Recently, the environment of aquaculture grounds have been worsened rapidly due to self-contamination by excessive feeding mainly, and also damages of marine living resources by disease is in serious condition. So, aquaculture policy in Japan has been concentrating on measures to address problems impeding sustainable aquaculture in coastal waters.

In last May, to ensure stable and sustainable aquaculture production through eliminating main causes of those problems, the Government of Japan has enacted new regulations to ensure sustainable aquaculture. The regulations are composed by two important measures including the improvement and preservation of aquaculture grounds, and preventing the spread of fish and shellfish disease. Under the Law, Agriculture Ministry has to establish basic guidelines which contains the targets and measures to improve aquaculture grounds and to prevent the spread of disease. Each Fishermen cooperative should follow these guidelines when they establish the plan to improve their aquaculture grounds and prevent the spread of disease. When serious fish disease outbreak in the rearing cage, fishermen should destroy the fish caught by burning.

In the case of sea surface aquaculture, it was determined that the oxygen of the sea water in the cage should be more than 4.0 ml per litre. Quantity of existing sulphide in the bottom mud immediately under cage net should be less than the oxygen available to reset with sulphide. And benthos such as lugworm should exist always in the mud under cage.