Radiation from the Fukushima nuclear power plant in Japan has not reached the California coastline, according to new results from tests on kelp. Scientists monitoring kelp forests on the West Coast announced the results on Wednesday.

Kelp forests in the ocean are like sponges. They suck up what's in the water around them. So scientists with a project called Kelp Watch 2014 are testing kelp from Baja California up to Alaska for cesium-134, one of the radioactive isotopes from Fukushima.

And so far, says Kai Vetter, a nuclear scientist at the University of California, Berkeley and Lawrence Berkeley National Laboratory, there's no cesium-134. He just got the results back from kelp collected in February and March.

"But the expectation is even if we find cesium or other isotopes that we can associate to Fukushima, the concentration we expect, again, will be extremely small," he said.

In his tests, Vetter did find cesium-137, another radioactive isotope. That, he says, was left behind after atmospheric weapons tests. Scientists expect to eventually see cesium-137 from Fukushima, too, but that Cs-137 wouldn't be here without the Cs-134, Vetter explained.