Isabella Tree catches up with Carl Sayer, Professor of Limnology & Freshwater Ecology at University College London – aka the Eel Man – as he prepares for this year’s survey of Knepp’s eels. Once bountiful in the UK, eels have all but disappeared from most water systems, impacted by overfishing and obstructive dams and weirs that prevent their migration. Carl has loved eels since he discovered them as a boy and relishes the mystery that still surrounds their adventurous lifecycle. Happily, his surveying at Knepp provides grounds for optimism and giggles all round for his students attempting to measure and weigh the slippery customers.

Isabella Tree co-founded the Knepp rewilding project with her husband, Charlie Burrell. She is the award-winning author of ‘Wilding’, which was made into a major motion picture in 2024.