Radioactive cesium 25 times above the legal limit for consumption was detected Wednesday in young sand lance caught off Fukushima Prefecture, the health ministry said.
One of the sampled fish tested for cesium had 12,500 becquerels per kg.
It was caught about 500 meters off Iwaki and 35 km from the crippled Fukushima No. 1 nuclear power station, it said. The limit for cesium is 500 becquerels under the Food Sanitation Law.