All About Pawikan - PDF

**Pawikan** Image result for sea turtle **Sea turtles** (superfamily **Chelonioidea**), sometimes called **marine turtles**, are reptiles of the order Testudines. The seven extant species of sea turtles are: the [green](https://en.wikipedia.org/wiki/Green_sea_turtle), [loggerhead](https://en.wikip...

**Pawikan** Image result for sea turtle **Sea turtles** (superfamily **Chelonioidea**), sometimes called **marine turtles**, are reptiles of the order Testudines. The seven extant species of sea turtles are: the [green](https://en.wikipedia.org/wiki/Green_sea_turtle), [loggerhead](https://en.wikipedia.org/wiki/Loggerhead_sea_turtle), [Kemp\'s ridley](https://en.wikipedia.org/wiki/Kemp%27s_ridley_sea_turtle), [olive ridley,](https://en.wikipedia.org/wiki/Olive_ridley_sea_turtle) [hawksbill](https://en.wikipedia.org/wiki/Hawksbill_sea_turtle), flatback, and [leatherback](https://en.wikipedia.org/wiki/Leatherback_sea_turtle). Description The majority of a sea turtle\'s body is protected by its shell. The turtle\'s shell is divided into two sections: carapace (the dorsal portion) and plastron (the ventral portion). The shell is made up of smaller plates called scutes. The [leatherback](https://en.wikipedia.org/wiki/Leatherback_sea_turtle) is the only sea turtle that does not have a hard shell. Instead, it bears a mosaic of bony plates beneath its leathery skin. In general, sea turtles have a more fusiform body plan than their terrestrial or freshwater counterparts. The reduced volume of a fusiform body means sea turtles can not retract their head, legs, and arms into their shells for protection like other turtles can. However this more stream-line body plan reduces drag in the water and allows the turtle to swim more easily. The leatherback is the largest species of sea turtle. Measuring 2--3 meters (6--9 ft) in length, and 1-1.5 m (3--5 ft) in width, weighing up to 700 kilograms (1500 lb). Other species are smaller, being mostly 60--120 cm (2--4 ft) and proportionally narrower. Taxonomy and evolution Sea turtles, along with other turtles and tortoises, are part of the order Testudines. All species except the leatherback are in the family Cheloniidae. The leatherback is the only extant member of the family Dermochelyidae. The origin of sea turtles goes back to the Late Jurassic (150 million years ago) with genera such as *Plesiochelys*, from Europe. In Africa, the first marine turtle is *Angolachelys*, from the Turonian of Angola. However, neither of these are related to extant sea turtles; the oldest representative of the lineage leading to these was *Desmatochelys padillai* , from the Early Cretaceous. A lineage of unrelated marine testudines, the pleurodire bothremydids, also survived well into the Cenozoic. Other pleurodires are also thought to have lived at sea, such as *Araripemys*. Sea turtles constitute a single radiation that became distinct from all other turtles at least 110 million years ago. **Cladogram** Below is a [cladogram](https://en.wikipedia.org/wiki/Cladogram) showing the phylogenetic relationships of living and extinct sea turtles in the Chelonioidea based on Peer and Lee (2005) +-----------------------------------------------------------------------+ | +------------------------------------------------------------------+ | | | **Phylogenetic relations of living and extinct chelonioid | | | | species** | | | +==================================================================+ | | | +------------------------------+------------------------------+ | | | | | [Panchelonioidea](https://en | +------------+------------+ | | | | | |.wikipedia.org/wiki/Panchelo | | | †*Toxochel | | | | | | | nioidea) | | | ys* | | | | | | | | +============+============+ | | | | | | | | | | | | | | | | | +------------+------------+ | | | | | | | | | †*Ctenoche | | | | | | | | | | lys* | | | | | | | | +------------+------------+ | | | | | | | | | | | | | | | | | +------------+------------+ | | | | | | | | **Chelonio | | | | | | | | | | idea** | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Panchelo | | | | | | | | | | niidae | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | †E | | | | | | | | | | uclastes | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | †P | | | | | | | | | | uppigerus< | | | | | | | | | | /em> | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Chel | | | | | | | | | | oniidae | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Pandermo | | | | | | | | | | chelys | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | †Proto | | | | | | | | | | stegidae | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | D | | | | | | | | | | ermochelyi | | | | | | | | | | dae | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | +------------+------------+ | | | | | | | | | | | | | | | | | +------------+------------+ | | | | | | | | | +==============================+==============================+ | | | | | | | | | | | +------------------------------+------------------------------+ | | | +------------------------------------------------------------------+ | +-----------------------------------------------------------------------+ Distribution and habitat Sea turtles can be found in oceans except for the polar regions. The flatback sea turtle is found solely on the northern coast of [Australia](https://en.wikipedia.org/wiki/Australia). The Kemp\'s ridley sea turtle is found solely in the [Gulf of Mexico](https://en.wikipedia.org/wiki/Gulf_of_Mexico) and along the [East Coast of the United States](https://en.wikipedia.org/wiki/East_Coast_of_the_United_States). Sea turtles are generally found in the waters over [continental shelves](https://en.wikipedia.org/wiki/Continental_shelf). During the first three to five years of life, sea turtles spend most of their time in the [pelagic zone](https://en.wikipedia.org/wiki/Pelagic_zone) floating in [seaweed](https://en.wikipedia.org/wiki/Seaweed) mats. Green sea turtles in particular are often found in *Sargassum* mats, in which they find shelter and food. Once the sea turtle has reached adulthood it moves closer to the shore. Females will come ashore to lay their eggs on sandy beaches during the nesting season. The habitat of a sea turtle has a significant influence on its morphology. Sea turtles are able to grow so large because of the immense size of their habitat: the ocean. The reason that sea turtles are much bigger than land tortoises and freshwater turtles is directly correlated with the vastness of the ocean, and the fact that they travel such far distances, especially the leatherback sea turtles. Having more room to live enables more room for growth. Life cycle  1\) Male and female turtles age in the ocean and migrate to shallow coastal water. 2) Turtles mate in the water near offshore nesting sites. 3) The adult male turtles return to the feeding sites in the water. 4) Female turtles cycle between mating and nesting. 5) Females lay their eggs. 6) When the season is over, female turtles return to feeding sites. 7) Baby turtles incubate for 60--80 days and hatch. 8) Newly hatched turtles emerge from nests and travel from the shore to the water. 9) Baby turtles mature in the ocean until they are ready to begin the cycle again. It takes decades for sea turtles to reach sexual maturity. Mature turtles may migrate thousands of miles to reach breeding sites. After mating at sea, adult female sea turtles return to land to lay their eggs. Different species of sea turtles exhibit various levels of philopatry. In the extreme case, females return to the beach where they hatched. This can take place every two to four years in maturity. The mature nesting female hauls herself onto the beach, nearly always at night, and finds suitable sand in which to create a nest. Using her hind flippers, she digs a circular hole 40 to 50 centimetres (16 to 20 in) deep. After the hole is dug, the female then starts filling the nest with her clutch of soft-shelled eggs. Depending on the species, a typical clutch may contain 50--350 eggs. After laying, she re-fills the nest with sand, re-sculpting and smoothing the surface, and then camouflaging the nest with vegetation until it is relatively undetectable visually. The whole process takes thirty to sixty minutes. She then returns to the ocean, leaving the eggs untended. Females may lay 1--8 clutches in a single season. Female sea turtles alternate between mating in the water and laying their eggs on land. Most sea turtle species nest individually. But ridley sea turtles come ashore en masse, known as an *arribada* (arrival). With the Kemp\'s ridley sea turtles this occurs during the day. Sea turtles have [temperature-dependent sex determination](https://en.wikipedia.org/wiki/Temperature-dependent_sex_determination), meaning the developing turtle\'s sex depends on the temperature it is exposed to. Warmer temperatures produce female hatchlings, while cooler temperatures produce male hatchlings. The eggs will incubate for 50--60 days. The eggs in one nest hatch together over a short period of time. The baby turtles break free of the egg shell, dig through the sand, and crawl into the sea. Most species of sea turtles hatch at night. However, the Kemp\'s ridley commonly hatches during the day. Turtle nests that hatch during the day are more vulnerable to predators, and may encounter more human activity on beach. Larger hatchlings have a higher probability of survival than smaller individuals, which can be explained by the fact that larger offspring are faster and thus less exposed to predation. Predators can only functionally intake so much; larger individuals are not targeted as often. A study conducted on this topic shows that body size is positively correlated with speed, so larger turtles are exposed to predators for a shorter amount of time. The fact that there is size dependent predation on [chelonians](https://en.wikipedia.org/wiki/Chelonia_(order)) has led to the evolutionary development of large body sizes. In 1987, Carr discovered that the young of green and loggerhead seaturtles spent a great deal of their [pelagic](https://en.wikipedia.org/wiki/Pelagic) lives in floating sargassummats. Within these mats, they found ample shelter and food. In the absence of sargassum, sea turtle young feed in the vicinity of upwelling\"fronts\". In 2007, Reich determined that green sea turtle hatchlings spend the first three to five years of their lives in [pelagic](https://en.wikipedia.org/wiki/Pelagic) waters. In the open ocean, pre-juveniles of this particular species were found to feed on [zooplankton](https://en.wikipedia.org/wiki/Zooplankton) and smaller [nekton](https://en.wikipedia.org/wiki/Nekton) before they are recruited into inshore seagrass meadows as obligate herbivores. Physiology **Osmoregulation** Sea turtles maintain an internal environment that is [hypotonic](https://en.wikipedia.org/wiki/Hypotonic) to the ocean. To maintain hypotonicity they must excrete excess salt ions. Like other marine reptiles, sea turtles rely on a specialized gland to rid the body of excess salt ions, because reptilian kidneys cannot produce urine with a higher ion concentration than sea water. All species of sea turtles have a [lachrymal gland](https://en.wikipedia.org/wiki/Lachrymal_gland) in the orbital cavity, capable of producing tears with a higher salt concentration than sea water. Leatherbacks face an increased osmotic challenge compared to other species of sea turtle, since their primary prey are jellyfish and other gelatinous plankton, whose fluids have the same concentration of salts as sea water. The much larger lachrymal gland found in leatherbacks may have evolved to cope with the higher intake of salts from their prey. A constant output of concentrated salty tears may be required to balance the input of salts from regular feeding, even considering leatherback tears can have a salt ion concentration almost twice that of other species of marine turtle.[^\[29\]^](https://en.wikipedia.org/wiki/Sea_turtle#cite_note-29) Hatchlings depend on drinking sea water immediately upon entering the ocean to replenish water lost during the hatching process. Salt gland functioning begins quickly after hatching, so that the young turtles can establish ion and water balance soon after entering the ocean. Survival and physiological performance hinge on immediate and efficient hydration following emergence from the nest. **Thermoregulation** Most sea turtles (those in family Cheloniidae) are poikilotherms. However the leatherback (family Dermochelyidae) are endothermsbecause they can maintain a body temperature 8 °C (14 °F) warmer than the ambient water. Green sea turtles in the relatively cooler Pacific are known to haul themselves out of the water on remote islands to bask in the sun. This behavior has only been observed in a few locations including the [Galapagos](https://en.wikipedia.org/wiki/Galapagos), Hawaii, [Europa Island](https://en.wikipedia.org/wiki/Europa_Island), and parts of Australia. **Diving physiology** Sea turtles are air breathing reptiles that have lungs, so they regularly surface to breathe. Sea turtles spend a majority of their time underwater, so they must be able to hold their breath for long periods. Dive duration largely depends on activity. A foraging turtle may typically spend 5--40 min under water while a sleeping sea turtle can remain under water for 4--7 hours. Remarkably, sea turtle respiration remains [aerobic](https://en.wikipedia.org/wiki/Cellular_respiration) for the vast majority of voluntary dive time. When a sea turtle is forcibly submerged (e.g. entangled in a trawl net) its diving endurance is substantially reduced, so it is more susceptible to drowning. When surfacing to breathe, a sea turtle can quickly refill its lungs with a single explosive exhalation and rapid inhalation. Their large lungs permit rapid exchange of oxygen and avoid trapping gases during deep dives. **Fluorescence** Gruber and Sparks (2015) have observed the first [fluorescence](https://en.wikipedia.org/wiki/Fluorescence) in a marine [tetrapod](https://en.wikipedia.org/wiki/Tetrapod) (four-limbed [vertebrates](https://en.wikipedia.org/wiki/Vertebrate)). Sea turtles are the first biofluorescent [reptile](https://en.wikipedia.org/wiki/Reptile) found in the wild. According to Gruber and Sparks (2015) [fluorescence](https://en.wikipedia.org/wiki/Fluorescence) is observed in an increasing number of marine creatures ([cnidarians](https://en.wikipedia.org/wiki/Cnidarian), [ctenophores](https://en.wikipedia.org/wiki/Ctenophora), [annelids](https://en.wikipedia.org/wiki/Annelid), [arthropods](https://en.wikipedia.org/wiki/Arthropod), and [chordates](https://en.wikipedia.org/wiki/Chordate)) and is now also considered to be widespread in [cartilaginous](https://en.wikipedia.org/wiki/Chondrichthyes) and [ray-finned](https://en.wikipedia.org/wiki/Actinopterygii) fishes. The two [marine biologists](https://en.wikipedia.org/wiki/Marine_biology) accidentally made the observation in the [Solomon Islands](https://en.wikipedia.org/wiki/Solomon_Islands) on a [hawksbill](https://en.wikipedia.org/wiki/Hawksbill) sea turtle, one of the rarest and most endangered turtle species in the ocean, during a night dive aimed to film the biofluorescence emitted by small [sharks](https://en.wikipedia.org/wiki/Shark) and [coral reefs](https://en.wikipedia.org/wiki/Coral_reef). The role of biofluorescence in marine organisms is often attributed to a strategy for attracting prey or perhaps a way to communicate. It could also serve as a way of defense or [camouflage](https://en.wikipedia.org/wiki/Camouflage) for the sea turtle hiding during night amongst other fluorescent organisms like corals. Fluorescent corals and sea creatures are best observed during night dives with a blue [LED](https://en.wikipedia.org/wiki/Light_emitting_diode) light and with a camera equipped with an orange [optical filter](https://en.wikipedia.org/wiki/Optical_filter) to capture only the fluorescence light. Ecology **Diet** The loggerhead, Kemp\'s ridley, olive ridley, and hawksbill sea turtles are omnivorous for their entire life. Omnivorous turtles may eat a wide variety of plant and animal life including [decapods](https://en.wikipedia.org/wiki/Decapoda), seagrasses, [seaweed](https://en.wikipedia.org/wiki/Seaweed), [sponges](https://en.wikipedia.org/wiki/Sponge), [mollusks](https://en.wikipedia.org/wiki/Mollusca), [cnidarians](https://en.wikipedia.org/wiki/Cnidaria), [echinoderms,](https://en.wikipedia.org/wiki/Echinoderm) worms and fish. However some species specialize on certain prey. The diet of green turtles changes with age. Juveniles are omnivorous, but as they mature they become exclusively herbivorous. This diet shift has an effect on the green turtle\'s morphology. Green sea turtles have a serrated jaw that is used to eat sea grass and algae. Leatherback turtles feed almost exclusively on jellyfish and help control jellyfish populations. Hawksbills principally eat sponges, which constitute 70--95% of their diets in the Caribbean. **Relationship with humans** Marine sea turtles are caught worldwide, although it is illegal to hunt most species in many countries. A great deal of intentional marine sea turtle harvests worldwide are for food. Many parts of the world have long considered sea turtles to be fine dining. [Ancient Chinese](https://en.wikipedia.org/wiki/History_of_China#Ancient_China) texts dating to the fifth century B.C.E. describe sea turtles as exotic delicacies. Many coastal communities around the world depend on sea turtles as a source of protein, often harvesting several sea turtles at once and keeping them alive on their backs until needed. Coastal peoples gather sea turtle eggs for consumption. To a much lesser extent, specific species of marine sea turtles are targeted not for their flesh, but for their shells. [Tortoiseshell](https://en.wikipedia.org/wiki/Tortoiseshell_material), a traditional decorative ornamental material used in Japan and China, comes from the [carapace](https://en.wikipedia.org/wiki/Carapace) scutes of the [hawksbill sea turtle](https://en.wikipedia.org/wiki/Hawksbill_sea_turtle). [Ancient Greeks](https://en.wikipedia.org/wiki/Ancient_Greek)and [ancient Romans](https://en.wikipedia.org/wiki/Ancient_Roman) processed sea turtle scutes (primarily from the hawksbill) for various articles and ornaments used by their elites, such as combs and brushes. The skin of the flippers is prized for use as shoes and assorted leather goods. The [Moche](https://en.wikipedia.org/wiki/Moche_(culture)) people of ancient [Peru](https://en.wikipedia.org/wiki/Peru) worshipped the sea and its animals. They often depicted sea turtles in their art. Leatherback sea turtles enjoy immunity from the sting of the deadly [box jellyfish](https://en.wikipedia.org/wiki/Box_jellyfish) and regularly eat them, helping keep tropical beaches safe for humans. Beach towns, such as Tortuguero, Costa Rica, have transitioned from a tourism industry that made profits from selling sea turtle meat and shells to an ecotourism-based economy. Tortuguero is considered to be the founding location of sea turtle conservation. In the 1960s the cultural demand for sea turtle meat, shells, and eggs was quickly killing the once abundant sea turtle populations that nested on the beach. The Caribbean Conservation Corporation began working with villagers to promote ecotourism as a permanent substitute to sea turtle hunting. Sea turtle nesting grounds became sustainable. Tourists love to come and visit the nesting grounds, although it causes a lot of stress to the turtles because all of the eggs can get damaged or harmed. Since the creation of a sea turtle, ecotourism-based economy, Tortugero annually houses thousands of tourists who visit the protected 22-mile (35 km) beach that hosts sea turtle walks and nesting grounds. **Importance to ecosystems** Sea turtles play key roles in two habitat types: oceans and beaches/dunes. In the oceans, sea turtles, especially green sea turtles, are one of very few creatures (manatees are another) that eat [sea grass](https://en.wikipedia.org/wiki/Sea_grass). Sea grass needs to be constantly cut short to help it grow across the sea floor. Sea turtle grazing helps maintain the health of the sea grass beds. Sea grass beds provide breeding and developmental grounds for numerous marine animals. Without them, many marine species humans harvest would be lost, as would the lower levels of the food chain. The reactions could result in many more marine species eventually becoming endangered or extinct. Sea turtles use beaches and the lower dunes to nest and lay their eggs. Beaches and dunes are a fragile habitat that depend on vegetation to protect against erosion. Eggs, hatched or unhatched, and hatchlings that fail to make it into the ocean are nutrient sources for dune vegetation. Along a 20-mile (32 km) stretch of beach on the east coast of Florida sea turtles lay over 150,000 lb (68,000 kg) of eggs in the sand. Dune vegetation is able to grow and become stronger with the nutrients from sea turtle nests. Stronger vegetation and root systems help to hold the sand in the dunes and help protect the beach from erosion. **Conservation status and threats** The [IUCN Red List](https://en.wikipedia.org/wiki/IUCN_Red_List_of_Endangered_Species) classifies three species of sea turtle as either \"Endangered\" or \"Critically Endangered\".An additional three species are classified as \"Vulnerable\".The flatback is considered as \"Data Deficient\", meaning that its conservation status is unclear due to lack of data. All species of sea turtle are listed in CITESAppendix I, restricting international trade of sea turtles and sea turtle products. However, the usefulness of global assessments for sea turtles has been questioned, particularly due to the presence of distinct genetic stocks and spatially separated regional management units (RMUs). Each RMU is subject to a unique set of threats that generally cross jurisdictional boundaries, resulting in some sub-populations of the same species\' showing recovery while others continue to decline. This has triggered the IUCN to conduct threat assessments at the sub-population level for some species recently. These new assessments have highlighted an unexpected mismatch between where conservation relevant science has been conducted on sea turtles, and where these is the greatest need for conservation. For example, as at August 2017, about 69% of studies using stable isotope analysis to understand the foraging distribution of sea turtles have been conducted in RMUs listed as \'Least Concern\' by the IUCN. Additionally, all populations of sea turtles that occur in United States waters are listed as threatened or endangered by the [US Endangered Species Act (ESA)](https://en.wikipedia.org/wiki/Endangered_Species_Act). The US listing status of the loggerhead is under review as of 2012. +-----------------------+-----------------------+-----------------------+ | | **IUCN Redlist** | **United States | | | | ESA\*** | +=======================+=======================+=======================+ | **Green** | Endangered | Endangered: | | | | populations in | | | | Florida and Pacific | | | | coast of Mexico | | | | populations | | | | | | | | Threatened: all other | | | | populations | +-----------------------+-----------------------+-----------------------+ | **Loggerhead** | Vulnerable | Endangered: NE | | | | Atlantic, | | | | Mediterranean, N | | | | Indian, N Pacific, S | | | | Pacific populations | | | | | | | | Threatened: NW | | | | Atlantic, S Atlantic, | | | | SE Indo-Pacific, SW | | | | Indian populations | +-----------------------+-----------------------+-----------------------+ | **Kemp\'s ridley** | Critically Endangered | Endangered: all | | | | populations | +-----------------------+-----------------------+-----------------------+ | **Olive ridley** | Vulnerable | Endangered: Pacific | | | | Coast of Mexico | | | | population | | | | | | | | Threatened: all other | | | | populations | +-----------------------+-----------------------+-----------------------+ | **Hawksbill** | Critically Endangered | Endangered: all | | | | populations | +-----------------------+-----------------------+-----------------------+ | **Flatback** | Data Deficient | N/A | +-----------------------+-----------------------+-----------------------+ | **Leatherback** | Vulnerable | Endangered: all | | | | populations | +-----------------------+-----------------------+-----------------------+ \*The ESA manages sea turtles by population not by species. **Management** In the Caribbean, researchers are having some success in assisting a comeback. In September 2007, [Corpus Christi, Texas](https://en.wikipedia.org/wiki/Corpus_Christi,_Texas), wildlife officials found 128 Kemp\'s ridley sea turtle nests on Texas beaches, a record number, including 81 on North [Padre Island](https://en.wikipedia.org/wiki/Padre_Island) ([Padre Island National Seashore](https://en.wikipedia.org/wiki/Padre_Island_National_Seashore)) and four on [Mustang Island](https://en.wikipedia.org/wiki/Mustang_Island). Wildlife officials released 10,594 Kemp\'s ridleys hatchlings along the Texas coast this year. The [Philippines](https://en.wikipedia.org/wiki/Philippines) has had several initiatives dealing with the issue of sea turtle conservation. In 2007, the province of Batangas declared the catching and eating of sea turtles (locally referred to as Pawikans) illegal. However, the law seems to have had little effect as sea turtle eggs are still in demand in [Batangan](https://en.wikipedia.org/wiki/Batangas#Name) markets. In September 2007, several Chinese [poachers](https://en.wikipedia.org/wiki/Poaching) were apprehended off the [Turtle Islands](https://en.wikipedia.org/wiki/Turtle_Islands,_Tawi-Tawi) in the country\'s southernmost province of Tawi-Tawi. The poachers had collected more than a hundred sea turtles, along with 10,000 sea turtle eggs. Evaluating the progress of conservation programs is difficult, because many sea turtle populations have not been assessed adequately. Most information on sea turtle populations comes from counting nests on beaches, but this doesn't provide an accurate picture of the whole sea turtle population. A 2010 United States National Research Council report concluded that more detailed information on sea turtles' life cycles, such as birth rates and mortality, is needed. Nest relocation may not be a useful conservation technique for sea turtles. In one study on the freshwater Arrau turtle (*Podocnemis expansa*) researchers examined the effects of nest relocation. They discovered that clutches of this freshwater turtle that were transplanted to a new location had higher mortality rates and more morphological abnormalities compared to non transplanted clutches. The results clearly demonstrate that humans should not manipulate or relocate clutches of that turtle, and impart strong evidence of the detrimental effects that human activity can cause. **Predators and disease** Most sea turtle mortality happens early in life. Sea turtles usually lay around one hundred eggs at a time, but on average only one of the eggs from the nest will survive to adulthood. Raccoons, foxes, and seabirds may raid nests or hatchlings may be eaten within minutes of hatching as they make their initial run for the ocean. Once in the water, they are susceptible to seabirds, large fish and even other turtles. Adult sea turtles have few predators. Large aquatic carnivores such as sharks and crocodiles are their biggest threats; however, reports of terrestrial predators attacking nesting females are not uncommon. [Jaguars](https://en.wikipedia.org/wiki/Jaguar) have been reported to smash into the turtle\'s shell with its paw, and scoop out the flesh. [Fibropapillomatosis](https://en.wikipedia.org/wiki/Fibropapillomatosis) disease causes tumors in sea turtles. While many of the things that endanger sea turtles are natural predators, increasingly many threats to the sea turtle species have arrived with the ever-growing presence of humans. **Bycatch** One of the most significant and contemporary threats to sea turtles comes from [bycatch](https://en.wikipedia.org/wiki/Bycatch) due to imprecise fishing methods. [Long-lining](https://en.wikipedia.org/wiki/Long-lining) has been identified as a major cause of accidental sea turtle death. There is also black-market demand for tortoiseshell for both decoration and supposed health benefits. Sea turtles must surface to breathe. Caught in a fisherman\'s net, they are unable to surface and thus drown. In early 2007, almost a thousand sea turtles were killed inadvertently in the [Bay of Bengal](https://en.wikipedia.org/wiki/Bay_of_Bengal) over the course of a few months after netting. However, some relatively inexpensive changes to fishing techniques, such as slightly larger hooks and traps from which sea turtles can escape, can dramatically cut the mortality rate. [Turtle Excluder Devices](https://en.wikipedia.org/wiki/Turtle_Excluder_Device) (TEDs) have reduced sea turtle bycatch in shrimp nets by 97 percent. **Beach development** Beach development is another area which threatens sea turtles. Since many sea turtles return to the same beach each time to nest, development can disrupt the cycle. There has been a movement to protect these areas, in some cases by special police. In some areas, such as the east coast of [Florida](https://en.wikipedia.org/wiki/Florida), conservationists dig up sea turtle eggs and relocate them to fenced nurseries to protect them from beach traffic. Since hatchlings find their way to the ocean by crawling towards the brightest horizon, they can become disoriented on developed stretches of coastline. Lighting restrictions can prevent lights from shining on the beach and confusing hatchlings. Sea turtle-safe lighting uses red or amber LED light, invisible to sea turtles, in place of white light. **Poaching** Another major threat to sea turtles is black-market trade in eggs and meat. This is a problem throughout the world, but especially a concern in [China](https://en.wikipedia.org/wiki/China), the [Philippines](https://en.wikipedia.org/wiki/Philippines), [India](https://en.wikipedia.org/wiki/India), [Indonesia](https://en.wikipedia.org/wiki/Indonesia) and the coastal nations of [Latin America](https://en.wikipedia.org/wiki/Latin_America). Estimates reach as high as 35,000 sea turtles killed a year in [Mexico](https://en.wikipedia.org/wiki/Mexico) and the same number in [Nicaragua](https://en.wikipedia.org/wiki/Nicaragua). Conservationists in Mexico and the United States have launched \"Don\'t Eat Sea Turtle\" campaigns in order to reduce this trade in sea turtle products. These campaigns have involved figures such as Dorismar, [Los Tigres del Norte](https://en.wikipedia.org/wiki/Los_Tigres_del_Norte) and Maná. Sea turtles are often consumed during the Catholic season of Lent, even though they are reptiles, not fish. Consequently, conservation organizations have written letters to the Pope asking that he declare sea turtles meat. **Marine debris** Another danger comes from [marine debris](https://en.wikipedia.org/wiki/Marine_debris), especially plastics which may be mistaken for jellyfish, and [abandoned fishing nets](https://en.wikipedia.org/wiki/Ghost_net) in which they can become entangled. **Climate change** Climate change may also cause a threat to sea turtles. Since sand temperature at nesting beaches defines the sex of a sea turtle while developing in the egg, there is concern that rising temperatures may produce too many females. However, more research is needed to understand how climate change might affect sea turtle gender distribution and what other possible threats it may pose. **Oil spills** Sea turtles are very vulnerable to oil pollution, both because of the oil\'s tendency to linger on the water\'s surface, and because oil can affect them at every stage of their life cycle. Oil can poison the sea turtles upon entering their digestive system. **Rehabilitation** Injured sea turtles are rescued and [rehabilitated](https://en.wikipedia.org/wiki/Wildlife_rehabilitation) (and, if possible, released back to the ocean) by professional organizations, such as the [Gumbo Limbo Nature Center](https://en.wikipedia.org/wiki/Gumbo_Limbo_Environmental_Complex) in Boca Raton, Florida, the Karen Beasley Sea Turtle Rescue and Rehabilitation Center in Surf City, North Carolina, and [Sea Turtles 911](https://en.wikipedia.org/wiki/Sea_Turtles_911) in Hainan, China. One rescued sea turtle, named Nickel for the coin that was found lodged in her throat, lives at the Shedd Aquarium in [Chicago](https://en.wikipedia.org/wiki/Chicago). **Symbiosis with barnacles** Sea Turtles are believed to have a [commensal](https://en.wikipedia.org/wiki/Commensalism) relationship with some [barnacles](https://en.wikipedia.org/wiki/Barnacle), in which the barnacles benefit from growing on turtles without harming them. Barnacles are small, hard shelled crustaceans found attached to multiple different substrates below or just above the ocean. The adult barnacle is a [sessile](https://en.wikipedia.org/wiki/Sessility_(zoology)) organism, however in its larval stage it is [planktonic](https://en.wikipedia.org/wiki/Plankton) and can move about the water column. The larval stage chooses where to settle and ultimately the habitat for its full adult life, which is typically between 5 and 10 years. However, estimates of age for a common sea turtle barnacle species, *Chelonibia testudinaria*, suggest that this species lives for at least 21 months, with individuals older than this uncommon. A favorite settlement for barnacle larvae is the shell or skin around the neck of sea turtles. The larvae glue themselves to the chosen spot, a thin layer of flesh is wrapped around them and a shell is secreted. Many species of barnacles can settle on any substrate, however some species of barnacles have an obligatory commensal relationship with specific animals, which makes finding a suitable location harder. Around 29 species of \"turtle barnacles\" have been recorded. However it is not solely on sea turtles that barnacles can be found; other organisms also serve as barnacle's settlements. These organisms include mollusks, whales, decapod crustaceans, manatees and several other groups related to these species. Sea turtle shells are an ideal habitat for adult barnacles for three reasons. Turtles tend to live long lives, \>70 years, so barnacles do not have to worry about host death. However, mortality in sea turtle barnacles is often driven by their host shedding the scutes on which the barnacle is attached, rather than the death of the turtle itself. Secondly, barnacles are [suspension feeders](https://en.wikipedia.org/wiki/Suspension_feeder). Sea turtles spend most of their lives swimming and following ocean currents and as water runs along the back of the turtle's shell it passes over the barnacles, providing an almost constant water flow and influx of food particles. Lastly, the long distances and inter-ocean travel these sea turtles swim throughout their lifetime offers the perfect mechanism for dispersal of barnacle larvae. Allowing the barnacle species to distribute themselves throughout global waters is a high fitness advantage of this commensalism. This relationship however is not truly commensal. While the barnacles are not directly [parasitic](https://en.wikipedia.org/wiki/Parasitism) to their hosts, they have negative effects to the turtles on which they choose to reside. The barnacles add extra weight and drag to the sea turtle, increasing the energy it needs for swimming and affecting its ability to capture prey, with the effect increasing with the quantity of barnacles affixed to its back. ##### Sea turtles are one of the Earth\'s most ancient creatures. The seven species that can be found today have been around for 110 million years, since the time of the dinosaurs. The sea turtle\'s shell, or \"carapace\" is streamlined for swimming through the water. Unlike other turtles, sea turtles cannot retract their legs and head into their shells. Their color varies between yellow, greenish and black depending on the species. DIET ---- What sea turtles eat depends on the subspecies, but some common items include jellyfish, seaweed, crabs, shrimp, sponges, snails, algae and mollusks. POPULATION ---------- It is difficult to find population numbers for sea turtles because male and juvenile sea turtles do not return to shore once they hatch and reach the ocean, which makes it hard to keep track of them. RANGE ----- Sea turtles are found in all warm and temperate waters throughout the world and migrate hundreds of miles between nesting and feeding grounds. Most sea turtles undergo long migrations, some as far as 1400 miles, between their feeding grounds and the beaches where they nest. BEHAVIOR -------- Sea turtles spend most of their lives in the water, where not much information can be gathered on their behavior. Most of what is known about sea turtle behavior is obtained by observing hatchlings and females that leave the water to lay eggs. Sea turtles, like salmon, will return to the same nesting grounds at which they were born. When females come to the shore they dig out a nest in the ground with their back flippers, bury their clutch of eggs and return to the ocean. After hatching, the young may take as long as a week to dig themselves out of the nest. They emerge at night, move toward the ocean and remain there, solitary, until it is time to mate. **REPRODUCTION** ---------------- **Temperature: **Temperatures of the sand where the turtles nest determine the sex of the turtle: below 85 degrees Fahrenheit (30ºC) is predominately male; above 85 degrees Fahrenheit (30ºC) is predominately female.\ **Mating Season: **March-October depending on the species.\ **Gestation:** 6-10 weeks.\ **Clutch size:** Between 70-190 eggs depending on the species.\ When the young hatch out of their eggs, they make their way to the ocean. Few survive to adulthood. From leatherbacks to loggerheads, six of the seven species of sea turtles are threatened or endangered at the hand of humans. Sadly, the fact is that they face many dangers as they travel the seas --- including accidental capture and entanglement in fishing gear (also known as bycatch), the loss of nesting and feeding sites to coastal development, poaching, and ocean pollution including plastic. These creatures are well-adapted to the ocean though they require air to survive. Their size varies greatly, depending upon species --- from the small Kemp's ridley, which weighs between 80--100 pounds, to the enormous leatherback, which can weigh more than 1,000 pounds. Sea turtles live in almost every ocean basin throughout the world, nesting on tropical and subtropical beaches. They migrate long distances to feed, often crossing entire oceans. Some loggerheads nest in Japan and migrate to Baja California Sur, Mexico to forage before returning home again. Leatherbacks are capable of withstanding the coldest water temperatures (often below 40˚F) and are found as far south as Chile and as far north as Alaska. They spend their entire lives at sea, except when adult females come ashore to lay eggs several times per season every 2 to 5 years. After about sixty days, [baby sea turtles](http://www.seeturtles.org/baby-turtles)(known as \"hatchlings\") emerge from their sandy nests and make their way to the ocean ---attracted to the distant horizon. The [juvenile turtles](http://www.seeturtles.org/juvenile-turtles) spend their first few years in the open oceans, eventually moving to protected bays, estuaries, and other nearshore waters as [adults](http://www.seeturtles.org/adult-sea-turtles). Each species relies on a different diet: greens eat sea grasses; leatherbacks feed on jellyfish and soft-bodied animals; loggerheads eat heavy-shelled animals such as crabs and clams; hawksbills rely on sponges and other invertebrates; and the Kemp's ridley prefers crabs. These ancient creatures have been on Earth for more than 100 million years --- even surviving the dinosaurs when they became extinct 65 million years ago. Among the threats these marine reptiles face are entanglement, habitat loss, and consumption of their eggs and meat. Sea turtles often drown when caught in fishing gear, both nets and longlines. Coastal development can destroy important nesting sites, impact coral reefs, and artificial light from houses and other buildings attracts hatchlings away from the ocean. Pollution like plastic bags are often mistaken for food such as jellyfish and ingested, which blocks their intestines and potentially kills them. In some countries, they are hunted for their meat and shells and their eggs are eaten. Seven different species of sea (or marine) turtles grace our ocean waters, from the shallow seagrass beds of the Indian Ocean, to the colorful reefs of the Coral Triangle, and even the sandy beaches of the Eastern Pacific. WWF's work on sea turtles focuses on five of those species: green, hawksbill, loggerhead, leatherback and olive ridley. Human activities have tipped the scales against the survival of these ancient mariners. Nearly all species of sea turtle are classified as Endangered. Slaughtered for their eggs, meat, skin and shells, sea turtles suffer from poaching and over-exploitation. They also face habitat destruction and accidental capture in fishing gear. Climate change has an impact on turtle nesting sites. It alters sand temperatures, which then affects the sex of hatchlings. WWF is committed to stop the decline of sea turtles and work for the recovery of the species. We work to secure environments in which both turtles---and the people that depend upon them---can survive into the future. Sea turtles are a fundamental link in marine ecosystems. They help maintain the health of sea grass beds and coral reefs that benefit commercially valuable species such as shrimp, lobster and tuna. Sea turtles are the live representatives of a group of reptiles that have existed on Earth and traveled our seas for the last 100 million years. Turtles have major cultural significance and tourism value.  Sea turtles journey between land and sea and swim thousands of ocean miles during their long lifetimes, exposing them to countless threats. They wait decades until they can reproduce, returning to the same beaches where they were born to lay their eggs, few of which will yield hatchlings that survive their first year of life. Beyond these significant natural challenges, sea turtles face multiple threats caused by humans. ### ### ### ### ### ### [BY CATCH](https://www.worldwildlife.org/threats/bycatch) Worldwide, hundreds of thousands of sea turtles are accidentally caught in shrimp trawl nets, on longline hooks and in fishing gillnets every year. They become fisheries bycatch\--unintended catch of non-target species.  Sea turtles need to reach the surface to breathe and therefore many drown once caught. Incidental capture by fishing gear is the greatest threat to most sea turtles, especially endangered loggerheads, greens and leatherbacks. This threat is increasing as fishing activity expands. ### [OVERHARVESTING AND ILLEGAL TRADE](https://www.worldwildlife.org/threats/illegal-wildlife-trade) Sea turtles continue to be harvested unsustainably both for human consumption and trade of their parts. Turtle meat and eggs are a source of food and income for many people around the world. Some also kill turtles for medicine and religious ceremonies. Tens of thousands of sea turtles are lost this way every year, devastating populations of already endangered greens and hawksbills. Killing of turtles for both domestic and international markets continues as well. While international trade in all sea turtle species and their parts is prohibited under the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES), illegal trafficking persists. ### HABITAT LOSS Sea turtles are dependent on beaches for nesting. Uncontrolled coastal development, vehicle traffic on beaches and other human activities have directly destroyed or disturbed sea turtle nesting beaches around the world. Turtle feeding grounds such as coral reefs and sea grass beds are damaged and destroyed by activities onshore, including sedimentation from clearing of land and nutrient run-off from agriculture. ### [CLIMATE CHANGE](https://www.worldwildlife.org/threats/effects-of-climate-change) All stages of a sea turtle's life are affected by environmental conditions such as temperature---even the sex of offspring. Unusually warm temperatures caused by climate change are disrupting the normal ratios, resulting in fewer male hatchlings.  Warmer sea surface temperatures can also lead to the loss of important foraging grounds for sea turtles, while increasingly severe storms and sea level rise can destroy critical nesting beaches and damage nests. **7 FACTS ABOUT SEA TURTLES:** 1. Green; Hawksbill; Loggerhead; Olive Ridley and Leatherback. 2. They can only hold their breath for approximately 4-7 hours. (Notice tiny heads of Sea Turtles coming up for air? Aren't they cute and quite exciting to watch? ) 3. The largest measured almost 3 meters (9 feet) from tip to tail and weighed 970 kg. 4. When mother sea turtles are about to lay their eggs, they always go back to the beach where they were born years ago. They have the ability to locate their home beach. Even if they have travelled miles away, they come back one day just to lay their eggs. 5. 6. 7. Warmer temperature usually produces mostly female hatchlings; while cooler temperature produces mostly male hatchlings. The majority of a sea turtle\'s body is protected by its shell. The turtle\'s shell is divided into two sections: carapace (the dorsal portion) and plastron (the ventral portion). The shell is made up of smaller plates called scutes. The [leatherback](https://en.wikipedia.org/wiki/Leatherback_sea_turtle) is the only sea turtle that does not have a hard shell. Instead, it bears a mosaic of bony plates beneath its leathery skin. In general, sea turtles have a more fusiform body plan than their terrestrial or freshwater counterparts. The reduced volume of a fusiform body means sea turtles can not retract their head, legs, and arms into their shells for protection like other turtles can. However this more stream-line body plan reduces drag in the water and allows the turtle to swim more easily. The leatherback is the largest species of sea turtle. Measuring 2--3 meters (6--9 ft) in length, and 1-1.5 m (3--5 ft) in width, weighing up to 700 kilograms (1500 lb). Other species are smaller, being mostly 60--120 cm (2--4 ft) and proportionally narrower. Sea turtles, along with other turtles and tortoises, are part of the order Testudines. All species except the leatherback are in the family Cheloniidae. The leatherback is the only extant member of the family Dermochelyidae. The origin of sea turtles goes back to the Late Jurassic (150 million years ago) with genera such as *Plesiochelys*, from Europe. In Africa, the first marine turtle is *Angolachelys*, from the Turonian of Angola. However, neither of these are related to extant sea turtles; the oldest representative of the lineage leading to these was *Desmatochelys padillai* , from the Early Cretaceous. A lineage of unrelated marine testudines, the pleurodire bothremydids, also survived well into the Cenozoic. Other pleurodires are also thought to have lived at sea, such as *Araripemys*. Sea turtles constitute a single radiation that became distinct from all other turtles at least 110 million years ago. Sea turtles can be found in oceans except for the polar regions. The flatback sea turtle is found solely on the northern coast of [Australia](https://en.wikipedia.org/wiki/Australia). The Kemp\'s ridley sea turtle is found solely in the [Gulf of Mexico](https://en.wikipedia.org/wiki/Gulf_of_Mexico) and along the [East Coast of the United States](https://en.wikipedia.org/wiki/East_Coast_of_the_United_States). Sea turtles are generally found in the waters over [continental shelves](https://en.wikipedia.org/wiki/Continental_shelf). During the first three to five years of life, sea turtles spend most of their time in the [pelagic zone](https://en.wikipedia.org/wiki/Pelagic_zone) floating in [seaweed](https://en.wikipedia.org/wiki/Seaweed) mats. Green sea turtles in particular are often found in *Sargassum* mats, in which they find shelter and food. Once the sea turtle has reached adulthood it moves closer to the shore. Females will come ashore to lay their eggs on sandy beaches during the nesting season. The habitat of a sea turtle has a significant influence on its morphology. Sea turtles are able to grow so large because of the immense size of their habitat: the ocean. The reason that sea turtles are much bigger than land tortoises and freshwater turtles is directly correlated with the vastness of the ocean, and the fact that they travel such far distances, especially the leatherback sea turtles. Having more room to live enables more room for growth. It takes decades for sea turtles to reach sexual maturity. Mature turtles may migrate thousands of miles to reach breeding sites. After mating at sea, adult female sea turtles return to land to lay their eggs. Different species of sea turtles exhibit various levels of philopatry. In the extreme case, females return to the beach where they hatched. This can take place every two to four years in maturity. The mature nesting female hauls herself onto the beach, nearly always at night, and finds suitable sand in which to create a nest. Using her hind flippers, she digs a circular hole 40 to 50 centimetres (16 to 20 in) deep. After the hole is dug, the female then starts filling the nest with her clutch of soft-shelled eggs. Depending on the species, a typical clutch may contain 50--350 eggs. After laying, she re-fills the nest with sand, re-sculpting and smoothing the surface, and then camouflaging the nest with vegetation until it is relatively undetectable visually. The whole process takes thirty to sixty minutes. She then returns to the ocean, leaving the eggs untended. Females may lay 1--8 clutches in a single season. Female sea turtles alternate between mating in the water and laying their eggs on land. Most sea turtle species nest individually. But ridley sea turtles come ashore en masse, known as an *arribada* (arrival). With the Kemp\'s ridley sea turtles this occurs during the day. Sea turtles have [temperature-dependent sex determination](https://en.wikipedia.org/wiki/Temperature-dependent_sex_determination), meaning the developing turtle\'s sex depends on the temperature it is exposed to. Warmer temperatures produce female hatchlings, while cooler temperatures produce male hatchlings. The eggs will incubate for 50--60 days. The eggs in one nest hatch together over a short period of time. The baby turtles break free of the egg shell, dig through the sand, and crawl into the sea. Most species of sea turtles hatch at night. However, the Kemp\'s ridley commonly hatches during the day. Turtle nests that hatch during the day are more vulnerable to predators, and may encounter more human activity on beach. Larger hatchlings have a higher probability of survival than smaller individuals, which can be explained by the fact that larger offspring are faster and thus less exposed to predation. Predators can only functionally intake so much; larger individuals are not targeted as often. A study conducted on this topic shows that body size is positively correlated with speed, so larger turtles are exposed to predators for a shorter amount of time. The fact that there is size dependent predation on [chelonians](https://en.wikipedia.org/wiki/Chelonia_(order)) has led to the evolutionary development of large body sizes. In 1987, Carr discovered that the young of green and loggerhead seaturtles spent a great deal of their [pelagic](https://en.wikipedia.org/wiki/Pelagic) lives in floating sargassummats. Within these mats, they found ample shelter and food. In the absence of sargassum, sea turtle young feed in the vicinity of upwelling\"fronts\".In 2007, Reich determined that green sea turtle hatchlings spend the first three to five years of their lives in [pelagic](https://en.wikipedia.org/wiki/Pelagic) waters. In the open ocean, pre-juveniles of this particular species were found to feed on [zooplankton](https://en.wikipedia.org/wiki/Zooplankton) and smaller [nekton](https://en.wikipedia.org/wiki/Nekton) before they are recruited into inshore seagrass meadows as obligate herbivores. Most sea turtle mortality happens early in life. Sea turtles usually lay around one hundred eggs at a time, but on average only one of the eggs from the nest will survive to adulthood. Raccoons, foxes, and seabirds may raid nests or hatchlings may be eaten within minutes of hatching as they make their initial run for the ocean. Once in the water, they are susceptible to seabirds, large fish and even other turtles. Adult sea turtles have few predators. Large aquatic carnivores such as sharks and crocodiles are their biggest threats; however, reports of terrestrial predators attacking nesting females are not uncommon. [Jaguars](https://en.wikipedia.org/wiki/Jaguar) have been reported to smash into the turtle\'s shell with its paw, and scoop out the flesh. [Fibropapillomatosis](https://en.wikipedia.org/wiki/Fibropapillomatosis) disease causes tumors in sea turtles. While many of the things that endanger sea turtles are natural predators, increasingly many threats to the sea turtle species have arrived with the ever-growing presence of humans. Sea Turtles are believed to have a [commensal](https://en.wikipedia.org/wiki/Commensalism) relationship with some [barnacles](https://en.wikipedia.org/wiki/Barnacle), in which the barnacles benefit from growing on turtles without harming them. Barnacles are small, hard shelled crustaceans found attached to multiple different substrates below or just above the ocean. The adult barnacle is a [sessile](https://en.wikipedia.org/wiki/Sessility_(zoology)) organism, however in its larval stage it is [planktonic](https://en.wikipedia.org/wiki/Plankton) and can move about the water column. The larval stage chooses where to settle and ultimately the habitat for its full adult life, which is typically between 5 and 10 years. However, estimates of age for a common sea turtle barnacle species, *Chelonibia testudinaria*, suggest that this species lives for at least 21 months, with individuals older than this uncommon. A favorite settlement for barnacle larvae is the shell or skin around the neck of sea turtles. The larvae glue themselves to the chosen spot, a thin layer of flesh is wrapped around them and a shell is secreted. Many species of barnacles can settle on any substrate, however some species of barnacles have an obligatory commensal relationship with specific animals, which makes finding a suitable location harder. Around 29 species of \"turtle barnacles\" have been recorded. However it is not solely on sea turtles that barnacles can be found; other organisms also serve as barnacle's settlements. These organisms include mollusks, whales, decapod crustaceans, manatees and several other groups related to these species. Sea turtle shells are an ideal habitat for adult barnacles for three reasons. Turtles tend to live long lives, \>70 years, so barnacles do not have to worry about host death. However, mortality in sea turtle barnacles is often driven by their host shedding the scutes on which the barnacle is attached, rather than the death of the turtle itself. Secondly, barnacles are [suspension feeders](https://en.wikipedia.org/wiki/Suspension_feeder). Sea turtles spend most of their lives swimming and following ocean currents and as water runs along the back of the turtle's shell it passes over the barnacles, providing an almost constant water flow and influx of food particles. Lastly, the long distances and inter-ocean travel these sea turtles swim throughout their lifetime offers the perfect mechanism for dispersal of barnacle larvae. Allowing the barnacle species to distribute themselves throughout global waters is a high fitness advantage of this commensalism. This relationship however is not truly commensal. While the barnacles are not directly [parasitic](https://en.wikipedia.org/wiki/Parasitism) to their hosts, they have negative effects to the turtles on which they choose to reside. The barnacles add extra weight and drag to the sea turtle, increasing the energy it needs for swimming and affecting its ability to capture prey, with the effect increasing with the quantity of barnacles affixed to its back.