Signal crayfish

Taxobox

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image_width = 200px
image_caption =
name = Signal crayfish
status = LR/lc
regnum = Animalia
phylum = Arthropoda
subphylum = Crustacea
classis = Malacostraca
ordo = Decapoda
superfamilia = Astacoidea
familia = Astacidae
genus = "Pacifastacus"
species = "P. leniusculus"
binomial = "Pacifastacus leniusculus"
binomial_authority = (Dana, 1852)

The signal crayfish, "Pacifastacus leniusculus", is an American crayfish indigenous to the western United States.cite web |url=http://www.american.edu/TED/images3/crwmap.gif
title=Map of crayfish distribution in USA ] Members of this species are up to 15 cm in length.cite web |url=http://www.wbrc.org.uk/WorcRecd/Vol1Iss2/crayFish.htm |title=Crayfish in Worcestershire ] They are bluish-brown to reddish-brown in color with robust large smooth claws. They have a white patch near the claw hinge. Like all crayfish, they are solitary animals and are omnivorous, although their diet is mainly vegetarian they will eat anything from decaying roots and leaves to meat, including crayfish smaller than themselves.cite web |url=http://www.dlc.fi/~marianna/gourmet/crayfish.htm
title=Nordic Recipe Archive Glossary: Crayfish]

Due to the crayfish plague that ravaged European crayfish stocks and has almost exterminated the noble crayfish "Astacus astacus", the Swedish biologist Gunnar Svärdson went to the US to search for a crayfish that could replace the native European crayfish. He found the signal crayfish and started to introduce it into Swedish rivers and lakes. This was the beginning of the introduction of this crayfish not only to various European countries but also to Japan.It was Svärdson who named the signal crayfish. He observed how they were in the habit of waving their claws and thought that the white patches made them look like train dispatchers signaling to an engineer.

Unfortunately, this crayfish has been carelessly introduced to various countries without considering the fact that it carries the crayfish plague, and thus causes the eventual extermination of native crayfish. This was the case both in Great Britain and in Japan.

=External links=
*cite web |url=http://www.vega.org.uk/video/programme/58 |title=Invasion of the Plague Carriers |format=RealVideo |publisher=The Vega Science Trust |year=2002
* [http://news.bbc.co.uk/2/hi/uk_news/scotland/south_of_scotland/7564004.stm 'Kill Crayfish on sight' appeal] BBC News 2008-08-15

References

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IUCN 2007. 2007 IUCN Red List of Threatened Species. http://www.iucnredlist.org. Downloaded on 14 October 2007.