Salish Sea Currents magazine

Environmental engineers and chemists at the University of Washington Tacoma have identified a mysterious compound implicated in the deaths of large numbers of coho salmon in Puget Sound. The chemical is linked with a rubber additive commonly used in tires and is thought to kill more than half of the spawning coho that enter the region's urban streams every year. 

Modern automobile tires are a complex mixture of chemicals, all used together in different ways to give tires their structure and properties, including riding comfort, safety and long life. Chemicals from tire wear particles are now thought to be responsible for the deaths of large numbers of coho salmon returning to spawn in Puget Sound streams. 

Many creeks and waterbodies in Puget Sound may look pristine, but most face serious threats from stormwater pollution. A new study at Soos Creek shows how mud-dwelling bugs, traditional chemistry and digital "heatmaps" can be used to track stormwater impacts and identify the most polluted areas. Scientists and planners hope that this may one day lower the price tag on costly stormwater fixes. 

Tiny bone samples show that seals alter their diets as conditions change. The findings could help scientists understand whether seals are contributing to local salmon declines.

Last month's federal authorization to kill more than 700 sea lions to protect salmon runs along the Columbia River is prompting discussions of similar actions for harbor seals in Puget Sound. But experts say the situations are very different with many unanswered questions. 

We have published a yearly round-up of stories from our magazine Salish Sea Currents. The 2020 edition focuses on the impact of climate change on the Salish Sea and includes a special section on the effect of global warming on infectious diseases in the ecosystem.