Cli­mate change mak­ing nar­whal ner­vous

The Hamilton Spectator - - CANADA & WORLD - BOB WE­BER

A study has con­cluded that the in­creased pres­ence of killer whales in Arc­tic wa­ters is in­tim­i­dat­ing nar­whal into dras­ti­cally chang­ing their be­hav­iour.

It’s an­other symp­tom of how cli­mate change is re­mak­ing the del­i­cate north­ern en­vi­ron­ment.

“Just hav­ing (killer whales) around is ter­ror­iz­ing their prey and caus­ing them a lot of dif­fi­cul­ties,” said Steve Fer­gu­son of the Depart­ment of Fish­eries and Oceans, a coau­thor of the pa­per.

“They’re hav­ing to add this on top of all their other prob­lems.”

More than 5,000 nar­whal, which grow a sin­gle long tusk from the front of their head, are thought to sum­mer in Ad­mi­ralty In­let on the north coast of Baf­fin Is­land.

Ex­ten­sive year-round sea ice once lim­ited the num­ber of killer whales in those wa­ters. The de­cline of that ice due to global warm­ing means killer whales ar­rive ear­lier, leave later, and are greater in num­ber.

Fer­gu­son and his col­leagues used teleme­try to track a pod of killer whales and a num­ber of nar­whal over an 18-day pe­riod in the vast in­let, which is 300 kilo­me­tres long and 50 kilo­me­tres wide.

When killer whales weren’t around, the nar­whal went af­ter abun­dant shoals of prey fish be­tween four and 10 kilo­me­tres from shore. But when the or­cas were any­where in the in­let, nar­whal cow­ered within 500 me­tres of shore.

“I think the nar­whal are scared to death,” said Fer­gu­son. “Watch­ing your brother or sis­ter or mother get killed and eaten by a killer whale would cause a lit­tle post-trau­matic stress in most of us.”

Fer­gu­son has a the­ory on how the nar­whal know.

“Killer whales are quiet,” he said. “They al­most don’t com­mu­ni­cate while they’re hunt­ing.

“But once they make a kill, they tend to cel­e­brate and make a lot of noise. And quite likely, in the chase, the nar­whal are able to com­mu­ni­cate and some­how this gets passed on down through the dif­fer­ent groups.”

The pre­da­tion drives the nar­whal from their rich­est feed­ing grounds.

The killer whales also ar­rive at a time when the nar­whal are try­ing to raise young. Part of the rea­son nar­whal gather in Ad­mi­ralty In­let is the pro­tec­tion it once of­fered.

Hug­ging the shore also ex­poses them to Inuit hun­ters for whom nar­whal is a val­ued food.

“The hun­ters love it,” said Fer­gu­son.

Those fac­tors add stress to an al­ready dif­fi­cult en­vi­ron­ment.

KRISTIN LAIDRE, THE CANA­DIAN PRESS

More than 5,000 nar­whal, which grow a sin­gle long tusk from their head, are thought to sum­mer in Ad­mi­ralty In­let on the north coast of Baf­fin Is­land.

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