The Biwa trout (''Oncorhynchus rhodurus'') is an

anadromous Fish migration is mass relocation by fish from one area or body of water to another. Many types of fish migrate on a regular basis, on time scales ranging from daily to annually or longer, and over distances ranging from a few metres to thousan ...

salmonid Salmonidae is a family of ray-finned fish that constitutes the only currently extant family in the order Salmoniformes . It includes salmon (both Atlantic and Pacific species), trout (both ocean-going and landlocked), chars, freshwater whitefis ...

fish of the genus ''

Oncorhynchus ''Oncorhynchus'' is a genus of fish in the family Salmonidae; it contains the Pacific salmon and Pacific trout. The name of the genus is derived from the Greek ὄγκος (ónkos, “lump, bend”) + ῥύγχος (rhúnkhos, “snout”), in r ...

'', endemic to Lake Biwa in Shiga Prefecture,

Japan Japan ( ja, 日本, or , and formally , ''Nihonkoku'') is an island country in East Asia. It is situated in the northwest Pacific Ocean, and is bordered on the west by the Sea of Japan, while extending from the Sea of Okhotsk in the north ...

, but also introduced to

Lake Ashi , also referred to as Hakone Lake or Ashinoko Lake, is a scenic lake in the Hakone area of Kanagawa Prefecture in Honshū, Japan. It is a crater lake that lies along the southwest wall of the caldera of Mount Hakone, a complex volcano that last ...

and Lake Chūzenji. While called trout, the fish is most closely related to the

masu salmon The masu salmon (''Oncorhynchus masou''), also known as masu ( ja, マス, , trout) or in Japan, is a species of salmon belonging to the genus ''Oncorhynchus'', found in the North Pacific along Northeast/East Asian coasts from the Russian Far Eas ...

(''Oncorhynchus masou'') of the western Pacific, and is most often considered a subspecies of it, ''Oncorhynchus masou rhodurus''. ''rhodurus, Oncorhynchus''
In: W. Eschmeyer: Catalog of Fishes Online Database. California Academy of Sciences. Downloaded 16 Feb 2015 Biwa trout is found only in the waters of northern Lake Biwa, and feeds on plankton, freshwater prawns, aquatic insects, worms, ''

ayu Ayu or AYU may refer to: * Ayu (given name) * Ayu sweetfish (''Plecoglossus altivelis''), a species of smelt * ''Ayu'', a local name for the African manatee * Ayu (singer) or Ayumi Hamasaki, Japanese singer * Ayu Islands, a small archipelago in I ...

'' and other small fishes, and sometimes small mammals. Adult Biwa trout usually range from in length and in weight, although large specimens can be up to long and in weight.

Use as food

Biwa trout represents a unique food fish for the Shiga Prefecture. Biwa trout and its caviar are considered a delicacy. Usual ways to prepare the trout is as sashimi, by

grilling Grilling is a form of cooking that involves dry heat applied to the surface of food, commonly from above, below or from the side. Grilling usually involves a significant amount of direct, radiant heat, and tends to be used for cooking meat a ...

with salt, in meuniere, or by

smoking Smoking is a practice in which a substance is burned and the resulting smoke is typically breathed in to be tasted and absorbed into the bloodstream. Most commonly, the substance used is the dried leaves of the tobacco plant, which have bee ...

, deep-frying or simmering, ''etc''. The fish has a reputation as being very difficult to catch by angling.

References

External links

*Yoshikazu Fujiok
Profile of Biwamasu
Trout and Seasons of The Mountain Village. www.hi-ho.ne.jp

* ttps://web.archive.org/web/20061201045002/http://members.aol.com/user231961/biwa.htm Fishing info. of Biwa trout (Japanese - at Archive.org) Oncorhynchus Endemic fauna of Japan Freshwater fish of Japan Fish described in 1925 {{Salmoniformes-stub