Rays Don't Stray: Giant Mantas Stick Close to Home

By Mindy Weisberger, Senior Writer | June 20, 2016 02:01pm ET

Until recently, manta rays — which sail through tropical and temperate ocean waters, looking much like enormous kites — were thought to migrate great distances across ocean basins, as do many of the largest marine animals.

But a new study finds that these big fish have a much smaller range than scientists had thought.

Researchers investigated data gathered from tracking devices on the manta rays, as well as chemical and DNA analysis  of the rays' muscle tissues. The scientists were surprised to find that these giants of the deep are not long-distance seasonal commuters at all. Rather, they spend their lives in much more localized areas, the researchers found. The discovery radically changes scientists' understanding of mantas' habits and carries dramatic implications for their conservation.

Now you see them, now you don't

With a "wingspan" that can extend more than 23 feet (7 meters), mantas are the largest rays and one of the ocean's biggest fishes. But tracking even very large animals in the open ocean can be extremely difficult, and mantas have always been especially so, according to lead study author Josh Stewart, a graduate student at the Scripps Institution of Oceanography in San Diego.

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