Oyster: Farmed

Oyster

Kaki

Oysters are filter-feeding bivalves that inhabit most oceans in the world except near polar extremes. Oyster seed can be reared in hatcheries or collected from the wild, depending on technical sophistication, practicality, and tradition. Grow-out of oysters is accomplished in natural, inter-tidal or sub-tidal waters. Grow-out techniques involve suspension of oysters in the water column, via rafts or floats, or bottom culture, in which oysters are fixed to the seabed. Because oysters are filter feeders, oyster aquaculture facilities generally improve coastal water conditions by converting nutrients and organic matter to biomass.

With low use of marine resources or pollution, moderate risk of escapes or disease, and good management farmed oysters are a “Best Choice”

The combination of non-reliance on ocean resources for feed inputs as the small impact of broodstock capture on wild populations results in a ‘low’ rating.

Presently, there is no containment system in aquaculture that is 100 % effective and almost all oyster culture is conducted in open systems where there is some risk of escape, especially for non-native species of oysters; however, because oysters are non-motile, this risk is greatly reduced. Negative interactions with wild stocks, especially through competition for food and space, have been well documented.

Although there have been no identifiable pathogens yet, introductions of non-native species can pose a viable risk of disease transfer.

Chemicals used in hatchery production of polyploid oysters are minute and do not appear to cause a contamination concern. Habitat impacts and pollution effects of farmed oysters grown off-bottom in suspended culture are of ‘low’ conservation concern.

In developed, and some developing, countries there are strict regulations governing water quality and habitat change as it pertains to oyster culture. These countries have comprehensive suite of management measures deemed to be highly effective.

Are these oysters wild or farmed?

Oysters farmed using suspended culture production methods are a more sustainable choice.

Contaminant levels do not warrant a consumption advisory.

No.