Normally people microchip their precious pets in case they wonder off – but now its eels getting chipped, to track them on a mysterious 4,000-miles journey.
The slippery customers are getting tagged so researchers can see what the critically endangered eels get up to when nobody’s watching.
The eel’s remarkable life cycle was shrouded in mystery for centuries. Unlike other migrating fish, eels begin their life cycle in at sea but then spend most of their lives in fresh water inland before returning to the ocean to spawn and die.
Eels famously travel thousands of miles across the Atlantic to the Sargasso Sea to breed. Their young then drift back to Europe, where millions head up the Bristol Channel into the River Severn, where they mature in freshwater.
But the eels are in trouble. Emma Hutchins, of the Wildfowl and Wetlands Trust said: “Numbers of glass eels returning to the UK have decreased by 95% in the past 40 years and they urgently need our help.”
Traditionally, eels would live out their lives in the wetlands of the Severn Vale before completing their life cycle by returning to the North Atlantic Ocean. However much of the eel’s wetland habitat has been lost and their path to the sea obstructed by man-made obstacles.
The researchers at Slimbridge in South Gloucester will study the impact of flood gates, pumps and old industrial structures like weirs on the eels.
The chips will automatically set off a reader placed on the main ditch leaving Slimbridge, letting them know when each individual has decided to migrate. The microchips can also be read by a hand held reader if the eels are caught in future, this will enable researchers to understand how eels are using the ditches and pools Slimbridge and track individual movements.
Eel spawn drift almost 4,000 miles from the Sargasso sea near the Caribbean to Europe. During their 300-day they metamorphose into a transparent larval stage known as glass eel, as they approach the continent.
They then transform again into elvers, miniature versions of adult eels. They take five to twenty years to mature into ‘silver eels’ which sparks their long journey back to the Sargasso Sea where it all began.
“WWT is famed for its conservation work with endangered migratory birds around the world, but the most endangered species living on our nature reserves is the European eel, also a master of long-distance,” said Emma
“As one of the biggest wetland areas within the Severn Estuary under conservation management, Slimbridge is an ideal place to enhance for eels and centre this conservation project.”