Pangasius

Pangasius
	Pangasius ( Pangasianodon hypophthalmus )
Systematics
Cohort :	Otomorpha
Sub-cohort :	Ostariophysi
Order :	Catfish (Siluriformes)
Family :	Shark catfish (Pangasiidae)
Genre :	Pangasianodon
Type :	Pangasius
Scientific name
	Pangasianodon hypophthalmus
	( Sauvage , 1878)

The pangasius ( Pangasianodon hypophthalmus ) is a freshwater fish from the family of the shark catfish or slim catfish (Pangasiidae) that colonizes the river systems of the Mekong and Mae Nam Chao Phraya ( Chao Phraya River ) in Thailand , Vietnam , Laos and Cambodia .

The species is traditionally fished, but in Southeast Asia it has been increasingly bred in aquaculture for a number of years and marketed worldwide as food fish . The total production amounts to over a million tons per year. A large part of this is exported to Europe , where the fish is popular because of its tender, mild-tasting meat and its low price. The name of the genus Pangasius , to which the species was previously assigned, is used as the German name . The specific epithet hypophthalmus (from ancient Greek ὑπό hypó "under" and ὀφθαλμός ophtalmós "eye") indicates the deep position of the eyes compared to the mouth.

features

Young animals with the typical stripe pattern

The pangasius has the elongated, scaleless body typical of the shark catfish (Pangasiidae). Adult animals with a length of up to 150 centimeters reach a maximum weight of 44 kilograms. They are dark gray with a lighter belly and dark gray to black fins. Very old and large animals turn uniformly gray. As characteristic features of the genus Pangasianodon , the pangasius has a terminal mouth (upper and lower jaws are therefore of equal length), a swim bladder with only one lobe and pelvic fins with eight, rarely nine soft rays. In adult animals, the mouth is also toothless and the barbels on the lower jaw are missing. From the other species of the genus, the Mekong giant catfish , it differs in its significantly smaller size and the less broad head and the construction of the gill trap , which is well developed in the pangasius and about 40 very short rays on the first arch between 15 longer rays wearing.

The dorsal fin has, like many catfish- like, a prickly hard ray, followed by six branched soft rays. An adipose fin is present. The anal fin lies elongated on the belly and has a black stripe in the middle, as do both lobes of the caudal fin . The small pelvic fins sit just in front of the anal fin.

Newly hatched animals are yellowish and almost transparent with pronounced barbels, while older young animals resemble the fully grown ones and have a black stripe along the lateral line organ and another just below it. This pattern fades with age.

The chromosome set consists of 30 pairs ( 2n = 60).

Occurrence

Rear India with the Mekong and Chao Phraya as the distribution area of the Pangasius, as well as walks in the Mekong: Orange - March to May; Dark green - May to September; Red - October to February; Hatching - spawning areas of the southern Mekong population

The species colonizes the major rivers of the Mekong and Mae Nam Chao Phraya ( Chao Phraya River ) in Thailand , Vietnam , Laos and Cambodia . It is believed that the occurrence in the Mekong is divided into a southern population in Cambodia and Vietnam and a northern population in Laos and Thailand by the waterfalls in the Laotian province of Champasak . Catches in the area of the falls, however, indicate some exchange between populations. More detailed genetic studies are only available for the southern population, within which three common , genetically distinguishable sub-populations occur, which may be separated from one another by different spawning times. The spawning area of the southern Mekong population is located in a relatively small area in northern Cambodia between Kratie and the Mekong Falls, that of the northern and Chao Phraya populations are unknown.

Naturalized stocks exist in Bangladesh , Singapore and the Philippines as a result of the introduction to aquaculture. Here the species is considered to be ecologically very problematic due to its voracity and possible competition with native fish.

Way of life and reproduction

Stages of development of the pangasius: freshly hatched, as well as four-day-old larva and 14-day-old fingerling. The black bars correspond to a length of one millimeter

The pangasius is a diurnal fish that lives in groups. Its food spectrum includes algae, aquatic plants, zooplankton, molluscs, insects, organic waste and, in larger animals, also fish, crustaceans and fruits. In addition to breathing through the gills , the species also absorbs air on the surface of the water, with the swim bladder serving as a respiratory organ. The frequency and necessity of this air breathing depends on the oxygen concentration of the surrounding water.

In the course of the year the fish undertake long migrations that correlate with the changing water levels of the populated rivers. From October the animals migrate upstream to the spawning areas, where spawning activity peaks in the months of May to July.

Little is known about their mating behavior. The numerous spherical, sticky eggs have a yellowish to greenish-brown capsule and are deposited on tree roots protruding from the bank into the water. The amount of eggs produced increases with the size of the females and reaches up to two hundred thousand eggs per kilogram of body weight. Some large females are likely to spawn twice a year. The approximately three millimeter long larvae hatch after 24 to 36 days and can be drifted downstream. After a development period of about twelve days, the young animals begin to take in food and air. The sexual maturity is reached after three to four years at a length of about fifty centimeters and weighing about three kilograms. The maximum age is a little over ten years.

After laying their eggs, the old animals migrate to the feeding grounds in the extensive floodplains of the Mekong, Chao Phraya and Tonle Sap and penetrate into the Mekong Delta . With the falling water levels in the months of September to December, the animals return to the main streams, where they then mainly stay in deep water.

Use by humans

Use as food

Pangasius fillet

In addition to traditional fishing for wild stocks, pangasius is increasingly being bred in aquaculture . The main producing countries are Vietnam and Thailand , and to a lesser extent China , Myanmar , Bangladesh and India . The pangasius has also been bred in the USA for several years . Flooded rice fields are mainly used. In Vietnam alone, the production of P. hypophthalmus and the closely related species Pangasius bocourti (trade name "Basa") rose from 400,000 tons in 2005 to over one million tons in 2007 with a market value of over 700 million US dollars.

The animals are kept in specially dug ponds or in cages within existing bodies of water in mono- or mixed culture and mainly fed with by-products and waste products from agriculture and fish farming, such as rice and fish meal . In some cases, a strong growth of algae is stimulated in the ponds by adding nitrogen fertilizers or faeces. In the context of intensive breeding, however, industrially manufactured high-performance feed is also increasingly being used. The fish grow quickly and can be kept in very high densities of up to 150 animals per cubic meter, but then susceptible to various diseases and parasites, which in some cases have to be dealt with with high levels of medication. After eight months, the animals reach the slaughter weight of around one kilogram. Since the females do not spawn on their own in captivity, hormone injections are necessary to trigger the laying of eggs or to replenish the population via wild-caught animals.

Frozen fillets are exported from the producing countries to the rest of the world. The main buyers today are the countries of the European Union , where the species is predominantly available as "Pangasius", in German-speaking countries less often as "Slim catfish". The meat is white, rich in water, low in fat, cholesterol and bones, and has a mild taste. According to popular belief, the fish has little or no taste of its own. Due to the low price, fillets of P. hypophthalmus have sometimes been sold as more expensive fish, for example plaice or as pangasius bocourti . Furthermore, forbidden antibiotics or malachite green are sometimes detected in imported fish from Southeast Asia in Europe , which are used in intensive farming to treat diseases.

Aquaristics

Young fish in particular are often kept as ornamental fish in Southeast Asia due to their striking shape and shiny flanks . The species is usually sold as a shark catfish in specialist aquarium stores. Due to the size reached by adult animals and the way of life in groups, the pangasius is not very suitable for home aquariums. He is also very scared and easily injured on the aquarium walls when trying to escape. The species prefers water temperatures of 22 to 26 ° C, a pH value of 6.5 to 7.5 and a water hardness of 2 to 29 ° dH.

Danger

Since the pangasius does not reach sexual maturity until it is over three years old, it is assumed that severely decimated stocks can only recover slowly. Therefore, the species is likely to be very sensitive to overfishing. The wild stock is fished intensively with nets, fishing rods and partly with explosives, especially in Cambodia, and accounts for around 10 to 15% of the total catch of freshwater fish. Another particular threat is the catching of fry to feed the aquacultures . For this purpose, swimming baskets are equipped with nylon traps and mosquito nets to catch even the very small larvae. This type of fishing has been banned in Cambodia since 1994 and in Vietnam since 2000.

In 1999, the population of the pangasius in Cambodia was estimated by the local fisheries ministry at 20 to 30 million adult animals. Although there are no precise figures on the development of the population, the catches indicate a decline in game populations in the Mekong .

Systematics

The common name "Pangasius" is derived from the genus Pangasius of the same name , to which the species was previously assigned as Pangasius hypophthalmus ("Haiwels"). Due to morphological and molecular studies, the species is now placed in the genus Pangasianodon together with the Mekong giant catfish ( Pangasianodon gigas ) . Pangasius sutchi (Fowler, 1937), from which the common English name "sutchi catfish" is derived, is a more recent synonym that is still used at times in aquaristics . Beyond that, no subspecies are described.

Movies

Michael Höft, Thomas Wagner: The Pangasius Lie. NDR, August 2011, archived from the original on June 14, 2015 ; accessed on June 14, 2015 .

swell

Pangasius on Fishbase.org (English)
P. Chheng, E. Baran, BT Touch: Synthesis of all published information on Sutchi catfish Pangasius hypophthalmus (“trey pra”) based on FishBase 2004 . WorldFish Center and Inland Fisheries Research and Development Institute, Phnom Penh, Cambodia 2004
N. Van Zalinge, Lieng Sopha, Ngor Peng Bun, Heng Kong, J. Jørgensen: Status of the Mekong Pangasianodon hypophthalmus resources, with special reference to the stock shared between Cambodia and Viet Nam . In: MRC Technical Paper . No. 1 . Mekong River Commission, 2002, ISSN 1683-1489 (English, mrcmekong.org [PDF]).
Axel Zarske: Pangasius. In: Claus Schaefer, Torsten Schröer (Hrsg.): The large lexicon of aquaristics. Eugen Ulmer, Stuttgart 2004, ISBN 3-8001-7497-9 , p. 739 f.

Individual evidence

^ Wilhelm Gemoll: Greek-German school and hand dictionary. Munich / Vienna 1965.

↑ ^a ^b ^c Asiful Islam: Embryonic and larval development of Thai Pangas (Pangasius sutchi Fowler, 1937) . In: Development Growth & Differentiation . tape 47 , no. 1 , January 2005, p. 1–6 , doi : 10.1111 / j.1440-169x.2004.00773.x (English).

↑ ^a ^b T. R. Roberts, C. Vidthayanon: Systematic revision of the Asian catfish family Pangasiidae, with biological observations and descriptions of three new species . In: Proceedings of the Academy of Natural Sciences of Philadelphia . tape 143 , 1991, pp. 97-144 (English).

^ WJ Rainboth: Fishes of the Cambodian Mekong. FAO species identification sheets for fishery purposes . Food and Agriculture Organization, Rome 1996 (English).

↑ ^a ^b ^c ^d ^e Pangasius on Fishbase.org (English)

↑ ^a ^b Poulsen, Valbo-Jørgensen (ed.): Fish migrations and spawning habits in the Mekong mainstream: a survey using local knowledge (basin-wide) . Mekong River Commission, Phnom Penh 2001 (English).

^ N. So, GE Maes, FAM Volckaert: High genetic diversity in cryptic populations of the migratory sutchi catfish Pangasianodon hypophthalmus in the Mekong River . In: Heredity . tape 96 , 2006, p. 166-174 , doi : 10.1038 / sj.hdy.6800781 (English).

↑ Shuvashish P. Barua, M. Monirul H. Khan, AHM Ali Reza: The Status of Alien Invasive Species in Bangladesh and their Impact on the Ecosystems . IUCN-The World Conservation Union, Dhanmodi, Dhaka, Bangladesh 2000.

↑ Morris W. Browman, Donald L. Kramer: Pangasius sutchi (Pangasiidae) to air-breathing catfish did uses the swimbladder as of accessory respiratory organ . In: Copeia . tape 4 , no. 4 , 1985, pp. 994-998 , JSTOR : 1445253 (English, abstract).

↑ ^a ^b N. Van Zalinge, Lieng Sopha, Ngor Peng Bun Heng Kong, J. Jørgensen: Status of the Mekong Pangasianodon hypophthalmus resources, with special reference to the stock shared between Cambodia and Viet Nam . In: MRC Technical Paper . No. 1 . Mekong River Commission, 2002, ISSN 1683-1489 (English, mrcmekong.org [PDF]).

↑ Eric Baran: Fish migration triggers in the Lower Mekong Basin and other tropical freshwater systems . In: MRC Technical Paper . No. 14 . Mekong River Commission, 2006, ISSN 1683-1489 (English, mrcmekong.org [PDF]).

↑ Barbara Hardinghaus: Death of a fish finger . In: Der Spiegel . No. 11 , 2009, p. 127 ( online ).

↑ Flavio Corsin: Pangasius Aquaculture Dialogue . World Wildlife Fund, 2008 ( worldwildlife.org [PDF]).

^ Zaher, M., MA Mazid: Aquafeeds and feeding strategies in Bangladesh . In: MB New, AGJ Tacon, I. Csavas (Ed.): Proceedings of the FAO / AADCP Regional Expert Consultation on Farm-Made Aquafeeds . FAO-RAPA / AADCP, Bangkok, Thailand 1993, p. 161-180 ( fao.org ).

^ Wing-Keong Ng, Myint Soe and Hla Phone: Aquafeeds in Myanmar: A change from farm-made to factory-made feeds . In: Aquaculture Asia . tape 12 , no. 3 , 2007, p. 7–12 (English, aquacomm.fcla.edu [PDF]).

↑ Mohammed Mokhlesur Rahman, Md. Shahidul Islam, Govinda Chandra Halder, Masaru Tanaka: Cage culture of sutchi catfish, Pangasius sutchi (Fowler 1937): effects of stocking density on growth, survival, yield and farm profitability . In: Aquaculture Research . tape 37 , no. 1 , January 2006, p. 33-39 , doi : 10.1111 / j.1365-2109.2005.01390.x (English).

↑ Marc Legendrea, Jacques Slembroucka, Jojo Subagjab, Anang Hari Kristanto: Ovulation rate, latency period and ova viability after GnRH- or hCG-induced breeding in the Asian catfish Pangasius hypophthalmus (Siluriformes, Pangasiidae) . In: Aquatic Living Resources . tape 13 , 2000, pp. 145–151 (English, alr-journal.org [PDF]). alr-journal.org ( Memento of the original dated February 4, 2009 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. @1@ 2
↑ Elena Orban, Teresina Nevigatoa, Gabriella di Lenaa, Maurizio Mascia, Irene Casinia, Loretta Gambellia, Roberto Capronia: New trends in the seafood market. Sutchi catfish (Pangasius hypophthalmus) fillets from Vietnam: Nutritional quality and safety aspects . In: Food Chemistry . tape 110 , no. 2 , 2008, p. 383–389 (English, abstract ).
↑ Pangasius , In: Der Große Larousse Gastronomique - The standard work for kitchen, culinary art, eating culture, Christian Verlag, 2nd edition, Munich 2009, ISBN 978-3-88472-900-7 , (Larousse, Paris 2007), p. 634 .
↑ Jan Grossarth: The rise of Pangasius . In: FAZ , August 10, 2010, p. 18.
↑ Deutsche See Fischmanufaktur: Taste: Pangasius is versatile.
^ H. Rehbein: New Fish on the German Market: Consumer Protection against Fraud by Identification of Species . In: Journal for Consumer Protection and Food Safety . tape 3 , no. 1 , February 2008, p. 49-53 , doi : 10.1007 / s00003-007-0301-9 (English).
↑ Frank Brendel, Udo Ludwig : Delicacies with poison . In: Der Spiegel . No. 23 , 2006, p. 58 ( online ).
↑ Axel Zarske: Pangasius hypophthalmus. In: Claus Schaefer, Torsten Schröer (Hrsg.): The large lexicon of aquaristics. Eugen Ulmer, Stuttgart 2004, ISBN 3-8001-7497-9 , p. 739.
^ Ngor Peng Bun: Catfish fry collection in Kandal / Phnom Penh in the Mekong River . MRC Fisheries Program, 1999 (English, mekonginfo.org [PDF]). mekonginfo.org ( Memento of the original from September 23, 2011 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. @1@ 2
^ N. So, T. Nao: National Aquaculture Development Review (1984-1999) and Aquaculture Development Plan (2000-2020) . Department of Fisheries, Ministry of Agriculture, Forestry and Fisheries, Phnom Penh 1999 (English).
^ Axel Zarske: Pangasius hypophthalmus (Sauvage, 1878). Shark catfish. In: Claus Schaefer, Torsten Schröer (Hrsg.): The large lexicon of aquaristics. Eugen Ulmer, Stuttgart 2004, ISBN 3-8001-7497-9 , p. 739.
↑ L. Pouyard, GG Teugels, R. Gustiano, M. Legendre: Contribution to the phylogeny of pangasiid catfishes based on allozymes and mitochondrial DNA . In: Journal of Fish Biology . tape 56 , no. 6 , 2000, pp. 1509–1538 , doi : 10.1111 / j.1095-8649.2000.tb02161.x .