Penguins, who were once present in large numbers such as 8 millions have drastically fallen down to 2 – 3 million thanks to low availability of food caused by the changing climate and melting ice.
The study pointed out “Young Penguins are dying” because of low availability of the penguin food “krill”
What is Krill?
As reported via Wikipedia, Krill is the common name given to shrimp-like marine crustaceans. These small invertebrates are found in all oceans of the world. The common name krill comes from the Norwegian word krill meaning “young fry of fish”, which is also often attributed to other species of fish.
Krill are considered an important trophic connection—near the bottom of the food chain—because they feed on phytoplankton and to a lesser extent zooplankton, converting these into a form suitable for many larger animals for whom krill makes up the largest part of their diet.
Krill is mostly eaten by whales, seals, penguins, squid and fish.
What has krill got to do with Penguin declination?
Krill, as explained above, is the most preferable food for the penguins living in the Antarctic.
Krill needs ice to survive, and as climate change causes more polar sea ice to melt, the tiny sea creatures cannot breed or feast on phytoplankton in the ice and their numbers fall, taking away an important source of nourishment for penguins.
Also, Krill has been eaten in large quantities by whales that add to the decline factor
What does the US Study really says?
The study focuses on Chinstrap Penguins and Adelie Penguins.
Chinstrap penguins, known for their characteristic head markings that resemble a cap with a black line just under the neck, are the second largest group in the area after the macaroni penguins, and are at particular risk because their population is restricted to one area, the South Shetland Islands.
“It is a dramatic change,” says lead researcher Wayne Trivelpiece, of the National Oceanic and Atmospheric Administration’s Antarctic Ecosystem Research Division
“There are still two to three million chinstrap pairs in this region but there were seven to eight million two decades ago,” he said.
Trivelpiece, the co-author on a study published in 1992, suggested that penguin populations were surging and subsiding according to changes in sea ice — with the chinstrap doing better in warm years and the Adelie thriving in cold years.
But now, Trivelpiece goes on to say that Krill is the real enemy for the decline of Penguins. As Krill decreased, so does Penguin because they run out of food supply.
“Under a scenario of global warming and increasing temperature we had prophesized that Adelies and ice-loving animals like Adelies should decline while chinstraps and ice-avoiding animals should increase,” Trivelpiece said.
But shortly after the team’s paper was published in the early 90s, the data began to change.
“From that point shortly thereafter onward, we lost those large fluxes and both species started behaving the same way and both started declining dramatically,” he said.
“By the time we had enough data to realize what was going on with the youngsters, we realized that the big difference was between the early years when there was a lot of krill around, and the later years when there wasn’t.”
Over the past three decades, krill biomass has declined 38 to 81 percent, said the study.
“If warming continues, winter sea-ice may disappear from much of this region and exacerbate krill and penguin declines,” it said.
The Study concluded with the recommendation to keep the Penguin species (especially Chinstrap Penguins) in Red List of vulnerable species
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