|
|
Juvenile salmon health
Juvenile salmon health
Problem Statement
Toxic chemicals in estuaries and nearshore environments may impair growth, suppress
immune response, and alter behavior in juvenile salmon.
Critical factors
- Estuaries provide crucial habitat for several species of juvenile salmon
during their migrations from rivers to the ocean.
- In the estuaries, juvenile salmon may encounter habitats that have been
physically altered by human economic development, chemical contamination,
unfamiliar predators, infections and pathogenic organisms, and unfavorable
ocean or climate conditions.
- These natural and human-caused environmental stresses can impair the
immune functioning of juvenile salmon, make them more susceptible to disease,
alter their behavior and neurological functioning, and impair their growth.
- Poor growth and increased susceptibility to disease can reduce the early
ocean survival rates of young fish.
- Exposure to commonly-used organophosphate pesticides may impair the
olfactory function of salmon, which could reduce their ability to avoid
predators or find their way back to spawning streams.
Status of research
State-of-the-art analytical and bioanalytical techniques are being used by
Northwest Fisheries Science Center (NWFSC) scientists to examine the ways
in which natural environmental variations and exposure to contaminants
affect juvenile salmon during their passage through estuaries in
Washington and Oregon. Studies focus on determining how natural and
human-induced stresses alter growth, affect neurological function and behavior,
and influence disease-caused mortality. Impacts on health which result from
exposure to toxic substances are also being examined and levels of exposure
to highly toxic compounds in juvenile salmon found in urban and non-urban
rivers and estuaries are being measured. Biological markers are used to
detect links between human-caused stresses and significant effects on fish health.
NWFSC scientists are also assessing the prevalence of key diseases in both natural
salmon populations and hatchery stocks and are studying the interaction
between altered immune function and disease susceptibility in juvenile salmon.
Future considerations
Juvenile chum salmon
|
Humans will continue to physically alter and chemically contaminate estuarine
and nearshore environments. In order to effectively manage those environments,
through habitat restoration and/or by reducing the flow of contaminants,
cause-and-effect relationships between threshold levels of toxic chemicals
and immune suppression, changes in neurological function and behavior, and
impaired growth in juvenile fish must be established.
Key Players
Environmental Conservation (EC) Division, NWFSC
U.S. Environmental Protection Agency
U.S. Army Corps of Engineers
Southwest Fisheries Science Center, NMFS
Natural resource agencies in Washington, Oregon, and California
|
Puget Sound Ambient Monitoring Program
Native American Tribal agencies
University of Washington
Oregon State University
Muckleshoot Indian Tribe
City and county environmental departments
Suquamish Indian Tribe
|
Contact: Dr. Tracy Collier, Director, EC Division (206/860-3312) 
NWFC Issue Paper EC 6505 (HQ ID 297/312)
Issue Papers Home
last modified 2002-07-29
Web site owner: Northwest Fisheries Science Center
|
|
