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Broodstock technology needed to restore depleted Pacific salmon stocks
Broodstock technology needed to restore depleted Pacific salmon stocks
Problem Statement
Captive rearing is one of the most promising means by which to preserve and restore
some depleted wild salmon stocks, but research is needed to minimize loss of
captive-reared fish from disease, low adult reproductive rates, and poor offspring
viability, as well as avoid harm to wild populations. The contribution of
captively-reared salmon to increases in population abundance also requires
additional study. Without captive rearing, critically endangered stocks such as
Redfish Lake sockeye salmon will become extinct.
Critical Factors
- Efficient, standardized techniques for rearing Pacific salmon in captivity
require further development.
- The importance of captive broodstock technology increases as more fish
are listed or proposed for listing under the Endangered Species Act.
- Gene pools of Snake River salmon must be maintained to ensure species survival.
Status of Research
The Northwest Fisheries Science Center (NWFSC) has begun a long-term, interdisciplinary
research program designed to improve captive broodstock rearing techniques and gauge
the potential of hatchery salmon to alter the genetics of wild populations. Center
scientists are studying a wide range of problems with respect to captively-reared fish,
including poor health, low survival rates, poor egg quality, and abnormal timing of
sexual maturity.
New vaccines are being tested for their effectiveness in combating
one of the major mortality agents in captively-reared salmon, bacterial kidney disease
(BKD). Researchers are testing new diets and feeding regimes in attempts to reduce
the incidence of asynchronous sexual maturation between males and females. Research
is alsoaimed at improving the spawning success of salmon reared full-term to adulthood,
through a combination of endocrine (hormone) and environmental (exercise) manipulations.
These studies directly support captive-rearing projects on the two Columbia Basin
fish stocks for which captive broodstock programs are critically needed: Snake
River sockeye and Snake River spring/summer chinook.
Currently, prespawning adults,
eyed eggs, and juveniles from captive boodstocks for listed Snake River sockeye
native to Redfish Lake and spring/summer chinook salmon from the Grand Ronde and
Salmon River are being returned to Idaho and Oregon to aid recovery. Adult returns
from these releases are showing signs that the Center's research efforts are ensuring
survival.
Future Considerations
NWFSC scientists will evaluate the reintroduction success of captively-reared
salmon in an attempt to improve chances of restoring wild runs, with minimal
impact on wild salmon. A technical manual to be used by other captive broodstock
programs wishing to restore wild salmon stocks will be compiled.
Programs for the most critically endangered stocks must be sustained over the
long term to prevent extinction.
Key Players
Resource Enhancement and Utilization Technology (REUT) Division, NWFSC
Bonneville Power Administration
Columbia Basin Fish and Wildlife Authority
Columbia River Inter-Tribal Fish Commission
National Biological Service, U.S. Geological Survey
Northwest Power Planning Council
Pacific Fishery Management Council
University of Washington School of Fisheries
U.S. Army Corps of Engineers
U.S. Fish and Wildlife Service
University of Idaho
Long Live the Kings
NWFSC Manchester Field Station, Manchester, WA
Biological Review Team, NMFS
Stanley Basin Sockeye Technical Oversight Committee
Snake River Chinook Propagation Technical Oversight Committee
California Department of Fish and Game
Idaho Department of Fish and Game
Oregon Department of Fish and Wildlife
Pacific Northwest Fish Health Protection Committee
Washington Department of Fish and Wildlife
Shoshone-Bannock Tribes of Idaho
Nez Perce Tribes of Oregon and Idaho
Washington State University
Contact: Dr. Walton Dickhoff, Director, REUT Division (206/860-3234)
NWFSC Issue Paper REUT 6202 (HQ ID 290)
Issue Papers Home
last modified 2002-07-30
Web site owner: Northwest Fisheries Science Center
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