Scientists tag killer whales in Antarctica in hopes of learning their secrets

By KATE CHENEY DAVIDSON

Anchorage Daily News

Published: July 16, 2006

With heart pounding and sweat pouring into his heavy survival suit, marine biologist Russ Andrews dropped to his knees and took aim. His target: the fast-moving dorsal fin of a killer whale as it swam up an icy lead. He pulled the trigger of his modified air gun and held his breath. Success! The barbed tag landed securely on the black triangle and broke free of its weighted line.

For Andrews, a scientist at the Alaska SeaLife Center in Seward and a researcher for the University of Alaska Fairbanks, an opportunity to visit Antarctica to tag killer whales was a dream come true. In January, Andrews got his chance when he joined a team of researchers from the National Marine Fisheries Service for a monthlong study of killer whales (also known as orcas), one of the most recognizable of marine mammals and one of the least understood.

"It's such a special place," Andrews says of their research area near McMurdo Station on the southern Ross Sea. "To be a foot away from a killer whale ... I could have patted it on the head like it was Sea World."

To get close enough to tag whales, Andrews and his colleagues used a helicopter to locate them swimming in narrow, open leads in the pack ice. Once a sighting was made, the helicopter pilot would fly ahead of the swimming mammals and land so the scientists could set up (see a video of Andrews in action at www.adn.com/life).

Researchers doubt that the whales feel much since the dorsal fin has few nerve endings, but the technology is still new. Andrews has quickly become an expert from his work tagging marine mammals in Alaska waters.

Together, the team tagged 10 whales with electronic tracking devices that, thanks to an array of weather satellites operated by the National Oceanic and Atmospheric Administration, will help scientists understand more about these mysterious animals. To date, relatively little is known about the feeding habits and migration patterns of orcas, especially those in remote areas like the Aleutians and Antarctica.

The advantage of studying killer whales in Antarctica, Andrews says, is the unparalleled access to them provided by long leads of open water in the pack ice. Around McMurdo, researchers found plenty of killer whales taking advantage of the wide leads opened by icebreakers so supply ships could reach the station.

Normally, killer whales must carefully weave through pack ice, poking their heads above the water in search of breathing holes, a practice called "spyhopping." By comparison, Andrews says, tagging killer whales in Alaska is trickier.

"In Alaska we struggle to get close enough to the killer whales. You need to be about 13 to 15 feet away in order to tag them," Andrews says.

The researchers, led by Bob Pitman, a NOAA fisheries scientist, hope to quell a controversy that's been brewing in marine biology circles for decades: whether there are more than one species of killer whale in Antarctica. In the 1980s, two reports by Russian researchers gave compelling evidence that there are at least two species of killer whales off Antarctica -- one that lives in the pack ice and feeds mainly on fish, and a larger type that eats marine mammals and stays mostly in open water -- but their research was deemed scientifically inconclusive without physical specimens.

Pitman was intrigued by the Russians' findings and began conducting his own research in Antarctica six years ago. To his surprise, he identified what looks to be a third type of killer whale around the Antarctic Peninsula. These orcas also patrol the ice pack, but unlike those found deep in the ice around McMurdo, they appear to feed mainly on seals and have different markings. Pitman says more research is needed before the different types can be declared separate species, but the evidence is slowly piling up.

Recent advances in technology are helping. Satellite tagging, tissue sampling and computer modeling are helping to close the knowledge gap about killer whales all over the world, researchers say.

John Durban, a marine biologist with the National Marine Mammal Laboratory, says tagging is especially useful for determining where these mysterious animals go and when.

"Tagging gives us increased resolution on what the animals are doing, especially in winter and at night. It can tell us how they are eating and where they are eating."

Knowing this information is key, say Durban and Andrews, because killer whales have a large impact on whatever ecosystem they're in, and whereas a lot of information is known about certain groups of orcas living in near coastal waters, the groups farther offshore remain a mystery.

"Killer whales are long-lived animals," Durban says, "so the 30 years we've been studying them is really only a generation. We still don't know how these populations change over time."

Andrews and his colleagues are trying to change that one tag at a time. After the Antarctica tagging expedition, one tag stayed on a whale 65 days and provided the researchers with invaluable data. One of the biggest obstacles in getting the tags to stick, Andrews says, is the whales' slippery skin and the aggressive way the animals play and hunt.

Pitman and his team hope to return to Antarctica in 2008 to tag more orcas and get even better results. The batteries can theoretically last a year, but scientists would be happy with six months, which is one migratory cycle.

In some ways, Pitman says, killer whales stand as a reminder of how much we have yet to learn about the ocean's denizens.

"I think it's very telling that killer whales are some of the most recognizable and researched animals we have, yet we don't even know how many species there are."

Daily News reporter Kate Cheney Davidson can be reached at kdavidson@adn.com.

_____________________________________

Whale drama unfolds in Aleutians

Cruising off Unimak Island in the Aleutians last May, marine biologists Russ Andrews and John Durban witnessed a breathtaking event.

The scientists were looking for killer whales to tag when suddenly they came upon three killer whales attacking a juvenile gray whale. Although the area is a known hunting ground for killer whales looking to intercept migrating gray whales, to actually witness and document a hunt is rare.

According to Andrews, the gray whale was 10 to 15 feet longer than the killer whales, but that seemed to make little difference as the predators worked together to force the gray into deeper water.

"We think killer whales prefer the deep so they can get beneath their prey," Durban said.

But the gray whale was having none of it and, despite a prolonged struggle, finally managed to escape by swimming close to the beach.

The encounter left scientists shaking their heads.

"Mainly we see them take gray whale calves, which are smaller and not as strong," Durban said. "This was unusual to see them try to take an older yearling."

-- Kate Cheney Davidson

____________________________________

Sticker shock for scientists

For his Antarctica trip, biologist Russ Andrews tried five configurations of the tracking device.

"We try to be as minimally invasive as we can, so the barbs on the darts are pretty small," Andrews said.

Each tag is immersed in an epoxy that is waterproof and pressure-proof, and the barbs are made of medical-grade titanium. The price tag for each? $3,000.

Fortunately, Andrews says, he often recovers misses with an attached line.