Undiagnosed Whale Deaths

Reuters, 21 Apr 2000

Gray whales are again washing up dead on North America's Pacific Coast, but
experts said they do not know if it is evidence of a problem or if the
whale population has returned to a healthy balance.

Nearly 30 gray whales have been found dead from California to British
Columbia in recent weeks as the mammals make their annual migration from
their breeding grounds off Mexico to summer feeding grounds in the Bering
Sea off Alaska.

At one time, gray whales had been hunted nearly to extinction, but
researchers estimate there are now about 26,000, close to the same number
believed to have existed before large-scale commercial whaling began in the

Trade in the gray whale has been outlawed since 1949, allowing the
population to recover.

The 273 gray whales found dead last year along their migration route was 5
times the number normally found, so researchers are not surprised to hear
of deaths again this year, said Peter Ross of the Institute of Ocean
Sciences in Victoria, British Columbia.

Researchers are also concerned the deaths could be the result of
environmental changes in the Bering Sea having caused a drop in the whale's
primary food supply - tiny amphipod crustaceans.

The whales, which can weigh up to 36 tons and live as long 60 years, spend
the summer in the Bering's cold waters eating and building up a reserve of
fat they live on for the rest of the year.

"The Bering food supply, used by whales and other animals such as sea
lions, has been dropping for 2 decades but researchers do not know why,"
said Donald Schell of the University of Alaska in Fairbanks.

"It may be because the whales are beating it down. It may be because of
environmental reasons," Schell said. Many of the adult whales found dead
last year were emaciated, indicating they had not been able to eat enough
to make the journey. Tissue samples have been taken from the animals
discovered this year.

Scientists are sampling dead whales' fat for toxins. But Ross, a
toxicologist, said he does not believe pollution is the direct cause of
death of the animals discovered so far.

Researchers acknowledge since the deaths occur at sea, the carcasses
discovered washed ashore represent only a small portion of the actual death
toll. "I would be concerned if these sentinels are telling us about the
state of the  oceans," Ross said.