Radioactive cesium was detected from two minke whales caught off the coast of Kushiro, Hokkaido, in Japan's so-called research whaling, a whalers' association said Tuesday.
While the level of the radioactive material remained below the temporarily set upper limit, the association officials said during a press conference in Kushiro that the contamination must have been caused by the continuing nuclear crisis at the Fukushima Daiichi power plant and that they will closely monitor future developments.
During the research whaling that started in late April, 17 whales were caught, and researchers examined six of them. Of the six, two were found tainted with 31 becquerels and 24.3 becquerels of cesium per kilogram of whale meat, they said.
The upper limit tentatively stands at 500 becquerels per kilogram.