Spring Chinook Captive
Broodstock Program during 2007. Results should be considered preliminary
until published is a peer-reviewed journal.
The WDFW initiated a captive
broodstock program in 1997. The captive broodstock program collected
juvenile hatchery supplementation fish from five (1997-2001) brood
years (BY) with additional fish collected from the 2002 BY. The overall
goal of the Tucannon River captive broodstock program is for the short-term,
and eventually long-term, rebuilding of the Tucannon River spring
Chinook salmon population, with the hope that natural production will
sustain itself in the future. The project goal is to rear captive
salmon selected from the supplementation program to adults, spawn
them, rear their progeny, and release approximately 150,000 smolts
annually into the Tucannon River between 2003-2007. These smolts,
in combination with the current conventional hatchery supplementation
program and wild production, are expected to produce 600-700 returning
adult spring Chinook to the Tucannon River each year from 2005- 2010.
Seven captive brood progeny
adult returns were recovered during 2007. The number of captive brood
returns was expanded to 19 for the total run. Survival to adult returns
has been poor for this program to date.
Microsatellite DNA analysis
to date provides evidence that the captive broodstock program has
been an effective method of preserving overall genetic variation in
Tucannon River spring Chinook while providing additional smolts for
release.
During April 2008, WDFW
volitionally released 78,176 BY 2006 captive broodstock progeny smolts
from Curl Lake Acclimation Pond into the Tucannon River. These fish
were marked only with a CWT in order to differentiate them from the
supplementation fish (CWT/Left Blue VIE/No Finclip and CWT/Left Purple
VIE/No Finclip). One thousand captive brood progeny smolts were PIT
tagged to compare their outmigration with smolts from the supplementation
program. Monitoring their survival and adult returns, along with future
natural production levels, will be used to determine the success or
failure of this captive broodstock program. A final report, including
complete results of the genetics analysis, will be submitted by September
2009.
