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Whale Migration
The Long Journey

Written by: Laura Rose, Virginia Sea Grant, Virginia Institute of Marine Science
Credits: WhaleNet

Grade Level:
8-12

Lesson Time:
1 hr.

Materials Required:
blank map, 1997 sightings map

Natl. Science Standards
Click here for a list of the aligned National Science Education Standards.

Related Resources
Marine mammal, Endangered species

Summary
Track right whale migration in the Atlantic using data from WhaleNet.

Objectives

  • Identify the biological causes behind whale migration.
  • Discuss disruptions to whale migration, and the impacts of these disruptions.
  • Map and predict whale sightings and compare locations among years.

Vocabulary
Baleen whales

Introduction
Bears hibernate, whales migrate. Winter has arrived, and for many species of whales the season signals the annual trip to their breeding grounds. All baleen and many toothed species are migratory. Some species, like the humpback, the gray whale, and the Northern right whale, have well known migration patterns because they are close to shore in both summer and winter. Other species, like the fin, blue, and minke whales, head out into the open ocean in winter and are harder to find. Some whales still elude scientists for almost six months of the year!

In the summer, whales live in northern waters where their food is abundant. They build up their blubber for the long migratory journey because the food supply is scarce in the southern waters where they bear their young. Whales must give birth in warmer waters because their calves' blubber is not sufficient to insulate them from the colder waters. After 2-3 months of care and nourishment, the calves are ready to make the long journey north with their parents. Unfortunately, it is natural that some mortalities occur during such an arduous trip.

The California gray whales make the longest annual migration of all marine mammals, a round-trip journey of 10,000-12,000 miles. Their journey begins in the Chukchi and Bering Seas. From October to February they are traveling south to Baja, and then from February to July they make the trip home again. Last year their mortality rate was higher than normal, with more adults dying than normal. It is possible that these adults didn't get enough food to sustain them for the length of their travels because their food supply may have diminished. Researchers have noticed changes in the food chain in the Bering Sea which may be part of an even larger disruption of ocean temperature and biomass patterns. Such changes can have far-reaching implications. Visit the gray whale migration route and explore observation posts along the way.

The Northern right whale is one of the most critically endangered marine mammals with perhaps only 300 remaining in the North Atlantic. Part of their habitat is transversed by shipping lanes, and since the right whales are so slow and float much of the time, they are most threatened by collisions with ships. The National Marine Fisheries Service designated an area off the Florida and Georgia coast that includes the right whales' calving grounds as a critical habitat for the migratory whales. The Northern Right Whale Monitoring Project uses existing Navy technology to detect, identify, and track Northern right whales within the designated critical habitat. A report of a right whale is sent to an Early Warning System, which warns all ships in the area so they can avoid the animals.

Data Activity
Enter the WhaleNet Early Warning System Surveys for Right Whales in the Florida/Georgia area.
1. Click on 2005-2006. There you will find right whale sightings data.
2. Select the 2005-2006 Right Whale Sightings-Northern Right Whale Project link. The latitude and longitude for each sighting are given in columns F and G (respectively).
3. Print a map on which to plot your sightings. Next to each data point sighting on your map, make a note of how many adults and how many calves were sighted (columns I and J).
4. Print out the 1997 sightings map.

Discussion Questions:
1. How were the whales distributed? Were most whales seen in the same places?
2. Were the whales traveling alone or in groups? How many sightings included calves?
3. How did the sighting maps from 2005-2006 and 1996-1997 differ?

For more related activities and questions, see WhaleNet's follow-up questions.

You can also follow along with the Journey North site and track the spring return journeys of humpback, gray, and right whales. News of sightings were posted weekly, and the site provides challenge questions as well as answers from experts.

 The Bridge is sponsored by NOAA Sea Grant and the National Marine Educators Association

Virginia Sea Grant Marine Advisory Program
Virginia Institute of Marine Science
College of William and Mary