Skomer Marine Nature Reserve is one of only two such sites in Britain. It is located off the coast of Pembrokeshire.
The reserve completely surrounds the islands of Skomer and Middleholm and encompasses the mainland coastline around the end of the Marloes peninsula, including the small bay of Martin's Haven.
The sea bed and rocky shelves of the island are teeming with life. Common eelgrass, Zostera marina, one of the very few plants that flower underwater, grows on beds of sand and gravel in sheltered waters and its long, grass-like leaves form underwater lawns that provide food and shelter for other plants and animals. Species of lobsters, crabs and other crustaceans abound, and grey seals give birth on the coast in October and November.