Humpback whales live in every major ocean basin on Earth, from Arctic feeding waters to tropical breeding lagoons. They are among the most wide-ranging mammals on the planet, with some populations swimming 5,000 miles each way between summer and winter grounds. Where you’ll find them at any given time depends almost entirely on the season.
The Seasonal Pattern: Cold Water to Warm Water
Humpback whales split their year between two very different habitats. In summer, they feed in cold, nutrient-rich waters near the poles. In winter, they migrate to warm, shallow coastal waters in the tropics to mate and give birth. Breeding and calving grounds generally fall within a water temperature range of 21 to 28°C (roughly 70 to 82°F), and mothers prefer areas near offshore reefs or close to shore where the water is calm and shallow.
This back-and-forth migration is one of the longest of any mammal. Populations in both the Northern and Southern Hemispheres follow this pattern, though their seasons are reversed: when it’s summer in the North Atlantic, humpbacks there are feeding, while humpbacks in the Southern Hemisphere are on their tropical breeding grounds during the austral winter (June through September).
North Pacific Populations
The North Pacific hosts several distinct populations, each with its own winter breeding destination. One group breeds along the Pacific coast of Mexico and the Revillagigedo Islands. Another breeds along the coasts of Central American countries including Costa Rica, Panama, Guatemala, El Salvador, Honduras, and Nicaragua. A third population winters in the main Hawaiian Islands, where humpbacks are generally present from November through April, with peak numbers between January and March. The whales concentrate around Penguin Bank, the Maui Nui region (Maui, Lānaʻi, Molokaʻi, and Kahoʻolawe), Kauaʻi, Niʻihau, Hawaiʻi Island, and Oʻahu.
On the western side of the Pacific, a separate population breeds near Okinawa, Japan, and the Philippines. All of these groups travel north in summer to feed in the colder waters off Alaska, British Columbia, and the broader North Pacific.
North Atlantic Populations
In the North Atlantic, humpbacks feed during spring, summer, and fall across a stretch of ocean from New England to Iceland, Norway, and beyond. One of the best-known gathering spots is Stellwagen Bank, a shallow underwater plateau off the coast of Massachusetts. Around 900 humpbacks visit Stellwagen Bank each year, drawn by enormous schools of sand lance, a small, pencil-shaped fish packed with fat. Sand lance thrive in the sandy sediment of the bank, and the whales, along with seabirds and other predators, follow wherever those fish concentrate.
When fall arrives, North Atlantic humpbacks head south. The two main winter destinations are the West Indies, particularly the waters around the Dominican Republic, and the waters off Cape Verde near the west coast of Africa. The Dominican Republic’s warm, sheltered bays serve as a primary calving ground for whales that spent the summer feeding in the Gulf of Maine.
Southern Hemisphere Breeding Stocks
The Southern Hemisphere has an even more complex picture. The International Whaling Commission recognizes seven distinct breeding stocks, labeled A through G, spread along continental coastlines.
- Stock A winters off the coast of Brazil and migrates south to feeding grounds near South Georgia and the Antarctic Peninsula.
- Stock B is split into two substocks: B1 breeds in the Gulf of Guinea (West Africa), while B2 uses the west coast of southern Africa as a feeding area.
- Stock C includes four substocks breeding along the east coast of Africa and the western Indian Ocean, with groups off Mozambique, in the central Mozambique Channel, along southeast Madagascar, and around the Mascarene Islands.
Additional stocks (D through G) occupy breeding grounds across the remainder of the Indian Ocean, around Australia, and throughout the South Pacific. All Southern Hemisphere stocks feed in the frigid, krill-rich waters surrounding Antarctica during the austral summer (December through March).
The Arabian Sea: A Population That Never Migrates
Nearly every humpback whale population on Earth migrates. The one striking exception lives in the Arabian Sea, off the coast of Oman. This small group stays in the region year-round, making it the world’s most isolated and genetically distinct humpback whale population. Genetic analysis suggests it split from Southern Indian Ocean whales roughly 70,000 years ago and has had little or no contact with other populations since.
The evidence for their isolation is layered. No whale photographed in Oman has ever been matched to research catalogs in Madagascar, South Africa, Mozambique, or Zanzibar. Their songs are completely different from those recorded in nearby regions. They carry fewer barnacles and lack the circular bite scars from cookiecutter sharks that are common on Southern Hemisphere humpbacks, further confirming they don’t travel into those waters. Some individuals move seasonally between areas along the Omani coast, from the Hallaniyat Islands in late winter and spring to the Gulf of Masirah in autumn, but they never leave the broader Arabian Sea region.
This population is tiny. A mark-recapture study conducted between 2000 and 2004 estimated just 82 individuals. While humpback whales globally are classified as “Least Concern” by the IUCN, the Arabian Sea population is listed as “Endangered.”
Where Climate Change Fits In
Humpback whale breeding grounds are tightly linked to a specific temperature window of 21 to 28°C. As ocean temperatures rise, some of those coastal breeding areas could warm beyond that range, potentially pushing whales into deeper waters farther from shore or shifting their migration timing. On the feeding end, research from institutions including Woods Hole Oceanographic Institution has found that climate change may reduce sand lance availability in the Gulf of Maine, which could affect food supply at key sites like Stellwagen Bank. Because humpbacks go wherever their prey concentrates, changes in prey distribution could reshape the map of where these whales are found in the coming decades.