Sea Turtles of the Atlantic and Gulf Coasts of the United States

Kemp’s Ridley

Kemp’s Ridley Lepidochelys kempii Cheloniidae Status National: Endangered. International: Critically Endangered. Kemp’s ridley is the most endangered of all the sea turtle species. A few thousand adult females nest in a single locality in Tamaulipas, Mexico, and a very few nest in other scattered locations, such as Padre Island, Texas. Juveniles are frequently encountered along the Gulf and East coasts, but observations of adults outside the Gulf of Mexico are relatively rare. Old films and interviews with witnesses indicate that in 1947 up to forty thousand females nested on the 60-km-long beach at Tamaulipas in a single day. By 1968, the largest single nesting group during a season had declined to an estimated five thousand individuals, and by 1978–1991, no more than two hundred females emerged to nest at one time. Since then the numbers have risen, but they do not approach the numbers seen in the late 1940s. The precipitous decline is attributed to many factors, including harvesting of eggs for human consumption, use of turtles for meat and leather, and death in nets. Conservation efforts have held off extinction, but the number of carcasses washing ashore continues to climb. Distribution and Habitats Distribution is restricted to the Gulf of Mexico and the North Atlantic Ocean. Adults apparently occur mostly in the Gulf of Mexico, but juveniles are found seasonally from Massachusetts southward along the U.S. coast. Some juveniles may be caught up in the Gulf Stream and end up near European shores. Kemp’s ridleys may travel around the ocean gyre as loggerheads do, but they return to Mexico to nest. 70 kemp’s ridley Hatchlings swim near the surface and presumably find refuge in floating debris that collects in drift lines and convergence zones, but juveniles may spend less time in the open ocean than young of the larger sea turtle species do. They return to coastal areas at a carapace length of 20–25 centimeters (8–10 inches). Ridleys spend also less time at the surface than other sea turtles, apparently darting up for a breath of air and then rapidly submerging . Juveniles tracked in the Gulf of Mexico stayed close to shore for relatively long periods. They apparently spend considerable time in shallow estuaries and tidal creeks, as some have been captured in waters behind barrier islands. The migration pattern of juveniles is not clear. Individuals may migrate north along the East Coast every summer until they mature, or that migration may be elective. Occasionally, animals are surprised by the onset of cold weather in the northern latitudes; although they may bury themselves in the mud, they may succumb to freezing temperatures. major nesting general distribution Kemp’s Ridley (Lepidochelys kempii) kemp’s ridley 71 Appearance Size Kemp’s ridleys mature at a smaller size than other sea turtles and reach an average carapace length of about 65 centimeters (25.6 inches). They may weigh up to 45 kilograms (100 pounds) as adults. Juveniles ranging from 22.8 to 60 centimeters (9–24 inches), with coloration essentially the same as adults, have been reported in Georgia waters, and one adult-sized individual was reported from South Carolina. Size at maturity varies, however, and some immature turtles may be within the adult size range. The relatively small size of adults may be correlated with a shorter time to sexual maturity compared with other sea turtles—about 10 years. Color The carapace and plastron of hatchlings are dark, but the plastron becomes lighter with age. The carapace of the juvenile and adult is greenish gray, and the skin of limbs, neck, and tail is the same color on the upper surfaces. The lower surfaces are much lighter, usually creamy white. There is no hint of reddish brown color that might cause confusion with loggerheads. Shell The general shape is more rounded than that of other sea turtles, especially in large juveniles and adults. The shell is generally about as wide as it is long if measured along the curvature of the carapace. Hatchlings have three prominent keels on the vertebral and costal scutes of the carapace that disappear with age. The keels on the costal scutes disappear at carapace lengths over 25 centimeters, while reduced vertebral (central) keels persist through the 40-centimeter size range. The nuchal scute abuts the first vertebral scute and the first left and right costal scutes. Anomalous carapace scute arrangements are rather common in...