Elysia subornata (Mollusca) a potential control agent of the alga Caulerpataxifolia (Chlorophyta) in the Mediterranean Sea

The biological characteristics of Elysia subornata (Mollusca: Opisthobranch ia) were studied in an aquarium to assess its risks and chance of success a s a potential biological control agent against the invasive alga Caulerpa t axifolia (Chlorophyta) in the Mediterranean Sea. This species feeds Only on Caulerpa and has benthic larval development. Dietary switching is possible on some Mediterranean Caulerpales but feeding on other algae and sea grass is unlikely. The main limiting factor for the success of studied Caribbean strain of E. subornata are the Mediterranean winter temperatures which are lethal for that species. For the five months of the year which are favoura ble for feeding, growth and reproduction, the tested strain of E. subornata cannot reach a population density capable of controlling C. taxifolia.