Great Seagrass Survey surprises organisers – Divernet

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The inaugural Great Seagrass Survey, carried out by scuba-diving, snorkelling and strolling volunteers from last May, is now reported to have revealed 185 hectares of previously unsuspected seagrass beds in shallow UK coastal waters.

The survey, now set to be an annual event, is a collaboration between Scottish charity Seawilding and the British Sub-Aqua Club (BSAC), which say the aim is to encourage restoration of the ocean’s only flowering plant and the rich ecosystems it supports.

Seawilding, based in Loch Craignish in Argyll, is the UK’s first community-led native oyster and seagrass restoration project. “The biggest surprise was how much seagrass was found,” said project organiser Katherine Knight, the charity’s science & survey officer.

Collecting data on seagrass health during the Great Seagrass Survey (Seawilding)
Collecting data on seagrass health (Seawilding)

“Most of the beds they discovered aren’t included in official records and could have been undiscovered for centuries, so this is ground-breaking stuff. By knowing where seagrass is, more can be learnt about the threats it is facing, as well as what is required to conserve it.” 

Seagrass habitats worldwide are under threat, with beds having declined by an estimated 92% and areas the size of a football pitch (1.05 hectares) being destroyed every half-hour, according to the survey organisers.

‘Notoriously hard to restore’

Great Seagrass Survey volunteers mapped 96 beds around the UK, from the Outer Hebrides to the Channel Islands, looking for the Zostera noltei species on beaches at low tide and Zostera marina in shallow waters. The largest area mapped was by the Moray Ocean Community near Inverness, at 78 hectares.

Data was uploaded to the BSAC website, to be analysed, collated and shared by Seawilding through national databases accessible to scientists and policy-makers – and the survey is on-going.

“Although we were encouraging people to search for seagrass over the summer, the submissions page is open all year round and people can upload data or look for seagrass whenever suits them,” explained Seawilding charity administrator Tiziana Tedoldi.

“We’re a small team and have been busy harvesting, processing and planting seagrass, so hadn’t had a chance to sit down and analyse the data until this winter.” Locations of all the seagrass beds found so far can be viewed on this interactive map.

Great Seagrass Survey volunteers (Seawilding)
Great Seagrass Survey volunteers (Seawilding)

“Seagrass is notoriously hard to restore once it is lost, so these new beds are incredibly valuable for both biodiversity and carbon capture,” said Seawilding’s CEO Danny Renton. 

“We hope that these patches of endangered and unmapped seagrass – and the ones that the survey will reveal in the future – can be the cornerstone of new restoration projects inspired and driven by coastal communities.”

Great Seagrass Survey logo

“It’s great that volunteer BSAC scuba divers and snorkellers are helping to map UK seagrass beds,” commented BSAC CEO Mary Tetley. “As custodians of the underwater world, BSAC members are well placed to assist Seawilding and our environmental partners build up a picture of these precious coastal habitats and help protect them for the future. 

“The forthcoming BSAC Underwater Surveyor course will give members a great skillset for becoming citizen scientists.” Find out how to get involved in the Great Seagrass Survey in 2024.

Also on Divernet: Seagrass boost in Cornwall, brainwave in Australia, Biggest seagrass bed yet identified in CornwallSeagrass Project gets going In CornwallBlues Meadows Seagrass Project underwayWorld’s biggest plant revealed in Shark BayWe should fight to protect UK seagrass

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