Hayama Nakamura, 67, former chairman of Tokyo-based firm Hamashin, was also ordered to pay 1 million yen in fine.

According to the sentence, Hayama and his accomplice labeled about 5,400 packages of grilled eel products made from eels farmed China as those raised in Kagoshima Prefecture in May 2008 and sold them to a wholesaler in Tokyo for about 2.9 million yen.

Judge Toshiaki Fujii ruled that Nakamura was the main culprit in the false labeling practice and said, "(The defendant) violated the principle of fair competition in the market and pursued profits without considering the safety of the food products for consumers."

Fujii also said the false labeling was a "crime against social morals which immensely damaged the trust of citizens" regarding the origin of the food.

The court also sentenced Isamu Fukushima, a 66-year-old former executive of the company, to 18 months in prison, suspended for two years, for assisting Nakamura in the false labeling.

Food wholesaler Yayoi, which Nakamura had practically managed, was also ordered to pay 3 million yen in fine.

In a similar case, a seafood company president in Tokushima Prefecture and others were arrested last November on suspicion of disguising grilled eels farmed in China as those raised in Aichi Prefecture and selling them through a Kobe-based wholesaler.