The south-western coast of Madagascar, fringed with one of the biggest coral ecosystem on Earth, is inhabited by a vezo population whose fishing lifestyle has been adapted to the marine environment for centuries. Since the 1990s, international institutions and development agencies have been improving vezo’s fishing gear and setting up a more efficient organization of these « traditional fisheries », whose products are sold on world markets by corporate networks. According to ecological and social sciences investigations, the South West Madagascar coastal region has known a strong demographic growth, a fast development of the commercial fisheries and an accelerated ecological degradation. These processes trigger the depletion of some valued marine species and disruption in the Vezo communities. Partially grounded on data gathered through two surveys, this paper aims to demonstrate that this systemic crisis is due to the vezo fisheries’globalization. The main results of these surveys show that while fishermen’s daily incomes are low, fishing is intensive and commercial species are declining. Though many fishermen are conscious of the coral reef degradation, most of them do not believe that marine resources could vanish from the coastal region, for « the sea is inexhaustible ». The linking of the « modernized » Vezo fisheries to the world economy, a highly profitable business as shown by the Copefrito case, is part of the geographical opening up of the South West Madagascar coastal region. This process exerts heavy footprints on the marine ecosystem and makes the Vezo lifestyle unsustainable.