Eretmochelys
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The hawksbill sea turtle (''Eretmochelys imbricata'') is a critically endangered
sea turtle Sea turtles (superfamily Chelonioidea), 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, loggerhe ...
belonging to the family
Cheloniidae 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 t ...
. It is the only extant
species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriat ...
in the
genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...
''Eretmochelys''. The species has a global distribution, that is largely limited to tropical and subtropical marine and estuary ecosystems. The hawksbill's appearance is similar to that of other marine turtles. In general, it has a flattened body shape, a protective
carapace A carapace is a dorsal (upper) section of the exoskeleton or shell in a number of animal groups, including arthropods, such as crustaceans and arachnids, as well as vertebrates, such as turtles and tortoises. In turtles and tortoises, the unde ...
, and flipper-like limbs, adapted for swimming in the open ocean. ''E. imbricata'' is easily distinguished from other sea turtles by its sharp, curving
beak The beak, bill, or rostrum is an external anatomical structure found mostly in birds, but also in turtles, non-avian dinosaurs and a few mammals. A beak is used for eating, preening, manipulating objects, killing prey, fighting, probing for fo ...
with prominent tomium, and the saw-like appearance of its shell margins. Hawksbill shells slightly change colors, depending on water temperature. While this turtle lives part of its life in the open ocean, it spends more time in shallow
lagoon A lagoon is a shallow body of water separated from a larger body of water by a narrow landform, such as reefs, barrier islands, barrier peninsulas, or isthmuses. Lagoons are commonly divided into '' coastal lagoons'' (or ''barrier lagoons ...
s and
coral reef A coral reef is an underwater ecosystem characterized by reef-building corals. Reefs are formed of Colony (biology), colonies of coral polyp (zoology), polyps held together by calcium carbonate. Most coral reefs are built from stony corals, wh ...
s. The
World Conservation Union The International Union for Conservation of Nature (IUCN; officially International Union for Conservation of Nature and Natural Resources) is an international organization working in the field of nature conservation and sustainable use of natur ...
, primarily as a result of human fishing practices, classifies ''E. imbricata'' as critically endangered. Hawksbill shells were the primary source of
tortoiseshell material Tortoiseshell or tortoise shell is a material produced from the shells of the larger species of tortoise and turtle, mainly the hawksbill sea turtle, which is a critically endangered species according to the IUCN Red List largely because of it ...
used for decorative purposes. The
Convention on International Trade in Endangered Species CITES (shorter name for the Convention on International Trade in Endangered Species of Wild Fauna and Flora, also known as the Washington Convention) is a multilateral treaty to protect endangered plants and animals from the threats of intern ...
(CITES) regulates the international trade of hawksbill sea turtles and products derived from them.


Taxonomy

Linnaeus described the hawksbill sea turtle as ''Testudo imbricata'' in 1766, in the
12th edition 1 (one, unit, unity) is a number representing a single or the only entity. 1 is also a numerical digit and represents a single unit of counting or measurement. For example, a line segment of ''unit length'' is a line segment of length 1. ...
of his ''
Systema Naturae ' (originally in Latin written ' with the ligature æ) is one of the major works of the Swedish botanist, zoologist and physician Carl Linnaeus (1707–1778) and introduced the Linnaean taxonomy. Although the system, now known as binomial ...
''. In 1843, Austrian zoologist
Leopold Fitzinger Leopold Joseph Franz Johann Fitzinger (13 April 1802 – 20 September 1884) was an Austrian zoologist. Fitzinger was born in Vienna and studied botany at the University of Vienna under Nikolaus Joseph von Jacquin. He worked at the Vienna Natur ...
moved it into the genus ''Eretmochelys''. In 1857, the species was temporarily misdescribed as ''Eretmochelys imbricata squamata''. Neither the IUCN nor the United States Endangered Species Act assessment processes recognize any formal subspecies, but instead recognize one globally distributed species with populations, subpopulations, or regional management units. Fitzinger derived the genus name ''Eretmochelys'' from the
Ancient Greek Ancient Greek includes the forms of the Greek language used in ancient Greece and the ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (), Dark Ages (), the Archaic pe ...
roots ''eretmo'' and ''chelys'', corresponding to " oar" and "turtle", respectively, in reference to the turtles' oar-like front flippers. The species name ''imbricata'' is
Latin Latin (, or , ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through ...
, corresponding to the English term imbricate, in reference to the turtles' shingle-like, overlapping carapace scutes.


Description

Adult hawksbill sea turtles typically grow to in length, weighing around on average. The heaviest hawksbill ever captured weighed . The turtle's shell, or carapace, has an amber background patterned with an irregular combination of light and dark streaks, with predominantly black and mottled-brown colors radiating to the sides. Several characteristics of the hawksbill sea turtle distinguish it from other sea turtle species. Its elongated, tapered head ends in a beak-like mouth (from which its common name is derived), and its beak is more sharply pronounced and hooked than others. The hawksbill's forelimbs have two visible claws on each flipper. One of the hawksbill's more easily distinguished characteristics is the pattern of thick
scute A scute or scutum (Latin: ''scutum''; plural: ''scuta'' "shield") is a bony external plate or scale overlaid with horn, as on the shell of a turtle, the skin of crocodilians, and the feet of birds. The term is also used to describe the anterior po ...
s that make up its carapace. While its carapace has five central scutes and four pairs of
lateral Lateral is a geometric term of location which may refer to: Healthcare *Lateral (anatomy), an anatomical direction * Lateral cricoarytenoid muscle * Lateral release (surgery), a surgical procedure on the side of a kneecap Phonetics *Lateral co ...
scutes like several members of its family, ''E. imbricata'' posterior scutes overlap in such a way as to give the rear margin of its carapace a serrated look, similar to the edge of a saw or a steak knife. The turtle's carapace can reach almost in length. The hawksbill appears to frequently employ its sturdy shell to insert its body into tight spaces in reefs. Crawling with an alternating
gait Gait is the pattern of movement of the limbs of animals, including humans, during locomotion over a solid substrate. Most animals use a variety of gaits, selecting gait based on speed, terrain, the need to maneuver, and energetic efficiency. ...
, hawksbill tracks left in the sand are asymmetrical. In contrast, the
green sea turtle The green sea turtle (''Chelonia mydas''), also known as the green turtle, black (sea) turtle or Pacific green turtle, is a species of large sea turtle of the family Cheloniidae. It is the only species in the genus ''Chelonia''. Its range exten ...
and the
leatherback turtle The leatherback sea turtle (''Dermochelys coriacea''), sometimes called the lute turtle or leathery turtle or simply the wikt:luth#English, luth, is the largest of all living turtles and the heaviest non-crocodilian reptile, reaching lengths of ...
have a more symmetrical gait. Due to its consumption of venomous
cnidaria Cnidaria () is a phylum under kingdom Animalia containing over 11,000 species of aquatic animals found both in freshwater and marine environments, predominantly the latter. Their distinguishing feature is cnidocytes, specialized cells that ...
ns, hawksbill sea turtle flesh can become
toxic Toxicity is the degree to which a chemical substance or a particular mixture of substances can damage an organism. Toxicity can refer to the effect on a whole organism, such as an animal, bacterium, or plant, as well as the effect on a sub ...
. The hawksbill is biofluorescent and is the first reptile recorded with this characteristic. It is unknown if the effect is due to the turtle's diet, which includes biofluorescent organisms like the hard coral ''
Physogyra lichtensteini ''Physogyra'' is a genus of cnidarians Cnidaria () is a phylum under kingdom Animalia containing over 11,000 species of aquatic animals found both in freshwater and marine environments, predominantly the latter. Their distinguishing feature ...
''. Males have more intense pigmentation than females, and a behavioural role of these differences is speculated. Tortue imbriqueeld4.jpg, alt=Photo from above of swimming turtle, with four outstretched flippers and faceted shell, Carapace's serrated margin and overlapping
scute A scute or scutum (Latin: ''scutum''; plural: ''scuta'' "shield") is a bony external plate or scale overlaid with horn, as on the shell of a turtle, the skin of crocodilians, and the feet of birds. The term is also used to describe the anterior po ...
s are evident in this individual Hawksbill turtle doeppne-081.jpg, alt=Profile photo of animal head with prominent beak protruding above lower jaw, a faceted head covering surrounds the eye, Close-up of the hawksbill's distinctive beak Fluorescent Turtle.jpg, Fluorescent markings on Hawksbill sea turtle Hawksbill Turtle on the GBR.webm, A Hawksbill turtle swims past a group of divers on the Great Barrier Reef, Australia


Distribution

Hawksbill sea turtles have a wide range, found predominantly in tropical reefs of the
Indian Indian or Indians may refer to: Peoples South Asia * Indian people, people of Indian nationality, or people who have an Indian ancestor ** Non-resident Indian, a citizen of India who has temporarily emigrated to another country * South Asia ...
,
Pacific The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean (or, depending on definition, to Antarctica) in the south, and is bounded by the contine ...
, and
Atlantic The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth's surface and about 29% of its water surface area. It is known to separate the " Old World" of Africa, Europe ...
Oceans. Of all the sea turtle species, ''E. imbricata'' is the one most associated with warm tropical waters. Two significant subpopulations are known, in the Atlantic and Indo-Pacific.


Atlantic subpopulation

In the Atlantic, hawksbill populations range as far west as the
Gulf of Mexico The Gulf of Mexico ( es, Golfo de México) is an ocean basin and a marginal sea of the Atlantic Ocean, largely surrounded by the North American continent. It is bounded on the northeast, north and northwest by the Gulf Coast of the United ...
and as far southeast as the
Cape of Good Hope The Cape of Good Hope ( af, Kaap die Goeie Hoop ) ;''Kaap'' in isolation: pt, Cabo da Boa Esperança is a rocky headland on the Atlantic coast of the Cape Peninsula in South Africa. A common misconception is that the Cape of Good Hope is ...
in
South Africa South Africa, officially the Republic of South Africa (RSA), is the southernmost country in Africa. It is bounded to the south by of coastline that stretch along the South Atlantic and Indian Oceans; to the north by the neighbouring coun ...
. They live off the
Brazil Brazil ( pt, Brasil; ), officially the Federative Republic of Brazil (Portuguese: ), is the largest country in both South America and Latin America. At and with over 217 million people, Brazil is the world's fifth-largest country by area ...
ian coast (specifically
Bahia Bahia ( , , ; meaning "bay") is one of the 26 states of Brazil, located in the Northeast Region of the country. It is the fourth-largest Brazilian state by population (after São Paulo, Minas Gerais, and Rio de Janeiro) and the 5th-larges ...
,
Fernando de Noronha Fernando de Noronha () is an archipelago in the Atlantic Ocean, part of the State of Pernambuco, Brazil, and located off the Brazilian coast. It consists of 21 islands and islets, extending over an area of . Only the eponymous main island is in ...
) through southern
Florida Florida is a state located in the Southeastern region of the United States. Florida is bordered to the west by the Gulf of Mexico, to the northwest by Alabama, to the north by Georgia, to the east by the Bahamas and Atlantic Ocean, and ...
and
Virginia Virginia, officially the Commonwealth of Virginia, is a state in the Mid-Atlantic and Southeastern regions of the United States, between the Atlantic Coast and the Appalachian Mountains. The geography and climate of the Commonwealth are ...
waters. In the
Caribbean The Caribbean (, ) ( es, El Caribe; french: la Caraïbe; ht, Karayib; nl, De Caraïben) is a region of the Americas that consists of the Caribbean Sea, its islands (some surrounded by the Caribbean Sea and some bordering both the Caribbean ...
, the main nesting beaches are in the
Lesser Antilles The Lesser Antilles ( es, link=no, Antillas Menores; french: link=no, Petites Antilles; pap, Antias Menor; nl, Kleine Antillen) are a group of islands in the Caribbean Sea. Most of them are part of a long, partially volcanic island arc be ...
,
Barbados Barbados is an island country in the Lesser Antilles of the West Indies, in the Caribbean region of the Americas, and the most easterly of the Caribbean Islands. It occupies an area of and has a population of about 287,000 (2019 estima ...
, Guadeloupe, Tortuguero in
Costa Rica Costa Rica (, ; ; literally "Rich Coast"), officially the Republic of Costa Rica ( es, República de Costa Rica), is a country in the Central American region of North America, bordered by Nicaragua to the north, the Caribbean Sea to the no ...
, and the Yucatan. They feed in the waters off
Cuba Cuba ( , ), officially the Republic of Cuba ( es, República de Cuba, links=no ), is an island country comprising the island of Cuba, as well as Isla de la Juventud and several minor archipelagos. Cuba is located where the northern Caribb ...
and around Mona Island near
Puerto Rico Puerto Rico (; abbreviated PR; tnq, Boriken, ''Borinquen''), officially the Commonwealth of Puerto Rico ( es, link=yes, Estado Libre Asociado de Puerto Rico, lit=Free Associated State of Puerto Rico), is a Caribbean island and unincorporated ...
, among other places.


Indo-Pacific subpopulation

In the
Indian Ocean The Indian Ocean is the third-largest of the world's five oceanic divisions, covering or ~19.8% of the water on Earth's surface. It is bounded by Asia to the north, Africa to the west and Australia to the east. To the south it is bounded by ...
, hawksbills are a common sight along the east coast of Africa, including the seas surrounding
Madagascar Madagascar (; mg, Madagasikara, ), officially the Republic of Madagascar ( mg, Repoblikan'i Madagasikara, links=no, ; french: République de Madagascar), is an island country in the Indian Ocean, approximately off the coast of East Afric ...
and nearby island groups. Hawksbills are also common along the southern Asian coast, including the
Persian Gulf The Persian Gulf ( fa, خلیج فارس, translit=xalij-e fârs, lit=Gulf of Fars, ), sometimes called the ( ar, اَلْخَلِيْجُ ٱلْعَرَبِيُّ, Al-Khalīj al-ˁArabī), is a mediterranean sea in Western Asia. The bo ...
, the
Red Sea The Red Sea ( ar, البحر الأحمر - بحر القلزم, translit=Modern: al-Baḥr al-ʾAḥmar, Medieval: Baḥr al-Qulzum; or ; Coptic: ⲫⲓⲟⲙ ⲛ̀ϩⲁϩ ''Phiom Enhah'' or ⲫⲓⲟⲙ ⲛ̀ϣⲁⲣⲓ ''Phiom ǹšari''; ...
, and the
Indian subcontinent The Indian subcontinent is a physiographical region in Southern Asia. It is situated on the Indian Plate, projecting southwards into the Indian Ocean from the Himalayas. Geopolitically, it includes the countries of Bangladesh, Bhutan, In ...
and
Southeast Asia Southeast Asia, also spelled South East Asia and South-East Asia, and also known as Southeastern Asia, South-eastern Asia or SEA, is the geographical south-eastern region of Asia, consisting of the regions that are situated south of mainland ...
coasts. They are present across the
Malay Archipelago The Malay Archipelago ( Indonesian/ Malay: , tgl, Kapuluang Malay) is the archipelago between mainland Indochina and Australia. It has also been called the " Malay world," " Nusantara", "East Indies", Indo-Australian Archipelago, Spices Arc ...
and northern
Australia Australia, officially the Commonwealth of Australia, is a sovereign country comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands. With an area of , Australia is the largest country by ...
. Their
Pacific The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean (or, depending on definition, to Antarctica) in the south, and is bounded by the contine ...
range is limited to the ocean's tropical and subtropical regions. In the west, it extends from the southwestern tips of the
Korean Peninsula Korea ( ko, 한국, or , ) is a peninsular region in East Asia. Since 1945, it has been divided at or near the 38th parallel, with North Korea (Democratic People's Republic of Korea) comprising its northern half and South Korea (Republic ...
and the
Japanese Archipelago The Japanese archipelago (Japanese: 日本列島, ''Nihon rettō'') is a group of 6,852 islands that form the country of Japan, as well as the Russian island of Sakhalin. It extends over from the Sea of Okhotsk in the northeast to the East Chin ...
south to northern
New Zealand New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and over 700 smaller islands. It is the sixth-largest island coun ...
. The
Philippines The Philippines (; fil, Pilipinas, links=no), officially the Republic of the Philippines ( fil, Republika ng Pilipinas, links=no), * bik, Republika kan Filipinas * ceb, Republika sa Pilipinas * cbk, República de Filipinas * hil, Republ ...
hosts several nesting sites, including the island of
Boracay Boracay (; often locally shortened to Bora) is a resort island in the Western Visayas region of the Philippines, located off the northwest coast of Panay. It has a total land area of , under the jurisdiction of three barangays in Malay, Akla ...
and Punta Dumalag in
Davao City Davao City, officially the City of Davao ( ceb, Dakbayan sa Dabaw; ), is a first class highly urbanized city in the Davao Region, Philippines. The city has a total land area of , making it the largest city in the Philippines in terms of land ...
. Dahican Beach in
Mati City Mati, officially the City of Mati ( ceb, Dakbayan sa Mati; fil, Lungsod ng Mati), is a 5th class component city and capital of the province of Davao Oriental, Philippines. According to the 2020 census, it has a population of 147,547 people. ...
, Davao Oriental, hosts one of the essential hatcheries of its kind, along with
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 and most abundant of all sea turtles found in ...
s in the archipelagic country of the Philippines. A small group of islands in the southwest of the
archipelago An archipelago ( ), sometimes called an island group or island chain, is a chain, cluster, or collection of islands, or sometimes a sea containing a small number of scattered islands. Examples of archipelagos include: the Indonesian Arch ...
is named the " Turtle Islands" because two species of sea turtles nest there: the hawksbill and the green sea turtle. In January 2016, a juvenile was seen in
Gulf of Thailand The Gulf of Thailand, also known as the Gulf of Siam, is a shallow inlet in the southwestern South China Sea, bounded between the southwestern shores of the Indochinese Peninsula and the northern half of the Malay Peninsula. It is around in le ...
. A 2018 article by
The Straits Times ''The Straits Times'' is an English-language daily broadsheet newspaper based in Singapore and currently owned by SPH Media Trust (previously Singapore Press Holdings). ''The Sunday Times'' is its Sunday edition. The newspaper was establish ...
reported that around 120 hawksbill juvenile turtles recently hatched at
Pulau Satumu Pulau Satumu (Chinese: 沙都姆岛) is a small island to the south of the main Singapore Singapore (), officially the Republic of Singapore, is a sovereign island country and city-state in maritime Southeast Asia. It lies about one ...
,
Singapore Singapore (), officially the Republic of Singapore, is a sovereign island country and city-state in maritime Southeast Asia. It lies about one degree of latitude () north of the equator, off the southern tip of the Malay Peninsula, bor ...
. Commonly found in Singapore waters, hawksbill turtles have returned to areas such
East Coast Park East Coast Park is a beach and a park encompassing Marine Parade, Bedok and Tampines, along the southeastern coast of Singapore. It was opened in the 1970s, after the Singapore government had completed reclaiming land off the coast at Katong ...
and Palau Satumu to nest. In Hawaii, hawksbills mostly nest on the "main" islands of
Oahu Oahu () ( Hawaiian: ''Oʻahu'' ()), also known as "The Gathering Place", is the third-largest of the Hawaiian Islands. It is home to roughly one million people—over two-thirds of the population of the U.S. state of Hawaii. The island of O ...
,
Maui The island of Maui (; Hawaiian: ) is the second-largest of the islands of the state of Hawaii at 727.2 square miles (1,883 km2) and is the 17th largest island in the United States. Maui is the largest of Maui County's four islands, whic ...
,
Molokai Molokai , or Molokai (), is the fifth most populated of the eight major islands that make up the Hawaiian Islands archipelago in the middle of the Pacific Ocean. It is 38 by 10 miles (61 by 16 km) at its greatest length and width with a us ...
, and
Hawaii Hawaii ( ; haw, Hawaii or ) is a state in the Western United States, located in the Pacific Ocean about from the U.S. mainland. It is the only U.S. state outside North America, the only state that is an archipelago, and the only stat ...
. In
Australia Australia, officially the Commonwealth of Australia, is a sovereign country comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands. With an area of , Australia is the largest country by ...
, hawksbills are known to nest on Milman Island in the
Great Barrier Reef The Great Barrier Reef is the world's largest coral reef system composed of over 2,900 individual reefs and 900 islands stretching for over over an area of approximately . The reef is located in the Coral Sea, off the coast of Queensland, A ...
. Hawksbill sea turtles nest as far west as
Cousine Island Cousine Island is a small granitic island in the Seychelles west of Praslin Island. It is a combination luxury resort and since 1992 a nature preserve. History In 1992 the island was purchased and a conservation program was introduced to protec ...
in the
Seychelles Seychelles (, ; ), officially the Republic of Seychelles (french: link=no, République des Seychelles; Creole: ''La Repiblik Sesel''), is an archipelagic state consisting of 115 islands in the Indian Ocean. Its capital and largest city, ...
, where the species since 1994 is legally protected, and the population is showing some recovery. The Seychelles' inner islands and islets, such as
Aldabra Aldabra is the world's second-largest coral atoll, lying south-east of the continent of Africa. It is part of the Aldabra Group of islands in the Indian Ocean that are part of the Outer Islands of the Seychelles, with a distance of 1,120  ...
, are popular feeding grounds for immature hawksbills.


Eastern Pacific subpopulation

In the eastern Pacific, hawksbills are known to occur from the Baja Peninsula in
Mexico Mexico (Spanish language, Spanish: México), officially the United Mexican States, is a List of sovereign states, country in the southern portion of North America. It is borders of Mexico, bordered to the north by the United States; to the so ...
south along the coast to southern
Peru , image_flag = Flag of Peru.svg , image_coat = Escudo nacional del Perú.svg , other_symbol = Great Seal of the State , other_symbol_type = National seal , national_motto = "Firm and Happy f ...
. Nonetheless, as recently as 2007, the species had been considered extirpated mainly in the region. Important remnant nesting and foraging sites have since been discovered in Mexico,
El Salvador El Salvador (; , meaning " The Saviour"), officially the Republic of El Salvador ( es, República de El Salvador), is a country in Central America. It is bordered on the northeast by Honduras, on the northwest by Guatemala, and on the south ...
,
Nicaragua Nicaragua (; ), officially the Republic of Nicaragua (), is the largest country in Central America, bordered by Honduras to the north, the Caribbean to the east, Costa Rica to the south, and the Pacific Ocean to the west. Managua is the coun ...
, and
Ecuador Ecuador ( ; ; Quechua: ''Ikwayur''; Shuar: ''Ecuador'' or ''Ekuatur''), officially the Republic of Ecuador ( es, República del Ecuador, which literally translates as "Republic of the Equator"; Quechua: ''Ikwadur Ripuwlika''; Shuar: ' ...
, providing new research and conservation opportunities. In contrast to their traditional roles in other parts of the world, where hawksbills primarily inhabit coral reefs and rocky substrate areas, in the eastern Pacific, hawksbills tend to forage and nest principally in mangrove estuaries, such as those present in the Bahia de Jiquilisco (El Salvador),
Gulf of Fonseca The Gulf of Fonseca ( es, Golfo de Fonseca; ), a part of the Pacific Ocean, is a gulf in Central America, bordering El Salvador, Honduras, and Nicaragua. History Fonseca Bay was discovered for Europeans in 1522 by Gil González de Áv ...
(Nicaragua, El Salvador, and Honduras), Estero Padre Ramos (Nicaragua), and the Gulf of Guayaquil (Ecuador). Multi-national initiatives, such as th
Eastern Pacific Hawksbill Initiative
are currently pushing efforts to research and conserve the population, which remains poorly understood.


Habitat and feeding


Habitat

Adult hawksbill sea turtles are primarily found in tropical
coral reef A coral reef is an underwater ecosystem characterized by reef-building corals. Reefs are formed of Colony (biology), colonies of coral polyp (zoology), polyps held together by calcium carbonate. Most coral reefs are built from stony corals, wh ...
s. They are usually seen resting in caves and ledges in and around these reefs throughout the day. As a highly migratory species, they inhabit a wide range of habitats, from the open ocean to lagoons and even mangrove swamps in estuaries. Little is known about the habitat preferences of early life-stage ''E. imbricata''; like other young sea turtles, they are assumed to be completely pelagic, remaining at sea until they mature.


Feeding

While they are omnivorous,
sea sponge Sponges, the members of the phylum Porifera (; meaning 'pore bearer'), are a basal animal clade as a sister of the diploblasts. They are multicellular organisms that have bodies full of pores and channels allowing water to circulate through th ...
s are their principal food; they constitute 70–95% of the turtles' diets. However, like many
spongivore A spongivore is an animal anatomically and physiologically adapted to eating animals of the phylum Porifera, commonly called sea sponges, for the main component of its diet. As a result of their diet, spongivore animals like the hawksbill turtle ha ...
s, they feed only on select species, ignoring many others. Caribbean populations feed primarily on the orders Astrophorida,
Spirophorida ''Spirophorina'' is a suborder of sea sponges belonging to the class Demospongiae Demosponges (Demospongiae) are the most diverse class in the phylum Porifera. They include 76.2% of all species of sponges with nearly 8,800 species world ...
, and
Hadromerida Heteroscleromorpha is a subclass of demosponges within the phylum Porifera Sponges, the members of the phylum Porifera (; meaning 'pore bearer'), are a basal animal clade as a sister of the diploblasts. They are multicellular organisms th ...
in the class
Demospongiae Demosponges (Demospongiae) are the most diverse class in the phylum Porifera. They include 76.2% of all species of sponges with nearly 8,800 species worldwide (World Porifera Database). They are sponges with a soft body that covers a hard, ...
. Aside from sponges, hawksbills feed on
algae Algae (; singular alga ) is an informal term for a large and diverse group of photosynthetic eukaryotic organisms. It is a polyphyletic grouping that includes species from multiple distinct clades. Included organisms range from unicellular micr ...
, marine plants,
cnidaria Cnidaria () is a phylum under kingdom Animalia containing over 11,000 species of aquatic animals found both in freshwater and marine environments, predominantly the latter. Their distinguishing feature is cnidocytes, specialized cells that ...
ns,
comb jellies Ctenophora (; ctenophore ; ) comprise a phylum of marine invertebrates, commonly known as comb jellies, that inhabit sea waters worldwide. They are notable for the groups of cilia they use for swimming (commonly referred to as "combs"), and ...
and other
jellyfish Jellyfish and sea jellies are the informal common names given to the medusa-phase of certain gelatinous members of the subphylum Medusozoa, a major part of the phylum Cnidaria. Jellyfish are mainly free-swimming marine animals with umbre ...
,
sea anemone Sea anemones are a group of predatory marine invertebrates of the order Actiniaria. Because of their colourful appearance, they are named after the '' Anemone'', a terrestrial flowering plant. Sea anemones are classified in the phylum Cnidaria, ...
s,
mollusks Mollusca is the second-largest phylum of invertebrate animals after the Arthropoda, the members of which are known as molluscs or mollusks (). Around 85,000  extant species of molluscs are recognized. The number of fossil species is esti ...
,
fish Fish are Aquatic animal, aquatic, craniate, gill-bearing animals that lack Limb (anatomy), limbs with Digit (anatomy), digits. Included in this definition are the living hagfish, lampreys, and Chondrichthyes, cartilaginous and bony fish as we ...
and
crustaceans Crustaceans (Crustacea, ) form a large, diverse arthropod taxon which includes such animals as decapods, seed shrimp, branchiopods, fish lice, krill, remipedes, isopods, barnacles, copepods, amphipods and mantis shrimp. The crustacean g ...
. They also feed on the dangerous jellyfish-like
hydrozoa Hydrozoa (hydrozoans; ) are a taxonomic class of individually very small, predatory animals, some solitary and some colonial, most of which inhabit saline water. The colonies of the colonial species can be large, and in some cases the specialize ...
n, the
Portuguese man o' war The Portuguese man o' war (''Physalia physalis''), also known as the man-of-war, is a marine hydrozoan found in the Atlantic Ocean and the Indian Ocean. It is considered to be the same species as the Pacific man o' war or blue bottle, which is ...
(''Physalia physalis''). Hawksbills close their unprotected eyes when they feed on these cnidarians. The man o' war's stinging cells cannot penetrate the turtles' armored heads. Hawksbills are highly resilient and resistant to their prey. Some of the sponges they eat, such as ''
Aaptos aaptos ''Aaptos aaptos'' is a species of sea sponge belonging to the family Suberitidae. This particular species is known to contain adrenoreceptor-blocking compounds. While it is highly toxic to fish, it is known to be preyed upon by the hawksbill t ...
'', '' Chondrilla nucula'', '' Tethya actinia'', ''
Spheciospongia vesparium ''Spheciospongia vesparium'', commonly known as the loggerhead sponge, is a species of sea sponge belonging to the family Clionaidae. While it is highly toxic to many fish, this sponge is eaten by certain angelfish and is known to form part of t ...
'', and ''
Suberites domuncula ''Suberites domuncula'' is a species of sea sponge belonging to the family Suberitidae. This species contains suberitine, a neurotoxin that can cause fatal hemolytic hemorrhaging in various animals. While it is highly toxic to fish, it is kno ...
'', are highly (often lethally)
toxic Toxicity is the degree to which a chemical substance or a particular mixture of substances can damage an organism. Toxicity can refer to the effect on a whole organism, such as an animal, bacterium, or plant, as well as the effect on a sub ...
to other organisms. In addition, hawksbills choose sponge species with significant numbers of
siliceous Silicon dioxide, also known as silica, is an oxide of silicon with the chemical formula , most commonly found in nature as quartz and in various living organisms. In many parts of the world, silica is the major constituent of sand. Silica is one ...
spicules, such as '' Ancorina'', ''
Geodia ''Geodia'' is a genus of sea sponge belonging to the family Geodiidae. It is the type genus of its taxonomic family. This genus is characterized by a high density of siliceous spicules. Members of this genus are known to be eaten by hawksbill t ...
'' ('' G. gibberosa''), ''
Ecionemia ''Ecionemia'' is a genus of sea sponges belonging to the family Ancorinidae. This genus is characterized by a high density of siliceous spicules. Members of this genus are known to be eaten by hawksbill turtle The hawksbill sea turtle ('' ...
'', and '' Placospongia''.


Life history

Less is known about the life history of hawksbills by comparison to several other sea turtle species. Their life history may be divided into three phases, the: (i) early life history phase from approximately 4–30 cm straight carapace length, (ii) benthic phase when the immature turtles recruit to foraging areas, and (iii) reproductive phase, when individuals reach sexual maturity and begin periodically migrating to breeding grounds. The early life history phase is not as geographically resolved as other sea turtle species. This phase appears to vary across ocean regions and may occur in both pelagic and nearshore waters, possibly lasting from 0–4 years of age. One study from the central Pacific Ocean population used bomb radiocarbon (14C) dating and von Bertalanffy growth models to estimate hawksbills reach sexual maturity at ~ 72 cm and 29 years of age (range 23–36 years). Hawksbills show a degree of fidelity after recruiting to the benthic phase however, the movement to other similar habitats is possible.


Breeding

Hawksbills mate biannually in secluded lagoons off their nesting beaches in remote islands throughout their range. The most significant nesting beaches are in Mexico, the Seychelles, Indonesia, Sri Lanka, and Australia. The mating season for Atlantic hawksbills usually spans April to November. Indian Ocean populations, such as the
Seychelles Seychelles (, ; ), officially the Republic of Seychelles (french: link=no, République des Seychelles; Creole: ''La Repiblik Sesel''), is an archipelagic state consisting of 115 islands in the Indian Ocean. Its capital and largest city, ...
hawksbill population, mate from September to February. After mating, females drag their heavy bodies high onto the beach during the night. They clear an area of debris and dig a nesting hole using their rear flippers, then lay
clutch A clutch is a mechanical device that engages and disengages power transmission, especially from a drive shaft to a driven shaft. In the simplest application, clutches connect and disconnect two rotating shafts (drive shafts or line shafts). ...
es of eggs and cover them with sand.
Caribbean The Caribbean (, ) ( es, El Caribe; french: la Caraïbe; ht, Karayib; nl, De Caraïben) is a region of the Americas that consists of the Caribbean Sea, its islands (some surrounded by the Caribbean Sea and some bordering both the Caribbean ...
and
Florida Florida is a state located in the Southeastern region of the United States. Florida is bordered to the west by the Gulf of Mexico, to the northwest by Alabama, to the north by Georgia, to the east by the Bahamas and Atlantic Ocean, and ...
nests of ''E. imbricata'' typically contain around 140 eggs. After the hours-long process, the female returns to the sea. Their nests can be found throughout beaches in about 60 countries. Hatchlings, usually weighing less than , hatch at night after around two months. These newly emergent
hatchling In oviparous biology, a hatchling is a newly hatched fish, amphibian, reptile, or bird. A group of mammals called monotremes lay eggs, and their young are hatchlings as well. Fish Fish hatchlings generally do not receive parental care, similar to ...
s are dark-colored, with heart-shaped carapaces measuring approximately long. They instinctively crawl into the sea, attracted by the moon's reflection on the water (disrupted by light sources such as street lamps and lights). While they emerge under the cover of darkness, hatchlings that do not reach the water by daybreak are preyed upon by
shorebirds 245px, A flock of Dunlins and Red knots">Red_knot.html" ;"title="Dunlins and Red knot">Dunlins and Red knots Waders or shorebirds are birds of the order Charadriiformes commonly found wikt:wade#Etymology 1, wading along shorelines and mudflat ...
, shore crabs, and other predators.


Maturity

Hawksbills evidently reach maturity after 20 years. Their lifespan is unknown. Like other sea turtles, hawksbills are solitary for most of their lives; they meet only to mate. They are highly migratory. Because of their tough carapaces, adults' only predators are
shark Sharks are a group of elasmobranch fish characterized by a cartilaginous skeleton, five to seven gill slits on the sides of the head, and pectoral fins that are not fused to the head. Modern sharks are classified within the clade Selachi ...
s, estuarine crocodiles,
octopus An octopus ( : octopuses or octopodes, see below for variants) is a soft-bodied, eight- limbed mollusc of the order Octopoda (, ). The order consists of some 300 species and is grouped within the class Cephalopoda with squids, cuttlefish, ...
es, and some
pelagic fish Pelagic fish live in the pelagic zone of ocean or lake waters—being neither close to the bottom nor near the shore—in contrast with demersal fish that do live on or near the bottom, and reef fish that are associated with coral re ...
species. A series of biotic and abiotic cues, such as individual genetics, foraging quantity and quality, or population density, may trigger the maturation of the reproductive organs and the production of gametes and thus determine sexual maturity. Like many reptiles, all marine turtles of the same aggregation are highly unlikely to reach sexual maturity at the same size and thus age. Age at maturity has been estimated to occur between 10 and 25 years of age for Caribbean hawksbills. Turtles nesting in the Indo-Pacific region may reach maturity at a minimum of 30 to 35 years.


Evolutionary history

Within the sea turtles, ''E. imbricata'' has several unique
anatomical Anatomy () is the branch of biology concerned with the study of the structure of organisms and their parts. Anatomy is a branch of natural science that deals with the structural organization of living things. It is an old science, having it ...
and
ecological Ecology () is the study of the relationships between living organisms, including humans, and their physical environment. Ecology considers organisms at the individual, population, community, ecosystem, and biosphere level. Ecology overlaps wi ...
traits. It is the only primarily spongivorous reptile. Because of this, its evolutionary position is somewhat unclear. Molecular analyses support ''Eretmochelys'' placement within the taxonomic tribe Carettini, including the
carnivorous A carnivore , or meat-eater (Latin, ''caro'', genitive ''carnis'', meaning meat or "flesh" and ''vorare'' meaning "to devour"), is an animal or plant whose food and energy requirements derive from animal tissues (mainly muscle, fat and other ...
loggerhead Loggerhead or Loggerheads may refer to: Places * Loggerheads, Denbighshire, a village in Denbighshire, Wales * Loggerheads, Staffordshire, a small village in north Staffordshire, England * Loggerhead Key, the largest islet in the Dry Tortugas, F ...
and ridley sea turtles, rather than in the tribe Chelonini, which includes the
herbivorous A herbivore is an animal anatomically and physiologically adapted to eating plant material, for example foliage or marine algae, for the main component of its diet. As a result of their plant diet, herbivorous animals typically have mouthpar ...
green turtle The green sea turtle (''Chelonia mydas''), also known as the green turtle, black (sea) turtle or Pacific green turtle, is a species of large sea turtle of the family Cheloniidae. It is the only species in the genus ''Chelonia''. Its range exten ...
. The hawksbill probably evolved from carnivorous ancestors.


Exploitation by humans

Throughout the world, hawksbill turtles have been hunted by humans, though it is illegal to capture, kill, and trade hawksbills in many countries today. In some parts of the world, hawksbill turtles and their eggs continue to be exploited as food. As far back as the fifth century BCE, sea turtles, including the hawksbill, were eaten as delicacies in
China China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's List of countries and dependencies by population, most populous country, with a Population of China, population exceeding 1.4 billion, slig ...
. Beyond direct consumption for food, many cultures have also exploited hawksbill populations for their ornate carapace shells, known variously as tortoiseshell, turtle shell, and ''bekko''. STRP Hawksbill Sea Turtle In China, where it was known as ''tai mei'', the hawksbill is called the "tortoise-shell turtle", named primarily for its shell, which was used to make and decorate a variety of small items, as it was in the West. Along the south coast of Java, stuffed hawksbill turtles are sold in souvenir shops, though numbers have decreased in the last two decades. In
Japan Japan ( ja, 日本, or , and formally , ''Nihonkoku'') is an island country in East Asia. It is situated in the northwest Pacific Ocean, and is bordered on the west by the Sea of Japan, while extending from the Sea of Okhotsk in the n ...
, the turtles are harvested for their shell
scute A scute or scutum (Latin: ''scutum''; plural: ''scuta'' "shield") is a bony external plate or scale overlaid with horn, as on the shell of a turtle, the skin of crocodilians, and the feet of birds. The term is also used to describe the anterior po ...
s, called ''bekko'' in Japanese. ''Bekko'' is used in various personal implements, such as eyeglass frames and the ''
shamisen The , also known as the or (all meaning "three strings"), is a three-stringed traditional Japanese musical instrument derived from the Chinese instrument . It is played with a plectrum called a bachi. The Japanese pronunciation is usua ...
'' (Japanese traditional three-stringed instrument) picks. In 1994, Japan stopped importing hawksbill shells from other nations. Prior to this, the Japanese hawksbill shell trade was around of raw shells per year. In Europe, hawksbill sea turtle shells were harvested by the
ancient Greek Ancient Greek includes the forms of the Greek language used in ancient Greece and the ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (), Dark Ages (), the Archaic pe ...
s and
ancient Roman In modern historiography, ancient Rome refers to Roman civilisation from the founding of the city of Rome in the 8th century BC to the collapse of the Western Roman Empire in the 5th century AD. It encompasses the Roman Kingdom (753–50 ...
s for jewellery, such as combs, brushes, and rings. Recently, processed shells were regularly available in large amounts in countries including the
Dominican Republic The Dominican Republic ( ; es, República Dominicana, ) is a country located on the island of Hispaniola in the Greater Antilles archipelago of the Caribbean region. It occupies the eastern five-eighths of the island, which it shares with ...
and
Colombia Colombia (, ; ), officially the Republic of Colombia, is a country in South America with insular regions in North America—near Nicaragua's Caribbean coast—as well as in the Pacific Ocean. The Colombian mainland is bordered by the ...
. Global estimates of the historical exploitation of hawksbills have received recent attention. From 1950-1992, one pioneering study estimated that as many as 1.37 million adult hawksbills were killed in the international tortoiseshell trade alone. With the aid of substantial additional trade data, including official trade records from the imperial Japanese archives, the international trade of tortoiseshell was recently updated to have killed approximately 8.98 million hawksbills (range 4.64 to 9.83 million) from 1844-1992. Most of the trade occurred in the Pacific Ocean basin, and the countries of origin and trade routes bore similarity to what is known of
illegal, unreported and unregulated fishing Illegal, unreported and unregulated fishing (IUU) is an issue around the world. Fishing industry observers believe IUU occurs in most fisheries, and accounts for up to 30% of total catches in some important fisheries. Illegal fishing takes pl ...
(IUU fishing).


Conservation

Consensus has determined sea turtles, including ''E. imbricata'' to be at least threatened, because of their slow growth and maturity and low reproductive rates. Humans have killed many adult turtles, both accidentally and deliberately. Their existence is threatened due to pollution and loss of nesting areas because of coastal development. Biologists estimate that the hawksbill population has declined 80 percent in the past 100–135 years. Human and animal encroachment threatens nesting sites, and small mammals dig up the eggs to eat. In the
US Virgin Islands The United States Virgin Islands,. Also called the ''American Virgin Islands'' and the ''U.S. Virgin Islands''. officially the Virgin Islands of the United States, are a group of Caribbean islands and an unincorporated and organized territory ...
,
mongoose A mongoose is a small terrestrial carnivorous mammal belonging to the family Herpestidae. This family is currently split into two subfamilies, the Herpestinae and the Mungotinae. The Herpestinae comprises 23 living species that are native to so ...
s raid hawksbill nests (along with other sea turtles, such as ''
Dermochelys coriacea The leatherback sea turtle (''Dermochelys coriacea''), sometimes called the lute turtle or leathery turtle or simply the luth, is the largest of all living turtles and the heaviest non-crocodilian reptile, reaching lengths of up to and weights ...
'') right after they are laid. In 1982, the
IUCN Red List of Threatened Species The International Union for Conservation of Nature (IUCN) Red List of Threatened Species, also known as the IUCN Red List or Red Data Book, founded in 1964, is the world's most comprehensive inventory of the global conservation status of biologi ...
first listed ''E. imbricata'' as
endangered An endangered species is a species that is very likely to become extinct in the near future, either worldwide or in a particular political jurisdiction. Endangered species may be at risk due to factors such as habitat loss, poaching and in ...
. This endangered status continued through several reassessments in 1986, 1988, 1990, and 1994 until it was upgraded in status to '' critically endangered'' in 1996. Two petitions challenged its status as an
endangered species An endangered species is a species that is very likely to become extinct in the near future, either worldwide or in a particular political jurisdiction. Endangered species may be at risk due to factors such as habitat loss, poaching and inv ...
prior to this, claiming the turtle (along with three other species) had several significant stable populations worldwide. These petitions were rejected based on their data analysis submitted by the Marine Turtle Specialist Group (MTSG). The MTSG data showed the worldwide hawksbill sea turtle population had declined by 80% in the three most recent generations, and no significant population increase had occurred as of 1996. CR A2 status was denied, however, because the IUCN did not find sufficient data to show the population likely to decrease by a further 80%. The species (along with the entire Cheloniidae family) has been listed in Appendix I of the
Convention on International Trade in Endangered Species CITES (shorter name for the Convention on International Trade in Endangered Species of Wild Fauna and Flora, also known as the Washington Convention) is a multilateral treaty to protect endangered plants and animals from the threats of intern ...
. This means commercial international trade (including in parts and derivatives) is prohibited and non-commercial international trade is regulated. The
United States Fish and Wildlife Service The United States Fish and Wildlife Service (USFWS or FWS) is an agency within the United States Department of the Interior dedicated to the management of fish, wildlife, and natural habitats. The mission of the agency is "working with othe ...
and
National Marine Fisheries Service 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 stew ...
have classified hawksbills as endangered under the
Endangered Species Act The Endangered Species Act of 1973 (ESA or "The Act"; 16 U.S.C. § 1531 et seq.) is the primary law in the United States for protecting imperiled species. Designed to protect critically imperiled species from extinction as a "consequence of ec ...
since 1970. The US government established several recovery plans for protecting ''E. imbricata''. The
Zoological Society of London The Zoological Society of London (ZSL) is a charity devoted to the worldwide conservation of animals and their habitats. It was founded in 1826. Since 1828, it has maintained the London Zoo, and since 1931 Whipsnade Park. History On 29 ...
has inscribed the reptile as an EDGE species, meaning that it is both endangered and highly genetically distinct, and therefore of particular concern for conservation efforts. The
World Wildlife Fund The World Wide Fund for Nature Inc. (WWF) is an international non-governmental organization founded in 1961 that works in the field of wilderness preservation and the reduction of human impact on the environment. It was formerly named the W ...
Australia (WWF-Australia) has several ongoing projects aiming at protecting the reptile. On
Rosemary Island Rosemary Island is an island in the Dampier Archipelago in the Pilbara region of Western Australia. With Enderby Island it forms Class A Nature Reserve 36915, part of a proposed national park. During World War II an airstrip was established a ...
, an island in the
Dampier Archipelago The Dampier Archipelago is a group of 42 islands near the town of Dampier in the Pilbara, Western Australia. The archipelago is also made up of reefs, shoals, channels and straits and is the traditional home of five Aboriginal language group ...
off the
Pilbara The Pilbara () is a large, dry, thinly populated region in the north of Western Australia. It is known for its Aboriginal peoples; its ancient landscapes; the red earth; and its vast mineral deposits, in particular iron ore. It is also a g ...
coast of
Western Australia Western Australia (commonly abbreviated as WA) is a state of Australia occupying the western percent of the land area of Australia excluding external territories. It is bounded by the Indian Ocean to the north and west, the Southern Ocean to t ...
, volunteers have been monitoring hawksbill turtles since 1986. In November 2020, a 60-year old turtle first tagged in November 1990 and again in 2011 returned to the same location.


References


External links

*
US National Marine Fisheries Service hawksbill sea turtle page

Seaturtle.org
Home to sea turtle conservation efforts such as the Marine Turtle Research Group and publisher of the ''Marine Turtle Newsletter''.
Hawksbill turtle in Bocas Del Toro

Australian Government Department of the Environment
* {{Authority control
hawksbill sea turtle The hawksbill sea turtle (''Eretmochelys imbricata'') 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 large ...
hawksbill sea-turtle Pantropical fauna Critically endangered animals ESA endangered species
hawksbill sea turtle The hawksbill sea turtle (''Eretmochelys imbricata'') 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 large ...
Taxa named by Carl Linnaeus