The Manta Ray In February, 2009, I had the pleasure of meeting one of the largest and most beautiful creatures on the planet and in the sea, the pelagic Manta Ray. Her name is Nandi, and she is located at the Georgia Aquarium in Atlanta, Georgia. Nandi was rescued from shark nets off the coast of South Africa, and was rehabilitated. I had always loved rays, big and small, but the Manta Ray sparked my interest even further. Manta Rays, or Manta birostris, are one of the largest but least-known elasmobranches, which are a subclass of cartilaginous fishes encompassing sharks and rays. They are also called Atlantic Manta, Australian Devilray, Devilfish, Pacific Manta, and many others. Like other members of the shark and ray family, their skeleton is made entirely of cartilage. They are also of close relation to the Stingray, but do not have a stinger. They can be recognized by their large triangular pectoral fins and projecting cephalic fins, forward extensions of the pectoral fins that project on either side of the head, as shown below: [pic]

Adult Mantas can reach a maximum width of 22 feet, and weigh up to 3,000 pounds. The colorization of the Manta is unique to each animal, ranging from dark brown, grayish blue, or black on top and white underneath. Manta Rays are very rarely kept in captivity due to their size. Only five aquariums in the world have Mantas on display, including the Georgia Aquarium, which is the home of my new friend Nandi. The Georgia Aquarium just added a new Manta Ray in September of this year. The habitat of the Manta Ray includes the warm tropic waters throughout the Atlantic Ocean, including the regions of South Carolina, Brazil, and Bermuda. They are also known to be as far north as New Jersey and extending all the way down to San Diego, California. It normally stays close to the shore, near coral and rocky reefs, and swims at the surface of the water. Manta rays frequent cleaning stations on coral reefs where small fish such as wrasse, and angelfish swim in the Manta's gills and over its skin to feed, in the process cleaning it of parasites and dead tissue. [pic] When a male Manta is ready to mate with a female, the Florida Museum of Natural History states that the male ray bites the pectoral fins of the females before aligning themselves, abdomen to abdomen, inserting one clasper, or posterior extension, into the female’s cloaca, which is the posterior opening that serves as the only opening for the reproductive tract. Mantas are occasionally observed leaping completely out of the water, sometimes one after the other. The purpose of this behavior is not well understood, and may be related to mating displays or giving birth. The female Manta Rays reproduce by a method called ovoviviparity, in which each of the mother’s pups are wrapped in a thin shell of mucous membrane inside the mother, and are later born alive. Gestation time is believed to be about 13 months. One pup is born per breeding season. At the time of birth, the pup can be up to 25 pounds and 4 feet long. Although they are often solitary creatures, Mantas can be found in large groups in an area rich with food. They are giant filter feeders, feeding on various organisms called plankton, and also feeding on small fish. Their filtering mechanism consists of plates of pinkish-brown sponge-like tissue located between the gill bars that support the gills. When feeding, the cephalic lobs unfurl, and the plankton-rich water is directed towards the mouth. Nine to twelve rows of tiny grinding teeth exist in the bottom jaw. These teeth barely penetrate the skin. There are no teeth in the upper jaw. A full grown adult Manta can consume up to 60 pounds of food a day. The Manta’s feeding habits are related to its habitat and its migratory habits, as it tends to migrate towards waters that offer large concentrations of food, including the coral reefs it tends to be so fond of. The only predators in the water of the Manta, since they are so large in size, are sharks and whales. The largest predator of the Manta Ray, unfortunately, is humans. The Manta Ray was once commercially harvested off Australia and California waters for its liver oil and for its abrasive skin. Today, thankfully, it is rarely hunted, although its meat is considered a delicacy in the Philippines, Mexico, and Indonesia. However, according to The Hawaiian Association for Marine Research and Education, a new market has emerged in Asia, creating a demand for dried manta gill plates to be used in traditional medicines and in the treatment of cancer. This demand has led to an increase in the Indonesian fishery in just a few years. This fishery is a great threat to the Manta Ray populations. Also, as a result of over fishing, fishermen have turned to hunting manta rays as an alternative source of income. This has led to a increase in manta ray harvesting. An estimated 1,500 manta rays have been taken over a period of six months in Lamakera, Indonesia. There is an increased fear that this harvesting could spread to the Western Pacific. Although the Manta Ray is not considered endangered, there have been many conservation efforts to preserve their being. The Manta Pacific Research Foundation is currently working to determine the critical Manta Ray habitat in order to create new conservation products. Since Mantas are of minimal danger to humans, dive tourism and interaction with the creatures has become a popular activity. The Mantas sometimes approach divers, seemingly interested and curious. Where divers may touch the Mantas, they could develop skin lesions from the removal of the mucous membrane that coats their skin. Ironically, even though we are the biggest predator of the Manta Rays, the creature is very curious about us and is not afraid of human interaction.

Bibliography “About Nandi”. Georgia Aquarium. http://www.georgiaaquarium.org/nandi/about-nandi/. Retrieved 10-22-2009 “Manta Rays”. The Hawaii Association for Marine Education and Research, Inc.. http://www.hamerinhawaii.org/Main%20Web%20Pages/Education/Marine%20Life/Rays/manta_rays.htm. Retrieved 10-23-2009. “Manta Biological Profile”. Florida Museum of Natural History. http://www.flmnh.ufl.edu/fish/gallery/Descript/MantaRay/MantaRay.html. Retrieved 10-22-2009 “Manta Ray Facts”. Manta Ray World. http://www.mantaray-

world.com/index.html. Retrieved 10-21-2009

Manta Pacific Research Foundation. http://www.mantapacific.org/mantapacific/.

Retrieved 10-23-2009