Mussel Watch monitors toxics in Puget Sound

Mussel cage deployed at Oak Harbor at sunset

As fog swirled in over the Skagit River delta on a chilly autumn night, a team of community scientist volunteers finished securing a cage of mussels at the zero-tide line and began the long slosh back toward shore. Throughout Puget Sound, more than 100 other teams of Washington State Mussel Watch volunteers ventured onto the shoreline during the first week of November to place mussels for toxic contaminant monitoring.

Starting in late October, the volunteers sort thousands of mussels from Penn Cove Shellfish, cultured in a relatively clean (low contamination) area. The selected mussels are bagged, left to rest in their original offshore location, and then transported around the Sound to be placed in predator-proof cages that are then secured at the zero-tide line — an ideal zone for the mussels, and for monitoring toxics entering marine waters as well as contaminants already present in shoreline sediment.

The caged native bay mussels placed by the volunteers will remain at their designated locations through the rainy season, when stormwater flows into the Sound are greatest. In February, the cages will be retrieved and examined for toxic pollution through the Washington Department of Fish and Wildlife’s (WDFW) Mussel Watch program.

Toxic contaminants have impacts through the food web, affecting the health of Endangered Species Act-listed wildlife such as Puget Sound Chinook salmon and Southern Resident killer whales, and influencing our ability to depend on the Sound for sustenance and recreation.

Mussel Watch volunteers hail from organizations and communities throughout western Washington, representing a broad range of ages and backgrounds. They all share a desire to help preserve our unique ecosystem, and a sense of adventure.

“I have an interest in community science projects, particularly involving intertidal life,” said Tim Manns, who has volunteered every study year since 2012. “I’m not a scientist, but this is where I can contribute to getting good data that scientists can use.”

A group of volunteers poses with the mussel cage they finished deploying
WDFW’s Mariko Langness and volunteers place a mussel cage in the Skagit River delta

Every other winter season when the Mussel Watch program runs, “Volunteers transport mussels and equipment throughout Puget Sound, process samples in our Olympia laboratory, and document important data that is used to evaluate chemical contamination,” said Mariko Langness, Mussel Watch lead scientist with WDFW. “It’s a massive effort that wouldn’t be possible without the many volunteers and organizations we partner with.”

The Washington State Mussel Watch program began in 2012, when WDFW’s Toxics Biological Observation System (TBiOS) team began using transplanted mussels to monitor toxic contaminants in Puget Sound.

“Mussels are a useful indicator species for nearshore toxics because contaminants concentrate in their tissues and are retained for about three months,” Langness said. “Unlike more complex marine life such as fish, mussels lack a liver so they have a limited ability to break down contaminants.”

The mussels provide valuable data on a wide range of toxics present in their local environment, and how levels of contaminants may change over time. Toxic contaminants currently monitored include legacy chemicals — those banned years ago but persist in the environment for a long time — as well as emerging contaminants and heavy metals.

Two volunteers sort and inspect mussels
Sound Water Stewards volunteers sort mussels for bagging

The effects of legacy chemicals

Legacy chemicals are defined by their ability to resist breaking down in the environment, tendency to biomagnify (accumulate at higher concentrations up the food web), and having a high toxicity at very low concentrations. While many of the effects of legacy chemicals such as PCBs and PBDEs are well known, the health impacts of emerging chemicals such as PFAS, 6PPD-q, pharmaceutical products, and personal care products are still being studied.

Many toxic contaminants enter the environment through human activity. According to the Department of Ecology, surface water runoff, also called stormwater, is the most common source of toxic pollution entering Puget Sound, with wastewater being another pathway. Monitoring the nearshore (the area from the shoreline to a depth where sunlight cannot support marine vegetation) gives insight into the amount and types of toxics to which marine life and people may be exposed near specific locations.

Through the Mussel Watch program, a point-in-time toxics map can be created of the Sound, highlighting areas of greatest concern. This data is provided to other agencies and regulators to inform policy and help focus cleanup efforts. The State of the Sound report, published every other year by the Puget Sound Partnership, uses Mussel Watch data in the Toxics in Aquatic Life vital sign indicator. Data is also collected and provided to the Stormwater Action Monitoring collective and included in the national NOAA Mussel Watch Program.

The dozens of volunteers and partners who collectively contribute hundreds of hours, sometimes in adverse weather, make a project of this scale possible. In addition to our WDFW volunteers, volunteers from organizations such as Puget Soundkeeper Alliance, Sound Water Stewards, Port Townsend Marine Science Center, Feiro Marine Life Center, Bainbridge Beach Naturalists, Snohomish County Marine Resources Committee, and Harbor Wildwatch are instrumental in contributing to Mussel Watch.

Paul Belanger, president of longtime Mussel Watch partner Sound Water Stewards, said, “It’s contributing to the maintenance of the Salish Sea. When you get involved, you feel like you’re giving something back to this area.”



The Washington Department of Fish and Wildlife

The Washington Department of Fish and Wildlife is dedicated to preserving, protecting and perpetuating the state’s fish and wildlife resources.