Wonderful Welsh marine wildlife

The seas around the Welsh coastline are teeming with a vast array of different species. Here are some you may be lucky enough to see:

Atlantic grey seals – 40% of the world’s population of Atlantic grey seals can be found in the UK. The largest colonies in the Irish Sea are found around the Welsh coastline, particularly on Skomer and Ramsey Island. The seals give birth during the autumn, which is a great time to see pups on these island reserves.

Honeycomb reef worm – Living in the tubes they build from sand and fragments of shell, colonies of these worms resemble a honeycomb pattern and form life supporting reefs which are often exposed at low tide. Be careful not to damage the fragile homes of these wonderful worms.

Bottlenose dolphin – These playful and sociable creatures can grow up to 4 meters long, and can often be seen leaping out of the water, generally in groups of 3-10 individuals. There are believed to be approximately 200 bottlenose dolphins in Cardigan Bay, which is one of only two semi-resident bottlenose dolphin populations in the whole of the UK.

Sea anemones – Related to jellyfish, sea anemones spend most of their lives stuck to rocks, where they use specialised tentacles covered in stinging barbs to capture small creatures like shrimps. Snakelock anemones are often seen in rock pools around Wales, and have around 200 long tentacles.

Basking sharks – The basking shark is the second largest fish in the world, reaching 8-10 meters in length. Despite its huge size, it only feeds on tiny plankton. Summer is the best time to see these giants, when they migrate through the waters around Wales.

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The magestic basking shark filtering plankton from the water

Image courtesy of Andrew Pearson

Jellyfish – A common sight washed up on the beach, lots of different types of jellyfish can be found in Welsh waters, with names such as the moon, compass, and barrel jellyfish. These species provide an important food source for many marine animals, and are even responsible for attracting species such as the leatherback turtle to Welsh waters!

Harbour porpoise – Harbour porpoises are often mistaken for bottlenose dolphins, when in fact they are actually much smaller. They exist along the majority of the Welsh coastline and are most commonly seen from August to November. When sea-watching, use diving gannets as a highly visible clue to finding porpoise, as they often feed on the same fish.

Kelp beds – Kelp forests are incredibly important habitats which are diverse and species rich. They provide a refuge and a variety of habitats for many marine species in a similar way to forests on land. You may find fronds of kelp or the holdfast which attaches them to the seafloor washed up on the beach after a storm or rough weather.

Manx shearwater – This dark coloured bird spends most of its life at sea, skimming the tips of waves in search of food. Over 45% of the global population breed on a handful of islands in Welsh waters. In the summer months, hundreds of thousands of these graceful gliders return to Wales, travelling over 7,000 miles from the coast of South America where they spend the winter

Crabs – Probably the most common crab on the seashore in Wales is the shore crab, which you might find under stones or hidden amongst pieces of seaweed in rock pools. However, you may also find the edible crab which can live up to 20 years, or a velvet swimming crab with its distinctive bright red eyes.

Common mussels – When the tide is out, you may find mussels in crevices or exposed rock between the high and low watermark. This species is commercially farmed in Wales, particularly in Conwy Bay and the Menai Strait. Mussels play an important role in filtering seawater, and are often used as an indicator species to monitor the health of coastal environments.

Auks - Razorbills, guillemots and the more familiar puffins are all members of the auk family; they spend most of their lives at sea and only come to land to have their young. The waters around the Welsh coast are particularly important to them as they breed on the many islands and cliffs around our shores. May to July is the best time to see puffins on Skomer Island.

For information on more of the wildlife present around the Welsh coastline and where you might see it, visit our interactive map.