The study was authored by Daniel Madigan of California's Stanford University, and Zofia Baumann and Nicholas Fisher, from Stony Brook University in New York.
Researchers found that the 15 bluefin tuna caught off the coast of San Diego, California in August 2011, contained slightly elevated levels cesium-137 and cesium-134.
However, the researchers said that the radioactivity levels did not pose any risk to human health and were far less than the Japanese safety limit.
The study noted that the findings indicate that Pacific bluefin tuna can rapidly transport radionuclides from a point source in Japan to distant ecoregions and demonstrate the importance of migratory animals as transport vectors.
On 11 March 2011, a massive earthquake and tsunami struck Japan, affecting the cooling systems at the Fukushima plant, causing meltdowns in some of its reactors.
