Image Credit: Y Ropert-Coudert/CNRS/IPEV via The Gaurdian
By Eva Gruber
Adelie penguins (Pygoscelis adeliae) are one of the most familiar, and most abundant penguin species on the planet, with an estimated 3.71 million breeding pairs. They are a true Antarctic penguin, found along the entire coast of the continent. They have 251 breeding colonies, where thousands (up to 300,000 individuals) will breed and nest from October to February. This is a short and strict breeding season, Adelies being under the harsh constraints of the brief Antarctic summer.
Notably, twenty years ago their population was 53% smaller. During that time, their population declined along with the Antarctic Peninsula, but at the same time, their population had increased in the East Antarctic. Now, Terre Adelie (“Adelie Land” in French) in the East Antarctic and home to 18,000 pairs, has suffered a devastating blow which will have consequences for the future stability of Adelie penguin populations. Biologists monitoring the colony were horrified as 99.9% of the chicks perished – the only survivors in the entire colony were two lone chicks.
The World Wildlife Fund has been supporting the penguin researchers from the French National Center for Scientific Research, who have been working in the region since 2010. Most of the Adelie penguin decline has been recorded along the Antarctic Peninsula. However, this year, unusually extensive sea ice covering their coast during the summer meant that the penguins had to travel farther to reach the ocean and forage for food for their chicks.
Adelie Penguins survive mostly on a diet of krill, who generally fare better with more sea ice. Sea ice encourages the growth of phytoplankton, which the krill feed on. However, even if this was a good krill year, the energy budget for Antarctic organisms is very tight. Many animals survive on the edge of starvation, and traveling further means expending more energy – perhaps more than the penguins “budgeted” for a foraging trip.
This kind of catastrophe is shocking, but seabird colony failures are becoming more common as climate change progresses. These abnormalities produce drastic and sudden ecological changes that can have serious impacts on ecological factors like food availability, temperature, precipitation, etc. Four years ago, no chicks survived when the rain hit the colony followed by a return to freezing temperatures – the chicks became soaked and then froze to death.
Researchers and conservation organizations such as the World Wildlife Fund are calling on policymakers to increase protection on the waters around East Antarctica. With protection from commercial krill fisheries, Adelie penguins could be given a chance to feed themselves and their chicks.
References:
https://www.ecowatch.com/penguin-breeding-starvation-2496295642.html
http://www.cnn.com/2017/10/13/world/antarctica-penguin-chicks-die/index.html