1 In Marine Biodiversity in Ireland and adjacent waters. 2001. Edited by Nunn J.D. Ulster Museum, Belfast. Pages 115-120.

Irish waters are some of the most important in Europe for a wide range of cetacean (whales, dolphins and porpoise) species. Historically whales were hunted in Ireland (Fairley, 1981) but now they are all protected under a wide range of national and EU legislation. However due to a lack of information on the basic ecology and habitat requirements of most species, this important element of Irelands ’ fauna is rarely acknowledged in nature conservation and management in Ireland. This paper reviews the biodiversity of marine mammals in Irish waters and briefly discusses issues which may impact on this biodiversity, including actions that will improve our ability to protect the great abundance and diversity of cetaceans around the island of Ireland. Diversity of cetaceans around Ireland To date 24 cetacean species have been recorded in Irish waters. Twenty-one of these have been reported washed up or stranded (Berrow and Rogan, 1997) and three species have been observed (Evans, 1980). One species, the false killer whale Pseudorca crassidens, was only positively confirmed as occurring in Irish waters this summer (O. Kiely, pers. comm.) although bones suspected to be from this species have been reported from Counties Mayo and Kerry (Berrow and Rogan, 1997). The biodiversity of marine mammals in Irish waters compares very favourably with terrestrial mammals. Table