To better understand how the health of Skagit Bay shifts over time and how changes correlate with the health of treaty resources, the Swinomish Indian Tribal Community is for the first time gathering its own cache of continuous oceanographic data.
The tribe’s Fisheries Department in mid-2023 deployed a buoy in the bay equipped with research instruments that automatically record water temperature, salinity, dissolved oxygen and chlorophyll content of the water every 15 minutes at about 1 meter below the surface.
“It’s establishing a baseline,” said Dan Sulak, environmental monitoring biologist for the Fisheries Department. “These kinds of data haven’t been collected in this area before, so we are starting to keep this record.”
Tracking these types of data is increasingly important as records around the globe show that climate change is influencing air and water temperatures, the carbon content of the ocean and more.
Shellfish species important to the Swinomish Tribe have been impacted by these changes, with heat waves cooking them on the shores and ocean acidification weakening their shells.
Most recently, a hot spell in July killed cockles left vulnerable during low tide. That mortality event was discovered during an eelgrass survey the tribe was conducting on reservation beaches.
“We’ve been collecting a lot of species and biological data for a long time, but this is a first for oceanographic data,” Sulak said of the buoy.
The tribe’s effort is filling a gap left by other research networks as well. Despite the Skagit River’s hugely important influence on the marine environment, the closest buoys operated by government agencies are in Padilla Bay and Penn Cove.
“This area is a unique environment. It is heavily influenced by the Skagit River, which is responsible for 30-60% of the freshwater entering Puget Sound, and ocean water in the region gets well-mixed from top to bottom as it flows in through the narrow and relatively shallow Deception Pass,” Sulak said.
The tribe’s hope is that over time, the buoy quietly archiving data in the bay may serve as a warning beacon—as thresholds too hot, too acidic, or otherwise harmful to fish and shellfish are reached—and fisheries management tool.
“Eventually we can tie this data into what’s happening with the biological data—the animals that are out there—and then tie that into the management of fisheries for those species,” Sulak said.
The reproduction, development and growth of shellfish including Dungeness crab and Olympia oysters, for example, are influenced by water temperature. Oxygen levels are also impactful and can affect the behavior of salmon.
“As this dataset continues to grow, the information will cultivate a better understanding of fisheries in this region,” said Tandy Wilbur, the tribe’s fisheries manager. “This includes possibilities such as better forecasting local salmon returns and predicting when stressful environmental thresholds will occur for shellfish.”
For now, Sulak visits the buoy monthly to clean the instruments and download the data. During the outing, he also manually collects data from surface to seafloor at a series of stops.
Those sites range from about 20 feet deep near the Swinomish Shellfish Co. farm to about 300 feet, and include a site roughly triangulated from where the north and south forks of the Skagit River funnel into the bay.
Fisheries Department staff plan to soon analyze the first year and a half of data and produce a report in 2025. They also envision making the data more readily available to the public.
“We plan to get the data available online soon in real time so anybody can look at it when they want to; our fishers here will be able to look at it, as well as anyone who is interested in the science,” Sulak said.
Above: Dan Sulak, environmental monitoring biologist for the Swinomish Fisheries Department, downloads data from research instruments tethered to a buoy in Skagit Bay. Photos and story by Kimberly Cauvel.
