Sitting on the seabed, they look like the ancient totems of some long-forgotten civilisation; an Atlantis of the Mediterranean.

But an unusual initiative in which 39 huge stone sculptures were positioned on the sea floor off the coast of Tuscany is reaping rewards.

The idea was that the sculptures would snag the nets of the many illegal trawlers that were targeting the area, deterring them from poaching.

Conservationists and local fishermen now say that six years after the start of the project, it is working, with populations of fish and crustaceans recovering after years of decline.

A pod of dolphins has even established itself in the large bay off the coastal town of Talamone, and lobsters have returned after decades of being absent.

It has been such a success that there are now plans to position more sculptures on the seabed further north along the Tuscan coast.

“It’s great, very gratifying. There are now fish and jellyfish and 15-inch-long anemones. It shows that if you give the sea a chance, it will recover,” said Emily Young, a British sculptor who contributed two 20-tonne sculptures to the project, the first of which was lowered from a barge in 2015.

“The problem was that vast dredging trawlers were operating illegally along the coast, tearing up the seabed and seagrass meadows, destroying everything.

“The idea of the sculptures is that they snag the trawlers’ nets, which are very expensive to replace.” 

Born in London but now living near Grosseto in Tuscany, her grandmother, also a sculptor, was a colleague of Auguste Rodin and the widow of the explorer Captain Robert Falcon Scott of Antarctic fame.

The idea of deterring illegal fishing with sculptures was conceived by Paolo Fanciulli, a 60-year-old local fisherman whom Ms Young describes as “a visionary”.

Populations of snapper, bream, red mullet and other species have all bounced back since the sculptures were placed along a 10-mile stretch of the seabed.

“Even the lobsters are back - we hadn’t seen them for 35 years,” he said.

The sculptures are made of huge chunks of marble, which were donated for free by the owner of a marble quarry at Carrara in Tuscany, in the mountains where Michelangelo sourced his marble.

“The marble is veined with grey rather than pure white, which makes it hard to sell. It was going to waste, just sitting there,” said Ms Young, one of a dozen international and Italian sculptors who contributed her time and work for free.

“We’ve managed to totally stop the illegal fishing in the area,” said Ippolito Turco, the president of an association that looks after the sculptures.

"Now we’re looking at extending the project along the coast to the north. We want to put more sculptures on the seafloor. It has proved to be very effective.”

The carved blocks of stone are not just a way of tackling illegal dredging - they also form an underwater sculpture park. At a depth of eight metres, they are too deep for most snorkellers but they can easily be explored by scuba divers.

“What you want to happen is that in time, you won’t know they are sculptures. They will be so covered in seaweed and algae that they will look like a coral reef or the remains of a wreck,” said Ms Young.

“I like to think of the archaeologists of the future, a thousand years from now, coming across the sculptures and thinking perhaps that they are the remains of an ancient civilisation.”

Telegraph Media Group Limited [2021]