Abstract : Straits of Bonifacio (south of Corsica) are known for their strong hydrodynamic and the presence of an elaborate and complex marine ecosystem, managed by an international reserve. To have a good knowledge of the water where lives this biomass, the in-situ measurements (currentologic and hydrologic) have been made during 7 oceanographic cruises (CYRCE). Thanks to the current recordings, made by two ADCP (current profiler), one moored, and the other boarded on N/o Tethys II (INSU-CNRS), the current conditions managing the environment are described, on the whole, and by the study of different cases connected with two prevailing winds (NE and SW). The statistic processing of data and their integration by a numeric meshing of the area has allowed a first approach of the current system main phenomenon. The temperature, salinity, dissolved oxygen, turbidity and fluorescence data have showed the characteristic structures and their variability in space and time. Finally the 3D simulation model Symphonie (laboratoire POC-CNRS-Toulouse) is adapted to strait of Bonifacio on nearly one year. This model, has first broaden our currentologic view on the parts not covered by the in-situ measurements, and second has allowed to compare the in-situ and simulated data. Moreover, the implemented tools of the model, have allowed simulations of larvae dispersion from fishing box and simulations of the material dilution. These simulations were done by virtual tracer releases, whose evolution is followed during several days, under different configurations.