The firms have taken their appeal to the US Court of International Trade, claiming that the new duties, of up to 113 per cent, will destroy their business with the large US market.
The US began its investigation into trade in warm-water shrimps from China in early 2004, setting the price of Indian shrimps as its baseline and deciding that the Chinese companies were 'dumping' large quantities of their shrimps onto the market at a knockdown price.
But, the Chinese claim, the US officials were in fact comparing prices between two completely different species of shrimp. As a result, their assessment of the respective values of the two products was therefore incorrect - and indeed in violation of World Trade Organisation rules.
They also claimed that the US officials had ignored their suggestions that the basis for the calculation was incorrect.
This is not the first time Chinese producers have come up against accusations of dumping from the US - in April 2000, the US claimed that Chinese apple juice producers were dumping large quantities of concentrate onto the market, a claim denied by the Chinese on the same grounds that the US authorities had calculated erroneously. The Chinese won their appeal that time, and are clearly confident of a similar outcome this time.
Vietnam, whose shrimp exports were also found to be sold in the US at less than fair prices, has added its voice to the Chinese complaints.
The US Department of Commerce began its investigation at the request of the US industry association, the Southern Shrimp Alliance, which claimed that imports of shrimp from China and a number of other countries had increased by 71 per cent between 200 and 2003 at the same time as prices had dropped by 42 per cent.