Kemp's Ridley Turtle (Lepidochelys kempii)

	Kemp's Ridley Turtle (Lepidochelys kempii) Photo: NOAA

	Did You Know? · The species is named after Richard M. Kemp, a fisherman from Key West, FL, who first submitted the species for identification in 1906. · The Kemp's ridley is only one of two species of sea turtles that nest in arribadas (the other is the olive ridley). · Kemp's ridleys are the only sea turtle species that nests predominantly during daylight hours.

Status
ESA Endangered - throughout its range

Taxonomy
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Order: Testudines
Family: Cheloniidae
Genus: Lepidochelys
Species: kempii

Species Description
Adult Kemp's ridleys, considered the smallest marine turtle in the world, weigh on average around 100 pounds (45 kg) with a carapace (top shell) measuring between 24-28 inches (60-70 cm) in length. The almost circular carapace has a grayish green color while the plastron (bottom shell) is pale yellowish to cream in color. The carapace is often as wide as it is long and contains 5 pairs of costal "scutes". Each of the front flippers has one claw while the back flippers may have one or two.

Similar to olive ridleys, Kemp's ridleys display one of the most unique synchronized nesting habits in the natural world. Large groups of Kemp's ridleys gather off a particular nesting beach near Rancho Nuevo, Mexico, in the state of Tamaulipas. Then wave upon wave of females come ashore and nest in what is known as an "arribada," 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. Scientists have yet to conclusively determine the cues for ridley arribadas. Arribada nesting is a behavior found only in the genus Lepidochelys.

Female Kemp's ridleys nest from May to July, laying two to three clutches of approximately 100 eggs, which incubate for 50-60 days. After incubation, hatchlings emerge weighing about half an ounce (14 g) and measuring about 1.5 inches (3.8 cm).

Kemp's Ridley Turtle
(Lepidochelys kempii)
Photo: National Park Service

Habitat
Adult Kemp's primarily occupy "neritic" habitats. Neritic zones typically contain muddy or sandy bottoms where prey can be found. Their diet consists mainly of swimming crabs, but may also include fish, jellyfish, and an array of mollusks.

Depending on their breeding strategy, male Kemp's ridleys appear to 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 opportunistically encountered.

Female Kemp's have been tracked migrating to and from nesting beaches in Mexico. Females leave breeding and nesting areas and continue on to foraging zones ranging from the Yucatán Peninsula to southern Florida. Some females take up residence in specific foraging grounds for months at a time, leading scientists to suggest that females have a goal-oriented migration, opposed to the suggested wandering strategy employed by olive ridleys. Kemp's ridleys rarely venture into waters deeper than 160 ft (50 m) (Byles and Plotkin, 1994).

Newly emerged hatchlings inhabit a much different environment than adult turtles. After emerging from the nest, hatchlings enter the water and must swim quickly to escape near shore predators. There is strong evidence that many sea turtle species employ an open ocean developmental stage because encounters with healthy, neonate sea turtles are extremely rare in near shore waters. 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.

Juveniles of many species of sea turtles have been known to associate with floating sargassum seaweed, utilizing the sargassum as an area of refuge, rest, and/or food. This developmental drifting period is hypothesized to last about two years or until the turtle reaches a carapace length of about 8 inches (20 cm). Subsequently, these sub-adult turtles return to neritic zones of the Gulf of Mexico or northwestern Atlantic Ocean to feed and develop until they reach adulthood (Collard and Ogren, 1990).

Kemp's Ridley Turtle
(Lepidochelys kempii)
Photo: Kim Bassos-Hull,
Mote Marine Laboratory

Distribution
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.

There is only one confirmed Kemp's ridley arribada in the state of Tamaulipas, Mexico, where nearly 95% of worldwide Kemp's ridley nesting occurs. The three main nesting beaches in Tamaulipas, Mexico are Rancho Nuevo, Tepehuajes, and Barra del Tordo. Nesting also occurs in Veracruz, Mexico, and Texas, U.S., but on a much smaller scale. Occasional nesting has been documented in North Carolina, South Carolina, and the Gulf and Atlantic coasts of Florida.

Population Trends
The Kemp's ridley has experienced a historical, dramatic decrease in arribada size. An amateur video from 1947 documented an extraordinary Kemp's ridley arribada near Rancho Nuevo. It has been estimated that approximately 42,000 Kemp's ridleys nested during that single day! 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 (Hildebrand, 1963).

This video has also served to measure the species' collapse. Twenty years after the video was filmed, the largest arribada measured was just 5,000 individuals. Between the years of 1978 and 1991 only 200 Kemp's ridleys nested annually. Today the Kemp's ridley population appears to be in the early stages of recovery. Nesting has increased steadily over the past decade. During the 2000 nesting season, an estimated 2,000 females nested at Rancho Nuevo, a single arribada of 1,000 turtles was reported in 2001, and an estimated 3,600 turtles produced over 8,000 nests in 2003. In 2006, a record number of nests were recorded since monitoring began in 1978; 12,143 nests were documented in Mexico, with 7,866 of those at Rancho Nuevo.

On the Texas coast, 251 Kemp's ridley nests were recorded from 2002-2006. For the 2007 nesting season, 127 nests have been recorded in Texas, with 73 of those nests documented at Padre Island National Seashore. Those 127 nests are a record for the Texas coast, passing the 2006 record of 102 nests.

Threats
Kemp's ridleys face threats on both 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. Egg collection was an extreme threat to the population, but since nesting beaches were afforded official protection in 1966, this threat no longer poses a major concern.

For more information, please visit our threats to marine turtles page.

Conservation Efforts
Kemp's ridley turtles are protected by various international treaties and agreements. They are listed in Appendix I of the Convention on International Trade in Endangered Species of Wild Flora and Fauna (CITES), which means that international trade of this species is prohibited. Kemp's ridleys are listed in Appendices I and II of the Convention on Migratory Species (CMS ). Kemp's ridleys are also protected under Annex II of the Specially Protected Areas and Wildlife (SPAW ) Protocol of the Cartagena Convention. Additionally, the U.S. is a party to the Inter-American Convention for the Protection and Conservation of Sea Turtles (IAC ), which is the only binding international treaty dedicated exclusively to marine turtles.

In the U.S., NOAA's National Marine Fisheries Service (NMFS) and the U.S. Fish and Wildlife Service (USFWS) have joint jurisdiction for marine turtles, with NMFS having the lead in the marine environment and USFWS having the lead on the nesting beaches. Both federal agencies, and a number of state agencies, have promulgated regulations to eliminate or reduce threats to sea turtles. In the Atlantic and Gulf of Mexico, NMFS has required measures (e.g., gear modifications, changes to fishing practices, and time/area closures) to reduce sea turtle bycatch in mid-Atlantic gillnet, Chesapeake Bay pound net, and southeast shrimp and flounder trawl fisheries.

NMFS has worked closely with the shrimp trawl fishing industry to develop turtle excluder devices (TEDs) to reduce the mortality of sea turtles incidentally captured in shrimp trawl gear. TEDs that are large enough to exclude even the largest sea turtles are now required in shrimp trawl nets. Since 1989, the U.S. has embargoed shrimp harvested in a manner that adversely affects sea turtles. The import ban does not apply to nations that have adopted sea turtle protection programs comparable to that of the U.S. (e.g., require and enforce the use of TEDs) or to nations where incidental capture in shrimp fisheries does not present a threat to sea turtles (e.g., nations that fish for shrimp in areas where sea turtles do not occur). The U.S. Department of State (DOS) is the principal implementing agency of this law, while NMFS serves as technical advisor. NMFS has provided extensive TED training throughout the world.

In 2003, NMFS developed the Strategy for Sea Turtle Conservation and Recovery in Relation to Atlantic and Gulf of Mexico Fisheries (Strategy) to evaluate and address domestic sea turtle bycatch comprehensively across jurisdictional (i.e., state and Federal) and fishing sector (i.e., commercial and recreational) boundaries on a per-gear basis in fisheries of the Atlantic and Gulf of Mexico.

NMFS is currently involved in cooperative gear research projects designed to reduce sea turtle bycatch in the Atlantic sea scallop dredge fishery, the Chesapeake Bay pound net fishery, and non-shrimp trawl fisheries in the Atlantic and Gulf.

In 1991, NMFS and USFWS finalized the recovery plan for Kemp's ridleys in the U.S. Caribbean, Atlantic, and Gulf of Mexico. Since that time, a wealth of new information has been gained regarding Kemp's biology, distribution, and population status as well as threats to the species. Therefore, NMFS and USFWS have initiated a revision of the Kemp's ridley recovery plan for the U.S. Caribbean, Atlantic, and Gulf of Mexico. For more information on this process, please visit the joint USFWS/NMFS website on the Kemp's ridley recovery plan revision.

The Mexican government has played a vital role in the conservation of the Kemp's ridley. The Kemp's ridley has benefited from legal protection by Mexico since the 1960s. In 1977, a refuge was established at the only known nesting beach and included the Rancho Nuevo nesting beach as part of a system of reserves for sea turtles. On May 28, 1990, a complete ban on taking any species of sea turtle was implemented by the Mexican government. In 2002, the beach at Rancho Nuevo was designated as a Natural Protected Area under the category of Sanctuary; and in February 2004, it was included on the list of RAMSAR sites.

Regulatory Overview
The Kemp's ridley turtle was first listed under the Endangered Species Conservation Act of 1970 on December 2, 1970, and subsequently under the Endangered Species Act (ESA) of 1973.

NMFS implements measures to reduce sea turtle interactions in fisheries by regulations and permits under the ESA and Magnuson-Stevens Fishery Conservation and Management Act. In 1992, NMFS finalized regulations to require TEDs in shrimp trawl fisheries to reduce interactions between turtles and trawl gear. Since then, NMFS has modified these regulations as new information became available on increasing the efficiency of TEDs (e.g., larger TEDs are now required to exclude larger turtles). Since the early 1990s, NMFS has implemented sea turtle conservation measures including, but not limited to, TEDs in trawl fisheries, large circle hooks in longline fisheries, time and area closures for gillnets, and modifications to pound net leaders. Click here for a list of NMFS regulations to protect marine turtles.

Key Documents
(All documents are in PDF format.)

Title	Federal Register	Date
5-Year Review	n/a	08/31/2007
Virginia Pound Net Fishery Regulations	71 FR 36024	06/23/2006
Status Review of Sea Turtles Listed Under the Endangered Species Act of 1973	61 FR 17	01/02/1996
TED Regulations for Shrimp Trawls	57 FR 57348	12/04/1992
Recovery Plan - U.S. Caribbean, Atlantic, and Gulf of Mexico	56 FR 38424	08/13/1991
ESA Listing Rule	35 FR 18319	12/02/1970

More Information

Literature Cited

Byles, R.A., and Plotkin, P.T. 1994. Comparison of the migratory behavior of the congeneric sea turtles Lepidochelys olivacea and L. kempii. In Schroeder, B.A., and Witherington, B.E. (compilers). Proceedings of the Thirteenth Annual Symposium on Sea Turtle Biology and Conservation. NOAA Technical Memorandum NMFS-SEFSC-341, p. 39.
Collard, S.B., and Ogren, L.H. 1990. Dispersal scenarios for pelagic post-hatchling sea turtles. Bulletin of Marine Science 47:233-243.
Hildebrand, H.H. 1963. Hallazgo del área de anidación de la tortuga lora Lepidochelys kempii (Garman), en la costa occidental de Golfo de Mexico (Rept., Chel.). Ciencia, México 22: 105-112.