There are three ways to collect fish fry: hatchery based, hatchery-based juvenile production using wild-caught broodstock, and caught from over-exploited stock.
Clams are filter feeders. Therefore, no feed is needed. There will be no fishing pressure on wild stock.
Intertidal mudflat culture may cause moderate habitat alteration. The escape risk of farmed clam is high, but the escape impact may depend on the source of fish fry. If the fry is sourced from the wild, the escape impact may be low; if the fry is sourced from hatcheries, the escape impact may be high; if the fry is sourced from hatchery-based juvenile production using wild-caught broodstock, the escape impact may be moderate. There may be chemical use but the amount is low.
A comprehensive environmental impact assessment is lacking. China is focused on land and water use. The overall management is partly effective.