The Kemp's Ridley Sea Turtle
Only 8,000 Kemp's ridley turtles are estimated to swim the world's oceans today, making it the rarest of all sea turtle species. The Kemp's ridley is a small turtle with a circular to heart-shaped keeled carapace. They are carnivorous and feed on swimming crabs and other crustaceans, clams, mussels, fish and jellyfish.
This rare animal makes its home around the Gulf of Mexico foraging in coastal and estuarine waters, particularly along the Louisiana coast and the Campeche, Mexico region. Juvenile and subadult Kemp's ridleys are widely distributed throughout the coastal waters of the U.S. from Texas to Maine. When temperatures begin to drop, the turtles in the northern regions head south to Florida and the Gulf of Mexico.
The location of Kemp's ridley nesting beaches remained a mystery for many years. Fishermen maintained that there were no nesting beaches because the Kemp's ridley was an infertile hybrid between a loggerhead and hawksbill turtle. The mystery was solved with the discovery of a film made in 1947 by a Mexican engineer.
The film documented the mass emergence of approximately 42,000 Kemp's ridley turtles in broad daylight onto a remote beach on the Gulf coast of Mexico. The beach was near Rancho Nuevo in the state of Tamaulipas about 200 miles south of Brownsville, Texas. The video also provided evidence of Kemp's ridley egg collection. Dozens of villagers are seen on the beach excavating the nests and subsequent interviews have suggested that 80% of the nests, about 33,000, were collected and transported to local villages.
The nesting that occurs on this one 20 mile stretch of Mexican coastline represents virtually the entire reproductive effort of the species. The reproductive strategy of the Kemp's ridley is to synchronize the emergence of nesting females. These mass nestings, called arribadas (Spanish for arrivals), occur at irregular intervals between April and June.
Why ridleys nest together in large grounds is unknown but it may serve as a form of predator saturation or swamping. Local predators may be bewildered by the sudden abundance of prey and, although some adults and many eggs, and later, hatchlings will be taken, many will survive. Predators seem to know when an arribdada is about to occur because coyotes and vultures move from inland areas to gather at the beach before the turtles arrive.
Kemp's ridleys face threats on nesting beaches and in the marine environment. The greatest cause of decline and the continuing primary threat to Kemp's ridleys is incidental capture in fishing gear, primarily in shrimp trawls, but also in gill nets, longlines, traps and pots, and dredges in the Gulf of Mexico and North Atlantic.
Loggerhead Marinelife Center
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