Research shows Adélie penguins must balance the benefits and costs of navigating sea ice during long-distance migrations

Research by Point Blue Conservation Science, a Petaluma-based nonprofit, shows how Adélie penguins in Antarctica’s Ross Sea use sea ice during their annual migrations. The article titled “Following the pack ice: Sea ice movement affects distance and destination during winter movements of Adélie penguins” is published in the journal Ecology.

Adélie penguins, although flightless, can undertake extraordinary migrations like their flying relatives, traveling thousands of miles to sea from their terrestrial breeding colonies in Antarctica, following daylight and food through the long winter Antarctic.

Many other species are known to use wind or ocean currents to help them conserve energy when traveling, but until now relatively little is known about whether and how Adélies could use the movement of sea ice to support their movements.

Understanding this interaction can provide new insights into ecology and conservation, especially as long-term monitoring has revealed record levels of sea ice extent and concentration in Antarctica and the Ross Sea in the over the last 10 years.

Point Blue has been studying Adélie penguins on Antarctica’s Ross Island since 1996. Recent advances in the miniaturization of electronic tags have allowed researchers to track the winter movements of 87 individuals during 146 voyages spanning three years .

Point Blue’s Dennis Jongsomjit, lead author of the study, noted: “Combining these new tracking beacons with remotely sensed satellite data on sea ice movement means we have been able to study in more detail than ever before previously if and how Adélie penguins interacted with sea ice.

The study found that Adélie penguins travel greater distances when they receive more support from moving sea ice. However, penguins can also be hampered by sea ice, with slower movement speeds when moving against the prevailing ice drift.

As ice speeds increased, penguins were found further north, indicating the need to balance the benefits and costs of sea ice navigation. Variations and changes in sea ice movement may serve as a mechanism impacting adult survival and reproductive success, thereby helping to drive population trajectories on Ross Island.

The study also highlights the interdependence of various species in the Southern Ocean, with ocean and sea ice currents influencing not only penguins, but also the life histories of other species they interact with, such as krill, silverfish and Antarctic toothfish.

“As climate change alters sea ice patterns,” Jongsomjit added, “this could impact the energetic costs of migration, breeding success and population dynamics of Adélie penguins, as well as on the global ecology of one of the most pristine ecosystems on the planet.