Radioactive fish came from Fukushima: study

US researchers measured the levels of two radioactive isotopes of cesium in 15 bluefin tuna caught off the coast of San Diego, California, in August 2011.

They found that the fish contained modestly elevated levels of radioactive cesium-134 and cesium-137 whereas tuna that were not exposed to the Fukushima disaster had no measurable cesium-134 and only background levels of cesium-137.

Because cesium-134 was undetectable in Pacific Ocean seawater and marine life before the Fukushima Daiichi disaster, the findings suggested to the authors