The Japanese government on Tuesday set the maximum allowable level of radioactive iodine-131 at 2,000 becquerels per kilogram for fish amid growing concerns over the spread of radioactive substances from a crippled nuclear power plant in Fukushima Prefecture, northeastern Japan.
Chief Cabinet Secretary Yukio Edano announced the per-kilogram limit, which is the same as that for vegetables, at a news conference.
The government instructed all prefectural governments to prevent fish and shellfish containing iodine-131 exceeding the limit from being used for human consumption.
The decision came after 4,080 becquerels per kilogram of iodine-131 were found in small fish, called young sand lances, which was caught off Ibaraki Prefecture, south of Fukushima, on Monday.
Previously, no limit had been set for iodine-131 for fish because the radioactive material has a short half-life of about eight days and could be diluted in the ocean. For radioactive cesium, the maximum permissible level has been set at 500 becquerels per kilogram for fish under the food sanitation law.