This illustration displays the winter migration patterns of blue whales in the North Pacific Ocean.

Map by Hiram Henriquez, Lisa R. Ritter, and A.R. Williams
  • From the map above:

    North Pacific blue whales were known to winter at the Costa Rica Dome, a nutrient-rich upwelling that supports abundant krill. But its location shifts, so scientists aboard the Pacific Storm research vessel used satellite tagged whales to lead the way. Three of the 15 whales tagged off Santa Barbara made the migration in early 2008. Others wintered off Mexico.

    1. How many blue whales were tagged in this migration study?

      Six whales were tagged.

    2. Two whales were tagged at the nutrient-rich Costa Rica Dome, off the west coast of Central America. Where were the other whales tagged?

      The other whales were tagged off the coast of the U.S. state of California. Three were tagged near Santa Barbara, and one further north.

    3. Approximately how far did the whales tagged near Santa Barbara migrate to reach the Costa Rica Dome?

      The Santa Barbara whales migrated about 3,200 kilometers (2,000 miles) to the Costa Rica Dome.

    4. Based on the graphic at the bottom of this map, how long does a blue whale hold its breath while feeding?

      Whales feeding around the Costa Rica Dome hold their breath for about 15 minutes.

    5. The text on this map says that blue whales spend their winters at the Costa Rica Dome. The area has an abundant supply of krill, blue whales' primary food source. Besides eating, what do you think the whales do near the Costa Rica Dome?

      Answers will vary. The warm waters off Central America are an ideal place for female blue whales to give birth.

  • Term Part of Speech Definition Encyclopedic Entry
    animal migration Noun

    process where a community of animals leaves a habitat for part of the year or part of their lives, and moves to habitats that are more hospitable.

    blue whale Noun

    species of marine mammal that is the largest animal to have ever lived.

    echo sounder Noun

    device that measures the depth of water using sound pulses. Also called a sonic depth finder.

    krill Noun

    small marine crustacean, similar to shrimp.

    nutrient Noun

    substance an organism needs for energy, growth, and life.

    Encyclopedic Entry: nutrient
    research vessel Noun

    ship or boat equipped to carry out scientific experiments or collect data.

    satellite tag Noun

    device attached to animals that can track their movement using satellites and GPS technology.

    upwelling Noun

    process in which cold, nutrient-rich water from the bottom of an ocean basin or lake is brought to the surface due to atmospheric effects such as the Coriolis force or wind.

    Encyclopedic Entry: upwelling