Environment

Seven orca whales missing off the coast of British Columbia deemed “disaster” by marine researchers

by yuls.source | October 25, 2008 at 11:03 am

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Seven whales are missing and presumed dead at Puget Sound near Seattle, USA. This has marine scientists ringing alarm bells. The loss of seven animals is the biggest orca species decline in the last 10 years. Meanwhile, researchers are trying to investigate what could have caused this population decline. The most obvious reason seems to be the lack of sufficient food supply. Orcas are having a hard time finding enough salmon to consume this year. Other possible reasons for the unusually high number of orca deaths are pollution and sonar frequencies used by naval ships. Among missing animals are the 98-year-old male and the mother of Luna, a baby killer whale that liked to follow tugboats near Vancouver Island until it was killed by a boat propeller in 2006. Orcas are considered an endangered species since 2005.

Seven Puget Sound killer whales are missing and presumed dead in what could be the biggest decline among the sound's orcas in nearly a decade, say scientists who carefully track the endangered animals.

"This is a disaster," Ken Balcomb, a senior scientist at the Center for Whale Research on San Juan Island, said Friday. "The population drop is worse than the stock market."

Low numbers of chinook salmon, a prime food for these whales, may be a factor in the unusual number of deaths this year, Balcomb said.

"It was a bad salmon year and that's not good for the whales," he said. "Everybody considers these wonderful creatures, but we really have to pay attention to the food supply."

Lack of food may be a concern, but it's too early to know the reason for the unusual number of presumed deaths, he said.

Pollution and a decline in prey are believed to be the whales' biggest threats, although stress from whale-watching tour boats and underwater sonar tests by the Navy also have been concerns. In the late 1960s and early '70s, the population fell as dozens were captured for marine parks.

The whales were making an apparentg comeback in recent years, reaching 90 in number in 2005, "but it's been a downhill trend now for three years," Balcomb said.

Among those missing are two female whales of reproductive age, both of which recently produced calves. One of those calves, L-111, is missing, while the other, J-39, is not.

It's not unusual to lose older or younger whales, but losing two females in reproductive prime is "a bit of a concern" since they typically have a high survival rate, Hanson said.