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Tiger sharks serve as mobile oceanographers in UH research

By Staff | May 7, 2020

Experts tag a tiger shark with a tracking device in waters off of Maui. PHOTO BY HIMB.

HONOLULU – University of Hawaii at Manoa researchers attach satellite tags to the dorsal fin of tiger sharks to collect oceanographic data, follow movement patterns and discover their preferred habitat in Hawaiian waters.

The project is led by UH Manoa Research Professor Kim Holland and his team at the Hawaii Institute of Marine Biology.

Sharks are tagged in waters off of Oahu and Maui. When a tagged tiger shark comes to the water’s surface, the tag’s antenna will transmit the data collected via satellite and land-based stations.

The data feeds into oceanographic and meteorological models, which will improve weather forecasting and provide more understanding of how the ocean is rapidly changing, Holland explained.

“Sharks play an extremely important role in the world’s ecosystems. So it’s really important for us to know what habitats they choose, how far they go, what their behavior is,” he said.

A tiger shark in Hawaii with the latest generation of satellite tag. PHOTO BY MARK ROYER.

Tags work as small computers, measuring ocean depth, temperature, salinity, dissolved oxygen and light levels.

“So we’re trying to increase the amount of science that we can get out of these tracking experiments by employing this new generation of tags,” Holland said, “which tells us not only where the shark is going and how deep it is, but also is telling us about its environment.”

“So that this will improve weather forecasting – it will improve our understanding of how the ocean is rapidly changing. We can provide data on a much denser, more frequent basis than traditional oceanography can.”

Researchers prefer to work with tiger sharks, so they can study their behavior and the impact on human safety.

Tiger sharks are easy to work with when they are flipped over, because they enter into a temporary state of inactivity called tonic immobility, making it easier to attach the tag.

Holland hopes the research will expand to other species, like blue sharks and hammerhead sharks, which travel to other parts of the ocean and have different diving patterns.

The Pacific Islands Ocean Observing System (based at UH Manoa) and the Integrated Ocean Observing System are in the process of making the oceanographic data available through the Animal Telemetry Network.