New report shows variety in killer whale eating habits

Study marks 1st time sea otters have been found inside an orca

Posted: Tuesday, November 23, 2004

ANCHORAGE - A new report documents the varied diet of a Prince William Sound killer whale that washed up dead on Latouche Island in 2003.

The orca had last eaten at least five sea otters, seabird feathers, seaweed and about nine pounds of rocks, according to the analysis, which marks the first time sea otter remains have been documented inside a killer whale's stomach, according to biologists.

The belly of the big male also contained parts of nine harbor seals, some river otter teeth, a sliver of a clam's siphon and an octopus's beak, according to biologist Lori Quakenbush with the state's Arctic Marine Mammal Program in Fairbanks.

The analysis is summarized in a report submitted this fall to an academic journal.

Snatching otters or birds would be highly unusual behavior for the Sound's marine mammal-eating killer whales, said biologists Craig Matkin and Lance Barrett-Lennard with the North Gulf Oceanic Society in Homer.

Through 20 years of study, the whales have been seen pursuing much larger harbor seals and Dall's porpoises. They were not thought to be consumers of smaller prey, partly because that would offer so little nutritional payoff for 10-ton predators.

"This would be the kind of thing I would expect out of a lone animal," Matkin said. "This was an alternative to starvation."

The 23-foot carcass with a 4-foot-tall dorsal fin grounded in Latouche Passage in April 2003, too decomposed to be identified from its markings. Federal biologists and a veterinary pathologist took skin samples for genetic examination, several teeth, hunks of blubber for contaminant tests - and the whale's 3-foot-long, multichambered stomach.

The organ, which weighed 70 pounds, was frozen and sent north to Quakenbush's lab for an examination, said Barbara Mahoney with the National Marine Fisheries Service in Anchorage.

The genetic test identified the carcass as an AT-1 whale, from an isolated group that lost 14 of 22 members over the past 15 years. The population has since been listed as depleted under the Marine Mammal Protection Act. Biologists are working on a conservation plan.

The whale could be one of three males missing from the group but was probably an animal designated as AT14, with the nickname of Eccles, according to Matkin.

That whale, born about 1962, always hunted seals and porpoises with another male nicknamed Eyak. After Eyak stranded and died outside Cordova in 2000, Eccles was seen wandering alone for several years.

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