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reef block


Custom-built reef to help protect white-clawed freshwater crayfish

ARC Marine – a small company based in South Devon – is aiming to protect the UK's indigenous white-clawed freshwater crayfish population from extinction with its first custom-built reef structure.

The reef is being built at Vobster Quay – an inland water site and former quarry near Radstock in Somerset, in a collaborative project with Bristol Zoo and the University of Plymouth.

The company designs and builds artificial reefs that can block illegal fishing trawlers, provide a protective marine habitat for endangered and declining species, boost the stocks of overfished species and protect coastlines and underwater habitats from erosion.

ARC Marine is funding its world-first operation through a crowdfunding campaign.

The reef's site was chosen due to its close proximity to Bristol Zoo, with which ARC Marine is collaborating in a bid to regenerate dwindling numbers of the globally-protected crayfish species.

Due to habitat destruction and the introduction of an aggressive and invasive US crayfish species, the white-clawed freshwater crayfish is at risk of becoming extinct in the UK within 20-30 years.

“Artificial reefs can be very useful in enhancing marine life, but also double up as anti-trawling devices,” said Dr Nicholas Higgs, Deputy Director of the Marine Institute at the University of Plymouth's COAST lab facility, which undertakes tests on structures built for a marine environment.

“They provide structure by concentrating fish and nutrients around the reef – creating a whole ecosystem. They also prevent fishing in that area as these big structures stop ships towing fishing and trawling gear through the area.

“The ARC modules provide increased habitat complexity. By providing that living space, you should be able to increase the amount of crayfish that can live in habits like quarries and manmade water bodies.”

Currently, only four per cent of the world's oceans are officially protected, according to WWF. A study published in the Nature journal found that 93 per cent of CO2 is stored in algae, undersea vegetation and coral – highlighting the crucial need to prevent marine degradation in order to protect the earth's atmosphere.


Overfishing is also an environmental problem in both the UK and abroad – with 53 per cent of the world's fisheries fully exploited, and 32 per cent over exploited, depleted or recovering from depletion, according to WWF.

At this current rate, research from scientists and ecologists shows that all species currently fished for food may collapse by 2048.

Tom Birbeck, co-founder of ARC Marine, is confident that the company can be a UK leader in reversing this trend. His decision to choose crowdfunding over commercial sales or grant funding aims to reflect the nature of the problem his company is trying to solve.

“Oceans and waterways belong to everyone. So the responsibility of marine conservation – and the challenge of reversing ocean degradation – is one that we all must tackle collectively,” said Tom.

“We're giving the crowd the power to rebuild and protect our delicate marine environment for generations to come, with a 500-plus year project lifespan. There is no pledge like it in the history of crowdfunding.”

ARC Marine – which was given a starting loan by Virgin Startup – was formed in 2015 to develop specific products to aid the rehabilitation of damaged reef seabeds that would last longer than ships, which have previously been used to create artificial reefs. It then began developing design prototypes including artificial reefs and sea grass habitats.

The company has created the world's first multi-functional artificial reef solution. With a strong, modular design, its reef systems protect against depth trawling, provide a superior marine habitat, can act as a robust anchor point for cages and buoys, and can protect marine structures and coastlines against underwater currents and erosion.