Tara Stevens, who is finishing her doctorate at the University of Rode Island, has been studying the estimated 200 killer whales believed to live around the area of Newfoundland.
During her study she found that Minke whales seem to be the predominant prey of this population. Killer whales subdue the larger animal by attempting to drown it. 10 – 20 killer whales will be jumping on a minke whale’s back in an attempt to force it underwater.
Her study indicates that they don’t hunt exclusively on Mine whale though as they have been seen taking dolphins, porpoises and seals. Though it is possible they also take fish, some whales have been seen to take halibut and tuna off of longlines. When the tuna fishery was going strong in the Gulf of Maine killer whales regularly took tuna off longlines, but after the fishery crashed the fishermen didn’t see killer whales any more. The killer whales might have left or switched food sources.
It is too early to determine if there are multiple ecotypes in area (prey specialists) but Stevens believes that the killer whale’s movements are based on following prey. Some killer whales that stay in Newfoundland and Labrador year round have been seen in pack ice feeding on breeding seals.