Of the 24 cetacean species reported in Ireland, ten species (Harbour porpoise, Atlantic white-sided dolphin, White-beaked dolphin, Bottlenose dolphin, Common dolphin, Risso’s dolphin, Killer whale, Northern bottlenose whale, Long-finned pilot whale and Sperm whale) are thought to be present year-round while it is possible that Cuvier’s beaked whale and Sowerby’s beaked whale are also resident in deep-water gullies off the western seaboard. Six species (Minke whale, Blue whale, Fin whale, Sei whale, Humpback whale and Striped dolphin) are thought to be seasonally present and six species (Northern right whale, White whale or beluga, False killer whale, Gervais’ beaked whale, True’s beaked whale and Pygmy sperm whale) are thus far classified as rarely occurring or vagrant.

Irish waters contain an array of potential marine habitats for cetaceans, including shallow continental shelf waters (<200 m deep), those overlying the continental slope, deep ocean basins off the western seaboard (c. 2,500-4000 m depth), gullies and canyons along the continental slope and shallow offshore banks (<200 m depth). Shallow continental shelf waters extend up to 200 km from the coast and include the Irish Sea. The edge of the continental shelf stretches up to 800 km along the Atlantic seaboard and approaches to within c. 60-100 km from the northwest and southwest coasts respectively. All habitats are extensive in area with approximately 297,000 km2 of continental shelf waters, 170,000 km2 of deep waters, 115,000 km2 of waters overlying the continental slope and 37,500 km2 covering offshore banks. It is possible from the intensive survey effort at sea conducted in Ireland in the last decade to identify the likely Habitat of individual cetacean species within Irish waters (PDF icon [360KB]).

In 2007 the European Court of Justice ruled that Ireland had failed to fulfil its obligations in relation to inter alia Article 12 of the Habitats Directive (Case C-183/05). The Conservation Plan for Irish Cetaceans (PDF icon [5MB]) was prepared as part of Ireland’s response to this judgement and was finalised in December 2009 following extensive statutory and public consultation. This Plan provides comprehensive information concerning the ecology of all cetacean species occurring in Ireland. It identifies the primary pressures and the administrative and scientific gaps that pose a threat to their protection, and identifies clear measures required to ensure such threats are addressed. The Plan consists of five main programmes of measures presented in a Delivery Grid (updated May 2015) against which progress can be clearly measured.

Details of a National Cetacean Protection Strategy (PDF icon [53KB]) have also been elaborated. This three-pillared approach underpinned by the Conservation Plan for Cetaceans in Irish Waters focuses on (i) designating and monitoring SACs, (ii) ensuring general regulatory and administrative functions are sufficiently rigorous, and (iii) pursuing an integrated strategy for general surveillance of cetaceans.