Mid-Hood Canal Juvenile Salmonid Evaluation: Duckabush 2008-2010 Hamma Hamma 2002-2010

Juvenile salmonid monitoring in central Hood Canal, Washington began in 2002 on the Hamma Hamma River and in 2008 on the Duckabush River. This work has been a collaborative project between the Washington Department of Fish and Wildlife (WDFW), Long Live the Kings (LLTK), and the Northwest Fisheries Science Centerfs (NWFSC) Manchester Research Station. This report describes the abundance, egg-to-migrant survival, and migration timing of chum, Chinook, and pink salmon juvenile migrants in each basin. These results are among the first published results of pink and chum egg-to-migrant survival for the Puget Sound region. Steelhead trout data from both systems are compiled and analyzed by the NWFSC Manchester Research Team as part of the Hood Canal Steelhead Project. Coho smolt catches have been too few to expand to an abundance estimate.

Duckabush River
Juvenile monitoring on the Duckabush River has been a cooperative effort between WDFW and LLTK since 2008. Results from LLTK trap operation in 2007 focused on the steelhead outmigration and are not included in this report. A floating five-foot screw trap is located at river mile 0.3 (0.48 rkm). In 2008 and 2009, the trap was operated from early February to the middle of June. In 2010, the trap was installed in the beginning of March and fished until the middle of May.

Juvenile production of Duckabush chum salmon ranged 4.7-fold during the 2008 and 2009 out-migration (Table 1). Egg-to-migrant survival for these years ranged between 3.0% and 17.1%. Chum estimates were a composite of summer and fall run stocks due to overlap in the out-migration timing. Genetic analyses will be needed in future years in order to partition the out-migration between the two parental stocks. Juvenile chum production was not estimated in 2010 due to a late start (early March) to the trapping season. Juvenile production of Duckabush odd-year pink salmon ranged between 17,750 (brood year 2009) and 35,788 (brood year 2007) with very low egg-to-migrant survival estimated for both years (0.93% for brood year 2007 and 0.93% for brood year 2009). Catches of Chinook salmon were too few to provide an abundance estimate.

Hamma Hamma River
Juvenile monitoring on the Hamma Hamma is led by LLTK staff and has been ongoing since 2002. Trap operations have changed over time. Between 2002 and 2007, a floating fivefoot screw trap was operated at river mile 0.5 (0.8 rkm) between mid January and late July. In 2008, the five-foot trap was swapped out for an eight-foot screw trap in order to increase catches of yearling migrants. During 2008 and 2009, the trap was operated from early February to the end of June. In 2010, the trap was installed in the beginning of March and fished through the end of May. Juvenile production was estimated for all years except 2003, 2006, and 2010 (Chinook and chum) and 2006 (pink) due to long trap outages in these years.

Juvenile production of Hamma Hamma Chinook salmon ranged 44-fold between 2002 and 2010 with an egg-to-migrant survival between 0.06% and 6.1% (Table 2). Juvenile production of Hamma Hamma chum salmon ranged 11.8-fold with an egg-to-migrant survival between 0.5% and 14.0%. Similar to the Duckabush results, Hamma Hamma chum estimates were a summer-fall composite and genetic analyses will be needed in future years to partition the out-migration into parental stocks. Juvenile production of Hamma Hamma odd-year pink salmon ranged 160-fold with egg-to-migrant survival between 0.08% and 0.5%.