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Develop conservation hatchery technology to aid recovery of ESA-listed stocks of Pacific salmon
Develop conservation hatchery technology to aid recovery of ESA-listed stocks of Pacific salmon
Problem Statement
Traditional salmon hatcheries may impact wild salmon populations. "Conservation hatcheries"
aimed at restoring such wild stocks to sustainable levels, must be developed.
Critical factors
- Hatcheries produce 70-80% of the salmon in coastal fisheries.
- Hatchery fish do not survive at rates as high as those of wild fish
and are often ill-equipped to survive in a natural environment.
- Hatchery practices and high rates of harvest in mixed-stock fisheries
that target hatchery fish have been identified as important factors contributing
to the decline of wild stocks.
- Scientists are looking at ways to modify conventional hatchery practices so
that hatchery fish can survive better in natural habitats.
- Accurate physiological, morphological, and behavioral measures of smolt
development in hatch ery and wild fish are needed.
- Agencies that operate traditional hatcheries have proposed developing "conservation
hatcheries" to rebuild wild stocks to self-sustaining levels, although the idea of
"conservation hatcheries" has not yet been widely accepted.
Status of research
The Northwest Fisheries Science Center's (NWFSC) Fisheries Enhancement
Program is working with other agencies on a Natural
Rearing Enhancement System (NATURES) in which scientists culture
Pacific salmon in raceways that simulate natural environments. Salmon in these
raceways grow accustomed to overhead cover, instream structure, substrate, and
non-intrusive feed delivery systems. The fish are also trained to avoid predators.
Scientists expect that this environment will produce salmon with characteristics
more like those of their wild counterparts and that these fish will show increased
rates of survival after release as compared to conventional hatchery fish.
The NATURES program is comparing fall chinook salmon raised in conventional
hatchery environments with fish raised in raceways with overhead cover, woody debris,
and bottom substrate. Initial studies indicate that when these fish were released
into streams, those raised in NATURES environments showed increased survival rates
of up to 20-50% as compared to the control group raised in a traditional aquaria
environment.
Scientists are also studying physiological, morphological, and
behavioral measures of juvenile salmon development. Experiments are being
conducted in which hatchery fish are grown in environments with water temperatures
and feed rations similar to those that wild fish encounter in order to synchronize
the growth cycles of hatchery fish with those of their wild counterparts.
Future considerations
Ongoing study should determine which hatchery modifications best prepare
fish to thrive in a natural environment. This knowledge can be used to help
develop "conservation hatcheries" and, if agencies continue to operate conventional
production hatcheries, to make those hatcheries more cost-effective. Improved
understanding of smoltification and development of low-cost methods for its
control inhatchery fish would allow management agencies to time releases to
coincide with, or avoid, critical events in the river or ocean environment.
Key Players
Resource Enhancement & Utilization Technologies (REUT) Division, NWFSC
Bonneville Power Administration
Washington Department of Fish and Wildlife
Oregon Department of Fish and Wildlife
California Department of Fish and Game
Idaho Department of Fish and Game
Northwest Power Planning Council
Long Live the Kings
Weyerhaeuser Company
Columbia Basin Fish and Wildlife Authority
Columbia River Inter-Tribal Fish Commission
National Biological Service, U.S. Geological Survey
Oregon State University
Pacific Fishery Management Council
U.S. Army Corps of Engineers
U.S. Canada-Treaty Commission
U.S. Fish and Wildlife Service
Contact: Dr. Walton Dickhoff, Director, REUT Division (206/860-3234)
NWFSC Issue Paper REUT 6201 (HQ ID 294)
Issue Papers Home
last modified 2002-07-30
Web site owner: Northwest Fisheries Science Center
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