Canada: Transient orcas kill lone minke whale

17th Oct 2002 Story:

Transient orcas kill lone minke whale

Saltspring Island residents witness attack by killer whales

Four members of a transient killer whale pod hunted and killed a lone minke whale in front of about 200 Saltspring Island spectators Tuesday afternoon.

It was the first time that scientists had ever witnessed killer whales killing a minke.

"We've heard of it happening, and we'd read about it in the literature, but we'd never seen it ourselves," said John Ford, a marine mammal scientist with the department of fisheries and ocean's Pacific Biological Station in Nanaimo.

"It's something we've never seen in over 25 years of studying killer whales."

In addition to watching the kill, Ford and other scientists recorded the sounds the killer whales made both during the hunt and while eating the minke's flesh.

Ford says spectators caught their first glimpse of the hunt about 10:15 Tuesday morning when the four orcas herded the minke into Ganges Harbour.

Minkes, which can grow to be 10 metres in length, are the smallest of the world's great whales. Only a few are seen regularly in this part of the world.

Ford doesn't know how long the hunted minke was, but said it was driven into shallow water by the four orcas, which then tried to drown it.

The minke managed to escape about 2:15 p.m., he said, but was so weak from loss of blood, that the orcas were able to finish the kill 45 minutes later.

"They're clearly very excited," he said Tuesday afternoon as he watched the orcas feed on the minke's carcass. "It's been a very good day for them."

Ford says about 225 so-called transient killer whales have been identified along the B.C. coast. That's compared to about 300 so-called resident whales.

The names are misnomers born of a previous and erroneous belief that resident orcas don't stray far from Vancouver Island, while transient whales cover a much larger range.

Now it is understood that both populations of whales travel great distances, though how far and where is not known.

What is known, Ford said, is that two distinct populations exist and they don't mix. Also, while resident whales consume large numbers of coastal salmon, transient whales live on an apparently exclusive diet of marine mammals, including seals, sea lions, porpoises and baleen whales.

The reasons for the differences in diet are not known, though Ford says he believes them to be cultural rather than physiological.

He said by observing Tuesday's kill, scientists can add to their knowledge of transient orcas.

"It's something that happens, but it's something we just don't see. We know these animals do take minkes, but being able to witness it is interesting for us and an unusual opportunity."