Eelgrass research is an important part of the ecological work done at FHL, as reported in various previous Tide Bites (e.g., volumes 145, 125, 94) by scientists working on wasting disease, ecology, and restoration efforts.  This essay is the first Tide Bite in my memory written largely by an “outside” professional science writer.  Vishva came to FHL as part of a Northwest Science Writers Association group that visited last fall; she spoke with Mitch McCloskey while she was here and used that information to create the backbone and set the tone of this essay.  Mitch and Olivia Graham filled out some of the scientific details.  Great group effort, rather like the research itself!

Best,
Dr. Megan Dethier, FHL Director
Make your gift today

Seeding Hope in Declining Eelgrass Meadows

by Vishva Nalamalapu, Dr. Olivia Graham, and Mitch McCloskey

Vishva is a Seattle-based science writer. She completed MIT’s Graduate Program in Science Writing in 2023 and has predominantly worked in higher education communications, currently at UW Medicine. She loves learning about science, being in awe, and bringing readers into that experience through her writing. To read more of her work, please visit her professional website.

Eelgrass skirts the lengthy coastlines of the San Juan Islands where the waters are calm and protected.  Shallow eelgrass meadows surface when the tide lowers.  Deeper meadows have leaves up to three meters long.  “If you’re down in the meadow, you’re truly in it,” said Olivia Graham, postdoctoral research associate at Cornell University and UW Friday Harbor Laboratories.

Nudibranchs adorn the long eelgrass leaves, shimmering schools of fish weave through, jellyfish float by.  “They’re really vibrant, dynamic ecosystems that have so much life packed into them,” said Graham.

At Friday Harbor Laboratories (FHL), two projects are aiming to conserve and restore eelgrass, which can benefit the ecosystems and surrounding communities and help mitigate climate change.  Graham is helping to lead an EPA-funded research project studying stressors to local eelgrass meadows.  The San Juan Islands Conservation District (SJICD) has been working on an eelgrass restoration project led by Mitch McCloskey.  Sage Enright, eelgrass research assistant at the SJICD and a technician at FHL, is working on both.

The ecological function of eelgrass is significant. Eelgrass provides habitats for fish and oxygenates water, which animals need to survive.  It stabilizes shorelines and buffers them against waves from increasingly frequent and intense storms.  And eelgrass stores carbon in sediment, which prevents it from being released into the atmosphere.  It can do so even more efficiently than rainforests.

Eelgrass losses in the San Juan Islands have been severe in the last few years, especially in the shallow meadows.  Compared to the rest of the state, “We stand out for having dramatic eelgrass declines, and we don’t know why,” said Graham.

So, Graham’s team is trying to figure out why — what conditions are associated with eelgrass declines and with eelgrass resiliency.  They’re studying environmental factors like temperature, sediment factors like grain size, biological factors like fish communities, and seagrass wasting disease.  San Juan County is also taking aerial surveys to look at human stressors such as the number of anchored boats, which rip out eelgrass when their anchors are dropped in shallow waters.

The eelgrass stressor project began in July 2025 and will run for two years.  Each month, the research team visits six sites by boat to collect water samples to understand nutrient content, water chemistry, and how much light reaches the eelgrass. Each quarter, they dive for further observations.  And in July, they’re in the field nearly every day for a “big summer field season blitz.”

Field work is not only important for collecting data.  It also helps shift the eelgrass from an abstract concept to a tangible one.  “That very much helps keep the system alive,” Graham said.

The results are still in the works, but Graham isn’t expecting a single stressor to explain the declines.  “I think it’s multiple stressors rather than just one smoking gun,” she said.

Graham thinks that boat anchoring and warming temperatures may be the greatest stressors, particularly for shallow meadows which can be ripped out by anchors and exposed during low tides.  Warm temperatures also promote the protist pathogen that causes seagrass wasting disease, further endangering the eelgrass.

Understanding why eelgrass is declining is essential to preventing or minimizing further declines.  Restoration, however, can’t wait until then.  McCloskey is working with Graham and others to tailor seagrass restoration methods for the San Juan Islands.  “We don’t have this clear roadmap to what we’re doing, we’re trying to draw it as we go,” said McCloskey.  Eelgrass restoration work at Friday Harbor Labs was started by Dr. Sandy Wyllie-Echeverria, who spearheaded a seed-based eelgrass restoration effort, experimenting with techniques like buoy-deployed seeding and seed broadcasting.  While challenging, that work paved the way for the current initiatives.  McCloskey and Enright are working closely with Graham and other researchers to understand what factors are critical to eelgrass health.  Effective restoration relies on fundamental research; in this way, both projects go hand in hand to better understand and inform local eelgrass conservation and management.

The restoration team begins by wading, snorkeling, and diving to collect eelgrass flowers in healthy eelgrass meadows.  From June to September, Enright and McCloskey along with project partners, FHL students, and volunteers from the community enter the water to collect the branching eelgrass flowers that grow taller than the rest of the meadow.  Back at Friday Harbor Labs, they place the flowers in seawater tanks where they continue to develop until the mature seeds fall out and are caught by netting.  Enright sifts the seeds by first removing a mixture of decomposed plant material (“mush”) and seeds from the system and then passing this material through a series of progressively smaller sieves.  “This is when I tell myself that every seed counts,” they said.  The resulting mixture consists of flower fragments, seeds, and shell material, which is then slowly poured into seawater, allowing the denser seeds and shells to sink while lighter flower fragments remain suspended.  Enright then meticulously picks out individual seeds.  Finally, the team transfers the seeds into a cold storage unit until the spring planting season.

Last year, they injected seeds into the sediment at sites where eelgrass has disappeared, but this method was too labor-intensive to do at scale.  Furthermore, their plantings were largely unsuccessful.  Sea lettuce covered their plots, smothering the eelgrass seeds.  Eelgrass seeds are particularly fickle and require just the right conditions to germinate and grow into seedlings.  Enright’s recent winter observations confirmed a few seedlings at one of the restoration sites, providing a glimmer of hope.  These seedlings represent just a small proportion of all the seeds dispersed at the site, though, demonstrating the challenges of restoration.  “The thing is, restoration is hard,” said McCloskey.

Unfortunately, SJICD has made the tough decision to close down their eelgrass restoration program.  Between the challenging funding landscape and the fact that the stressors causing continued decline of the local meadows are still unknown, they were unable to keep the project on a trajectory for success.  However, the work they have done is valuable in furthering the knowledge base for eelgrass restoration in Puget Sound, and they will be sharing their findings with others.  McCloskey says, “Thankfully the eelgrass conservation and restoration community is strong, and we can feel good that we are handing our partners the baton to continue the push toward the return of our vibrant meadows.”

One experimental approach that is being handed off to other collaborators, especially the Puget Sound Restoration Fund, builds on growing evidence that bivalves can facilitate seagrass establishment by modifying sediment conditions.  Using native basket cockles as living planters, small groups of eelgrass seeds can be glued to cockles’ shells before the animals are placed back into suitable habitat.  As the cockles naturally burrow and move through the sediment, they transport seeds to depths favorable for germination while also oxygenating the seabed—processes known to alleviate chemical stress from sulfides in the sediment and thus improve seagrass performance.  This technique offers a hopeful and potentially scalable path forward for restoration efforts.

The difficulty of successfully planting eelgrass paired with the escalating environmental harms make eelgrass conservation and management in the San Juans timely but tenuous.  Yet the community of eelgrass restoration and conservation practitioners and researchers still find hope each day, in planting another seed, in watching it grow.

Tide Bites is a monthly email with the latest news and stories about Friday Harbor Labs.  Want more?  Subscribe to Tide Bites or browse the archives.