Cultured shrimp production has been growing dramatically on the world market over the last 15 years and some of the farm-raised species are now considered as price-indicators on the main market places. One may, therefore, expect the price of theses cultured shrimp to have an impact on the price formation of other species and especially on wild shrimp with which they compete. In this paper, the authors address this question in the case of the wild shrimp Penaeus subtilis exploited by the French Guyana fishery (South America) and competing on the French market with the cultured Thai shrimp 'Back Tiger'. A series of econometric tests issued from the co-integration theory is performed between the price series of the two products. These tests indicate that the two series are co-integrated and that the black tiger market acts as a market leader for the French Guyana shrimp product. The authors then discuss the reasons of the current predominance of farm-raised shrimp on wild-caught product (and in particular the French Guyana shrimp) and identify the constraints that the French market demand induces on both producers and importers. In the light of this analysis, a commercial strategy that would mitigate the impact of the Thai shrimp on the French Guyana product is suggested. © 2000 Elsevier Science B. V. All rights reserved.