04.02.13 GUAM Mantas

Have you ever had the privilege of swimming with a manta ray?

They are some of the most beautiful, majestic creatures I have ever encountered (in my humble opinion). Manta rays (Manta birostris or Manta alfredi) are filter feeders from the eagle ray family Mobulidae. They are usually found in the open ocean, though Manta alfredi can be commonly found along the coast. Since Guam is pretty much all coast, you have a pretty good chance of seeing one during certain times of the year. This time of year (late February to early May) is actually a really good time to see them on Guam around dawn or dusk. Just the possibility of seeing ONE is enough of an impetus to get me up in the morning! Living on Guam,I’ve had the opportunity to see these creatures up close on several occasions over the past couple years.

On Guam, not much is known about our resident population of manta rays, so Julie Hartup, a graduate student at the University of Guam Marine Lab, has started studying them, finding out where they commonly aggregate, and what they like to feed on. She just recently published an article in the journal Coral Reefs describing feeding habits, which had previously been undocumented, of Manta alfredi on Guam (article available here: http://link.springer.com/article/10.1007/s00338-013-1022-4/fulltext.html). Julie is not only making great strides in research, but is also actively engaged with manta conservation. She is the project leader in the Marianas for a group called Manta Trust (http://www.mantatrust.org/), an organization devoted to the conservation of manta rays and their habitat through science and research while also providing education to the public and community stakeholders.Through their actions, as well as the actions of many other scientists, educators and conservationists, both species of mantas were recently approved for protection under Appendix II of CITES. This means there is now regulation to the trade of these species, which is a vital step towards their conservation.

I could go on and on about manta rays, but I think showing you some pictures from my recent encounters just may be enough to make you want to know more.

Roxanne Myers-Miller is a marine biologist at Guam Coastal Management Program.