Marine Mammals

Marine mammals are found all along the Alaskan coast, from Ketchikan [1] in the Southeast to Barrow on the Arctic Ocean. Sea otters are frequently found in harbors, bays, and inlets, particularly around kelp beds.

Good places to look for whales, seals, sea otters, sea lions, porpoises, and other marine mammals are the Inside Passage [2], Prince William Sound [3], Kodiak Island, Kachemak Bay [4], and Kenai Fjords [5].

The Pribilof Islands serve as rearing and resting areas for thousands of northern fur seals, harbor seals, Steller sea lions, and walrus in the summer. Only Native Alaskans have the legal right to hunt marine mammals.

An Endangered Ecosystem?

In the last several decades, scientists have watched with increasing alarm as marine mammal populations plummeted in the North Pacific and the Bering Sea, particularly around the Aleutian Islands. Environmentalists blamed overfishing of pollock, while fishermen pointed the finger at long-term changes in ocean currents and temperatures. But recent evidence points in a different direction—whaling.

After World War II, Japanese and Russian whalers developed lethal ways to hunt bowhead, sperm, and humpback whales, killing at least 500,000 of them before commercial whaling ended in the 1970s. These giant whales formed an important part of the diet for killer whales, and without this, the orcas turned to other food sources.

As top predator in the ocean, killer whales apparently worked their way across the food chain, attacking fur and harbor seals in the 1970s, Steller sea lions in the 1980s and 1990s, and most recently an animal with very little meat, sea otters.

If this is indeed the cause for the decline of these marine mammals, there is little that can be done to halt the damage. Overfishing (or in this case overwhaling) can have disastrous consequences for the oceans, and for animals and humans that depend on the fish.

The effects of commercial whaling continue to ripple through the ecosystem, but other problems pose even more serious threats in northern seas. Global warming is a particular problem for ice-dependent marine mammals such as walrus, ringed seals, spotted seals, and bearded seals. As Arctic ice retreats, the animals lose places to rest, give birth, and rear pups. In addition, polar bears (technically a marine mammal) are increasingly threatened by the loss of sea ice and the seals that provide food.

Ocean acidification has only recently been viewed as a serious problem. As the oceans absorb human-caused carbon dioxide, their pH decreases. If it drops too far, organisms such as clams, mussels, corals, and crabs are unable to form shells. In addition, many planktonic animals that provide food for salmon and other fish cannot survive, causing problems farther up the food chain. Learn more from the Alaska Marine Conservation Council (www.akmarine.org [6]).