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Releasing eels will aid lake’s ecological revival

  • Categories : Press Release
  • 30 Jul 2018
Eels at Cyfarthfa

Eels are swimming in Merthyr Tydfil’s Cyfarthfa Lake for the first time in more than 100 years, after being reintroduced as part of a South Wales-wide biodiversity plan.

Talks between the South East Wales Rivers Trust, the County Borough Council and Natural Resources Wales have led to the eels’ release into the popular fishing lake following an invasion of American Signal Crayfish, an alien species.   

The crayfish are not only causing a nuisance for the anglers by eating young fish and destroying their habitat, but also burrowing into the lake’s masonry and causing leaks.

European Eels are a natural predator to young crayfish.   As they grow, the hope is that the eels will feed on the smallest crayfish, reducing their population and helping play a part in maintaining the lake’s ecological balance.

The Rivers Trust has been working to highlight the decline of the eel to schoolchildren and the wider public.  As part of the regional project, Trelewis Primary School pupils have been feeding and looking after the eels in Merthyr Tydfil.

Merthyr Angling Club member and South East Wales Rivers Association Chair Tony Rees MBE said: “This is part of a huge programme of work which is underway across Europe to help re-establish eel populations by restoring wetlands and removing barriers to the eels’ traditional migration routes.

“It’s been a delicate operation but if successful, will also play a massive part in restoring the ecological balance of waterways across Wales.”

Mayor Cllr Clive Tovey, the Council’s Biodiversity Champion Cllr Malcolm Colbran and Merthyr and Rhymney AM Dawn Bowden - along with 10-year-old Finley Williams of Troedyrhiw - helped release the eels into Cyfarthfa Lake.

Cllr Tovey said: “The Council is delighted to be a part of this positive project that will impact on the future biodiversity of the lake and assist with its sustainability and long-term maintenance.”

Dawn Bowden was recently made European Eel Champion as part of the Species Champion project run by Wales Environment Link (WEL).  WEL members – including Salmon & Trout Conservation Cymru and the Sustainable Eel Group – paired up a group of 37 AMs with endangered species in Wales so they can help recover and safeguard them.  

  • Young eels (called elvers) hatch from eggs in the Sargasso Sea - a deep part of the western Atlantic Ocean. They migrate 3,000 miles back across the Atlantic towards the coast of the UK, gather in large river mouths like the Severn Estuary, and then head upriver in search of a new freshwater habitat. 

The journey takes around two years and by the time they arrive, the eels are about 5cm long.  Male eels then spend around seven years and females up to 20 years in our ponds, rivers, ditches and other areas of water getting bigger all the time and reaching lengths of up to 60-80cm long.

They are then mature enough to breed and return to the sea and begin the long journey back to their breeding grounds, the Sargasso Sea, where they lay their eggs and die.  They are also the only fish commonly found all over Europe and unlike spawning salmon, are all from one population.

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