Fetlar to Haroldswick NCMPA (Nature Conservation MPA) sits where the North Sea and the Atlantic Ocean meet, creating a turbulent mixing of waters and strong tides. The complex mosaic of islands, open coastline, high energy waters and more sheltered bays and voes results in a wide range of habitats that support a remarkably diverse array of animal and plants, particularly maerl beds, kelp and seaweed communities, shallow tide- swept sands with burrowing bivalves, and horse mussels beds. The towering cliffs are also home to one of Scotland‟s largest colonies of breeding black guillemots, (also known as tysties), which forage over the rich and diverse seabed habitats.
The NCMPA overlaps the Fetlar Special Protection Area (SPA) for various breeding birds including Arctic tern, Arctic skua and fulmar, with the inclusion of the large (greater than 2000 individuals) breeding colony of black guillemots.
The clear shallow waters in the inner part of the NCMPA are ideal for maerl, a hard, free-living nodular red seaweed that carpets the seabed in places. Maerl beds provide shelter and protection to a wide range of other animals and plants including some important commercial fish species. In some of the narrows between the islands tide swept coarse gravelly sands support an abundance of bivalves such as tellins and surf clams. Horse mussel beds are found in the deeper tide-swept areas supporting the dense brittlestar communities that form mesmerising seas of waving arms, together with starfish, sea urchins, feather stars, and dead man's fingers.