Nearly two years after a powerful earthquake triggered a leak at Japan's Fukushima Dai-ichi nuclear plant, the effects of that disaster are still being felt on the other side of the planet.
A report released earlier this month by researchers at Stanford University's Hopkins Marine Station found that bluefin tuna caught just off the California coast tested positive for radiation stemming from the incident.
The study looked at the levels of radiocesium, one of the most common results of nuclear fission reactions, in Pacific Bluefun Tuna--largely as way to track the species' migratory patterns as the fish make their cross-oceanic journey in search of prey.
While the report notes that the levels present in the fish are well below what public health officials would deem dangerous, the presence of radiocesium from the damaged reactor shows just how far-reaching the disaster's effects have been.
Daniel Madigan, one of the study's authors, explained that this study shouldn't give people pause about eating tuna caught in the Pacific. "We're exposed to radiation in almost all of the food we eat," he explained.
"Cesium itself isn't safe, but the size dose that someone would get from eating this tuna would be," Madigan added, noting that that the isotope has been present in Pacific marine life for decades as a result of mid-20th century nuclear testing.
Some 40 percent of bottom-feeding fish caught near the Fukushima plant tested positive for high levels of Cesium contamination, indicating that the plant still may be experiencing low-level leaks; however, most of those types of fish stick relatively near the Japanese coast and don't migrate all the way to the Americas.
While the Stanford study noted a drop in cesium levels in tuna caught off of the California coast, data collected by Japan's Ministry of Agriculture, Fisheries and Forestry indicate that a similar drop hasn't occurred in fish caught close to the plant.
The Japanese government has banned both the domestic sale and international export of most fish caught close to the Fukushima coast.
This study is a follow-up to similar one conducted by Hopkins in 2011. The authors wanted to look at whether the radiocesium levels found in the tuna would increase or decrease for their previous examination. Comparing their results to data collected in 2011, the authors discovered that the most recent levels saw a very significant drop in Bluefin caught near California.
Interestingly, this radioactive contamination may ultimately prove to be a boon to the species. A study published earlier this year found that overfishing of the species, which is popular ingredient at Japanese sushi restaurants, has resulted in a 96 percent population reduction from previous levels.
"Bluefin is seriously overfished," Madigan explained. "So having tools to track their migration is important in protecting them."
Additionally, as Forbes notes, the perception that bluefin tuna are contaminated with radiation may lead more restaurants shying away from serving the fish, which would likely go a long way tamping down on the overfishing of a species that can often fetch a pretty penny.
In January, a nearly 500 pound bluefin tuna sold for a record $1.76 million in an auction at Tokyo's famous Tsukiji Fish Market.
For photos from before and after the Japan tsunami of March 2011, click through this slideshow:
