The study's authors are not warning of a public health risk, however.

"I wouldn't tell anyone what's safe to eat or what's not safe to eat," lead author Daniel Madigan, a marine biologist at Stanford University, told Reuters. "It's become clear that some people feel that any amount of radioactivity, in their minds, is bad and they'd like to avoid it. But compared to what's there naturally... and what's established as safety limits, it's not a large amount at all."

In fact, according to New Scientist, the radiation may even allow biologists to learn more about the migration patterns of other sea animals such as turtles and sharks, by using the levels of isotopes in their systems to calculate when they passed through Japanese waters.

The research team expects the radiation to decline gradually, co-author Nicholas Fisher of Stony Brook University told Bloomberg. They plan to conduct a follow-up study later this year.