Ayu 1304167 220677658 2008-06-21T01:03:46Z 218.160.108.37 {{otheruses}} {{Taxobox | name = Ayu, Sweetfish | image = Sweetfish, Plecoglossus altivelis.jpg | image_width = 260px | status = NE | status_system = iucn3.1 | regnum = [[Animal]]ia | phylum = [[Chordata]] | superclassis = [[Osteichthyes]] | classis = [[Actinopterygii]] | subclassis = [[Neopterygii]] | infraclassis = [[Teleostei]] | superordo = [[Protacanthopterygii]] | ordo = [[Osmeriformes]] | subordo = [[Osmeroidei]] | superfamilia = [[Osmeroidea]] | familia = '''Plecoglossidae''' | familia_authority = | genus = '''''Plecoglossus''''' | genus_authority = [[Coenraad Jacob Temminck|Temminck]] & [[Hermann Schlegel|Schlegel]], [[1846]]{{Verify source|date=January 2008}}<!-- see at binomial_authority --> | species = '''''P. altivelis''''' | binomial = ''Plecoglossus altivelis'' | binomial_authority = (Temminck & Schlegel, 1846){{Verify source|date=January 2008}}<!-- was it really placed in another genuf first and revised to a monotypic genus less rhan 12 months later by the same authors? --> }} The '''ayu''' (アユ, 鮎),(香魚) or '''sweetfish''', '''''Plecoglossus altivelis''''', is an [[fish migration|amphidromous]] [[fish]], the only [[species]] in the [[genus]] '''''Plecoglossus''''' and in [[family (biology)|family]] '''Plecoglossidae'''. It is a relative of the [[smelts]] and is placed in the [[order (biology)|order]] [[Osmeriformes]]. Native to the [[Palearctic]] [[ecozone]], it occurs in rivers, lakes, and coastal waters of western [[Hokkaidō]] in [[Japan]] southward to the [[Korea]]n Peninsula, [[China]], and [[Taiwan]]. The name "sweetfish" is due to the sweetness of its flesh. In reference to its typical one-year life span, it is also known as ''nen-gyo'' ("year-fish"). The ayu is [[Gunma Prefecture]]'s prefectural fish. ==Systematics== The '''Ryūkyū ayu''' ('''''Plecoglossus altivelis ryukyuensis''''') is a [[subspecies]] of ayu, [[endemic (ecology)|endemic]] to the [[Ryukyu Islands]]: it is much smaller, with a maximum [[total length]] of only about 14 cm (5.5 in). [[IUCN]] classifies the Ryūkyū ayu as [[Conservation status|Endangered]] on the basis of declining and highly fluctuating population and limited and declining range and habitat, but cautions that the status is in need of reassessment.<ref>WCMC (1996)</ref> The [[mitochondrial control region]], usually held to be [[Hypervariable region|hypervariable]] and [[evolution|evolving]] rapidly, is peculiar in the ayu. For reasons unknown, the Ryūkyū population's control region differs from that of others far less than for example [[genes]] encoding for [[protein]]s. A consequence of this fact is that control region [[DNA sequence]]s, commonly used in molecular [[phylogenetics]], provide unreliable data for the ayu. In addition, identification of ayu to [[subspecies]] cannot be accurately performed using control region sequence data.<ref>Takeshima ''et al.'' (2005)</ref> ==Ecology and uses== [[Image:Ayu no Shioyaki.jpg|left|thumb|200px|''Ayu no sio yaki'' 鮎の塩焼き<br/>(Ayu grilled with salt)]] [[Image:Charcoal broiled Ayu.JPG|left|thumb|200px|Ayu being grilled with salt in Japan]] An [[omnivore]], the ayu feeds on [[alga]]e, [[crustacean]]s, [[insect]]s, [[sea sponge|sponge]]s, and [[worm]]s. They are also very territorial animals. The adults ascend from coastal waters into the lower reaches of rivers to spawn in the spring. The [[larva]]e descend to the sea immediately on hatching and winter there before returning to fresh water again in the spring. Most but not all individuals die after their first spawning. Ayu is an edible fish, mostly consumed in [[East Asia]]. Its flesh has a distinctive, sweet flavour with "melon and cucumber aromas".<ref>Gadsby (2004)</ref> It is consequently highly prized as a food fish. The main methods for obtaining ayu are by means of [[fly fishing]], by using a [[trap]], and by fishing with a decoy which is known as ''ayu-no-tomozuri'' in Japan. The decoy is a living ayu placed on a hook, which swims when immersed into water. It provokes the territorial behavior of other ayu, which assault the "intruder" and get caught. This method has been criticized for its cruelty towards the animal. Japanese [[fishing|angler]]s also catch it a traditional method, [[cormorant fishing]] (鵜飼 ''ukai''). On the [[Cormorant Fishing on the Nagara River|Nagara River]] where [[Japanese Cormorant]]s (''Phalacrocorax capillatus'') are used by the fishermen, the fishing season draws visitors from all over the world. The Japanese Cormorants, known in Japanese as ''umi-u'' (ウミウ, "sea-cormorant"), are domesticated birds trained for this purpose. The birds catch the ayu, store it in their [[crop]], and deliver it to the fishermen.<ref>[http://www.gifu-rc.jp/ukai/u_main.html Cormorant Fishing "UKAI"]. Version of May, 2001. Retrieved 2008-JAN-30.</ref> Ayu is also fished commercially in large numbers, and captive juveniles are raised in [[aquaculture]] before being released into rivers for sport fishing. <br clear = "left" /> ==Footnotes== {{Reflist}} ==References== {{commonscat}} * {{FishBase_family|family=Plecoglossidae|year=2004|month=October}} * {{FishBase_genus|genus=Plecoglossus|year=2004|month=October}} * {{FishBase_species_alt|taxon=Plecoglossus altivelis altivelis|ID=251|year=2004|month=October}} * {{FishBase_species_alt|taxon=Plecoglossus altivelis ryukyuensis|ID=26478|year=2004|month=October}} * {{ITIS|ID=162027|taxon=Plecoglossus altivelis|year=2004|date=20 December}} <!-- * {{aut|Akimichi, Tomoya}} (2004): "[http://www.kikkoman.com/forum/010/ff010.html Queen of Freshwater Streams]". ''Kikkoman Soy Sauce Food Forum.'' Accessed on [[21 December]] [[2004]]. [this is redirect now] --> * {{aut|Gadsby, Patricia}} (2004): The Chemistry of Fish. ''[[Discover Magazine]]'' November 2004: 50-57. [http://discovermagazine.com/2004/nov/chemistry-of-fish HTML fulltext] * {{aut|Takeshima, Hirohiko; Iguchi, Kei-ichiro & Nishida, Mutsumi}} (2005): Unexpected Ceiling of Genetic Differentiation in the Control Region of the Mitochondrial DNA between Different Subspecies of the Ayu ''Plecoglossus altivelis''. ''[[Zoological Science|Zool. Sci.]]'' '''22'''(4): 401–410. <small>{{doi|10.2108/zsj.22.401}}</small> (HTML abstract) * {{IUCN2006|assessors={{aut|[[World Conservation Monitoring Centre]] (WCMC)}}|year=1996|id=17595|title=Plecoglossus altivelis'' ssp. ''ryukyuensis|downloaded=31 January 2008}} [[Category:Plecoglossidae]] [[Category:Endangered species]] [[lt:Japoninės stintos]] [[ja:アユ]] [[fi:Aju]] [[th:ปลาอายุ]] [[zh:香魚]]