Japan country information

Common names: Ayu, Koayu, Ryukyu-ayu
Occurrence: native
Salinity: freshwater
Abundance: abundant (always seen in some numbers) | Ref: Pastene, L.A., K. Numachi and K. Tsukamoto, 1991
Importance: highly commercial | Ref:
Aquaculture: commercial | Ref:
Regulations: | Ref:
Uses: gamefish: yes;
Comments: Occurs in western Hokkaido southward (Ref. 559, 11230). Found in Hokkaido's Ishikari river and the southern tributaries and river mouths (Ref. 12218); Nansei-shoto (Ref. 34989); Futatsukawa Creek, Fukuoka Prefecture (Ref. 37350); and Himi region from a habitat study conducted in Toyama Bay (Ref. 58909). Highly esteemed food and game fish. Cultured throughout western Japan in sea cages. Recorded as having been or being farmed in rice fields (Ref. 119549). Category in the 2005 Red Data Book of Shiga Prefecture: important distribution (Ref. 79825). Also Ref. 45563, 96271.
National Checklist:
Country Information: https://www.cia.gov/library/publications/resources/the-world-factbook/geos/ja.html
National Fisheries Authority: http://www.maff.go.jp/eindex.html
Occurrences: Occurrences Point map
Main Ref: Masuda, H., K. Amaoka, C. Araga, T. Uyeno and T. Yoshino, 1984
National Database:

Common names from other countries

Ayu, Айю, سمك ليِّن أيو, ... more

Classification / Names ຊື່ສາມັນ | ຄຳສັບຄ້າຍຄືກັນ | Catalog of Fishes(ຕະກຸນ, ຊະນິດ) | ITIS | CoL | WoRMS | Cloffa

> Osmeriformes (Freshwater smelts) > Plecoglossidae (Ayu fish)
Etymology: Plecoglossus: Greek, pleko, plekein = to fold + Greek, glossa = tongue (Ref. 45335).
More on authors: Temminck & Schlegel.

Issue
All subspecies of Plecoglossus altivelis (Temminck & Schlegel, 1846) are synonymised under the species in Eschmeyer (CofF ver. Jul. 2010: Ref. 84883). Please send references, or more studies are needed.

Environment: milieu / climate zone / depth range / distribution range ນິເວດວິທະຍາ

ສັດທະເລ; ນ້ຳຈືດ; ນ້ຳກ່ອຍ ອາໄສຢູ່ໃກ້ໜ້າດິນໃຕ້ພື້ນທ້ອງນ້ຳ; ປາທີ່ມີການເຄື່ອນຍ້າຍຈາກທະເລໄປຫານ້ຳຈືດ ແລະນ້ຳຈືດຫາທະເລ (Ref. 51243); ລະດັບຄວາມເລິກ 10 - ? m. Subtropical; 44°N - 23°N

ການແຜ່ກະຈາຍ ປະເທດ | ເຂດ FAO | ລະບົບນິເວດ | ການປະກົດຕົວ | Point map | ການແນະນຳ | Faunafri

Northwest Pacific: western Hokkaido in Japan southward to the Korean Peninsula, Taiwan and China.

Length at first maturity / ຂະໜາດ / ນ້ຳໜັກ / Age

Maturity: L_m 27.5, range 30 - 40 cm
Max length : 70.0 cm TL ຕົວຜູ້/ບໍ່ມີເພດ; (Ref. 12218); common length : 15.0 cm SL ຕົວຜູ້/ບໍ່ມີເພດ; (Ref. 35840); ອາຍຸສູງສຸດທີ່ເຄຍລາຍງານມາ: 3.00 ປີ (Ref. 12218)

Short description ຕົວທີ່ໃຊ້ໃນການຈຳແນກຊະນິດ | ສະລີລະວິທະຍາ | ການວັດແທກຮູບຮ່າງລັກສະນະພາຍນອກຂອງດິນ,ສັດ,ປາ…

ຄີ (ໜາມ)ແຂງຢູ່ຫຼັງປາ (ທັງໝົດ) : 0; ຄີຫຼັງຂອງປາ (ຄີອ່ອນ) (ທັງໝົດ) : 10 - 11; ຄີກົ້ນຂອງປາ: 14 - 15; ສັດທີ່ມີກະດູກສັນຫຼັງ: 60 - 63. Pyloric caeca 350-400.

Typical amphidromous fish; appears in near shore from late autumn to spring (Ref. 11230). Found in lakes and rivers, preferring clean river water and can be found the entire river long, from the head to the mouth (Ref. 12218). Ascends the river during March when the temperature is around 10°C (Ref. 12218). Adults spawn in the spring, in the lower reaches of rivers. After spawning, some adults die while others return to the sea. Larvae enter the sea immediately after hatching and remain there during winter, feeding on plankton. In springtime, the young (5-7 cm TL) move upstream to the middle reaches of rivers to feed on algae. Fish (about 6-9 cm) start schooling at the river mouth and are insectivores and eat algae off small pebbles (Ref. 12218); this is assisted by small leaf-like teeth which are loosely attached to the jaw with two ligaments (Ref. 45181). Those that are ready to spawn (about 20 cm TL) move downstream to the lower reaches of the river. Spawning adults from the sea migrate upstream to the lower reaches as well. Some fish spawn two or three years in succession, others only once (Ref. 9987 & 559). River forms live usually only one year whereas lake forms can live two or three years (Ref. 12218). Reaches maturity at 30-40 cm (Ref. 12218). Highly esteemed food fish. Marketed fresh and consumed fresh, fried and broiled (Ref. 9987).

Life cycle and mating behavior Maturities | ການສືບພັນ | Spawnings | Egg(s) | Fecundities | ຕົວອ່ອນ

During spawning some fish go up the river and some fish spawn on the river shoreline above pebbles. Spawns at night and excavates a 10cm (diameter or depth?) pit. Eggs are around 1 mm in size and adhere to the sand or pebbles for 14 to 20 days before hatching. This fish is semelparous and releases eggs many times over a short period each time releasing ~10,000 eggs. Sometimes females that want to spawn but cannot, save their strength, and go to a deep stagnant pool. These females wait until spring before going up the river with young fish. After hatching, the larvae are 6 mm and flow with the water current eating plankton. Juvenile fish will come again to the river in spring. These live in schools. When schools of Plecoglossus altivelis return to their river they guard their territory and eat food (Ref. 12218). Reproductive mode varies between semelparity and iteroparity. Large females spawn once, while smaller females spawn twice during a two-week interval (Ref. 76896).

Main reference Upload your references | ເອກະສານອ້າງອີງ | ຜູ້ປະສານງານ | ຜູ້ຮ່ວມມື

Masuda, H., K. Amaoka, C. Araga, T. Uyeno and T. Yoshino, 1984. The fishes of the Japanese Archipelago. Vol. 1. Tokai University Press, Tokyo, Japan. 437 p. (text). (Ref. 559)

IUCN Red List Status (Ref. 130435)

Data deficient (DD) ; Date assessed: 03 September 2010

CITES (Ref. 128078)

Not Evaluated

CMS (Ref. 116361)

Not Evaluated

Threat to humans

Harmless

Human uses

ການປະມົງ: ທີ່ມີການຄ້າສູງ; ການລ້ຽງສັດນ້ຳ: ເປັນສີນຄ້າ; ຊະນິດປາທີ່ຖືກນຳໃຊ້ເຂົ້າໃນການຫາເພື່ອເປັນເກມກິລາ: ແມ່ນ

FAO(Aquaculture systems: ຜົນຜະລິດ; ການປະມົງ: ຜົນຜະລິດ, species profile; publication : search) | FishSource | ທະເລອ້ອມຂ້າງພວກເຮົາ

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Summary page | ຈຸດໃດໜຶ່ງທີ່ສະແດງຂໍ້ມູນ | ຊື່ສາມັນ | Photos

ແຫຼ່ງອີນເຕີເນັດ

Estimates based on models

Preferred temperature (Ref. 115969): 13 - 22.6, mean 19.7 (based on 42 cells).

Phylogenetic diversity index (Ref. 82804): PD₅₀ = 1.5000 [Uniqueness, from 0.5 = low to 2.0 = high].

Bayesian length-weight: a=0.00427 (0.00165 - 0.01101), b=3.07 (2.84 - 3.30), in cm Total Length, based on LWR estimates for this (Sub)family-body shape (Ref. 93245).

ຊັ້ນເຂດຮ້ອນ (Ref. 69278): 2.8 ±0.16 se; based on food items.

ຄວາມຢືດຢຸ່ນ (Ref. 120179): ສູງ, ປະຊາກອນຕຳ່ສຸດທີ່ໃຊ້ເວລາສອງໜ້ອຍກວ່າ 15 ເດືອນ (tm=1; tmax=3; Fec=50,000-100,000).

Fishing Vulnerability (Ref. 59153): Moderate to high vulnerability (48 of 100).

Price category (Ref. 80766): Unknown.

Plecoglossus altivelis (Temminck & Schlegel, 1846)