The Somerset Levels cover 69,000 hectares of wetland and coastal plain and have long been a stronghold for the European eel. Eel populations there are now in sharp decline. Drainage ditches (known locally as rhynes) and water management infrastructure were built to protect homes and farmland from flooding, but they have become impassable obstacles for migrating eels. An electric pumping station adds to the threat. In August 2023, the Somerset Eel Recovery Project (SERP) partnered with NatureMetrics to find out where eels were being blocked and to guide conservation action.

SERP urgently needed to pinpoint migration barriers across a complex, 69,000-hectare network of drainage ditches. Traditional survey methods were too expensive and time-consuming to give insight at that scale. SERP needed a standardised survey that:

• Could be repeated year on year
• Was simple enough for citizen scientists to carry out

NatureMetrics provided an easy-to-use, cost-effective eDNA solution that could deliver ecosystem-scale insight year after year:

• Survey design: Our survey design team worked closely with SERP to plan the survey, accounting for all the factors that affect eel migration.
• Sampling: Easy-to-use aquatic eDNA kits allowed standardised water sampling across the Levels.
• Analysis: Our laboratories carried out metabarcoding analysis to map where eel DNA was present or absent across the site.

The analysis found no eel DNA at any sample site in the drainage ditch network, yet eel DNA was present in the main rivers feeding the Levels. Eels could reach the area but couldn’t get into the wetlands. The results pinpointed infrastructure barriers as the critical disconnect. The electric pumping station was identified as a major threat, having cut the drainage network off from the rivers over decades of operation.

The findings led directly to conservation action. In 2024, SERP began installing eel-friendly ropes across barriers to help eels migrate upstream.

The project also:

• Sparked local interest: It renewed interest in reviving eel populations and strengthened local connections to the area’s cultural heritage.
• Secured further support: Stakeholders recognised the value of eDNA for conservation, which secured further support for eel monitoring.
• Built long-term momentum: It started longer-term work on eel monitoring and wetland health across the Somerset Levels. Analysing every species detected can establish biodiversity baselines and track changes over time.

The project is a strong model for how technology-enabled, collaborative science can drive measurable outcomes for Critically Endangered species.