Coastal rewilding: restoring Scotland’s seagrass meadows


Viewed through a snorkel, a seagrass meadow in the clear waters of Scotland’s Loch Craignish is a fine sight. Long green blades of the underwater flowering plant, also known as eelgrass, sway gently in the tidal current, while in their shade multicoloured crabs face off near the half-buried shell of a native oyster.

It is a scene that was common in UK coastal waters before pollution, disease and marine exploitation wiped out vast swaths of seagrass, destroying in the process nursery grounds for multiple fish species and shelter for once-abundant wild oysters.

Loch Craignish locator map

But in Loch Craignish in western Argyll, Danny Renton, project co-ordinator for the Scottish charity Seawilding, hopes this tale of ecological degradation can be turned around.

The innovative scheme to recreate the sea loch’s natural oyster beds and expand its small surviving seagrass meadows could be a model for the restoration of these vital marine ecosystems around the UK, Renton said.

“We want to create methodologies by which we can do these things at community level at low cost, and which are replicable and transportable,” Renton added, after a few hours spent putting 60,000 juvenile oyster spats in floating cages.

“We are talking about turning Loch Craignish into a seagrass restoration training ground.”

Success for the project, which is funded by Scottish government agency NatureScot, would have far more than local significance.

A University College London study last year estimated that the UK may have lost more than 90 per cent of its historical seagrass meadows, preventing the storage of millions of tonnes of carbon dioxide equivalent.

Making up some of those losses could offset carbon emissions elsewhere while helping to increase other marine resources. Seagrass beds provide shelter for shellfish and numerous fish species, including the young of commercial catches, such as cod, plaice and flounder.

Danny Renton, of Seawilding – a native oysters and seagrass restoration project – empties jugs of baby juvenile oysters into cages in Loch Craignish where they will then grow
Danny Renton, of Seawilding — a native oysters and seagrass restoration project — empties jugs of baby juvenile oysters into cages in Loch Craignish where they will then grow © Jeremy Sutton-Hibbert/FT

Research shows these underwater meadows are highly efficient at capturing and storing carbon in marine sediments, giving them a potentially important role in reducing climate gas emissions.

As well as absorbing carbon directly, seagrass root networks trap and bind organic detritus in underlying deposits. NatureScot cites research that suggests the marine plant may be responsible for about 15 per cent of carbon storage in the ocean despite covering only about one per cent of the sea floor.

Pioneering projects in the US have shown that seagrass meadows can be successfully restored. Virginia Institute of Marine Science researchers, for example, were able to cultivate more than 2,000 hectares of once barren seabed and to reintroduce bay scallops to the area.

UK Research and Innovation, a government funding body, in July announced a grant of more than £750,000 for UK seagrass recovery research that organisers plan to use to develop the science and “strategic vision” for renewal of “these powerhouses of our coastal seas”.

“In the context of generally improving long-term water quality and improved management of our coastal seas . . . seagrass now provides an opportunity for environmental renewal through large-scale restoration,” they wrote.

Renton said Loch Craignish, with its relatively clean waters, was a good place to try out restoration techniques. As well as its small surviving seagrass meadows, the sea loch still supports a few native oysters, their gnarled shells growing as big as a person’s hand.

Still, marine life in the loch today is a pale shadow of what it was in Victorian times, when one enthusiastic visitor declared the Craignish seabed offered an “incomparable” bounty for a prospecting marine zoologist.

William Goudy, Seawilding’s seagrass project manager, looks for older, native oysters during low tide at the coastal loch
William Goudy, Seawilding’s seagrass project manager, looks for older, native oysters during low tide at the coastal loch © Jeremy Sutton-Hibbert/FT

To expand the native oyster population, Seawilding buys sprats about the size of a £1 coin from a supplier in England, grows them in cages for a few months and then carefully distributes them on the seabed to take their chances with hungry starfish and crabs.

For seagrass restoration, seeds must be collected underwater, then washed using specialist equipment and stored in cold water for later planting in hessian bags. Increasingly mechanised approaches that are used in the US are unlikely to be suitable for smaller bays.

“It’s very labour intensive . . . you need a lot of people to be onboard and willing to lend a hand,” said William Goudy, Seawilding’s seagrass project manager.

At the end of August, the charity invited snorkellers and members of the community to help with its seagrass seed harvest and see its new £15,000 seed-processing equipment in a local boat shed. Volunteers have already gathered 100,000 seeds which will be replanted in October or November.

The process is being carried out under the guidance of Project Seagrass, an environmental charity already involved in seagrass meadow restoration in England and Wales. But Richard Lilley, Project Seagrass co-founder, said the Loch Craignish scheme was the first in the UK that was locally run, an approach he hoped would spread to other areas.

“The idea is the community is doing everything and we are just supporting,” Lilley said.

Goudy said the key to success would be demonstrating how to scale up oyster and seagrass restoration cheaply. “We are going to be writing a handbook,” he said.

Renton even dares to dream that the community approach might one day help to bring back the rich marine meadows and vast oyster reefs that until the 19th century graced Scotland’s now heavily industrialised and badly denuded Clyde and Forth estuaries.

“Those are the golden grails,” he said.

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