Marine Life
Surrounded by over 4,000 km² of Irish Sea, the Isle of Man's marine environment is as rich as its land. From Basking Sharks and seal colonies to ancient kelp forests and seagrass meadows — the Manx territorial sea is a biodiversity hotspot.
Species Distribution Map
Search marine species and see where they've been recorded across IoM waters.
Explore species →Marine & Maritime Map
Interactive EMODnet map showing MPAs, lighthouses, shipwrecks, and subsea cables.
Open map →Iconic Marine Species
Basking Shark
Cetorhinus maximus
The world's second-largest fish and the Isle of Man is a global hotspot. Peak sightings May to August off the west coast, with individuals up to 12 metres long filter-feeding on plankton. Protected under Manx law since 1990.
Grey Seal
Halichoerus grypus
A large breeding colony at the Calf of Man, with pupping from September to November. Approximately 500 breeding females haul out on the rocky shores. Bulls can weigh over 300 kg.
Harbour Porpoise
Phocoena phocoena
The most common cetacean in Manx waters, present year-round. Often seen from harbours and headlands on calm days. Smaller than dolphins, with a blunt rounded snout and triangular dorsal fin.
Bottlenose Dolphin
Tursiops truncatus
Pods regularly seen from Douglas Head, Peel breakwater, and from the ferry. The Irish Sea population is an important group, with individuals photo-identified across the region.
Manx Shearwater
Puffinus puffinus
Named after the Isle of Man, where it was first scientifically described. Returns to breeding burrows on the Calf of Man from May to September, visiting only after dark. Migrates to South American waters in winter.
Leach's Petrel
Hydrobates leucorhous
A rare passage migrant best seen from Point of Ayre during autumn gales. These small, ocean-going seabirds spend most of their lives far out at sea and are only driven close to land by strong westerly storms.
Marine Protected Areas
The Isle of Man has designated 31 Marine Nature Reserves and other protected zones managed by DEFA (Department of Environment, Food and Agriculture). Key sites include:
Ramsey Bay
Kelp forests, horse mussel beds, and important nursery habitat for commercial fish species.
Douglas Bay
Nursery ground for juvenile fish. Sheltered bay with sandy and rocky habitats.
Port Erin Bay
Historically one of the most studied bays in the world — home to the IoM Marine Biological Station (1892-2006). Rich intertidal and subtidal ecology.
Langness
Reef habitats with diverse communities of sponges, anemones, and bryozoans on rocky substrate.
Calf and Wart Bank
Offshore gravel banks supporting rich benthic communities and important spawning grounds.
Niarbyl Bay
Geological interest site where the Iapetus Suture — the ancient join of two continents — is visible.
Baie ny Carrickey
Seagrass beds providing critical carbon sequestration and nursery habitat for fish and invertebrates.
Little Ness
Intertidal reef with wave-exposed rocky shore communities and rich rockpool ecology.
West Coast
Pelagic zone important for Basking Sharks, cetaceans, and seabird foraging.
Queenie Corner
Queen scallop (Aequipecten opercularis) grounds — the Manx queenie is an iconic local fishery.
🏛️ Port Erin Marine Biological Station
The Port Erin Marine Laboratory operated from 1892 to 2006 under the University of Liverpool. For over a century it was one of the most important marine research stations in the British Isles.
Research here contributed to our understanding of Irish Sea ecology, fisheries science, plankton dynamics, and marine conservation. The station's long-term datasets remain invaluable for climate change studies.
More from Biosphere
Data sources: DEFA Marine · Manx Wildlife Trust · Manx Basking Shark Watch