Its distribution has been affected by habitat change; less than 1% of the population present when the first European colonists arrived is thought to remain in the Chesapeake Bay and its tributaries.

[9] As of 2014, the global conservation status of Crassostrea virginica, as assessed by NatureServe, is "vulnerable," as the oyster's populations are threatened by overharvest and water pollution.

[1] Other threats to the eastern oyster include global warming, diseases and parasites, and competition with invasive species.

[15] The eastern oyster, like all members of the family Ostreidae, can make small pearls to surround particles that enter the shell.

The specific gravity of the two types of shell is similar, so neither would confer a weight advantage over the other for a freely swimming larva.

[16] The transition to the thicker calcite shell in the adult of this species is thought to be an adaptation for defense against predators because the oysters are immobilized in exposed locations.

[19] The eastern oyster's reproductive cycle begins during late summer and autumn months with the storage of glycogen energy reserves.

[20] The gametes begin to mature in late spring and then, from June to August, they are spawned into the water column, where fertilization occurs.

[21] Fertilized eggs develop in about six hours into planktonic, free-swimming, trochophore larvae, also known as the early umbo stage, which have cilia and a small shell.

[22] They then develop within 12 to 24 hours into a fully shelled veliger larvae, also known as the late umbo stage, which has a hinged side and a velum.

Upon settling, a larva cements its left valve to the substrate and metamorphoses into an oyster spat by discarding its velum, reabsorbing its foot, and enlarging its gills.

Oysters first arrived in the Chesapeake 5,000 years ago,[citation needed] and shortly after, local Indians began eating them.

Archaeologists found evidence the local Native Americans returned to the same place to collect oysters for 3,000 years.

[26] However, the effect of overharvesting would remain local until after the Civil War, when a combination of new technologies led to the removal of nearly all the bay oysters.

During the industrial revolution, several new technologies were introduced to the Chesapeake Bay area which allowed for more intensive oyster harvesting.

And finally, the proliferation of steam-powered ships and railroads made transportation more reliable, enabling merchants to sell oysters far and wide.

Overharvesting eventually depleted the remaining oyster population in the bay to just 1% of its historical level, where it stands today.

By the 1920s, harvests were down to 3–5 million bushels per year,[26] stabilized for a time by returning oyster shells back to the bay.

The parasites which carried the disease are alien to eastern waters, and they were thought to have been brought to the Chesapeake by Asian oysters.

[29] Other regions of the East Coast of the United States have successful oyster farms, including most notably Cotuit, Martha's Vineyard and Wellfleet, Massachusetts, on Cape Cod.

Harvestable size of a C. virginica oyster is 75 mm (3.0 in), which can take from 12 to 36 months, depending on temperature, salinity of the water, and food supply.

[31] To keep the oil at bay and to spare the oystermen, the authorities of Louisiana made an unprecedented decision to maximize the fresh water flow through the region's canals to three times usual levels.

[21] Sujata Gupta ventured into the marshlands and Gulf of Mexico with Brad Robin, a man from a line of generations of oystermen in southeastern Louisiana.

[36] MSX slows the feeding rates of infected oysters, leading to a reduction in the amount of stored carbohydrates, which in turn inhibits normal gametogenesis during spawning, resulting in reduced fecundity.

The nervous system control of lateral ciliary activity of the gill of the bivalve mollusc, Crassostrea virginica.

Whole animal and gill tissue oxygen uptake in the Eastern oyster, Crassostrea virginica: Effect of hypoxia, hypercapnia, air exposure, and infection with the protozoan parasite Perkinsus marinus.