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United Kingdom

Porthdinllaen Village


Conservation benefit: Replanting of seagrass areas damaged by mooring chains; new ecomoorings

Date Approved: 06.2020


This project protects seagrass, which traps more CO2 than any other marine ecosystem, slowing global warming.

In the shallow waters of the Irish Sea, off the northern Welsh coast, is one of the UK’s most spectacular seagrass meadows. These productive, expansive meadows provide many benefits, including:

  • Wildlife food and shelter
  • Reduction of storm damage and erosion
  • Better water quality
  • Food and economic security for fishing communities
  • Carbon trapping that exceeds rainforests, acre for acre

Much of the seagrass in Wales, however, has been lost. It is critical to save what remains, both for the benefits it provides and as a source of seeds for restoration efforts. In sites where only patches are left, natural regeneration is difficult or impossible, and active restoration is necessary.

Near the town of Porthdinllaen, chains used to moor boats in the harbor have literally scarred the seagrass meadows. As the moored boats bob in the water, the chains drag on the bottom, tearing up seagrass plants. The denuded patches are visible on Google Earth.

This project, Seacology’s first in the UK, will restore at least ten separate scarred areas, totaling about a quarter of an acre. The acreage is small, but the impact could be big. Our partner, Project Seagrass, hopes that a well-executed restoration project will serve as a model, paving the way for much more expansive restoration.

Part of this project budget will be used to facilitate outreach, communication, and education with Porthdinllaen stakeholders. This includes bringing in a Welsh-speaking representative.

The planting will employ techniques used in successful restoration projects in Chesapeake Bay, adapted for the UK marine environment. After seeds are collected and prepared, they will be planted by hand, in burlap bags filled with sand, to protect them from the area’s high tides and abundant crabs.

Project Seagrass will also install several kinds of new seagrass-friendly boat moorings, designed for different kinds of boats.

Project Updates

February 2021

Our project partner has assembled a steering group that includes representatives from local government, nonprofits, and community groups. Scientists and volunteers came together to collect seagrass seeds in North Wales, and in October, 15,000 seeds were embedded in 300 burlap bags and planted by hand at Porthdinllaen. They were spread across two former moorings and an area damaged by a boat ramp. They plan to plant more seeds bags when COVID lockdowns allow.

Using detailed aerial imagery from drone flights over the harbor, they are measuring mooring scars in the seagrass. They are also in the process of choosing the new advanced mooring systems (eco-moorings) and getting permits to install them. Their aim was to have them installed in January (even with delays due to COVID-19), but Wales is back into a full lockdown, so the timeline is uncertain.

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