Scientists Fear Gray Whales Are Adversly Affected By Global Warming
Scientists on the US Pacific coast are increasingly observing emaciated gray whales in what they fear is a sign that global warming is wreaking havoc in the whales’ Bering Sea summer feeding grounds.
The scientists fear that the same phenomenon is cutting back reproduction in the Pacific whale population to the point it could be facing a new crisis, after recovering in the mid-1990s and graduating from the endangered species list.
“The gray whales are migrating later, not going as far north, and are producing fewer calves,” Steven Swartz, head researcher with the National Marine Fisheries Service told AFP.
Swartz, who with his team meticulously photograph and identify the migrating whales, estimates that at least ten percent of the population is seriously skinny.
“Instead of looking plump coming off the summer months, they have noticeable depressions behind the head, with scapulas visible through the skin, and concave sections above the tail,” he added. “This is enough to cause alarm.”
Swartz has studied the pacific whale population since 1977 and last saw a major whale die-off in 1999 when an El Nino warming cycle left traditional northern feeding grounds barren and claimed one third of the population.
He has partnered with scientists at the Autonomous University of Baja Sur, Mexico since 1996, keeping tabs on the whales’ calving and migration, the longest of any mammal.
The most recent gray whale survey in 2001 showed a decrease of thirty percent in five years. Researchers are now holding their breaths while final tabulations are completed on a current survey, and are bracing for another drop, said Swartz.
“We have yet to find any indications of disease in the population,” said Swartz. “When times are tough and there is less food out there, the whales do not reproduce. It’s possible that they are birthing somewhere else, but we have a lot of people looking, and we have not found them.”
The San Ignacio lagoon, one of four gray whale breeding grounds off the Pacific coast of Mexico, can be used as a litmus test for the reproductive rate of the species, said Swartz.
In the early 1980s, 350 calves were born in these waters every February. This past winter the number was closer to 100.