Worries over highly radioactive fish prompt study via The Asahi

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However, in August, two greenlings caught 20 kilometers north of the Fukushima plant were found to have cesium levels of 25,800 becquerels per kilogram, the highest level ever measured in fish since the nuclear accident. The government standard for food is 100 becquerels per kilogram.

And in March, tests recorded a level of 18,700 becquerels per kilogram in freshwater salmon in the Niidagawa river near Iitate, a village northwest of the nuclear plant.

Furthermore, the concentration of cesium in freshwater salmon and char caught since March has not been decreasing, leading to restrictions on the shipment of such fish from Fukushima Prefecture and surrounding areas.

The forthcoming study will analyze cesium levels in the fish’s otolith, a part of the inner ear. The otolith is widely used in such research because it is an organ where trace elements tend to accumulate over the animal’s lifespan, leaving a growth record that can be likened to the rings of a tree.

Researchers hope to develop an understanding of when the fish were contaminated. They will also measure cesium levels in contaminated seabed soil near the nuclear plant.

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