Two species of seal occur commonly in the Celtic Seas: grey seal Halichoerus grypus and harbour seal Phoca vitulina.
Thirteen
cetacean species occur commonly or are resident in the Celtic Seas: minke whale Balaenoptera acutorostrata, fin whale
Balaenoptera physalus, harbour porpoise, short-beaked common dolphin Delphinus delphis, white-beaked dolphin
Lagenorhynchus albirostris, Atlantic white-sided dolphin Lagenorhynchus acutus, sperm whale Physeter macrocephalus, longfinned
pilot whale Globicephala melas, northern bottlenose whale Hyperoodon ampullatus, Sowerby's beaked whale
Mesoplodon bidens, killer whale, Risso’s dolphin Grampus griseus, and bottlenose dolphin.
The abundance of grey seals in the
Celtic Seas ecoregion is stable, and there is little information on the overall trends of harbour seals and of cetaceans.
Marine mammals that are threatened or declining in the Celtic Seas acording to OSPAR:
Balaenoptera musculus Blue whale
Eubalaena glacialis Northern right whale
Phocoena phocoena Harbour porpoise
