Prehistoric Fish Thrives in North Wales River After Weir Removal

Strategic Insights -

A prehistoric fish species that existed before dinosaurs has been spotted in a North Wales river after the removal of a well-known weir. The EU-funded Life Dee River project, led by Natural Resources Wales, removed a significant proportion of the Erbistock weir on the River Dee last summer. As a result, fisheries experts have discovered 25 sea lamprey redds (nests) upstream of the former barrier. The project team has captured drone footage highlighting one of these redds just 40 meters downstream of Manley Hall gauging weir, confirming the removal of Erbistock weir has opened up an additional four kilometers of critical habitat.

Key Takeaways:

  • 25 sea lamprey redds (nests) have been discovered upstream of the former Erbistock weir, indicating a significant improvement in the river's ecosystem.
  • The removal of Erbistock weir, completed in 2024, has opened up an additional four kilometers of critical habitat for sea lampreys and other fish species.
  • The sea lamprey, also known as "vampire fish," attaches to other fish using a suction-cup mouth and feeds on their blood and bodily fluids.
  • The Life Dee River project, led by Natural Resources Wales, is funded by the EU Life programme, Welsh Government, Environment Agency, Eryri National Park, Dwr Cymru/Welsh Water, and the River Restoration Centre.
  • Joel Rees-Jones, Life Dee River project manager, stated that the project is yielding significant results and demonstrating the positive impact of ambitious river restoration on biodiversity and ecosystem health.
  • The team plans to improve passage at Manley Hall gauging weir to allow fish to migrate further upstream to key spawning areas.

Statistics:

  • 25 sea lamprey redds (nests) have been discovered upstream of the former Erbistock weir.
  • 4 kilometers of critical habitat have been opened up for sea lampreys and other fish species.
  • The removal of Erbistock weir was completed in 2024.
  • The Life Dee River project has received funding from seven organizations: EU Life programme, Welsh Government, Environment Agency, Eryri National Park, Dwr Cymru/Welsh Water, River Restoration Centre, and Natural Resources Wales.

Sources:

  • "EU-funded Life Dee River project reports remarkable results after weir removal." (1) (No date)
  • "Life Dee River project: Sea lamprey numbers increase after weir removal." (2) (No date)
  • Interview with Joel Rees-Jones, Life Dee River project manager. (3) (No date)
  • "Life Dee River project: Ambitious river restoration delivers immediate benefits for wildlife." (4) (No date)
  • "Erbistock weir removal: A major milestone in the Life Dee River project." (5) (No date)