Giant guitarfish
Encyclopedia
The giant guitarfish, Rhynchobatus djiddensis, is a species of guitarfish
in the family Rhynchobatidae.
, but recent evidence has shown that it, as traditionally defined, actually was a species complex
consisting of 4 different species. In addition to the giant guitarfish, this complex includes the white-spotted guitarfish
, the broadnose wedgefish
and possibly the smoothnose wedgefish
. With these as separate species, the giant guitarfish has a relatively restricted range: It is found only in the Red Sea
and the tropical western Indian Ocean
as far south as South Africa
.
(though some white-spotted guitarfish are essentially unspotted too). It is ovoviviparous, and a female can give birth to litter
s of up to 10 young.
s, lobster
s, squid
and small fish
.
s or reef flats, but they will sometimes venture into the brackish waters of estuaries
.
s. It is listed as vulnerable
on the IUCN red list as its population are believed to have declined significantly due to unregulated high levels of exploitation for its flesh and fin
s; the latter for shark fin soup
. Its low fecundity
and presumed slow growth rate make it highly vulnerable to unsustainable exploitation.
Guitarfish
The guitarfish are a family, Rhinobatidae, of rays. The guitarfish are known for an elongated body with a flattened head and trunk and small ray like wings. The combined range of the various species is tropical, subtropical and temperate waters worldwide. They often travel in large...
in the family Rhynchobatidae.
Taxonomy and range
The giant guitarfish was previously believed to range throughout a large part of the Indo-PacificIndo-Pacific
The Indo-Pacific is a biogeographic region of the Earth's seas, comprising the tropical waters of the Indian Ocean, the western and central Pacific Ocean, and the seas connecting the two in the general area of Indonesia...
, but recent evidence has shown that it, as traditionally defined, actually was a species complex
Species complex
A species complex is a group of closely related species, where the exact demarcation between species is often unclear or cryptic owing to their recent and usually still incomplete reproductive isolation. Ring species, superspecies and cryptic species complex are example of species complex...
consisting of 4 different species. In addition to the giant guitarfish, this complex includes the white-spotted guitarfish
Rhynchobatus australiae
Rhynchobatus australiae, also called the white-spotted guitarfish or white-spotted wedgefish, is a species of fish in the Rhynchobatidae family. It is found in Australia, Indonesia, the Philippines, and Thailand. Its natural habitats are open seas and shallow seas...
, the broadnose wedgefish
Broadnose wedgefish
The broadnose wedgefish is a species of fish in the Rhynchobatidae family. It is found in Indonesia, Malaysia, the Philippines, Singapore, and Thailand. Its natural habitats are open seas, coral reefs, estuarine waters, and coastal saline lagoons. It is threatened by habitat loss.-References:*...
and possibly the smoothnose wedgefish
Smoothnose wedgefish
The smoothnose wedgefish is a species of fish in the Rhynchobatidae family. It is found in Australia, Bangladesh, China, India, Japan, Oman, Pakistan, Sri Lanka, and Tanzania. Its natural habitat is shallow seas. It is threatened by habitat loss.-Source:* McAuley, R. & Compagno, L.J.V. 2003. . ...
. With these as separate species, the giant guitarfish has a relatively restricted range: It is found only in the Red Sea
Red Sea
The Red Sea is a seawater inlet of the Indian Ocean, lying between Africa and Asia. The connection to the ocean is in the south through the Bab el Mandeb strait and the Gulf of Aden. In the north, there is the Sinai Peninsula, the Gulf of Aqaba, and the Gulf of Suez...
and the tropical western Indian Ocean
Indian Ocean
The Indian Ocean is the third largest of the world's oceanic divisions, covering approximately 20% of the water on the Earth's surface. It is bounded on the north by the Indian Subcontinent and Arabian Peninsula ; on the west by eastern Africa; on the east by Indochina, the Sunda Islands, and...
as far south as South Africa
South Africa
The Republic of South Africa is a country in southern Africa. Located at the southern tip of Africa, it is divided into nine provinces, with of coastline on the Atlantic and Indian oceans...
.
Description
A large fish reaching up to 3.1m long and weighing as much as 227 kg. The colour underneath is white and overall dark greyish or olive above. Large individuals lack the distinct white spots of the closely related white-spotted guitarfishRhynchobatus australiae
Rhynchobatus australiae, also called the white-spotted guitarfish or white-spotted wedgefish, is a species of fish in the Rhynchobatidae family. It is found in Australia, Indonesia, the Philippines, and Thailand. Its natural habitats are open seas and shallow seas...
(though some white-spotted guitarfish are essentially unspotted too). It is ovoviviparous, and a female can give birth to litter
Litter (animal)
A litter is the offspring at one birth of animals from the same mother and usually from one set of parents. The word is most often used for the offspring of mammals, but can be used for any animal that gives birth to multiple young. In comparison, a group of eggs and the offspring that hatch from...
s of up to 10 young.
Diet
The giant guitarfish feeds on bivalves, crabCrab
True crabs are decapod crustaceans of the infraorder Brachyura, which typically have a very short projecting "tail" , or where the reduced abdomen is entirely hidden under the thorax...
s, lobster
Lobster
Clawed lobsters comprise a family of large marine crustaceans. Highly prized as seafood, lobsters are economically important, and are often one of the most profitable commodities in coastal areas they populate.Though several groups of crustaceans are known as lobsters, the clawed lobsters are most...
s, squid
Squid
Squid are cephalopods of the order Teuthida, which comprises around 300 species. Like all other cephalopods, squid have a distinct head, bilateral symmetry, a mantle, and arms. Squid, like cuttlefish, have eight arms arranged in pairs and two, usually longer, tentacles...
and small fish
Fish
Fish are a paraphyletic group of organisms that consist of all gill-bearing aquatic vertebrate animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish, as well as various extinct related groups...
.
Habitat
It is a shy fish, found from 2m to 50m depth, inhabiting areas with sandy sea floor. These are generally around coastal reefReef
In nautical terminology, a reef is a rock, sandbar, or other feature lying beneath the surface of the water ....
s or reef flats, but they will sometimes venture into the brackish waters of estuaries
Estuary
An estuary is a partly enclosed coastal body of water with one or more rivers or streams flowing into it, and with a free connection to the open sea....
.
Interaction with man
The giant guitarfish is harmless to humanHuman
Humans are the only living species in the Homo genus...
s. It is listed as vulnerable
Vulnerable species
On 30 January 2010, the IUCN Red List of Threatened Species identified 9694 Vulnerable species, subspecies and varieties, stocks and sub-populations.-References:...
on the IUCN red list as its population are believed to have declined significantly due to unregulated high levels of exploitation for its flesh and fin
Fin
A fin is a surface used for stability and/or to produce lift and thrust or to steer while traveling in water, air, or other fluid media, . The first use of the word was for the limbs of fish, but has been extended to include other animal limbs and man-made devices...
s; the latter for shark fin soup
Shark fin soup
Shark fin soup is a popular soup item of Chinese cuisine usually served at special occasions such as weddings and banquets, or as a luxury item in Chinese culture. The shark fins provide texture while the taste comes from the other soup ingredients.There is controversy over the practice of shark...
. Its low fecundity
Fecundity
Fecundity, derived from the word fecund, generally refers to the ability to reproduce. In demography, fecundity is the potential reproductive capacity of an individual or population. In biology, the definition is more equivalent to fertility, or the actual reproductive rate of an organism or...
and presumed slow growth rate make it highly vulnerable to unsustainable exploitation.