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...
Dramatic changes in the physical and biological conditions off Washington and Oregon, USA, have occurred since 1998, including extreme El Niño (warm) and La Niña (cool) years, high and low Columbia River flow years, a major intrusion of subarctic water, and a low oxygen event on the shelf. The occurrence...
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...
During the summer of 1994, 1996, and 1997, we conducted hydrographic and plankton surveys of the upper 70 m in the nearshore, the continental shelf, and off shelf oceanic waters off Oregon, USA. Copepod densities and biomass were estimated along 4 transects from each cruise. The on shelf copepod biomass...
Predation by piscivorous marine fishes has been hypothesized to be a primary source of marine
mortality for Pacific Northwest juvenile salmon. During the springs and summers of 1998–2004, we collected predator and prey fishes (forage and juvenile salmonids) at the surface at night off the mouth of the Columbia River....
Well-defined fronts develop at the seaward edge of riverine plumes where suspended materials and planktonic organisms are concentrated by convergent water flows. Riverine plume fronts have been hypothesized to be favorable fish habitats because they can lead to localized prey
aggregations. We examined the spatial distribution of juvenile Pacific salmonids...