Marine Species

In Ireland, there are two groups of mammals that inhabit almost exclusively the marine environment, cetaceans and seals.

Cetaceans account for 48% of all the native species of mammals, both marine and terrestrial, recorded in Ireland and Irish waters are thought to contain important habitats for cetaceans within the northeast Atlantic. To date, 24 species of cetacean, or 28% of species described worldwide, have been recorded in Ireland. Irish cetaceans include six species of baleen whale and eighteen species of toothed whale, including five species of beaked whale. Twenty-two of these have been reported stranded ashore and 20 species observed at sea. Two species (Pygmy sperm whale and Gervais’ beaked whale) are only known from stranded individuals and two species (Northern right whale and White whale/beluga) have only been recorded historically, with neither species occurring in the stranding record so far.

Ireland also has two species of seals, the Common Seal (or Harbour Seal) and the Grey Seal. Whilst both species haul out on land for key stages of their life history, the majority of their time is spent in the marine environment.

In Ireland, the 1992 EC Habitats Directive as transposed by the European Communities (Birds and Natural Habitats) Regulations 2011 (S.I. No. 477 of 2011) requires that both seal species and all cetaceans occurring in Ireland are maintained at favourable conservation status. Under Article 12 of the Directive, all cetaceans should receive strict protection within the Exclusive Economic Zone. Under Article 4 of the Directive, Special Areas of Conservation (SACs) must be proposed for the following species:

Bottlenose Dolphin


Harbour Porpoise


Common Seal


Grey Seal


Bottlenose Dolphin II Grey Seal Pup Stage 3

Under the Wildlife Acts 1976 to 2018, all cetaceans and seals are protected species listed on the 5th Schedule. Under this Act, Natural Heritage Areas (NHAs) may be established to protect habitats or species. Whilst some terrestrial and coastal NHAs may encompass adjacent marine areas, no NHAs have been established for marine mammals to date.

Under the OSPAR Convention to Protect the Marine Environment of the North East Atlantic, Ireland committed to establishing marine protected areas to protect biodiversity (i.e., OSPAR MPAs). No legislation is currently used in Ireland to legally underpin protected areas established to fulfil commitments under international conventions. Therefore, since the creation of OSPAR MPAs would not afford any legal protection to the relevant areas on their own, Ireland established a number of its SACs as OSPAR MPAs. Two of these, Roaringwater Bay & Islands MPA and Blasket Islands MPA, were submitted for the Harbour Porpoise.

The protection afforded to marine mammals in Ireland is summarised below:

Harbour Porpoise Annex II of EC Habitats Directive
Annex IV of EC Habitats Directive
Protected species of Wildlife (Amendment) Act
OSPAR List of Threatened and Declining Species and Habitats
Bottlenose Dolphin Annex II of EC Habitats Directive
Annex IV of EC Habitats Directive
Protected species of Wildlife (Amendment) Act
All Cetacea Annex IV of EC Habitats Directive
Protected species of Wildlife (Amendment) Act
Grey Seal/Harbour Seal Annex II of EC Habitats Directive
Protected species of Wildlife (Amendment) Act


Common Dolphin Harbour Seal
Common Dolphin (Photo: IWDG) Common Seal (Photo: NPWS)