Bottom-up processes—including weather, water, and plankton—drive what is available for juvenile salmon and steelhead to eat. Bottom-up research activities fall into two categories:
- A Salish Sea-wide sampling program examines the condition of salmon and steelhead as they outmigrate while simultaneously evaluating the physical and biological (plankton) characteristics of the Salish Sea: the cornerstone of the marine ecosystem. This includes identifying critical growth periods for salmon and understanding the primary factors affecting growth during those periods.
- Individual bottom-up studies build off of this sampling framework: to hone our understanding of the relationship between salmon and their prey; and to build out from the fish and their prey to the factors driving prey availability, such as temperature, habitat availability, ocean acidification, runoff, and wastewater.
Sampling programs build out from specific watersheds within Puget Sound and the Strait of Georgia. In Puget Sound, it is the Nisqually, Snohomish, Skagit and Nooksack watersheds. In Canada, work was initially focused on the Cowichan watershed, and now studies have expanded to Big Qualicum River, Puntledge River and the Fraser River in addition to the Cowichan River. The U.S. is utilizing the capacity of their large co-management structure combined with academic and federal Principal Investigators to man the salmon and zooplankton sampling activities, and the existing buoy and water quality sampling network managed by the University of Washington and Department of Ecology to capture the physical properties of Puget Sound. The Canadians have implemented a community-based, citizen science sampling program, utilizing volunteers who will collect water quality and zooplankton data throughout the Strait of Georgia. The Canadians are also working with the academic and federal Principal Investigators for the sampling program and are utilizing them and others for salmon sampling.