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Friday, October 1, 2010

On the brink: Penguins face an uncertain climate future

Early this year the African Penguin was redlisted by the International Union for the Conservation of Nature as in danger of extinction. In response to a 2006 petition by the Centre for Biological Diversity the US Interior Department has listed the African penguin, the only species of penguin breeding on the African continent, for protection under the US Endangered Species Act.

A pair of African penguins, Boulders Beach, South Africa

The International Union for Conservation of Nature (IUCN) upgraded the status of the Afican Penguin in 2010 to endangered citing "recent data has revealed that it is undergoing a very rapid population decline, probably as a result of commercial fisheries and shifts in prey populations. This trend currently shows no sign of reversing, and immediate conservation action is required to prevent further declines."

Related: Penguin numbers suffering with krill decline due to Global Warming (April 2011)

The African penguin has suffered a 60 per cent decline in population over the last 10 years and are estimated to now number about 25,000 breeding pairs. A species that numbered in the millions a century ago now faces a very real threat of extinction this century. Of the 18 penguin species, 10 are in serious population decline.

"African penguins are sliding toward extinction with no signs of stopping," said Catherine Kilduff, a Centre for Biological Diversity attorney in a media release. "Climate change, oil spills, overfishing and habitat destruction are among the many threats that the Endangered Species Act must begin to address."

"Industrial fisheries and ocean warming are starving the penguins. Longlines and other destructive fishing gear entangle and drown them," said Todd Steiner, biologist and executive director of Turtle Island Restoration Network (TIRN). "Finally the government is throwing penguins a lifeline to recovery by protecting them under the Endangered Species Act."

Industrial scale fishing has forced the African penguin to feed on less nutritious prey and to swim much farther in search of food. Climate change and ocean warming are also making the prey more scarce. Living around the coast of South Africa and Namibia they are prone to oil pollution from illegal operational discharges and shipping accidents along the coast, a major global oil transport route. Guano harvesting has eliminated much of their preferred nesting material, leaving them exposed to predators, heat stress, flooding and sea-level rise.

Most penguin species face the challenges of reduced prey from competing with commercial fish harvesting near penguin rookeries and feeding areas, particularly during breeding season, and the changes in climate and ocean chemistry.

Protected status under the US Endangered Species Act has now been bestowed on 6 penguin species, the Humboldt penguin of Chile and Peru , four New Zealand penguins (the yellow-eyed, white-flippered, Fiordland crested and erect-crested) and the African Penguin.

The Center for Biological Diversity and Turtle Island Restoration Network (TIRN) plan to file suit against the US Department of the Interior for denying listing to emperor (IUCN Status: Least Concern) and northern rockhopper (IUCN Status: Endangered) penguins despite scientific evidence that they are jeopardized by climate change and commercial fisheries.

Around Antarctica reduction in sea ice, ocean warming and ocean acidification is reducing one of the main penguin food sources - the small crustaceans known as krill. The Marine Stewardship Council earlier this year approved the continuation of krill harvesting as sustainable to manufacture feed for fish farming and nutritional supplements for humans and came under criticism by marine conservationists. (See also - Penguin numbers suffering with krill decline due to Global Warming - April 2011)

Krill are at the bottom of the food chain and are dependent on sea ice conditions for feeding on ice algae. Larger mammals such as whales, penguins and seals are dependant upon the large swarms of krill either directly or indirectly through the food chain. In winters with shorter and smaller sea-ice coverage, krill reproduction is markedly reduced. The Southern Ocean is also a major sink for atmospheric carbon dioxide which is progressively turning the water more acidic impacting on the ability of krill to form their shells. Krill feed on phytoplankton which absorbs carbon dioxide, thus sequestering some of this carbon to the deep sea floor.

According to the Antarctic Krill Conservation Project one study has estimated the amount of CO2 transferred to the ocean floor by millions of krill equals the annual emissions of 35 million automobiles.

We are living in one of the periods of mass species extinction. Already a major marine extinction is looming with ocean acidification. If greenhouse gas emissions remain on their current trajectory, climate change is projected to commit one-third of the entire world's species to extinction by mid-century.

The 18 species of penguins are our canaries in the coal mine of climate change.

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