Since obtaining membership to the Asia–Pacific Economic Cooperation in 1998, Vietnamese fishery product exports, particularly frozen catfish fillets, to the USA have increased significantly, supported by a bilateral trade agreement (BTA) between the two countries signed in December 2001. With similarities in texture and taste, but of lower price, catfish imports from Vietnam were a concern for US catfish producers. To protect its catfish sector, the US Congress passed a labelling law in November 2002 restricting the use of the word ‘catfish’ to only those fish of the Ictaluridae family, which is farmed popularly in southern states of the USA. Antidumping measures, a trade policy permitted by the World Trade Organization, were also issued by the USA in 2003 leading to tariffs ranging from 44.66% to 63.88% levied on frozen fillet catfish imported from Vietnam. This paper uses selected econometric models to examine the effects of the US laws and policy on prices and trade flows, as a part of a comparative case study of primary production. The models show that the antidumping tariff raised the US domestic price of processed catfish and lowered the Vietnamese export price. The fall in the price of Vietnamese catfish caused by the US tariff raised market demand outside the USA and consequently boosted the Vietnamese export volume of catfish. Empirical models with monthly data from January 1999 to December 2005 examined the effects of the BTA, the US antidumping and the labelling laws on the price and trade flow of frozen catfish fillets. Although the BTA benefited US consumers, the antidumping measures were not favourable to them or to US farmers. The labelling law in reality harmed the US catfish industry.