The database includes records of species introduced or transferred from one country to another.

Some example maps demonstrate the extent of introductions. Please click on a chart to enlarge it.

Cyprinus carpio introductions by year	Oreochromis mossambicus - O. niloticus introductions
Number of introductions by country	Species introduced for aquaculture purposes

Database
Click here to search for species in DIAS (online query), the database now contains more than 5 500 records.

Users aware of other introductions of aquatic species not already included in the database or that have additional information on the records in the database are requested to fill in the Input Form. Periodically this information will be validated and added to the database.

The FAO Database on Introductions of Aquatic Species (DIAS) was initiated by R. Welcomme in the early 1980s. Initially it considered primarily only freshwater species and formed the basis for the 1988 FAO Fisheries Technical Paper No. 294. Today DIAS has been expanded to include additional taxa, such as molluscs and crustaceans, and marine species.

In the mid-1990s a questionnaire was sent to national experts to gather additional information on introductions and transfers of aquatic species in their countries.