Massive bluefin tuna have carried radioactive contamination across 6,000 miles of the Pacific Ocean to the California shores. The Pacific bluefin tuna that can grow to 10 feet and weigh more than 1,000 pounds, spawn off the Japan coast and swim east at breakneck speed to school in waters off California and the tip of Baja California, Mexico. This is the first time a large migrating fish has been shown to carry radioactivity such a long distance. The levels of radioactive cesium were 10 times higher than the amount measured in tuna off the California coast in previous years. It is important to note that these levels are still far below safe-to-eat limits set by the U.S. and Japanese governments. Previously, smaller fish and plankton were found with elevated levels of radiation in Japanese waters after the March 2011 magnitude-9 earthquake that triggered a tsunami that damaged the Fukushima Dai-ichi reactors. Scientists report that bluefin tuna absorbed radioactive cesium from swimming in contaminated waters and feeding on contaminated prey such as krill and squid.
