Pacific bluefin tuna carrying radioactive cesium from the Fukushima nuclear plant have been found off the coast of California. Fifteen young tuna caught off San Diego last year showed radiation that is not at dangerous levels, but offers a window to scientists studying the migration patterns of marine life. Researchers were surprised to find the cesium in all 15 fish sampled; the radioactive isotope had not been detected in fish caught before 2011, nor in yellowfin tuna native to California waters.
The Los Angeles Times quotes researcher Daniel Madigan, a doctoral candidate at Stanford: “We showed that a bluefin tuna is capable of picking up radioactive material and transporting it across the ocean. That’s new. Traditionally people don’t think of migratory animals as transport vectors for radioactive materials.”
This is not the first time that evidence of the Fukushima power plant meltdown has reached North America. Very low radioactivity was detected in milk in Washington and California last year.
The radiation levels are extremely low and do not pose a health risk to humans — the bluefin tuna have far more to fear from us, since they are being fished to near extinction, with international action slow in coming. However, what it does demonstrate are the far-reaching, systemic consequences of human actions. As we saw with the tsunami debris, there is no “away;” whether materials are swept away or thrown away, they still end up in someone’s back yard. That’s true for plastic bottles, air pollution and, as this has demonstrated, for nuclear waste residue.
Image: Pacific bluefin tuna by aes256 via Creative Commons license