Chum and Pink Workshop
Title: Spawn Timing, Outmigration Timing and Egg to Migrant Survival of sympatric Summer and Fall
chum salmon in the Duckabush River
Presenter: Josh Weinheimer
Authors: Josh Weinheimer – Washington Department of Fish and Wildlife, 360-902-2659,
Joshua.weinheimer@dfw.wa.gov
Joseph Anderson Washington Department of Fish and Wildlife, joseph.anderson@dfw.wa.gov
Maureen Small – Washington Department of Fish and Wildlife, Maureen.small@dfw.wa.gov
Mark Downen – Washington Department of Fish and Wildlife, mark.downen@dfw.wa.gov
The listing of Hood Canal summer chum (Oncorhynchus Keta) in 1999 resulted in a region wide effort to
reduce harvest, supplement weak or extirpated populations and restore freshwater habitat. To help
measure the success of these recovery actions, freshwater monitoring of adult abundance and juvenile
production was started in 2011 on the Duckabush River. The Duckabush is home to both summer and
fall chum populations, and both stocks tend to spawn in similar locations within the watershed. Summer
and fall chum have separate, distinct adult migration and spawn timing but there is great overlap in the
timing of juvenile outmigration between the two populations. We collected tissue samples from chum
fry to identify the proportion of summer vs fall chum throughout the entire juvenile outmigration via
molecular genetics. In addition, we estimate egg to migrant survival for both summer and fall chum.
Summer chum juvenile abundance was 6 to 27 times larger than fall chum across all years. Egg to
migrant survival ranged between 5% and 17% for summers and 1% to 8% for falls. Summer chum appear
to be more abundant at both life stages and survive at a higher rate than falls. Additional years of
monitoring will be used to further our understanding of life-history diversity and survival, including the
influence of juvenile migration timing on marine survival.
Presentation Type: Oral Presentation