Ocean Watch
By Susan Scott
Fin whales are becoming
ocean roadkillA couple of weeks ago, my brother-in-law, Burke, took his mother and sister on a motorboat ride off Orcas Island in Puget Sound. As they cruised, his mother asked about the small island just offshore.
"There's no island over there," Burke said, squinting at the mound. "It looks like the upturned hull of a ship."
Quickly he turned the boat to investigate. But as the boat drew near, they saw long, lengthwise stripes on the mound that looked like gill slits, only closed, and smelled a strong odor. This was no shipwreck. It was the upturned belly of an enormous whale.
The dead whale, it turned out, was one of four fin whales hit and killed by ships in the Pacific Northwest over a recent eight-week period.
Ships hitting whales is not a new phenomenon, but four in such a short time, in one area, is unusual. Officials think these huge whales had probably followed their prey of small invertebrates, schooling fish and squid into shipping lanes.
You might think that running into a 75-ton whale would attract a captain's attention. It doesn't. Bulbous-bowed container ships weigh tens of thousands of tons and cruise at more than 20 miles an hour. A whale in such a vessel's path makes no more of an impact than a bug on windshield.
Fin whales are second in size only to blue whales, growing to about 79 feet long in our hemisphere and about 89 feet long in the Southern Hemisphere. Blues grow to 98 and 110 feet, respectively.
It's ironic that fin whales are becoming roadkill in the Pacific Northwest because these animals are fast. Known as greyhounds of the sea, these sleek whales can swim in bursts of up to 25 miles an hour. Unfortunately, even though they are capable of dodging container ships, they don't know they should.
Fin whales are close relatives of our more familiar humpback whales and have similar lifestyles. Both eat plankton by sifting water through comblike plates, called baleen, hanging from the whales' upper jaws. The two species also migrate from cold water, where the food is plentiful, to warm water to bear their young.
Also like humpbacks, fin whales sing courtship songs, making them detectable.
Even though researchers have not identified any distinct breeding and mating grounds for fin whales, they do visit Hawaiian waters. Using hydrophones, biologists discovered regular winter occurrences of fin whales off Kaena Point.
Fin whales aren't seen here often, but there's always the chance of spotting one. You'll know if you do. Besides being much longer than our humpbacks, which grow to about 45 feet, fin whales have a chevron-like V-shape behind the head and a lower jaw with unusual colors: The right side is always white, the left always black. No one knows the meaning of this odd coloration.
Those belly stripes that my mother-in-law mentioned in her e-mail to me are called ventral pleats. These extend from the lower jaw to the animal's midsection and expand when the whale scoops up a mouthful of water. When the whale expels the water, the pleats contract.
Fin whales roam tropical, temperate and polar regions of all oceans and often swim near shore. I would love to see a fin whale but not belly up. Hopefully Puget Sound's fin whales have moved from the fast lane to the exit ramp, and will visit Hawaii for the holidays.
Marine science writer Susan Scott can be reached at http://www.susanscott.net.
