International research involving Irish scientists on the migratory movements of humpback whales suggests that they are frequenting areas where they had previously been hunted by man.
Two humpback whales identified by the Irish Whale and Dolphin Group (IWDG) in Irish waters have now been traced to Norway and Iceland, as part of a pattern of movements between the Cape Verde islands, the Netherlands and Ireland.
One of the whales, known as HBIRL7, which was identified by IWDG researcher Dr Conor Ryan off the Cork coast in September 2007, has been traced to the Netherlands and up the North Sea to Norway, while a second, spotted off Iceland, has been confirmed as another Irish visitor.
Humpbacks, which are attracted to Irish waters by sprat and herring, were hunted by Norwegian-owned whaling stations in Co Mayo at the turn of the last century.
It is estimated that there are at least 1,000 humpbacks in north Atlantic breeding grounds, off the West Indies, and some 28 individuals, including the Cork repeat visitor Boomerang, have been recorded here since 1999.
One of these 28, known as HBIRL7 or Dutchy , was a juvenile when recorded by Dr Ryan in 2007. Two months later, it was photographed off the Netherlands.
Five years later, north Norwegian plankton ecologist Fredrik Broms photographed humpback "flukes" or tails near Tromsø in north Norway, some 350km inside the Arctic Circle.
Dr Broms had set up the North Norwegian Humpback Whale Catalogue after he noticed “unprecedented numbers” of humpback whales arriving in his local area from late 2010.
After many months of research, he confirmed that this particular humpback’s fluke was that of Dutchy, who had been feeding off Cork in 2007.
Now a second visitor to these waters has been identified off Iceland. The mammal, named HBIRL25 when photographed by Nick Massett near Kerry's Blasket islands last September, was recently recorded by Icelandic whale watching guide Christian Schmidt off Husavik.
Pádraig Whooley of the IWDG says it is “very exciting to know that the mammals are completing such extensive round trips through some of the world’s busiest shipping lanes, crossing the Dover Straits”.
The risks that the humpbacks run from ship strikes “cannot be overstated”, he says.
“These mammals are not only feeding again in the higher latitudes where previously hunted, but also in places like the Irish Sea,” he said.
“The missing link for us is where most of them were actually born.”
