Mussels do heavy lifting in spotting Puget Sound health trends
One evening in early November, while most are settling down after work, Washington Department of Fish and Wildlife (WDFW) staff and volunteers across Puget Sound are pulling on their boots and switching on their headlamps. This time of year, there are only a handful of days available to distribute mussels to nearly a hundred sites along the Sound’s shorelines, painstakingly timed with the season’s late-night low tides.
The ferry to Orcas Island rolls heavily in rough weather as two of us travel to our assigned site. With our Orcas-bound ferry already delayed by weather, the clock is ticking to catch the last ferry back to Anacortes.
Setting out for the winter
Preparations for this night began six months earlier with the evaluation of 41 potential survey sites as part of WDFW’s Mussel Watch program, and ramped up in October, when WDFW staff and volunteers bagged over 9,500 native bay mussels destined for the study. Over the course of five days in early November, more than 200 volunteers and staff installed 90 anti-predator cages containing these live mussels on beaches throughout Puget Sound, where they spent three months filter feeding through winter storms.
These volunteers and staff returned in January and February to retrieve the mussels and deliver them to WDFW’s laboratory in Olympia. There, they’ll be analyzed for chemical contaminants picked up during their time in the Sound, allowing researchers to determine the current status of contaminants present in nearshore ecosystems and how they’re changing over time.
Mussels support strong partnerships
Mussel Watch began as a nationwide monitoring program founded by the National Oceanic and Atmospheric Administration in 1986, and was adapted to a regional scale in 2012 by WDFW’s Toxics Biological Observation System (TBiOS) unit. Now largely focused on Puget Sound, this research program supports nearshore ecosystem health, recovery goals, public health, and regional management decisions.
This work is carried out through a long-standing network of partners:
· The Washington State Department of Ecology’s Stormwater Action Monitoring (SAM) program uses WDFW’s Mussel Watch data to evaluate the status and trends of nearshore contaminant conditions and to provide a regional assessment of whether collective stormwater management actions are leading to improved receiving water conditions.
· Penn Cove Shellfish supplies a clean aquaculture source of native bay mussels for the biennial surveys.
· Beyond these core collaborators, WDFW partners with federal, state, and local governments, tribes, nonprofit organizations, volunteer groups, and site sponsors across the region. These partners provide logistical support, volunteers, and local expertise, broadening the effort’s reach.
“Thank you to the landowners, property managers, and community members who support access to beaches and share their local knowledge. Your generosity and partnership make it possible for WDFW to do this work, and your support helps protect and better understand the places we all care about,” said Danielle Nordstrom, mussel monitoring field and lab coordinator.
Last spring, WDFW staff visited randomly selected locations along Puget Sound’s shoreline, evaluating these potential mussel monitoring sites to determine whether they met criteria including safe access and resilience to winter storms.
The scale of the WDFW mussel survey would be impossible without extensive volunteer and partner contributions.
During the mussel bagging effort alone, 25 volunteers from Sound Water Stewards joined WDFW staff for 25 hours of sorting, measuring, and preparing mussels for the study. Many community science volunteers, including Tim Manns and Brenda Cunningham, are Mussel Watch veterans, returning every study year to contribute their efforts.
“Brenda and I have long been concerned about the state of Puget Sound and the difficulty of keeping its water clean for all the Sound’s species with so much development and an ever-increasing human population,” said Manns. “Participating in Mussel Watch is one small thing we can do to help identify problem areas for the Sound’s water quality.”
The Penn Cove Shellfish aquaculture team also played a vital role in this process, making over 15 boat trips to the raft where these mussels were stored to rest after bagging, and then heading back out a week later to collect the mussels for cage deployment.
Over the week of deployment, 195 volunteers and partners braved wind, rain, ferry delays, and darkness to install mussel cages during late-night low tides, sometimes hauling gear along wooded trails and across muddy tidal flats to reach the intertidal site locations.
Once all the mussels have been retrieved from field sites, WDFW TBiOS staff and volunteers prepare mussel tissue samples for analysis at partner laboratories. Tissue samples from all sites will be tested for legacy organic contaminants (PAHs, PCBs, PBDEs, and organochlorine pesticides) and metals including arsenic, cadmium, copper, lead, mercury, and zinc.
Additionally, contaminants of emerging concern, namely pharmaceuticals, PFAS, and tire rubber compounds, will be tested at a subset of sites. These contaminants are of interest because they are widespread in the environment and can pose risks to human and/or wildlife health.
The results of these analyses will be summarized in a WDFW survey report made publicly available on WDFW and SAM websites, and included in the Mussel Watch story map. Findings will also be reported to the Puget Sound Partnership (PSP), a state agency focused on restoring ecosystem health in the Puget Sound. As part of the Toxics in Aquatic Life Vital Sign, mussel contaminant levels serve as an indicator of nearshore ecosystem health and help the PSP develop strategies to lower toxic contaminant levels and prevent additional contaminants from entering the Sound.
Final steps
Returning in late January to the San Juan Islands, we walk along a wooded trail at sunset to retrieve a mussel cage, grateful for the earlier low tides at this time of year. At each bend in the trail, we peer through the trees toward the beach, scanning for the cage that we left here three months ago. Though we did our best to anchor it in place, there are no guarantees that the cage stayed put through the winter storms.
Eventually, we spot it in the distance, feeling a mix of excitement and relief. The mussels have done their part in this research and are ready to be taken to the lab. Our fieldwork has been a series of shifting pieces, each clicking into place before the next phase begins. As mussel retrieval comes to a close, this logistical puzzle finally feels complete.
The Stormwater Action Monitoring status and trends report for the 2023–2024 Mussel Watch monitoring period contains detailed data on contaminant levels measured at Puget Sound nearshore sites and evaluates trends over time.
