The Mediterranean region of Bosnia and Herzegovina, which presents the Adriatic (Mediterranean) Sea Basin, is composed of Neretva, Trebisnjica and Cetina River Basins, and of the narrow coastal zone around Neum Municipality. Neretva and Trebisnjica River Basins have an area of 10,100 km2 or 81.4 per cent of the total Adriatic Sea catchment area, w'hile Cetina River Basin in Bosnia and Herzegovina has an area of 2,310 km2 or 18.6 per cent of the total Adriatic Sea catchment area. The Eastern Adriatic Sea, including its Bosnia and Herzegovina part, is a shallow transitive area with a great number of typical pelagic and benthic species adapted to the high salinity.