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April 29, 2009

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Penguin populations falling steeply: biologist

July 1, 2008
Courtesy University of Washington
and World Science staff

Like the pro­ver­bi­al ca­nary in the coal mine, pen­guins are sound­ing the alarm for po­ten­tially cat­a­stroph­ic changes in the world’s oceans, a Uni­ver­s­ity of Wash­ing­ton bi­olo­g­ist says.

The cul­prits are glob­al warm­ing, oil pol­lu­tion, de­ple­tion of fish­er­ies and ram­pant coast­line de­vel­op­ment, which threat­en breed­ing hab­i­tats for many pen­guin spe­cies, she ar­gues.

Rain has soaked this Adé­lie pen­guin chick in Ant­arc­ti­ca be­fore its feath­ers are ca­pa­ble of re­pel­ling wa­ter. Though the icy con­ti­nent is in es­sence a des­sert, coast­al rain­fall is be­com­ing more com­mon with chang­ing cli­mate. (Cour­te­sy Dee Boersma)

Like the proverbial canary in the coal mine, penguins are sounding the alarm for potentially catastrophic changes in the world’s oceans, a University of Washington biologist said. The culprits are global warming, oil pollution, depletion of fisheries and rampant coastline development, which threaten breeding habitat for many penguin species, she argues. These factors are behind rapid population declines among the birds, said the university’s Dee Boersma, an authority on the flightless birds. “Penguins are among those species that show us that we are making fundamental changes to our world,” she said. “The fate of all species is to go extinct, but there are some species that go extinct before their time and we are facing that possibility with some penguins.” In a paper published in the July-August edition of the research journal BioScience, Boersma notes there are 16 to 19 penguin species, and most penguins are at 43 sites, virtually all in the Southern Hemisphere. For most of these colonies, population trends have been unclear, so few people realized that many penguins were experiencing sharp population declines, Boersma said. She advocates an international effort to check on the largest colonies of each penguin species at least every five years. Working with the Wildlife Conservation Society and colleagues, Boersma has studied the world’s largest breeding colony of Magellanic penguins at Punta Tombo on Argentina’s Atlantic coast of Argentina. That population probably peaked at about 400,000 pairs between the late 1960s and early 1980s, and today is half that, she said. There are similar stories from other regions. African penguins decreased from 1.5 million pairs a century ago to just 63,000 pairs by 2005, Boersma claimed. Galapagos Islands penguins, the only species whose range extends into the Northern Hemisphere, now number around 2,500, about a quarter of what their population was when Boersma first studied them in the 1970s. Boersma recounts watching in 2006 as climate anomalies wreaked havoc on the same population of Emperor penguins featured in the popular 2005 film “March of the Penguins.” The colony bred in the same place as in other years, where the ice is protected from the open sea and wind keeps snow from piling up and freezing the eggs. But in September, with the chicks just more than half-grown, the adults apparently sensed danger and uncharacteristically marched the colony more than 3 miles to different ice. The ice they chose remained intact the longest, but in late September a strong storm broke it up and the chicks were forced into the water, Boersma said. While the adults could survive, the chicks needed two more months of feather growth and buildup of insulating fat to be independent. The likely result, Boersma said, was a total colonywide breeding failure that year. Global warming also appears to be key in the decline of Galapagos penguins, she said: as the atmosphere and ocean get warmer, El Niño Southern Oscillation events, which affect weather worldwide, seem to occur more often. During those times, ocean currents that carry the small fish that penguins eat are pushed farther away from the islands and the birds often starve or are left too weak to breed. These problems raise the question of whether humans are making it too hard for other species to coexist, Boersma said. Penguins in places like Argentina, the Falklands and Africa run rising risks of being fouled by oil, either from ocean drilling or because of petroleum discharge from passing ships. The birds’ chances of getting rising are also increasing because in many cases they have to forage much farther than before to find the prey on which they feed. “As the fish humans have traditionally eaten get more and more scarce, we are fishing down the food chain and now we are beginning to compete more directly with smaller organisms for the food they depend on,” she said. As the world’s population continues to explode and more and more people live in coastal areas, the negative effects are growing for both marine and shore-based habitats used by a variety of species, Boersma added. “I don’t think we can wait. In 1960 we had 3 billion people in the world. Now it’s 6.7 billion and it’s expected to be 8 billion by 2025,” she said. “We’ve waited a very long time. It’s clear that humans have changed the face of the Earth and we have changed the face of the oceans, but we just can’t see it. We’ve already waited too long.”