View source for Oyster

{{Short description|Variety of families of Mollusca}}
{{Other uses}}
{{cs1 config|name-list-style=vanc}}
{{Use dmy dates|date=December 2023}}
{{missing information|oyster reproduction, including its "set"|date=June 2025}}
{{Paraphyletic group
| fossil_range = {{Fossil Range|252|0}}
| name = Oyster
| image = Crassostrea gigas p1040848.jpg
| image_alt = Pacific oyster from the Marennes-Oléron basin in France
| image_caption = [[Pacific oyster]] from the [[Marennes, Charente-Maritime|Marennes]]-[[Oléron]] basin in France
| auto = yes
| parent = Pteriomorphia
| includes = *[[Anomiidae]] – saddle oysters
* [[Dimyidae]] – dimyarian oysters
* [[Gryphaeidae]] – foam oysters
* [[Malleidae]] – hammer oysters
* [[Ostreidae]] – true oysters
* [[Placunidae]] – windowpane oysters
* [[Pteriidae]] – winged, tree and pearl oysters
* [[Spondylidae]] – spiny oysters
| excludes = All other members of [[Pteriomorphia]]
}}
[[File:Oyster dubai.jpg|thumb|Mixed seafood in Dubai; oysters are at the edge of the tray]]
'''Oyster''' is the [[common name]] for a number of different families of [[Seawater|salt-water]] [[bivalve]] [[mollusc]]s that live in [[Marine (ocean)|marine]] or [[Brackish water|brackish]] habitats. In some species, the valves are highly [[Calcification|calcified]], and many are somewhat irregular in shape. Many, but not all oysters, are in the superfamily [[Ostreoidea]].

Some species of oyster are commonly consumed and are regarded as a [[delicacy]] in some localities. Some types of [[pearl oyster]]s are harvested for the [[pearl]] produced within the [[Mantle (mollusc)|mantle]]. Others, such as the translucent [[windowpane oyster]]s, are harvested for their shells.

==Etymology==
The word ''oyster'' comes from [[Old French]] {{lang|fro|oistre}}, and first appeared in English during the 14th century.<ref>{{usurped|1=[https://web.archive.org/web/20130510030403/http://www.celtnet.org.uk/recipes/forme-cury-5.php Oysters in Cynee]}},
Recipe for Oysters in Bread Sauce (Oysters in Cynee) from the 1390 English text, ''The Forme of Cury'', from Celtnet Recipes</ref>  The French derived from the [[Latin]] {{lang|la|ostrea}}, the feminine form of {{lang|la|ostreum}},<ref>[https://www.perseus.tufts.edu/hopper/text?doc=Perseus%3Atext%3A1999.04.0059%3Aentry%3Dostrea ostrea, ostreum],
Charlton T. Lewis, Charles Short, ''A Latin Dictionary'', on Perseus</ref> which is the [[Latinisation (literature)|latinisation]] of the [[Ancient Greek]] {{lang|grc|ὄστρεον}} ({{Transliteration|grc|ostreon}}) 'oyster'.<ref>{{Cite book|author1=Henry George Liddell | author2= Robert Scott | title= A Greek-English Lexicon | chapter = ὄστρεον| chapter-url=https://www.perseus.tufts.edu/hopper/text?doc=Perseus:text:1999.04.0057:entry=o%29%2Fstreon |via=perseus.tufts.edu
| editor1= Henry Stuart Jones | editor2= Roderick McKenzie
| place= Oxford| publisher= Clarendon Press| date= 1940
}}
</ref> Compare {{lang|grc|ὀστέον}} ({{Transliteration|grc|osteon}}) 'bone'.<ref>{{Cite book|author1=Henry George Liddell | author2= Robert Scott | title= A Greek-English Lexicon | chapter =ὀστέον| chapter-url=https://www.perseus.tufts.edu/hopper/text?doc=Perseus:text:1999.04.0057:entry=o)ste/on|via=perseus.tufts.edu
| editor1= Henry Stuart Jones | editor2 =Roderick McKenzie
| place= Oxford| publisher= Clarendon Press| date= 1940
}}</ref>

==Types==

===True oysters===

[[True oyster]]s are members of the family [[Ostreidae]]. This family includes the edible oysters, which mainly belong to the genera ''[[Ostrea]]'', ''[[Crassostrea]]'', ''[[Magallana]]'', and ''[[Saccostrea]]''. Examples include the [[European flat oyster]], [[eastern oyster]], [[Olympia oyster]], [[Pacific oyster]], and the [[Sydney rock oyster]]. Ostreidae evolved in the [[Early Triassic]] [[epoch (geology)|epoch]]: The [[genus]] ''[[Liostrea]]'' grew on the shells of living [[ammonoids]].<ref>{{cite journal | url=https://academic.oup.com/mollus/article/83/3/253/3862014 | doi=10.1093/mollus/eyx018 | title=Geologically oldest oysters were epizoans on Early Triassic ammonoids | year=2017 | last1=Hautmann | first1=Michael | last2=Ware | first2=David | last3=Bucher | first3=Hugo | journal=Journal of Molluscan Studies | volume=83 | issue=3 | pages=253–260 | doi-access=free }}</ref>

===Pearl oysters===

[[File:Pearl Oysters.jpg|thumb|right|Removing a [[pearl]] from a pearl oyster|alt=Photo of opened oyster in bowl with person using a knife to remove the pearl]]
{{Main|Pearl oyster}}
Almost all shell-bearing mollusks can secrete pearls, yet most are not very valuable. Pearls can form in both saltwater and freshwater environments.

[[Pearl oyster]]s are not closely related to true oysters, being members of a distinct family, the feathered oysters ([[Pteriidae]]). Both [[cultured pearl]]s and [[natural pearl]]s can be extracted from pearl oysters, though other molluscs, such as the freshwater [[mussel]]s, also yield pearls of commercial value.

The largest pearl-bearing oyster is the marine ''Pinctada maxima'', which is roughly the size of a dinner plate. Not all individual oysters produce pearls.

In nature, pearl oysters produce pearls by covering a minute invasive object with [[nacre]]. Over the years, the irritating object is covered with enough layers of nacre to become a pearl. The many different types, colours and shapes of pearls depend on the natural [[pigment]] of the nacre, and the shape of the original irritant.

Pearl farmers can culture a pearl by placing a nucleus, usually a piece of polished mussel shell, inside the oyster. In three to seven years, the oyster can produce a perfect pearl. Since the beginning of the 20th century, when several researchers discovered how to produce artificial pearls, the cultured pearl market has far outgrown the natural pearl market.<ref>{{cite journal |title       = A History of the Cultured Pearl Industry
 |year = 2013
 |publisher   = [[BioOne]]
 |doi = 10.2108/zsj.30.783
 |last1 = Nagai
 |first1 = Kiyohito
 |journal = Zoological Science
 |volume = 30
 |issue = 10
 |pages = 783–793
 |pmid = 24125642
 |s2cid = 1429376
 |doi-access = free
 }}</ref>

===Other types===

A number of bivalve molluscs (other than true oysters and pearl oysters) also have common names that include the word "oyster", usually because they either taste like or look somewhat like true oysters, or because they yield noticeable pearls. Examples include:
* [[Thorny oyster]]s in the genus ''Spondylus''
* Pilgrim oyster, another term for a [[scallop]], in reference to the scallop shell of St. James
* [[Saddle oyster]]s, members of the [[Anomiidae]] family also known as jingle shells
* [[Dimyidae|Dimydarian oysters]], members of the family Dimyidae
* [[Windowpane oyster]]s

<gallery widths="175px" heights="175px">
File:Crassostrea_gigas_p1040847.jpg|[[Pacific oyster]]
File:Ostrea edulis Marennes p1050142.jpg|[[Pacific oyster]], opened
</gallery>

In the [[Philippines]], a local thorny oyster species known as [[Tikod amo]] is a favorite seafood source in the southern part of the country.<ref>{{Cite news|url=http://www.worldngayon.com/2011/12/native-oyster-species-in-surigao-del-sur-draws-attention-for-rd/|title=Native oyster species in Surigao del Sur draws attention for R&D {{!}} eVolved|date=2 December 2011|work=eVolved|access-date=12 December 2017|language=en-US}}</ref> Because of its good flavor, it commands high prices.

== Anatomy ==
Oysters breathe primarily via [[gill]]s. In addition to their gills, oysters can exchange gases across their [[Mantle (mollusc)|mantles]], which are lined with many small, thin-walled [[blood vessels]]. A small, three-chambered [[heart]], lying under the [[Adductor muscle (Bivalvia)|adductor muscle]], pumps colorless [[blood]] to all parts of the body. At the same time, two [[kidneys]], located on the underside of the muscle, remove waste products from the blood. Their nervous system includes two pairs of nerve cords and three pairs of [[ganglia]]. There is no evidence that oysters have a brain.

While some oysters have two sexes ([[European oyster]] and [[Olympia oyster]]), their reproductive organs contain both eggs and sperm. Because of this, it is technically possible for an oyster to fertilize its own eggs. The [[gonads]] surround the digestive organs, and are made up of sex cells, branching tubules, and connective tissue.

Once her millions of eggs are fertilized, the female discharges them into the water. The [[larvae]] develop in about six hours and exist suspended in the water column as [[veliger|veliger larvae]] for two to three weeks before settling on a bed and reaching sexual maturity within a year.

== Feeding ==
Oysters are [[filter feeder]]s, drawing water in over their [[gill]]s through the beating of [[cilia]]. Suspended [[plankton]] and non-food particles are trapped in the [[mucus]] of a gill, and from there are transported to the mouth, where they are eaten, digested, and expelled as [[feces]] or [[pseudofeces]] that fall to the bottom and remain out of the water column. Oysters feed most actively at temperatures ranging from the high 60s to the high 70s ({{cvt|68|-|78|F|C|disp=out}}).<ref>{{Cite web |last=Wheeler |first=Timothy B. |date=20 May 2020 |title=Pumped-up performance: Oysters' filtering feat overstated |url=https://www.bayjournal.com/news/fisheries/pumped-up-performance-oysters-filtering-feat-overstated/article_bbe67d38-8f09-11ea-a5ab-5fd7465dee21.html |access-date=14 April 2022 |website=Bay Journal |language=en}}</ref> Under ideal laboratory conditions, an oyster can filter up to {{Convert|50|USgal|l||order=flip|abbr=on}} of water per day. Under average conditions, mature oysters filter {{Convert|3|-|12|U.S.gal|l|order=flip|abbr=on}}. [[Chesapeake Bay]]'s once-flourishing oyster population historically filtered excess nutrients from the estuary's entire water volume every three to four days. As of 2008 it was estimated that a complete cycle would take nearly a year.<ref>{{cite web |title=Oyster Reefs: Ecological importance |url=http://www.habitat.noaa.gov/pdf/value_of_oysters.pdf |url-status=dead |archive-url=https://web.archive.org/web/20140908044948/http://www.habitat.noaa.gov/pdf/value_of_oysters.pdf |archive-date=8 September 2014 |access-date=16 January 2008 |publisher=US National Oceanic and Atmospheric Administration}}</ref>

== Habitat and behaviour ==
[[File:Oyster reef Hunting Island SC.jpg|thumb|right|Oyster reef at about mid-tide off fishing pier at [[Hunting Island State Park]], South Carolina]]
A group of oysters is commonly called a bed or [[oyster reef]].
[[File:Oyster Dalian.JPG|thumb|Rocks in [[intertidal zone]] covered by oysters, at Bangchuidao Scenic Area, [[Dalian]], [[Liaoning Province]], China]]

Oysters are [[filter feeders]], taking in large amounts of water to feed and breathe (exchange {{O2}} and {{CO2}} with water) but they are not permanently open. They regularly shut their valves to enter a resting state, even when they are permanently submersed. Their behaviour follows very strict circatidal and circadian rhythms according to the relative moon and sun positions. During neap tides (the time periods of mildly shifting tides), they exhibit much longer closing periods than during the spring tide (the time period of more drasticly shifting tides).<ref>{{cite journal | pmid=21539422 | year=2011 | last1=Tran | first1=D. | last2=Nadau | first2=A. | last3=Durrieu | first3=G. | last4=Ciret | first4=P. | last5=Parisot | first5=J. P. | last6=Massabuau | first6=J. C. | title=Field chronobiology of a molluscan bivalve: How the moon and sun cycles interact to drive oyster activity rhythms | journal=Chronobiology International | volume=28 | issue=4 | pages=307–317 | doi=10.3109/07420528.2011.565897 | s2cid=25356955 }}</ref>

As a [[keystone species]], oysters provide [[Habitat (ecology)|habitat]] for many marine species.
''Crassostrea'' and ''Saccostrea'' live mainly in the [[intertidal zone]], while ''Ostrea'' is [[subtidal]]. The hard surfaces of oyster shells and the nooks between the shells provide places where a host of small animals can live. Hundreds of animals, such as [[sea anemones]], [[barnacles]], and [[Ischadium recurvum|hooked mussels]], inhabit [[oyster reef]]s. Many of these animals are prey to larger animals, including fish, such as [[striped bass]], [[black drum]] and [[croakers]].

An oyster reef can increase the surface area of a flat bottom 10-fold.{{cn|date=June 2025}} An oyster's mature shape often depends on the type of bottom to which it is originally attached, but it always orients itself with its outer, flared shell tilted upward. One valve is cupped and the other is flat.

===Reproduction===
Oysters usually reach maturity in one year. They are [[protandric]]; during their first year, they spawn as males by releasing [[sperm]] into the water. As they grow over the next two or three years and develop greater energy reserves, they spawn as females by releasing [[egg (biology)|eggs]]. [[Bay oyster]]s usually spawn from the end of June until mid-August. An increase in water temperature prompts a few oysters to spawn. This triggers spawning in the rest, clouding the water with millions of eggs and sperm. A single female oyster can produce up to 100 million eggs annually. The eggs become fertilized in the water and develop into larvae, which eventually find suitable sites, such as another oyster's shell, on which to settle. Attached oyster larvae are called spat. Spat are oysters less than {{convert|25|mm|in|abbr=on|0}} long. Many species of bivalves, oysters included, seem to be stimulated to settle near adult [[conspecific]]s.

[[File:Electric oyster MolluSCAN eye project.jpg|thumb|left|Pacific oyster ''[[Crassostrea gigas]]'' equipped with activity electrodes to follow their daily behaviour]]

Some tropical oysters, such as the [[mangrove oyster]] in the family [[Ostreidae]], grow best on [[mangrove]] roots. Low tide can expose them, making them easy to collect.

The largest oyster-producing body of water in the [[United States]] is the [[Chesapeake Bay]], although these beds have decreased in number due to overfishing and pollution. Other large [[oyster farming]] areas in the US include the bays and estuaries along the coast of the [[Gulf of Mexico]] from [[Apalachicola, Florida]], in the east to [[Galveston, Texas]], in the west. Large beds of edible oysters are also found in Japan and Australia. In 2005, China accounted for 80% of the global oyster harvest.<ref>{{cite web
|
url=http://www.fao.org/figis/servlet/SQServlet?file=/usr/local/tomcat/FI/5.5.23/figis/webapps/figis/temp/hqp_30190.xml&outtype=html
|
title=China harvests almost 4 m tonnes of oyster in 2005
|
access-date=12 July 2008
|
archive-date=26 January 2012
|
archive-url=https://web.archive.org/web/20120126052340/http://www.fao.org/figis/servlet/SQServlet?file=/usr/local/tomcat/FI/5.5.23/figis/webapps/figis/temp/hqp_30190.xml&outtype=html
|
url-status=dead
}}</ref> In Europe, France remained the industry leader.

===Predation===
Common oyster predators include [[crab]]s, [[seabird]]s, [[starfish]], and [[human]]s. Some oysters contain crabs, known as [[oyster crab]]s.<ref>{{cite journal |last1=Christensen |first1=Aage Møller |last2=McDermott |first2=John J. |title=Life-History and Biology of the Oyster Crab, Pinnotheres ostreum Say |journal=Biological Bulletin |date=April 1958 |volume=14 |issue=2 |pages=146–179|doi=10.2307/1538845 |jstor=1538845 |s2cid=88045743 |url=https://www.biodiversitylibrary.org/part/16401 }}</ref>

==Nutrient cycling==
[[Bivalves]], including oysters, are effective filter feeders and can have large effects on the water columns in which they occur.<ref>{{cite journal | pmid=21558200 | year=2010 | last1=Padilla | first1=D. K. | title=Context-dependent impacts of a non-native ecosystem engineer, the Pacific oyster Crassostrea gigas | journal=Integrative and Comparative Biology | volume=50 | issue=2 | pages=213–225 | doi=10.1093/icb/icq080 | doi-access=free }}</ref> As filter feeders, oysters remove plankton and organic particles from the water column.<ref name="jud and layman">{{cite web |first1=Zachary |last1=Jud |first2=Craig |last2=Layman |year=2011 |title=Loxahatchee River oyster reef restoration monitoring report: Using baselines derived from long-term monitoring of benthic community structure on natural oyster reefs to assess the outcome of large-scale oyster reef restoration |work=Martin County, Florida |url=https://loxahatchee-qnewmedia.netdna-ssl.com/pdf/FIU_NOAAMonitRpt_2011.pdf |access-date=14 July 2022 |archive-date=8 August 2022 |archive-url=https://web.archive.org/web/20220808180240/https://loxahatchee-qnewmedia.netdna-ssl.com/pdf/FIU_NOAAMonitRpt_2011.pdf |url-status=dead }}</ref> Multiple studies have shown individual oysters are capable of filtering up to {{convert|190|L}} of water per day, and thus oyster reefs can significantly improve water quality and clarity.<ref>{{cite journal |url=https://academic.oup.com/icb/article/37/6/612/115863 |doi=10.1093/icb/37.6.612 |title=Bacteria, Dissolved Organics and Oxygen Consumption in Salinity Stratified Chesapeake Bay, an Anoxia Paradigm | year=1997 | last1=Jonas | first1=Robert B. | journal=American Zoologist | volume=37 | issue=6 | pages=612–620 | doi-access=free }}</ref><ref>{{cite journal |last1=Officer |first1=C.B. |last2=Smayda |first2=T.J. |last3=Mann |first3=R. |year=1982 |title=Benthic Filter Feeding – a Natural Eutrophication Control |journal=[[Marine Ecology Progress Series]] |volume=9 |pages=203–210 |doi=10.3354/meps009203 |bibcode=1982MEPS....9..203O |url=https://www.int-res.com/articles/meps/9/m009p203.pdf }}</ref><ref>{{cite journal | url=https://www.jstor.org/stable/1352778 | jstor=1352778 | title=The Trophic Consequences of Oyster Stock Rehabilitation in Chesapeake Bay | last1=Ulanowicz | first1=Robert E. | last2=Tuttle | first2=Jon H. | journal=Estuaries | year=1992 | volume=15 | issue=3 | pages=298–306 | doi=10.2307/1352778 | s2cid=84975440 }}</ref><ref>Newell, R. 2004. Ecosystem Influences of Natural and Cultivated Populations of Suspension-Feeding Bivalve Molluscs: A Review. J. Shellfish Research, 23(1):51-61.</ref> Oysters consume nitrogen-containing  compounds ([[nitrate]]s and [[ammonia]]), [[phosphate]]s, plankton, detritus, bacteria, and dissolved organic matter, removing them from the water.<!-- repetitiveOysters feed on plankton, incidentally consuming nitrogen compounds, as well. --><ref>{{cite journal |doi=10.1017/S0025315400052589 |url=https://www.cambridge.org/core/journals/journal-of-the-marine-biological-association-of-the-united-kingdom/article/abs/feeding-by-oyster-larvae-the-functional-response-energy-budget-and-a-comparison-with-mussel-larvae/6B4CC491635F66929B33F1F8D164A9D6 |title=Feeding by Oyster Larvae: The Functional Response, Energy Budget and a Comparison with Mussel Larvae |year=1985 |last1=Crisp |first1=D. J. |last2=Yule |first2=A. B. |last3=White |first3=K. N. |journal=Journal of the Marine Biological Association of the United Kingdom |volume=65 |issue=3 |pages=759–783 |bibcode=1985JMBUK..65..759C |s2cid=83713773 |url-access=subscription }}</ref> What is not used for animal growth is then expelled as solid waste pellets, which eventually decompose into the atmosphere as nitrogen.<ref name=econ>{{cite news
|url=http://www.economist.com/world/unitedstates/displaystory.cfm?story_id=12795573
|title=A dozen ocean-cleaners and a pint of Guinness, please
|access-date=26 December 2008
|newspaper=The Economist
|date=18 December 2008}}</ref> In [[Maryland]], the [[Chesapeake Bay Program]] had implemented a plan to use oysters to reduce the amount of nitrogen compounds entering the [[Chesapeake Bay]] by {{convert|8600|MT|ST|abbr=on}} per year by 2010.<ref>{{cite web
 |url=http://www.dnr.state.md.us/dnrnews/pressrelease2005/081505.html
 |title=Oyster Restoration Projected to Provide Significant Boost to Bay Grasses While Removing Nitrogen Pollution from the Bay
 |access-date=26 December 2008
 |website=Maryland Department of Natural Resources
 |url-status=dead
 |archive-url=https://web.archive.org/web/20060903090534/http://www.dnr.state.md.us/dnrnews/pressrelease2005/081505.html
 |archive-date=3 September 2006
}}</ref> Several studies have shown that oysters and [[mussels]] have the capacity to dramatically alter nitrogen levels in estuaries.<ref>{{cite book |doi=10.1007/1-4020-3030-4_6 |title=The Comparative Roles of Suspension Feeders in Ecosystems, Vol. 47|year=2005|publisher=Springer|location=Netherlands|pages=93–120|author1=Newell, R. I. E.|author2=Fisher, T. R.|author3=Holyoke, R. R. |author4=Cornwell, J. C.|series=NATO Science Series IV: Earth and Environmental Series |isbn=978-1-4020-3030-7 |edition=NATO Science Series IV: Earth and Environmental Sciences|contribution=Influence of eastern oysters on nitrogen and phosphorus regeneration in the Chesapeake Bay, USA|editor1=Dame, R.|editor2=Olenin, S.}}</ref><ref>{{cite book |chapter-url=http://dx.doi.org/10.1016/S1875-306X(07)80017-7 |author1=Grabowski, J. H.|author2=Petersen, C. H.|title=Ecosystem Engineers – Plants to Protists |chapter=Restoring oyster reefs to recover ecosystem services|series=Theoretical Ecology Series |year=2007|volume=4 |publisher=Elsevier-Academic Press|location=Amsterdam|pages=281–298|doi=10.1016/S1875-306X(07)80017-7 |isbn=978-0-12-373857-8 |edition=Ecosystem Engineers: Concepts, Theory and Applications|editor1=Cuddington, K.|editor2=Byers, J. E.|editor3=Wilson, W.G.|editor4=Hastings, A.}}</ref><ref>{{cite web|vauthors=Rose JM, Tedesco M, Wikfors GH, Yarish C |title=International Workshop on Bioextractive Technologies for Nutrient Remediation Summary Report|url=http://www.nefsc.noaa.gov/nefsc/publications/|publisher=US Dept Commer, Northeast Fish Sci Cent Ref Doc. 10–19; 12 p. Available from: National Marine Fisheries Service, 166 Water Street, Woods Hole, Massachusetts 02543-1026|year=2010}}</ref> In the U.S., [[Delaware]] is the only East Coast state without aquaculture, but making aquaculture a state-controlled industry of leasing water by the acre for commercial harvesting of shellfish is being considered.<ref name="Brown">{{cite news|last=Brown|first=Ashton|title='Aquaculture' shellfish harvesting bill moves forward|url=http://delaware.newszap.com/centraldelaware/123124-70/aquaculture-shellfish-harvesting-bill-moves-forward|access-date=11 June 2013|newspaper=Delaware State News|date=10 June 2013|url-status=dead|archive-url=https://web.archive.org/web/20131022225000/http://delaware.newszap.com/centraldelaware/123124-70/aquaculture-shellfish-harvesting-bill-moves-forward|archive-date=22 October 2013}}</ref> Supporters of Delaware's legislation to allow oyster aquaculture cite revenue, job creation, and nutrient cycling benefits. It is estimated that {{convert|1|acre|ha|spell=in}} can produce nearly 750,000 oysters, which could filter between {{convert|57000|to(-)|150000|m3|e6ft3|sigfig=2|abbr=unit}} of water daily.<ref name="Brown"/> Also see [[nutrient pollution]] for an extended explanation of [[Nutrient pollution#Nutrient remediation|nutrient remediation]].

== Ecosystem services ==
As an [[ecosystem engineer]], oysters provide supporting [[ecosystem services]], along with provisioning, regulating and cultural services. Oysters influence [[nutrient cycling]], [[water filtration]], habitat structure, [[biodiversity]], and [[food web]] dynamics.<ref>{{cite journal |last1=Schulte |first1=David M. |last2=Burke |first2=Russell P. |last3=Lipcius |first3=Romuald N. |year=2009 |title=Unprecedented Restoration of a Native Oyster Metapopulation |journal=Science |volume=325 |issue=5944 |pages=1124–1128 |bibcode=2009Sci...325.1124S |doi=10.1126/science.1176516 |pmid=19644073 |s2cid=206521248|doi-access=free }}</ref> Oyster reef habitats have been recognized as [[green infrastructure]] for shoreline protection.<ref>{{Cite journal |last1=Arkema |first1=Katie K. |last2=Guannel |first2=Greg |last3=Verutes |first3=Gregory |last4=Wood |first4=Spencer A. |last5=Guerry |first5=Anne |last6=Ruckelshaus |first6=Mary |last7=Kareiva |first7=Peter |last8=Lacayo |first8=Martin |last9=Silver |first9=Jessica M. |date=14 July 2013 |title=Coastal habitats shield people and property from sea-level rise and storms |url=http://dx.doi.org/10.1038/nclimate1944 |journal=Nature Climate Change |volume=3 |issue=10 |pages=913–918 |doi=10.1038/nclimate1944 |bibcode=2013NatCC...3..913A |issn=1758-678X|url-access=subscription }}</ref> Assimilation of nitrogen and phosphorus into shellfish tissues provides an opportunity to remove these nutrients from the water column.<ref name="autogenerated1">{{cite book |last1=Wikfors |first1=Gary H. |title=Shellfish Aquaculture and the Environment |year=2011 |isbn=978-0-8138-1413-1 |pages=125–133 |chapter=Trophic Interactions Between Phytoplankton and Bivalve Aquaculture |doi=10.1002/9780470960967.ch5 |chapter-url=https://doi.org/10.1002/9780470960967.ch5}}</ref><ref>Officer, C.B., T.J. Smayda & R. Mann. 1982. Benthic filter feeding, a natural eutrophication control. Marine Ecology Progress Series. 9:203–120.</ref><ref>{{cite journal |last1=Lindahl |first1=Odd |last2=Hart |first2=Rob |last3=Hernroth |first3=Bodil |last4=Kollberg |first4=Sven |last5=Loo |first5=Lars-Ove |last6=Olrog |first6=Lars |last7=Rehnstam-Holm |first7=Ann-Sofi |last8=Svensson |first8=Jonny |last9=Svensson |first9=Susanne |last10=Syversen |first10=Ulf |year=2005 |title=Improving Marine Water Quality by Mussel Farming: A Profitable Solution for Swedish Society |url=https://doi.org/10.1579/0044-7447-34.2.131 |journal=Ambio: A Journal of the Human Environment |volume=34 |issue=2 |pages=131–138 |doi=10.1579/0044-7447-34.2.131 |pmid=15865310 |bibcode=2005Ambio..34..131L |s2cid=25371433|url-access=subscription }}</ref> In California's [[Tomales Bay]], native oyster presence is associated with higher species diversity of benthic invertebrates.<ref>{{cite journal |last1=Kimbro |first1=D. L. |last2=Grosholz |first2=E. D. |year=2006 |title=Disturbance influences oyster community richness and evenness, but not diversity |journal=Ecology |volume=87 |issue=9 |pages=2378–2388 |doi=10.1890/0012-9658(2006)87[2378:diocra]2.0.co;2 |pmid=16995638}}</ref><ref>{{cite journal |last1=Camara |first1=Mark D. |last2=Vadopalas |first2=Brent |year=2009 |title=Genetic Aspects of Restoring Olympia Oysters and Other Native Bivalves: Balancing the Need for Action, Good Intentions, and the Risks of Making Things Worse |journal=Journal of Shellfish Research |volume=28 |pages=121–145 |doi=10.2983/035.028.0104 |s2cid=12695460}}</ref> As the ecological and economic importance of oyster reefs has become more acknowledged, restoration efforts have increased.<ref name="jud and layman2">{{cite web |last1=Jud |first1=Zachary |last2=Layman |first2=Craig |year=2011 |title=Loxahatchee River oyster reef restoration monitoring report: Using baselines derived from long-term monitoring of benthic community structure on natural oyster reefs to assess the outcome of large-scale oyster reef restoration |url=https://loxahatchee-qnewmedia.netdna-ssl.com/pdf/FIU_NOAAMonitRpt_2011.pdf |url-status=dead |archive-url=https://web.archive.org/web/20220808180240/https://loxahatchee-qnewmedia.netdna-ssl.com/pdf/FIU_NOAAMonitRpt_2011.pdf |archive-date=8 August 2022 |access-date=14 July 2022 |work=Martin County, Florida}}</ref>

==Human history==
[[File:Osias Beert the Elder - Dishes with Oysters, Fruit, and Wine - Google Art Project.jpg|thumb|left|''Dishes with Oysters, Fruit, and Wine'', a 1620s painting by [[Osias Beert]]<ref>{{cite web |url=https://www.nga.gov/collection/art-object-page.91389.html |title=Dishes with Oysters, Fruit, and Wine |work=National Gallery of Art |access-date=28 October 2018}}</ref>]]
[[Midden]]s testify to the prehistoric importance of oysters as food, with some middens in [[New South Wales]], Australia, dated at ten thousand years.<ref name="dpi-oyster-industry-in-nsw">{{cite web
 |url         = http://www.dpi.nsw.gov.au/fisheries/aquaculture/publications/oysters/industry/oyster-industry-in-nsw
 |title       = Oyster industry in NSW
 |website     = NSW Department of Primary Industries
 |publisher   = NSW Government
 |access-date = 20 December 2015
|url-status     = dead
 |archive-url  = https://web.archive.org/web/20151222111017/http://www.dpi.nsw.gov.au/fisheries/aquaculture/publications/oysters/industry/oyster-industry-in-nsw
 |archive-date = 22 December 2015
}}</ref> They have been cultivated in Japan from at least 2000 BC.<ref name="dpi-oyster-industry-in-nsw" /> In the United Kingdom, the town of [[Whitstable]] is noted for oyster farming from beds on the [[Kentish Flats]] that have been used since [[Roman Britain|Roman]] times. The borough of [[Colchester]] holds an annual [[Oyster Feast]] each October, at which "Colchester Natives" (the native oyster, ''[[Ostrea edulis]]'') are consumed. The United Kingdom hosts several other annual oyster festivals; for example, [[Woburn Oyster Festival]] is held in September. In fact, in Victorian England, it was quite common for people to go to the pub and enjoy their favorite beer with some oysters. They quickly realized that the "rich, sweet, malty stouts" were great with the "briny, creamy oyster". Then brewers found that oyster shells naturally clarify a beer and they started putting crushed oyster shells into their brews. The first known brewery to start this was in 1938 at the Hammerton Brewery in London. That is where the [[oyster stout]] was first started.<ref>{{cite web |title=10 pearls of wisdom about the opulent oyster |url=https://www.bbc.co.uk/programmes/articles/1RSGcC6vq2N93c52vBqxqfC/10-pearls-of-wisdom-about-the-opulent-oyster |website=BBC |access-date=2 December 2021}}</ref>

The [[France|French]] seaside resort of [[Cancale]] in [[Brittany]] is noted for its oysters, which also date from Roman times. [[Sergius Orata]] of the [[Roman Republic]] is considered the first major merchant and cultivator of oysters. Using his considerable knowledge of [[hydraulic]]s, he built a sophisticated cultivation system, including channels and locks, to control the [[tides]]. He was so famous for this, the Romans used to say he could breed oysters on the roof of his house.<ref>{{cite book
|title=Rubicon
|author=Holland, Tom
|year=2003
|publisher=Doubleday
|isbn=978-0-385-50313-6
|url-access=registration
|url=https://archive.org/details/rubicon00tomh
}}</ref>

[[File:Alexander Adriaenssen - Still-Life with Oysters - WGA0035.jpg|thumb|Still-Life with Oysters by [[Alexander Adriaenssen]] ]]

In the early 19th century, oysters were cheap and mainly eaten by the [[working class]]. Throughout the 19th century, [[Oysters in New York City|oyster beds]] in [[New York Harbor]] became the largest source of oysters worldwide. On any day in the late 19th century, six million oysters could be found on barges tied up along the city's waterfront. They were naturally quite popular in [[New York City]], and helped initiate the city's restaurant trade.<ref name="Kurlansky, Mark 2006">{{cite book
|last=Kurlansky |first=Mark
|author-link = Mark Kurlansky
|year=2006
|title=The Big Oyster: History on the Half Shell
|publisher=Ballantine Books
|isbn=978-0-345-47638-8
|location=New York
|title-link=The Big Oyster: History on the Half Shell
}}</ref> New York's oystermen became skilled cultivators of their beds, which provided employment for hundreds of workers and nutritious food for thousands. Eventually, rising demand exhausted many of the beds. To increase production, they introduced foreign species, which brought disease; [[water pollution|effluent]] and increasing sedimentation from erosion destroyed most of the beds by the early 20th century. Oysters' popularity has put ever-increasing demands on wild oyster stocks.<ref>{{cite book
|last=Clover |first=Charles
|year=2004
|title=The End of the Line: How overfishing is changing the world and what we eat
|publisher=Ebury Press
|location=London
|isbn=978-0-09-189780-2
}}</ref> This scarcity increased prices, converting them from their original role as working-class food to their current status as an expensive delicacy.

In Britain, the native species (''[[European flat oyster]]'') has five years to mature and is protected by the people during their May-to-August spawning season. The current market is dominated by the larger [[Pacific oyster]] and [[Rock oyster]] species which are farmed year-round.

===Fishing from the wild===
[[File:Whaleback Shell Midden gully - 20070722 07986.JPG|thumb|right|The [[Whaleback Shell Midden]] in [[Maine]] contains the shells from oysters harvested for food dating from 2200 to 1000 years ago|alt=Photo of woodland stream with oyster shells covering the streambed]]
Oysters are harvested by simply gathering them from their beds. In very shallow waters, they can be gathered by hand or with small [[rake (tool)|rakes]]. In somewhat deeper water, long-handled rakes or oyster [[tongs]] are used to reach the beds. [[Patent tong]]s can be lowered on a line to reach beds that are too deep to reach directly. In all cases, the task is the same: the [[Watermen|oysterman]] scrapes oysters into a pile, and then scoops them up with the rake or tongs.

In some areas, a [[scallop dredge]] is used. This is a toothed bar attached to a chain bag. The dredge is towed through an oyster bed by a boat, picking up the oysters in its path. While dredges collect oysters more quickly, they heavily damage the beds, and their use is highly restricted. Until 1965, [[Maryland]] limited dredging to [[sailboat]]s, and even since then motor boats can be used only on certain days of the week. These regulations prompted the development of specialized [[sailboat]]s (the [[bugeye (boat)|bugeye]] and later the [[skipjack (boat)|skipjack]]) for dredging.

Similar laws were enacted in Connecticut before World War I and lasted until 1969. The laws restricted the harvesting of oysters in state-owned beds to vessels under sail. These laws prompted the construction of the oyster sloop-style vessel to last well into the 20th century. [[Hope (sloop)|''Hope'']] is believed to be the last-built Connecticut oyster sloop, completed in 1948.

Oysters can also be collected by [[underwater diving|divers]].

In any case, when the oysters are collected, they are sorted to eliminate dead animals, bycatch (unwanted catch), and debris. Then they are taken to market, where they are either canned or sold live.

===Cultivation===

[[File:Oyster culture in Belon, France 03.jpg|thumb|left|Oyster culture in [[Riec-sur-Belon]], [[France]]|alt=Oysterman standing in shallow water examining row of oyster cages that stand two feet, or 60 cm, above the water]]
{{Main|Oyster farming}}
Oysters have been cultured since at least the days of the [[Roman Empire]]. The [[Pacific oyster]] (''Magallana gigas'') is presently the most widely grown bivalve around the world.<ref>{{Cite web|url=http://www.fao.org/fishery/species/3514/en|title=FAO Fisheries & Aquaculture – Aquatic species|website=www.fao.org}}</ref> Two methods are commonly used, release and bagging. In both cases, oysters are cultivated onshore to the size of spat, when they can attach themselves to a substrate. They may be allowed to mature further to form "seed oysters". In either case, they are then placed in the water to mature. The release technique involves distributing the spat throughout existing oyster beds, allowing them to mature naturally to be collected like wild oysters. Bagging has the cultivator putting spat in racks or bags and keeping them above the bottom. Harvesting involves simply lifting the bags or rack to the surface and removing the mature oysters. The latter method prevents losses to some predators, but is more expensive.<ref>{{cite web
 |url         = http://www.lamer.lsu.edu/classroom/edonahalfshell/pdf/cycle_info.pdf
 |title       = Oyster Farming in Louisiana
 |publisher   = [[Louisiana State University]]
 |access-date  = 16 January 2008
 |url-status     = dead
 |archive-url  = https://web.archive.org/web/20071201091053/http://www.lamer.lsu.edu/classroom/edonahalfshell/pdf/cycle_info.pdf
 |archive-date = 1 December 2007
}}</ref>

The Pacific oyster has been grown in the outflow of [[mariculture]] ponds. When fish or [[prawn]]s are grown in ponds, it takes typically {{convert|10|kg|lb|abbr=on}} of feed to produce {{convert|1|kg|lb|frac=4|abbr=on}} of product ([[dry-dry]] basis). The other {{convert|9|kg|lb|abbr=on}} goes into the pond and after mineralization, provides food for phytoplankton, which in turn feeds the oyster.

To prevent spawning, sterile oysters are now cultured by crossbreeding [[tetraploid]] and [[diploid]] oysters. The resulting [[triploid]] oyster cannot propagate, which prevents introduced oysters from spreading into unwanted habitats.<ref>{{cite journal
|title= Farming triploid oysters
|author= Nell J. A.
|journal= Aquaculture
|volume=210
|issue= 1–4
|year=2002
|pages= 69–88
|doi=10.1016/S0044-8486(01)00861-4|bibcode= 2002Aquac.210...69N
}}</ref>

===Restoration and recovery===
[[File:Oyster shells.jpg|thumb|Collected Oyster Shells at [[Galveston Bay]] for restoration project by the Galveston Bay Foundation's Oyster Shell Recycling Program]]
{{Main|Oyster reef restoration}}

In many areas, non-native oysters have been introduced in attempts to prop up failing harvests of native varieties. For example, the [[eastern oyster]] (''Crassostrea virginica'') was introduced to California waters in 1875, while the Pacific oyster was introduced there in 1929.<ref>{{cite web
|url=http://aqua.ucdavis.edu/dbweb/outreach/aqua/ASAQ-A07.PDF
|title=California Oyster Culture
|publisher=[[University of California, Davis]] Department of Animal Science
|author=Conte, Fred S.
|access-date=16 January 2008
|archive-url = https://web.archive.org/web/20071201091053/http://aqua.ucdavis.edu/dbweb/outreach/aqua/ASAQ-A07.PDF |archive-date = 1 December 2007}}</ref> Proposals for further such introductions remain controversial.

The Pacific oyster prospered in [[Pendrell Sound]], where the surface water is typically warm enough for spawning in the summer. Over the following years, spat spread out sporadically and populated adjacent areas. Eventually, possibly following adaptation to the local conditions, the Pacific oyster spread up and down the coast and now is the basis of the North American west coast oyster industry. Pendrell Sound is now a reserve that supplies spat for cultivation.<ref>{{cite web
|url=http://bcsga.ca/?page_id=110
|title=Shellfish Tenures Locations Map
|access-date=16 January 2008
|archive-date=19 November 2007
|archive-url=https://web.archive.org/web/20071119105404/http://bcsga.ca/?page_id=110
|url-status=dead
}}</ref>
Near the mouth of the [[Great Wicomico River]] in the [[Chesapeake Bay]], five-year-old [[artificial reef]]s now harbor more than 180 million native ''[[Crassostrea virginica]]''. That is far lower than in the late 1880s, when the bay's population was in the billions, and watermen harvested about {{convert|910000|m3|e6impbsh|abbr=unit}} annually. The 2009 harvest was less than {{convert|7300|m3|impbsh|abbr=on}}. Researchers claim the keys to the project were:
* using waste oyster shells to elevate the reef floor {{convert|25|-|45|cm|in|abbr=on}} to keep the spat free of bottom sediments
* building larger reefs, ranging up to {{convert|8.1|ha|acre|frac=4|abbr=on}} in size
* disease-resistant broodstock<ref name=ches180>{{cite news|url=https://www.nytimes.com/2009/08/04/science/04oyster.html |title= Oysters Are on the Rebound in the Chesapeake Bay |last=Fountain |first=Henry |newspaper=The New York Times |date= 3 August 2009 |access-date=25 August 2009}}</ref>

The "oyster-tecture" movement <!--espoused by Assistant Professor Kate Orff of the Columbia University Graduate School of Architecture, -->promotes the use of oyster reefs for water purification and wave attenuation.  <!--As of 2011, coverage of the Gowanus Canal Parade of Oyster Spats is unavailable.<ref>{{cite web|author=GrrlScientist |url=https://www.theguardian.com/science/punctuated-equilibrium/2011/feb/03/1 |title=Oyster-tecture: Reviving New York City's rivers with oysters |work=The Guardian |date=3 February 2011 |access-date=16 August 2011}}</ref>--> An oyster-tecture project has been implemented at Withers Estuary, Withers Swash, South Carolina, by Neil Chambers-led volunteers, at a site where pollution was affecting beach tourism.<ref>{{Cite news|url=http://dirt.asla.org/2011/02/24/oyster-tecture-in-action/|title=Oyster-Tecture in Action|date=24 February 2011|work=THE DIRT|access-date=12 December 2017|language=en-US|archive-date=14 April 2013|archive-url=https://archive.today/20130414064516/http://dirt.asla.org/2011/02/24/oyster-tecture-in-action/|url-status=dead}}</ref> Currently, for the installation cost of $3000, roughly 4.8 million liters of water are being filtered daily. In New Jersey, however, the Department of Environmental Protection refused to allow oysters as a filtering system in Sandy Hook Bay and the Raritan Bay, citing worries that commercial shellfish growers would be at risk and that members of the public might disregard warnings and consume tainted oysters. New Jersey Baykeepers responded by changing their strategy for utilizing oysters to clean up the waterway, by collaborating with Naval Weapons Station Earle. The Navy station is under 24/7 security and therefore eliminates any [[poaching]] and associated human health risk.<ref>{{Cite web|url=http://www.nynjbaykeeper.org/index.php?option=com_content&view=article&id=61&Itemid=68|title=NY/NJ Baykeeper {{!}} Protect, Preserve, Restore|website=www.nynjbaykeeper.org|language=en-US|access-date=12 December 2017}}</ref> Oyster-tecture projects have been proposed to protect coastal cities, such as New York, from the threat of rising sea levels due to [[climate change]].<ref>{{Cite news|url=http://www.scapestudio.com/projects/oyster-tecture/|title=Oyster-tecture – SCAPE|work=SCAPE|access-date=12 December 2017|language=en-US}}</ref> Additionally, [[oyster reef restoration]] has shown to increase the population of oyster beds within the oceans while also conserving the biolife within the oyster reefs.

===Human impact===

The accidental or intentional [[Introduced species|introduction of species]] by humans has the potential to negatively impact native oyster populations. For example, non-native species in [[Tomales Bay]] have resulted in the loss of half of California's [[Olympia oyster]]s.<ref>{{Cite web |date=10 August 2009 |title=Invasive Species Threaten Critical Habitats, Oyster Among Victims |url=https://www.sciencedaily.com/releases/2009/07/090717121426.htm |access-date=1 November 2017 |website=ScienceDaily}}</ref> Oyster reefs occupy a small fraction of their distribution prior to mass harvesting during the last three centuries.<ref>{{Cite journal |last=Kirby |first=Michael Xavier |date=23 August 2004 |title=Fishing down the coast: Historical expansion and collapse of oyster fisheries along continental margins |journal=Proceedings of the National Academy of Sciences |volume=101 |issue=35 |pages=13096–13099 |doi=10.1073/pnas.0405150101 |pmid=15326294 |pmc=516522 |bibcode=2004PNAS..10113096K |issn=0027-8424 |doi-access=free }}</ref>

In October 2017, it was reported that [[Marine pollution#Underwater noise|underwater noise pollution]] can affect oysters as they close their shells when exposed to low [[Audio frequency|frequencies]] of sounds in [[experimental]] conditions. Oysters rely on hearing waves and currents to regulate their [[circadian rhythm]]s, and perception of weather events—such as [[rain]]—may induce [[Spawn (biology)#Molluscs|spawning]]. [[Cargo ship]]s, [[pile driver]]s, and explosions conducted underwater produce low frequencies that may be detected by oysters.<ref>{{Cite news |last=Quenqua |first=Douglas |date=25 October 2017 |title=Yes, Oysters Can 'Hear.' They Probably Wish We'd Clam Up. |work=[[The New York Times]] |url=https://www.nytimes.com/2017/10/25/science/oysters-noise-pollution.html |access-date=1 November 2017 |archive-url=https://web.archive.org/web/20171025214027/https://www.nytimes.com/2017/10/25/science/oysters-noise-pollution.html |archive-date=25 October 2017}}</ref>

Environmental stressors as a result of [[global change]] are also negatively impacting oysters around the world, with many impacts affecting molecular, physiological, and behavioral processes in species including [[Pacific oyster|''Magallana gigas.'']]<ref>{{Cite journal |last1=Ducker |first1=James |last2=Falkenberg |first2=Laura J. |date=2020 |title=How the Pacific Oyster Responds to Ocean Acidification: Development and Application of a Meta-Analysis Based Adverse Outcome Pathway |journal=Frontiers in Marine Science |language=English |volume=7 |doi=10.3389/fmars.2020.597441 |issn=2296-7745 |doi-access=free|bibcode=2020FrMaS...797441D }}</ref>

=== Shell recycling ===
Recycled oyster shells can help restore oyster reefs to provide marine life habitat that reduces flooding, and protects shorelines from storms.<ref name="auto2">{{Cite news |last=Journal |first=Kailyn Rhone &#124; Photographs by Tess Mayer for The Wall Street |title=The 'Save the Oceans' Tax Break: Recycling Oyster Shells |url=https://www.wsj.com/us-news/climate-environment/climate-save-ocean-recycled-oyster-shells-1fff9d54 |newspaper=WSJ}}</ref> Shell-recycling non-profits retrieve shells from restaurants, wash and dry them, and set them in the sun for up to a year to kill bacteria. Some states encourage shell recycling by offering tax incentives.<ref name="auto2" />

The [[Billion Oyster Project]] out of New York has a goal of engaging one million people to return a billion Oysters to the New York Harbor. The nonprofit partners with 60+ restaurants to recycle discarded oyster shells to rebuild Oyster reefs.

$5 Million was awarded to Restore America's Estuaries by the NOAA's Office of Habitat Conservation to rebuild oyster reefs in Louisiana, Florida, Alabama, and Texas to expand oyster recycling efforts and create new Oyster Recycling programs.<ref>{{Cite web |last=Fisheries |first=NOAA |date=2024-06-28 |title=Gulf Coast: Oyster Shell Recycling Key to Sustainable Seafood and Coastal Protection {{!}} NOAA Fisheries |url=https://www.fisheries.noaa.gov/feature-story/gulf-coast-oyster-shell-recycling-key-sustainable-seafood-and-coastal-protection |access-date=2025-04-01 |website=NOAA |language=en}}</ref> Along the Gulf, many communities support nonprofits that recycle oyster shells.

The Shells for Shorelines Initiative similarly collects donated oyster shells from restaurants in Southern California.<ref>{{Cite web |title=Shells for Shorelines |url=https://www.coastkeeper.org/shells-for-shorelines/ |access-date=2025-04-01 |website=Orange County Coastkeeper |language=en-US}}</ref> The shells are repurposed as part of a restoration project to restore native [[Ostrea lurida|Olympia oysters]] (Ostrea Larida) reefs, the only native oyster to the West Coast, Canada, and Alaska.<ref>{{Cite web |title=Olympia Oyster |url=https://www.coastkeeper.org/restoration/olympia-oyster/ |access-date=2025-04-01 |website=Orange County Coastkeeper |language=en-US}}</ref>

Historically, Oyster shell waste was repurposed to form [[tabby concrete]] in construction. The origins of the material is debated, but likely was developed on the Iberian Peninsula or North Africa, where it was then introduced to the Americas via colonization<ref>{{Cite web |last1=Jacksonville |first1=Mailing Address: 12713 Fort Caroline Road |last2=Us |first2=FL 32225 Phone: 904-641-7155 Contact |title=Tabby - Timucuan Ecological & Historic Preserve (U.S. National Park Service) |url=https://www.nps.gov/timu/learn/historyculture/kp_tabby.htm |access-date=2025-04-01 |website=www.nps.gov |language=en}}</ref> Tabby concrete is composed of burnt oyster shells for a source of lime and broken oyster shells as aggregate, and was a popular construction choice on the Atlantic coast until the mid 19th century.<ref name=":0">{{Cite journal |last=Idowu |first=Jola |date=2024-09-24 |title=Tapia, Tabbi, Tabique, Tabby |url=https://placesjournal.org/article/tabby-concrete-black-indigenous-history/?cn-reloaded=1 |journal=Places Journal |issue=2024 |language=en-US |doi=10.22269/240924|doi-access=free }}</ref> [[Kingsley Plantation|The Kingsley Plantation]] on Fort George Island, build by African slaves, is one of the most notable examples of tabby concrete, but it is commonly found on plantations, factories, military forts, and historical landmarks in the South.<ref name=":0" />

==As food==
[[File:European Flat Oyster.jpg|thumb|Freshly shucked [[European flat oyster]]]]

[[Jonathan Swift]] is quoted as having said, "He was a bold man that first ate an oyster".<ref>''Polite Conversations'', 1738, cited e.g. in {{cite journal
|title=Oyster Heaven
|journal=Wilmington Magazine
|date=24 November 2004
|url=http://www.starnewsonline.com/apps/pbcs.dll/article?AID=%2F20041124%2FMAGAZINE53%2F41129007%2F-1%2Fmagazine50&template=printart
|access-date=16 January 2008
|archive-date=28 September 2007
|archive-url=https://web.archive.org/web/20070928081020/http://www.starnewsonline.com/apps/pbcs.dll/article?AID=%2F20041124%2FMAGAZINE53%2F41129007%2F-1%2Fmagazine50&template=printart
|url-status=dead
}}</ref> Evidence of oyster consumption goes back into prehistory, evidenced by [[Midden#Shells|oyster middens]] found worldwide. Oysters were an important food source in all coastal areas where they could be found, and oyster [[fishery|fisheries]] were an important industry where they were plentiful. Overfishing and pressure from diseases and pollution have sharply reduced supplies, but they remain a popular treat celebrated in [[oyster festival]]s in many cities and towns.

It was once assumed that oysters were only safe to eat in months with the letter 'r' in their English and French names. This myth is based in truth, in that in the Northern Hemisphere, oysters are much more likely to spoil in the warmer months of May, June, July, and August.<ref>{{cite web |url=http://www.nefsc.noaa.gov/faq/fishfaq5b.html |title=Nefsc Fish Faq |publisher=Nefsc.noaa.gov |date=16 June 2011 |access-date=16 August 2011 |url-status=dead |archive-url=https://web.archive.org/web/20111004080442/http://www.nefsc.noaa.gov/faq/fishfaq5b.html |archive-date=4 October 2011 }}</ref> In recent years,{{Citation needed|reason=How recent? News articles citations needed|date=January 2024}} pathogens such as ''[[Vibrio parahaemolyticus]]'' have caused outbreaks in several harvesting areas of the eastern United States during the summer months, lending further credence to this belief.

===Dishes===
Oysters can be eaten on the half shell, raw, [[Smoking (food)|smoked]], [[Boiling|boiled]], [[Baking|baked]], [[Frying|fried]], [[Roasting|roasted]], [[stew]]ed, [[canning|canned]], [[Pickling|pickled]], [[Steaming|steamed]], or [[Grilling|broiled]], or used in a variety of drinks. Eating can be as simple as opening the shell and eating the contents, including juice. [[Butter]] and [[edible salt|salt]] are often added. Poached oysters can be served on toast with a cream [[roux]].<ref>{{cite book |title=Creamed Oysters and Leeks On Toast |publisher=Food and Wine |url=https://www.foodandwine.com/recipes/creamed-oysters-and-leeks-toast |access-date=30 January 2020}}</ref> In the case of [[Oysters Rockefeller]], preparation can be very elaborate. They are sometimes served on edible seaweed, such as [[brown algae]].

Care should be taken when consuming oysters. They may be eaten raw, with no dressing or with [[lemon]] juice, [[vinegar]] (most commonly [[shallot]] vinegar), or [[cocktail sauce]]. Upscale restaurants pair raw oysters with [[mignonette sauce]], which consists primarily of fresh chopped [[shallot]], mixed [[Black pepper|pepper]]corn, dry [[white wine]] and lemon juice or [[sherry vinegar]]. Raw oysters have complex flavors that vary among varieties and regions: salty, briny, buttery, metallic or fruity. The texture is soft and fleshy. North American varieties include Kumamoto and [[Yaquina Bay]] from Oregon, [[Duxbury]] and [[Wellfleet, Massachusetts|Wellfleet]] from Massachusetts, [[Malpeque Bay, Prince Edward Island|Malpeque]] from [[Prince Edward Island]], Canada, [[Blue Point, New York|Blue Point]] from Long Island, New York, [[Pemaquid, Maine|Pemaquid]] from [[Maine]], [[Rappahannock River]] and [[James River]] from Virginia, [[Chesapeake Bay|Chesapeake]] from Maryland and [[Cape May]] from New Jersey. In Connecticut they are frequently fished in [[Niantic, Connecticut|Niantic]] whose municipal symbol is a scallop shell in reference to its strong seafood culture. Variations in water salinity, alkalinity, and mineral and nutritional content influence their flavour.

<gallery mode="packed" widths="150px" heights="150px">
File:Smoked oysters in can - Massachusetts.jpg|Smoked oysters
File:Chargrilled oysters.jpg|Chargrilled oysters
File:Six steamed oysters on the half shell.jpg|Steamed Eastern oysters on the half shell
File:Virginia Beach-Catch31 Restaurant - Oysters Rockefeller.jpg|[[Oysters Rockefeller]]
File:Food (43644131025).jpg|[[Taiwan]]ese [[oyster misua]] 
File:FriedOyster.JPG|[[Oyster omelette]] from [[Singapore]]. Also common in [[Malaysia]]<ref>{{cite web|title=Fried Oyster|url=http://www.bestmalaysianfood.com/fried-oyster/|website=Best Malaysian Food Guide|access-date=24 July 2015|archive-date=25 July 2015|archive-url=https://web.archive.org/web/20150725011318/http://www.bestmalaysianfood.com/fried-oyster/|url-status=dead}}</ref> and throughout [[Southeast Asia]] and [[Taiwan]]
File:"Fine de Claire" raw oysters.jpg|Raw "Fine de Claire" oysters at [[Market of San Miguel|Mercado de San Miguel]] in [[Madrid]]
File:Cutlet Oysters in Hong Kong Japanese Restaurant.jpg|Japanese ''[[kaki furai]]''<ref>{{Cite web|url=https://www3.nhk.or.jp/nhkworld/en/radio/cooking/20200228.html|title=Let's Cook Japanese – Kaki Furai (Oysters Deep-Fried in Breadcrumbs)|date=2020-02-28|access-date=2021-08-21|website=NHK World-Japan|publisher=[[NHK]]}}</ref>
File:20200718 163109 Oyster dish, TaiBei ChuanQi Reastaurant Qingdao anagoria.jpg|Chinese oysters with garlic and peppers
</gallery>

===Nutrition===
Oysters are an excellent source of [[zinc]], [[iron]], [[calcium]], and [[selenium]], as well as [[vitamin A]] and [[vitamin B12|vitamin B<sub>12</sub>]]. Oysters are low in [[food energy]]; one dozen raw oysters provides only {{convert|110|kcal|kJ|order=flip|abbr=off}}.<ref>{{cite web|url=http://www.nutritiondata.com/facts/finfish-and-shellfish-products/4189/2 |title=Nutrition Facts and Analysis for Mollusks, oyster, eastern, wild, raw |publisher=Nutritiondata.com |access-date=16 August 2011}}</ref> They are rich in protein (approximately 9&nbsp;g in 100&nbsp;g of Pacific oysters).<ref>{{cite web|url=http://recipeofhealth.com/nutrition-calories/oyster-pacific-3753rb |title=Calories in pacific Oyster |publisher=Recipeofhealth.com |date=28 March 2015}}</ref> Two oysters ({{convert|28|g|oz|0|abbr=off|disp=or}}) provide the [[Reference Daily Intake]] of zinc and vitamin B<sub>12</sub>.<ref>{{cite web |url=https://nutritioncalculator.net/compare?food=337923+135419+2 |title=Nutrients for 2 oyster, NFS, raw (28 g) Oysters, raw |publisher=nutritioncalculator.net |access-date=22 March 2020 |archive-date=22 March 2020 |archive-url=https://web.archive.org/web/20200322124340/https://nutritioncalculator.net/compare%3Ffood%3D337923%2B135419%2B2 |url-status=dead }}</ref>

Traditionally, oysters are considered to be an [[aphrodisiac]], partially because they resemble female sex organs.<ref>{{cite book
|last = Stott
|first = Rebecca
|year = 2004
|url = {{google books |plainurl=y |id=3qx2ELi_ro}}
|title = Oyster
|publisher = The University of Chicago Press
|access-date = 16 January 2008
|isbn = 978-1-86189-221-8
}}{{Dead link|date=March 2023 |bot=InternetArchiveBot |fix-attempted=yes }}</ref> A team of American and Italian researchers analyzed bivalves and found they were rich in amino acids that trigger increased levels of [[sex hormone]]s.<ref>{{cite news| url=https://www.smh.com.au/articles/2005/03/23/1111525227607.html | work=The Sydney Morning Herald | title=Pearly wisdom: oysters are an aphrodisiac | date=24 March 2005}}</ref> Their high [[zinc]] content aids the production of testosterone.<ref name="Kurlansky, Mark 2006"/>

===Shucking oysters===
[[File:Couteau à huitre - coté.jpg|thumb|Special knives for opening live oysters, such as this one, have short and stout blades.]]
[[Zora Neale Hurston]] wrote, "No, I do not weep at the world--I am too busy sharpening my oyster knife."<ref>{{Cite web |title=African American Poetry: Zora Neale Hurston, "How It Feels to Be Colored Me" (1928) |url=https://scalar.lehigh.edu/african-american-poetry-a-digital-anthology/zora-neale-hurston-how-it-feels-to-be-colored-me-1928 |access-date=2025-04-01 |website=African American Poetry: A Digital Anthology |language=en}}</ref> She references the special knives for opening live oysters, referred to as "oyster-shucking." The preferred method is to use a special knife (called an [[oyster knife]], a variant of a [[shucking knife]]), with a short and thick blade about {{convert|5|cm|in|0|abbr=on}} long.

While different methods are used to open an oyster (which sometimes depend on the type), the following is one commonly accepted oyster-shucking method.
* Insert the blade, with moderate force and vibration if necessary, at the hinge between the two valves.
* Twist the blade until there is a slight pop.
* Slide the blade upward to cut the adductor muscle which holds the shell closed.

Inexperienced shuckers can apply too much force, which can result in injury if the blade slips. Heavy gloves, sometimes sold as [[oyster glove]]s, are recommended; apart from the knife, the shell itself can be razor-sharp. Professional shuckers require fewer than three seconds to open the shell.<ref name="Kurlansky, Mark 2006"/>

If the oyster has a particularly soft shell, the knife can be inserted instead in the "sidedoor", about halfway along one side where the oyster lips widen with a slight indentation.

Oyster-shucking has become a competitive sport; competitions are staged around the world.<ref>{{cite news |last1=Mateer |first1=Noelle |title=Competitive Oyster Shucking Is Real, Decadent, And China's Best Party |url=https://deadspin.com/competitive-oyster-shucking-is-real-decadent-and-chin-1838038792 |access-date=24 September 2022 |work=[[Deadspin]] |date=11 September 2019 |language=en-us}}</ref> The Guinness World Oyster Opening Championship was held annually in September at the [[Galway International Oyster Festival]], in [[Galway]], Ireland until 2010.<ref name="Independent2010">{{Cite web|url=https://www.independent.ie/entertainment/music/clodagh-gets-a-real-taste-of-the-festival-atmosphere-26684390.html|title=Clodagh gets a real taste of the festival atmosphere|date=27 September 2010|access-date=18 September 2021|website=[[Irish Independent]]|last=Melia|first=Paul}}</ref> Since 2011, "Guinness" has been dropped from the title.<ref name="GIOF_world">Comparison of archived title of the game:
* {{Cite web|url=http://www.galwayoysterfest.com/guinness-oyster-opening-championship.html|title=Guinness World Oyster Opening Championship|access-date=18 September 2021|website=Galway Oyster Festival|archive-url=https://web.archive.org/web/20100923225022/http://www.galwayoysterfest.com/guinness-oyster-opening-championship.html|archive-date=23 September 2010|url-status=dead}}
* {{Cite web|url=http://www.galwayoysterfest.com/guinness-oyster-opening-championship.html|title=Bollinger World Oyster Opening Championship – Craobhchomórtas Domhanda Oscailt Oisrí|access-date=18 September 2021|website=Galway Oyster Festival|archive-url=https://web.archive.org/web/20111017000323/http://www.galwayoysterfest.com/guinness-oyster-opening-championship.html|archive-date=17 October 2011|url-status=dead}}
* {{Cite web|url=http://www.galwayoysterfest.com/guinness-oyster-opening-championship.html|title=World Oyster Opening Championship – Craobhchomórtas Domhanda Oscailt Oisrí|access-date=18 September 2021|website=Galway Oyster Festival|archive-url=https://web.archive.org/web/20131221222715/http://www.galwayoysterfestival.com/en/Irish-Food-Festival-festival-schedule-galway-oyster-festival-food-festival-galway-ireland-irish-oysters/oyster-olympics-oyster-opening-championship.html|archive-date=21 December 2013|url-status=dead}}</ref>

===Food safety and storage===
{{more citations needed section|date=January 2020}}

Unlike most shellfish, oysters can have a fairly long shelf life of up to four weeks. However, their taste becomes less pleasant as they age. Fresh oysters must be alive just before consumption or cooking.<ref>{{Cite web|url=https://www.huffingtonpost.co.uk/entry/raw-oysters-still-alive_n_592582f3e4b0ec129d31130b?guccounter=1&guce_referrer=aHR0cHM6Ly93d3cuZ29vZ2xlLmNvbS8&guce_referrer_sig=AQAAAN1Qwcq5YAxeC2vCtI6h3MYWrFZsLRea7pQ5IF1xkki-5KutvD3zeZYD6rgEr84iP1mZsCSh3St-1ZYKvB9tQDL354Je7m-PPLPPSIKp4pWVFaWegWWeF2zGnVwh4-RO07U9Evep4CoSQDNotxPHR4-k191Z3PJiFpu8opkz6U6B|title=Raw Oysters Are Alive Until You Eat Them, In Case You Didn't Know|last=Thomson|first=Julie|date=25 May 2017|website=HuffPost}}</ref>

Cooked oysters that do not open are generally assumed to be previously dead and therefore unsafe.<ref>{{cite web |url=http://safeoysters.uga.edu/consumers/cooking.html |title=Safely Cooking Oysters and Other Molluscan Shellfish |publisher=SafeOysters.org |date=9 March 2009 |access-date=13 June 2015 |archive-url=https://web.archive.org/web/20150615144635/http://safeoysters.uga.edu/consumers/cooking.html |archive-date=15 June 2015 |url-status=dead }}</ref> There is only one criterion: the oyster must be capable of tightly closing its shell.{{Citation needed|date=June 2019}} Open oysters should be tapped on the shell; a live oyster will close up and is safe to eat.{{Citation needed|date=June 2019}} Oysters which are open and unresponsive are dead and must be discarded. Some dead oysters, or oyster shells which are full of sand, may be closed. These make a distinctive noise when tapped, and are known as "clackers".

Oysters can contain harmful [[bacteria]]. Oysters are filter feeders, so will naturally concentrate anything present in the surrounding water. Oysters from the [[Gulf Coast]] of the United States, for example, contain high bacterial loads of human pathogens in the warm months, most notably ''[[Vibrio vulnificus]]'' and ''[[Vibrio parahaemolyticus]]''. In these cases, the main danger is for [[immunocompromised]] individuals, who are unable to fight off infection and can succumb to [[sepsis]], leading to death. ''Vibrio vulnificus'' is the most deadly seafood-borne [[pathogen]].<ref>{{Cite journal|last1=Jones|first1=M. K.|last2=Oliver|first2=J. D.|date=1 May 2009|title=Vibrio vulnificus: Disease and Pathogenesis|journal=Infection and Immunity|language=en|volume=77|issue=5|pages=1723–1733|doi=10.1128/IAI.01046-08|issn=0019-9567|pmc=2681776|pmid=19255188}}</ref>

====Depuration====
[[File:Oysters in depuration tank (8535757902).jpg|thumb|left|Oysters in a [[depuration]] tank]]
[[Depuration]] of oysters is a common industry practice and widely researched in the scientific community but is not commonly known by end consumers. The main objective of seafood depuration is to remove fecal contamination in seafood before being sold to end consumers. Oyster depuration is useful since they are generally eaten raw, and in many countries the  process is government-regulated or mandatory. The [[United Nations Food and Agriculture Organization]] (FAO) formally recognizes depuration and has published detailed documents on the process,<ref>{{cite report |title=Bivalve Depuration: fundamental and practical aspects. |work=[[United Nations Food and Agriculture Organization|FAO]] |id=Fisheries Technical paper No. 511 |location=Rome |year=2008 |url=https://www.fao.org/3/i0201e/i0201e.pdf |isbn=978-92-5-106006-3 }}</ref> whereas the [[Codex Alimentarius]], encourages the application of seafood depuration.<ref>(Code of Practice for fish and fishery products (first edition) Rome 2009. WHO and FAO {{ISBN|978-92-5-105914-2}})</ref>

Oyster depuration begins after the harvest of oysters from farmed locations. The oysters are transported and placed into tanks pumped with clean water for periods of 48 to 72 hours. The holding temperatures and salinity vary according to species. The seawater that the oysters were originally farmed in does not remain in the oyster, since the water used for depuration must be fully sterilized, and the depuration facility would not necessarily be located near the farming location.<ref>{{cite journal | url=https://www.sciencedirect.com/science/article/abs/pii/S0956713513000406 | doi=10.1016/j.foodcont.2013.01.025 | title=Impact of water salinity and types of oysters on depuration for reducing Vibrio parahaemolyticus in Pacific oysters (Crassostrea gigas) | year=2013 | last1=Phuvasate | first1=Sureerat | last2=Su | first2=Yi-Cheng | journal=Food Control | volume=32 | issue=2 | pages=569–573 | url-access=subscription }}</ref> Depuration of oysters can remove moderate levels of contamination of most bacterial indicators and pathogens. Well-known contaminants include ''[[Vibrio parahaemolyticus]]'', a temperature-sensitive bacterium found in seawater animals, and ''[[Escherichia coli]]'', a bacterium found in coastal waters near highly populated cities having sewage systems discharging waste nearby, or in the presence of agricultural discharges.{{citation needed|date=July 2022}} Depuration expands beyond oysters into many shellfish and other related products, especially in seafood that is known to come from potentially polluted areas; depurated seafood is effectively a product cleansed from inside-out to make it safe for human consumption.

===Cultural aspects===
====Religious====
{{see also|Food and drink prohibitions#Crustaceans and other seafood|List of halal and kosher fish}}
As shellfish, consumption of oyster is forbidden by [[Jewish dietary law]]. Similarly, in [[Islam]], [[Jaʽfari jurisprudence|Jaʽafari]] [[Shia Islam|Shia]] and [[Hanafi]] [[Sunni Islam|Sunni]] [[Islamic dietary law|dietary jurisprudence]] prohibit consuming bivalves, including oysters, as it is ''[[makruh]]'' (highly disliked).

==Diseases==
Oysters are subject to various diseases which can reduce harvests and severely deplete local populations. Disease control focuses on containing infections and breeding resistant strains, and is the subject of much ongoing research.
* "Dermo" is caused by a [[protozoa]]n [[parasite]] (''[[Perkinsus marinus]]''). It is a prevalent [[pathogen]], causes massive mortality, and poses a significant economic threat to the oyster industry. The disease is not a direct threat to humans consuming infected oysters.<ref name="ct.gov">{{cite web
|url=https://portal.ct.gov/doag/aquaculture1/aquaculture/oyster-and-clam-diseases
|title=Oyster Diseases
|publisher=Connecticut Department of Agriculture
|access-date=16 January 2008}}</ref> Dermo first appeared in the [[Gulf of Mexico]] in the 1950s, and until 1978 was believed to be caused by a [[fungus]]. While it is most serious in warmer waters, it has gradually spread up the east coast of the United States.<ref name="chesapeakebay.net">{{cite web
 |url         = http://www.chesapeakebay.net/oysterdiseases.aspx?menuitem=19507
 |title       = MSX/Dermo
 |publisher   = Chesapeake Bay Program
 |access-date  = 5 April 2009
 |url-status     = dead
 |archive-url  = https://web.archive.org/web/20090301021004/http://www.chesapeakebay.net/oysterdiseases.aspx?menuitem=19507
 |archive-date = 1 March 2009
}}</ref>
* Multinucleated sphere X (MSX) is caused by the protozoan ''[[Haplosporidium nelsoni]]'', generally seen as a multinucleated ''[[Plasmodium]]''. It is infectious and causes heavy mortality in the [[eastern oyster]]; survivors, however, develop resistance and can help propagate resistant populations. MSX is associated with high salinity and water temperatures.<ref name="ct.gov"/> MSX was first noted in [[Delaware Bay]] in 1957, and is now found all up and down the East Coast of the United States. Evidence suggests it was brought to the US when ''[[Crassostrea gigas]]'', Pacific oyster variety, was introduced to Delaware Bay.<ref name="chesapeakebay.net"/>
* Denman Island disease causes visible yellow/green pustules on the body and adductor muscles of oysters. This disease mainly affects Pacific oysters (''[[Crassostrea gigas]]''). The disease was first described in 1960 near [[Denman Island]] off the eastern aspect of Vancouver Island, British Columbia. It was found that the causative agent of these lesions are associated with amitochondriate protistan microcells, which were later identified as ''[[Mikrocytida|Mikrocytos mackini]].''

Some oysters also harbor bacterial species which can cause human disease; of importance is ''[[Vibrio vulnificus]]'', which causes [[gastroenteritis]], which is usually self-limiting, and [[cellulitis]]. Cellulitis can be severe and rapidly spreading, requiring antibiotics, medical care, and in some severe cases amputation. It is usually acquired when the contents of the oyster come in contact with a cut skin lesion, as when shucking an oyster.

==See also==
{{cookbook|Oyster}}
{{portal|Food}}
{{columns-list|colwidth=30em|
* [[Angels on horseback]]
* [[List of smoked foods]]
* {{anl|Oyster omelette}}
* {{anl|Oyster pirate}}
* {{anl|Oyster sauce}}
* [[Oysters Kirkpatrick]]
* [[Red tide]]
* {{anl|Rolled oyster}}
* {{anl|San Leandro Oyster Beds}}
}}

==References==
{{reflist|colwidth=30em}}

==External links==
{{commons|Oyster}}
{{wikiquote|Oysters}}
{{wiktionary|oyster}}
* [http://www.molluscan-eye.com molluSCAN-eye - Online biomonitoring project hosted by the University of Bordeaux and the CNRS] A website devoted to the online study of molluscan bivalve behavior around the world, including oysters
* [https://web.archive.org/web/20110613083931/http://www.worldofboats.org/boats/view/sunny_south/117 World of Boats (EISCA) Collection ~ Fal Oyster Boat, Sunny South]
* [http://www.geographyinaction.co.uk/Assets/Photo_albums/Eleven/pages/Oysters1.html Oysters grown on trestles in Ireland] {{Webarchive|url=https://web.archive.org/web/20080517105216/http://www.geographyinaction.co.uk/Assets/Photo_albums/Eleven/pages/Oysters1.html |date=17 May 2008 }}
* [http://www.essex-family-history.co.uk/oysters.htm Oyster farming in the Rivers Crouch, Roach and Blackwater of Eastern Essex] {{Webarchive|url=https://web.archive.org/web/20090703191344/http://www.essex-family-history.co.uk/oysters.htm |date=3 July 2009 }}
* {{Cite NIE|wstitle=Oyster|short=x}}

{{Oysters}}
{{commercial molluscs}}
{{commercial fish topics}}
{{Edible molluscs}}
{{Authority control}}

[[Category:Ostreida]]
[[Category:Dishes involving the consumption of live animals]]
[[Category:Symbols of Mississippi]]
[[Category:Oysters| ]]
[[Category:Smoked food]]
[[Category:Mollusc common names]]
[[Category:Aphrodisiac foods]]
[[Category:Cuisine of New England]]
[[Category:Cuisine of the Southwestern United States]]