Kaluga-Hausen
| Kaluga-Hausen | ||||||||||||
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Prepared Kaluga houses in a museum |
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| Scientific name | ||||||||||||
| Huso dauricus | ||||||||||||
| ( Georgi , 1775) |
The Kaluga-Hausen or Siberian Hausen ( Huso dauricus ) is one of two species of the genus of Hausen ( Huso ) from the family of sturgeon (Acipenseridae). It is endemic to the Amur in Northeast Asia on the border of Russia and China . Like the European Hausen ( Huso huso ), the species is one of the largest fish found in freshwater and is now threatened with extinction.
features
The Kaluga-Hausen has the typical elongated shape of the sturgeon with five rows of bone shields and heterocerker caudal fin . The mouth is crescent-shaped like in European houses and is so wide that it extends to the edge of the muzzle. In contrast to that of the sturgeon ( Acipenser ), it opens towards the front and the four barbels sitting in front of it are flattened at the side, but unlike the European Hausen, they are not fringed. The gill membranes on both sides are connected and free on the abdomen. The gill trap has 16 to 23 thorns. The highest point of the back is on the first back plate and therefore further forward than on the European Hausen. The 10 to 16 back shields are rounded (?), Behind the 43 to 57-rayed dorsal fin are 1–3 small shields. There are 32 to 46 shields in the side row and 7 to 13 shields in the belly row. There are 2 to 6 shields between the anus and the 26- to 35-rayed anal fin and another 1 to 3 behind the anal fin.
size
Kaluga houses reach sexual maturity with a length of 170 to 190 centimeters and usually reach a length of 180 to 230 centimeters. Depending on the author, the maximum size is between four and a half and 5.6 meters with a weight of up to a ton. The largest Kaluga captured so far was captured on the Amur in 1996, weighed 250 kilograms and was 3.50 meters long. He can reach an age of up to 80 years. In May 2012 Spiegel.de reported on a catch of a Kaluga weighing 617 kilograms. The fish lady is to provide for offspring in a breeding station in the future.
Occurrence
The species inhabits the more than 4,000 kilometers long Amur and its tributaries and can colonize all major rivers and lakes from the highlands to the mouth. Young animals also penetrate into coastal areas in the summer. There are four populations that populate the estuary area, the lower Amur, the upper Amur and the tributaries Seja and Bureja . The most common catches of Kaluga-Hausen are reported from the middle reaches of the Amur, where Chinese and Russian fishermen have their fishing grounds together. Furthermore, they occur in the tributaries Shilka , Onon , Argun , Nerch , Sungari , Nonni , Ussuri and Neijiang, partly also in Lake Khanka or Lake Orel above Nikolaewsk. Young animals are found in the coastal waters of the Sea of Okhotsk , in the northeastern part of the Tatar Strait and in the Sea of Japan , near the islands of Hokkaidō and Honshū .
Way of life
Kaluga houses are migrating predatory fish. Together with typical benthic fish species such as Acipenser schrenckii , Iksookimia longicorpa , I. koreensis , I. hugowolfeldi , Cobitis melanoleuca melanoleuca and Iksookimia pumila, they inhabit the bottom of the water. In the case of the best-studied population in the mouth area, two morphs can be distinguished. The more common with 75 to 80% of individuals morph keeps all year in fresh water, while the other morphs in late June to early July in the brackish waters of the estuary and the adjacent seas areas with salinities immigrates 12-16 ‰. Young animals can then be caught in the Sea of Okhotsk and the Sea of Japan around Sakhalin , Hokkaidō and Honshū. In autumn, when the salinity rises, they return to the river. If they do not succeed in this due to the weather and the water reaches a salinity of 20 to 30 ‰ and temperatures below 0 ° C, they die.
Their number was estimated in the 1980s by Krykhtin and Svirskii at 70,000 individuals in the coastal population (estuary population) and 30,000 individuals in the Amur morph. The food depends on the age of the animals, although the animals do not eat in winter or sexually mature animals during the spawning season . Young animals mainly feed on invertebrates in the first year . Later they catch juvenile fish of pelagic species such as the ketal salmon ( Oncorhynchus keta ), while older animals from around 3 to 4 years of age mainly eat fully grown fish. Even cannibalism is common. A certain aggressiveness is ascribed to Kaluga sturgeon. There are reports that they overturned fishing boats and harassed fishermen who had fallen into the water. However, a specific attack on humans has never been proven.
Danger
Residues from oil production, phenol and the introduction of mineral fertilizers have negatively influenced the water quality of the Amur. The introduction of mercury and the accumulation of heavy metal on the bottom of the water, especially from the time of Soviet industrialization, impaired the population of the Kaluga sturgeon. Due to its roe, the populations in the past have been brought to the brink of extinction. In the meantime, fishing is strictly prohibited in many places. While its stock was still considered rare in 1986, it was classified as endangered in 1996. The population decreased by 80% from the 19th century to 1992. The Kaluga-Hausen is not yet completely protected everywhere. In the Chinese Heilongjiang Province , protective measures such as catch restrictions, closed seasons and protected areas were adopted as early as the 1950s. These measures were renewed in 1982. The minimum size is 200 centimeters and a weight of 65 kilograms. Undersized Kaluga houses have to be reset. Catching is completely prohibited from mid-June to mid-July. The 1,270 kilometer stretch of water from Fuyan to Heihe has been declared a protection zone.
Economical meaning
The Kaluga-Hausen is of economic importance for the production of caviar . While the official catch statistics of Russia in 1881 recorded 595 tons of Kaluga houses, the number fell to 61 tons in 1948 with a slight increase to 89 tons in 1996. In 1998, China exported 4,481 kilograms and Russia 2,758 kilograms of caviar, mainly to the UNITED STATES. The main customer countries are Japan , the Federal Republic of Germany , the USA and the United Arab Emirates .
Notes and individual references
- ^ A b c Minister of Supply and Services Canada (Ed.): CITES Identification Guide - Sturgeons and Paddlefish: Guide to the Identification of Sturgeon and Paddlefish Species Controlled under the Convention on International Trade in Endangered Species of Wild Fauna and Flora . Wildlife Enforcement and Intelligence Division, Environment Canada, 2001, ISBN 0-660-61641-6 (English, French, Spanish, full text [PDF]).
- ↑ a b Kaluga-Hausen on Fishbase.org (English)
- ↑ Fishing World Records Huso dauricus
- ↑ a b c d e http://www.cites.org/eng/com/ac/16/16-7-2a8.pdf Huso dauricus Georgi, 1775, Kaluga, Great Siberian Sturgeon
- ↑ Scary river dwellers: fishermen catch 600 kilos of sturgeon on Spiegel Online (May 18, 2012) (video report)
- ↑ a b c Mikhail L. Krykhtin, Victor G. Svirskii: Endemic sturgeons of the Amur River: kaluga, Huso dauricus, and Amur sturgeon, Acipenser schrenckii . In: Environmental Biology of Fishes . tape 48 , 1997, pp. 231-239 (English).
- ↑ a b c https://apiv3.iucnredlist.org/api/v3/taxonredirect/10268
- ↑ LS Berg: Freshwater fishes of the USSR and adjacent countries, 1962, Vol. 1, 4th edition, Israel Program for Scientific Translations Ltd, Jerusalem. (Russian version published 1948)
- ↑ of Life, Amur River Demersal Habitat ( page no longer available , search in web archives ) Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice.
- ↑ of Life: Huso dauricus, River Beluga ( page no longer available , search in web archives ) Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice.
- ↑ also mercury sulphide from mining processes and inadequate wastewater treatment
- ^ "The Heilongjiang Ordinance on the Protection and Propagation of Fisheries Resources"
- ^ "Protocol on Fisheries Resources Conservation, Regulation and Multiplication in Border Areas of Heilong (Amur) River and Wusuli River (Ussuri) of The People's Republic of China and the Russian Federation"
literature
- MV Sytova, HN Harenko, VA Belyaev and AP Shmigirilov: The analysis of quantitative and weight parameters of sturgeons spawning groups at Amur river basin, Vopr. Rybolovstva (Problems of fisheries), 2004, 5 (3), pp. 470-481
Web links
- Kaluga-Hausen on Fishbase.org (English)
- Huso dauricus in the endangered Red List species the IUCN 2011. Posted by: G. Ruban, W. Qiwei, 2010. Retrieved on 18 May 2012 found.