The Fishery and Oceanographic Monitoring System (FOMS) or Sistema de Monitoreo Pesquero y Oceanográfico (SiMPO) in Spanish, was recently established in San Matías Gulf (Argentina) with the objective of monitoring fishing fleet operations. FOMS was also conceived as a fundamental tool for supporting research activities in the context of the Ecosystem Approach to Fisheries. A detailed description of the system is offered. An on line satellite transceiver (Inmarsat D+) supplies data about position, bearing and speed of the vessels, and alarms are automatically triggered whenever vessels are detected fishing in forbidden areas. The off line module integrating one on board CPU with other components: an electronic logbook allowing to the skipper load data on species catches and effort per haul. An electronic scale integrated to the net bag winch, records gross catch weights and allow calculate by catch and discards. A digital camera records images for control mesh sizes when it is hauled on board, and probes gather data of water temperature and salinity. Sensors in the hold record fish storage temperature in order to certifying quality and traceability chain. All information is stored in a Control Center where ad hoc tools are available for a complete data analysis