Loggerhead sea turtle
| Loggerhead Sea Turtle | |
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| Genus: | Caretta Rafinesque, 1814
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| Species: | C. caretta
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| Binomial name | |
| Caretta caretta Linnaeus, 1758
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The Loggerhead Sea Turtle (Caretta caretta) is a sea turtle and the only member of the genus Caretta. The genus name "Caretta" is a latinization of the French "caret", meaning turtle, tortoise, or sea turtle.[1] A loggerhead sea turtle reportedly grows up to 800 lbs (364 kg) and 3.5 feet (1.1 m) long.[2] Their shell color is a reddish brown color, and the color of their skin is brown yellow.
Ecology and life history
Trophic ecology
The species feeds on mollusks, crustaceans, fish, jellyfish, crabs, shrimp,and Portuguese Man o' War, and other small to medium-sized marine animals, which they crush with their large and powerful jaws. As with other sea turtles, females return to lay their eggs on or near the same beach where they hatched. Unlike other sea turtles, courtship and mating usually do not take place near the nesting beach but rather along the migration routes between feeding and breeding grounds.
Scientists in Hawaii use satellite transponders to track loggerhead sea turtles in the Northern Pacific Ocean.[3]
Life history
In the Mediterranean, Loggerheads mate from late March to early June. The female nesting season is at its peak in June and July, but this depends on the nesting beach. The clutch may vary from 70 to 150 eggs. Each egg is roughly the size and shape of a ping-pong ball. The average interval between nesting seasons is two to three years.
Loggerhead turtles are the most common sea turtle to nest in the United States. Loggerheads nest from Texas to Virginia to North Carolina, requiring soft sandy beaches, where there is little light; with the largest concentration of nests in south Florida. Statistics collected in Florida since 1998 however indicate the lowest nesting levels Florida has seen in 17 years, where nesting rates have declined from 85,988 nests in 1998 to approximately 45,084 in 2007.[4]
After approximately 60 days, the hatchlings emerge usually at night when protection from predation is greater. Usually following the brightest light to the ocean's edge, an artificial light, such as from a home can lead them astray. Once in the ocean they use ocean currents to travel to the Sargasso Sea using the Sargassum as protection until they mature.[5]
An alternative to migration for many loggerheads is hibernation to varying degrees as the water cools. Loggerhead turtles have no bones on the tip of their front legs. By February they are submerged for up to seven hours at a time, emerging for only seven minutes to recover. Although outdone by freshwater turtles, these are the longest recorded dives for any air-breathing marine vertebrate[6].
Most loggerheads that reach adulthood live for longer than 30 years, and can often live past 198.7 years.[7] They are immune to the toxins of a Portuguese Man o' War as the turtles have often been seen feeding on them.
Etymology and taxonomic history
Two subspecies are recognized: Caretta caretta gigas, is found in the Indian and Pacific Oceans, and C. caretta caretta, the Atlantic loggerhead, also found in south Italy and the Greek islands of Zakynthos, Kefalonia, Crete, and the Peloponese and in Dalyan in southwestern Turkey. (see article; June Haimoff).
Importance to humans
Loggerhead Sea Turtles were once intensively hunted for their meat and eggs, along with their fat which was used in cosmetics and medication. The Loggerhead Sea Turtles were also killed for their shells, which are used to make items such as combs. As a result, both subspecies are now internationally protected.
Conservation
Today the main threat to the adult loggerheads lies in shrimp trawls and crab fishing nets, to which many loggerheads annually fall victim. Furthermore, adults are often injured by speedboat propellers and by swallowing fishing hooks or getting caught in nets. Internationally, animal protection organizations take pains to monitor and protect the turtles' nesting grounds in Turkey,[8] Greece[9], Bonaire, and Costa Rica. The turtles can also be found around the Italian islands of Lampedusa and Linosa, off the coast of Sicily, and in Calabria, where it is particularly endangered. Furthermore, the turtles are known to nest on the beaches of Cyprus, especially Akamas and Alagadi Beach.[10]
In many places during the nesting season, workers search the coastline to find evidence of nests. Once found, a nest will be uncovered and the eggs carefully counted, if the nest is dangerously located the eggs will be moved to a better spot. Plastic fencing will be placed at or near the surface to protect the eggs from large predators such as raccoons or even dogs. The barrier used is large enough to allow the hatchlings to emerge without difficulty. The nests are checked daily for disturbances; several days after there is indication that the eggs have hatched the nest will be uncovered and the tally of hatched eggs, undeveloped eggs, and dead hatchlings will be recorded. If any hatchlings are found, they are either taken to be raised and released, or taken to research facilities. Ones that appear strong and healthy may instead be released to the ocean. Typically, those that lacked the strength to hatch and climb to the surface by that point would have died otherwise.
Hatchlings require the travel from their nest to the ocean in order to build up strength for the journey ahead, so interfering by helping it to the ocean actually lowers their chances of survival.[citation needed]
It is listed as Endangered under both Australia's Environment Protection and Biodiversity Conservation Act 1999 and Queensland's Nature Conservation Act 1992.
See also
- Chelonioidea. The sea turtle superfamily.
- Chelonia mydas. The green turtle.
- Dermochelys coriacea. The leatherback turtle.
- Eretmochelys imbricata. The hawksbill turtle.
- Lepidochelys kempii. The Kemp's Ridley turtle.
- Lepidochelys olivacea. The Olive Ridley turtle.
- Natator depressus. The Flatback Turtle.
References
- ^ http:www.widecast.org/sea/definitions.cfm[dead link]
- ^ <http://www.fws.gov/blackbeardisland/loggerhead.htm>
- ^ Dennis Hollier (August/September 2008). "Mapping the Void". Hana Hou!, Vol. 11, No. 4.
{{cite web}}: Check date values in:|date=(help) - ^ [1][dead link]
- ^ BBC NEWS | Science/Nature | Turtles return home after UK stay
- ^ Hochscheid, S., F. Bentivegna & G.C. Hays. (2005) "First records of dive durations for a hibernating sea turtle." Biol. Lett. 1(1): 82-6.
- ^ [2]
- ^ "Loggerhead Turtles in the Dalyan River, Mulğa Province, Turkey, 2004". seaturtle.org. Retrieved 2007-06-27.
- ^ Skoufas, George (July 2005). "Nesting and hatching success of the sea turtle Caretta caretta on Marathonissi island" (PDF). Belgian Journal of Zoology. 135 (2): 243-246. Retrieved 2009-01-02.
{{cite journal}}: Cite has empty unknown parameter:|coauthors=(help) - ^ "Conservation of the Akamas Peninsula (Cyprus)" (PDF), CONVENTION ON THE CONSERVATION OF EUROPEAN WILDLIFE AND NATURAL HABITATS, Strasbourg: Council of Europe, 29 November - 3 December-2004, retrieved 2009-01-02
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Bibliography
- Template:IUCN2006 Database entry includes a brief justification of why this species is endangered and the criteria used
- Connecticut Department of Environmental Protection - Endangered, Threatened & Special Concern Reptiles
- [3][dead link]
External links
- International: SWOT Report, volume 2 - Featuring the loggerhead nesting beaches of the world along with the most up-to-date information on the global status of loggerhead populations, conservation and natural history.
- International: ARKive - images and movies of the loggerhead turtle (Caretta caretta)
- U.S.: Loggerhead Turtle- by NOAA Fisheries Office of Protected Resources
- U.S.: Atlantic Loggerhead Sea Turtle Recovery Plan- a project of United States Fish & Wildlife Service and NOAA
- Florida: Loggerhead Sea Turtle- by U.S. Fish & Wildlife Service's North Florida Field Office
- Florida: Florida Sea Turtle information- Florida Fish and Wildlife Conservation Commission Fish and Wildlife Research Institute
- Georgia: Tybee Island, Georgia Sea Turtle Project
- Hawaii: Loggerhead Turtle- United States National Marine Sanctuary, Northwestern Hawaiian Islands
- Caribbean: Caribbean Conservation Corporation & Sea Turtle Survival League
- Greece: Go Zakynthos about Caretta Turtle
- Greece: Katelios Turtle Group, Kefalonia
- Greece: Sea Turtle Protection Society of Greece (Archelon)
- Africa: Marine Turtles-Africa- Convention on Migratory Species
- Brazil: TAMAR Marine Turtle Project
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Caretta caretta skull. Smithsonian Museum of Natural History.
