The genus Magallana is named for the Portuguese explorer Ferdinand Magellan[2] and its specific epithet gígās is from the Greek for "giant".

[6][7] Parts of the scientific community resist this change and continue to argue that Crassostrea gigas should be the proper name.

[11] This species is very fecund, with females releasing about 50–200 million eggs in regular intervals (with a rate at 5–10 times a minute) in a single spawning.

[11] In males, the sperm is released at the opposite end of the oyster, along with the normal exhalent stream of water.

[10] Over these weeks, larvae can disperse great distances by water currents before they metamorphose and settle as small spat.

The genome of M. gigas has been sequenced, revealing an extensive set of genes that enables it to cope with environmental stresses.

[13] The expression of genes such as arginine kinase and cavortin is particularly important in regulating the metabolic response of this species to stress events including the reduction of seawater pH, as observed under ocean acidification.

[10] It is native to the Northwest Pacific, and occurs primarily in temperate waters between 30° N and 48° N.[15] It is now the most widely farmed and commercially important oyster in the world, as it is very easy to grow, environmentally tolerant, and easily spread from one area to another.

[10] In some places in the world, though, it is considered by biosecurity, primary industry, and conservation departments and ministries to be an invasive species, where it is outcompeting native species, such as the Olympia oyster in Puget Sound, Washington; the rock oyster, Saccostrea commercialis, in the North Island of New Zealand; and the blue mussel, Mytilus edulis, in the Wadden Sea.

[10] The seed from the wild can either be collected by the removal of seaweed from beaches or by hanging shell (cultch) in suspension from long lines in the open water.

[11] Pacific oyster broodstocks in hatcheries are kept in optimum conditions so the production of large amounts of high quality eggs and sperm can be achieved.

[10] Pacific oyster females are very fecund, and individuals of 70–100 g live weight can produce 50–80 million eggs in a single spawn.

[10] Yet, the eggs from a small sample of females (about six) are more commonly stripped from the gonads using Pasteur pipettes and fertilized by sperm from a similar number of males.

[10] Land-based nursery systems have spat mounted on barges in large saltwater tanks, which either have a natural algae supply or are enriched with nutrients from fertilizers.

[10] The technique used depends on site-specific conditions, such as tidal range, shelter, water depth, current flow, and nature of substrate.

[18] Pacific oysters are nonspecific filter feeders, which means they ingest any particulate matter in the water column.

[19] Globally, noroviruses are the most common cause of nonbacterial gastroenteritis, and are introduced into the water column by faecal matter, either from sewage discharge or land runoff from nearby farmland.

[19] Pacific oysters, like other shellfish, are able to remove heavy metals, such as zinc and copper, as well as biotoxins (microscopic toxic phytoplankton), from the surrounding water.

[27] Several crab species (Metacarcinus magister, Cancer productus, Metacarcinus gracilis), oyster drills, and starfish species (Pisater ochraceus, Pisater brevispinus, Evasterias troschelii, and Pycnopodia helianthoides) can cause severe impacts to oyster culture.

[27] Increasing numbers of frames for oysters to grow on has led to claims that the character of the beach is changed and that other users may be endangered.

[32] Early experiments in rock oyster cultivation procedures attached spat to cement-covered sticks and laid them down in racks.

[33] In 2006, the 23 Pacific oyster farms throughout New Zealand covered a total of 750 hectares of marine space and produced 2,800 tonnes of product per year.