis that winter and spring/summer upwelling, operating through indirect trophic interactions, are important...
Coastal Pacific hake (Merluccius productus) are known
to spawn in the southern California Bight from January
to March, migrate north during late spring and summer
to feed off Oregon, Washington, and British Columbia,
and then move back to southern California in the fall.
Juvenile Pacific hake nursery areas have been...
A trophic model that simulates interactions between
a predatory fish (Pacific hake, Merluccius productus), forage
fish, and juvenile salmon off the Columbia River
was constructed to identify if trophic interactions could
account for marine mortality of Columbia River juvenile
salmon. The model estimates the number of juvenile
salmon that are...