The mission of the Stock Assessment division is to provide technical services for the monitoring and evaluation of biological populations - with an emphasis on salmonids in the Nooksack watershed. We focus on conducting annual stock assessments, surveys, and research projects.

This division takes a lead role in estimating annual productivity of Nooksack salmonid populations. While the life cycles of salmonids are complex, we focus on key stages of development including juvenile outmigration, marine survival, and adult spawning. By comparing trends in the number of juveniles produced to the number of adults returning, we can improve our understanding of how in-river conditions, ocean conditions, or both, are contributing to the health of our populations. Some projects are conducted annually to support fisheries management goals and include:

1. Operate rotary screw traps to monitor juvenile outmigration – We currently operate 2 rotary screw traps (Nooksack River near Ferndale, WA and South Fork Nooksack River near Acme, WA) to monitor the annual outmigration of salmonids. These data are used to inform metrics of spawning success from previous years as well as forecast future run sizes of returning adults.

2. Beach seining from the nearshore marine and estuary delta to the upper river watershed – We conduct beach seining across various key habitats to support evaluating annual outmigration, distribution, and densities of salmonids (and other aquatic species).

3. Conduct spawning ground surveys for adult salmonids – We coordinate with the Nooksack co-managers (Nooksack Indian Tribe and Washington Department of Fish & Wildlife) to conduct comprehensive adult salmon spawning ground surveys across the Nooksack watershed. These data are used to estimate and evaluate trends in total run sizes used in fisheries management planning and coordination.

Some examples of other research projects include:

4. Zooplankton sampling and monitoring in coordination with the Marine Survival Project (www.marinesurvivalproject.com) – Nearshore prey availability is important for outmigrating juvenile salmonids – this cooperative research program investigates the status and trends of zooplankton density and abundance across the Puget Sound. We conduct sampling near Portage Bay, which is representative of the North Puget Sound.

5. Utilizing light traps to monitor Cherry Point herring and Dungeness crab – In coordination with the Washington Department of Natural Resources, we are using light traps in Birch Bay, WA to evaluate density, timing, and transport of larval and juvenile Cherry Point herring as well as Dungeness crab.

6. Tracking upriver migration patterns of chinook salmon using radio tags – In 2019 and 2020, we tagged a total of 141 adult chinook salmon and tracked their migration to the spawning grounds using a combination of in-river tracking as well as weekly aerial flights over the Nooksack River.