Scope for Growth of the intertidal Lessepsian bivalve Brachidontes pharaonis (Fischer 1870) at varying environmental variables

Abstract

The concept of energy available to organismal growth (i.e. scope for growth; SFG) assumes a central role in studying the behaviour of successful invaders in aquatic habitats: the higher the energy allocated to growth and reproduction, the greater the likelihood of stability/persistence in space over time of aquatic populations. When successful invaders find useful life conditions (i.e., allowing to reach maximum SFG), they compete for space and resources with indigenous species, altering the functioning of entire ecosystems. The Indo-Pacific bivalve Brachidontes pharaonis offers an excellent model for the study of “Lessepsian migration” and the successive colonization at new Mediterranean locations. Here I present data on SFG at varying salinity (from 15 to 45), temperature (from 5°C to 32°C) and chlorophyll-a (from 0.2 to 4 µg l-1). Experimental data showed the ability of B. pharaonis to spread from brackish to hyperaline waters, from cold to warm and from ultra-oligotrophic to hyper-trophic habitats pointing out that the arrival at suitable hard sites in the whole Mediterranean will be only a temporal issue.