THE OLIVE RIDLEY SEA TURTLE

 

The olive ridley sea turtle (Lepidochelys olivacea), also known commonly as the Pacific ridley sea turtle, is a species of turtle in the family Cheloniidae. The species is the second-smallest^[4][5] and most abundant of all sea turtles found in the world. L. olivacea is found in warm and tropical waters, primarily in the Pacific and Indian Oceans, but also in the warm waters of the Atlantic Ocean.^[4]

This turtle and the related Kemp's ridley sea turtle are best known for their unique synchronised mass nestings called arribadas, where thousands of females come together on the same beach to lay eggs.^[4][5]

The olive ridley sea turtle may have been first described as Testudo mydas minor by Georg Adolf Suckow in 1798. It was later described and named Chelonia multiscutata by Heinrich Kuhl in 1820. Still later, it was described and named Chelonia olivacea by Johann Friedrich von Eschscholtz in 1829. The species was placed in the subgenus Lepidochelys by Leopold Fitzinger in 1843.^[6] After Lepidochelys was elevated to full genus status, the species was called Lepidochelys olivacea by Charles Frédéric Girard in 1858. Because Eschscholtz was the first to propose the specific epithet olivacea, he is credited as the binomial authority or taxon author in the valid name Lepidochelys olivacea (Eschscholtz, 1829). The parentheses indicate that the species was originally described in a different genus.

 

 

The generic name, Lepidochelys, is derived from the Greek words lepidos, meaning scale, and chelys, which translates to turtle. This could possibly be a reference to the supernumerary costal scutes characteristic of this genus.^[7] The etymology of the English vernacular name "olive" is somewhat easier to resolve, as its carapace is olive green in color.^[8] However, the origin of "ridley" is unknown, perhaps derived from "riddle".^[9][10] Lepidochelys is the only genus of sea turtles containing more than one extant species: L. olivacea and the closely related L. kempii (Kemp's ridley).^[10]

Growing to about 61 cm (2 ft) in carapace length (measured along the curve), the olive ridley sea turtle gets its common name from its olive-colored carapace, which is heart-shaped and rounded. Males and females grow to the same size, but females have a slightly more rounded carapace as compared to males.^[4] The heart-shaped carapace is characterized by four pairs of pore-bearing inframarginal scutes on the bridge, two pairs of prefrontals, and up to nine lateral scutes per side. L. olivacea is unique in that it can have variable and asymmetrical lateral scute counts, ranging from five to nine plates on each side, with six to eight being most commonly observed.^[7] Each side of the carapace has 12–14 marginal scutes.

 

 

The carapace is flattened dorsally and highest anterior to the bridge. It has a medium-sized, broad head that appears triangular from above. The head's concave sides are most obvious on the upper part of the short snout. It has paddle-like fore limbs, each having two anterior claws. The upper parts are grayish-green to olive in color, but sometimes appear reddish due to algae growing on the carapace. The bridge and hingeless plastron of an adult vary from greenish white in younger individuals to a creamy yellow in older specimens (maximum age is up to 50 years).^[7][11]

Hatchlings are dark gray with a pale yolk scar, but appear all black when wet.^[7] Carapace length of hatchlings ranges from 37 to 50 mm (1.5 to 2.0 in). A thin, white line borders the carapace, as well as the trailing edge of the fore and hind flippers.^[11] Both hatchlings and juveniles have serrated posterior marginal scutes, which become smooth with age. Juveniles also have three dorsal keels; the central longitudinal keel gives younger turtles a serrated profile, which remains until sexual maturity is reached.^[7]

 

The olive ridley sea turtle rarely weighs over 50 kg (110 lb). Adults studied in Oaxaca, Mexico,^[7] ranged from 25 to 46 kg (55 to 101 lb); adult females weighed an average of 35.45 kg (78.2 lb) (n=58), while adult males weighed significantly less, averaging 33.00 kg (72.75 lb) (n=17). Hatchlings usually weigh between 12.0 and 23.3 g (0.42 and 0.82 oz).

Adults are sexually dimorphic. The mature male has a longer and thicker tail, which is used for copulation,^[7] and the presence of enlarged and hooked claws on the male's front flippers allows him to grasp the female's carapace during copulation. The male also has a longer, more tapered carapace than the female, which has a rounded, dome-like carapace.^[7] The male also has a more concave plastron, believed to be another adaptation for mating. The plastron of the male may also be softer than that of the female.^[11]

The olive ridley turtle has a circumtropical distribution, living in tropical and warm waters of the Pacific and Indian Oceans from India, Arabia, Japan, and Micronesia south to southern Africa, Australia, and New Zealand. In the Atlantic Ocean, it has been observed off the western coast of Africa and the coasts of northern Brazil,

 

 The population of Pacific Mexico was estimated to be at least 10 million prior to the era of mass exploitation. More recently, the global population of annual nesting females has been reduced to about two million by 2004,^[16] and was further reduced to 852,550 by 2008.^[1][17] This indicated a dramatic decrease of 28–32% in the global population within only one generation (i.e., 20 years).^[14]

 

 

Olive ridley sea turtles are considered the most abundant, yet globally they have declined by more than 30% from historic levels.^{[citation needed]} These turtles are considered endangered because of their few remaining nesting sites in the world. The eastern Pacific turtles have been found to range from Baja California, Mexico, to Chile. Pacific olive ridleys nest around Costa Rica, Mexico, Nicaragua, and the northern Indian Ocean; the breeding colony in Mexico was listed as endangered in the US on July 28, 1978.^[18]

 

Olive ridley hatchling

 

 Nesting

 

 

 

Olive ridley turtles exhibit two different nesting behaviours: solitary nesting (the most prevalent) and synchronized mass nesting, termed arribadas.^[11] They are unique among sea turtle species in the latter behaviour, for which they are best known. Females return to the same beach from where they hatched, to lay their eggs. They lay their eggs in conical nests about 1.5 ft (0.46 m) deep, which they laboriously dig with their hind flippers.^[4] In the Indian Ocean, Arabian Sea near Honavar in Karnataka , the majority of Olive Ridleys nest in two or three large assemblies near Gahirmatha in Odisha. The coast of Odisha in India is one of the largest mass nesting sites for the Olive Ridley, along with the coasts of Mexico and Costa Rica.^[4] In 1991, over 600,000 turtles nested along the coast of Odisha in one week. Solitary nesting also occurs in Lothian Island Wildlife Sanctuary in West Bengal and along the Coromandel Coast and Sri Lanka, but in scattered locations. However, olive ridleys are considered a rarity in most areas of the Indian Ocean.^[17] Some nesting populations exist in islands of Bangladesh near Cox's Bazar.^[19]

 

 

They are also rare in the western and central Pacific, with known arribadas occurring only within the tropical eastern Pacific, in Central America and Mexico. In Costa Rica, they occur at Nancite and Ostional beach, and a third arribada beach seems to be emerging at Corozalito. Two active arribada beaches are located in Nicaragua, Chacocente and La Flor, with a smaller arribada beach of unknown status on the Pacific coast of Panama. Historically, arribadas happened at several beaches in Mexico, but in the present arribadas are only observed at Playa Escobilla and Morro Ayuda in Oaxaca, and Ixtapilla in Michoacan.^[17]

 

 

Although olive ridleys are famed for their arribadas, most of the known nesting beaches are only frequented by solitarily nesting females and support a relatively small quantity of nests (100 to 3,000 nests). The overall contribution and importance of solitary nesting females to the population may be underestimated by the scientific community as the hatching success rate of nests at arribada beaches is generally low, but high at solitary nesting beaches.^[7]

Isolated, irregular nesting events also sporadically occur within the species' range.^[20]

Some of the olive ridley's foraging grounds near Southern California are contaminated due to sewage, agricultural runoff, pesticides, solvents, and industrial discharges. These contaminants have been shown to decrease the productivity of the benthic community, which negatively affects these turtles, which feed from these communities.^[7] The increasing demand to build marinas and docks near Baja California and Southern California are also negatively affecting the olive ridleys in these areas, where more oil and gasoline will be released into these sensitive habitats. Another threat to these turtles is power plants, which have documented juvenile and subadult turtles becoming entrained and entrapped within the saltwater cooling intake systems.^[7]

 

An olive ridley sea turtle laying eggs

Mating is often assumed to occur in the vicinity of nesting beaches, but copulating pairs have been reported over 1,000 km from the nearest beach. Research from Costa Rica revealed the number of copulating pairs observed near the beach could not be responsible for the fertilization of the tens of thousands of gravid females, so a significant amount of mating is believed to have occurred elsewhere at other times of the year.^[7]

 

 

The Gahirmatha Beach in Kendrapara district of Odisha (India), which is now a part of the Bhitarkanika Wildlife Sanctuary, is the largest breeding ground for these turtles. The Gahirmatha Marine Wildlife Sanctuary, which bounds the Bhitarkanika Wildlife Sanctuary to the east, was created in September 1997, and encompasses Gahirmatha Beach and an adjacent portion of the Bay of Bengal. Bhitarkanika mangroves were designated a Ramsar Wetland of International Importance in 2002. It is the world's largest known rookery of olive ridley sea turtles. Apart from Gahirmatha rookery, two other mass nesting beaches have been located, which are on the mouth of rivers Rushikulya and Devi. The spectacular site of mass congregation of olive ridley sea turtles for mating and nesting enthralls both the scientists and the nature lovers throughout the world.

 

 Olive ridley sea turtles migrate in huge numbers from the beginning of November, every year, for mating and nesting along the coast of Orissa. Gahirmatha coast has the annual nesting figure between 100,000 and 500,000 each year. A decline in the population of these turtles has occurred in the recent past due to mass mortality. The olive ridley sea turtle has been listed on Schedule – I of the Indian Wildlife (Protection) Act, 1972 (amended 1991). The species is listed as vulnerable under IUCN.^[1] The sea turtles are protected under the 'Migratory Species Convention' and Convention of International Trade on Wildlife Flora and Fauna (CITES). India is a signatory nation to all these conventions. The homing characteristics of the ridley sea turtles make them more prone to mass casualty. The voyage to the natal nesting beaches is the dooming factor for them. Since Gahirmatha coast serves as the natal nesting beach for millions of turtles, it has immense importance on turtle conservation.

 

 Olive ridleys generally begin to aggregate near nesting beaches about two months before nesting season, although this may vary throughout their range. In the eastern Pacific, nesting occurs throughout the year, with peak nesting events (arribadas) occurring between September and December. Nesting beaches can be characterized as relatively flat, midbeach zone, and free of debris.^[6] Beach fidelity is common, but not absolute. Nesting events are usually nocturnal, but diurnal nesting has been reported, especially during large arribadas.^[7] Exact age of sexual maturity is unknown, but this can be somewhat inferred from data on minimum breeding size. For example, the average carapace length of nesting females (n = 251) at Playa Nancite, Costa Rica, was determined to be 63.3 cm (24.9 in), with the smallest recorded at 54.0 cm (21.3 in).^[7] Females can lay up to three clutches per season, but most only lay one or two clutches.^[11] The female remains near shore for the internesting period, which is about one month. Mean clutch size varies throughout its range and decreases with each nesting attempt.^[17]

 

A mean clutch size of 116 (30–168 eggs) was observed in Suriname, while nesting females from the eastern Pacific were found to have an average of 105 (74–126 eggs).^[11] The incubation period is usually between 45 and 51 days under natural conditions, but may extend to 70 days in poor weather conditions. Eggs incubated at temperatures of 31 to 32 °C (88 to 90 °F) produce only females; eggs incubated at 28 °C (82 °F) or less produce solely males; and incubation temperatures of 29 to 30 °C (84 to 86 °F) produce a mixed-sex clutch.^[11] Hatching success can vary by beach and year, due to changing environmental conditions and rates of nest predation.

Most observations are typically within 15 km (9.3 mi) of mainland shores in protected, relatively shallow marine waters (22–55 m deep).^[11] Olive ridleys are occasionally found in open waters. The multiple habitats and geographical localities used by this species vary throughout its lifecycle.^[6]

The olive ridley is predominantly carnivorous. Common prey items include tunicates (salps and sea squirts), starfish, sea urchins, bryozoans, squid, bivalves, snails, barnacles, shrimp, crabs, rock lobsters, and sipunculid worms.^[21][22] Additionally, consumption of jellyfish and both adult fish (e.g. Sphoeroides) and fish eggs may be indicative of pelagic (open ocean) feeding.^[11] The olive ridley is also known to feed on filamentous algae in areas devoid of other food sources. Captive studies have indicated some level of cannibalistic behavior in this species.^[7]

Threats

Olive ridley entangled in a ghost net within the Maldives

Known predators of olive ridley eggs include raccoons, coyotes, feral dogs and pigs, opossums, coatimundi, caimans (Caiman, Paleosuchus), ghost crabs, and the sunbeam snake.^[11] Hatchlings are preyed upon as they travel across the beach to the water by vultures (Cathartes, Coragyps atratus), frigate birds, crabs (Gecarcinus, Ocypode), raccoons, coyotes, iguanas, and snakes. In the water, hatchling predators most likely include oceanic fishes, sharks, and crocodiles. Adults have relatively few known predators, other than tiger sharks and crocodiles, and killer whales are responsible for occasional attacks.^[23] On land, nesting females may be attacked by jaguars. Notably, the jaguar is the only cat with a strong enough bite to penetrate a sea turtle's shell, thought to be an evolutionary adaption from the Holocene extinction event.^{[citation needed]} In observations of jaguar attacks, the cats consumed the neck muscles of the turtle and occasionally the flippers, but left the remainder of the turtle carcass for scavengers as most likely, despite the strength of its jaws, a jaguar still cannot easily penetrate an adult turtle's shell to reach the internal organs or other muscles. In recent years, increased predation on turtles by jaguars has been noted, perhaps due to habitat loss and fewer alternative food sources. Sea turtles are comparatively defenseless in this situation, as they cannot pull their heads into their shells like freshwater and terrestrial turtles.^[7][24] Females are often plagued by mosquitos during nesting. Humans are still listed as the leading threat to L. olivacea, responsible for unsustainable egg collection, slaughtering nesting females on the beach, and direct harvesting adults at sea for commercial sale of both the meat and hides.^[11]

 

 

Other major threats include mortality associated with boat collisions, and incidental takes in fisheries. Trawling, gill nets, ghost nests, longline fishing, and pot fishing have significantly affected olive ridley populations, as well as other species of marine turtles.^[1][7] Between 1993 and 2003, more than 100,000 olive ridley turtles were reported dead in Odisha, India from fishery-related practices.^[25] In addition, entanglement and ingestion of marine debris is listed as a major threat for this species. Coastal development, natural disasters, climate change, and other sources of beach erosion have also been cited as potential threats to nesting grounds.^[7] Additionally, coastal development also threatens newly hatched turtles through the effects of light pollution.^[26] Hatchlings which use light cues to orient themselves to the sea are now misled into moving towards land, and die from dehydration or exhaustion, or are killed on roads.

 

 

The greatest single cause of olive ridley egg loss, though, results from arribadas, in which the density of nesting females is so high, previously laid nests are inadvertently dug up and destroyed by other nesting females.^[7] In some cases, nests become cross-contaminated by bacteria or pathogens of rotting nests. For example, in Playa Nancite, Costa Rica, only 0.2% of the 11.5 million eggs produced in a single arribada successfully hatched. Although some of this loss resulted from predation and high tides, the majority was attributed to conspecifics unintentionally destroying existing nests. The extent to which arribadas contribute to the population status of olive ridleys has created debate among scientists. Many believe the massive reproductive output of these nesting events is critical to maintaining populations, while others maintain the traditional arribada beaches fall far short of their reproductive potential and are most likely not sustaining population levels.^[7] In some areas, this debate eventually led to legalizing egg collection.

Historically, the olive ridley has been exploited for food, bait, oil, leather, and fertilizer. The meat is not considered a delicacy; the egg, however, is esteemed everywhere. Egg collection is illegal in most of the countries where olive ridleys nest, but these laws are rarely enforced. Harvesting eggs has the potential to contribute to local economies, so the unique practice of allowing a sustainable (legal) egg harvest has been attempted in several localities.^[17] Numerous case studies have been conducted in regions of arribadas beaches to investigate and understand the socioeconomic, cultural, and political issues of egg collection. Of these, the legal egg harvest at Ostional, Costa Rica, has been viewed by many as both biologically sustainable and economically viable. Since egg collection became legal in 1987, local villagers have been able to harvest and sell around three million eggs annually. They are permitted to collect eggs during the first 36 hours of the nesting period, as many of these eggs would be destroyed by later nesting females. Over 27 million eggs are left unharvested, and villagers have played a large role in protecting these nests from predators, thereby increasing hatching success.^[7]

 

 

Most participating households reported egg harvesting as their most important activity, and profits earned were superior to other forms of available employment, other than tourism. The price of Ostional eggs was intentionally kept low to discourage illegal collection of eggs from other beaches. The Ostional project retained more local profits than similar egg-collection projects in Nicaragua,^[17] but evaluating egg-harvesting projects such as this suffers from the short timeline and site specificity of findings. In most regions, illegal poaching of eggs is considered a major threat to olive ridley populations, thus the practice of allowing legal egg harvests continues to attract criticism from conservationists and sea turtle biologists. Plotkin's Biology and Conservation of Ridley Sea Turtles, particularly the chapter by Lisa Campbell titled "Understanding Human Use of Olive Ridleys", provides further research on the Ostional harvest (as well as other harvesting projects). Scott Drucker's documentary, Between the Harvest, offers a glimpse into this world and the debate surrounding it.

The endangered Olive Ridley turtles released into the sea near Visakhapatnam

 

 

The olive ridley is classified as vulnerable according to the International Union for Conservation of Nature and Natural Resources, and is listed in Appendix I of CITES. These listings were largely responsible for halting the large-scale commercial exploitation and trade of olive ridley skins.^[1] The Convention on Migratory Species and the Inter-American Convention for the Protection and Conservation of Sea Turtles have also provided olive ridleys with protection, leading to increased conservation and management for this marine turtle. National listings for this species range from endangered to threatened, yet enforcing these sanctions on a global scale has been unsuccessful for the most part. Conservation successes for the olive ridley have relied on well-coordinated national programs in combination with local communities and nongovernment organizations, which focused primarily on public outreach and education. Arribada management has also played a critical role in conserving olive ridleys.^[17] Lastly, enforcing the use of turtle excluder devices in the shrimp-trawling industry has also proved effective in some areas.^[1] Globally, the olive ridley continues to receive less conservation attention than its close relative, Kemp's ridley (L. kempii). Also, many schools arrange trips for students to carry out the conservation project, especially in India.

 

 

Another major project in India involved in preserving the olive ridley sea turtle population was carried out in Chennai, where the Chennai wildlife team collected close to 10,000 eggs along the Marina coast, of which 8,834 hatchlings were successfully released into the sea in a phased manner.^[27]

 

In March 2023, in Honnavar, India, local fishers sighted 86 sea turtle nests, with over 5,000 eggs in them, along a 3-km stretch of beach between Apsarakonda and Pavinkorava. The highest number of nests previously recorded in the area, 34, was in 2008.^[28]

 

 

 

 

 

 

 

 

 

 

 L. olivacea distribution map: Red circles are major nesting grounds; yellow circles are minor nesting beaches.

 

 

 

 

 

 

 

 

 

 

 

 

THE KEMP'S RIDLEY SEA TURTLE

 

Kemp's ridley sea turtle^[4] (Lepidochelys kempii), also called commonly the Atlantic ridley sea turtle, Kemp's ridley turtle, and Kemp's ridley, is a species of turtle in the family Cheloniidae. L. kempii is the rarest species of sea turtle and is the world's most endangered species of sea turtle as well as the smallest. It is one of two living species in the genus Lepidochelys (the other one being L. olivacea, the olive ridley sea turtle). The species L. kempii primarily occupies habitat around the Gulf of Mexico, though its migrations into the Atlantic Ocean are being affected by rising temperatures.^[5][6] Rising sea temperatures expand this species range, leaving them vulnerable to cold-shocking events when weather changes.^[7] Kemp's ridley sea turtle is listed as endangered under the Endangered Species Act (ESA), and conservation efforts are attempting to rebuild population numbers.^[8] Human activity, including habitat destruction, climate change, and oil spills, threaten populations.^[9][6]

This species of turtle is called Kemp's ridley because Richard Moore Kemp (1825–1908) of Key West was the first to send a specimen to Samuel Garman at Harvard,^[10] but the origin of the name "ridley" itself is unknown. Prior to the term being popularly used (for both species in the genus), L. kempii at least was known as the "bastard turtle".^[11]

 

 

At least one source also refers to Kemp's ridley as a "heartbreak turtle". In her book The Great Ridley Rescue, Pamela Philips claimed the name was coined by fishermen who witnessed the turtles dying after being "turned turtle" (on their backs). The fishermen said the turtles "died of a broken heart".^[12][13]

Kemp's ridley is the smallest of all sea turtle species, reaching maturity at 58–70 cm (23–28 in) carapace length and weighing only 36–45 kg (80–100 lb).

 

These turtles change color as they mature. As hatchlings, they are almost entirely a dark purple on both sides, but mature adults have a yellow-green or white plastron and a grey-green carapace.^[15]

 

 

Kemp's ridley has a triangular-shaped head with a somewhat hooked beak with large crushing surfaces. The skull is similar to that of the olive ridley.^[16] Unlike other sea turtles, the surface on the squamosal bone where the jaw opening muscles originate faces to the side rather than to the back.^[17]

They are the only sea turtles that nest during the day.^[18]

 

The distribution of

 

 

Juveniles and subadults, in contrast, regularly migrate into the Atlantic Ocean and occupy the coastal waters of the continental shelf of North America from southern Florida to Cape Cod, Massachusetts, and occasionally northward. The time periods of these migrations appear to be growing longer due to rising sea temperatures.^[6] Accidental and vagrant records are known with some regularity from throughout the northern Atlantic Ocean and Mediterranean Sea, where the Gulf Stream is believed to play a significant role in their dispersal. Confirmed records from Newfoundland to Venezuela in the west; to Ireland, the Netherlands, Malta in the Mediterranean, and numerous localities in between are known in the east, although more than 95% of these involve juveniles or subadults.^{[22]: 101 p.} Several reports from the African coast from Morocco to Cameroon involve unverified specimens and may include misidentified L. olivacea.^{[19][20][21][22]}

 

 

 

In November 2021 a male was found alive on Talacre beach in North Wales. The turtle was taken to the Anglesey Sea Zoo for treatment, with the intent of eventual transportation back to the Gulf of Mexico.^[23]

Kemp's ridley turtle feeds on mollusks, crustaceans (such as floating crabs and shrimp), jellyfish, fish, algae or seaweed, and sea urchins.^[24][25] Juveniles primarily are pelagic surface-feeders, while adults are opportunistic bottom-feeders that feed primarily on crabs.^[26] Research has shown that dives made by these turtles, including those made to forage, may be longer at night.^[27] Comparing dietary habits of head-started turtles (turtles raised in captivity before release) and wild turtles found little difference in variance in feeding habits, but variability exists in feeding habits due to habitat differences and maturation of the turtles.^[26] Variation in habitat region, as well as prey availability, were found to alter diet composition.^[28] Regional diet compositions aid in conservation efforts through enabling predicting food sources becoming affected by major events.^[28]

Most females return each year to a single beach—Rancho Nuevo in the Mexican state of Tamaulipas—to lay eggs. The females arrive in large groups of hundreds or thousands in nesting aggregations called arribadas, which is a Spanish word for "arrivals".^[29][30] Males will typically stay closer to breeding grounds.^[31]

Juvenile turtles tend to live in floating sargassum seaweed beds for their first years.^[18] Then, they range between northwest Atlantic waters and the Gulf of Mexico while growing into maturity.

This is the only species that nests primarily during the day.^[32] The nesting season for these turtles is April to August. They nest mostly (95%) on a 16-mile beach in the Mexican state of Tamaulipas and on Padre Island in the US state of Texas, and elsewhere on the Gulf Coast.^[33] They mate offshore. Gravid females land in groups on beaches in arribadas^[18] or mass nesting. They prefer areas with dunes, or secondarily, swamps. The estimated number of nesting females in 1947 was 89,000, but shrank to an estimated 7,702 by 1985.^[34] Females nest one to four times during a season, keeping 10 to 20 days between nestings.^[35] Incubation takes 6–8 weeks.^[35] Around 100 eggs are in a clutch.^[35] The hatchlings' sex is decided by the temperature in the area during incubation. If the temperature is below 29.5 °C, the offspring will be mainly male.^[35]

Kemp's ridley sea turtle is currently listed as endangered under the Endangered Species Act (ESA).^[8] Egg harvesting and poaching first depleted the numbers of Kemp's ridley sea turtles,^[22] but today, major threats include habitat loss, pollution, and entanglement in shrimping nets. Some major current conservation efforts are aimed towards habitat protection, reduction of bycatch, rescue and rehabilitation, and reduction of killing.^[8]

 

 

Efforts to protect L. kempii began in 1966, when Mexico's Instituto Nacional de Investigaciones Biologico-Pesqueras (National Institute of Biological-Fisheries Research) sent biologists Hunberto Chávez, Martin Contreras, and Eduardo Hernondez to the coast of southern Tamaulipas, to survey and instigate conservation plans.^[36] And in the United States, Kemp's ridley turtle was first listed under the 

 

 

Endangered Species Conservation Act of 1970^[37] on December 2, 1970, and subsequently under the Endangered Species Act of 1973. In 1977 an informal, binational multiagency, the Kemp's Ridley Working Group, first met to develop a recovery plan.^[36] A binational recovery plan was developed in 1984, and revised in 1992. A draft public review draft of the second revision was published by National Marine Fisheries Service in March 2010.^[38] This revision includes an updated threat assessment.^[39]

From 1947 to 1985, L. kempii nests experienced a sharp decline from an estimated 121,517 nests in 1947 to 702 nests in 1985 (decline of 99.4%), and have since been exponentially recovering until approximately 2011–2016, where another decline in nests occurred.^[40] Nesting as of 2016 is estimated to be 9.9% of the nest estimate of 1947.^[40]

 

 

One mechanism used to protect turtles from fishing nets is the turtle excluder device (TED).^[41] It is a grid of bars with an opening at the top or bottom, fitted into the neck of the shrimp trawl. It works by allowing small animals to slip through bars and get caught, while sea turtles strike the bars and are ejected through an escape hole on either the top or bottom of the device.^[41] These mechanisms designs are controlled through federal regulations to ensure proper use.^[41] There are multiple types of TED construction: oval grid, hooped, fixed angle, Super Shooter, Anthony Weedless, and flounder types.^[41] Each design is adapted to be best suited for certain conditions/uses or vary by complexity of the design.^[41]Kemp's ridley nests found on the Texas coast 1985-2013

Kemp's ridley hatchlings. Rancho Nuevo, Tamaulipas, Mexico. 2017

In September 2007, Corpus Christi, Texas, wildlife officials found a record of 128 Kemp's ridley sea turtle nests on Texas beaches, including 81 on North Padre Island (Padre Island National Seashore) and four on Mustang Island. The figure was exceeded in each of the following 7 years (see graph to 2013, provisional figures for 2014 as at July, 118.^[42]). Wildlife officials released 10,594 Kemp's ridley hatchlings along the Texas coast in 2007.^[43] The turtles are popular in Mexico as raw material for boots and as food.^[43]

 

 In July 2020, five rehabilitated turtles were released back in to Cape Cod with satellite tracking devices to monitor their wellbeing.^[44] A 2020 rescue mission to save 30 turtles from the freezing seas of Cape Cod was delayed by weather and technical issues, spurring a temporary rescue mission en route between Massachusetts and New Mexico. The Tennessee Aquarium offered overnight shelter and care, and the turtles were eventually released to the sea.^[45] These cold-stunning events may become more common with rising sea temperatures, as juveniles linger in near-shore waters in the American Northeast and are subjected to late-season storms.^[6]

 

 

As of June 13, 2025, 383 Kemp's ridley nests were documented on the Texas coast—breaking the previous record of 353 nests set in 2017 at Padre Island National Seashore.^[46]

 

 

 A Kemp's ridley arribada in Rancho Nuevo beach, Tamaulipas, Mexico, in 2017

Some Kemp's ridleys were airlifted from Mexico after the 1979 blowout of the Ixtoc 1 rig, which spilled millions of gallons of oil into the Gulf of Mexico.^{[citation needed]}

 

 

Since April 30, 2010, 10 days after the accident on the Deepwater Horizon, 156 sea turtle deaths were recorded; most were Kemp's ridleys.^{[citation needed]} Louisiana Department of Wildlife and Fisheries biologists and enforcement agents rescued Kemp's ridleys in Grand Isle.^{[47][citation needed]} Most of the 456 oiled turtles that were rescued, cleaned, and released by the US Fish and Wildlife Service were Kemp's ridleys.^[9]

Of the endangered marine species frequenting Gulf waters, only Kemp's ridley relies on the region as its sole breeding ground.^[48]

 

 

As part of the effort to save the species from some of the effects of the Deepwater Horizon oil spill, scientists took nests and incubated them elsewhere; 67 eggs were collected from a nest along the Florida Panhandle on June 26, 2010, and brought to a temperature-controlled warehouse at NASA's Kennedy Space Center, where 56 hatched,^{[citation needed]} and 22 were released on 11 July 2010.^[49]

 

 

The overall plan was to collect eggs from about 700 sea turtle nests, incubate them, and release the young on beaches across Alabama and Florida over a period of months.^[49] Eventually, 278 nests were collected, including only a few Kemp's ridley nests.^[50]

 

 

 Since the 2010 Deepwater horizon spill, scientists have identified the δ13C values present in turtle scutes to reflect the incorporation of oil. Exposure to oil and the subsequent incorporation of δ13C isotopes has been linked to lessened reproductive success of Kemp's Ridley sea turtles.^[51]

 

 

 

 

 

 

 

 

 

 

 

 Distribution of Kemp's ridley sea turtle: red dot = primary nesting beach; green= adult male range;^[19] dark blue = adult female range;^[19] mid-blue = juvenile and subadult range; arrows = Gulf Stream; light blue = accidentals and vagrants (95% juveniles and subadults), black dots = verified records^[20][21]