Rise in stranding of sperm whales on Irish beaches

Best known for their depiction in the Herman Melville classic Moby Dick , sperm whales are the most celebrated "stranders" and…

Best known for their depiction in the Herman Melville classic Moby Dick, sperm whales are the most celebrated "stranders" and are beaching in greater numbers on the Irish coastline.

Dr Simon Berrow, Irish Whale and Dolphin Group co-ordinator, said male sperm whales appeared to be particularly prone to running ashore accidentally, particularly in the north-west.

One of the last such strandings on this coast was on Tory island, Co Donegal, he said.

The jury is still out on the precise cause of whale strandings, but theories include a failure of their echo-location systems, pursuit of prey or pursuit by predators, magnetic anomalies and the impact of military activity and offshore mineral exploration.

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Sperm whales are only occasionally seen, but are known to frequent these waters close to the Continental Shelf and also around the Rockall Trough area.

Slightly larger than humpbacks, they are the largest toothed whales, are known for their blunt foreheads - which are actually noses - and angled spouts. They can grow to 20 metres in length.

Feeding mainly on squid, they are the largest meat-eaters on earth and were the first cetaceans (whales and dolphins) to be hunted by man.

Behind their "titanic" noses, containing vast reservoirs of oil, are massive brains which can weigh up to seven times that of a human brain. They can dive to depths of 8km, can stay underwater for up to an hour and they use their echo-location systems to hunt prey.

Dr Berrow said a recent study of strandings in Britain and Ireland had suggested that the rise in beachings of the species could be due to a combination of better record-keeping by both scientists and whale and dolphin enthusiasts, but also the impact of military and mineral exploration activity where blasting was employed.

The study led by John Gould, which was published in the Canadian Field Naturalist in 2002, noted a 9 per cent rise in such sperm whale strandings in Ireland and an 18 per cent increase in Scotland.

The Scottish locations were close to areas of offshore oil activity.

The Irish Whale and Dolphin Group has made representations to the Department of Marine and Natural Resources on the impact of such offshore activity here, given that Irish waters were declared Europe's first whale and dolphin sanctuary by the late former taoiseach Charles J Haughey.