Tucannon River Spring Chinook Salmon Captive Broodstock Program: 2007 Annual Report

This report summarizes the objectives, tasks, and accomplishments of the Tucannon River 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.