A solar-powered yellow buoy bobbing in the middle of Port Susan is collecting information that will help forecast migration conditions for Stillaguamish River chinook.

Funded in part by a GAP grant, the Stillaguamish Tribe’s Natural Resources Department deployed the buoy with the help of an Island Transporter barge in March 2011. A large concrete block was lowered into the water to anchor the buoy. Divers from the tribe’s Natural Resources Department surveyed the area to avoid impact to any eelgrass beds and ensured that the anchor was placed properly. The mooring system was recently upgraded to a helical anchor system that has a smaller footprint and can be adjusted with changes in sediment level.

The yellow buoy houses an oceanographic hydrolab that transmits real-time data about temperature, turbidity, salinity, chlorophyll and dissolved oxygen to the tribe, which uploads it to Northwest Association of Networked Ocean Observing Systems (NANOOS).

“We know these factors affect food resources in the estuary for out-migrating chinook smolts and migration conditions for returning adults,” said Don Klopfer, retired biologist for the tribe, who began the project four years ago.

Stillaguamish chinook are among the most threatened salmon populations in Puget Sound. When state and tribal co-managers plan fishing seasons, Stillaguamish chinook are one of the runs they strive to protect.

“One of our biggest challenges is determining how much harvest to allow without compromising the recovery of critical stocks,” said Shawn Yanity, Stillaguamish tribal chairman. “Information we learn from this buoy in Port Susan will be combined with existing Puget Sound and North Pacific oceanographic data to further improve our forecasting model.”

The buoy also helps document changes in estuarine conditions such as saltwater acidity, which can be a symptom of climate change, and monitor the effectiveness of marine habitat improvement projects.