All other members of: Oyster is the common name for a number of different families of salt-water bivalve molluscs that live in marine or brackish habitats.

[1] The French derived from the Latin ostrea, the feminine form of ostreum,[2] which is the latinisation of the Ancient Greek ὄστρεον (ostreon) 'oyster'.

Examples include: In the Philippines, a local thorny oyster species known as Tikod amo is a favorite seafood source in the southern part of the country.

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.

Chesapeake Bay's once-flourishing oyster population historically filtered excess nutrients from the estuary's entire water volume every three to four days.

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.

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.

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.

[15][16][17][18] Oysters consume nitrogen-containing compounds (nitrates and ammonia), phosphates, plankton, detritus, bacteria, and dissolved organic matter, removing them from the water.

[25] Supporters of Delaware's legislation to allow oyster aquaculture cite revenue, job creation, and nutrient cycling benefits.

It is estimated that one acre (0.40 ha) can produce nearly 750,000 oysters, which could filter between 57,000 to 150,000 m3 (2.0–5.3 million cu ft) of water daily.

[35] 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 times.

Using his considerable knowledge of hydraulics, he built a sophisticated cultivation system, including channels and locks, to control the tides.

[38] New York's oystermen became skilled cultivators of their beds, which provided employment for hundreds of workers and nutritious food for thousands.

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.

[44] Near the mouth of the Great Wicomico River in the Chesapeake Bay, five-year-old artificial reefs now harbor more than 180 million native Crassostrea virginica.

Researchers claim the keys to the project were: The "oyster-tecture" movement promotes the use of oyster reefs for water purification and wave attenuation.

New Jersey Baykeepers responded by changing their strategy for utilizing oysters to clean up the waterway, by collaborating with Naval Weapons Station Earle.

[47] 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.

[50] In October 2017, it was reported that underwater noise pollution can affect oysters as they close their shells when exposed to low frequencies of sounds in experimental conditions.

Oysters rely on hearing waves and currents to regulate their circadian rhythms, and perception of weather events—such as rain—may induce spawning.

[53] 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.

Overfishing and pressure from diseases and pollution have sharply reduced supplies, but they remain a popular treat celebrated in oyster festivals in many cities and towns.

[55] In recent years[citation needed], 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.

Upscale restaurants pair raw oysters with mignonette sauce, which consists primarily of fresh chopped shallot, mixed peppercorn, dry white wine and lemon juice or sherry vinegar.

North American varieties include Kumamoto and Yaquina Bay from Oregon, Duxbury and Wellfleet from Massachusetts, Malpeque from Prince Edward Island, Canada, Blue Point from Long Island, New York, Pemaquid from Maine, Rappahannock River and James River from Virginia, Chesapeake from Maryland and Cape May from New Jersey.

[62] A team of American and Italian researchers analyzed bivalves and found they were rich in amino acids that trigger increased levels of sex hormones.

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.

Similarly, in Islam, Jaʽafari Shia and Hanafi Sunni dietary jurisprudence prohibit consuming bivalves, including oysters, as it is makruh (highly disliked).