STAR-BULLETIN / JUNE 2001 Scientists are using transmitters like this one to track and study the behavior of marine animals.

High-tech tags give
scientists tools to track
sea animal movement

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By Helen Altonn
haltonn@starbulletin.com

Scientists are seeing the ocean through the eyes of seals, whales, turtles and other marine life via a variety of high-tech tags and sensors.

"It's an innovative approach to studying the movements and habits of large pelagic animals ... to send out fleets of (tagged) animals and see the ocean from their perspective," said Jeffrey Polovina of the Honolulu Laboratory, National Marine Fisheries Service.

Polovina and other scientists discussed new tools to study marine animals in their home waters at international Ocean Science meetings in Honolulu last week.

Programs are developing to use new electronic technology to follow animals in the ocean and learn what they do, said George Boehlert of the Pacific Fisheries Environmental Laboratory in Pacific Grove, Calif.

A 10-year international research program, called Census of Marine Life (CoML), plans to investigate the diversity, distribution and abundance of marine organisms throughout world oceans, he said.

"The CoML will enable scientists to compare what once lived in the oceans to what lives there now, and to project what will live there in the future," Boehlert said.

A new class of electronic tags, small microprocessor-based units that can record information on the animals' migrations and ocean conditions, will be used in two pilot projects, he said.

Pacific bluefin tuna, elephant seals, albatross, leatherback sea turtles, sharks and whales will be released simultaneously in the Tagging of Pacific Pelagics project to learn how they migrate and seek food.

In a Pacific Ocean Salmon Tracking project, acoustic sensors on young salmon will send signals to listening stations to track movements of adult salmon in the open ocean.

"We don't really have good information on where salmon go and what they do when they're out there," Boehlert said.

Use of electronic sensors on migratory animals have shown they are more wide-ranging than formerly believed but feed primarily in specific areas.

Some animals must be recovered to retrieve data, but with some technology the tag pops off, floats to the surface and relays data via satellite to researchers, Polovina said.

Data from tagged elephant seals show they cover most of the Pacific Ocean and spend 90 percent of their time under the surface at depths of 900 to 2,000 feet, said Daniel Costa, ecology evolutionary biologist with the Long Marine Laboratory in Santa Cruz, Calif.

Bruce Mate and his colleagues at the Hatfield Marine Science Center at Oregon State University tagged 100 blue whales off California's coast and found the animals -- as large as 100 feet long and weighing up to 100 tons -- travel much farther and faster than it was believed.

The new technology enables scientists to collect data on up to 20 whales and other species simultaneously for four to five months, Mate said. In the past, they had to follow each tagged whale by boat and could only go as far as the signal -- five miles, he said.