Silurus biwaensis
Description
File:Silurus biwaensis Stuffed specimen.jpg
The giant Lake Biwa catfish is very similar to wels catfish, which it is closely related to. It has an elongated cylindrical body and can reach up to {{convert|1.18|m|abbr=on}} in length and weigh as much as {{convert|17|kg|abbr=on}}.{{FishBase |genus=Silurus |species=biwaensis |month=April |year=2013}} The top of the body is dark grey to black in colour while the underside is a pale, whitish colour.
Life cycle
They prey on fish and frogs which live in the lake. S. biwaensis is the largest predatory fish in Lake Biwa.{{cite web|title=Lake Biwa Facts|url=http://www.lbm.go.jp/english/facts/|publisher=Lake Biwa Museum|accessdate=4 March 2013}} 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.{{cite journal|last=Takai|first=N.|author2=Sakamoto, W. |author3=Maehata, M. |author4=Arai, N. |author5=Kitagawa, T. |author6= Mitsunaga, Y. |title=Settlement characteristics and habitats use of Lake Biwa catfish Silurus biwaensis measured by ultrasonic telemetry|journal=Fisheries Science|date=1997|volume=63|issue=2|pages=181–187|doi=10.2331/fishsci.63.181|url=http://www.mendeley.com/research/settlement-characteristics-habitats-lake-biwa-catfish-silurus-biwaensis-measured-ultrasonic-telemetry/|accessdate=4 March 2013|issn=0919-9268|doi-access=free|bibcode=1997FisSc..63..181T }} Other studies have shown that the sub-populations of the lake hardly mix.{{cite journal|last=Takai|first=Noriyuki|author2=Sakamoto, Wataru |title=Identification of local populations of Lake Biwa catfish in Japan on the basis of δ13C and δ15N analyses|journal=Canadian Journal of Zoology|date=1 August 1999|volume=77|issue=2|pages=258–266|doi=10.1139/z98-210}}
Relationship to humans
Some fishermen believe that the catfish change their behavior and become very active when an earthquake is imminent.[https://archive.today/20120729092701/http://therockyriver.com/the-best-earthquake-predictor-is-a-catfish/ The Best Earthquake Predictor is a Catfish.] In Japanese mythology, a giant catfish named Namazu causes earthquakes as he moves below the Earth's surface.{{cite book|last=Ashkenazi|first=Michael|title=Handbook of Japanese Mythology|url=https://archive.org/details/handbookofjapane0000ashk|url-access=registration|year=2003|publisher=ABC-CLIO|location=Santa Barbara (Calif.)|isbn=1576074676|page=[https://archive.org/details/handbookofjapane0000ashk/page/220 220]}}
References
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Category:Freshwater fish of Japan
Category:Endemic fish of Japan