The biological and ecological characteristics of the South Adriatic Sea impact specific quality of the ecosystems in the entire Adriatic because coastal areas of the South Adriatic are entirely surrounded by the deep oligotrophic water that flows from the Ionian Sea along eastern Adriatic coast. Former data did not adequately encompass interactions between biocenoses in the south and their resultant influence on the other parts of the Adriatic Sea. Continual interactions between biocenoses of the offshore and inshore ecosystems are probably a key requirement for stable dynamic ecological stability in the sea. Vertical migrations in the offshore deep waters and horizontal transport of matter and energy contribute to that equilibrium. The basic goal of the project is to investigate and demonstrate that the interactive relations in biocenoses of this, most voluminous, part of the Adriatic significantly support stability of ecosystems in the other parts of Adriatic Sea. This project should contribute to new findings by: 1)defining vertical migrations in the deepest part of the Adriatic Sea, matter and energy transport between sea layers and different trophic groups of holoplankton and meroplankton; 2)collecting evidences of typical south Adriatic species in plankton, benthos and nekton, determining specific quality of the observed ecosystems, their relationship and influence on the dynamic stability of the Adriatic; 3)documenting the high quality of the south Adriatic ecosystems and spatial-temporal interactions of the biocenoses between the South and North Adriatic; 4) determining typical biocenoses, appearance of the scarce and new species, their distribution in the South Adriatic and migrations northwards; 5) determining and describing various aspects of specific populations in the coastal and open sea systems of the South Adriatic and comparing them with other regions.