Scientists in California said on Monday that bluefin tuna had been found to contain radioactivity—carried 6,000 miles from Japan where radioactivity leaked into the waters after its nuclear crisis. “We were frankly kind of startled,” said Nicholas Fisher, one of the researchers in the National Academies of Science who reported the findings. The levels of radioactive cesium were 10 times higher than the amount in tuna off the California coast in recent years—although the levels are still well below the safe-to-eat levels set by the U.S. and Japan. One of the largest and fastest fish in the Pacific, Pacific bluefin tuna can grow to 10 feet and weigh more than 1,000 pounds. They spawn off the coast of Japan and swim at a breakneck pace to the California coast.