''Silurus biwaensis'', the giant Lake Biwa catfish or ''Biwako-o'namazu'' (ビワコオオナマズ (Japan)), is a large predatory

catfish Catfish (or catfishes; order Siluriformes or Nematognathi) are a diverse group of ray-finned fish. Named for their prominent barbels, which resemble a cat's whiskers, catfish range in size and behavior from the three largest species alive, ...

species endemic to

Lake Biwa is the largest freshwater lake in Japan, located entirely within Shiga Prefecture (west-central Honshu), northeast of the former capital city of Kyoto. Lake Biwa is an ancient lake, over 4 million years old. It is estimated to be the 13th ol ...

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 ...

Description

The giant Lake Biwa catfish is very similar to

wels catfish The wels catfish ( or ; ''Silurus glanis''), also called sheatfish or just wels, is a large species of catfish native to wide areas of central, southern, and eastern Europe, in the basins of the Baltic, Black and Caspian Seas. It has been introd ...

, which it is closely related to. It has an elongated cylindrical body and can reach up to in length and weigh as much as . The top of the body is dark grey to black in colour while the underside is a pale, whitish colour.

Lifecycle

They

prey Predation is a biological interaction where one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not kill the ...

on fish and frogs which live in the lake. ''S. biwaensis'' is the largest predatory fish in

. Using telemetry methods researchers tried to explain the migratory behavior of the species. It was found that the fish are more or less site-faithful and mostly stay close to their spawning grounds. Other studies have shown that the sub-populations of the lake hardly mix.

Relationship to humans

Some fishermen believe that the catfish change their behavior and become very active when an earthquake is imminent.''The Best Earthquake Predictor is a Catfish.''
/ref> In Japanese mythology, a giant catfish named

Namazu In Japanese mythology, the or is a giant underground catfish who causes earthquakes. The creature lives under the islands of Japan and is guarded by the god Takemikazuchi enshrined at Kashima, who restrains the catfish with a stone. When t ...

causes earthquakes as he moves below the earth's surface.

References

{{Taxonbar, from=Q2286409 biwaensis Freshwater fish of Japan Endemic fauna of Japan Fish described in 1961