Islanders asked to report sightings of rare eel

Islanders Urged to Report Sightings of Critically Endangered European Eel in Guernsey

Guernsey’s Nature Commission is appealing to residents to report sightings of the European eel, a critically endangered species, to help assess and protect local populations. The call follows decades of sharp decline in eel numbers across the island, driven largely by habitat loss and barriers preventing access to inland feeding grounds.

The European eel, Anguilla anguilla, is classified as critically endangered on the International Union for Conservation of Nature (IUCN) Red List, placing it among the species most at risk of extinction globally. Once abundant in Guernsey’s freshwater systems, the species has seen a 95 percent population drop since the 1980s due to factors including drainage, pollution, and infrastructure such as dams and pipes that block migration routes. Ecologist Charlotte Burgoine, working with the Nature Commission and Guernsey Water, is leading efforts to map remaining eel habitats using environmental DNA (eDNA) testing in ponds and streams.

“The European eel has a unique life cycle,” Burgoine explained. “It hatches in the Sargasso Sea in the Atlantic, migrates as glass eels to freshwater environments like those in Guernsey, grows to adulthood, and then returns to the Sargasso to spawn—often after decades.” She noted that while eels can live up to 80 years and are strong nocturnal hunters, their survival is now threatened by increasingly fragmented freshwater habitats and coastal infrastructure.

Fragmentation of habitats prevents eels from moving between waterbodies, isolating populations and reducing genetic diversity. Pollution and poor habitat management further weaken their resilience. “These declines are happening worldwide,” Burgoine said, “so understanding the situation here in Guernsey is vital for the species’ conservation.”

The Nature Commission is encouraging islanders to share any recent or historical eel sightings, or knowledge of areas where eels were once common. The public can submit observations to support ongoing research and conservation planning.

Environmental DNA testing is already underway in Guernsey’s freshwater systems to detect eel presence without disturbing wildlife. Results will help guide habitat restoration and barrier removal efforts, potentially aiding eel recovery.

Guernsey Nature Commission and Guernsey Water are collaborating on this initiative as part of broader efforts to protect the island’s biodiversity and meet international conservation targets.

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