Where Have The Orcas Gone?

Sunday, October 26, 2008
VANCOUVER, BRITISH COLUMBIA - The disappearance of seven orcas from B.C. coastal waters is being blamed on a "double whammy" of low chinook salmon numbers and toxins being dumped in the ocean.

"We lost seven over the last year but we had one birth, so the total population change was six," said Susan Berta, of the Washington state-based Orca Network. "Several of the whales we lost were females of reproductive age, which is very troubling to lose."

Berta said the 83 remaining orcas from three groups -- J, L and K pods -- have had to change their foraging behavior due to scarce chinook salmon, their preferred food.

"They aren't finding enough salmon where they have historically fed," Berta said. "The Columbia River used to be their favorite grocery store but the chinook runs there have declined.

"When there aren't enough chinook, we see stuff like this happening with whales looking thin. They'll eat chum salmon in the fall, but they prefer chinook."

The oldest of the missing orcas is K-7, a 98-year-old female.

More troubling, said Berta, was the death of L-67, a 23-year-old female. Orcas begin reproducing at age 14 or 15 and continue until their mid-40s.

"She was Luna's mother," Berta said. "Her six-year-old calf, L-101, is missing and he was Luna's brother."

Luna made headlines while living alone in Nootka Sound from 2001 to 2006 as he interacted with people. He was killed when he was hit by a tugboat propeller.

Berta said a similar pattern was witnessed in 1999 when 20 per cent of the orca population was lost during a six-year span, which correlated with a decline in chinook.

It puts the orcas up against what Berta called a "double whammy."

"The other thing they are faced with are toxins and PBDE, a fire retardant showing up in high levels in marine mammals," Berta said. "When they can't eat salmon, they feed off their own blubber -- and that is where the contaminants are stored. It unleashes toxins into their system and that can cause problems with their immune system and reproductive systems.

"It's a double whammy."

Source: The Vancouver Province