Kemp's ridley sea turtle | |
---|---|
Lepidochelys kempii | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Reptilia |
Order: | Testudines |
Suborder: | Cryptodira |
Superfamily: | Chelonioidea |
Family: | Cheloniidae |
Genus: | Lepidochelys |
Species: | L. kempii |
Binomial name | |
Lepidochelys kempii (Garman, 1880) | |
Synonyms | |
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. 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] Kemp's ridley sea turtle is listed as endangered under the Endangered Species Act (ESA), and conservation efforts are attempting to rebuild population numbers. [7] Human activity, including but not limited to habitat destruction, climate change, and oil spills, threaten populations. [8] [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, [9] 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". [10]
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". [11] [12]
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 (79–99 lb). [13] Typical of sea turtles, it has a dorsoventrally depressed body with specially adapted flipper-like front limbs and a beak. Kemp's ridley turtle adults reach a maximum of 75 cm (30 in) in carapace length and weighing a maximum of 50 kg (110 lb). [13] The adult's oval carapace is almost as wide as it is long and is usually olive-gray in color. The carapace has five pairs of costal scutes. In each bridge adjoining the plastron to the carapace are four inframarginal scutes, each of which is perforated by a pore. The head has two pairs of prefrontal scales.
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. [14]
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. [15] 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. [16]
They are the only sea turtles that nest during the day. [17]
The distribution of L. kempii is somewhat unusual compared to most reptiles, varying significantly among adults and juveniles, as well as males and females. Adults primarily live in the Gulf of Mexico, where they forage in the relatively shallow waters of the continental shelf (up to 409 m deep, but typically 50 m or less), [5] with females ranging from the southern coast of the Florida Peninsula to the northern coast of the Yucatán Peninsula, while males have a tendency to remain closer to the nesting beaches in the Western Gulf waters of Texas (USA), Tamaulipas, and Veracruz (Mexico). [18] Adults of L. kempii are rarely found outside of the Gulf of Mexico and only 2-4% [21] : 101 p. from the Atlantic are adults. [18] [21] [19] [20]
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. [21] : 101 p. Several reports from the African coast from Morocco to Cameroon involve unverified specimens and may include misidentified L. olivacea. [18] [21] [19] [20]
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. [22]
Kemp's ridley turtle feeds on mollusks, crustaceans (such as floating crabs and shrimp), jellyfish, fish, algae or seaweed, and sea urchins. [23] [24] Juveniles primarily are pelagic surface-feeders, while adults are opportunistic bottom-feeders that feed primarily on crabs. [25] Research has shown that dives made by these turtles, including those made to forage, may be longer at night. [26] 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 there is variability in feeding habits due to habitat differences and maturation of the turtles. [25] Variation in habitat region as well as prey availability were found to alter diet composition. [27] Regional diet compositions aid in conservation efforts through enabling predicting food sources becoming affected by major events. [27]
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". [28] [29] Males will typically stay closer to breeding grounds. [30]
Juvenile turtles tend to live in floating sargassum seaweed beds for their first years. [17] Then, they range between northwest Atlantic waters and the Gulf of Mexico while growing into maturity.
They reach sexual maturity at the age of 10–12. [14]
This is the only species that nests primarily during the day. [31] 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. They mate offshore. Gravid females land in groups on beaches in arribadas [17] 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. [32] Females nest one to four times during a season, keeping 10 to 20 days between nestings. [33] Incubation takes 6–8 weeks. [33] Around 100 eggs are in a clutch. [33] 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. [33]
Kemp's ridley sea turtle is currently listed as endangered under the Endangered Species Act (ESA). [7] Egg harvesting and poaching first depleted the numbers of Kemp's ridley sea turtles, [21] 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. [7]
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. [34] And in the United States, Kemp's ridley turtle was first listed under the Endangered Species Conservation Act of 1970 [35] 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. [34] 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. [36] This revision includes an updated threat assessment. [37]
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. [38] Nesting as of 2016 is estimated to be 9.9% of the nest estimate of 1947. [38]
One mechanism used to protect turtles from fishing nets is the turtle excluder device (TED). [39] 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. [39] These mechanisms designs are controlled through federal regulations to ensure proper use. [39] There are multiple types of TED construction: oval grid, hooped, fixed angle, Super Shooter, Anthony Weedless, and flounder types. [39] Each design is adapted to be best suited for certain conditions/uses or vary by complexity of the design. [39]
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. [40] ). Wildlife officials released 10,594 Kemp's ridley hatchlings along the Texas coast in 2007. [41] The turtles are popular in Mexico as raw material for boots and as food. [41]
In July 2020, five rehabilitated turtles were released back in to Cape Cod with satellite tracking devices to monitor their wellbeing. [42] 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. [43] 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]
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. [44] [ 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. [8]
Of the endangered marine species frequenting Gulf waters, only Kemp's ridley relies on the region as its sole breeding ground. [45]
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. [46]
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. [46] Eventually, 278 nests were collected, including only a few Kemp's ridley nests. [47]
Padre Island National Seashore (PINS) is a national seashore administered by the National Park Service, located on Padre Island off the coast of South Texas, USA. In contrast to South Padre Island, known for its beaches and vacationing college students, PINS is located on the north end of Padre Island and consists of a long beach where nature is preserved.
Sea turtles, sometimes called marine turtles, are reptiles of the order Testudines and of the suborder Cryptodira. The seven existing species of sea turtles are the flatback, green, hawksbill, leatherback, loggerhead, Kemp's ridley, and olive ridley. Six of the seven sea turtle species, all but the flatback, are present in U.S. waters, and are listed as endangered and/or threatened under the Endangered Species Act. All but the flatback turtle are listed as threatened with extinction globally on the IUCN Red List of Threatened Species. The flatback turtle is found only in the waters of Australia, Papua New Guinea, and Indonesia.
Cheloniidae is a family of typically large marine turtles that are characterised by their common traits such as, having a flat streamlined wide and rounded shell and almost paddle-like flippers for their forelimbs. They are the only sea turtles to have stronger front limbs than back limbs. The six species that make up this family are: the green sea turtle, loggerhead sea turtle, olive ridley sea turtle, hawksbill sea turtle, flatback sea turtle and the Kemp's ridley sea turtle.
The leatherback sea turtle, sometimes called the lute turtle, leathery turtle or simply the luth, is the largest of all living turtles and the heaviest non-crocodilian reptile, reaching lengths of up to 2.7 metres and weights of 500 kilograms (1,100 lb). It is the only living species in the genus Dermochelys and family Dermochelyidae. It can easily be differentiated from other modern sea turtles by its lack of a bony shell; instead, its carapace is covered by oily flesh and flexible, leather-like skin, for which it is named. Leatherback turtles have a global range, although there are multiple distinct subpopulations. The species as a whole is considered vulnerable, and some of its subpopulations are critically endangered.
Bycatch, in the fishing industry, is a fish or other marine species that is caught unintentionally while fishing for specific species or sizes of wildlife. Bycatch is either the wrong species, the wrong sex, or is undersized or juveniles of the target species. The term "bycatch" is also sometimes used for untargeted catch in other forms of animal harvesting or collecting. Non-marine species that are caught but regarded as generally "undesirable" are referred to as rough fish or coarse fish.
The olive ridley sea turtle, also known commonly as the Pacific ridley sea turtle, is a species of turtle in the family Cheloniidae. The species is the second-smallest 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.
The National Marine Fisheries Service (NMFS), informally known as NOAA Fisheries, is a United States federal agency within the U.S. Department of Commerce's National Oceanic and Atmospheric Administration (NOAA) that is responsible for the stewardship of U.S. national marine resources. It conserves and manages fisheries to promote sustainability and prevent lost economic potential associated with overfishing, declining species, and degraded habitats.
A turtle excluder device (TED) is a specialized device that allows a captured sea turtle to escape when caught in a fisherman's net.
The loggerhead sea turtle is a species of oceanic turtle distributed throughout the world. It is a marine reptile, belonging to the family Cheloniidae. The average loggerhead measures around 90 cm (35 in) in carapace length when fully grown. The adult loggerhead sea turtle weighs approximately 135 kg (298 lb), with the largest specimens weighing in at more than 450 kg (1,000 lb). The skin ranges from yellow to brown in color, and the shell is typically reddish brown. No external differences in sex are seen until the turtle becomes an adult, the most obvious difference being the adult males have thicker tails and shorter plastrons than the females.
The green sea turtle, also known as the green turtle, black (sea) turtle or Pacific green turtle, is a large species of sea turtles of the family Cheloniidae. It is the only species in the genus Chelonia. Its range extends throughout tropical and subtropical seas around the world, with two distinct populations in the Atlantic and Pacific Oceans, but it is also found in the Indian Ocean. The common name refers to the usually green fat found beneath its carapace, due to its diet strictly being seagrass, not to the color of its carapace, which is olive to black.
The Australian flatback sea turtle is a species of sea turtle in the family Cheloniidae. The species is endemic to the sandy beaches and shallow coastal waters of the Australian continental shelf. This turtle gets its common name from the fact that its shell has a flattened or lower dome than the other sea turtles. It can be olive green to grey with a cream underside. It averages from 76 to 96 cm in carapace length and can weigh from 70 to 90 kg. The hatchlings, when emerging from nests, are larger than other sea turtle hatchlings when they hatch.
Ridley sea turtles are a genus (Lepidochelys) of sea turtle comprising two species: Kemp's ridley sea turtle and the olive ridley sea turtle.
The National Fish and Wildlife Foundation (NFWF) is an American foundation that was chartered by the United States Congress in 1984 to increase the resources available for the conservation of the nation's fish, wildlife, plants, and habitats.
The Sea Turtle Restoration Project (STRP), founded in 1989, is a project of Turtle Island Restoration Network (TIRN), a United States 501(c)(3) nonprofit environmental organization with a goal of protecting endangered sea turtles from human-caused threats at nesting beaches and in the ocean.
The hawksbill sea turtle is a critically endangered sea turtle belonging to the family Cheloniidae. It is the only extant species in the genus Eretmochelys. The species has a global distribution that is largely limited to tropical and subtropical marine and estuary ecosystems.
Threats to sea turtles are numerous and have caused many sea turtle species to be endangered. Of the seven extant species of sea turtles, six in the family Cheloniidae and one in the family Dermochelyidae, all are listed on the IUCN Red List of Endangered Species. The list classifies six species of sea turtle as "threatened", two of them as "critically endangered", one as "endangered" and three as "vulnerable". The flatback sea turtle is classified as "data deficient" which means that there is insufficient information available for a proper assessment of conservation status. Although sea turtles usually lay around one hundred eggs at a time, on average only one of the eggs from the nest will survive to adulthood. While many of the things that endanger these hatchlings are natural, such as predators including sharks, raccoons, foxes, and seagulls, many new threats to the sea turtle species are anthropogenic.
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Sea Turtle, Inc. is a nonprofit sea turtle rescue and rehabilitation center in South Padre Island, Texas. It is a popular regional ecotourism center, seeing about a quarter million visitors per year. Its mission is to rescue, rehabilitate, and release sick and injured sea turtles; to educate the public about sea turtles and marine conservation; and to help conserve all sea turtle species, particularly those native to the Gulf of Mexico.