One environmental event verified during the last years in the Mediterranean sea is that the presence of tropical fishes is causing death of the original fauna. This has attracted the attention of not only the fishermen, but also that of the European Community and all of the associations (public and private) which work to preserve the environment. There are several initiatives to preserve the environment, and the “fermo biologico” is one of these. It tries to solve the Mediterranean fish’s depopulation problem, restricting the fishing in some period of the year. As known, the management of the biological resources is addressed to guarantee the environmental sustainability. This sustainability can be guaranteed by those who work in the fish sector, through new leisure activities, able to answer the increasing touristic demand. The objective of this study has been that to investigate whether leisure activity like fishing tourism can preserve the Mediterranean ecosystem and at the same time guarantee an additional income to the fishermen. This income could possibly balance for the obligation days stop, imposed them by the biological stop measure. The study has been conducted in the summer 2009 and has involved fishermen that practise fishing tourism in the Southern part of Sardinia.