As boats near, orcas have more to say

Like a chattering couple struggling to be understood over the ruckus of rush hour, killer whales increase their chitchat when powerboats are nearby, a new study shows.

In the April 29 issue of Nature, three researchers write that whales lengthen the duration of their calls when traffic approaches. The orcas -- black-and-white killer whales like Shamu -- started this behavior about a decade ago, when boat traffic increased off the coast of the Pacific Northwest, says co-author Richard W. Osborne of the Whale Museum in Friday Harbor, Wash.

The report mirrors other changes in killer whale behavior, says David Bain of the University of Washington, who was not part of the analysis of three decades of recordings.

A hungry and depleted species, orcas swim farther and stay under water longer than they once did, possibly because of boat congestion.

Their major food source, salmon, is dying out, and scientists consider the whales among the most polluted animals on earth.

“If you are sick and dying,” Osborne says, “you probably want to be in a quiet place and recover and not have a jackhammer going off right next to you.”

The researchers hope their findings will encourage private and commercial boaters to travel more slowly, reduce engine noise and stay farther from the orcas.

A group of commercial whale-watchers in the Pacific Northwest adopted similar guidelines about three years ago.

-- Ashley Powers