Animals

Published on May 11th, 2012 | by James Ayre

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New Study on Manta Rays Reveals Their Hidden Lives

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May 11th, 2012 by

 
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The first study on manta rays to use satellite telemetry has just been released. The study tracks the long journeys of the giant, up-to-25-feet-wide manta ray.

The manta ray, which is currently listed as ‘Vulnerable’ by the International Union for Conservation of Nature(IUCN), is increasingly threatened by fishing and accidental capture.

“Almost nothing is known about the movements and ecological needs of the manta ray, one of the ocean’s largest and least-known species,” said Dr. Rachel Graham, lead author on the study and director of WCS’s Gulf and Caribbean Sharks and Rays Program. “Our real-time data illuminate the previously unseen world of this mythic fish and will help to shape management and conservation strategies for this species.”

The research was done by attaching satellite trackers to manta rays off the coast of the Yucatan Peninsula. Specifically, onto six individuals, of which four are adult females, one is an adult male, and one is juvenile.

“The satellite tag data revealed that some of the rays traveled more than 1,100 kilometers during the study period,” said Dr. Matthew Witt of the University of Exeter’s Environment and Sustainability Institute. “The rays spent most of their time traversing coastal areas plentiful in zooplankton and fish eggs from spawning events.”

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Manta rays are filter feeders, like whale sharks, and baleen whales. Eating by swimming through clouds of plankton and fish eggs with their mouths open, and filtering them from the water.

The research found that while they spent almost all their time in the coastal waters, they were only in marine-protected areas 11.5 percent of the time. The majority of their time was spent in areas used as major shipping routes, leaving them open to ship strikes.

“Studies such as this one are critical in developing effective management of manta rays, which appear to be declining worldwide,” said Dr. Howard Rosenbaum, Director of WCS’s Ocean Giant Program.

Regardless of how they look, they are harmless to humans. They also possess the highest brain-to-body ratio of all sharks and rays. And they give birth to live young, at a slow pace, one or two to a litter, every two years or so.

Their numbers have been decreasing around the world, largely because of being caught for shark bait and demand for their filters, used in traditional Chinese medicine.

Source: Wildlife Conservation Society
Image Credits: Manta Rays and Manta Ray Madive via Shutterstock

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About the Author

's background is predominantly in geopolitics and history, but he has an obsessive interest in pretty much everything. After an early life spent in the Imperial Free City of Dortmund, James followed the river Ruhr to Cofbuokheim, where he attended the University of Astnide. And where he also briefly considered entering the coal mining business. He currently writes for a living, on a broad variety of subjects, ranging from science, to politics, to military history, to renewable energy. You can follow his work on Google+.



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  • http://doubleblue.com Tim of the Deep

    The hidden life should have been unknown facets of a pelagic manta ray’s life. I think it is just a poor choice of words. But this is huge news. We know virtually nothing and have no regulations regarding international fisheries management. These pelagic mantas, which are different from coastal mantas in Hawaii, Yap and parts of Indonesia, etc. travel huge distances through many international borders. Even if they are protected in one country or state, they may not be protected in the next. This applies to many creatures including dolphins, whales, schooling fish, great white and probably other sharks, whale sharks and many others we have yet to study, like molamolas. The fact that they are incredibly vulnerable to predation through 88.5% of their lives means we must ACT NOW or see pelagic mantas and other vanish in the next decade. The article states that they are used in “traditional Chinese medicine”, but this tradition is new and economically driven. Manta gill rakers weren’t used 10 years ago. This is an important finding and you should be concerned because the next generation won’t have mantas around. They’ll all be fished out for greed.

  • Suzanne

    Have had the fortune of swimming with and photographing many mantas in hawaii
    When they have been feeding in Hanauma bay

    If you would like some photos for ID I can send you some aloha suzanne. Nice article

    • http://zacharyshahan.com Zachary Shahan

      That would be wonderful. :D You can send to zach@planetsave.com

  • chisel

    wow….. i think the article’s ambition is hidden :(

  • Kevin

    Jessica….really???

  • http://None Jessica

    So is there any animal on the planet not being exploited to death by the freaking Chinese? Including their own unwanted children!

  • Maggie

    So, that’s the big finding about their “hidden life”? 11.5%? Blah. The title of this article is misleading.

  • emil

    Wheres the hidden life?

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