Hidden amongst Oregon’s estuaries lies a lesser-known but ecologically vital habitat: eelgrass meadows. These underwater grasslands thrive in the shallow estuaries and bays of the Pacific Northwest. Though often overlooked, eelgrass meadows play a critical role in maintaining the health of marine ecosystems, support biodiversity and combat climate change.
What is eelgrass?
Eelgrass is a type of seagrass that grows in the intertidal and subtidal zones of coastal waters. Unlike seaweed, eelgrass is a flowering plant with roots, stems, and leaves. It anchors itself in sandy or muddy substrates and forms dense underwater meadows that sway with the tides.
In Oregon, eelgrass meadows are commonly found in estuaries such as Coos Bay, Yaquina Bay, and Tillamook Bay. These areas provide the ideal mix of sunlight, nutrients, and shelter for eelgrass to flourish.
Ecological importance
Eelgrass meadows provide critical habitat for a wide range of marine species. Juvenile fish, including commercially important species like salmon, find refuge among the eelgrass blades. Shellfish such as Dungeness crabs and clams also rely on these meadows for shelter and food.
Beyond their role as a habitat, eelgrass meadows improve water quality by trapping sediments and absorbing excess nutrients, which helps prevent harmful algal blooms. Their dense root systems stabilize the seabed, reducing erosion and protecting coastlines from storm surges.
Climate change mitigation
Eelgrass meadows are powerful carbon sinks. They capture and store carbon dioxide from the atmosphere in their tissues and the sediment beneath them. Some research suggests that eelgrass meadows can sequester multiple times more carbon than terrestrial forests, making them valuable allies in Oregon’s fight against climate change.
Threats to eelgrass meadows
Despite their ecological significance, Oregon’s eelgrass meadows face numerous threats. Coastal development, pollution, and dredging disrupt their delicate ecosystems. Climate change poses additional challenges, including rising sea levels, ocean acidification, and warming waters, all of which can hinder eelgrass growth and survival, as well as the wildlife that live amongst it.
Invasive species, such as the European green crab, also pose a threat by disturbing the sediment and competing with native species that rely on eelgrass habitats. To date, Oregon has lost over half of its estuarine habitat, with eelgrass meadows in places like Coos Bay suffering reductions of over 80% in recent years.
Knowledge gaps
Despite all of these threats, we still don’t have a complete picture of how severely they’ve impacted Oregon’s eelgrass. For one, some portions of estuaries are in-part managed by state agencies such as the Oregon Department of Fish and Wildlife, the Department of Land Conservation and Development, the Department of State Lands, and the Department of Agriculture, to name a few. With so many agencies involved, collaboration can often be challenging, and that’s a problem when estimates suggest we’ve already lost over 50% of our estuarine habitat.
Additionally, many of our estuary management plans are decades old and eelgrass (found in estuaries) is highly sensitive to changes. Within that timeframe, eelgrass cover could change dramatically and as a result Oregon it’s difficult for us to have a cohesive understanding of eelgrass loss, and how best to address it.
Steps towards conservation
Estuarine health is declining and eelgrass is disappearing. This imperils the wildlife that rely on these areas, and also makes our coast less resilient to stressors. We need a higher-level understanding of what we’ve lost and more data on what we still have. To do that, Oregon needs more coordination between state agencies, more monitoring and more adaptive management to address the impacts of climate change, invasive species, pollution and development.
Fortunately, efforts to protect and restore eelgrass meadows in Oregon are gaining momentum. In the 2025 legislative session, there’s a bill with early bi-partisan support which would address these barriers and if passed, would set Oregon on a path towards healthier eelgrass meadows and estuaries.
Vital habitat worth protecting
Oregon’s eelgrass meadows are a testament to the intricate and interconnected nature of marine ecosystems. If we safeguard these underwater treasures, we not only protect the species that depend on them but also enhance the resilience of our coastlines and combat the impacts of climate change. It’s our responsibility to ensure that these vital habitats continue to thrive for generations to come.
Join us in calling on our legislators to take action.
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Authors
Ian works to protect our oceans and marine ecosystems. Ian lives in Portland, Oregon, where he enjoys ultrarunning, hiking, and local breweries in his free time.
