Penguin plunge sends ocean warning signal

Posted: 17 November 2008

Plunging penguin populations are a signal that the world's oceans are suffering the effects of climate change, fishing and oil and gas development, according to an analysis that could provide new ammunition for groups seeking global protection for the birds.

The paper's author, University of Washington conservation biologist P. Dee Boersma, who has studied the birds for more than 30 years, says that in recent decades, populations of the world's 16 to 19 penguin species have begun to dwindle, with about two-thirds now under threat. "Life is not likely to get easier for penguins," Boersma reports. "They have to withstand both climate variation and human development."

Oiled Jackass penguins, South Africa.
Oiled Jackass penguins, South Africa.
Oiled Jackass penguins, South Africa. © International Fund for Animal Welfare (IFAW).
Boersma, who has tracked penguins at Punta Tombo, Argentina (the largest breeding colony in Patagonia) for 25 years, says that the number of breeding pairs there fell from about 400,000 in the late 1960s to about 200,000 in 2006.

On the Antipodes Islands - about 500 miles from the New Zealand coast - the number of erect-crested penguin breeding pairs dropped by half between 1978 and 1995, to about 50,000. And on the northern tip of the Antarctic Peninsula, the numbers of Adélie and chinstrap penguins have shown a similar decline, having fallen by about 50 per cent since the mid-1970s.

In the United States, the Fish and Wildlife Service is considering extending Endangered Species Act protections to 10 penguin species in South America, southern Africa and Antarctica. The agency said last summer that listing the birds "may be warranted" but failed to meet a November deadline for deciding whether the species qualify and proposing a listing. The Center for Biological Diversity has filed suit against the agency in an effort to speed up its decision-making process.

'Marine sentinels'

One looming threat for many penguin species is climate change. Rising temperatures and declining sea ice cover are shifting breeding grounds and reducing the amount of food available for some birds.

One study, published in February in Proceedings of the National Academy of Sciences, predicts that if the Southern Ocean warms by 0.47 degrees Fahrenheit, changes in the migratory patterns of fish and declines in the krill population could cause a sharp drop in the number of king penguins - a species that rebounded from near-extinction over the past century.

In the new paper, Boersma recounts her first-hand experience in late 2005 at the French base at Dumont d'Urville, Antarctica. Emperor penguins wintering in the area - featured in the film March of the Penguins - were forced to move their breeding site by 3 miles to find sturdy sea ice and strong enough winds to keep the area snow-free, since their chicks take months to develop enough feathers and fat to survive on their own.

But by September 2006, a storm broke up that ice, putting the colony's half-grown chicks in the water, with the likely result of a "total colony-wide breeding failure," Boersma said.

Other threats the birds face include the rise of tourist traffic to breeding colonies, commercial fishing, energy exploration and marine pollution.

In the end, Boersma said, penguins have become "marine sentinels" that point to a need for better stewardship of the oceans. "Penguins face a gauntlet of environmental challenges, from climate change to human take," she said.

Click here to read Boersma's article in the July/August editing of Bioscience.