16 April 2015 A Closer Look at Migrations

Upcoming PolarConnect Event

Be sure to register for our upcoming PolarConnect Webinar on April 18th, 2015 at 1pm Pacific DST [12pm Alaska DST; 2pm Mountain DST; 3pm Central DST; 4pm Easter DST]! http://www.polartrec.com/polar-connect/register

It’s a free online event where Chief Scientist, Frank, and I will be talking about the research we've been doing and what life is like on the ship in Antarctica. Then we’ll open the talk up to answer your questions live. We hope you can join us!

If you are in Southern California, you can also head down to Cabrillo Marine Aquarium for their Earth Day and Bird Festival, for lots of great family fun, and a chance to listen to our webinar live in their Auditorium.

A Closer Look at Migrations

We’ve been seeing quite a few penguins (and some seals) on the sea ice. And at least for the emperor penguins, this is the time of year they’re on their big migration inland to breed. Finn, 1st grade, and Forrest, 2nd grade would like to take a closer look at animals migrating in Antarctica.

Not all Antarctic animals migrate. May invertebrates—from the few arthropods (bugs) on land to the echinoderms and sponges under the water—stay where they are year-round. However, there are many animals that do migrate, and there are a few different ways that these migrations occur.

Migrating to and from Antarctica

The most common form of migrating we tend to think about is going to and from a location, usually with the seasons. Some of Antarctica’s most famous migrating animals migrate to Antarctica during the summer to feed on the abundant plankton and fish and migrate away to avoid the cold, harsh winters.

Humpback whales migrate to Antarctic feeding grounds during the summer to feed on plankton and small schooling fish. As winter approaches, they leave for sub-tropical waters along the Eastern Australian coast to mate and give birth. This migration can be 12,000 to 16,000 miles per year!

Arctic terms are probably the most famous of the migrating animals. They have a circumpolar migration—meaning they fly from the Arctic to the Antarctic and back every year. That’s about 44,000 miles! The terns live in an endless summer, feeding in the North during the Arctic summer then heading south, making it to Antarctica in time for summer in the Southern hemisphere. That’s a huge trip to make for a bird that is only 25 inches across.

Migrating with the Sea Ice

Some animals stay in Antarctica year-round, but still have to migrate. As winter approaches, the sea ice around Antarctica can more than double, moving access to the water outward. As many marine animals depend on access to the ocean, they migrate yearly with the sea ice, staying close to the shoreline.

Penguins, like the Adélie and chinstrap penguins, move as sea ice grows. They migrate across the ice to get from their feeding areas to their breeding areas or to stay near the sea (depending on the time of year). Emperor penguins have an even further distance to travel to their breeding grounds. During the mating season, emperor penguins will walk 60 miles inland from the oceans edge to their breeding area. As sea ice grows in winter, this distance grows as well. By the peak ice formation, the emperor penguins can end up walking farther than 100 miles to reach the water.

Seals, like Weddell seals and crabeater seals stay near the water’s edge, moving inward or outward with the sea ice seasonally.

Migrating up and down in the ocean

Instead of going back and forth, some migrating animals go up and down. Antarctica’s rich ocean is home to many different types of plankton, many of which undergo a “diel vertical migration.” This means they migrate up and down in the water column with different times of the day. Many plankton, like copepods and krill, will move up toward the surface to feed at night then return to the deep during the day to rest and avoid predators. While this may only be several hundred feet, that’s a big migration for a tiny plankton! Because there are so many plankton in oceans across the world that make this migration, the diel vertical migration is sometimes known as the greatest migration in the world.