Red stingray
Encyclopedia
The red stingray is a species
of stingray
in the family
Dasyatidae, found in the northwestern Pacific Ocean
off Japan
, Korea
, and China
, and possibly elsewhere. It primarily inhabits shallow, sandy habitat
s close to shore, and has been known to enter brackish water
. The red stingray has a diamond-shaped pectoral fin disc and gains its common name
from its bright orange-red underside; there may also be patches of orange at various spots on its upper surface. Most individuals are no more than 1 m (3.3 ft) long.
Feeding mainly on crustacean
s and bony fishes, the red stingray plays a key ecological role as an apex predator
in its environment. Reproduction is aplacental viviparous, with females giving birth to 1 or up to 10 pups at a time. The red stingray is valued as food in Japan; large numbers are caught as bycatch
and brought to market, which has seemingly led to a population decline in this unprolific species. As a result, the International Union for Conservation of Nature (IUCN) has assessed it as Near Threatened
.
and Friedrich Henle
in their 1841 Systematische Beschreibung der Plagiostomen under the name Trygon akajei, based on an earlier account of "Pastinaca akajei" by Heinrich Bürger
. Subsequent authors have placed the genus Trygon in synonymy
with Dasyatis. A lectotype
for this species was designated by Marinus Boeseman in 1947. Other common name
s for the red stingray include brown stingray, estuary stingaree, Japanese red stingray, Japanese stingray, red skate, whip ray, whip stingray, and yellow stingray.
; it is found throughout Japan
ese coastal waters from Hokkaidō
to Okinawa, and also occurs off Korea
, mainland China
and Taiwan
. This species has been reported from as far as Thailand
, the Philippines
, Fiji
, and Tuvalu
. However, whether these records truly represent D. akajei has yet to be determined. The red stingray is commonly encountered in sandy areas close to shore and in bay
s at a depth of 10 m (32.8 ft) or more, but also inhabits muddy flats, coral reef
s, and estuaries.
s that are almost twice as large. There is a thick flap of skin between the large nares. The teeth are arranged with a quincunx
pattern into a pavement-like surface. Females and juveniles have blunt teeth, while adult males have pointed, recurved teeth. There is a row of 3 papilla
e across the floor of the mouth, sometimes with up to 2 pairs of accessory papillae alongside.
The tail is whip-like and measures 1–1.5 times as long as the disc is wide. A long, serrated spine originates in the first third of the tail, and is followed by a low dorsal keel and a ventral fin fold. Young rays have smooth skin, while adults have a patch of small dermal denticles between and behind the eyes, and a row of thorns along the midline of the back. There are 1–6 tubercles in front of the tail spine, and numerous small denticles behind. This species is plain brown above, often with yellow or orange coloring before the eyes, behind the spiracles, around the disc margin, and laterally on the tail in front of the spine. The tail darkens to nearly black towards the tip and on the ventral fin fold. The underside is white with bright orange-red patches. The Mekong freshwater stingray
(D. laosensis) is also characterized by orange ventral coloration and has some similar meristic counts to this species, but differs in disc shape, denticle coverage, and dorsal coloration.
in nearshore demersal food web
s, the red stingray plays a significant ecological role. Crustacean
s are the most important component of its diet, followed by small bony fishes and then annelid worms, while molluscs are seldom consumed. In Tokyo Bay
, important crustacean prey species are Crangon affinis for males, Oratosquilla ijimai for females, and Anisomysis ijimai for juveniles; the most important fish prey species is Sardinops melanostictus, followed by Conger myriaster
. Like other stingrays, the red stingray is aplacental viviparous. During courtship, the male follows the female and bites at her pectoral fin disc, using his pointed teeth to gain a grip for copulation. The litter size has been variously reported as only 1 or up to 10. Males mature sexually
at a disc width of 35–40 cm (13.8–15.7 in), and females at a disc width of 50–55 cm (19.7–21.7 in).
Known parasites of the red stingray include the tapeworms Acanthobothrium macrocephalum, Rhodobothrium pulvinatum, and Tetragonocephalum akajeinensis, the monogenea
ns Dendromonocotyle akajeii and Heterocotyle chinensis, the leech
Pterobdella amara, the nematode
s Porrocaecum laymani and Terranova amoyensis, the copepod
Trebius akajeii, and the pranzia larva
e of the isopod Gnathia capillata.
ous tail spine of the red stingray is potentially injurious to humans. The Ainu
once used the dried tail spine, with the toxic sheath intact, as a weapon. This species is an incidental catch
of commercial fisheries
targeting flounder
and other bottom-dwelling fishes, using bottom trawls, gillnet
s, set nets
, and line gear. It is valued as food in Japan, especially in the Tokyo Bay area where it is consumed in autumn and winter; it may be prepared hard boiled, with miso soup
, or as kamaboko
. However, the small size of the red stingray limits its economic importance. Annual catches reported by Japanese fisheries have steadily declined from 20,000 tons in 1950 to varying between 3,959 and 5,388 tons from 1997 to 2004. Such apparent depletion, coupled with continuing heavy fishing pressure and a slow reproductive rate, have led the International Union for Conservation of Nature (IUCN) to assess this species as Near Threatened
.
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
of stingray
Myliobatiformes
Myliobatiformes is one of the four orders of batoids, cartilaginous fishes related to sharks. They were formerly included in the order Rajiformes, but more recent phylogenetic studies have shown that the myliobatiforms are a monophyletic group, and that its more derived members evolved their...
in the family
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
Dasyatidae, found in the northwestern Pacific Ocean
Pacific Ocean
The Pacific Ocean is the largest of the Earth's oceanic divisions. It extends from the Arctic in the north to the Southern Ocean in the south, bounded by Asia and Australia in the west, and the Americas in the east.At 165.2 million square kilometres in area, this largest division of the World...
off Japan
Japan
Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...
, Korea
Korea
Korea ) is an East Asian geographic region that is currently divided into two separate sovereign states — North Korea and South Korea. Located on the Korean Peninsula, Korea is bordered by the People's Republic of China to the northwest, Russia to the northeast, and is separated from Japan to the...
, and China
China
Chinese civilization may refer to:* China for more general discussion of the country.* Chinese culture* Greater China, the transnational community of ethnic Chinese.* History of China* Sinosphere, the area historically affected by Chinese culture...
, and possibly elsewhere. It primarily inhabits shallow, sandy habitat
Habitat
* Habitat , a place where a species lives and grows*Human habitat, a place where humans live, work or play** Space habitat, a space station intended as a permanent settlement...
s close to shore, and has been known to enter brackish water
Brackish water
Brackish water is water that has more salinity than fresh water, but not as much as seawater. It may result from mixing of seawater with fresh water, as in estuaries, or it may occur in brackish fossil aquifers. The word comes from the Middle Dutch root "brak," meaning "salty"...
. The red stingray has a diamond-shaped pectoral fin disc and gains its common name
Common name
A common name of a taxon or organism is a name in general use within a community; it is often contrasted with the scientific name for the same organism...
from its bright orange-red underside; there may also be patches of orange at various spots on its upper surface. Most individuals are no more than 1 m (3.3 ft) long.
Feeding mainly on crustacean
Crustacean
Crustaceans form a very large group of arthropods, usually treated as a subphylum, which includes such familiar animals as crabs, lobsters, crayfish, shrimp, krill and barnacles. The 50,000 described species range in size from Stygotantulus stocki at , to the Japanese spider crab with a leg span...
s and bony fishes, the red stingray plays a key ecological role as an apex predator
Apex predator
Apex predators are predators that have no predators of their own, residing at the top of their food chain. Zoologists define predation as the killing and consumption of another organism...
in its environment. Reproduction is aplacental viviparous, with females giving birth to 1 or up to 10 pups at a time. The red stingray is valued as food in Japan; large numbers are caught as bycatch
Bycatch
The term “bycatch” is usually used for fish caught unintentionally in a fishery while intending to catch other fish. It may however also indicate untargeted catch in other forms of animal harvesting or collecting...
and brought to market, which has seemingly led to a population decline in this unprolific species. As a result, the International Union for Conservation of Nature (IUCN) has assessed it as Near Threatened
Near Threatened
Near Threatened is a conservation status assigned to species or lower taxa that may be considered threatened with extinction in the near future, although it does not currently qualify for the threatened status...
.
Taxonomy
The original description of the red stingray was published by Johannes MüllerJohannes Peter Müller
Johannes Peter Müller , was a German physiologist, comparative anatomist, and ichthyologist not only known for his discoveries but also for his ability to synthesize knowledge.-Early years and education:...
and Friedrich Henle
Friedrich Gustav Jakob Henle
Friedrich Gustav Jakob Henle was a German physician, pathologist and anatomist. He is credited with the discovery of the loop of Henle in the kidney. His essay "On Miasma and Contagia" was an early argument for the germ theory of disease...
in their 1841 Systematische Beschreibung der Plagiostomen under the name Trygon akajei, based on an earlier account of "Pastinaca akajei" by Heinrich Bürger
Heinrich Bürger
Heinrich Bürger was a by birth German physicist, biologist and botanist employed by the Dutch government, and an entrepreneur. He was an important person for the study of Japanese fauna and flora.-Background:Bürger's exact birth date is unknown...
. Subsequent authors have placed the genus Trygon in synonymy
Synonym (taxonomy)
In scientific nomenclature, a synonym is a scientific name that is or was used for a taxon of organisms that also goes by a different scientific name. For example, Linnaeus was the first to give a scientific name to the Norway spruce, which he called Pinus abies...
with Dasyatis. A lectotype
Lectotype
In botanical nomenclature and zoological nomenclature, a lectotype is a kind of name-bearing type. When a species was originally described on the basis of a name-bearing type consisting of multiple specimens, one of those may be designated as the lectotype...
for this species was designated by Marinus Boeseman in 1947. Other common name
Common name
A common name of a taxon or organism is a name in general use within a community; it is often contrasted with the scientific name for the same organism...
s for the red stingray include brown stingray, estuary stingaree, Japanese red stingray, Japanese stingray, red skate, whip ray, whip stingray, and yellow stingray.
Distribution and habitat
The red stingray may be endemic to the northwestern Pacific OceanPacific Ocean
The Pacific Ocean is the largest of the Earth's oceanic divisions. It extends from the Arctic in the north to the Southern Ocean in the south, bounded by Asia and Australia in the west, and the Americas in the east.At 165.2 million square kilometres in area, this largest division of the World...
; it is found throughout Japan
Japan
Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...
ese coastal waters from Hokkaidō
Hokkaido
, formerly known as Ezo, Yezo, Yeso, or Yesso, is Japan's second largest island; it is also the largest and northernmost of Japan's 47 prefectural-level subdivisions. The Tsugaru Strait separates Hokkaido from Honshu, although the two islands are connected by the underwater railway Seikan Tunnel...
to Okinawa, and also occurs off Korea
Korea
Korea ) is an East Asian geographic region that is currently divided into two separate sovereign states — North Korea and South Korea. Located on the Korean Peninsula, Korea is bordered by the People's Republic of China to the northwest, Russia to the northeast, and is separated from Japan to the...
, mainland China
Mainland China
Mainland China, the Chinese mainland or simply the mainland, is a geopolitical term that refers to the area under the jurisdiction of the People's Republic of China . According to the Taipei-based Mainland Affairs Council, the term excludes the PRC Special Administrative Regions of Hong Kong and...
and Taiwan
Taiwan
Taiwan , also known, especially in the past, as Formosa , is the largest island of the same-named island group of East Asia in the western Pacific Ocean and located off the southeastern coast of mainland China. The island forms over 99% of the current territory of the Republic of China following...
. This species has been reported from as far as Thailand
Thailand
Thailand , officially the Kingdom of Thailand , formerly known as Siam , is a country located at the centre of the Indochina peninsula and Southeast Asia. It is bordered to the north by Burma and Laos, to the east by Laos and Cambodia, to the south by the Gulf of Thailand and Malaysia, and to the...
, the Philippines
Philippines
The Philippines , officially known as the Republic of the Philippines , is a country in Southeast Asia in the western Pacific Ocean. To its north across the Luzon Strait lies Taiwan. West across the South China Sea sits Vietnam...
, Fiji
Fiji
Fiji , officially the Republic of Fiji , is an island nation in Melanesia in the South Pacific Ocean about northeast of New Zealand's North Island...
, and Tuvalu
Tuvalu
Tuvalu , formerly known as the Ellice Islands, is a Polynesian island nation located in the Pacific Ocean, midway between Hawaii and Australia. Its nearest neighbours are Kiribati, Nauru, Samoa and Fiji. It comprises four reef islands and five true atolls...
. However, whether these records truly represent D. akajei has yet to be determined. The red stingray is commonly encountered in sandy areas close to shore and in bay
Bay
A bay is an area of water mostly surrounded by land. Bays generally have calmer waters than the surrounding sea, due to the surrounding land blocking some waves and often reducing winds. Bays also exist as an inlet in a lake or pond. A large bay may be called a gulf, a sea, a sound, or a bight...
s at a depth of 10 m (32.8 ft) or more, but also inhabits muddy flats, coral reef
Coral reef
Coral reefs are underwater structures made from calcium carbonate secreted by corals. Coral reefs are colonies of tiny living animals found in marine waters that contain few nutrients. Most coral reefs are built from stony corals, which in turn consist of polyps that cluster in groups. The polyps...
s, and estuaries.
Description
The red stingray can grow to 2 m (6.6 ft) long and 0.66 m (2.2 ft) across, though most do not exceed 1 m (3.3 ft) in length. The maximum recorded weight is 10.7 kg (23.6 lb). It has a diamond-shaped pectoral fin disc wider than long, with nearly straight front margins converging to a triangular snout. The small eyes are slightly elevated, and followed by spiracleSpiracle
Spiracles are openings on the surface of some animals that usually lead to respiratory systems.-Vertebrates:The spiracle is a small hole behind each eye that opens to the mouth in some fishes. In the primitive jawless fish the first gill opening immediately behind the mouth is essentially similar...
s that are almost twice as large. There is a thick flap of skin between the large nares. The teeth are arranged with a quincunx
Quincunx
A quincunx is a geometric pattern consisting of five points arranged in a cross, that is five coplanar points, four of them forming a square or rectangle and a fifth at its center...
pattern into a pavement-like surface. Females and juveniles have blunt teeth, while adult males have pointed, recurved teeth. There is a row of 3 papilla
Papilla (fish mouth structure)
The papilla, in certain kinds of fish, particularly rays, sharks, and catfish, are small lumps of dermal tissue found in the mouth, where they are "distributed uniformly on the tongue, palate, and pharynx"...
e across the floor of the mouth, sometimes with up to 2 pairs of accessory papillae alongside.
The tail is whip-like and measures 1–1.5 times as long as the disc is wide. A long, serrated spine originates in the first third of the tail, and is followed by a low dorsal keel and a ventral fin fold. Young rays have smooth skin, while adults have a patch of small dermal denticles between and behind the eyes, and a row of thorns along the midline of the back. There are 1–6 tubercles in front of the tail spine, and numerous small denticles behind. This species is plain brown above, often with yellow or orange coloring before the eyes, behind the spiracles, around the disc margin, and laterally on the tail in front of the spine. The tail darkens to nearly black towards the tip and on the ventral fin fold. The underside is white with bright orange-red patches. The Mekong freshwater stingray
Mekong freshwater stingray
The Mekong freshwater stingray, Dasyatis laosensis, is a species of stingray in the family Dasyatidae, restricted to the Mekong and Chao Phraya Rivers in Laos and Thailand. Measuring up to across, this ray has an oval pectoral fin disc, a tail with both upper and lower fin folds, and a midline row...
(D. laosensis) is also characterized by orange ventral coloration and has some similar meristic counts to this species, but differs in disc shape, denticle coverage, and dorsal coloration.
Biology and ecology
As an apex predatorApex predator
Apex predators are predators that have no predators of their own, residing at the top of their food chain. Zoologists define predation as the killing and consumption of another organism...
in nearshore demersal food web
Food web
A food web depicts feeding connections in an ecological community. Ecologists can broadly lump all life forms into one of two categories called trophic levels: 1) the autotrophs, and 2) the heterotrophs...
s, the red stingray plays a significant ecological role. Crustacean
Crustacean
Crustaceans form a very large group of arthropods, usually treated as a subphylum, which includes such familiar animals as crabs, lobsters, crayfish, shrimp, krill and barnacles. The 50,000 described species range in size from Stygotantulus stocki at , to the Japanese spider crab with a leg span...
s are the most important component of its diet, followed by small bony fishes and then annelid worms, while molluscs are seldom consumed. In Tokyo Bay
Tokyo Bay
is a bay in the southern Kantō region of Japan. Its old name was .-Geography:Tokyo Bay is surrounded by the Bōsō Peninsula to the east and the Miura Peninsula to the west. In a narrow sense, Tokyo Bay is the area north of the straight line formed by the on the Miura Peninsula on one end and on...
, important crustacean prey species are Crangon affinis for males, Oratosquilla ijimai for females, and Anisomysis ijimai for juveniles; the most important fish prey species is Sardinops melanostictus, followed by Conger myriaster
Conger myriaster
Whitespotted conger, Conger myriaster, is in the family of conger eel. Widespread in the Northwest Pacific near the coasts of Japan, Korean Peninsula, also in the East China Sea.Conger myriaster inhabit shallow sea bottom sand and mud. Conger myriaster is also consumed as food. Maximum total...
. Like other stingrays, the red stingray is aplacental viviparous. During courtship, the male follows the female and bites at her pectoral fin disc, using his pointed teeth to gain a grip for copulation. The litter size has been variously reported as only 1 or up to 10. Males mature sexually
Sexual maturity
Sexual maturity is the age or stage when an organism can reproduce. It is sometimes considered synonymous with adulthood, though the two are distinct...
at a disc width of 35–40 cm (13.8–15.7 in), and females at a disc width of 50–55 cm (19.7–21.7 in).
Known parasites of the red stingray include the tapeworms Acanthobothrium macrocephalum, Rhodobothrium pulvinatum, and Tetragonocephalum akajeinensis, the monogenea
Monogenea
Monogenea are a group of largely ectoparasitic members of the flatworm phylum Platyhelminthes, class Monogenea.-Characteristics:Monogenea are very small parasitic flatworms mainly found on skin or gills of fish....
ns Dendromonocotyle akajeii and Heterocotyle chinensis, the leech
Leech
Leeches are segmented worms that belong to the phylum Annelida and comprise the subclass Hirudinea. Like other oligochaetes such as earthworms, leeches share a clitellum and are hermaphrodites. Nevertheless, they differ from other oligochaetes in significant ways...
Pterobdella amara, the nematode
Nematode
The nematodes or roundworms are the most diverse phylum of pseudocoelomates, and one of the most diverse of all animals. Nematode species are very difficult to distinguish; over 28,000 have been described, of which over 16,000 are parasitic. It has been estimated that the total number of nematode...
s Porrocaecum laymani and Terranova amoyensis, the copepod
Copepod
Copepods are a group of small crustaceans found in the sea and nearly every freshwater habitat. Some species are planktonic , some are benthic , and some continental species may live in limno-terrestrial habitats and other wet terrestrial places, such as swamps, under leaf fall in wet forests,...
Trebius akajeii, and the pranzia larva
Larva
A larva is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle...
e of the isopod Gnathia capillata.
Human interactions
The venomVenom
Venom is the general term referring to any variety of toxins used by certain types of animals that inject it into their victims by the means of a bite or a sting...
ous tail spine of the red stingray is potentially injurious to humans. The Ainu
Ainu people
The , also called Aynu, Aino , and in historical texts Ezo , are indigenous people or groups in Japan and Russia. Historically they spoke the Ainu language and related varieties and lived in Hokkaidō, the Kuril Islands, and much of Sakhalin...
once used the dried tail spine, with the toxic sheath intact, as a weapon. This species is an incidental catch
Bycatch
The term “bycatch” is usually used for fish caught unintentionally in a fishery while intending to catch other fish. It may however also indicate untargeted catch in other forms of animal harvesting or collecting...
of commercial fisheries
Commercial fishing
Commercial fishing is the activity of catching fish and other seafood for commercial profit, mostly from wild fisheries. It provides a large quantity of food to many countries around the world, but those who practice it as an industry must often pursue fish far into the ocean under adverse conditions...
targeting flounder
Flounder
The flounder is an ocean-dwelling flatfish species that is found in coastal lagoons and estuaries of the Northern Atlantic and Pacific Oceans.-Taxonomy:There are a number of geographical and taxonomical species to which flounder belong.*Western Atlantic...
and other bottom-dwelling fishes, using bottom trawls, gillnet
Gillnet
Gillnetting is a common fishing method used by commercial and artisanal fishermen of all the oceans and in some freshwater and estuary areas. The gillnet also is used by fisheries scientists to monitor fish populations. Because gillnets can be so effective their use is closely monitored and...
s, set nets
Fishing net
A fishing net or fishnet is a net that is used for fishing. Fishing nets are meshes usually formed by knotting a relatively thin thread. Modern nets are usually made of artificial polyamides like nylon, although nets of organic polyamides such as wool or silk thread were common until recently and...
, and line gear. It is valued as food in Japan, especially in the Tokyo Bay area where it is consumed in autumn and winter; it may be prepared hard boiled, with miso soup
Miso soup
is a traditional Japanese soup consisting of a stock called "dashi" into which is mixed softened miso paste. Many ingredients are added depending on regional and seasonal recipes, and personal preference.-Miso paste:...
, or as kamaboko
Kamaboko
is a type of cured surimi, a Japanese processed seafood product, in which various white fish are pureed, combined with additives such as MSG, formed into distinctive loaves, and then steamed until fully cooked and firm. The steamed loaves are then sliced and served unheated with various dipping...
. However, the small size of the red stingray limits its economic importance. Annual catches reported by Japanese fisheries have steadily declined from 20,000 tons in 1950 to varying between 3,959 and 5,388 tons from 1997 to 2004. Such apparent depletion, coupled with continuing heavy fishing pressure and a slow reproductive rate, have led the International Union for Conservation of Nature (IUCN) to assess this species as Near Threatened
Near Threatened
Near Threatened is a conservation status assigned to species or lower taxa that may be considered threatened with extinction in the near future, although it does not currently qualify for the threatened status...
.