Radioactive Tuna Arrives to US Shores

Bluefin tuna carrying radioactive contamination that leaked from Japan's crippled nuclear plant have been caught on the shores of the United States 6,000 miles away – the first time a large migrating fish has been shown to carry radioactivity such a distance.   One of the largest and speediest fish, Pacific bluefin tuna can grow to 10 feet and weigh more than 1,000 pounds. They spawn off the Japan coast and swim east to school in waters off California and the tip of Baja California, Mexico.  The levels of radioactive cesium in the recently caught tuna were 10 times higher than the amount measured in tuna off the California coast in previous years. Daniel J. Madigan, from Stanford University (California, USA), and colleagues did not expect the nuclear fallout to linger in huge fish that sail the world because such fish can metabolize and shed radioactive substances.  Observing 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 of radionuclides,” the study authors warn that: “Other large, highly migratory marine animals make extensive use of waters around Japan, and these animals may also be transport vectors of Fukushima-derived radionuclides to distant regions of the North and South Pacific Oceans.”