Seagrass protection and recovery
Information and guidance on UK seagrass, the value of this important marine habitat and the Marine Management Organisation's role in supporting its protection and recovery in England.
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Seagrass – Our hidden marine habitat
Seagrass is an underwater flowering plant. It is the only marine flowering plant able to survive and pollinate fully submerged. Once found widespread across the UK, our seagrass beds have declined by over 40% since the 1930s (Green et al., 2021). This is mainly due to coastal development, pollution and wasting disease, as well as physical disturbance.
Seagrass form beds, or meadows, in shallow coastal areas (intertidal and subtidal regions) where they receive plenty of light. They also prefer sheltered bays and lagoons protected from significant wave action.
There are two recognised species of seagrass in the UK:
Common eelgrass (Zostera marina)
Found in deeper water (intertidal to sublittoral region), in fully submerged conditions to about 10 meters deep typically on sand, mud or course gravel. It is the largest British seagrass and forms dense beds, with trailing leaves up to 2 meters long.
Dwarf eelgrass (Zostera noltii)
Found closer to the shore (intertidal to shallow subtidal region) on fine sand and mud. It forms dense beds, with leaves up to 20cm long.
Both species grow horizontal stems (rhizomes) which spread under the substrate, rooting it firmly to the seabed. It also has air pockets (lacunae) in the veins of its leaves to help the seagrass blades float in an upright position in the water.
It is an important part of our marine ecosystem, serving as a nursey and home for a wide variety of marine species. Watch this short clip to see what life can be found in a seagrass meadow: Seagrass video.
The protection and recovery of seagrass will benefit people, coastal communities and the environment, through the vital ecosystem services it provides.
Seagrass in Helford River ©MMO/Francesca Della Valle
The value of the UK’s underwater meadows - Ecosystem services
Seagrass is one of the most valuable coastal ecosystems and provides a range of ecosystem services.
An ecosystem service is a way in which nature (natural capital) contributes to human existence, wellbeing and quality of life. Seagrass beds contribute to the maintenance of fish and shellfish populations providing stock for our seafood industry. This ecosystem service subsequently brings benefits to society, through food, nutrition and employment. Other ecosystem services include:
A safe and diverse habitat
As its name suggests when thriving, seagrass can form underwater meadows of swaying grass fronds, providing a safe habitat for a huge diversity of life, hiding juvenile fish, crustaceans and seahorses. Seagrass meadows are a nursery and feeding ground for fish and invertebrates improving biodiversity, increasing density and supporting commercial fisheries.
Coastal protection
Seagrass beds provide an important service to coastal communities through coastal protection. The rhizomes stabilise sediment that helps prevent erosion. The leaves also slow down currents and absorb wave energy that buffers the impact of storms and waves. Seagrass also improves water quality, acting as a filter for low-levels of pollutants and nutrient runoff.
Carbon storage
Seagrass plays a significant role in global carbon storage and the potential mitigation of climate change. It is responsible for over 10% of the buried organic carbon in the ocean. When seagrass photosynthesises it takes carbon from the atmosphere and stores it in its leaves. When the plant dies, this carbon is buried and stored in the sediment.
Carbon is also captured in the form of organic material within the base of seagrass blades and locked in the sediment. This is known as ‘blue carbon’. The loss of seagrass beds leads to the loss of their carbon sink capacity, and potentially the release of carbon previously stored in their sediments.
Tourism and wellbeing
As seagrass meadows occur in shallow water or intertidal areas, they create tourism hot spots for wildlife watching and watersport enthusiasts such as swimmers and snorkelers.
Download the ReMEDIES seagrass infographic to learn more.
Seagrass with anemones worms - Fal and Helford
Risks to seagrass
Seagrass is delicate and can be easily damaged by traditional moorings, including the dropping and weighing of boat anchors, which can drag along the seabed, expose the roots, leave large anchor scars, fragment the habitat and permanently damage the seagrass beds beyond recovery. It can be damaged by marine recreational activities such as launching of leisure boats, as well as other shore and water-based activities.
Excessive nutrient runoff into the sea from farms (agricultural feritilsers) and waste water from urban areas, can cause algae growth (eutrophication) and increase sediment in areas where seagrass is found. This can smother seagrass by reducing availability of light.
Increased ocean temperatures, ocean acidification and large storm events, as a result of climate change, also have a detrimental effect on seagrass.
Direct damage can result from dredging for coastal development.
How you can protect our seagrass meadows
Here’s what you can do to protect it
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Check navigational apps for mapped seagrass or sensitive marine habitats and avoid anchoring in those locations
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Use Advanced Mooring Systems (AMS) or ecomoorings where provided. How do Advanced Mooring Systems work?
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Find out more about the marine licensing process, timescales and any associated fees
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Respect Voluntary No Anchor Zones
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Avoid entering or leaving the sea through intertidal seagrass beds
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Replace your mooring (on seagrass) with an advanced mooring system
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Learn more about seagrass and tell others all about it
Our role in protecting seagrass
We have duties, alongside other public authorities for furthering the conservation objectives of marine protected areas. MMO are responsible for assessing and managing the impact of marine non-licensable activities (mNLA) to further the conservation objectives of inshore marine protected areas within 0-12 nautical miles (nm) in English waters. This includes MPAs where seagrass is a feature or supporting feature of the site.
It is within our remit to introduce appropriate management measures if required.
Learn more about Managing marine non-licensable activities in marine protected areas - GOV.UK (www.gov.uk)
Studland Bay Marine Conservation Zone
An example of an MPA protecting seagrass is Studland Bay Marine Conservation Zone (MCZ). Studland Bay is located on the South coast of Dorset, is renowned for its sandy beaches, sheltered waters, anchorage and stunning views. Hidden below the surface lies a vital seagrass habitat offering numerous benefits to the local community, environment and economy.
The Studland Bay ecosystem is threated by several factors such as climate change, ocean acidification, water quality and the physical impacts of anchors from high levels of recreational boating. Dropping anchors into the seagrass beds can damage and uproot the seagrass, impacting the many species sheltered by the seagrass. This damage also affects the health and functioning of this habitat, impacting its ability to provide critical services benefiting society, including carbon storage and flood protection.
The Studland Bay Marine Conservation Zone (MCZ) was formally designated on the 31 May 2019 and covers 6 nautical miles along the Dorset coast. The MCZ protects 4 designated features: the seagrass beds, intertidal coarse sediment, long-snouted seahorse (also known as spiny seahorses) and subtidal sand. A voluntary no anchor zone (VNAZ) was introduced in 2021 to manage anchoring impacts on the seagrass bed.
Find out more about managing marine non-licensable activities in Studland Bay.
Supporting seagrass restoration projects – guidance for partners and coastal communties
The aim of seagrass restoration is to restore our seagrass meadows through the protection of existing, and creation, of new seagrass habitats. This will ensure they continue to provide vital ecosystem services which benefit us all.
As with any restoration, it should start with pressure removal to allow any restoration projects the best chance of success. This may include:
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Management measures for marine recreation
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Alternatives to anchoring
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Replacing traditional moorings with advanced mooring systems (for more information: Moorings, consents and advice - GOV.UK)
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Addressing water quality issues
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Removing pressures from fisheries (including bait collection)
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Raise awareness of impacts from developments near to seagrass which may impact their condition
There are a number of local restoration projects creating new seagrass bed habitat around the UK. These consist of various methods including the collection of seeds from a healthy seabed to cultivate in a lab and then relocating mats of adult plants into the sea at the restoration site. Another technique involves distributing seeds directly in the restoration site, known as reseeding.
The restoration of seagrass is managed through the MMO marine licensing process. The collection of donor seeds and deployment of seeds or plants to the restoration site may require an application to MMO marine licencing for determination. It is up to the applicant to determine if they require a marine licence for activities in the marine environment: Do I need a marine licence? - GOV.UK (www.gov.uk) Please see our website for further information on the marine licensing process, timescales and any associated fees: Make a marine licence application - GOV.UK
It is an offence under section 140 of the Marine and Coastal Access Act 2009 to intentionally pick, collect, cut, uproot or destroy, any plant in an MCZ which is a protected feature of that MCZ.
MMO recommends following the seagrass and seahorse diving guidance note when diving or snorkelling in areas of seagrass or known seahorse locations.
You must have a wildlife licence if you are diving or snorkelling and intending to do something likely to disturb seahorses. This could be diving in a known seahorse location, taking photographs or filming seahorses.
As a wild flowering plant, the removal or uprooting or moving of seagrass plants is prohibited and managed by license under the Wildlife & Countryside Act (1981).
Natural England advise that anyone with plans to collect seagrass seeds or plants should liaise with Natural England on methods and suitable locations prior to this collection, to enable projects to progress swiftly without hindering recovery of designated seagrass beds and avoid committing an offence.
Further advice on restoring seagrass can be found here:
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Seagrass Restoration Handbook - CaBA (catchmentbasedapproach.org)
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ReMEDIES Seagrass Cultivation & Restoration Best Practice Guide
Seagrass restoration - best practice case studies
ReMEDIES
ReMEDIES stands for Reducing and Mitigating Erosion and Disturbance Impacts Effecting the Seabed.
The LIFE Recreation ReMEDIES project focused on how sensitive seabed habitats are impacted by recreational activities and provides a number of case studies which demonstrate how varied management measures can be effective. It aimed to reduce recreational pressure, restore seagrass habitats and promote awareness.
The project installed advance mooring systems (AMS) to protect the seagrass, and implemented Voluntary No Anchor Zones (VNAZ) to manage access to seagrass beds. The Royal Yachting Association (RYA) Green Blue advises best practice for recreational boating providing the Green Guide to Anchoring and Moorings to help minimize disturbance, and identifying UK seagrass bed locations to inform boaters of where to be more vigilant when considering an anchor spot.
Active restoration was key to the ReMEDIES project. The Ocean Conservation Trust planted a total of eight hectares of seagrass meadows within two Special Areas of Conservation (SAC).
The ReMEDIES end of project summary states “The project made great strides in the understanding, preservation and restoration of vital marine habitats, and identified areas for future research and improvement”.
Ocean Conservation Trust
The Ocean Conservation Trust exists to protect and restore the ocean. Their vision is a world where the ocean is thriving, healthy, and sustainably protected for generations to come. The Ocean Conservation Trust’s Blue Meadows project is a holistic approach to seagrass protection, regeneration and restoration at scale.
The goal is to protect the seagrass we already have, and over the longer-term restore the seagrass we have lost. ‘Blue Meadows’ places local communities at the heart of its work through community engagement, enabling coastal communities to feel inspired and empowered to help protect their local seagrass meadows and equipping them with the resources to do so.
The Ocean Conservation Trust are dedicated to making the ocean accessible to all and have developed an immersive experience, so everyone can explore the wonders of seagrass, no matter their age or where they live.