Editing Chinese mitten crab

{{Short description|Species of crab}}
{{Speciesbox
| image = EriocheirSinensis1.jpg
| genus = Eriocheir
| species = sinensis
| authority = [[Henri Milne-Edwards|H. Milne-Edwards]], 1853
}}
{{Infobox Chinese
|title="Chinese mitten crab"
|t=大閘蟹|s=大闸蟹|p=dà zhá xiè|lmz=du-zaq-ha<br />{{IPA|wuu|du zaʔ ha|}}
|c2=上海毛蟹|p2=shànghǎi máo xiè|lmz2=zaon-he mau-ha<br />{{IPA|wuu|z̥ɑ̃̀hé  mɔ ha|}}
}}
[[File:Chinese mitten crab total production thousand tonnes 1990-2022.svg|thumb|Capture (blue) and aquaculture (green) production of Chinese mitten crab (''Eriocheir sinensis'') in thousand tonnes from 1990 to 2022, as reported by the [[Food and Agriculture Organization|FAO]]<ref>{{Cite web |title=Fisheries and Aquaculture - Global Production |url=https://www.fao.org/fishery/en/collection/global_production?lang=en |access-date=2024-05-06 |website=Food and Agriculture Organization of the United Nations (FAO)}}</ref>]]

The '''Chinese mitten crab''' ('''''Eriocheir sinensis'''''; {{zh|t={{linktext|大閘蟹}}|s={{linktext|大闸蟹}}|p=dàzháxiè}}; [[Jyutping]]: daai6 zaap6 haai5; [[Shanghainese]]: ''du<sup>6</sup>-zaq<sup>8</sup>-ha<sup>5</sup>'', <small>{{abbr|lit.|Literally}}</small>&nbsp;"big [[sluice]] crab"), also known as the '''Shanghai hairy crab''' ({{lang|zh|{{linktext|上海毛蟹}}}}, <small>[[pinyin|p]]</small>&nbsp;''Shànghǎi máoxiè''),  is a medium-sized burrowing crab that is named for its furry claws, which resemble [[mittens]]. It is native to rivers, estuaries and other coastal habitats of [[East Asia]] from [[Korea]] in the north to [[Fujian]], China in the south. It has also been introduced to Europe and North America, where it is considered an [[invasive species]].<ref>{{cite web |url=http://www.wsg.washington.edu/mas/ecohealth/invasive_crabs/mitten_crab.html |title=Chinese mitten crab |date=March 29, 2000 |publisher=The Washington Sea Grant Program |access-date=February 24, 2012 |archive-url=https://web.archive.org/web/20100928002933/http://www.wsg.washington.edu/mas/ecohealth/invasive_crabs/mitten_crab.html |archive-date=September 28, 2010 |url-status=dead }}</ref><ref Name=issg.org>{{cite web |url=http://www.issg.org/database/species/ecology.asp?si=38&fr=1&sts= |title=Ecology of ''Eriocheir sinensis'' |author=Stephen Gollasch |date=March 3, 2006 |access-date=November 9, 2004 |archive-date=March 13, 2016 |archive-url=https://web.archive.org/web/20160313091158/http://issg.org/database/species/ecology.asp?fr=1&si=38&sts= |url-status=dead }}</ref> The species features on the [[list of invasive alien species of Union concern]].<ref>{{Cite web |title=List of Invasive Alien Species of Union concern - Environment - European Commission |url=https://ec.europa.eu/environment/nature/invasivealien/list/index_en.htm |access-date=2021-07-27 |website=ec.europa.eu}}</ref> This means that the import of the species and trade in the species is forbidden in the whole of the [[European Union]].<ref>{{Cite web |title=REGULATION (EU) No 1143/2014 of the European parliament and of the council of 22 October 2014 on the prevention and management of the introduction and spread of invasive alien species |url=https://eur-lex.europa.eu/legal-content/EN/TXT/PDF/?uri=CELEX:32014R1143&from=EN |url-status=live |archive-url=https://web.archive.org/web/20170303185733/http://eur-lex.europa.eu/legal-content/EN/TXT/PDF/?uri=CELEX:32014R1143&from=EN |archive-date=2017-03-03 }}</ref>

==Description and ecology==
This species' distinguishing features are the dense patches of dark [[seta]]e on its claws. The crab's body is the size of a human palm. The legs are about twice as long as the {{convert|3-10|cm|in|adj=mid|-wide|sp=us|frac=2}} carapace.

Chinese mitten crabs spend most of their life in [[fresh water]] and return to the sea to breed. The crabs have a lifespan around one to five years, depending on their location. Aquaculture farms in China report time to maturity between one and three years, while invasive crabs in colder European climates may take between four or five years. Once the age of maturity is reached, the crustaceans migrate downstream and attain sexual maturity in the tidal [[estuaries]]. After mating, the females continue seaward, overwintering in deeper waters. They return to [[brackish]] water in the spring to hatch their eggs. After development as [[crustacean larvae|larvae]], the juvenile crabs gradually move upstream into fresh water, thus completing the life cycle.<ref Name=issg.org/>

It moves from freshwater habitats to saltwater habitats once it has reached reproduction maturity. The types of estuaries suitable for the mitten crab include large brackish waters for the larva to develop in, and large shallow waters for the growth of the juvenile crabs.<ref>{{Cite web |url=http://www.issg.org/database/species/ecology.asp?si=38 |title=Eriocheir sinensis (Crustacean) |date=3 August 2009 |website=Global Invasive Species Database |last=Gollasch |first=Stephan |access-date=9 November 2004 |archive-date=4 September 2014 |archive-url=https://web.archive.org/web/20140904074300/http://www.issg.org/database/species/ecology.asp?si=38 |url-status=dead }}</ref> An increase in [[microplastics]] has had a significant impact on the population as it affects their metabolism, growth, and oxidative stress response in the liver.<ref>{{Cite journal |last1=Yang |first1=Xiaozhen |last2=Song |first2=Xiaozhe |last3=Zhang |first3=Cong |last4=Pang |first4=Yangyang |last5=Song |first5=Yameng |last6=Cheng |first6=Yongxu |last7=Nie |first7=Ling |last8=Zong |first8=Xin |date=2020 |title=Effects of dietary melatonin on hematological immunity, antioxidant defense and antibacterial ability in the Chinese mitten crab, ''Eriocheir sinensis'' |journal=Aquaculture |volume=529 |page=735578 |doi=10.1016/j.aquaculture.2020.735578 |bibcode=2020Aquac.52935578Y |s2cid=225032997 }}</ref><ref>{{Cite journal |last1=Yu |first1=Ping |last2=Liu |first2=Zhiquan |last3=Wu |first3=Donglei |last4=Chen |first4=Minghai |last5=Lv |first5=Weiwei |last6=Zhao |first6=Yunlong |date=2018 |title=Accumulation of polystyrene microplastics in juvenile ''Eriocheir sinensis'' and oxidative stress effects in the liver |journal=Aquatic Toxicology |volume=200 |pages=28–36 |doi=10.1016/j.aquatox.2018.04.015 |pmid=29709883 |bibcode=2018AqTox.200...28Y |s2cid=19096344 }}</ref>

The Chinese mitten crab originates from Hong Kong to the border of Korea.<ref name=":0">{{cite journal |author1=Herborg L. |author2=Rushton S. |author3=Clare A. |author4=Bentley M. |year=2003 |title=The spread of the Chinese mitten crab (''Eriocheir sinensis'' H. Milne Edwards) in Continental Europe: analysis of a historical data set |journal=Hydrobiologia |volume=503 |issue=1–3 |pages=21–28 |doi=10.1023/b:hydr.0000008483.63314.3c |bibcode=2003HyBio.503...21H |s2cid=12324387 }}</ref> It can be found inland but prefers coastal areas. In the [[Yangtze]], the largest river in its native range, Chinese mitten crabs have been recorded up to {{convert|1400|km|nmi|abbr=on}} upstream.<ref name=Eriocheir2007>{{cite report |author1=Veilleux, É |author2=de Lafontaine, Y. |year=2007 |title=Biological Synopsis of the Chinese Mitten Crab (''Eriocheir sinensis'') |series=Canadian Manuscript Report of Fisheries and Aquatic Sciences |volume=2812 }}</ref> It is known to settle in rice fields by the sea and rivers inland. The crab is found in [[subtropical]] and [[temperate]] regions.<ref name=":1">{{cite journal |author=Panning A |year=1938 |title=The Chinese mitten crab |url=http://www.vliz.be/imisdocs/publications/138001.pdf |journal=Smithsonian Rep |volume=1938 |pages=361–375 }}</ref>

[[Phylogenetically]] the crab belongs to the [[Varunidae]] family which is the newest group of [[brachyura]]n crustaceans. Spawning crabs average around {{convert|5.5|cm|in|frac=4|abbr=on}} in length. Since crabs spawn at the end of their life spans and perish at the end of the breeding cycle, the crabs can live up to 7 (in Germany also 8) years old.

The mitten crab diet is omnivorous. Their main prey consists of worms, mussels, snails, dead organic material, and other small crustaceans and fish.<ref name=":1" />

===Reproduction===
Mitten crabs are [[catadromous]] organisms, migrating from freshwater to saltwater for breeding. In late August, sexual instincts awaken and they begin migrating downstream to the sea, away from their feeding grounds. It is during this migration where the crabs reach puberty and develop their sex organs. The crabs begin to breed in the brackish waters in late fall. The males arrive first and stay in the brackish waters all winter; the females arrive after. The eggs are laid within 24 hours of mating, then attached to the abdomen of the female. After the eggs are attached, the female leaves immediately, heading to the mouth of the river. The larvae hatch from the eggs during the summer, after which they float and drift about the brackish waters. Because the journey to breed for crabs is so great, they only breed once during their lifetimes. The breeding age is normally toward the end of their lifespans. The crabs have sizable egg production count since these crabs only breed once. After the crabs successfully reproduce, they have very little energy and begin to waste away.<ref name=":1" />

Different life stages of the mitten crab:

# Eggs require pure salt water to mature.
# Larvae hatch from the eggs in brackish waters.
# The larvae gradually move from brackish water to fresh water.
# The final stage of the larvae is the [[megalopa]], which is {{convert|3|-|4|mm|in|frac=32|sp=us}} in length.
# The megalopa then develop into small mitten crabs in the freshwater.<ref name=":1" />

===Invasiveness===
This certain species of crab has been spreading rapidly from Asia (China and Korea) to North America and Europe, raising concerns that it competes with local species, and its burrowing nature damages embankments and clogs drainage systems.<ref>{{cite news |url=http://news.bbc.co.uk/2/hi/uk_news/england/4690988.stm |title=Exotic crabs in waterway invasion |work=[[BBC News]] |date=February 8, 2006}}</ref><ref>{{cite news |url=https://www.washingtonpost.com/wp-dyn/content/article/2006/08/07/AR2006080701309.html |title=Discovery of second invasive mitten crab raises worries |newspaper=[[The Washington Post]] |date=August 8, 2006 |author1=Elizabeth Williamson |author2=David A. Fahrenthold }}</ref> The crabs can make significant inland migrations. It was reported in 1995 that residents of [[Greenwich]] saw Chinese mitten crabs coming out of the [[River Thames]], and in 2014 one was found in the [[River Clyde|Clyde]], in Scotland.<ref>[https://www.bbc.com/news/uk-scotland-29365132 Invasion warning on Scotland's rivers], BBC News, 25 September 2014</ref> The crabs have also been known to take up residence in [[swimming pool]]s. In some places, the crabs have been found hundreds of miles from the sea. There is concern in areas with a substantial native crab fishery, such as the [[Chesapeake Bay]] in [[Maryland]] and the [[Hudson River]] in [[New York (state)|New York]] (both locations where the crabs were first spotted in 2005), as the impact of the invasion by this species on the native population is unknown.<ref>{{cite news |url=http://www.recordonline.com/apps/pbcs.dll/article?AID=/20070616/NEWS/706160336 |title=Fishermen Fear a Mitten Crab Invasion |author=Greg Bruno |date=June 16, 2006 |publisher=[[Times Herald-Record]] |access-date=June 27, 2007 |archive-date=February 13, 2020 |archive-url=https://web.archive.org/web/20200213182206/https://www.recordonline.com/apps/pbcs.dll/article?AID=/20070616/NEWS/706160336 |url-status=dead }}</ref>

It is generally illegal to import, transport, or possess live Chinese mitten crabs in the United States,<ref name="50CFR16.13">{{cite web |url=http://edocket.access.gpo.gov/cfr_2008/octqtr/50cfr16.13.htm |title=Title 50 – Wildlife and Fisheries. Part 16: Injurious Wildlife |work=[[Code of Federal Regulations]] |date=October 1, 2008}}</ref> as accidental release or escape risks spreading these crabs to uninfested waters. In addition, some states may have their own restrictions on possession of mitten crabs.<ref name="14CCR671">[[California Code of Regulations]], Title 14, Section 671</ref> California allows fishing for mitten crabs with some restrictions.<ref name="Bay Delta Region">{{cite web |url=http://www.delta.dfg.ca.gov/mittencrab/life_hist.asp |title=Chinese Mitten Crab: Life and History |publisher=[[California Department of Fish and Game]] |date=August 5, 1998 |access-date=December 25, 2008 |archive-url=https://web.archive.org/web/20090117002542/http://www.delta.dfg.ca.gov/mittencrab/life_hist.asp |archive-date=January 17, 2009 |url-status=dead }}</ref>

The Chinese mitten crab has been introduced into the [[Great Lakes]] several times but has not yet been able to establish a permanent population.<ref>{{cite web |author=P. D. N. Hebert |title=Canada's Freshwater Invertebrates: Decapoda |work=Canada's Aquatic Environments |publisher=[[University of Guelph]] |url=http://www.aquatic.uoguelph.ca/inverts/diver/arthropods/crust/decap.htm }}{{Dead link|date=July 2020 |bot=InternetArchiveBot |fix-attempted=yes }}</ref>

The [[Smithsonian]] is tracking the spread of the Chinese mitten crab and seeking help to determine the current distribution status of the mitten crab along all coasts of North America, especially [[Chesapeake Bay]], [[Delaware Bay]], [[Hudson River]], and [[San Francisco Bay]]. People are encouraged to report any mitten crab sightings, along with details (date, specific location, size) and a close-up photograph or specimen if possible. The first confirmed record along the [[East coast of the United States]] was in the Chesapeake Bay near [[Baltimore]], Maryland, in 2005.<ref name="SERC">{{cite web |url=http://mittencrab.nisbase.org/|title=Chinese Mitten Crabs have come to the East Coast of the United States: We are seeking reports of mitten crab sightings and collections |publisher=[[Smithsonian Environmental Research Center]] |date=May 8, 2011}}</ref><ref>
{{cite web
|author=<!-- not stated --> 
|date        = 
|title=Research Project: Invading Mitten Crabs - Tracking Their Current Status and Spread in North America
|url=https://serc.si.edu/research/projects/invading-mitten-crabs
|publisher=[[Smithsonian Environmental Research Center]]
|access-date=2005-04-30
}}
</ref>

Chinese mitten crabs have also invaded German waters, where they destroy fishing nets, hurt native fish species and damage local dams, causing damage of up to 80 million Euros. These crabs migrated from China to Europe as early as 1900 and were first documented by official German reports in 1912 from Aller River. After an investigation by German scientists in 1933, it was thought that the crabs migrated to Europe through ballast water in commercial ships. The crabs are the only freshwater crab species in Germany, and their tendency to dig holes has caused damage to industrial infrastructure and dams.<ref>3 September 2012, [http://news.sina.com.cn/c/2012-09-03/033825087121.shtml 中国大闸蟹入侵德国水域致德损失达8千万欧元] (Chinese mitten crabs invade German waters, cause damage of 80 million Euros), [[Sina.com|Sina News]]</ref>

The first time the crab was brought to Europe was most likely by commercial vessels. Ships must fill their ballast water tanks and during one of these filling events, it could have been the spawning time for the mitten crab. Since the larvae are free floating and {{convert|1.7|-|5|mm|frac=32|sp=us}} in size, it would have been easy for them to be swept into the ballast water tank. Once the ship reached Europe and emptied its tank, the crab larvae were released. Over time, this repetition would allow for a prominent mitten crab population in Europe.<ref name=":1" /> The crab has spread and can be found in Continental Europe, Southern France, United States of America (the San Francisco Bay), and the United Kingdom.  A 15-year period in Germany when the crabs were gradually entering Europe is known as the "establishment phase".<ref name=":0" />

==Culinary==
{{missing information|section|the 蟹黄 of male crabs — not quite the roe, but also reproductive and culinarily similar|date=January 2023}}
Crabs are an autumnal delicacy in [[Shanghai cuisine]] and eastern China. It is prized for the female crab roe, which ripen in the ninth lunar month and the males in the tenth.<ref>{{cite news |last=Dunlop |first=Fuchsia |title=The Chinese delicacy of hairy crabs |url=https://www.bbc.co.uk/news/magazine-20701058 |access-date=15 December 2012 |newspaper=BBC News Magazine |date=15 December 2012}}</ref> The crab meat is believed by [[traditional Chinese medicine]] practitioners to have a "cooling" ([[Yin and yang|yin]]) effect on the body.

Crabs from Yangcheng Lake are especially prized, since they are perceived to have sweeter meat.<ref name="NPR.org">{{Cite news |title=Something's Fishy About Chinese Hairy Crabs |language=en |work=NPR.org |url=https://www.npr.org/2011/10/10/141134793/somethings-fishy-about-chinese-hairy-crabs |access-date=2022-06-25}}</ref> Most of the Yangcheng crabs are exported to [[Shanghai]] and [[Hong Kong]], and high-profit foreign markets. Responding to the spread of the crab to the West, businessmen have started seeing it as a new source of crab for the Chinese market. One proposed scheme involves importing unwanted crabs from Europe, where they are seen as a pest, to replenish local pure-bred stock.

Mitten crabs have exhibited a remarkable ability to survive in highly modified aquatic habitats, including polluted waters.<ref name=issg.org/> Like some fish, they can also easily tolerate and uptake heavy metals, such as [[cadmium]] and [[Mercury (element)|mercury]]. Therefore, the farming and post-harvesting of the species needs proper management if it is used as a food.<ref name=mbcmc>{{cite journal |author1=Clifford A. Hui |author2=Deborah Rudnick |author3=Erin Williams |title=Mercury burdens in Chinese mitten crabs (''Eriocheir sinensis'') in three tributaries of southern San Francisco Bay, California, USA |journal=[[Environmental Pollution (journal)|Environmental Pollution]] |volume=133 |issue=3 |pages=481–487 |year=2005 |doi=10.1016/j.envpol.2004.06.019 |pmid=15519723|bibcode=2005EPoll.133..481H }}</ref><ref name=uctip>{{cite journal |author1=F. Silvestre |author2=G. Trausch |author3=A. Péqueux |author4=P. Devos |title=Uptake of cadmium through isolated perfused gills of the Chinese mitten crab, ''Eriocheir sinensis'' |journal=Comparative Biochemistry and Physiology A |volume=137 |issue=1 |pages=189–196 |year=2004 |doi=10.1016/S1095-6433(03)00290-3 |pmid=14720604}}</ref> Concerns have been raised that the population and origin of the crab may be affected because of overfishing of the species in the [[Yangtze]].

In 2010, a Chinese businessman introduced vending machines to sell this species of crab in the subways.<ref>[https://www.youtube.com/watch?v=5Mwv90m3N2Y Associated Press Video]</ref> The crabs are stored at {{convert|5|C|F}}, which induces a sleep-like state.<ref>Gizmodo [https://gizmodo.com/5670648/this-vending-machine-sells-live-crabs "Vending Machine Sells Live Crabs"] {{Webarchive|url=https://web.archive.org/web/20170617072340/http://gizmodo.com/5670648/this-vending-machine-sells-live-crabs |date=2017-06-17 }}</ref>

<gallery widths="200px" heights="200px">
File:Gekochte Wollhandkrabben.jpg|Hairy crab is an important part of [[Shanghai cuisine]]
File:Roe inside steamed female hairy crab.jpg|Closeup of the roe inside a steamed female crab
</gallery>

=== Counterfeit Yangcheng Lake crabs ===
Counterfeit crabs are a problem in the hairy crab industry. Due to the high demand for hairy crabs specifically from Yangcheng Lake, many vendors sell hairy crabs from other lakes and claim they are authentic Yangcheng Lake hairy crabs. Although only 3,000 tons of Yangcheng Lake hairy crabs were harvested in 2012, more than 100,000 tons of supposed "Yangcheng" crabs were sold.<ref name="NPR.org"/><ref name=":2">{{Cite web |title=Now, fake hairy crabs |url=http://www.chinadaily.com.cn/en/doc/2003-10/21/content_274117.htm |access-date=2022-06-25 |website=www.chinadaily.com.cn}}</ref>

"Bathing crabs" are hairy crabs sourced from elsewhere which are temporarily placed in Yangcheng Lake and then fraudulently sold as genuine Yangcheng Lake hairy crabs.<ref name=":Liu">{{Cite book |last=Liu |first=Lizhi |title=From Click to Boom: The Political Economy of E-Commerce in China |publisher=[[Princeton University Press]] |year=2024 |isbn=9780691254104 |pages=70}}</ref>

Identifying counterfeit crabs is a hard task, as the Yangcheng Lake hairy crabs look exactly like other hairy crabs. Technology has been implemented to identify fake hairy crabs, such as laser tags, prints, and barcodes, but these are easily forged.<ref name=":2" /> Blockchain-based tracing has also been implemented, where caught crabs are entered into a blockchain.<ref>{{Cite web |title=Chinese Search Giant Baidu Launches A Blockchain Applet To Tackle 'Counterfeit' Yangcheng Lake Hairy Crabs {{!}} NEWS.8BTC.COM |url=https://news.8btc.com/chinese-search-giant-baidu-launches-a-blockchain-applet-to-tackle-counterfeit-yangcheng-lake-hairy-crabs |access-date=2022-06-25 |language=en-US |archive-date=2021-10-20 |archive-url=https://web.archive.org/web/20211020013110/https://news.8btc.com/chinese-search-giant-baidu-launches-a-blockchain-applet-to-tackle-counterfeit-yangcheng-lake-hairy-crabs |url-status=dead }}</ref> Efforts to combat bathing crabs are ongoing.<ref>{{cite web |last=Yan |first=Alice |date=6 October 2012 |title=Trade in fake Yangcheng Lake hairy crabs rampant |url=https://www.scmp.com/comment/article/1054958/trade-fake-yangcheng-lake-hairy-crabs-rampant |access-date=25 June 2022 |website=[[South China Morning Post]]}}</ref>

==Management efforts==
Management efforts have been shown to be very difficult. This is due to its abundance, high reproductive rate, and high physiological tolerance. All the following efforts were attempted but showed little improvement: "catch as many as you can", migration barriers, trapping, raising awareness,  electrical screens, and pulses.<ref name="issg.org" />

There has been a discussion of capturing the breeding crabs at the river mouths. There have been difficulties in carrying out this plan though. Other strategies such as capturing them when they pile up at dams have proven somewhat effective. The problem arises when the crabs climb the walls of the dams and over into the rivers behind the dams.<ref name=":1" />

==References==
{{Reflist|32em}}

==External links==
{{Commons category|Eriocheir sinensis|''Eriocheir sinensis''}}
* [https://www.invasivespeciesinfo.gov/aquatic/invertebrates/chinese-mitten-crab Species Profile – Chinese mitten crab (''Eriocheir sinensis'')], National Invasive Species Information Center, [[United States National Agricultural Library]]
* [http://mittencrab.nisbase.org/ Mitten Crab Watch] - Smithsonian Environmental Research Center

{{Shanghai cuisine}}
{{Edible crustaceans}}
{{Portal bar|Food|China}}
{{Taxonbar|from=Q823941}}
{{Authority control}}

{{DEFAULTSORT:Chinese Mitten Crab}}
[[Category:Grapsoidea]]
[[Category:Freshwater crustaceans of Asia]]
[[Category:Edible crustaceans]]
[[Category:Shanghai cuisine]]
[[Category:Crustaceans described in 1853]]
[[Category:Taxa named by Henri Milne-Edwards]]