Vivid green seagrass is photographed underwater in the Isle of Scilly. The white sand seabed is visible, and the water is a bright turquoise blue.

Seagrass restoration

We're working to protect and recover seagrass meadows in UK seas, a vital habitat for animals and a key tool in the fight to combat climate change.

Seagrass is an incredibly important plant for the ocean and our planet, but it's extremely vulnerable to human activity and environmental change. Find out what we're doing around the UK to protect precious meadows.

What is seagrass?

Seagrass is a flowering plant that lives underwater around the UK’s coast in shallow, sheltered areas. It forms marine meadows which are highly productive ecosystems and biodiversity hotspots. The oldest seagrass meadows are thought to be hundreds of thousands of years old.

Seagrass meadows are one of the most important natural solutions to the climate crisis.

They play an important role in absorbing and storing carbon, and while seagrass can absorb 10% of the carbon buried in ocean sediment every year, it only covers 0.1% of the ocean floor.

A cat shark rests on the ocean floor surrounded by seagrass. It is face-on, with big black eyes and speckled skin.

A catshark in seagrass  |  Image credit: Ocean Image Bank, Sharron Moran

Why is seagrass important?

Carbon storage

Seagrass is the single most important species in the sea for locking in CO2. As a habitat it is far more carbon-rich and effective at absorbing carbon than an equivalent area of rainforest.

Protecting coasts

With rising sea levels causing coastal erosion, healthy seagrass blades – often up to 1m high – can reduce the power of waves washing away our sheltered coves and beaches.

Biodiversity hotspots

The UK’s seagrass meadows are home to the two species of seahorse which live in UK waters - the spiny seahorse and the short snouted seahorse. They're also breeding grounds for cuttlefish and sharks, and nurseries for cod, plaice and pollock.

A forest shelter

Seagrass is a complex ‘forest’ that supports and protects many animals, and increases the organic enrichment of the sand and muds around the root systems. This is a vital shelter and food source for molluscs, shrimp, crustaceans, anemones and other invertebrates to thrive in.

Threats to seagrass

The majority of UK seagrass beds - an estimated 92% - have been lost or damaged in the past century. Worldwide, at least 35% have been lost over the last 40 years.

The decline has been caused by industrial growth, modification of ports and sheltered harbours, boat traffic, and increasing, stronger storm events. Pollution within the water column also affects the light getting to the seagrass beds and increases the amount of ‘fouling’ algae on the seagrass strands.

A star-shaped snakelocks anemone can be seen in seagrass. It is quite alien-like, with a dark centre and over a dozen tendrils swaying.

Snakelocks anemone on seagrass  |  Image credit: Georgie Bull

10

%

of the carbon buried in ocean sediment each year is absorbed by seagrass

35

x

more CO2 is thought to be absorbed by seagrass than rainforests

92

%

of UK marine meadows may have been destroyed as a result of pollution, disease and damage caused by people

 

Alongside the loss of seagrass habitat over time, remaining meadows are damaged by anchoring, and the recreational use of our seas. The south coast, a tourist hotspot, is subject to the pressures and effects of large numbers of visitors, alongside the anchoring and mooring of vessels.

Anchoring has been found to rip up seagrass, damaging the grasses and their root systems as the anchors drag along the seabed. Moored boats also attract boats from outside the harbour which are looking for somewhere safe to anchor; more boats mooring and dropping anchors ultimately causes further damage to the seagrass.

A yellow buoy with 'no anchoring, seagrass restoration' written on it defends a protected seabed area. The project was in collaboration with Salcombe Gin.

A yellow buoy protects a sensitive seagrass area from anchoring. In partnership with Salcombe Gin  |  Image credit: Salcombe Gin

Conservation and restoration

Through numerous collaborative projects, focussed on the south coast of England, we're working to protect, restore and conserve seagrass habitats.

Boating

Since 2019, we've been working to support the replacement of traditional block-and-chain moorings with sophisticated Advanced Mooring Systems. So far, we’ve replaced five traditional block and chain systems that scraped across the seabed, ripping up seagrass, with mooring ‘riser’ chains which are suspended above the seabed using submerged buoys.

An additional significant benefit is that we’ve used screw piles to secure the riser chain to the seabed rather than the concrete-filled tyres commonly used to hold down moorings. Already there are signs of seagrass regeneration close to the moorings themselves since installation in spring 2019.

Water quality

The Marine Conservation Society has long been campaigning for significantly improved water quality in our seas. When waters are polluted there is less light for photosynthesis to take place in marine plants such as seagrass. Polluted waters also mean an increase in the amount of algae growing on seagrass blades and in the water column – both of which are bad for the health of seagrass.

More needs to be done over combined sewage overflows and farming practices which can leach nitrogen, pesticides and other chemicals into our rivers and ultimately into our coastal waters.

Fishing

Since 2009, we've been working to get damaging fishing (trawling, scallop dredging) out of seagrass beds in English Marine Protected Areas (MPAs). In 2014 we were successful in getting regulators, like the local inshore fishing authorities, to protect all English seagrass beds in MPAs.

Trawlers and dredgers sometimes ‘cleaned their gear’ by towing it through seagrass – thankfully that is now illegal. However, there is still an issue with recreational fishers digging out bait from muds and intertidal seagrass beds in places such as Essex and the Solent. It’s essential that this sort of activity is stopped through the use of measures like no access zones, voluntary codes, and information to fishers.

Seagrass and habitat restoration projects

A seagrass meadow is photographed from the seabed, looking up to the blue water

Saving seagrass in Plymouth
4 staff members from the Natur Am Byth porject stand huddled together on a jetty, smiling at the camera, as the sun shines behind them

Natur am Byth! Seagrass, native oysters and the pink sea fan
Sandeels swim above a seagrass meadow. With shafts of sunlight shining through the water, there's a stunning contrast between the vibrant green seagrass and the clear blue water.

Safeguarding marine habitats