Discovery reports that Chinstrap and Adélie penguins have declined by more than 50 percent since 1980.This is because their main food source — krill — have declined by up to 80 percent.Krill rely on sea ice to reproduce, and sea ice levels have declined dramatically.
The Chinstrap Penguin (Pygoscelis antarcticus) is a species of penguin which is found in the South Sandwich Islands, Antarctica, the South Orkneys, South Shetland, South Georgia, Bouvet Island and Balleny. Their name derives from the narrow black band under their heads which makes it appear as if they are wearing black helmets, making them one of the most easily identified types of penguin. Other names for them are “Ringed Penguins”, “Bearded Penguins”, and “Stonecracker Penguins” due to their harsh call.
The Adélie Penguin, Pygoscelis adeliae, is a species of penguin common along the entire Antarctic coast. They are among the most southerly distributed of all seabirds, along with the Emperor Penguin, South Polar Skua, Wilson’s Storm Petrel, Snow Petrel, and Antarctic Petrel. In 1840, French explorer Jules Dumont d’Urville named them for his wife, Adélie.
Antarctic krill, Euphausia superba, is a species of krill found in the Antarctic waters of the Southern Ocean. Antarctic krill are shrimp-like invertebratesor crustaceans that live in large schools, called swarms, sometimes reaching densities of 10,000–30,000 individual animals per cubic meter. They feed directly on minute phytoplankton, thereby using the primary production energy that the phytoplankton originally derived from the sun in order to sustain their pelagic (open ocean) life cycle. They grow to a length of 6 centimetres (2.4 in), weigh up to 2 grams (0.071 oz), and can live for up to six years. They are a key species in the Antarctic ecosystem and are, in terms of biomass, probably the most abundant animal species on the planet (approximately 500 million tonnes)
In a paper published in Proceedings of the National Academy of Sciences,researchers report long-term monitoring of krill and penguins in the South Shetland Islands and data from other sites throughout the Scotia Sea and the West Antarctic Peninsula, the northernmost finger of the Antarctic continent.