Editing Crayfish (section)

== Threats to crayfish ==

Crayfish are susceptible to infections such as [[crayfish plague]] and to environmental stressors including acidification. In Europe, they are particularly threatened by crayfish plague, which is caused by the North American [[water mold]] ''Aphanomyces astaci.'' This water mold was transmitted to Europe when North American species of crayfish were introduced.<ref name="lee-james"/> Species of the genus ''[[Astacus]]'' are particularly susceptible to infection, allowing the plague-coevolved [[signal crayfish]] (native to western North America) to invade parts of [[Europe]].<ref>{{Cite web |title = Nonindigenous Aquatic Species - Pacifastacus leniusculus |url = https://nas.er.usgs.gov/queries/FactSheet.aspx?speciesID=200 |access-date = 6 July 2020 }}</ref>

[[Acid rain]] can cause problems for crayfish across the world. In whole-ecosystem experiments simulating acid rain at the [[Experimental Lakes Area]] in [[Ontario|Ontario, Canada]], crayfish populations crashed – probably because their [[exoskeleton]]s are weaker in [[Freshwater acidification|acidified]] environments.<ref>{{Cite web |date = 16 May 2018 |title = A Canadian Scientist Explains How Acid Rain is Still Making its Mark |url = https://www.iisd.org/ela/blog/research-highlights/acid-rain-totally-last-century-right-not-exactly-canadian-scientist-explains-acid-rain-still-making-mark/ |access-date = 6 July 2020 |website = IISD Experimental Lakes Area }}</ref>