Scientists Want New Name For Mammal-Eating Orcas
ANCHORAGE, Alaska (AP) — If whale expert John K.B. Ford has his way, school children one day will study a kind of North Pacific killer whale that preys on warm-blooded creatures — mostly harbor seals and sea lions, but also gray whales and seabirds.
They roam as far north as the Arctic Ocean and are now known as “transients” to distinguish them from fish-eating “resident” killer whales.
Ford and colleagues from Alaska to California want transient killer whales to be declared their own species, and they want them to have a new name: Bigg’s killer whales, in honor of Michael Bigg, the researcher whose observations off British Columbia and Washington state led to the identification of transients and whose mentoring inspired a generation of researchers still uncovering the mysteries of the animal at the top of the marine food chain.
“He was really very much the founding father of modern scientific studies regarding killer whales,” Ford said from his office at the Pacific Biological Station in Nanaimo, B.C., where he heads West Coast cetacean research for Canada’s Department of Fisheries and Oceans.
Paul Wade, a U.S. killer whale expert at the National Marine Mammal Laboratory in Seattle, said colleagues have begun using Bigg’s killer whales as the common name for transients in research papers.
“It seems to be catching on,” Wade said.
Work demonstrating that Bigg’s killer whales are a separate species also is progressing, he said, and that could lead to honoring Bigg with a formal scientific name for transients.
Michael Andrew Bigg was born in London in 1939. He moved to British Columbia with his family nine years later. He had a lifelong fascination with predators, Ford said, and for a time was a falconer.
“He was kind of a rare generalist as a biologist,” Ford said. “He was broadly interested in natural history.”
Just out of graduate school in 1970, Bigg was hired as a marine mammal biologist at the Pacific Biological Station. One assignment was an investigation of the status of killer whales, considered dangerous to humans and pests by salmon fishermen. By 1973, aquariums were paying $70,000 for a live killer whale and 48 had been captured for display.
Bigg and colleagues distributed sighting forms to fishermen and other coast residents. His report in 1976 concluded that just 200 to 350 orcas remained along the B.C. and Washington coasts, far fewer than thought, and too few to sustain additional live captures.
He also made a breakthrough that would create the framework for decades of additional research: He determined that individual whales could be identified by pigmentation patterns on the saddle patch at the base of their dorsal fins. That meant researchers could track whales to figure out their diets, family dynamics and communications with other whales.
“It was Mike’s realization that with a good-enough photograph, you could identify even the plainest looking fin without any obvious markings,” Ford said.
Bigg’s formal association with killer whales ended by early 1977. He was reassigned to other marine mammals, including northern fur seals, Ford said, but kept at killer whale research on the side. He had started to distinguish families of resident orcas that he suspected were targeting salmon. More rarely seen were killer whales that Bigg at first suspected were pod outcasts.
They turned out instead to be mammal-eaters. Genetic work on transients followed. Wade collaborated with National Marine Fisheries Service geneticist Phillip Morin and 14 other researchers on a 2011 paper that indicated resident and transient killer whales don’t eat or behave the same ways. They also don’t interbreed.
“The evidence suggests that the transients in particular are quite different than everybody else and probably shared an ancestor about 700,000 years ago,” Morin said from the Southwest Fisheries Science Center in La Jolla, Calif.
The scientists say at least three killer whale species likely roam the North Pacific, including offshore orcas that may feed on sleeper sharks, and three in the Antarctic. Killer whales are found in every ocean and DNA samples have been studied from the extreme north and south parts of the globe. Researchers are preparing to analyze samples from tropical and temperate waters, Morin said, to piece together the pattern of evolutionary divergence between types.
“The goal is to then try to compile the genetic data with all of other data — the behavioral, the acoustic, other molecular data, distribution — and come up with a description of killer whales globally, along with our recommendations for which should be species and which should be subspecies, if the data hold up those categories,” Morin said.
Bigg’s influence on other scientists may have been as meaningful as his research. He shared his work and often his home with newly graduated marine biologists from the United States, France, Sweden, Norway, Mexico and Argentina, inviting them to unlock additional secrets about killer whales in their parts of the world, Ford said.
Ford was one of them. Bigg helped him find a boat for his first field work. Ford went on to study underwater acoustic signals in social communication of killer whales for identification and description of dialects from whale groups.
Bigg was diagnosed with leukemia in 1984 and died in 1990 at the age of 51.
The idea for naming transients, Ford said, came from the Vancouver Aquarium researcher Lance Barrett-Lennard and John Durban of the Southwest Fisheries Science Center as they studied killer whale predation on gray whales at False Pass in Alaska’s Aleutian Islands.
“Mike would be incredibly fascinated with the information that’s still coming to light,” Ford said.
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