Visit Your Local PBS Station PBS Home PBS Home Programs A-Z TV Schedules Watch Video Donate Shop PBS Search PBS
SAF Archives  search ask the scientists in the classroom cool science

Guide Index

Polar Bear Picnic

The Wilder, the Better

Doctor Fish

Tuna in the Tank

Zoos as Arks

Return to the Wild

Viewer Challenge
in the classroom

The New Zoos: Tuna in the Tank

Keeping fish healthy and happy is just one goal of the Outer Bay exhibit at California's Monterey Bay Aquarium. Rescuing fish and marine animals from extinction is a critical priority. One species being studied is the world's most prized and endangered fish, the giant bluefin tuna. Thanks to knowledge gained from other tuna in captivity, an ambitious world-wide program to track and save this fish has a greater chance of success.

Curriculum Links
Related Frontiers Shows and Activities
Activity: Play a Tracking Game







animal behavior


tracking devices



With prices up to $90,000 for one fish, the Atlantic bluefin tuna is considered the world's most valuable fish. It's also one of the world's most endangered.

To understand why the population is declining, biologists from the National Marine Fisheries Service, the Monterey Bay Aquarium and Stanford University began tracking the migration of bluefin tuna in 1996. Scientists are collecting data on migratory routes and spawning areas, which will help answer critical questions about the bluefin tuna.

The transoceanic migration of bluefin tuna takes them from the Atlantic Ocean off New England as far north as Norway and as far south as Brazil. Researchers are tracking tuna using computers and high-tech archival tags -- electronic data-logging devices. In this activity, you can use low-tech methods to track a teacher or student.


Define the range of an individual based on observations made over the course of a day.

  1. Construct a large map of your school or campus and mount it on the wall of your room. This is the map you will use to post tracking information.

  2. A teacher or student should volunteer to be tracked for one day. This individual must agree to keep a log for the day showing his or her movements. Have the person being tracked pin a "tag" (a piece of bright ribbon) on his or her book bag or backpack. Part of the exercise is to see if other students can spot the tag of the person being tracked, so the person's identity should be kept secret.

  3. Designate one full day to track the individual. Throughout the day, students will record sightings of the tagged individual. Each student should keep a log for the day of the tracking game. Write down the time, duration and location of sightings.

  4. The next day in class, compile all the sighting data on the class map.

  5. Compare the sightings made by your class with the log kept by the tagged individual.
  1. How effective was your tracking effort at defining the places visited by the person being tracked?

  2. How could you improve the accuracy of your tracking?

  3. You observed your subject in a limited area. Is this an accurate reflection of the area where he or she might move about in a day? A week? A month?

  1. Research the tuna's migration paths and plot them on a world map.

  2. Researchers tracking the tuna use a tag that sends information about the tuna's location to a satellite, and is then communicated to the research team. Have the person being tracked write down time and location hints on pieces of paper or Post-it notes and place them in various places throughout the school. See if these "sightings" improve the tracking information.

  3. In recognition of the importance of the marine environment, the United Nations has designated 1998 the "International Year of the Ocean." As a related project, research the status, overfishing and decline of the bluefin tuna.

  4. For more on the tuna tracking project, consult this Web site: the Monterey Bay Aquarium.

  5. Investigate why the bluefin tuna is considered warm-blooded. To learn more about the bluefin tuna, visit Saving the Bluefin.


Scientific American Frontiers
Fall 1990 to Spring 2000
Sponsored by GTE Corporation,
now a part of Verizon Communications Inc.