Since several years, overproduction of sea bass and sea bream in Europe has provoked a severe diminution of retail price of commercial size fish and producers have seen their profit margins decreasing dramatically. In such a depressed and saturated market, optimization of production processes is not anymore sufficient to recover the narrow profit margin of industrialists. Genetic selection should give the opportunity to acquire a sustainable competitiveness, with the possibility to supply the market with "seeds" improved for a simple but economically sensitive criterion: growth rate, which remains one of the main breeding goals of fish farmers. Nevertheless, today, the Mediterranean aquaculture industry is not yet deeply involved in such programs. It seems that not enough critical information regarding efficiency of breeding programs or necessary means to set them up, has reached the sector decision makers. The aim of the project is to fill this gap providing to the participating SMEs, this lacking information: performance comparison (based on measurement of several traits of commercial interest) of the 3 geographic and genetically differentiated wild sea bass populations; assessment and comparison to a control line, of the genetic progress of two first generation selected sea bass populations derived from classical individual selection and optimized individual selection, called PROSPER; a detailed description of the studied selection approaches and their associated costs. At the end of the project, participating SMEs will have the basic information necessary to evaluate the opportunity to implement such programs in their own facilities and adequate fish to start with. COMPETUS will also test the PROSPER selection strategy developed for small to medium-scale breeding programs and that was exclusively used in French aquaculture up now. It will be described to fish farmers of other EU members or associated states ensuring a wide trans-national cooperation.