Oysters are filter feeders that feed on phytoplankton. With no additional feeding required, there is no fishing pressure on wild stock.
Farming filter-feeding species generates minimal amount of waste discharge. This production method will create moderate habitat alteration. The escape risk is high, but the escape impact is low as the species is already fully established in the region. The species is subject to various viral or bacterial disease outbreaks occurring regularly. No chemical is used in culturing oysters.
All issues are rated largely effective apart from environmental impact assessment. Even with legislation in place, there are still major problems associated with this issue.