By . Daily Mail Reporter . PUBLISHED: . 17:46 EST, 28 May 2012 . | . UPDATED: . 12:40 EST, 29 May 2012 . If your muscles start swelling to superhero proportions after your next sushi meal, this might be why. Researchers from Stony Brook University in New York have discovered bluefin tuna are carrying radioactive contamination leaked from Japan's crippled nuclear plant all the way across the Pacific to the United States, 6,000 miles away. This is the first time a huge migrating fish has been shown to carry radioactivity such a distance, as they generally metabolise the contamination during their journey. Radioactive: Scientists said the increased radiation found in the Pacific bluefin tuna came from Japan's Fukushima nuclear plant that was crippled by the 2011 earthquake and tsunami . Nuclear: The Fukushima Dai-ichi nuclear power plant, pictured, was badly damaged in the 2011 earthquake and tsunami leading to a higher level of contamination in tuna . 'We were frankly kind of startled,' said researcher Nicholas Fisher, who reported the findings on Monday in the Proceedings of the National Academy of Sciences. The levels of contamination were 10 times higher than the amount measured in tuna off the California coast in previous years. But even so, it's still far below safe-to-eat limits set by the U.S. and Japanese governments, so is unlikely to affect humans. Since the March 2011 earthquake and subsequent tsunami that badly damaged the Fukushima Dai-ichi reactors, smaller fish and plankton have been found with elevated levels of radiation in Japanese waters. Prized: Sushi chef Kiyoshi Kimura poses next to a 269 kilogram bluefin tuna, which can fetch $24 for a thin slice at top Tokyo restaurants . But scientists did not expect the nuclear fallout to linger in huge fish such as bluefin tuna, which grow to 10 feet and weigh over 1,000 pounds. This is because they generally shed radioactive substances easily, metabolising it as they sail the world. The tuna captured off the California coast were contaminated with radioactive material from the Fukushima meltdown of March last year. When an earthquake and tsunami struck Japan, they overwhelmed the defences of the Dai-Ichi power plant, leading to the worst nuclear disaster since Chernobyl. Dangerous amounts of radioactive material were carried by wind away from the plant, which is just 30 miles from the Pacific Ocean. When those substances - such as isotopes caesium-134 and caesium-137 - entered the water, they also entered the food chain and living environment of fish such as tuna. The face that the radioactive caesium has stayed in the tuna's system a year later, even after a 6,000-mile swim across the ocean, shows just how much of the isotope was released by the meltdown. While scientists claim that the fish is currently safe to eat, many of the effects of radioactivity on the human body are still unknown. Five months after the Fukushima disaster, Fisher and his team decided to test Pacific bluefin, that spawn off the coast of Japan and swim east to California and Mexico. To their surprise, tissue samples from all 15 tuna captured off the San Diego coast contained levels of two radioactive substances - caesium-134 and caesium-137 - that were higher than in previous catches. The scientists also analysed yellowfin tuna, found in the eastern Pacific, and bluefin that migrated to Southern California before the nuclear crisis, to rule out any other causes for the enhanced radiation, such as ocean currents. They found no trace of caesium-134 and only background levels of caesium-137 left over from nuclear weapons testing in the 1960s. The results 'are unequivocal. Fukushima was the source,' said Ken Buesseler of the Woods Hole Oceanographic Institution. Bluefin tuna absorbed radioactive caesium from swimming in contaminated waters and feeding on contaminated prey such as krill and squid, the scientists said. As the predators made the journey east, they shed some of the radiation through metabolism and as they grew larger. Even so, they weren't able to completely flush out all the radioactivity from their system. 'That's a big ocean. To swim across it and still retain these radionuclides is pretty amazing,' Fisher said. Debris: Radioactive tuna is not the only casualty of the tsunami to wash up in North America, as this motorbike which found its way from Japan to Canada proves . Can I have my ball back, please? Another Japanese visitor to the U.S. is a football owned by Misaki Murakami, left, and found by David Baxter, right, on a beach in Alaska . Pacific bluefin tuna are prized in Japan where a thin slice of the tender red meat prepared as sushi can fetch $24 per piece at top Tokyo restaurants. Japan consumes 80 per cent of the world's Pacific and Atlantic bluefin tuna. But researchers say the real test of how radioactivity affects tuna populations comes this summer when they plan to repeat the study with a larger number of samples. Bluefin tuna that journeyed last year were exposed to radiation for about a month but the upcoming travelers have been swimming in radioactive waters for a longer period. They are also keen to track the movements of other migratory species including sea turtles, sharks and seabirds, now they know bluefin tuna can transport radiation.
Pacific tuna has radiation levels 10 times higher than normal .
Radioactivity has remained in system on 6,000-mile swim from Japan to U.S.
Scientists claim fish should still be safe for people to eat as radiation remains below legal limit .
By . Daily Mail Reporter . PUBLISHED: . 17:46 EST, 28 May 2012 . | . UPDATED: . 12:40 EST, 29 May 2012 . If your muscles start swelling to superhero proportions after your next sushi meal, this might be why. Researchers from Stony Brook University in New York have discovered bluefin tuna are carrying radioactive contamination leaked from Japan's crippled nuclear plant all the way across the Pacific to the United States, 6,000 miles away. This is the first time a huge migrating fish has been shown to carry radioactivity such a distance, as they generally metabolise the contamination during their journey. Radioactive: Scientists said the increased radiation found in the Pacific bluefin tuna came from Japan's Fukushima nuclear plant that was crippled by the 2011 earthquake and tsunami . Nuclear: The Fukushima Dai-ichi nuclear power plant, pictured, was badly damaged in the 2011 earthquake and tsunami leading to a higher level of contamination in tuna . 'We were frankly kind of startled,' said researcher Nicholas Fisher, who reported the findings on Monday in the Proceedings of the National Academy of Sciences. The levels of contamination were 10 times higher than the amount measured in tuna off the California coast in previous years. But even so, it's still far below safe-to-eat limits set by the U.S. and Japanese governments, so is unlikely to affect humans. Since the March 2011 earthquake and subsequent tsunami that badly damaged the Fukushima Dai-ichi reactors, smaller fish and plankton have been found with elevated levels of radiation in Japanese waters. Prized: Sushi chef Kiyoshi Kimura poses next to a 269 kilogram bluefin tuna, which can fetch $24 for a thin slice at top Tokyo restaurants . But scientists did not expect the nuclear fallout to linger in huge fish such as bluefin tuna, which grow to 10 feet and weigh over 1,000 pounds. This is because they generally shed radioactive substances easily, metabolising it as they sail the world. The tuna captured off the California coast were contaminated with radioactive material from the Fukushima meltdown of March last year. When an earthquake and tsunami struck Japan, they overwhelmed the defences of the Dai-Ichi power plant, leading to the worst nuclear disaster since Chernobyl. Dangerous amounts of radioactive material were carried by wind away from the plant, which is just 30 miles from the Pacific Ocean. When those substances - such as isotopes caesium-134 and caesium-137 - entered the water, they also entered the food chain and living environment of fish such as tuna. The face that the radioactive caesium has stayed in the tuna's system a year later, even after a 6,000-mile swim across the ocean, shows just how much of the isotope was released by the meltdown. While scientists claim that the fish is currently safe to eat, many of the effects of radioactivity on the human body are still unknown. Five months after the Fukushima disaster, Fisher and his team decided to test Pacific bluefin, that spawn off the coast of Japan and swim east to California and Mexico. To their surprise, tissue samples from all 15 tuna captured off the San Diego coast contained levels of two radioactive substances - caesium-134 and caesium-137 - that were higher than in previous catches. The scientists also analysed yellowfin tuna, found in the eastern Pacific, and bluefin that migrated to Southern California before the nuclear crisis, to rule out any other causes for the enhanced radiation, such as ocean currents. They found no trace of caesium-134 and only background levels of caesium-137 left over from nuclear weapons testing in the 1960s. The results 'are unequivocal. Fukushima was the source,' said Ken Buesseler of the Woods Hole Oceanographic Institution. Bluefin tuna absorbed radioactive caesium from swimming in contaminated waters and feeding on contaminated prey such as krill and squid, the scientists said. As the predators made the journey east, they shed some of the radiation through metabolism and as they grew larger. Even so, they weren't able to completely flush out all the radioactivity from their system. 'That's a big ocean. To swim across it and still retain these radionuclides is pretty amazing,' Fisher said. Debris: Radioactive tuna is not the only casualty of the tsunami to wash up in North America, as this motorbike which found its way from Japan to Canada proves . Can I have my ball back, please? Another Japanese visitor to the U.S. is a football owned by Misaki Murakami, left, and found by David Baxter, right, on a beach in Alaska . Pacific bluefin tuna are prized in Japan where a thin slice of the tender red meat prepared as sushi can fetch $24 per piece at top Tokyo restaurants. Japan consumes 80 per cent of the world's Pacific and Atlantic bluefin tuna. But researchers say the real test of how radioactivity affects tuna populations comes this summer when they plan to repeat the study with a larger number of samples. Bluefin tuna that journeyed last year were exposed to radiation for about a month but the upcoming travelers have been swimming in radioactive waters for a longer period. They are also keen to track the movements of other migratory species including sea turtles, sharks and seabirds, now they know bluefin tuna can transport radiation.
increased radiation found in the Pacific bluefin Sciences. The levels of contamination were 10 times higher than the amount measured in tuna off system a year later, even after a 6,000-mile swim scientists claim that the fish is currently safe to eat, many of the effects of radioactivity on from Japan to Canada proves . Can I have my ball