‘Eel lanes' being created in South Downs rivers to assist 4,000-mile migration

Yahoo

23-07-2025

Dedicated 'eel lanes' are being created in the rivers of the South Downs National Park to assist the migration of the European eel, which makes an 'incredible' 4,000-mile transatlantic journey from its breeding grounds in the Sargasso Sea.
The project has been launched by the park authority, which is working with the Western Sussex Rivers Trust to protect the habitat of the eel in the Rother and Ems rivers.
It includes the installation of 'fish passes' being created around man-made structures in the rivers which act as a narrow lane of water to provide eels with a route around artificial barriers such as dams and weirs.
And eel brushes – strips of bristles – are also being added at new water control structures in RSPB Pulborough Brooks and Pagham Harbour to help eels manoeuvre upstream.
A spokesman for the national park said: 'The migration of these eels is quite extraordinary as they undergo several metamorphoses during their lives.
'Spawning in the Sargasso Sea, off the coast of Bermuda, the eel eggs hatch into wriggling pea-sized larvae that have the appearance of a see-through leaf.
'Over the next couple of years, these opaque creatures drift along with the Gulf Stream, their bodies elongating as they enter the next life stage as a 'glass eel'.
'Upon reaching the English coastline, they use the force of the tides – and their new-found body shape at around 8cm in length – to push themselves upstream to make a home in rivers, including the Rother and Ems.
'Once in rivers, they go through more life cycles, growing up to one metre in length and living for up to 20 years, gorging on fish, molluscs and crustaceans.
'The end of their lives sees a fantastic finale. Entering the 'silver eel' stage, their pectoral fins widen, muscle mass increases, their digestive tracts shut down and their eyes grow up to 10 times their original size, all to help see them through one final swim.
'Fighting their way back against strong currents, silver eels head 4,000 miles back across the Atlantic to the Sargasso Sea to spawn.'
Aimee Felus, chief executive of the Western Sussex Rivers Trust, said: 'The health of our rivers here in the South East is crucial to the quality of our coastal waters, and vital to the health of the many creatures who call these fresh and salt waters home.
'Through our River Guardian monitoring project we are pushing for higher water quality improvements, quicker identification of pollution incidents and raising awareness of how all communities can get involved to help protect their local rivers.
'By removing man-made structures which limit how easily fish species, including the extraordinary eel, can move around, we are helping improve migration routes and their ability to reach better feeding spots.
'With pollution, sewage and drought all playing a part in the diminishing water quality of our rivers and streams, it's more important than ever that we work together to help protect and enhance these precious habitats for wildlife and humans alike.'
Jan Knowlson, biodiversity officer for the South Downs National Park, said: 'The eels we have in the national park are truly remarkable and their incredible migration underlines the important connection between our rivers and seas.
'There's a continuum and all these watercourses are joined up. So healthier rivers ultimately mean healthier seas and vice versa.
'Here at the South Downs National Park, we have eight large river systems, dozens of chalk streams and a sizeable coastline and know that having well-managed, cleaner waterways are absolutely paramount to nature bouncing back across this vast region.'