SACROIS is a data crossing algorithm that produces professional fishing activity data series (validated, consolidated and qualified production and effort data) for the vessels registered in the Community Fishing Fleet (CFP) file. SACROIS selects the best of the available information sources to produce the reference fishing activity data. SACROIS consists of an operational application for reconciliation, verification and consistency checks of different unitary data streams. The SACROIS algorithm does not correct the data, its objective is to : - provide the best possible estimate of the various elements making up a tide from the available data sources - to identify the incompleteness of the various data sources and to propose a synthesis completed by indicators of data qualification resulting from the crossings. Twice a month, the SACROIS algorithm produces a new data source, a synthesis of all the available data sources: the reconstructed SACROIS tides. The SACROIS data have been calculated since 2000 for all fleets for which data are available: - North Sea - Channel - Atlantic (excluding tropical seiners), - Mediterranean (excluding bluefin seiners), - DOM (Reunion, Mayotte, French Guiana and the West Indies).