Welsh seas are home to a wide variety of fascinating species and habitats. From extensive sandy beaches, estuaries, rich shallow bays, complex rocky shores and islands, the variety of habitats in Wales supports a wealth of marine species from the enigmatic bottlenose dolphin to colourful anemones.

Many of the marine species in Wales are nationally and internationally important. For example, Cardigan Bay has one of the largest resident populations of bottlenose dolphin in the UK, while Skomer and the Pembrokeshire coast is important for breeding Atlantic grey seals.

The seabird colonies of Skomer, Skokholm, Bardsey and Grassholm are spectacular, supporting puffins, guillemots, razorbills and approximately 45,000 breeding pairs of Manx shearwater Puffinus puffinus - the largest breeding population in the world.

Tide-swept channels are rare in the UK, and the Menai Strait in north Wales is a notable example, having strong tidal currents but sheltered from wave action. The seabed in this high energy environment is colourful and diverse, with filter feeding species including the breadcrumb sponge Halichondria panicea and mermaid’s glove Haliclona oculata and a number of bryozoans, ascidians and hydroids. There is also an abundant population of the large daisy anemone Cereus pedunculatus. Other examples of tide-swept channels are found in south-west Wales, in Milford Haven, Jack Sound, Skomer, and Ramsay Sound.

The striking pink sea fan Eunicella verrucosa is a nationally protected, slow growing cold water coral found at its northern limit in Wales at Skomer Island.

Wales’ seas are also important for shellfish – mussels are grown commercially in the Menai Strait and cockles are collected from intertidal areas around Wales.

Map of Welsh waters 12nm pink and out to midline green

Map of Welsh waters

Welsh inshore waters, within 12 nautical miles of the high-water mark, comprises 43% of Welsh territory and is shown in pink.

The green area represents waters from 12 nautical miles to the midline with Ireland, making up the Welsh European Economic Zone.

Diversity of Welsh marine fauna

The marine environment in Wales is rich - this table indicates the approximate numbers of species in different taxonomic groupings within 12 nautical miles of our coast.

Marine taxon
Number of species
Marine mammals (seals, dolphins, whales, porpoises, otter) 7 have significant, regular and frequent presence in Wales (others sighted occasionally or as dead / live stranded)
Invertebrates (inc. sponges, jellyfish, snails/slugs, crabs, lobsters, barnacles, prawns/shrimps, starfish, sea urchins, sea cucumbers, segmented worms and sea squirts) c2,000 - 3,000
Reptiles (turtles) 1 within normal range (with 5 other species recorded)
Fish (bony and cartilaginous) c250-500
Macroalgae (seaweed) c400
Flowering plants (seagrass) 2 (plus Ruppia spp.)

Marine Conservation in Wales

Numerous pieces of legislation work to protect marine species in Wales.

Marine species and habitats in Wales are primarily safeguarded through the Marine Protected Area (MPA) network, with MPAs covering 69% of Welsh inshore waters. This network ensures that protection of marine habitats and species is achieved at different scales of importance - regional, national and European.

The EU Habitats Directive, transposed into UK law via the Conservation of Habitats and Species Regulations 2017 and the Conservation of Offshore Marine Habitats and Species Regulations 2017, offers protection from direct harm for a number of marine species designated as European Protected Species (EPS). Several marine habitats and species are also protected within Special Areas of Conservation (SACs). Similarly, birds are protected in Special Protection Areas (SPAs) and Ramsar sites.

The Wildlife and Countryside Act 1981 offers protection to marine species, especially marine mammals and turtles, fish and some invertebrates and includes approximately 45 marine species found in Wales. This legislation is also responsible for the designation and protection of Sites of Special Scientific Interest (SSSIs), which contain a wide variety of marine features.

The Marine and Coastal Access Act 2009 (MCAA) is an important piece of legislation for managing Welsh seas. This Act introduced a number of changes, including a revised system of marine management and licensing, including new powers to develop marine plans, changes to the management of marine, migratory and freshwater fisheries, recreational access and importantly marine conservation. MCAA introduced new powers for the Welsh Ministers to designate Marine Conservation Zones (MCZs) in the Welsh inshore region. Skomer is currently Wales’ only MCZ. However, work is currently ongoing to identify further MCZs in Wales which will assist in completing the MPA network in Wales.

The Environment (Wales) Act 2016 - Section 7 – includes lists of species and habitats which are of key significance to biodiversity in Wales and which public bodies have a duty to maintain and enhance. This list currently includes 55 fully marine species, with additional species such as the European otter and Atlantic salmon which spend only part of their life in the marine environment.

There is further information about the protection of specific marine species groups in the relevant sections.

Organisations involved in marine conservation in Wales

Although the Welsh Government has overall responsibility for ensuring Wales’ network of MPAs is effectively managed, the delivery of management is a shared responsibility across a number of organisations. Management Authorities (MAs) are organisations with statutory responsibilities in relation to any type of MPA, or who are significant seabed or coastal land owners. These MAs have formed the MPA Management Steering Group which provides a strategic steer for the MPA network. They have produced the MPA Management Framework which contains a vision and objectives for managing the network.

Natural Resources Wales (NRW) have a statutory and regulatory role in marine conservation. For example, NRW develops marine evidence, advises on site protection and management, produces site condition assessments, delivers marine licencing on behalf of Welsh Ministers, carries out monitoring and reporting and leads on development of the marine protected sites network. NRW are also responsible for other aspects of marine and estuarine environment, such as the management of migratory fish out to 6 nautical miles. NRW are also currently partner in a number of large marine projects.

Environmental NGOs have an important part to pay in marine conservation, education and engagement. The Wildlife Trust – Living Seas Wales is The Wildlife Trusts’ vision for the future of UK’s seas. The project protects Wales' marine wildlife by organising events and activities, monitoring, surveying beaches and undertaking practical conservation activities. The Marine Conservation Society (MCS) is a large UK marine NGO campaigning for better protection of the oceans and are currently leading the ‘Marine Treasures’ project in Wales. Other environmental NGOs include British Trust for Ornithology, WWF, RSPB and other specific groups which focus on species groups (e.g. mammals). European Marine Site Officers contribute significantly to marine conservation in Wales with a site-specific emphasis. There are also a variety of research institutions which contribute to projects and research in Wales.

Records of marine species are fundamental to our understanding of marine species distribution and changes over time. Citizen Science projects such as Seasearch, Shoresearch, marine mammal citizen science projects and other specific campaigns, such as the Great Eggcase Hunt, provide useful data to add to the existing monitoring undertaken by statutory agencies.

There are a number of projects ongoing which aim to restore and manage marine species and habitats which are threatened or declining, which are outlined in the specific marine species sections.

Species in Wales

Amphibians & Reptiles



Terrestrial Mammals



Helping Wildlife

Wildlife Gardening