While the 2011 Japan earthquake may have wrought devastation to the country’s northern coats, its after effects are still very much present even a year later and though the loss to life and property maybe the earthquake’s more apparent effects, it seems that it is now having possible global ramifications.
Of course when the earthquake and resulting tsunami did strike, it damaged the Fukushima Daiichi nuclear power plant, leading to partial meltdowns of the nuclear reactors, emitting radioactive pollutants. Of course while widespread fallout did not occur, there is evidence that radioactive pollutants have entered into marine ecology, and that this has been picked up in bluefin tuna that had been caught off the coast of San Diego only a couple of months after the earthquake.
The 15 tuna caught showed evidence of radioactivity, their muscle tissue containing ‘elevated levels’ of radioactive caesium. And while the element’s isotope, caesium 137 is already present in seawater, the presence of caesium 134 directly points to the fallout from Fukushima. The ceasium levels found in the bluefin tuna were 10 times more than normal. but the researchers have stressed that the tuna is perfectly edible, though it does point towards a wider interconnectedness in the earth’s ecology.
The research conducted by Stony Brook University and published in the journal, Proceedings of the National Academy of Sciences details how pollution can be easily spread by migrating animals, and speaking about this to the BBC, Prof. Nicholas Fisher said, "It's a lesson to us in how interconnected eco-regions can be, even when they may be separated by thousands of miles," but did add that he “stunned” to find the radioactivity in the fish.
Of course with bluefin tune being such a popular species of the fish, public fears as to the health risks are justified but Prof Fisher said there was nothing to worry about, saying that the caesium levels were within ‘permitted limits’ and lower than other naturally occurring isotopes such as potassium 40.
"The potassium was about 30 times higher than the combined radio-caesium levels. If you calculate how much additional radioactivity there is in the Pacific Bluefin tuna caught in California relative to the natural background - it's about 3%,"
Of course while the researchers maintain that the tuna is safe to eat, they insist that a second study will have to be done to study those tuna that had spent longer in Japanese waters and also add that the study be widen to include other migratory species. Prof Fisher concludes, "This information might be useful in conservation efforts or in managing fisheries."