Warming effect on main food hits penquins

A climate change related-decline in Antarctic penguin numbers is due more to loss of their primary food source than to habitat change, researchers say. Two penguin species in the study, published in the Proceedings of the National Academy of Sciences, rely on small shrimp-like creatures known as krill for their survival. Previous assessments suggest the abundance of krill has declined as much as 80 percent since the 1970s. The decline in numbers has hit both species of penguins despite their preference for different habitats, researchers said. A 30-year field study of Adelie penguins, which live on sea ice, and chinstrap penguins, which avoid ice, shows populations of both species in the West Antarctic Peninsula and Scotia Sea have declined for at least the last 10 years, with some colonies decreasing by more than 50 percent. "For penguins and other species, krill is the linchpin in the food web. Regardless of their environmental preferences, we see a connection between climate change and penguin populations through the loss of habitat for their main food source," said Dr. Wayne Trivelpiece of the National Oceanic and Atmospheric Administration's Antarctic Ecosystem Research Division. "As warming continues, the loss of krill will have a profound effect throughout the Antarctic ecosystem. "Penguins are excellent indicators of changes to the biological and environmental health of the broader ecosystem because they are easily accessible while breeding on land, yet they depend entirely on food resources from the sea," Trivelpiece said.