Temminck & Schlegel, 1846
(Temminck & Schlegel, 1846)
The ayu (アユ, 鮎, 年魚, 香魚?) or sweetfish, Plecoglossus altivelis, is a species of 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 the Palearctic ecozone, it is distributed in the northwestern Pacific Ocean along the coast of Hokkaidō in Japan southward to the Korean Peninsula, China, and Hong Kong. It is amphidromous, moving between marine and freshwater bodies. It can be found in local rivers and lakes. It is an introduced species in Taiwan.
The name "sweetfish" was inspired by the sweetness of its flesh. In reference to its typical one-year lifespan, it is also written as 年魚 ("year-fish"). Some individuals live two to three years. The ayu is the prefectural fish of Gunma Prefecture and Gifu Prefecture.
- 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)
This is a migratory fish. It lives along the coast between autumn and spring. It enters the rivers to breed, and while some die afterwards, many return to the ocean. Larvae are carried downriver to the sea, where they grow and develop. Some populations can be found in lakes, where they remain their entire lives. They are also stocked in reservoirs.
Ayu is an edible fish, mostly consumed in East Asia. Its flesh has a distinctive, sweet flavour with "melon and cucumber aromas". It is consequently highly prized as a food fish. 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.
Japanese fishers also catch it using a traditional method, cormorant fishing (鵜飼 ukai). On the Nagara River where Japanese cormorants (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 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.
- Huckstorf, V. 2012. Plecoglossus altivelis. The IUCN Red List of Threatened Species. Downloaded on 18 February 2016.
- Queen of Freshwater Streams. Food Forum. Kikkoman Global Website.
- Symbols of Gifu Prefecture. Gifu Prefectural Government.
- Froese, R. and D. Pauly, Editors. Plecoglossus. FishBase. 2015.
- Shan, X., Wu, Y., & Kang, B. (2005). 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.
- Froese, R. and D. Pauly, Editors. Plecoglossus altivelis altivelis. FishBase. 2015.
- "Rock Fishing in Tokushima, Japan". USA Today.
- Gadsby, P. The chemistry of fish. Discover Magazine 25 November 2004.
- Waldman, J. (2005). 100 Weird Ways to Catch Fish (1st ed.). Mechanicsburg, PA: Stackpole Books. pp. 6–7. ISBN 0811731790.
- Cormorant-Fishing on the Nagara River. Gifu Rotary Club.
- No. 2: Ayu fish. Hiroko's Kitchen. 10 August 2010.
- 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. Zool. Sci. 22(4): 401–410. doi:10.2108/zsj.22.401 (HTML abstract)
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- Plecoglossus altivelis. Integrated Taxonomic Information System (ITIS).