Editing Sea cucumber (section)

=== Habitat ===
{{multiple image
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 | image1    = Pelagothuria natatrix (cropped).png
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 | caption1  = The mysterious ''[[Pelagothuria natatrix]]'' is the only truly [[pelagic]] echinoderm known to date.
 | image2    = Enypniastes sp.jpg
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 | caption2  = [[Elasipodida|Benthopelagic sea cucumber]]s, such as this ''[[Enypniastes]]'', are often confused with jellyfish, have webbed swimming structures enabling them to swim up off the surface of the seafloor and journey as much as {{convert|1000|m}} up the water column
 | image3    = Expl0790 - Flickr - NOAA Photo Library.jpg
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 | caption3  = Spanish dancer (''Benthodytes'' sp.), another swimming sea cucumber, hovering at {{convert|2789|m}} by the [[Davidson Seamount]]
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Sea cucumbers can be found in great numbers on the deep seafloor, where they often make up the majority of the animal biomass.<ref>{{cite web | url =http://jrscience.wcp.muohio.edu/fieldcourses05/PapersMarineEcologyArticles/SeaCucumbers.html| title = Sea Cucumbers | last = Miller | first = Nat | access-date =2007-10-03 }}</ref> At depths deeper than {{convert|5.5|mi|m|abbr=on|order=flip}}, sea cucumbers comprise 90% of the total mass of the macrofauna.<ref>{{cite web|url=http://www.answers.com/topic/sea-cucumberSci-Tech|title=Answers - The Most Trusted Place for Answering Life's Questions|work=Answers.com|access-date=12 June 2015}}</ref> Sea cucumbers form large herds that move across the bathygraphic features of the ocean, hunting food. The body of some deep water holothuroids, such as ''Enypniastes eximia'', ''Peniagone leander'' and ''Paelopatides confundens'',<ref>{{cite web|url=http://www7a.biglobe.ne.jp/~grafish/fa_abyssopelagic03.html|title=深海底帯底生魚|access-date=12 June 2015}}</ref> is made of a tough gelatinous tissue with unique properties that makes the animals able to control their own buoyancy, making it possible for them to either live on the ocean floor or to actively swim <ref>''Blue Planet'' Discovery Channel</ref> or float over it in order to move to new locations,<ref>{{cite web | url =http://www.oceanexplorer.noaa.gov/explorations/07mexico/logs/june18/june18.html| title = The Kingdom of the Echinoderm | date = 2007-06-18 | first =Bob | last = Carney | access-date = 2007-10-03 }}</ref> in a manner similar to how the group [[Torquaratoridae]] floats through water.

Holothuroids appear to be the echinoderms best adapted to extreme depths, and are still very diversified beyond {{convert|5,000|m}} deep: several species from the family [[Elpidiidae]] ("sea pigs") can be found deeper than {{convert|9,500|m}}, and the record seems to be some species of the genus ''[[Myriotrochus]]'' (in particular ''[[Myriotrochus bruuni]]''), identified down to {{convert|10,687|m}} deep.<ref name="MahDeepest">{{cite web|url=http://echinoblog.blogspot.fr/2014/04/what-are-deepest-known-echinoderms.html|title=What are the Deepest known echinoderms ? |last1=Mah|first1=Christopher L. |date=8 April 2014 |website=The Echinoblog }}</ref>
In more shallow waters, sea cucumbers can form dense populations. The strawberry sea cucumber (''Squamocnus brevidentis'') of [[New Zealand]] lives on rocky walls around the southern coast of the South Island where populations sometimes reach densities of {{convert|1,000|/m2|/sqft|abbr=on|disp=preunit|animals}}. For this reason, one such area in [[Fiordland]] is called the strawberry fields.<ref>{{cite journal | url =http://www.niwa.co.nz/news-and-publications/publications/all/abb/2003-03/cucumber| journal = Aquatic Biodiversity & Biosecurity Update|title= Sheddingnew light on the humble sea cucumber | access-date = 2007-10-03 | last =Alcock | first = Niki | year = 2003 | issue=3 }}</ref>