Critically endangered eels are getting a “free pass” to England’s largest lake where they have not been seen in large numbers for 30 years.
Two eel passes which allow the fish to navigate weirs on the River Leven at Newby Bridge, Cumbria, are being installed by the Co-operative and the South Cumbria Rivers Trust in an effort to restore the species to Windermere. The European eel has seen its populations tumble in the past three decades, with numbers of young eels reaching Europe’s shores falling by more than 95 per cent from pre-1980 levels.
It is not known exactly why they are declining, but overfishing, loss of wetland habitat and barriers to their migration, such as dams and weirs on rivers and flood defences, are thought to be playing a part.
European eels start life in the Sargasso Sea, near Bermuda, and migrate across the Atlantic to Europe where they swim up estuaries and rivers to lakes and wetlands to live and grow for up to 20 years, before returning across the Atlantic to spawn.
The passes are made of bristle boards which will allow the juvenile eels to slither over the weir, helping them overcome the barriers that experts believe are a significant reason for the species being largely absent from Windermere for decades.
Chris Shearlock, sustainable development manager at the Co-operative Group, said: “As well as opening up quality habitat for this critically endangered species, an increased influx of juvenile eels will have wide-reaching biodiversity benefits because the eel plays a key role in the food chain of other species such as the otter and bittern.
“It is particularly exciting to think that this fairly simple piece of equipment will enable the European eel to be re-established in Windermere for the first time in more than 30 years.”
He said monitoring equipment would be installed to assess the benefit of the passes.
Pete Evoy, trust manager of South Cumbria Rivers Trust, said: “Eels should be common in the south Cumbrian rivers and becks but their population has declined fast in recent years. It is imperative that such a stressed population should be able to migrate easily from the sea into our freshwater systems.”
The Newby Bridge location is one of a number of places the eel passes are being installed in rivers in north-west England by the Co-operative and the Rivers Trust.