A special survey is to be undertaken on the world-famous group of bottlenose dolphins in the lower Shannon estuary, which it is now believed, may have inhabited the area for centuries.
The Government's heritage department is seeking a count of the mammals as part of the designation of the area as a special area of conservation - the only one of its kind in the country.
The dolphins are constantly seen by passengers on the Tarbet-Killimer ferry. It is estimated that they attract up to 20,000 tourists.
The count will involve identifying the dolphins by transient markings such as bites or scrapes and permanent identifying marks such as nicks on their dorsal fins.
Dr Simon Berrow of the Shannon Dolphin and Wildlife Foundation said that he estimated there were about 120 to 140 bottlenose dolphins living permanently in the estuary. The fact that the dolphins lived there permanently was only scientifically established in the early 1990s. However, references back in history indicate that they have been there for generations and may even have been residents as far back as the sixth century.
Dr Berrow said Co Clare-born St Senan, who established a monastery on Scattery Island, described what might have been the ancestors of the present dolphins. Supposedly before St Senan arrived, a legendary monster called "The Cathach" inhabited the island, terrorising local people. Legend has it that when he arrived on the island the austere saint faced the monster and ordered it, in the name of the Trinity, to depart from the island. The Cathach was supposed to have obeyed immediately. The sea serpent "neither stopped nor stayed" until it reached the waters of Doolough Lake . "There is a description of this monster and the smoke from the fire of its belly that sound just like a dolphin's blow," Dr Berrow said.