Protect the remaining seagrass meadows, one of the world’s most endangered and least understood ecosystems, critical for food security and carbon storage.
Seagrasses are undersea flowering plants that cover tens of thousands of square miles of coastal habitat worldwide, supporting hundreds of threatened or endangered animals. Manatees and sea turtles eat seagrasses, juvenile fish shelter in their meadows, and plant blades harbor tiny shellfish. Seagrass sediments sequester millions of metric tons of atmospheric carbon each year while protecting corals and shellfish from ocean acidification. Seagrasses support local fisheries, providing food security for millions of people, including many Indigenous communities. Nearly a third of historic seagrasses have disappeared and continue to decline by up to 7 percent per year. Less studied and protected than other ecosystems, seagrass meadows are difficult and expensive to restore. It is imperative to stop further damage and protect all remaining seagrasses.
Learn why seagrasses are valuable and why they are uniquely threatened. The nearly seventy species of seagrasses are ecosystem engineers that transform seafloor sediments into marine habitat and sequester carbon. These plants are extremely sensitive, with precise ecological requirements for water quality, light, temperature, and wave action, so they have been called “coastal canaries” that signal environmental degradation.
- Seagrass meadows occur from the tropics to the Arctic. Australia has the largest seagrass area of any country.
- Along with mangroves and tidal salt marshes, seagrass meadows are blue carbon ecosystems—coastal habitats that are extremely efficient carbon sinks. By drawing carbon into their roots and capturing sediment, seagrasses build soils that store 10–18 percent of all carbon buried in the seabed annually, as much as 19.9 billion metric tons (see Mangroves Nexus and Tidal Salt Marshes Nexus).
- In the tropics, many people may get a large part of their protein from fish that rely on seagrass meadows. Prawns, conch, and many other fisheries depend on seagrass. If you have eaten cod, you have benefited from seagrass, which is a favorite habitat for juvenile cod.
- Dugongs, marine mammals that are threatened with extinction, eat seagrass exclusively, while maintaining the health of seagrass meadows. Sea turtles, manatees, and sea horses all inhabit seagrass habitat. The only omnivorous shark, the bonnethead, eats seagrass.
- Seagrasses can spread via seeds that can float and colonize new sites, or through rhizomes (spreading roots) that stabilize sediments, protecting coastlines and water quality. Both seeds and rhizomes are used for restoration, and the seeds are an important food for the Seri people.
- The oldest known plant, at two hundred thousand years old, is a type of seagrass called Posidonia oceanica. It clones itself through a slowly growing cluster of roots and rhizomes that can store carbon for millennia.
- Seagrasses are one of the least protected coastal ecosystems. Only 26 percent of seagrass habitat falls within a Marine Protected Area.
- Seagrasses face a wide range of threats. The chief threat is fertilizer runoff, which causes eutrophication (damaging overabundance of algae). Another threat is sediment from erosion, which reduces light. They can be damaged by too much noise. Climate change imperils seagrasses through temperature change, greater storm intensity, and sea level rise.
- When stressors are removed, quick-growing seagrasses can be restored. However, slow-growing seagrasses such as Posidonia oceanica may be difficult or impossible to restore in the short term. Even in the best case, seagrass restoration is expensive compared to other ecosystems.
Help stop bottom trawling. Bottom trawling, an industrial fishing practice that uses large nets dragged along the sea bottom, uproots seagrass and is a major driver of their destruction around the world. It also catches noncommercial species, such as seahorses, that live in the seagrasses. Shrimp, crab, and flatfish are often bottom trawled (see Global Fishing Fleets Nexus).
- Avoid eating fish and shellfish that are bottom trawled. The Monterey Bay Aquarium’s Seafood Watch can help you identify bottom-trawled seafood and find seafood that is environmentally and socially responsible.
- Support organizations committed to stopping bottom trawling. Project Seahorse, Marine Conservation Institute, and organizations in the Transform Bottom Trawling coalition are all working to prevent this destructive practice.
Volunteer to research and/or restore seagrasses. Citizen scientists can make important contributions to understanding seagrass ecosystems, and seagrass-related citizen science is expanding. Volunteers are essential in many seagrass restoration programs.
- You can find initiatives that support your local seagrasses by searching on seagrasses and your region. Examples are New York State’s Got Seagrass survey, The Community Seagrass Initiative in southwest England, or a seagrass monitoring initiative for the Great Barrier Reef.
- SeagrassSpotter is a global research program in which anyone can use an app to upload pictures of seagrasses and map them.
- Seagrass-Watch needs highly trained and committed volunteers who partner with scientists to track seagrasses with a rigorous, standardized protocol that is used worldwide.
- Ocean Conservation Trust needs volunteers to pack seed bags in the UK.
- VIMS involves volunteers in collecting seeds for seagrass restoration in Virginia, and there are multiple volunteer opportunities in Florida.
- In Australia, volunteers gather seagrass shoots washed up by storms.
Raise awareness of seagrasses and the important role they play. A major obstacle to seagrass conservation is lack of awareness about this ecosystem.
- Write an op-ed on seagrass. This op-ed discusses how seagrass conservation saves manatees in Florida. This one urges readers in the UK to support a global oceans treaty to prevent bottom trawling. This op-ed argues for a campaign to protect seagrasses at resorts in the Maldives.
- Follow seagrass organizations or researchers on social media. Seagrass Restoration Network has links to a number of leading organizations (see Key Players).
- For educators, Teach Ocean Science has seagrass resources that meet U.S. National Science Education Standards. Seagrass-Watch provides videos and activity books.
- You can share pictures of seagrass from around the world.
- Speak up for marine animals such as dugongs, manatees, and seahorses that rely on seagrass meadows for food and habitat.
Landowners and Farmers
Manage runoff and erosion. Threats to seagrass can originate a thousand miles inland, including fertilizer runoff and sediment from erosion. Reducing or eliminating fertilizer use and improving soil health will protect seagrasses.
- The Regenerative Agriculture Nexus provides a suite of practices that can reduce costs and improve soil fertility while converting farmland from carbon source to carbon sink.
- Hedgerows (planted with trees, shrubs, and perennials), buffer zones, and prairie strips are inexpensive and effective ways to prevent runoff and provide additional benefits such as bird habitat, pollinator habitat, weed control, and erosion control.
Don’t bottom trawl or dredge fish. Bottom trawling destroys habitat underneath it, depleting the fishery and suspending sediments that worsen water quality and release stored carbon.
- Alternative methods can protect fisheries and produce better-quality fish.
- Trammel or gill nets, longlines, and traps are viable alternatives that also produce less bycatch for some fisheries.
Respect Marine Protected Areas (MPAs) and other restricted areas, and participate in their management plans where possible. MPAs can improve nearby fisheries by providing protected spawning grounds and increasing the size of fish around them, while keeping carbon sequestered in seagrasses.
- A study of multiple reserves showed that they made local fisheries more sustainable, with better catches close to the reserve.
- In Italy, fishers worked with MPA managers to create a successful comanagement plan.
- A no-take zone in the Philippines provided better catch for less effort, with increased income from fishing and tourism.
- See Marine Protected Areas Nexus for more information.
NGOs and Resource Managers
Prioritize protecting existing seagrass. Seagrasses are declining quickly so protecting remaining seagrass meadows is urgent. Restoration of seagrasses is a last resort. There is no guarantee that former seagrass habitat can again support seagrass when the ecosystem engineering they provide is lost.
- Map, monitor, and protect areas of seagrass that can provide propagule (seed and shoot) sources, diversity, and connectivity. This both maintains current seagrass meadows and makes it possible to restore or rehabilitate barren areas. Long-term monitoring can verify whether actions and policies are having the desired impact.
- Collaborate with local communities. Create improved outreach, stakeholder cooperation, and management, as in this New York example of a seagrass management coalition.
- Create boating restriction zones. Many counties in Florida have restricted powerboats from seagrass areas.
- Educate boaters and other users on how to protect seagrass. The Ocean Foundation has a boater education toolkit. Big Bend Seagrass Aquatic Preserve in Florida uses kiosks, brochures, signs, and event participation to educate and do outreach.
Use best practices when and if restoration is being attempted. Seagrass restoration is expensive and risky, but it is also necessary where feasible to counteract previous losses. Done with care, restoration is possible and can create speedy recovery, not only of seagrasses but also ecosystem services, as in this 9,000-acre project in Virginia’s Coastal Bays.
- Assess the site carefully and ensure that water quality, light, and wave energy are appropriate for seagrass survival.
- Remove threats to seagrasses. Simply improving water quality may be sufficient to allow seagrasses to reappear. However, other threats may also impede recovery.
- Plant on a large scale. Large plantings (at least a thousand seeds or shoots) have more survivors and better growth rate than smaller ones because they can spread out risks and enable positive feedback among survivors, such as wave buffering.
- Work on long timescales. The Virginia Coastal Bays project, one of the most successful restoration projects in the world, attributes its success in part to seeding and monitoring seagrass for over twenty years.
- Work with Indigenous people. Malgana Indigenous Rangers are part of successful seagrass restoration in Shark Bay (Gathaagudu), Australia. Māori have been active in seagrass monitoring and restoration in Whangarei Harbor.
Research seagrasses. Seagrasses are understudied compared to coral reefs and salt marshes. Research that supports conservation efforts and clarifies the interactions between seagrasses and climate change is badly needed. Research gaps include:
- Mapping, distribution, and baseline assessments of seagrass health. Large tracts of seagrasses have not been surveyed and may require innovative methods.
- A platform to facilitate sharing research on regional and global scales.
- Understanding carbon storage of seagrasses along with areas at risk for becoming carbon sources.
- Restoration and resilience needs of seagrass, such as habitat requirements for particular species and the role of connectivity.
- Seagrass physiology, genetic diversity, and role of fish nurseries.
Collaborate with Indigenous people. Holders of traditional ecological knowledge can assess ecosystems relative to their historical status, countering the problem of shifting baselines. They are proactively adapting to climate change. Collaboration should include aligning research with the goals of Indigenous people.
- In Zanzibar, Indigenous people provided extensive information on seagrass uses, ecosystem services, and local ecology, which can inform a management plan.
- Coastal Tamil-Nadu communities have a much more fine-grained understanding of local species and varieties than that provided by conventional species classification, including their preferred microhabitat and medicinal uses.
- The Seri people of the Gulf of California have detailed understanding of local Zostera marina reproductive cycles.
Raise awareness of seagrasses. One of the greatest barriers to seagrass protection is lack of understanding of even basic facts.
- A researcher of seagrass awareness recommended other researchers use social media posts as a means of education.
- Creating general-interest and nonspecialized publications and working with educators and communications specialists can also bridge the awareness gap.
Marine vessel owners, captains, and pilots
Be seagrass safe by boating responsibly. Propeller ruts, groundings, and improper moorings create scars in meadows that can last decades.
- Moor safely. Anchor away from seagrass, use an environmentally friendly mooring, or modify your mooring to keep the chain off the bottom.
- Under way, follow Avoid-Trim/Troll-Push procedures: Avoid shallow waters and stay in marked channels. Above seagrass, trim up your prop and troll or drift. If you run aground, get out and push your boat off to save seagrasses—and your propeller.
- Be informed. Know your draft, know the tides, and review charts. Polarized sunglasses can help you see seagrass.
- Take the Seagrass Safe Pledge if you’re a Florida boater.
Follow dredging protocols that preserve seagrasses. Dredging creates turbidity that prevents seagrasses from getting the light they need. Timing dredging to coincide with seagrasses’ dormant period improves their survival and regrowth, as does selecting sites where seagrasses are resilient. By assessing light requirements and monitoring light, a large dredging project successfully prevented seagrass loss. Low light, high frequency, and long dredging period all increase risk to seagrasses, but dredging regimes can be adjusted to meet the needs of ports and seagrasses.
Protect seagrasses around your resorts. Some resort owners consider seagrasses to be unsightly and remove them. However, besides protecting your beaches, seagrass meadows keep water clear and can provide amazing ecotourism adventures.
- In the Maldives, many resort owners are pledging to protect their seagrasses.
Remove bottom-trawled fish from your supply chain. Bottom trawling is the result of perverse incentives that lead to destroyed fisheries. It releases as much carbon as aviation.
- The Marine Stewardship Council can help locate certified-sustainable fish on their suppliers page. Searching by fishery allows you to set filters for sustainable methods such as longlines or gill nets.
Reduce pollution runoff through incentives, outreach, and technical assistance. Reducing nutrient and sediment runoff is critical for maintaining existing seagrass populations. Nutrient pollution threatens existing seagrass beds and can make restoration efforts unsuccessful.
- New Hampshire’s Great Bay, Boston Harbor in Massachusetts, and Tampa Bay, Florida, have all enabled dramatic comebacks of seagrass meadows by managing nitrogen pollution.
- New Zealand uses holistic management of coastal ecosystems and their catchments to manage water quality.
- In the United States, the EPA has a number of resources for reducing runoff.
- Australia has a joint management plan for managing runoff to the Great Barrier Reef Marine Protected Area.
- Seagrasses are important indicators for water quality. In Australia, if seagrass density drops below 25 percent of its historical average, action to decrease pollution is required.
End bottom trawling and other destructive fishing. Bottom trawlers are often fishing in foreign waters, depleting fisheries that small-scale fishers and Indigenous communities depend on. Bottom trawling ranks very high among fishing techniques in habitat destruction, bycatch, and fuel use.
- Prohibit bottom trawling in areas that can serve as refugia for seagrasses and other organisms, including inshore exclusion zones, MPAs, and currently untrawled areas. This can also improve conditions for small fishers. Coastal zoning can reduce damage to eelgrass beds while allowing fishing in less sensitive habitat; many countries prohibit fishing over seagrass entirely.
- End subsidies that create perverse incentives for overfishing. Subsidies for fuel, distant-water fishing (promoting high-seas fishing), and boat construction all encourage overexploiting fisheries, decrease food security, and stimulate greater fuel use.
- Implement secure fishing rights (catch share) programs to make it easier for fishers to adopt environmentally sound practices. Catch share programs that allocate a share of the total catch to participating fishers align fishers’ incentives with sustainable management. Environmental Defense Fund’s Sustainable Fisheries Toolkit maps out a process for developing a management plan with stakeholders.
- Invest in fisheries reform. Support fishers to transition to more sustainable fishing methods with new fishing technologies and retraining.
- Adopt policies to prevent bottom scarring by other fishing methods. Regulation of haul seining in the Chesapeake Bay greatly reduced scarring of seagrass beds in heavily fished areas.
Create and enforce Marine Protected Areas or Locally Managed Marine Areas in conjunction with local and Indigenous communities.
- Prioritize seagrass areas when siting MPAs. Considering both present and historical areas of seagrass can facilitate the return of seagrass. Water quality is also an important consideration for ensuring seagrass health in MPAs.
- Account for the needs of local people for food security and livelihood when setting up Marine Protected Areas. Fishing over seagrass habitats is often crucial to local people’s ability to support themselves. MPAs with small-scale fisher involvement are more successful than MPAs that do not include fishers, especially when only local fishers are allowed to fish there.
- Work with Indigenous and local communities to create community-based management for seagrass areas. Local communities often have extensive knowledge of seagrass species and habitats, as well as attitudes that make adaptive management successful. Community-based management has better outcomes than top-down management.
- See Marine Protected Areas Nexus for more information.
Create policies and legislation that facilitate restoration and preservation of seagrasses. Coordination and clear responsibilities among agencies are especially important.
- Explicitly protect seagrasses. Many seagrass hotspots do not have legislation or policies that can provide a framework for their protection.
- Use catchment or watershed-based coordinated management to maintain water quality in seagrass areas. Coordinating environmental management across a catchment has proven useful in Australia and New Zealand.
- Integrate management of coral, mangrove, and seagrass ecosystems. Only 18 percent of estimated interaction zones—where all three occur—are protected. Coral, mangrove, and seagrass systems are synergistic, so that the three habitats together provide more resilience and biodiversity. Seagrasses buffer storm surges for mangroves and protect reefs from sediment overload, pathogens, and ocean acidification. The ecosystem trio also increases coastline protection from flooding and wave impact. A regional plan for Caribbean coastal ecosystem protection provides a framework for managing the three ecosystems together.
- Cooperate with other countries to maintain seagrass habitats. The Dugong, Seagrass, and Coastal Communities Initiative is an example of international cooperation among seventeen countries that facilitates information sharing, raises awareness of community-based marine management, and leverages conservation funds.
Create economic incentives for seagrass protection and research. Incentives can provide alternative livelihoods, stimulus for conservation, and capacity for monitoring seagrasses. They can motivate behavior change.
- Consider payment for ecosystem services to support community-based management. Projects in Timor-Leste, Fiji, and Kenya can provide models for financial incentives for seagrass monitoring and management. A number of organizations are working on Blue Carbon financing for seagrasses.
- Incentivize or mandate ecologically friendly moorings. These moorings can protect seagrasses, but boaters have been slow to adopt them because of the extra expense.
Seagrass Restoration network (global)
Project Seagrass (global)
Blue Ventures (global)
World Seagrass Organization (global)
Ocean Conservation Trust (global)
Operation Posidonia (Australia)
Marnie Campbell (Australia)
Maricela de la Torre (Sweden)
Carlos M. Duarte, King Abdullah University (Saudi Arabia)
Richard Lilley (Scotland)
Marieke M. van Katwijk (The Netherlands)
Fleur Matheson (New Zealand)
Robert J. J. Orth (Virginia)
Richard K. Unsworth (Wales)
Leanne Cullen-Unsworth (Wales)
Michelle Waycott (Australia)
Seagrass: Life in the Underwater Meadows (3 mins.)
the Seagrass Habitat (Odyssey Earth) (4 mins.)
Sebadal/Seagrass (2 mins.)
Project Seagrass (2 mins.)
Seagrass-Watch videos (multiple)
Look After Your Bottom (2 mins.)
SAV: Restoring Our Underwater Prairies (9 mins.)
“Getting the Foundation Right: A Scientifically Based Management Framework to Aid in the Planning and Implementation of Seagrass Transplant Efforts,” Marnie L. Campbell (Bulletin of Marine Science)
“Global Analysis of Seagrass Restoration: The Importance of Large-Scale Planting,” M. M. van Katwijk, et al. (Journal of Applied Ecology)
“A Sea Under Pressure: Bottom Trawling in the Baltic” (WWW, 2020 Baltic)
Science and the Sea: Sharks and Seagrass (2 mins.)
Sea Grass: Posidonia Oceanica (5 mins.)
39 Ways to Save the Planet: Sublime Seagrass (14 mins.)
Blue Carbon—Seagrass Restoration Project to Add 4 Hectares of Seagrass Seedlings (SUFB 1153, 20 mins.)
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