Climate change is altering the life cycles in Antarctica. In recent years, scientists have observed superagrupaciones over 300 humpback whales giving authentic feasts in the largest banks seen in Antarctic krill more than 20 years of observations.
sightings, made in ice-free waters in the middle of the austral autumn, suggest scientists who studied the low- Antarctic bays are important feeding areas of these endangered whales at the end of season. But they are also the mirror where you can see how quickly climate change is affecting the region.
A team of Duke University (USA) tracked this superagrupación of whales and krill during an expedition to Wilhelmina Bay six-week May 2009. The results of her research have been published in the latest issue of the scientific journal PLoS ONE. "
"Never has there been so incredibly dense grouping of whales and krill in this area and this time of year," said Douglas Nowacek, a scientist at Duke University.
Nowacek and his colleagues spotted 306 humpback whales, or put another way, 5.1 whales per square kilometer, the density is larger than ever recorded in Wilhelmina Bay Antarctica. The researchers measured krill biomass of approximately two million tons . In the waters just a few small pieces of ice floating covered less than 10% of the sea surface of the bay. The team returned to the area in May 2010 and again picked up similar numbers.
years ago, the ice used to cover almost the entire bay and fjords for the month of May, protecting krill and forcing the whales to migrate elsewhere to find food . But the advance of climate change in this area during the past 50 years has substantially reduced ice extent and delayed the onset of ice cover.
"The loss of sea ice is good news for whales in the short term, as tray serves authentic krill feast. But it is a long-term bad news for both species," says Ari Friedlaender, Marine Laboratory scientist at Duke University and lead author of the research. "This will have effects on the krill's ability to regenerate their own populations and, therefore, able to maintain populations of predators Antarctic krill-dependent."
Via: World
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