These days it is not uncommon for frozen fish products to travel tens of thousands of kilometers.

Frozen food producer Findus Finland says it ships some of its fish caught in the northeastern Atlantic on to processing plants in Thailand. Ready-packaged products are then sent back to Finland, landing in supermarkets' frozen food bins.

China's vast army of low-cost labour has armed it with a competitive seafood processing industry. And it is these low labour costs that Findus says make it possible for its fish to be filleted.

Lea Pessi of Finland's Food Safety Authority Evira says Finland has seen a surge in fish imported from China this year.

The food safety watchdog monitors all incoming fish. But right now fish from Japan is drawing the most scrutiny owing to radiation fears following this spring's earthquake that damaged the country's nuclear reactors.

But there is no reason to say no to sushi, according to Evira.

“The tested fish has been normal,” says Pessi of Japanese fish sold in Finland.