Marine Scientists Warn of Broad Threats to World Whale Populations
Humpback whale (Megaptera novaeangliae). Image courtesy OAR/National Undersea Research Program (NURP); University of North Carolina at Wilmington
Top marine scientists warned Saturday that whales globally are being threatened by pollution, hunting and "acoustic smog" caused by shipping and other human activities, and that the degradation of the oceans also poses risks for billions of people.
In a grim assessment of conditions, scientists at a AAAS news briefing pointed to the struggles of the Right whale in the Northern Hemisphere as a possible harbinger. With noise permeating the seas and toxic chemicals pervasive, its population in the North Atlantic is "collapsing," said Roger S. Payne, founder and president of Ocean Alliance.
Payne has studied the behavior of whales for nearly 40 years; he is a biologist, author, and MacArthur Fellow. He is best known for his discovery that humpback whales sing songs and for his theory that the songs of fin and blue whales can carry across oceans.
During the briefing at the AAAS Annual Meeting, he stressed the potential harm that could be caused by toxic chemicals. In a recent study of sperm whales, researchers were able to assess the presence of the chemical in polar seas, where male sperm whales spend part of each year, and in temperate seas, where female sperm whales live permanently and mate with migrating males.
The result, Payne said: Chemicals in the class of "persistent organic pollutants"highly toxic compounds such as DDT, PCBs and dioxinwere found in every sample.
"Whales are not the only long-lived mammals that eat a lot of seafood," he said. "So do we." And because 70 percent of the Earth's human population depends on seafood as the main source of protein, he added, the long-term consumption of contaminated fish could affect more than 4 billion people. The health crisis could be unprecedented, Payne said.
Christopher Clark, director of Cornell University's Bioacoustics Research Program, has spent nearly nine years using the U.S. Navy's Cold War era Sound Surveillance System, an extensive network of highly sensitive undersea monitors. Everywhere, Clark said, "the oceans are singing" with the calls of whales.
But because of shipping, oil exploration and underwater military activity, the amount of noise is doubling every decade, he says. Where a blue whale song might travel 1,600 miles underwater, now the call might be lost in the acoustic fog, discernable only at much closer range.
That could have an impact on whale mating activity or on food-hunting, Clark said.
Steven R. Palumbi, who heads a marine lab at Stanford University, described finding whale blubber in Japanese markets. And Payne blamed Japanese officials for using laws that allow whale hunting for research as a loophole to continue traditional whaling that would otherwise be limited or banned.
Craig Smith of the University of Hawaii has done path-breaking work on the life communities that develop on the carcasses of dead whales that fall to the ocean floor, and this work is shedding new light on bizarre species of bone-eating worms and other exotic creatures that appear to play a crucial role in the ocean ecosystem.
But fewer whales means fewer whale falls, he told reporters. If whale falls are reduced by 50 percent, he said, as many as 15 percent of whale-fall species may go extinct.
The news isn't all bad, the scientists said. Some species of whales have stabilized after prolonged declines. Globally, illegal whaling appears to be on the decline. And the Right whale, while suffering in the north, is proliferating in the Southern Hemisphere, perhaps because the waters are cleaner and quieter.
Edward W. Lempinen
19 February 2005