The Mekong giant catfish, Pangasianodon gigas, is a
speciesIn 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
catfishCatfishes are a diverse group of ray-finned fish. Named for their prominent barbels, which resemble a cat's whiskers, catfish range in size and behavior from the heaviest and longest, the Mekong giant catfish from Southeast Asia and the second longest, the wels catfish of Eurasia, to detritivores...
(
orderIn scientific classification used in biology, the order is# a taxonomic rank used in the classification of organisms. Other well-known ranks are life, domain, kingdom, phylum, class, family, genus, and species, with order fitting in between class and family...
Siluriformes) in the
shark catfishThe shark catfishes are a family, the Pangasiidae, of catfishes found in fresh and brackish waters across southern Asia, from Pakistan to Borneo. Among the 30-odd members of this family is the plant-eating, endangered Mekong giant catfish Pangasianodon gigas, one of the largest known freshwater...
familyIn 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...
(family Pangasiidae), native to the
MekongThe Mekong is a river that runs through China, Burma, Laos, Thailand, Cambodia and Vietnam. It is the world's 10th-longest river and the 7th-longest in Asia. Its estimated length is , and it drains an area of , discharging of water annually....
basin in
Southeast AsiaSoutheast Asia, South-East Asia, South East Asia or Southeastern Asia is a subregion of Asia, consisting of the countries that are geographically south of China, east of India, west of New Guinea and north of Australia. The region lies on the intersection of geological plates, with heavy seismic...
.
Species characteristics
The Mekong giant catfish is perhaps the most interesting and most threatened species in the Mekong river. For this reason conservationists have chosen it as a sort of “flagship” species to promote conservation on the Mekong. With recorded sizes of up to 10.5ft (3.2m) and 660lb (300kg), the Mekong’s giant catfish currently holds the Guinness Book of World Records position for the world’s largest freshwater fish. Although research projects are currently ongoing, relatively little is known about this species. Historically, the fish had a natural range that reached from the lower Mekong in Vietnam (above the tidally influenced brackish water of the river’s delta) all the way to the northern reaches of the river in the Yunnan province of China, spanning almost the entire 4,800 km length of the river. Due to threats, this species no longer inhabits the majority of its original
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...
; it is now believed to only exist in small, isolated populations in the middle Mekong region. Fish congregate during the beginning of the rainy season and migrate upstream to spawn. They live primarily in the main channel of the river, where the water depth is over 10m while researchers, fishermen and officials have found this species in the Tonle Sap river and lake in Cambodia, a UNESCO Biosphere reserve. In the past, fishermen have reported the fish in a number of the Mekong’s tributaries; today, however, essentially no sightings are reported outside of the main Mekong river channel and the Tonle Sap region.
In infancy, this species feeds on zooplankton in the river and is known to be cannibalistic. After approximately one year, the fish becomes herbivorous, feeding on filamentous algae, probably ingesting larvae and periphyton accidentally. The fish likely obtains its food from algae growing on submerged rocky surfaces, as it does not have any sort of dentition.
Conservation
Endemic to the lower half of the Mekong river, this catfish is in danger of extinction due to overfishing, as well as the decrease in water quality due to development and upstream damming by the
People's Republic of ChinaChina , officially the People's Republic of China , is the most populous country in the world, with over 1.3 billion citizens. Located in East Asia, the country covers approximately 9.6 million square kilometres...
. The current
IUCN Red ListThe IUCN Red List of Threatened Species , founded in 1963, is the world's most comprehensive inventory of the global conservation status of biological species. The International Union for Conservation of Nature is the world's main authority on the conservation status of species...
for fishes classes the species as Critically Endangered; the number living in the wild is unknown, but catch data indicate the population has fallen by 80 percent in the last 14 years.
It is also listed in Appendix I of CITES, banning international trade.
In The Anthropologists' Cookbook (1977), Jessica Kuper noted the importance of the pa beuk to the Lao people and remarked, "In times gone by, this huge fish, which is found only in the Mekong, was fairly plentiful; but in the last few years the number taken annually has dwindled to forty, thirty or twenty, and perhaps in 1976 even fewer. This is sad, as it is a noble fish and a mysterious one, revered by the Lao."
Fishing for the Mekong giant catfish is illegal in the wild in
ThailandThailand , 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...
,
LaosLaos Lao: ສາທາລະນະລັດ ປະຊາທິປະໄຕ ປະຊາຊົນລາວ Sathalanalat Paxathipatai Paxaxon Lao, officially the Lao People's Democratic Republic, is a landlocked country in Southeast Asia, bordered by Burma and China to the northwest, Vietnam to the east, Cambodia to the south and Thailand to the west...
, and
CambodiaCambodia , officially known as the Kingdom of Cambodia, is a country located in the southern portion of the Indochina Peninsula in Southeast Asia...
, but the bans appear to be ineffective, with the fish continuing to be caught in all three countries.
However, in recognition of the threat to the species, nearly 60 Thai fishermen agreed to stop catching the endangered catfish in June 2006, to mark the 60th anniversary of
Bhumibol AdulyadejBhumibol Adulyadej is the current King of Thailand. He is known as Rama IX...
's ascension to the throne of Thailand.
Thailand is the only country that allows fishing for private stocks of Mekong giant catfish. This helps save the species as lakes purchase the small fry from the government breeding program, generating extra income that allows the breeding program to function.
Fishing lakes like Bung Sam Ran in Bangkok have the species up to 140 kg;. The most common size landed is 18 kg, although there are some companies that specialise in landing the larger fish.
The fish are not aggressive, but very powerful, as they evolved in the running waters of the Mekong River where the current flow can be high at times.
The Mekong giant catfish can also be seen occasionally in the
Chao Phraya RiverThe Chao Phraya is a major river in Thailand, with its low alluvial plain forming the centre of the country. It runs through Bangkok, the capital city, and then empties into the Gulf of Thailand.-Etymology:...
. When feeding fish at the Bangkok temples along the river, the fish will be seen at times. The largest spotted to date has been about 25 kg.
The species needs to reach 50 to 70 kg to breed, and unfortunately it does not breed in lakes.
The Thailand Fishery Department has instituted a breeding program to restock the Mekong River. However, it is yet to be seen if the fish will spawn.
Size
Attaining an unconfirmed length of 3 m, the Mekong giant catfish grows extremely quickly, reaching a mass of 150 to 200
kgThe kilogram or kilogramme , also known as the kilo, is the base unit of mass in the International System of Units and is defined as being equal to the mass of the International Prototype Kilogram , which is almost exactly equal to the mass of one liter of water...
in only six years.
The largest catch recorded in Thailand since record-keeping began in 1981 was a female measuring 2.7 m (roughly 9 feet) in length and weighing 293
kgThe kilogram or kilogramme , also known as the kilo, is the base unit of mass in the International System of Units and is defined as being equal to the mass of the International Prototype Kilogram , which is almost exactly equal to the mass of one liter of water...
(646
lbThe pound or pound-mass is a unit of mass used in the Imperial, United States customary and other systems of measurement...
). This specimen, caught in 2005, is widely recognized as the largest freshwater fish ever caught (although
sturgeonSturgeon is the common name used for some 26 species of fish in the family Acipenseridae, including the genera Acipenser, Huso, Scaphirhynchus and Pseudoscaphirhynchus. The term includes over 20 species commonly referred to as sturgeon and several closely related species that have distinct common...
can far exceed this size, they can be anadromous). Thai Fisheries officials stripped the fish of its eggs as part of a breeding programme, intending then to release it, but the fish died in captivity and was sold as food to local villagers.
Grey to white in colour and lacking stripes, the Mekong giant catfish is distinguished by the near-total lack of
barbelA barbel on a fish is a slender, whiskerlike tactile organ near the mouth. Fish that have barbels include the catfish, the carp, the goatfish, sturgeon, the zebrafish and some species of shark...
s and the absence of teeth.
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