This project was a collaboration between the City of Bellingham, the Skagit River System Cooperative (on behalf of the Sauk-Suiattle Indian Tribe and the Swinomish Indian Tribal Community) and the Lummi Nation to conduct an assessment of salmonid use of estuary and nearshore habitats. Project partners include NOAA (National Oceanic and Atmospheric Administration), the Bellingham Bay Action Team and the WRIA 1 Joint Board. The City received $125,000 for this project through the Washington State Department of Ecology via the Bellingham Bay Action Team, with the City providing $25,000 in match.
The study assessed salmonid use of the Nooksack estuary and Bellingham Bay nearshore habitats with an emphasis on juvenile Chinook salmon. The project examined juvenile Chinook salmon density dependence in the Nooksack estuary and the nearshore environment. Juvenile salmon growth is influenced by food availability, food quality, and water temperature among other factors. These factors also influence residence time within the estuary and along the nearshore and include, by extension, habitat capacity in those areas. Juvenile salmon out-migrating from the Nooksack River are also potentially using shoreline habitats of Bellingham Bay, and conditions within the Nooksack estuary may influence the timing and size of fish entering Bellingham Bay.
Data collected through previous studies by Lummi Natural Resources on juvenile salmon out-migrating from the lower Nooksack River, juvenile salmonids in the Nooksack estuary, and juvenile salmon in Bellingham Bay was used alongside data collected through this study to describe time-based, spatial, and habitat-use patterns of juvenile salmon in the estuary and nearshore environments. Native Nooksack Chinook, Bull Trout, and steelhead are listed as Threatened under the Endangered Species Act. Results from this study can inform long-term salmonid recovery efforts.
The primary outcomes of the study were:
1) Assessment of system-wide density dependence in the Nooksack estuary, factoring total habitat availability, habitat conditions, and connectivity.
2) Bioenergetics modeling (the study of energy transfer through a system) of habitat-specific growth potential, factoring prey inputs, diet, temperature, and local rearing densities of the Nooksack estuary.
3) Description of time-based, spatial, and habitat-type use patterns of juvenile salmon using the Bellingham Bay shoreline.
The project used beach seine sampling to monitor fish use in estuary and nearshore habitats, with an emphasis on juvenile Chinook salmon. Sampling occurred twice per month during the season when juvenile salmon were present within shoreline habitats of Bellingham Bay and the Nooksack estuary, February through October of 2014. Sampling was done by biologists from Skagit River Systems Cooperative with assistance from City of Bellingham sponsored Washington Conservation Corps (WCC) crews and technicians from Lummi Nation.
Data collected also included fish catch and length by species and hatchery mark, and data on the local environment such as temperature, salinity, dissolved oxygen, depth, and habitat type. In addition, prey samples were collected from the water column and from some Chinook stomachs in order to assess habitat conditions (see Example Field Sheet).
Research crews set a beach seine net during nearshore monitoring (left). A juvenile salmonid is measured during sampling (right).