By DIVE Staff
A project to install specially adapted mooring buoys to protect the seabed of Plymouth Sound in Cornwall, UK, has resulted in a significant regrowth of seagrass in the area of its implementation.
Led by the Marine Conservation Society and the Ocean Conservation Trust, the initiative uses an ‘Advanced Mooring System’ which reduces the impact of anchors and dragging chains on the sea floor.
Seagrass meadows around the UK have declined by as much as 90 per cent over the past century, the result of coastal development, disease, pollution and increased boating activity. An increase in recreational fishing and pleasure boating since the 1990s has been particularly damaging to coastal seagrass meadows.
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Seagrass beds are a vital coastal ecosystem, providing essential habitats for many species, and serving as nurseries for many others. Seagrass also acts as a buffer to storm damage, helps to reduce coastal erosion, and is a valuable source of ‘blue carbon’ sequestration.
The project began in 2019 with the installation of five Advanced Mooring Systems in Cawsand Bay, Plymouth Sound, one of the busiest areas of the Plymouth Sound Special Area of Conservation (SAC), particularly with regard to tourism and small boat use. A further 12 moorings were added in 2021
Traditional moorings consist of an anchor block and a chain attached to a buoy. The chain, however, can drag on the sea floor, creating a ‘halo’ around the block as the boats moored to it swing with the wind and tides. The repetitive nature of the chain-dragging not only damages the seagrass, but also prevents its recovery.
To minimise this damage, the Advanced Mooring System installed in Cawsand Bay uses buoys, floats or bungee-type devices to keep the chain off the seabed. Now, four years later, MCS has reported a 212 per cent increase in seagrass cover within the mooring area.
Together with the huge increase in seagrass area, the MCS Plymfish project reports a 70 per cent increase in the number of animals present in the bay, and a 7 per cent increase in the number of different species present in the grass, compared to surrounding sandy areas.
‘It’s incredibly rewarding to see the seagrass meadows reappear after the installation of the Advanced Mooring Systems, restoring a vital habitat for local biodiversity, carbon storage and coastal protection,’ said Dr Jean Luc-Solandt, MCS’s Marine Protected Areas Principal Specialist.
‘You can’t get restoration without protection, and by working with the local boating community to protect the seabed, we have collectively given space for this rewilding to take place. Against the backdrop of the climate and nature emergency, the success of this simple system shows how pioneering projects can have a mitigating effect on the impacts of climate change, and reverse local biodiversity decline.’
Mark Parry, Head of Ocean Habitat Restoration, at the Ocean Conservation Trust, said: ‘We are delighted to see the positive effect the installation of the Advanced Mooring Systems has had to increase the presence of seagrass in Plymouth Sound, it’s a big win for this sensitive habitat.
‘Protecting and restoring seagrass requires a holistic approach and by finding workable solutions like this, it allows communities to continue enjoying the ocean, whilst having a lesser impact on the environment, allowing both people and nature to peacefully coexist.’
MCS says it will be expanding the mooring buoy projects to other sites and is asking interested boaters to get in touch with the charity for more details.
