About The Species
Found primarily in the Gulf of Mexico, but also in the Atlantic Ocean as far north as Nova Scotia, Kemp’s ridley turtles are the smallest marine 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.
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, it may help to reduce predation. The other species of sea turtle that nests en mass is the olive ridley.
Status
Prior to the mid-20th century, the Kemp's ridley was abundant in the Gulf of Mexico. Historic information indicates that tens of thousands of ridleys nested near Rancho Nuevo, Mexico, during the late 1940s. An amateur video from 1947 documented an extraordinary Kemp's ridley nesting event near Rancho Nuevo. It has been estimated that approximately 42,000 Kemp's ridleys nested during that single day.
The Rancho Nuevo population experienced a devastating decline between the late 1940s and the mid-1980s. The number of nests was at 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 nests remained below previous highs until 2017 when total documented nests reached near 25,000. At this time, it is unclear if future nesting will steadily and continuously increase, similar to what occurred from 1990-2009, or if nesting will continue to exhibit ups and downs as recorded in the past 5 years.
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
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 and contains five pairs of costal "scutes” that overlay the bony carapace. Each of the front flippers has one claw while the back flippers may have one or two.
Behavior and Diet
Sea turtles spend most of their lives in the ocean, but females leave the water to lay eggs. Air breathers, they must come to the surface regularly to breathe. Kemp’s ridleys are the only sea turtles that routinely nests during the day.
Kemp’s ridley turtles spend their first years of life primarily in deep oceanic waters of the Gulf of Mexico, where they feed on small animals and plants they find in the mats of floating algae. After recruiting to shallow coastal areas, crabs are their preferred food; however, they have been documented to also scavenge on dead fish and discarded bycatch.
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 primarily occupy nearshore coastal (neritic) habitats which typically contain muddy or sandy bottoms where their preferred prey are found.
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 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. Some females take up residence in specific foraging grounds for months at a time and return to the same foraging grounds in subsequent years.
Ninety-five percent of worldwide Kemp’s ridley nesting occurs in 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, and Florida.
Newly emerged hatchlings inhabit a much different environment than adult turtles. After emerging from the nest, hatchlings enter the water and swim rapidly offshore. Some sea turtle species remploy an open ocean developmental stage because healthy, neonate sea turtles are rarely found 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.
Juvenile Kemp’s ridleys associate with floating Sargassum algae, using the Sargassum as an area of refuge, rest, and a place to feed. This developmental drifting period is hypothesized to last about 1-2 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 where they mature.
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, estimates of lifespan are on the order of 30 years minimally. Scientists have estimated that Kemp’s ridleys reach sexual maturity at about 13 years of age.
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 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 as well as Kemp’s ridley.
Females nest from May to July during daylight hours. They lay an average of two to three 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.
Threats
Bycatch in Fishing Gear
The primary ongoing threat to Kemp's ridley sea turtles is bycatch in fishing gear. Kemp’s ridleys are primarily caught in shrimp trawls, but also in recreational fishing gear, gill nets, traps and pots, and dredges in the Gulf of Mexico and northwest Atlantic.
Harvest of Eggs
Almost the entire Kemp’s ridley sea turtle population nests along the coast of the state of Tamaulipas, on the Gulf coast of Mexico, just south of the United States-Mexico border. Historically, egg collection was an extreme threat in this area, but since nesting beaches were afforded protection in both Mexico and the United States, this threat no longer poses a major concern.
Ocean Pollution/Marine Debris
Marine turtles may die after ingesting fishing line, balloons, or plastic bags, plastic pieces, or other plastic debris which they can mistake for food. They may also become entangled in marine debris, including discarded or lost fishing gear, and can be killed or seriously injured.
Scientific Classification
| Animalia |
Chordata |
Reptilia |
Testudines |
Cheloniidae |
Lepidochelys |
kempii |
