Porthdinllaen seagrass meadow
One of Wales’ largest seagrass meadows lies in the shallow water at Porthdinllaen (and north of Morfa Nefyn). It has provided seeds for new and restored meadows. The meadow shows as a dark patch on the map below.
Unlike seaweeds, seagrasses have leaves, roots, shoots and even flowers. Seagrass meadows are havens of biodiversity. They provide a habitat, food and shelter to thousands of species of fish, invertebrates, mammals, reptiles and birds. Porthdinllaen’s seagrass meadow is an important nursery for juvenile fish of commercial value.
Healthy seagrass meadows also trap carbon from the atmosphere and produce oxygen.
It’s thought that seagrass (morwellt in Welsh) was historically present in several parts of the coast but was lost, largely due to water quality issues including metal pollution from industries which have now gone.
The seagrass meadow at Porthdinllaen is estimated to cover the same area as 46 football pitches. It has been fundamental to piloting seagrass restoration in the UK, producing seed for site planting trials. It supplied most of the seeds for the UK’s first large-scale seagrass restoration project, at Dale, Pembrokeshire. In 2022 North Wales’ own Seagrass Ocean Rescue programme began, with the aim of planting common eelgrass (Zostera marina) across 10 hectares in North Wales by 2026 through pioneering seagrass restoration methods.
Seagrass seeds collected from the healthy meadow here are processed in aquaria, where the organic tissue surrounding the seeds rots away naturally to allow seeds to drop out and be collected. The Project Seagrass charity is trialling various planting methods, including hessian bags, dispenser injection seeding, clay balls mixed with seeds, and transplanting seedlings. The video below, courtesy of Project Seagrass, shows a Project Seagrass staff member collecting seeds at Porthdinllaen.
The Seagrass Ocean Rescue programme is managed by WWF, in partnership with Project Seagrass, the North Wales Wildlife Trust, Pen Llŷn a’r Sarnau Special Area of Conservation (SAC) and Swansea University. The programme is supported by funders that include the National Lottery Heritage Fund, the Garfield Weston Foundation and the Moondance Foundation. Young people aged 11-16 take part in Its Ocean Rescue Champions programme.
Postcode: LL53 6DB View Location Map
More seagrass information – Project Seagrass website
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