Aquatic invasive species (AIS) and bio-invasions are global environmental issues inmarine, brackish and freshwater ecosystems of the world. Similar to trends observedin other countries, the number of aquatic invasive species in Iran
has increasedconsiderably over recent decades causing harmful algal blooms in the Persian Gulfin the south, Mnemiopsis blooms in the Caspian Sea in the north and changing thespecies diversity and faunistic structure in inland waters. In the case of freshwaterfishes, the number has reached about 24 confirmed species in 8 families which isabout 11% of the freshwater ichthyofauna of Iran. Cyprinidae with 10 species (41.7%of non-native species) is ranked first, followed by Salmonidae (5 species, 20.8%),Poeciliidae and Mugilidae with 3 and 2 species (12.5% and 8.3% respectively), and4 families each with only one species or 4.2%. Aquaculture, sport fishing, control ofmalaria, ornamental purposes, research activities, demonstration in national fairs andaccidental introduction has been the main reasons for these introductions. Aquaticinvasive species have multiple synergistic impacts on the ecosystem through diverseways of hybridization and gene pollution, food competition, transmission ofpathogens and parasites, community level changes, facilitating the introduction ofother taxa and elimination and subsequent extinction of endemic species.Understanding the risks that AIS pose, comparative studies on the ecology and lifehistory strategies of invasive and closely related indigenous species with similarecological life traits, monitoring the rate of invasion, the causal relation betweenpopulation dynamics and species invasion and public awareness, could be effectivemanagement strategies to minimize the bio-invasion impacts. The priority3T may begiven to those invasive species that have already been established in the wild and onpreventing new infestations.