Editing Signal crayfish (section)

==Description and ecology==
[[File:Kräftklo-1.jpg|thumb|left|A white oval patch at the joint of the fingers of the claw distinguishes this species.]]
Members of this species are typically {{convert|6|-|9|cm|abbr=on}} long, although sizes up to {{convert|16|-|20|cm|sigfig=1|abbr=on}} are possible.<ref name="Nobanis"/> A distinctive white to pale blue-green patch is present near the claw hinge,<ref>{{cite journal|url=http://www.wbrc.org.uk/WorcRecd/Vol1Iss2/crayFish.htm|title=Crayfish in Worcestershire|journal=Worcestershire Record|volume=1|issue=2|year=1997|page=4|author=Mike Averill}}</ref> reminiscent of the white flags that signalmen used for directing trains&mdash;hence the species' common name.

The [[Biological life cycle|lifecycle]] of the signal crayfish is typical for the family [[Astacidae]]. The mating season occurs in the autumn, during which time the female produces around 200 to 400 [[egg (biology)|eggs]]. These are then carried under the female's tail until they are ready to hatch in the following spring.<ref name="Nobanis"/> Upon hatching, the [[juvenile (organism)|juveniles]] undergo three stages of development, passing through (two [[ecdysis|moults]]), before they are able to leave their mother. [[Sexual maturity]] is reached after two to three years, and the [[longevity|lifespan]] can extend up to 20 years.<ref name="Nobanis"/>

The signal crayfish is an [[omnivore]], with a diet primarily consisting of [[detritus]].<ref>{{cite journal |author=Carin A. Bondar|author2=K. Bottriell|author3=K. Zeron|author4=John S. Richardson|year=2005|title=Does trophic position of the omnivorous signal crayfish (''Pacifastacus leniusculus'') in a stream food web vary with life history stage or density? |journal=[[Canadian Journal of Fisheries and Aquatic Sciences]]|volume=62|issue=11|pages=2632–2639|doi=10.1139/F05-167|bibcode=2005CJFAS..62.2632B }}</ref>  Adults can adapt to a [[euryhaline|broad range of salinity]],<ref name=nemesisserc>{{cite web|url=https://invasions.si.edu/nemesis/species_summary/97326|title=''Pacifastacus leniusculus''|website=Nemesis|publisher=Smithsonian Environmental Research Center|access-date=10 October 2024}}</ref><ref>{{cite book|last1=Kibenge |first1=Frederick S. B.|chapter=Chapter 1 - Introduction to the anatomy and physiology of the major aquatic animal species in aquaculture |date=2021-01-01 |doi=10.1016/B978-0-12-821339-1.00001-5|title=Aquaculture Pharmacology |pages=1–111 |editor-last=Kibenge |editor-first=Frederick S. B. |publisher=Academic Press |language=en |isbn=978-0-12-821339-1|last2=Strange |first2=Richard J. |editor2-last=Baldisserotto |editor2-first=Bernardo |editor3-last=Chong |editor3-first=Roger Sie-Maen}}</ref>{{rp|71}} substrate types and the presence of aquatic vegetation.<ref name=nemesisserc/>