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The Honolulu Advertiser
Posted on: Saturday, March 31, 2001



Orcas may be feeding on larger cousins

By Jan TenBruggencate
Advertiser Science Writer

The increasing numbers of humpback whales wintering in the Islands each year are likely to attract more pods of orca, or killer whales, like the pod that may have attacked a young humpback off Kaua'i on March 20.

Orca researcher John Ford, a marine mammal biologist with the Vancouver Aquarium, said orcas follow gray whale migrations down the California coast and might readily respond to increased potential prey around Hawai'i by following the humpbacks. Their favorite prey among whales: young calves.

"They are adaptable. They learn. There may well be more frequent sightings of killer whales in those (Hawaiian) waters. They might put them into their routine," said Ford, who has conducted marine mammal studies off both Maui and Hawai'i.

Orcas, glossy black-and-white cetaceans, are the largest members of the dolphin family. Keiko, the star of the "Free Willy" movies, is an orca. The toothed whales can grow to 32 feet in length and weigh up to eight tons.

While sightings are rare in the Hawaiian Islands, they may have been on the rise in the past decade. The National Marine Fisheries Service cites reports of orcas feeding on small whales off Wai'anae in the early 1990s. A boater reported an orca off O'ahu in 1997.

Whale watcher Chris Bane said he has spotted the distinctive orca dorsal fin — sometimes described as a huge, black "sail" — at least once in each of the past five years in the channel between Kaua'i and Ni'ihau.

Ford said that is not necessarily unusual.

"Killer whales are probably second only to humans as the most widespread species on the planet. There is no water where you can be sure you won't find them, although they are most common in temperate and colder waters," he said.

Whale researchers say there are two distinct kinds of orca, although both are in the same species. One is a fish eater and the other a meat eater. Although the terms are not entirely accurate, fish eaters such as the salmon-feeders off Alaska and the herring-feeders off Norway are called resident orcas, while those that eat seals, birds, an occasional swimming deer and even whales are called transient orcas.

Ford said orcas in Hawai'i are more likely to be transients, but may eat more than just mammals.

"I would imagine they might take sharks, like tigers and hammerheads, perhaps monk seals, dolphins and sea turtles," he said.

The concept of orcas attacking humpbacks is intriguing, he said.

"We don't see a lot of attacks on humpbacks (off Canada and Alaska). Yet, a lot of humpbacks do bear a lot of killer whale teeth scars on their tails, which makes us wonder whether there's a level of predation during their migration," Ford said.

Hawai'i's humpback whales migrate each year from the cold waters off Alaska to winter and calve in the warm waters of the Islands.

Bane, who viewed the orca pod feeding off Kaua'i March 20 from his Holoholo Charters tour boat, said one of the first things he and a boatload of whalewatching clients saw was a group of humpbacks behaving oddly.

"There was a cluster of 20 or more humpbacks. It was really freaky, they were packed so closely together," he said. About the same time, the group saw the characteristic angular dorsal fin of a large male killer whale and at least four other orcas, he said.

Whatever feeding activity that took place was happening underwater, but one of the first signs of feeding above the surface was the largest male coming to the surface with "a long, shiny thing in its mouth. I felt it was a tongue," he said.

Later, the male came up with a six-foot chunk of flesh that appeared to be belly meat from a humpback. "I could see the ventral pleats, fat and muscle. The male was feeding the others. They were coming and taking bites of what he had," Bane said.

Orca attacks on humans are virtually unknown, but Ford said he would not take a chance with transient orcas, and would recommend against getting in the water with them.

"Generally, orcas are "inherently cautious" and unlikely to attack something they don't recognize, unlike a shark might be.

"They are far more cognitive types of animals," he said.