Thousands of invasive crayfish removed from Burrator Reservoir

South West Water has said it has ramped up its efforts to tackle invasive American signal crayfish at Burrator Reservoir, removing around 14,000 of the species over the past three years.

In a statement, South West Water explained that these aggressive invaders, introduced to the UK decades ago, now pose a significant threat to native ecosystems. 

They explained that the crayfish damage riverbanks, muddy waters, prey on native species, and carry a deadly disease that threatens the UK’s native white-clawed crayfish.

Burrator, one of the South West’s key reservoirs, provides drinking water to households across Plymouth and parts of South Devon. 

South West Water said that protecting both the reservoir’s water quality and biodiversity is a priority, and this large-scale operation is central to their efforts.

Following the 2022 drought, which caused water levels to drop to around 40 per cent, South West Water said they saw an opportunity to take more effective action. 

They stated that with the crayfish more vulnerable during lower water levels, their trapping efforts became more successful.

“We removed more than 6,000 crayfish in just three weeks during our latest round of trapping,” a South West Water spokesperson said. 

“That means fewer large males and far fewer females carrying eggs.”

In addition to trapping, South West Water is using underwater cameras to monitor crayfish activity in harder-to-reach areas. 

They are working with wildlife filmmaker Jack Perks to capture underwater footage, allowing the company to better understand the extent of the problem.

“Invasive species like the American signal crayfish are a big threat to the balance of our natural ecosystems,” said Kate Hills, South West Water’s Biosecurity and Invasives Manager. 

“They don’t belong here, and their presence puts both wildlife and water quality at risk. They can have a big impact on a water company, that’s why we’re doing everything we can to manage them, and it’s working.”

“We’ve carried out a large-scale control programme at Burrator, and over three years we’ve trapped nearly 14,000 crayfish. Anglers say they’ve already noticed an increase in invertebrate life within the reservoir.”

South West Water is urging anglers, walkers, and visitors to help prevent the spread of the crayfish, urging them to use wash-down stations and check their kit when visiting the reservoir.

“The more eyes we have on the water, the better,” they said.

Looking ahead, South West Water plans to expand the management programme to Roadford Reservoir while continuing their work at Burrator.