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Management Applications of Chum Genetic Marking
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During
brood years 1990 through 1993 staff permanently changed
the allele frequencies at mIDHP-1 and mMEP-2 in chum salmon
from Tulalip Hatchery by intentional selection of spawners
with particular genotype. The presence of this genetic mark
in the population will facilitate the detection of straying
of hatchery-origin fish into natural spawning areas, improve
the ability of salmon managers in Puget Sound to estimate
the stock composition of mixed-stock fisheries, and potentially
enable managers in the Stillaguamish-Snohomish terminal
area to increase the harvest rate on hatchery-origin fish
and reduce the harvest rate on associated wild stocks. |
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The marked
Tulalip stock can also be used as an indicator for Puget
Sound origin chum salmon in large Canadian fisheries if
the production from the hatchery is increased, sample
sizes are increased, or other Puget Sound chum stocks
are genetically marked.
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Snohomish
River Chinook Salmon Straying Evaluation Study
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Beginning
with brood year 1993, all summer/fall Chinook salmon
from Tulalip Hatchery (operated by the Tulalip Tribes)
and Wallace River Hatchery (operated by the State
of Washington) have been mass-marked using thermal
variation of incubation water to place discernable
marks on the otoliths of developing embryos.
Beginning
with the 1996 field season we began collecting otoliths
from spawned out Chinook salmon carcasses throughout
the Snohomish River drainage. The results of laboratory
analysis of these samples have enabled us to estimate
the fraction of the naturally-spawning Chinook salmon
escapement in this river system that was derived from
hatchery-produced fish. Since the sampling design
is stratified based on the a priori expectation of
hatchery contribution for each region, we will be
able to compute an estimate of the straying using
standard equations of sampling theory. We are also
collecting samples from the returns to both hatchery
facilities to see whether naturally-produced fish
are returning to the hatchery facilities.
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Starting in 1997, we also began sampling terminal area
Chinook fisheries for otoliths. |
Funding
and Other Support for this Work
The current
field work, sample collection, and laboratory analysis
of samples is funded by the Tulalip Tribes and a grant
from the United States Department of the Interior to the
Tulalip Tribes via the Washington State Interagency Committee
for Outdoor Recreation. The genetic marking of the Tulalip
Hatchery chum has been funded by the Northwest Indian
Fisheries Commission using Pacific Salmon Treaty (PST)
implementation monies available through the United States
Department of the Interior. The otolith marking of Tulalip
Hatchery and Wallace River Hatchery Chinook has also been
funded with PST and NOAA Fisheries implementation funds
in the past. The Genetics laboratory and the Calcified
Tissue Analysis Laboratory at the Washington Department
of Fish and Wildlife are the contractors for sample analysis.
The Stillaguamish Tribe and the Washington Department
of Fish and Wildlife are assisting with field work and
sample collection.
For more information on this project call Tulalip Natural
Resources at:
(360) 651-4478, or write to 7515 Totem Beach Rd., Tulalip,
WA 98271.
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