Marine mammals and birds we saw in Antarctica

There are many reasons to go to Antarctica, but probably the main draw is the marine life, especially penguins. I’ve already done a post about penguins (https://landscapes-revealed.net/gentoo-penguins-on-the-antarctica-peninsula/), but many more important life forms reside there.

This post has images and—now that I’m home with more band width—videos of marine mammals and seabirds, including the flightless birds—penguins. Krill is the keystone species supporting the abundant forms of life, but this food source is being threatened. We’ll look at why.

Whales

Orcas, a type of toothed whale commonly known as killer whales, live in Antarctica but we did not see any around the Antarctica Peninsula. We did see numerous baleen whales, notably a large number of humpbacks. These baleen whales filter small prey like krill and fish through their baleen plates, consuming massive quantities each day during the feeding season.

There are two populations of humpbacks. Northern Humpbacks feed in coastal waters off British Columbia and Alaska—we’ve seen them bubble feeding off the coast near Juneau—and migrate to warmer tropical breeding grounds around Hawaii, Mexico and Central America. Southern Humpbacks migrate from their summer feeding grounds in Antarctica—where we saw them—to breeding areas in the South Pacific around Australia and New Zealand.

Pinnipeds (Latin for fin-footed)

Pinnipeds are a group of marine mammals that includes seals, sea lions, and walruses. They are characterized by fin-like limbs that enable them to move around on land and streamlined bodies that make them efficient swimmers.

Seabirds

Birds we observed along the Antarctica Peninsula were a variety of petrels, gulls, terns, skuas, shags (like cormorants) and sheathbills. The most common birds were the flightless penguins that I’ll show in a separate section.

Penguins

At the top of this page is a link to my post about Gentoo penguins, the type we saw the most. On our last expedition day, we were fortunate to have bright sun and views of another type of penguin colony—the chinstraps. It’s easy to see why they have this name.

The essential krill food

Krill is a general term for a group of small shrimp-like crustaceans found throughout the world’s open oceans. Antarctic krill is a species in the Southern Ocean that provides the basis of the diet for most marine mammals and seabirds. Antarctic krill are economically important, as they sustain the largest fishery in the Southern Ocean.

However, Antarctic krill populations are threatened. The combined effects of ocean warming, sea ice loss and ocean acidification are negatively impacting krill survival and reproduction. This article describes an NSF-funded project that is studying the climate impacts: https://www.nsf.gov/science-matters/antarctic-krill-superheroes-southern-ocean. On top of that, the krill fishing harvest is further depleting the population.

Once back home, Ralf came upon an article explaining that the Sea Shepherd is an environmental organization that campaigns against exploiting the oceans. They were in Antarctica to monitor the boats that compete to get the biggest and most lucrative share of the 620,000-ton limit that is set by an intergovernmental body. The trade is legal, but there is evidence that krill fishing is having a negative impact on the Antarctic food web.

To read more about the Sea Shepherd and its effects, see this article in the Guardian: https://www.theguardian.com/environment/2026/mar/24/krill-foundation-food-antarctic-ecosystem-survive-factory-fishing. This link is to the Sea Shepherd’s web site that further explains their activities: https://seashepherd.org/2026/02/20/antarctica-krill-whale-feeding-grounds-2026/.

A closing peaceful view