By Tom Harrah
[dropcap]C[/dropcap]ownose rays are a species of eagle ray commonly found in the Gulf of Mexico. Found in waters up to 72 feet deep, this species can grow up to 48 inches wide from wing tip to wing tip and are thought to live 13 to 18 years. Cownose rays feed on oysters, clams, snails and crabs. These graceful creatures glide through the water by flapping their wings like a bird flying through the sky. On a recent collection trip, the staff at the Gulf Specimen Marine Lab was lucky enough to witness one of the mass migrations these cownose rays take part in. On our way in from a dive, we came upon a huge school of rays. Thousands of these rays were swimming together. Spaced out uniformly every few feet were rays as far as we could see, swimming in unison. We stopped the boat, shut off the engines and everyone on board fell silent for a moment as we watched. It was a beautiful fall day, the temperature around 75 degrees, the sky picturesque, and the surface of the water like glass. The rays passed by the boat in what seemed like an endless procession, each with a wing span of around three feet. It was a humbling sight that gives a person respect for Mother Nature and the ocean. Seeing one of these migrations is an experience you will remember forever. Cownose rays are social creatures known to migrate in schools of up to 10,000. The rays migrate northward in the late spring and southward in the late fall. Scientists believe that changes in temperature, coupled with the sun’s orientation, may trigger the seasonal migrations. Another suggestion is that the southward migration may be influenced by solar orientation while the northward migration may be influenced by water temperatures cooling below 22 deg. Celsius. The cownose ray population is currently listed as near threatened. Some scientists believe that the population is growing, but because they reproduce slowly, it is hard for their population to recover from threats. If you would like to see a video of the mass migration we observed, please visit our Facebook page and look for the post.
Tom Harrah
Gulf Specimen
Marine Lab and Aquarium
Biologist/Diver/Collector/Marine
Life Educational Programs/Sales
P.O. Box 237/222 Clark Drive/
Panacea, FL 32346
(937) 478-4514
www.gulfspecimen.org