Six Reasons to Protect Eelgrass

Unheralded marine plant shelters and feeds species while powering coastal ecosystems

Article June 7, 2019 Updated: February 7, 2023 By: Paul Shively Read time:

Projects: Conserving Marine Life in the United States

Eelgrass is one of the most important plants in the ocean. It cleans the water, nurtures fish, absorbs climate-warming carbon, produces oxygen, and protects the coastline—and that’s just for starters.

But this versatile seagrass, found in estuaries, bays, and other shallow nearshore areas, is disappearing because of pollution, dredging, development, sea level rise and other impacts. Approximately 30 percent of the world’s seagrass has vanished since the 1870s. Globally, we’re now losing an area of eelgrass that would cover two football fields every hour. On the West Coast, eelgrass in California’s Morro Bay has declined by more than 90 percent since 2007.

Here are six reasons to protect West Coast eelgrass:

1. Protects the coastline

Eelgrass beds provide natural buffers against coastal storms by absorbing the force from waves and, through their extensive root systems, preventing some shoreline sediments from washing away.

2. Mitigates climate change

Eelgrass absorbs carbon dioxide and methane—both climate-warming greenhouse gases—and stores them in its root system. By one scientific estimate, an acre of seagrass can sequester 740 pounds of carbon per year, about the same amount emitted by a car traveling 3,860 miles. Research suggests that eelgrass’s carbon sequestration also moderates the effects of ocean acidification, which can inhibit the ability of some marine life, such as oysters and Dungeness crab, to form shells.

3. Nurtures fish

Eelgrass beds play an integral role in the ocean food chain by providing habitat where microorganisms such as plankton thrive. The swaying grasses also offer shelter and foraging areas for rockfish, salmon, and Dungeness crab. Pacific herring, a vital forage fish, lay their eggs on the long, slender leaves of eelgrass. These are just some of the reasons NOAA Fisheries declared the plant essential fish habitat in 1996.

4. Feeds the Birds

Migratory waterfowl, including the Pacific black brant, eat eelgrass. In other regions, marine mammals rely on this and other seagrasses for nourishment.

5. Improves water quality and clarity

Like a massive filter, eelgrass helps improve water quality by absorbing pollutants. Recent studies show a drastic reduction in harmful chemicals such as polychlorinated biphenyls (PCBs) in areas with eelgrass beds. Other studies on the West Coast have shown that bacteria found in the beds help prevent harmful algal blooms. This flowering marine plant also traps and retains sediment, resulting in clearer, cleaner water.

6. Strengthens the coastal economy

Healthy beds support fish and shellfish that are integral to the commercial and recreational fishing industries—the economic engines of many coastal communities. Eelgrass also supports a wide array of wildlife that draws millions of visitors to the West Coast each year.

Paul Shively directs Pew’s efforts to protect ocean life and coastal habitats on the U.S. West Coast.