Even though hatchery-cultivated Pacific oyster seed is widely used around the world, oyster seedlings are naturally collected in Japan.
Oysters are filter feeders that feed on phytoplankton. With no additional feeding needed, there is no fishing pressure on wild stock.
Oysters farms produce very low waste discharge because no external feed is required. Japan’s Pacific oyster production is mainly concentrated in two areas (Hiroshima and Miyagi), and with at least parts of its oyster farms areas overlapping with seagrass distribution, some alterations in areas of moderate ecological sensitivity may occur. Oyster farming has a high escape risk. The impact of these escapes in the environment is unknown. There is no evidence that chemicals are used on Japan’s farmed Pacific oysters.
Management system for Pacific oyster farming is partially effective in Japan. While regulations and laws are adopted, compliance and enforcement are quite poor. It lacks specific information on environmental impact assessment, monitoring activities, etc. requiring the adoption and enforcement of more effective measures.