[CINC] SFGate: Gray whales - a study in climate change survival

[JohnKuizenga]

 Interesting article on Gray Whales adaptation to utilizing different food
sources over the past one hundred thousand years or so. JK
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This article was sent to you by someone who found it on SFGate.
The original article can be found on SFGate.com here:
http://www.sfgate.com/cgi-bin/article.cgi?file=/c/a/2011/07/11/MN0J1K7LKM.DTL
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Monday, July 11, 2011 (SF Chronicle)
Gray whales - a study in climate change survival
<a class="email fn" href="mailto:dperlman at sfchronicle.com">David Perlman, Chronicle Science Editor</a>


   The massive gray whales that migrate each year between Alaska's Bering Sea
and Baja California have survived thousands of years of sea level and
climate change by altering the way they live and feed, UC Berkeley
scientists have found.
   And those major adaptations, they say, could put them in good position to
withstand climate change taking place today.
   Long before now, the scientists said - perhaps 2 million years ago or more
- evolution shaped gray whales' skulls, allowing them to find food in two
very different ways.
   Today, they can dive to the ocean bottom and suck up the muddy sediments
that their whisker-like baleen will filter out to get tons of nutritious
worms and tiny crustaceans - as much as 900 pounds a day. Or they can swim
through the open water with mouths agape to filter out masses of krill,
herring and other small fish. Year-round stay
   One small group of gray whales along the North Pacific coast no longer
migrates to the Bering Sea from Baja each year nor forages for food in the
ocean sediments off Alaska.
   Instead, those whales remain year round near Vancouver Island in Canada
and off the tiny Humboldt County town of Trinidad, a onetime whaling
center. They use what the scientists call a "diverse set of feeding modes"
that has turned them into hunters of the open ocean - like their
relatives, the blue whales and the humpbacks.
   It's a behavioral change that has occurred since the last ice age ended
some 10,000 years ago and sea levels rose, and that the evolution of their
skulls made possible so long ago.
   David Lindberg, an evolutionary biologist at Berkeley, and Nicholas
Pyenson, a former Berkeley graduate student and now curator of fossil
marine mammals at the Smithsonian Institution in Washington, used the many
cycles of past climate and sea level changes to study the whales' survival
patterns.
   Their study is published in the current issue of the online journal PLoS
One.
   The scientists focused on the changes in sea levels that occurred between
120,000 years and 10,000 years ago. In that period, glaciers and ice
sheets alternately advanced far south from the Arctic, and retreated again
and again as the climate changed. Diversifying
   The oceans also froze and sea levels shrank, then warmed again, and sea
levels rose. With those changes came changes in the availability of food.
Some whales, including the grays, met those challenges by diversifying
their way of life, the scientists have found.
   Lindberg and Pyenson estimate that long before the arrival of humans on
the West Coast, gray whales throughout the North Pacific could have
numbered as high as 120,000. But commercial whaling began about 1845,
continued into the early 20th century and killed off thousands of whales
of virtually every species.
   Rigorous protection since then has restored gray whale numbers to about
22,000, Lindberg and Pyenson estimate, and as climate change continues and
the water of the North Pacific Ocean warms, the "plasticity" of the gray
whales - their ability to find food in diverse ways - should give them a
distinct advantage, they say.
   "I suspect the gray whales will be among the winners in the great climate
change experiment," Pyenson said.

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