Thursday 19 July 2018

'Baffling' rise in beached whales

GENTLE GIANTS: Local woman Nod Martin and a beached whale at Culleenamore, Co Sligo, in the shadow of Knocknarea
GENTLE GIANTS: Local woman Nod Martin and a beached whale at Culleenamore, Co Sligo, in the shadow of Knocknarea

JEROME REILLY

WHALE and dolphin watchers are puzzled and alarmed at an unprecedented spike in the number of deep-water species being stranded and found dead on Irish beaches in the last 14 weeks.

There has been a similar worrying increase in the number of strandings on UK coasts -- especially in Scotland -- according to Mick O'Connell of the Irish Whale and Dolphin Group (IWDG).

The species involved include pilot whales (Globicephala melas) Cuvier's beaked whales (Ziphius cavirostris), and Sowerby's beaked whales (Mesoplodon bidens).

The IWDG has received an unusually high number of reports of strandings since the beginning of the year mostly on western and northern coasts.

Between January 1 and April 17, the organisation received reports of 12 separate pilot whale strandings around the Irish coastline including Cork, Kerry, Sligo, Mayo and Donegal.

It's a shockingly high figure compared with an average over the last four years of 2.6 separate pilot whale strandings for the same three-and-a- half month period of each year.

"We have also received reports of five strandings of either Cuvier's beaked whales (2) or unidentified beaked whales (3) in Co Cork, Streedagh near Sligo town, Fanad in Donegal and at Sherkin Island, Co Cork.

The average number of stranding incidents involving these beaked whale species in the years 2003 to 2007 was just 0.6 during the same period annually.

"It's certainly worrying and we are monitoring the situation," Mr O'Connell told the Sunday Independent.

Beaked whales are mysterious creatures of the deep ocean and feed, it is believed, on or near the sea floor.

They have the ability to dive for extraordinarily long periods and to great depths of more than a mile, making them the deepest diving air-breathing animals known.

Beaked whales are found in all oceans, but most species rarely venture into the relatively shallow water of the continental shelves. They feed primarily on deep water squid, but also on fish and sometimes on crustaceans.

Because they prefer the deep waters, they are very difficult to observe and little is known of most species.

"In effect, what we are seeing so far this year is that beaked whale strandings are running at about 8.3 times average, and pilot whale strandings are running at about 4.6 times the average," Mick O'Connell has reported on the IWDG website.

"Since February, the west coast of Scotland has also seen a significant increase in strandings of these species with a minimum of 11 Cuvier's beaked whales, three Sowerby's beaked whales and 10 pilot whales recorded so far.

"In the majority of cases, the animals died at sea and washed ashore in an advanced state of decomposition, which raises the question of how many others stranded in inaccessible locations or did not wash ashore at all," he said.

In previous incidents involving mass strandings of beaked whales, concerns have been raised over the effects of naval sonar during military exercises. "At present, we have no evidence of the cause of death of these cetaceans. It's curious that pilot whales are also involved," he said.

The IWDG have been in contact with the Woods Hole Oceanographic Institution in the US as well as the Whale and Dolphin Conservation Society (UK) and the Sea Mammal Research Unit at the University of St Andrews, Scotland, to determine if military or seismic operations were being carried out during the first few months of this year.

One theory is that beaked whales are vulnerable to new ultra-loud anti-submarine sonar, which may force them to surface too quickly and then die from the bends. However, the large number of Pilot whales stranded may suggest there is another reason for the increase in dead cetaceans washed up on our shores.

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