Puzzling
Deaths of Gray Whales Off California Coast Probed
From a news story by
CNN San Francisco Reporter Rusty Dornin
May 1, 2000
By the time this gray
whale washed up dead at the foot of the Golden Gate Bridge last week,
researchers were scratching their heads. Over the last three weeks,
eleven gray whales have mysteriously died and floated ashore in San
Francisco Bay.
Starvation was blamed for most of the 270 deaths of gray whales last
year along their migration route but this year the dead whales seem
to have a bit more blubber.
"Although we've had a few animals that were very, very thin, we've
had even more animals that were in very good body shape, which probably
indicates there is more to it than just a nutritional problem,"
said Martin Haulena of the Marine Mammal Center.
The gray whale population, once endangered, rebounded from 15,000 to
26,000 over the last 20 years.
More whales create more pressure on the food supply, a supply that some
scientists say may have dwindled as a result of the warm waters of El
Nino.
At a 7,000 mile round trip migration from Alaska to Mexico, they (researchers)
still believe starvation is still the strongest theory.
"They're traveling this long distance; they don't have enough to
eat -- now they've got to migrate south to breed with low body reserves,"
said University of California-Santa Cruz emeritus professor of biology
Burney J. Le Boeuf.
Finding answers becomes a
problem when most of the whales wash ashore badly decomposed and difficult
to autopsy.
"There might be a whole bunch of different things going on,"
Haulena said. "The animals we have been able to examine in past
years, we've seen a pneumonia, we've seen probably a brain infection
and encephalitis."
Oceanic Society researcher Caitlyn Toropova is looking for live grays
(whales). This year there have been 65 sightings of the behemoths, more
than three times the number seen last year.
Toropova said: "We done a study to figure out what's going on with
the live whales in the bay to maybe give some insight into what's happening
with the ones that are washing up dead."
A once endangered species that some scientists
believe may be suffering the effects of overpopulation.
Additional Notes:
Every year gray whales
migrate from the Bering Sea in Alaska to the Baja Peninsula in Mexico.
This is a journey of 7,000 miles (some researchers think it is closer
to 10,000 miles) the longest migration of any marine mammal. The whales
feed in the Bering Sea in summer and then migrate to Mexico to have
their babies. They do not eat anything on their long migration until
they return to Alaska - 3 to 5 months later. More of the whales are
dying during the migration and many of them are adults.
Here is a wonderful tutorial that shows the migration, feeding and
calving of gray whales:
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