A piece of bluefin tuna (Maguro) sits on a sushi plate at Yum Yum Fish in San Francisco.
Stanford researchers believe they have found the first instance of radioactive materials from Japan's nuclear disaster being transported by migrating animals through the sea off the coast of California.
Researchers from the farm, working with scientists from Stony Brook University, say they found the radiation in bluefin tuna in waters near San Diego.
But before sushi fans change their eating habits, the researchers were quick to point out that the radiation levels were not believed to be high enough to threaten human health.
Nicholas Fisher, a professor at Stony Brook and a co-author of the study, said while her team was surprised by the results there is no reason for panic.
"All living things are radioactive," he said. "Primarily attributable to the naturally occurring potassium-40. The potassium-40 radioactivity in the bluefin tuna was over 30 times higher than that from the radioactive cesium. So, the radioactivity from the spill really only adds 3 percent more radioactivity than the background level."
In March 2011, a tsunami caused flooding at the Fukushima Dai-ichi nuclear power plant in Japan, which led to a failure of the plant's cooling system.
The overheated plant spilled radioactive water into the sea. Scientists have been monitoring the ocean since, waiting to see if that material would make its way to California.
Japan in particular has been monitoring the sea life off of its coast for radioactive material but few were watching the animals as they migrated away from the country's water.