Many baleen whales and some toothed whales (e.g., male sperm whales) travel thousands of miles between higher latitude feeding areas and lower latitude areas for breeding and calving purposes. For these nomadic whales, their home is as vast as the ocean itself, and the only boundaries that exist, are the places where land meets the sea.
Our understanding of the distribution and migrations of whales comes from whaling era records, individual identification of whales photographed in different locations, and more recent advances in radio and satellite telemetry.
Humpback whales make one of the longest migrations of any mammal, migrating as far as 5,000 miles, or 8700 km one-way between productive high-latitude summer feeding areas and lower latitude breeding grounds. Similar to some but not all other species of baleen whales, humpback whales undergo prolonged periods of fasting and have completely separated feeding from breeding and calving activities during the winter.
Undergoing extensive annual migrations, humpback whales are found throughout the world's oceans. In the North Pacific, humpbacks feed from Northern California to British Columbia, Alaska, the Aleutian Islands and Kamchatka Peninsula and migrate to Hawaii, Mexico, Japan, Costa Rica, and the Philippines for mating and calving purposes (see map). In the North Atlantic, humpback whales feed from the Gulf of Maine through Newfoundland, Labrador, Greenland, Iceland and Norway and migrate primarily to the West Indies, where they mate and calve. In the Southern Hemisphere, humpbacks feed in circum-polar waters around Antarctica and then migrate north to warmer waters for mating and calving.
It has been estimated that humpback whales need to eat as much as one ton of food a day to survive the winter fasting period!
Humpback whales feed in higher latitudes (40-60 degrees) each spring, summer and fall, and undergo prolonged periods of fasting during the winter. During the summer, the long days of sunlight combine with dissolved nutrients to produce dense swarms of plankton, creating seasonally rich and productive waters that the whales rely on for food. A humpback's diet consists of shrimp-like crustaceans called krill (euphausiids) and various types of small schooling fish, including herring, capelin, sand lance and mackerel.
Since lower latitude breeding areas are generally nutrient poor, humpback whales eat huge quantities of food each day during months where food is abundant in order to store energy in the form of blubber for the winter. In the North Pacific, humpback whales feed in waters off California, Oregon, Washington, as well as throughout British Columbia, Alaska, the Aleutian Islands, and Kamchatka Peninsula.
Whale breaching with West Maui mountains in the background.
During the winter, humpback whales assemble in lower latitude sub-tropical or tropical waters to mate and to calve. Although researchers still don’t understand why whales migrate to these winter grounds, it appears to be more for physical than biological characteristics. Most breeding grounds are warmer, shallower, and more protected than summer feeding areas, which may offer increased protection for mothers and their newborn calves. The dense congregation of whales that assemble in these winter grounds also brings together males and females, who may feed in different areas during the summer.
Spouting whales with West Maui mountains in the background.
Although in the North Pacific humpback whales are known to assemble in five different areas during the winter (see map from above), individual whales may move between different breeding grounds. For instance, humpback whales seen in Mexico one year have been seen in Hawaii the next year. On one occasion, a humpback whale was seen in Mexico and Hawaii during the same winter.
The Hawaiian Islands comprise the largest known reproductive assembly of humpback whales in the North Pacific Ocean, with an estimated four to six thousand whales visiting each year. Humpback whales are distributed throughout the waters around Hawaii, but the highest concentration of whales occur in the four-island region of Maui, Molokai, Lanai, and Kahoolawe, and an area known as Penguin Banks, a shallow bank between Molokai and Lanai. The sea conditions in Hawaii, including calm lees protected from trade winds, clear, warm water, and easy access to humpback whales make the Hawaiian Islands one of the best natural laboratories in the world to study whales.
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