The Pacific oyster is native to Japan, but was introduced to North America in the 1920s and is now cultivated around the world using a variety of methods. Its distinctive shell is cup-shaped, giving rise to the name “Pacific cupped oyster.” These hardy shellfish prefer rocky bottoms but can live in a variety of subtidal and intertidal habitats.
Pacific oysters take four years to reach a 2.5- to 3-inch size. They create their hard shell from being exposed to the sun, wind and extremes in temperatures as the tide ebbs and floods. They have a creamy white meat with a firm texture and a robust and briny flavour. Different cultivating methods and the marine environment drastically affect the flavour, texture and appearance of Pacific oysters, allowing shellfish growers to create distinctive regional varieties.
Pacific oysters grow quickly and reproduce rapidly. They first mature and reproduce as males, then later develop into females. Spawning is seasonal and depends on water temperature. Females are very fecund, producing between 50 and 200 million eggs during. Larvae (also known as spat) disperse into the water column and eventually settle on the seafloor where they grow into adults. In proper conditions, these filter-feeders can reach market size in 1.5 to 2.5 years. Most commercial Pacific oysters are cultivated in hatcheries and farms. Shellfish growers typically purchase juvenile oysters or “seed” from hatcheries or collect wild seed from the marine environment. The seed is then taken from the hatchery to a shellfish farm or lease located in a natural marine environment like a bay or inlet. The oysters are grown using a variety of techniques: they can be placed on the seafloor, suspended in mesh bags or trays in the ocean or attached to rope and wooden frames in the intertidal zone. They are harvested when they reach the desired size.
Fishponds are a traditional method of aquaculture used to grow seaweed, shellfish and fish. Hawaiian fishponds are unique because they are built with rock into especially large walled ponds. Harvesters will construct pens to grow juvenile fish and will remove seaweed mats by hand to maintain a healthy pond.