The survival of white-clawed crayfish, which is listed as a rare and threatened species under Section 41 of the Natural Environment and Rural Communities Act (2006) has come under threat in England during the past three decades following the introduction of the invasive signal crayfish from America. This species is bigger, more aggressive, and can pass on the ‘crayfish plague’, which is deadly to the native crayfish. It also burrows into banksides, causing sand and soil blockages, or siltation, on watercourses.
To protect the native crawfish, the Environment Agency and Northumberland Rivers Trust have moved a large number of the species from abundant populations found in the river Wansbeck in Morpeth, which according to the agency is one of the ‘last remaining strongholds’ for the native crayfish, to six refuge sites, known as ‘Arks’, in North Northumberland.
According to the agency, as work is already being carried out at Mitford Dam, which is part of the Morpeth Flood Alleviation Scheme, the opportunity to move large numbers of the species has arisen.
Pete Kerr, director of the Northumberland Rivers Trust, said: “While Northumberland’s rivers do have some of the best remaining populations of native crayfish in the UK, the invasive signal crayfish are a constant and imminent threat.
“Many people haven’t seen a native crayfish but they are amazing creatures that play a vital ecological role. We need to do all we can to shelter them from harm and these new Ark sites will play a key role.”
The crayfish were collected under a Natural England conservation licence, using a combination of traps, stone turning and hand nets.
Ian Marshall, EA white-clawed crayfish National Species Lead said: “We’re in very real danger of this native species disappearing from our rivers. These new Ark sites will give them a chance to breed and build new populations to help secure their long-term future.
“It builds on the positive progress already made by ourselves and our partners in Northumberland to protect them.”