Orcas leave a reminder of nature's brutal reality

By SIMON COLLINS

The pod of orcas made a romantic picture as they swam out of the Waitemata Harbour on Friday, their tails framed by the silhouette of Rangitoto Island.

But yesterday the cost of their visit became clear when Department of Conservation staff buried a 12m Bryde's whale, apparently killed for its 2m tongue, which is an orca delicacy.

A mutilated bottlenose dolphin found dead on Motutapu Island on Thursday is believed to have been another victim. It has been sent to a specialist pathologist at Massey University.

The 18-tonne Bryde's whale, slightly bigger than its orca attackers, was the first of its species to be documented as an orca victim in New Zealand, although orca scientist Dr Ingrid Visser said other cases had been reported overseas.

"You name it, I have records of them hunting them - sperm whales, humpbacks, southern right whales in New Zealand, and overseas they have records of them hunting just about every species, including the blue whale, which is the largest animal that ever lived," she said.

"They hunt in a pack."

The Bryde's whale was spotted floating near Tiritiri Matangi on Friday with its intestines hanging out of a gaping wound.

But it was not until it was towed to shore north of Long Bay yesterday that experts were able to confirm that its tongue had been torn out and its body was marked with tooth bites up to 30cm wide.

Auckland University Professor Scott Baker said the tongue in a baleen whale was huge, as the mouth was typically a third of the length of the animal.

"The Bryde's whales are lungers," he said. "They don't filter prey, they target dense concentrations of small fish and lunge up into them and engulf them.

"They expand the ventral quilted part which runs from the tip of the mouth normally for two-thirds of the length of the animal. That fills up with water to perhaps a third of the total weight of the whale.

"Then they use the tongue to push the water out through the baleen [sieve]."

Early last century, orcas at Eden in New South Wales regularly helped whalers to round up other whales to be harpooned. The whalers rewarded the orcas by throwing them the victims' tongues.

Doctoral student Nicky Wiseman, who is writing her thesis on Bryde's whales and helped to dissect the latest victim, said they usually caught fish in teams with gannets and dolphins. "The dolphins round up the fish, the gannets dive in, and the Bryde's whales come through and take a big gulp."

Conservation Department ranger Karl McLeod, who led the dissecting team, said the orca victim was the sixth Bryde's whale he had buried in the Hauraki Gulf in the past five years. Two were hit by boats and the other three died of natural causes.

Meanwhile, Dr Visser said the pod of 18 orcas which swam into Auckland on Friday was spotted yesterday at Kennedys Bay near the tip of the Coromandel Peninsula.

Dr Visser said she regularly swam with orcas and had never seen any signs of aggression towards her. Her hotline is 0800 SEE ORCA (0800 733-6722).