Exotic herbivorous fish in Mediterranean ecosystems: biological causes and ecological consequences of an ongoing invasion

Leader S.Villéger


Mediterranean coastal ecosystems are facing unprecedented anthropogenic disturbances that synergistically threaten their unique biodiversity and the ecosystem services they provide to human populations. The ongoing expansion of herbivorous fishes from the genus Siganus, which entered the Mediterranean Sea from the Red Sea after Suez Canal opening, is one of the most critical issues. Siganus populations tend to exclude the single native herbivorous species (Sarpa salpa) and to cause a widespread depletion of macrophytes. Although some aspects of Siganus ecology have received attention, there are still knowledge gaps about the causes and consequences of this invasion. EXOFISHMED project will thus address two questions (1) which factors explain how exotic fishes are supplanting the native species ? (2) what are the consequences of this species replacement on the functioning of ecosystems ? To answer these questions we will conduct a multidisciplinary approach to compare the biological attributes and ecological roles of native and exotic herbivorous fish species.