Washington Orca Population Heads South to Feast on Chum Salmon
SEATTLE, Washington Washington state's resident killer whales, with two newborns in tow, dodged a potentially lethal roadblock in their voyage south to feast on a healthy run of chum salmon, experts say.
If the orcas had departed a week earlier, they could have run into pollution from the 1,000-gallon oil spill near Tacoma, Washington, said Ken Balcomb at the Center for Whale Research in the San Juan Islands.
"Hopefully they'll skirt the spill," Balcomb said, referring to thin deposits that cleanup technology cannot recover. "As long as the whales don't swim through it and inhale it," they should be OK, he said.
Researchers had attributed the deaths of several Alaska killer whales to the 1989 oil spill from the tanker Exxon Valdez in Prince William Sound.
Orcas are at risk from such disasters because they have no sense of smell, Balcomb said. Newborns are especially vulnerable.
"It could have been plus two and minus two in one day," he said. "It isn't good for adults either, but little babies you can imagine putting your baby in a fume-filled room. It wouldn't be good for them."
The calves were born over the past 10 days. The births bring the state orca population to 85, well below the 99 counted in 1995.
The orcas are designated a depleted population under the federal Marine Mammal Protection Act and endangered under state law. The births are good news for the population but not a sure bet.
"The calves don't really count till they become sexually mature," Balcomb said. Killer whale development roughly parallels that of humans, with sexual maturity coming in the teens.
The fall run of chum, or dog salmon, is just starting, as the 10- to 30-pound fish leave the ocean to head for their nascent streams, where they spawn and die. The run lasts into January.
How do the whales know the chum are running?
"Oh, they're just wise," Balcomb said. "They've been doing this for thousands of years. They know they're there. They echo-locate and find them."
Echolocation allows the animals to bounce sounds off objects to monitor their surroundings and find prey.
Source: Associated Press