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Threatened Threatened species are any species (including animals, plants and fungi) which are vulnerable to endangerment in the near future. Species that are threatened are sometimes characterised by the population dynamics measure of ''critical depensat ...

rays Ray may refer to: Fish * Ray (fish), any cartilaginous fish of the superorder Batoidea * Ray (fish fin anatomy), a bony or horny spine on a fin Science and mathematics * Ray (geometry), half of a line proceeding from an initial point * Ray (gra ...

are those vulnerable to

endangerment Endangerment is a type of crime involving conduct that is wrongful and reckless or wanton, and likely to produce death or grievous bodily harm to another person. There are several kinds of endangerment, each of which is a criminal act that can b ...

(

extinction Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and ...

) in the near future. The International Union for Conservation of Nature (

IUCN 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 natu ...

) ranks threatened species in three categories: ::

Vulnerable species A vulnerable species is a species which has been Conservation status, categorized by the International Union for Conservation of Nature as being threatened species, threatened with extinction unless the circumstances that are threatened species, ...

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 ...

:: Critically endangered species The term ''threatened'' strictly refers to these three categories (critically endangered, endangered and vulnerable), while ''vulnerable'' is used to refer to the least at risk of these categories. The terms can be used somewhat interchangeably, as all ''vulnerable'' species are threatened, all ''endangered'' species are vulnerable and threatened, and all ''critically endangered'' species are endangered, vulnerable and threatened. Threatened species are also referred to as a

red-listed 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 ...

species, as they are listed in 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 ...

. Together

and

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 Selachimo ...

s make up the

class Class or The Class may refer to: Common uses not otherwise categorized * Class (biology), a taxonomic rank * Class (knowledge representation), a collection of individuals or objects * Class (philosophy), an analytical concept used differentl ...

of modern

cartilaginous fishes Chondrichthyes (; ) is a class that contains the cartilaginous fishes that have skeletons primarily composed of cartilage. They can be contrasted with the Osteichthyes or ''bony fishes'', which have skeletons primarily composed of bone tissue ...

. Modern fish are either cartilaginous or bony. Cartilaginous fishes have skeletons made of

cartilage Cartilage is a resilient and smooth type of connective tissue. In tetrapods, it covers and protects the ends of long bones at the joints as articular cartilage, and is a structural component of many body parts including the rib cage, the neck an ...

while

bony fishes Osteichthyes (), popularly referred to as the bony fish, is a diverse superclass of fish that have skeletons primarily composed of bone tissue. They can be contrasted with the Chondrichthyes, which have skeletons primarily composed of cartilage ...

have skeletons made of

bone A bone is a Stiffness, rigid Organ (biology), organ that constitutes part of the skeleton in most vertebrate animals. Bones protect the various other organs of the body, produce red blood cell, red and white blood cells, store minerals, provid ...

. Because rays and sharks are closely related, they are often studied together. In 2010 a global IUCN study of vertebrates found that of 1,044 cartilaginous (ray and shark) species examined, 345 or 33% were threatened with extinction. There are four

orders Order, ORDER or Orders may refer to: * Categorization, the process in which ideas and objects are recognized, differentiated, and understood * Heterarchy, a system of organization wherein the elements have the potential to be ranked a number of d ...

of rays:

stingrays Stingrays are a group of sea rays, which are cartilaginous fish related to sharks. They are classified in the suborder Myliobatoidei of the order Myliobatiformes and consist of eight families: Hexatrygonidae (sixgill stingray), Plesiobatidae (d ...

, skates,

electric rays The electric rays are a group of rays, flattened cartilaginous fish with enlarged pectoral fins, composing the order Torpediniformes . They are known for being capable of producing an electric discharge, ranging from 8 to 220 volts, depending ...

and

sawfishes Sawfish, also known as carpenter sharks, are a family of rays characterized by a long, narrow, flattened rostrum, or nose extension, lined with sharp transverse teeth, arranged in a way that resembles a saw. They are among the largest fish wit ...

. Like sharks, rays are relatively long living and thrive in stable populations. They are

K-strategists In ecology, ''r''/''K'' selection theory relates to the selection of combinations of traits in an organism that trade off between quantity and quality of offspring. The focus on either an increased quantity of offspring at the expense of individ ...

which grow slowly, mature late sexually and produce few offspring. They cannot recover as rapidly as many faster growing fish can if their populations are depleted. As with sharks, rays are increasingly becoming vulnerable because of commercial and recreational fishing pressures, the impact of non-ray fisheries on the seabed and ray prey species, and other habitat alterations such as damage and loss from coastal development and

marine pollution Marine pollution occurs when substances used or spread by humans, such as industrial waste, industrial, agricultural pollution, agricultural and municipal solid waste, residential waste, particle (ecology), particles, noise, excess carbon dioxid ...

. Most particularly, the continuing decline of threatened rays and sharks is the consequence of unregulated fishing, as illustrated by a recent international survey which listed only 38 species of skates and rays still subsisting in the highly impacted Mediterranean Sea.

Manta ray Manta rays are large rays belonging to the genus ''Mobula'' (formerly its own genus ''Manta''). The larger species, '' M. birostris'', reaches in width, while the smaller, '' M. alfredi'', reaches . Both have triangular Pectoral fin#AnchPect ...

s are largest rays in the world, with wingspans reaching 7 metres.Glider of the sea threatened by 'traditional' medicine
''New Scientist'', 25 March 2013. They have one of the highest brain-to-body mass ratios of all fish. Manta populations suffer when they are caught as

bycatch Bycatch (or by-catch), in the fishing industry, is a fish or other marine species that is caught unintentionally while fishing for specific species or sizes of wildlife. Bycatch is either the wrong species, the wrong sex, or is undersized or juve ...

by fishermen fishing for other species, but fisheries which target manta rays are even more harmful. Manta rays use their gills to filter plankton from the sea. Demand for their dried

gill raker Gill rakers in fish are bony or cartilaginous processes that project from the branchial arch (gill arch) and are involved with suspension feeding tiny prey. They are not to be confused with the gill filaments that compose the fleshy part of the ...

cartilaginous Cartilage is a resilient and smooth type of connective tissue. In tetrapods, it covers and protects the ends of long bones at the joints as articular cartilage, and is a structural component of many body parts including the rib cage, the neck and ...

structures protecting the gills, has been growing in

traditional Chinese medicine Traditional Chinese medicine (TCM) is an alternative medical practice drawn from traditional medicine in China. It has been described as "fraught with pseudoscience", with the majority of its treatments having no logical mechanism of action ...

practices. The market is "bogus" since dried manta gills have never been used historically in Chinese medicine, and there is no evidence that the gills have any medicinal value. The flesh is edible and is consumed in some countries, but is tough and unattractive compared to other fish. To fill the growing demand in Asia for gill rakers, targeted fisheries have developed in other parts of the world, including Sri Lanka, Indonesia, West Africa and Central and South America. Each year, thousands of manta rays, primarily the

giant manta ray The giant oceanic manta ray, giant manta ray, or oceanic manta ray (''Mobula birostris'') is a species of ray in the family Mobulidae, and the largest type of ray in the world. It is circumglobal and is typically found in tropical and subtropica ...

, are being caught and killed purely for their gill rakers. A fisheries study in Sri Lanka estimated that over a thousand of these were being sold in the country's fish markets each year. In 2011, manta rays became strictly protected in international waters thanks to their recent inclusion in the Convention on Migratory Species of Wild Animals. The CMS is an international treaty organization concerned with conserving migratory species and habitats on a global scale. Although individual nations were already protecting manta rays, the fish often migrate through unregulated waters, putting them at increased risk from overfishing. In 2013, the Convention on International Trade in Endangered Species (

CITES 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 interna ...

) listed both species of manta rays as

CITES Appendix II 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 interna ...

species. This means that the international trade of manta rays will now be monitored and regulated.Proposal 46: Genus ''Manta''
''CITES'', Sixteenth meeting of the Conference of the Parties Bangkok (Thailand), 3–14 March 2013.CITES conference takes decisive action to halt decline of tropical timber, sharks, manta rays and a wide range of other plants and animals
/ref>

Sawfish Sawfish, also known as carpenter sharks, are a family of rays characterized by a long, narrow, flattened rostrum, or nose extension, lined with sharp transverse teeth, arranged in a way that resembles a saw. They are among the largest fish wi ...

are a less well known family of rays which have a long

rostrum Rostrum may refer to: * Any kind of a platform for a speaker: **dais **pulpit * Rostrum (anatomy), a beak, or anatomical structure resembling a beak, as in the mouthparts of many sucking insects * Rostrum (ship), a form of bow on naval ships * Ros ...

resembling a saw. Some

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 appropriate s ...

can reach in length. All species of sawfish are either

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 inva ...

or critically endangered as a result of

habitat destruction Habitat destruction (also termed habitat loss and habitat reduction) is the process by which a natural habitat becomes incapable of supporting its native species. The organisms that previously inhabited the site are displaced or dead, thereby ...

and

overfishing Overfishing is the removal of a species of fish (i.e. fishing) from a body of water at a rate greater than that the species can replenish its population naturally (i.e. the overexploitation of the fishery's existing fish stock), resulting in th ...

. Their young stay close to shore, and are particularly affected by coastal developments.Sawfish Is First Sea Fish on U.S. Endangered List
''National Geographic News'', 4 June 2003. Because their rostrum is easily entangled, sawfishes can easily become

in fishing nets. They are also exploited for the novelty value of their rostrum, their fins are eaten as a delicacy in China, and their liver oil used as a food supplement. While arguing for a global ban on international commerce in 2007, a representative from the National Museums of

Kenya ) , national_anthem = "Ee Mungu Nguvu Yetu"() , image_map = , map_caption = , image_map2 = , capital = Nairobi , coordinates = , largest_city = Nairobi , ...

stated, "Only the meat is consumed locally; and artisanal fishermen can retire after catching one sawfish due to the high value of a single rostrum, up to $1,450." In 2013

uplisted the

largetooth sawfish The largetooth sawfish (''Pristis pristis'', syn. ''P. microdon'' and ''P. perotteti'') is a species of sawfish, family Pristidae. It is found worldwide in tropical and subtropical coastal regions, but also enters freshwater. It has declined dra ...

to Appendix I. This is CITES highest protection level, and means that all international trade of the species is banned. According to a 2021 study published in the journal ''

Nature Nature, in the broadest sense, is the physics, physical world or universe. "Nature" can refer to the phenomenon, phenomena of the physical world, and also to life in general. The study of nature is a large, if not the only, part of science. ...

'', relative

fishing pressure Overfishing is the removal of a species of fish (i.e. fishing) from a body of water at a rate greater than that the species can replenish its population naturally (i.e. the overexploitation of the fishery's existing fish stock), resulting in the ...

in the oceans has increased by a factor of 18 since 1970. This overfishing has resulted in the number of oceanic sharks and rays declining globally by 71%, and has increased the global extinction risk to the point where three-quarters of these species are now threatened with extinction. Precautionary science-based catch limits and strict prohibitions are now needed urgently if population collapse is to be avoided, if the disruption of ecological functions is to be averted, and if a start is to be made on rebuilding global fisheries.

List

References

External links

Protecting the fragile manta rays of the Maldives
''BBC'', 5 March 2012. {{threatened species Rays,threatened Rays,threatened Rays,threatened

Rays Ray may refer to: Fish * Ray (fish), any cartilaginous fish of the superorder Batoidea * Ray (fish fin anatomy), a bony or horny spine on a fin Science and mathematics * Ray (geometry), half of a line proceeding from an initial point * Ray (gra ...

List

See also

References

Further reading

External links