IITATE, Fukushima — Radioactive cesium far exceeding the allowable limit and way higher than previously detected contamination levels in fish has been found in river trout here, the prefectural government said on March 28.

The yamame, or landlocked masu salmon, caught in the Niida River in Iitate, Fukushima Prefecture, measured 18,700 becquerels of radioactive cesium per kilogram, a reading over 37 times more than the government-imposed provisional limit of 500 becquerels per kilogram.

The radiation dose detected this time exceeds the 14,400 becquerels per kilogram detected in sand eels in waters off Iwaki, Fukushima Prefecture, in April 2011, becoming the highest radiation dose found in sea and freshwater fish since the outbreak of the nuclear disaster at the Fukushima No. 1 Nuclear Power Plant in March last year.

The prefectural government has requested related fishery cooperatives to refrain from catching and eating yamame fish from the Niida River’s main current and tributaries.

The contaminated fish was caught for sampling prior to the opening of the fishing season in April this year and has not been circulated in markets.