Extensive formal and informal trade in fish and fish products takes place at both local and national level. National laws and regulations oversee formal trade within a country. It is, however, the international trade in fish and fish products that is currently an issue of great debate.

States, in order to gain advantage over the trading position of other states, over centuries have raised various tariff and non-tariff barriers to trade. In so doing, they raise the cost to other states of trading within their markets. Trading partners attempt to redress the balance by similarly imposing trade barriers. Ultimately the competitive process of raising trade barriers simply raises costs to consumers and in general leaves no state at particular advantage over others. Recognition that trade could be enhanced by agreeing to a set of rules led to the General Agreement on Tariffs and Trade (GATT) in 1947, and ultimately to the establishment of the World Trade Organization (WTO) in 1995. The current set of trade rules are the Agreements reached at the 1986-94 Uruguay Round negotiations which included a major revision of the original GATT. A number of these Agreements are relevant to international trade in fish and fish products.

The Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) regulates trade in threatened wildlife. Although few aquatic species are included in its lists of threatened species, there has been discussion about an increasing role for CITES in relation to resources exploited by fisheries in marine and large freshwater bodies. The appropriateness of CITES listing criteria for these species has been questioned and is currently being reviewed the FAO in consultation with CITES.