A Kemp's Ridley sea turtle on the beach - Credit: Kate Sampson, NOAA Fisheries
A Kemp's Ridley sea turtle on the beach - Credit: Kate Sampson, NOAA Fisheries
About the Species
Kemp’s ridley sea turtles are the smallest sea turtle in the world. The species is named after Richard M. Kemp, a fisherman from Key West, Florida, who first submitted the species for identification in 1906. They are primarily found in the Gulf of Mexico, but juveniles are also found in the Atlantic Ocean as far north as Nova Scotia and sometimes even occur in the eastern North Atlantic.
Kemp’s ridley were once abundant in the Gulf of Mexico with tens of thousands of females nesting at Rancho Nuevo, Mexico. The population crashed in the mid-20th century to a low of only several hundred females nesting in the 1980s. Intensive conservation actions were implemented on nesting beaches and through fisheries management. Bycatch in commercial and recreational fishing gear continues to be the biggest threat facing Kemp’s ridley sea turtles.
NOAA Fisheries and our partners are dedicated to protecting and recovering the Kemp’s ridley sea turtle. We use a variety of innovative techniques to study, protect, and recover this endangered species. We engage our partners as we develop measures and recovery plans that foster the conservation and recovery of Kemp’s ridleys and their habitats. And we fund research, monitoring, and conservation projects to implement priorities outlined in recovery plans.
Population Status
The Kemp’s ridley sea turtle is listed as endangered under the Endangered Species Act. Prior to the mid-20th century, the Kemp's ridley was abundant in the Gulf of Mexico. An amateur video from 1947 documented tens of thousands of Kemp’s ridleys nesting near Rancho Nuevo, Mexico on a single day. This nesting population experienced a devastating decline between the late 1940s and the mid-1980s. The number of nests reached a record low of 702 in 1985, representing fewer than 250 nesting females. Due to intensive conservation actions, the Kemp's ridley began to slowly rebound during the 1990s. The number of nests increased about 15 percent each year through 2009. However, in 2010 this rapid increase abruptly ended and the number of nests has fluctuated since then. The unexpected change in Kemp’s ridley nesting highlights the importance of continued protection, monitoring, and conservation efforts.
The majority of Kemp’s ridley nesting occurs on the beaches of the western Gulf of Mexico and ninety-five percent of worldwide Kemp’s ridley nesting occurs in the state of Tamaulipas, Mexico. The three main nesting beaches in Tamaulipas are Rancho Nuevo, Tepehuajes, and Barra del Tordo. Nesting also occurs in Veracruz, Mexico, and in Texas, but on a much smaller scale. Occasional nesting has been documented in North Carolina, South Carolina, Georgia, Florida, and Alabama.
The 2015 5-year review of the Kemp's ridley sea turtle under the ESA provides additional information on abundance and population trends.
Protected Status
ESA Endangered
CITES Appendix I
Appearance
The Kemp's ridley turtle has a triangular-shaped head with a slightly hooked beak. Hatchlings are darkly colored on both sides. Adults are generally a grayish-green color on top with a pale, yellowish bottom shell. The top shell (carapace) is often as wide as it is long. Each of the front flippers has one claw while the back flippers may have one or two.
Behavior and Diet
Kemp’s ridley turtles, like all sea turtles, are marine reptiles and must come to the surface to breathe. Adult female sea turtles return to land to lay their eggs in the sand—they are remarkable navigators and usually return to a beach in the general area where they hatched decades earlier.
The Kemp's ridley is one of two species of sea turtles that engage in "arribada" nesting, where large groups of females gather offshore and come onto the beach to nest all at once. Nesting in large groups may be a defense against predators, or a result of environmental factors influencing nesting. With many turtles coming ashore together and many nests subsequently hatching at the same time, the large numbers of hatchlings entering the ocean may help to overwhelm predators and ensure that more hatchlings make it to open water to reduce predation. The other species of sea turtle that nests en masse is the olive ridley. They are the only sea turtles that routinely nest during the day.
After emerging from the nest, hatchlings enter the water and swim rapidly offshore. Some hatchlings remain in currents within the Gulf of Mexico while others may be swept out of the Gulf, around Florida, and into the Atlantic Ocean by the Gulf Stream. Juvenile Kemp’s ridleys associate with floating Sargassum algae, using the Sargassum as an area of refuge, rest, and a place to feed on small animals and plants. This developmental drifting period lasts 1 to 2 years or until the turtle reaches a length of about 8 inches. After this oceanic phase, Kemp’s ridleys migrate to nearshore areas of the Gulf of Mexico or northwestern Atlantic Ocean. After recruiting to shallow coastal areas, crabs are their preferred food; however, they also scavenge on discarded bycatch.
Depending on their breeding strategy, male Kemp's ridleys occupy many different areas within the Gulf of Mexico. Some males migrate annually between feeding and breeding grounds, yet others may not migrate at all, mating with females encountered at their feeding grounds or near nesting beaches. Female Kemp's ridleys have been tracked migrating to and from nesting beaches in Mexico and south Texas. Females leave breeding and nesting areas and migrate to foraging areas ranging from the Yucatán Peninsula to southern Florida to the north-central Gulf of Mexico. Some females take up residence in specific foraging grounds for months at a time and return to the same foraging grounds in subsequent years.
Where They Live
Kemp's ridleys are distributed throughout the Gulf of Mexico and U.S. Atlantic seaboard, from Florida to New England. A few records exist for Kemp's ridleys near the Azores, waters off Morocco, and within the Mediterranean Sea and they are occasionally found in other areas around the Atlantic Basin. Adult Kemp's ridleys primarily occupy nearshore coastal (neritic) habitats in the Gulf of Mexico that include muddy or sandy bottoms where their preferred prey are found.
World map providing approximate representation of the Kemp's ridley turtle's range.
Lifespan & Reproduction
No one knows exactly how long Kemp’s ridleys live, but like other sea turtles, they are likely long-lived, reaching maturity at about 13 years of age and have an estimated lifespan of at least 30 years.
Kemp's ridleys display one of the most unique synchronized nesting habits in the natural world. Adult female Kemp's ridleys gather off nesting beaches in northeastern Mexico and come ashore in large groups, called arribadas, which means "arrival" in Spanish. There are many theories on what triggers an arribada, including offshore winds, lunar cycles, and the release of pheromones by females. However, scientists have yet to conclusively determine what triggers an arribada. Arribada nesting is a behavior found only in the genus Lepidochelys which includes the olive ridley sea turtle (Lepidochelys olivacea) and Kemp’s ridley.
Nesting occurs from April to July and unlike the other species which nest at night, Kemp’s ridleys nest during daylight hours. They lay an average of 2 to 3 clutches per season, and return to the beach to nest every 1 to 3 years. The females dig an egg chamber in the sand where they lay approximately 100 eggs, which incubate for 50 to 60 days. Hatchlings orient seaward by moving away from the darkest silhouette of the landward dune or vegetation to crawl towards the brightest horizon. On undeveloped beaches, this is toward the open horizon over the ocean.
Threats
Bycatch in Fishing Gear
A primary threat to sea turtles is their unintended capture in fishing gear which can result in drowning or cause injuries that lead to death or debilitation (for example, swallowing hooks, or flipper entanglement). The term for this unintended capture is bycatch. Sea turtle bycatch is a worldwide problem. Kemp’s ridleys are primarily caught in trawls, gillnets, longlines, hook and lines, pot/traps, and dredges in the Gulf of Mexico and northwest Atlantic.
Direct Harvest of Turtles and Eggs
Almost the entire Kemp’s ridley sea turtle population nests on the beaches of the western Gulf of Mexico, primarily in Tamaulipas, Mexico, just south of the United States-Mexico border. The arribada nesting behavior concentrates females and nests at the same time and in the same place, enabling the taking of an extraordinary number of eggs for human consumption. Historically, egg collection for human consumption was a significant problem in this area, but this threat has been diminished by the protection of nests and turtles in both Mexico and the United States.
Loss and Degradation of Nesting Habitat
Coastal development and rising seas from climate change are leading to the loss of nesting beach habitat for sea turtles. Shoreline hardening or armoring (e.g., seawalls) can result in the complete loss of dry sand suitable for successful nesting. Artificial lighting on and near nesting beaches can deter nesting females from coming ashore to nest and can disorient hatchlings trying to find the sea after emerging from their nests.
For Kemp’s ridleys, beach driving is a threat to the turtles and the nesting habitat. Driving on nesting beaches can injure or kill nesting turtles, eggs, and hatchlings. Nesting turtles can be difficult to see and they cannot move quickly on land to avoid an approaching vehicle. Beach driving also degrades the nesting habitat by causing sand compaction and creating ruts and ridges in the sand that pose obstacles to nesting turtles and hatchlings attempting to reach the ocean, resulting in an extended period of travel or entrapment.
Predation of Eggs and Hatchlings
The destruction and consumption of eggs and hatchlings by non-native and native predators, such as feral pigs, coyotes, raccoons, birds, and crabs is a threat to Kemp’s ridley sea turtles. Predation control is an effective tool to reduce this threat and improve in situ hatching success.
Vessel Strikes
Vessel strikes are a threat to sea turtles near ports and waterways along developed coastlines throughout their range. Various types of watercraft can strike sea turtles when they are at or near the surface, resulting in injury or death. High boat traffic areas such as marinas and inlets present a higher risk. Adult sea turtles, in particular nesting females, are more susceptible to vessel strikes when making reproductive migrations and while they are nearshore during the nesting season.
Ocean Pollution/Marine Debris
Increasing pollution of nearshore and offshore marine habitats threatens all sea turtles and degrades their habitats. The Deepwater Horizon oil spill was the largest offshore oil spill in U.S. history and affected nesting (including nesting females, eggs, and hatchlings), small juvenile, large juvenile, and adult sea turtles throughout the Gulf of Mexico. Ingestion of marine debris is another threat to all species of sea turtles. Kemp’s ridley turtles may ingest fishing line, balloons, plastic bags, floating tar or oil, and other materials discarded by humans which they can mistake for food. They may also become entangled in marine debris, including lost or discarded fishing gear, and can be killed or seriously injured.
Climate Change
For all sea turtles, a warming climate is likely to result in changes in beach morphology and higher sand temperatures, which can be lethal to eggs or alter the ratio of male and female hatchlings produced. Rising seas and storm events cause beach erosion, which may flood nests or wash them away. Changes in the temperature of the marine environment are likely to alter the abundance and distribution of food resources, leading to a shift in the migratory and foraging range and nesting season of kemp's ridleys.
Scientific Classification
| Animalia |
Chordata |
Reptilia |
Testudines |
Cheloniidae |
Lepidochelys |
kempii |
