Market prices of the aquacultural farm products are one of the main parameters which influence the economic aspects of a marine fish farm project. In order to propose a simulation of the economic projects' evolution in the technico-economical studies, KURIOS, based the data collected by the marketing service of the big 'Rungis Market' in Paris, and has studied the evolution price, day by day from 1993 to 1995, of several farms and wild fish. The study of this data has enabled the evolution of prices to be followed for one year as well as the general evolution during this period. A comparison in price has been made between the average weights of sea-bass. In fact differences in weight were identified on the data through the origin of the fish (farm sea-bass 400 g, sea bass from trawler 1-2 kilos, line-bass 2-3 kilos). This knowledge of the market may enable the producer to plan his production according to a marketing strategy.