Surf Wiki
Save to docs
geography/japan

From Surf Wiki (app.surf) — the open knowledge base

Ayu sweetfish

Species of fish

Ayu sweetfish
Summary

Species of fish

| Salmo altivelis | (Temminck & Schlegel, 1846) | Plecoglossus altivelis altivelis | (Temminck & Schlegel, 1846) | Plecoglossus altivelis ryukyuensis | (Nishida, 1988) | Plecoglossus ryukyuensis | (Nishida, 1988) | Plecoglossus altivelis chinensis | (Wu & Shan, 2005) The ayu sweetfish (Plecoglossus altivelis), ayu or sweetfish, is a species of bony fish. It is the only species in the genus Plecoglossus and family Plecoglossidae. It is a relative of the smelts and other fish in the order Osmeriformes.

Native to East Asia, it is distributed in the northwestern Pacific Ocean along the coast of Hokkaidō in Japan southward to the Korean Peninsula, China, Hong Kong and northern Vietnam. It is amphidromous, moving between coastal marine waters and freshwater lakes and rivers. A few landlocked populations also exist in lakes in Japan such as Lake Biwa. Original wild populations in Taiwan became extinct in 1968 due to pollution and present extant populations were reintroduced from Japan in the 1990s.

The name "sweetfish" was inspired by the sweetness of its flesh. In reference to its typical one-year lifespan, it is also written as ("year-fish"). Some individuals live two to three years. The ayu is the prefectural fish of Gunma Prefecture and Gifu Prefecture.

Subspecies

Two to three subspecies are recognized by some authors. Others do not distinguish the subtaxa.

Subspecies include:

  • P. a. altivelis (Temminck & Schlegel, 1846) (ayu, sweetfish)
  • P. a. chinensis Y. F. Wu & X. J. Shan, 2005 (Chinese ayu)
  • P. a. ryukyuensis M. Nishida, 1988 (Ryukyu ayu-fish) – endangered

Biology

A school of ayu

An omnivore, the ayu feeds on algae, crustaceans, insects, sponges, and worms. It feeds on algae that accumulates on the rocks, scraping it off the rocks with their saw-shaped teeth. Adults typically maintain a feeding territory, but the form restricted to lakes and associated streams is schooling.[[File:Plecoglossus altivelis altivelis hami-ato1.jpg|thumb|Scrape marks left by ayu feeding on algae when the rock was submerged|left]]Most populations of this species are amphidromous and breed in the lower part of rivers during the autumn, laying their eggs in small pits they dig in the gravel. The eggs hatch shortly after and the larvae are carried downriver to the sea. They overwinter in coastal regions, staying there until the spring where the young fish typically are about 6 cm long and move back to the rivers. Here they reach 15 - by the summer. In Japan, some populations live their entire life in freshwater, only moving between lakes and the associated streams where they breed. These have a more variable migration pattern, moving upstream from the lakes in the spring, summer or autumn. Although their larvae mostly stay within freshwater, some are carried downstream with the current to the sea and become part of the amphidromous populations. The freshwater-restricted populations typically reach an age of two or three years. During the breeding season the amphidromous and freshwater-restricted forms may occur together. Ayu are also stocked in reservoirs.

[[Lake Biwa]] ayu

Although there are reports of ayu up to 70 cm long, The form restricted to freshwater is considerably smaller than the amphidromous form. This is caused by differences in the availability of food.

Human uses

website=Food and Agriculture Organization of the United Nations (FAO)}}</ref>

The ayu is highly prized for its flavour, mostly consumed in East Asia. Its flesh is distinctively sweet, with "melon and cucumber aromas". The main methods for obtaining ayu are by means of fly fishing, by using a fish 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.

Ayu being grilled with salt in Japan; note the wave-like &quot;swimming&quot; shape of the skewered fish

The ayu is also caught by cormorant fishing. The practice on the Nagara River, where Japanese cormorants (Phalacrocorax capillatus) are used, 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 bird catches the ayu, stores it in its crop, and delivers it to the fishermen.

Ayu is also fished commercially, and captive juveniles are raised in aquaculture before being released into rivers for sport fishing.

In Japanese cuisine, a common method of preparing ayu (among other small fish) is to fold their bodies in a wave-like "swimming" shape, then skewer. The fish is then grilled with salt over charcoal to preserve the natural flavor of the fish.

References

References

  1. Huckstorf, V.. (2012). "''Plecoglossus altivelis''".
  2. TVBS. "盤點台灣淡水魚 原生種香魚已滅絕│TVBS新聞網".
  3. [http://www.kikkoman.com/foodforum/thejapanesetablebackissues/11.shtml Queen of Freshwater Streams.] {{Webarchive. link. (25 April 2014 Food Forum. Kikkoman Global Website.)
  4. [http://www.pref.gifu.lg.jp/foreign-languages/English/info/gifu/3.html Symbols of Gifu Prefecture.] Gifu Prefectural Government.
  5. Froese, R. and D. Pauly, Editors. [http://www.fishbase.org/identification/SpeciesList.php?genus=Plecoglossus ''Plecoglossus''.] FishBase. 2015.
  6. Shan, X., Wu, Y., & Kang, B. (2005). [http://adsabs.harvard.edu/abs/2005JOUC....4...61S Morphological comparison between Chinese Ayu and Japanese Ayu and establishment of Wu & Shan subsp. nov.] ''Journal of Ocean University of China'' (English Edition), 1(4), 61–66.
  7. Froese, R. and D. Pauly, Editors. [http://www.fishbase.org/summary/SpeciesSummary.php?ID=251&genusname=Plecoglossus&speciesname=altivelis+altivelis ''Plecoglossus altivelis altivelis''.] FishBase. 2015.
  8. World Conservation Monitoring Centre. (1996). "''Plecoglossus altivelis'' ssp. ''ryukyuensis''".
  9. "Rock Fishing in Tokushima, Japan". USA Today.
  10. Hooper, R. (21 September 2005). [http://www.japantimes.co.jp/life/2005/09/21/environment/ayu-sweetfish/#.WKI2fKjcCf0 Ayu sweetfish.] The Japan Times. Retrieved 13 February 2017.
  11. Shirakihara, Yoshids, Nishino, Takao and Sawada (2001). Acoustic evaluation of the vertical distribution of dwarf ayu Plecoglossus altivelis altivelis in Lake Biwa. Fisheries Science 67: 430–435.
  12. Lucas, M., and E. Baras (2001). Migration of Freshwater Fishes, p. 187. Blackwell Science. {{isbn. 0-632-05754-8
  13. Otake and Uchida (1998). Application of Otolith Microchemistry for Distinguishing between Amphidromous and Non-amphidromous Stocked Ayu, Plecoglossus altivelis. Fisheries Science 64(4): 517–521.
  14. They reach maturity by the autumn and move down to the lower part of rivers to breed. Some die after breeding and only live one year, but others return to live in the ocean and may spawn up to three times, each time moving into the lower part of rivers in the autumn.Shimizu, Uchida, Udagawa, Inoue, Sato and Katsura (2007). Multiple spawning and related variations in female reproductive parameters of amphidromous type ayu. Fisheries Science 73(1): 9–18.
  15. a more typical maximum size for the species is about {{convert. 30. cm. ft
  16. The freshwater-restricted ayu of [[Lake Biwa]] that migrate into their spawning streams in the spring can reach up to about {{convert. 15. cm. in. 0 in length, but those that migrate later in the year, primarily in the autumn, only grow to {{convert. 10. cm. in
  17. "Fisheries and Aquaculture - Global Production".
  18. Gadsby, Patricia. (November 25, 2004). "The Chemistry of Fish".
  19. Waldman, J.. (2005). "100 Weird Ways to Catch Fish". Stackpole Books.
  20. [http://www.gifu-rc.jp/ukai/u_main.html Cormorant-Fishing on the Nagara River.] {{Webarchive. link. (19 January 2014 Gifu Rotary Club.)
  21. [http://hirokoskitchen.com/2010/08/no-2ayu-fish/ No. 2: Ayu fish.] Hiroko's Kitchen. 10 August 2010.
Wikipedia Source

This article was imported from Wikipedia and is available under the Creative Commons Attribution-ShareAlike 4.0 License. Content has been adapted to SurfDoc format. Original contributors can be found on the article history page.

fauna-of-hong-kong freshwater-fish-of-japan plecoglossidae fish-of-korea taxa-named-by-coenraad-jacob-temminck taxa-named-by-hermann-schlegel fish-described-in-1846 edible-fish
Want to explore this topic further?

Ask Mako anything about Ayu sweetfish — get instant answers, deeper analysis, and related topics.

Research with Mako

Free with your Surf account

Content sourced from Wikipedia, available under CC BY-SA 4.0.

This content may have been generated or modified by AI. CloudSurf Software LLC is not responsible for the accuracy, completeness, or reliability of AI-generated content. Always verify important information from primary sources.

Report