|
|
Estuarine and ocean ecology
Estuarine and ocean ecology
Problem Statement
There is little information available about the crucial period during which
juvenile salmon make their transition from salt to fresh water in estuarine
and nearshore environments.
Critical factors
- Over the past two decades, ocean conditions influenced by the California
Current have altered the biogeography of species (e.g., warm-water predators,
such as Pacific mackerel, have shifted northward), increased salinity in estuaries,
and decreased biological productivity.
- The critical transition from salt to fresh water is one of the least understood
life-history stages of Pacific salmon.
- The abundance of predators and the availability of forage fish to serve
as prey for larger fish, birds, and marine mammals help determine juvenile
salmon survival.
- Resource managers must understand the ecological linkages in estuarine
and nearshore environments and their influence on survival rates in order
to discriminate between natural population variations and the effects of
human activities.
Northern anchovy sampling off the Washington coast
|
Status of research
Northwest Fisheries Science Center (NWFSC) scientists are sampling juvenile
Pacific salmon in, and adjacent to, the Columbia River plume to determine
their health and growth rates. The scientists are also sampling to determine
the physical characteristics of the marine waters, the abundance and diversity
of prey and predator resources, and the biodiversity of the biological
communities in the nearshore ocean environment. NWFSC scientists are part
of a team that is preparing to sample the
waters around Oregon's Cape Blanco in June and August. At this location, the
California Current moves offshore, forcing the development of different
oceanographic environments north and south of the cape. The scientific
team will assess the physical and biological conditions of the marine environments,
and the impact of the current's shift on the distribution, growth, and survival
of juvenile salmon.
Future considerations
NWFSC scientists will test hypotheses to gain a better understanding of the
interactions among biotic factors (e.g., prey availability, predation, disease,
growth rates) and abiotic factors (e.g., river plumes, upwelling) that affect
juvenile salmon survival in estuaries and after their entry into the ocean.
A physical/biological model of the California Current that captures the
dynamics of regional circulation patterns and biological production must
be developed. Synthetic research on regional oceanography and the estuarine
and nearshore ecology of juvenile salmon must also be expanded. This will
make fishery forecast models more accurate and improve the ability to
manage harvests.
Key Players
Fish Ecology (FE) Division, NWFSC
Pacific Fishery Management Council
U.S. Army Corps of Engineers
Bonneville Power Administration
Northwest Power Planning Council
National Biological Service, U.S. Geological Survey
|
U.S. Fish & Wildlife Service
Columbia River Inter-Tribal Fish Commission
University of Washington
Oregon State University
Oregon Graduate Institute
|
Contact: John Ferguson, Director, FE Division (206/860-3270) 
NWFSC Issue Paper FE 6301 (HQ ID 310)
Issue Papers Home
last modified 2002-07-29
Web site owner: Northwest Fisheries Science Center
|
|
