Invasion and potential risks of introduced exotic aquatic species in Indian islands

India is endowed with a wide range of ecosystems, of which oceanic island ecosystems viz. Andaman and Nicobar and Lakshadweep are unique and ecologically fragile because of the high degree of endemism in species composition. Altogether 25 species under different faunal groups such as cnidarians, polychaetes, cirripedes, mollusks, and ascidians are reported as invasive species in Indian islands, of which 24 species are found in Andaman and Nicobar Islands, while 4 species are available in Lakshadweep. Ship-mediated invasions, especially ballast water discharge and ship-hull fouling, are the major source of invasions as these islands are located in the vicinity of the international sea route. In the present paper, we have represented these non-native species of fauna and flora to discriminate and identify them as non-native or invasive. This study deals with the diversity and distribution of aquatic invasive species in islands and their detrimental impact on the island ecosystem.