Alaska’s extensive coastline and nutrient-rich waters create a dynamic marine environment, supporting a diverse array of whale species. These waters serve as feeding grounds, migratory pathways, and sometimes breeding areas for cetaceans, ranging from the immense baleen whales to agile toothed predators.
Giants of the Alaskan Seas
Humpback whales are frequently observed in Alaskan waters, recognized by their long pectoral fins and distinct tail flukes. These baleen whales, reaching up to 60 feet and 40 tons, are known for acrobatic displays like breaching and tail-slapping. They use “bubble net feeding,” a cooperative hunting strategy where whales release bubbles to encircle fish before lunging to consume them. Humpbacks feed on krill, herring, and other small fish in Alaska during summer, migrating to warmer tropical waters for breeding.
Gray whales undertake one of the longest migrations of any mammal, traveling up to 14,000 miles annually between their feeding grounds in the Bering and Chukchi Seas and breeding lagoons in Baja California. These whales are primarily bottom feeders, using their baleen to filter small crustaceans and invertebrates from the seafloor. They often roll on their sides to scoop up sediment, leaving behind characteristic feeding pits. Gray whales are typically seen alone or in small groups, though large aggregations can form in feeding areas.
Fin whales, the second largest whale species after blue whales, are found in Alaskan waters. These sleek, fast swimmers can reach speeds up to 23 miles per hour. They are identified by their asymmetrical coloration, with a white lower right jaw and a dark gray lower left jaw. Fin whales feed on schooling fish, krill, and other crustaceans by gulping large swarms of prey while swimming on their sides. They are often seen in groups of 6-10 animals, but can form larger feeding aggregations.
Minke whales, the smallest of the baleen whales, are common summer visitors to Alaskan areas like Kachemak Bay, Glacier Bay, and Prince William Sound. They are characterized by their dark gray upper bodies, lighter undersides, and a distinctive white band on each flipper. Minke whales are fast swimmers and can be difficult to spot due to their quick, shallow surfacing and inconspicuous blow. They typically travel alone or in small groups and feed on schooling fish such as herring, cod, and mackerel, as well as copepods and euphausiids.
Predators and Social Whales
Orcas, commonly known as killer whales, are prominent toothed whales in Alaska, recognized by their black and white markings and tall dorsal fins, and live in complex social structures called pods. Alaskan orcas are categorized into three distinct ecotypes based on their diet and social behavior: residents, transients (also known as Bigg’s), and offshore orcas. Resident orcas primarily consume fish, including salmon, mackerel, and halibut, and form large, stable family groups. Transient orcas are mammal-eating specialists, preying on seals, sea lions, and even other whale species, typically traveling in smaller groups. Offshore orcas, less frequently sighted, are believed to feed on sharks and other fish, and usually occur in larger groups further from the coast.
Beluga whales are easily identified by their unique white coloration, which develops as they mature from gray calves. These social whales are often called “canaries of the sea” due to their wide range of vocalizations, including clicks, whistles, and grunts, used for communication, navigation, and hunting. Belugas prefer shallow coastal waters, bays, and estuaries, and can tolerate both salt and freshwater. They are found in five distinct populations across Alaska.
Sperm whales, the largest toothed whales, are present in Alaskan waters. Males are more commonly seen in higher latitudes, feeding on abundant prey. These whales are exceptional deep divers, capable of descending to depths exceeding 3,000 feet for over an hour in pursuit of squid, their primary food source. Their deep-diving behavior and reliance on echolocation make them challenging to study.
Infrequent Visitors and Deepwater Dwellers
Bowhead whales are adapted to Arctic and sub-Arctic environments, spending their entire lives amidst sea ice in the Bering, Chukchi, and Beaufort Seas. They possess an extremely thick blubber layer, up to 1.6 feet, for insulation and can break through ice up to 2 feet thick with their massive, bow-shaped skulls to create breathing holes. Historically, bowheads were a target for commercial whaling, leading to significant population declines.
Sei whales are less common in Alaskan waters compared to other baleen species, preferring deeper offshore areas. These fast swimmers feed on copepods, krill, and small schooling fish.
Blue whales, the largest animals on Earth, are rare visitors to Alaska. These immense whales, reaching up to 100 feet in length, are migratory and primarily feed on krill.