The introduction and rapid expansion of farmed salmon production in the mid 1980s has transformed the international market for salmon. Spain is one of the most important markets for fish within Europe and the world, and has seen a substantial increase in its demand for salmon. As in other European countries, this has raised concerns that the increased supply of salmon to Spain may have detrimental effects on the market prices of traditional (wild‐caught) species. In this paper, the extent to which salmon competes with the main traditional fish species in the Spanish market is examined using market delineation methodologies. In particular, the potential interactions between species is examined in a multivariate cointegration framework. The results suggest that salmon is at best only a weak substitute for tuna, hake and whiting, but no significant interaction could be found.