You may have read it in the news the past week, in Terre Adelie, an Adelie penguin colony with 18.000 breeding pairs only managed to raise two chicks last season. Two, out of approximately 36.000 attempts as they usually produce two eggs per pair. Most of the birds have died of starvation. Reason for this is the longer distance the parents had to travel to the edge of the sea ice where they could find food. Due to local changes in the environment this part of Antarctica sees an increase in sea ice extent the past years. As Adelie Penguins only breed on solid ground but feed along the ice edge the distance they had to travel to their feeding grounds had increased, which apparently meant they couldn’t bring enough food to the colony, causing most of the chicks to die of starvation.
Adelie Penguins are the southernmost breeding penguin species in the world. They breed even further south as the Emperor Penguins. They very depend on sea ice to find their food. Any changes in sea ice coverage can be fatal for them. An increase, as seen in the Terre Adelie, can mean the distance to the feeding grounds gets too long. But a decrease in sea ice extent will have significant impacts on the ecosystem they are part of, possibly resulting in a loss of food sources.
At the moment the relationship between Antarctic sea ice extent and climate change is not very well understood. In recent years, most of Antarctica has seen an increase in sea ice extent. Possibly due to an influx of fresh water from the melting glaciers, which changes the freezing temperature of the water. Another possibility is that stronger winds in the Southern Ocean result in stronger Coriolis forces, pushing the ice further north, with the now open southern parts freezing again. However, the previous year saw a very low sea ice extent. On the Antarctic Peninsula, an area with a rapid decline in sea ice extent, the number of Adelie Penguins drops rapidly. Their niche is taken over by the, less ice-depending, Gentoo and Chinstrap Penguins.
All in all is the Adelie Penguin definitely a species to watch out for. Apart from climate change is the krill fishery also a possible threat to them. This week the 24 nations + EU, who form CCAMLR come together again in Australia to discuss further plans to protect the seas around Antarctica. Even though they can’t stop climate change, the protection of these areas from all sorts of fisheries is definitely a good thing that will help to protect this adorable penguin.