In our previous chapters we covered Eagle, Southern, and Caribbean Rays because they are the most commonly encountered by our readers. However, those three barely scratch the surface since there are over 500 known species of rays and skates and scientists continue to identify new species around the world in both salt and fresh water.
The most magnificent species is the Manta Ray, a pelagic plankton eater, and fortunate indeed are the few who see one in the wild. Sadly, the largest documented Manta was by-catch caught off the coast of China three years ago by local fishermen in a small fishing boat. That Manta fought to its death and was towed behind the boat because it was too large to bring aboard. It weighed approximately 3,300lb; its wingspan was over 16 feet and it was wider than the stern of the boat. It sold for less than 50 cents per pound and was rendered into fish oil, leather, and the small fraction that was edible went to elite diners.
Like many other marine creatures, little is known about the rays. How long do they live? How far do they travel? How old are they when they reach maturity? When do they begin reproducing and for how long? What is the survival rate of the young? How many are lost to by-catch, habitat destruction, and pollution? But, most importantly, a question often asked of plant and animal species that are losing ground every day in the fight for life â€¦ could rays hold the key to mans’ survival?
Historically, ethnic peoples around the world took rays for meat as well as to use their barbs as harpoons, weapons, ritualistic bloodletting tools and, between the Maya and Taino, as trade goods. Rays were a source of food for those living along coasts; however, today, ray meat is making its way to expensive restaurants where, like Blue-Fin tuna, it sells for exorbitant prices. Because a ray’s skin is covered in denticles (small, rough tooth-like protrusions), it was also used as sandpaper, especially by traditional wood carvers.
A ray’s skin is quite tough and is often made into leather known as shagreen. Shagreen is the leather of choice for high end book bindings, handbags, travel cases, and furniture. It is also in great demand for sword and knife scabbards as well as the grips of those weapons because shagreen’s natural roughness prevents slippage.
Also increasing in popularity is the skin of the Cowtail Ray. When smoothed and polished it becomes galuchat. Galuchat is highly prized for its pearl like appearance and is used as decoration on expensive writing instruments, wallets, watch bands, and ornamental boxes. The pearlized leather has led many, particularly in Asia, to call this species the Pearled Ray. Many fear that Cowtail Rays are rapidly approaching extinction due to their prized skin â€¦ another species falling into the abyss for the sake of human ego.
Returning to the question of what secrets rays may hold that will benefit mankind. Just this spring, Mote Marine and researchers at University of South Florida, Daemen College, and Clemson University announced they were recipients of a $1.3 million grant from the U. S. Department of Defense.
The purpose of the grant is to study the rays’ miraculous ability to heal wounds without complication of infection including horrific damage caused by shark attacks and boat strikes.Â Although the Defense Department’s hopes lie in finding a treatment for battlefield wounds, the results of this research could benefit people around the world.
The research will be dual-focused with studies on microbes that cause human wound infections including MRSA, the virulent anti-biotic resistant staph infection that kills thousands of hospital patients each year in the states alone. The second area of study will be directed at identifying what it is that prevents infection in the wounds of rays and skates. It has been known for some time that the skin of some amphibians and fish contains an infection preventive agent; however, rays and skates are only now gaining the recognition that they, too, possess some kind of infection control agent.
In reference to the ray’s ability to heal, Dr. Carl Luer, Manager of Mote’s Marine biomedical Research Program said: “People have observed remarkable healing abilities in these fishes for decades, but to our knowledge there have been no controlled scientific studies of how this process works.Â We plan to look at the basic processes of wound healing and look for new chemical compounds that prevent infection.”
Imagine the benefit this research could produce â€¦ saving lives on the battlefield, in hospitals, nursing homes, and in our very own homes. Are we willing to trade this potential lifesaving benefit for a $500 watch band or a $350 pen?
Becky Bauer became a scuba instructor and award-winning journalist covering the marine environment in the Caribbean after 30 years as a wild and domestic animal rescuer, rehabber, and educator in the States. She is a contributing photographer to NOAA