research database, the cumulative position reports gives an analysis of fishing vessel tracks in search of fish. Coupled with species-specific fishing licenses and catch reports, fisheries managers can estimate the amount of a given fish in an area, the amount taken by fishing vessels, and project overfishing before it happens. Safety VMS itself can help in search and rescue (SAR), especially when the SAR organization participates in the Global Maritime Distress Safety System(GMDSS). Some VMS have built-in Emergency Position-Indicating Radio Beacons (EPIRB), or SART capability although a dedicated VMS unit may not be able to have an emergency beacon that automatically floats to the surface and starts transmitting when it detects it is in salt water. At the very least, the SAR agency can get a last reported location of the vessel, and perhaps its course, from the FMC. Enforcement VMS obviously is part of fisheries enforcement, but, along with other systems, it can be part of overall sea surveillance. When a radar or other sensor detects a given vessel, VMS can tell the center that monitors the radar whether the radar target is a known fishing vessel. There may be correlation between AIS/VTS and VMS. Technologies and components Any vessel tracking system, including VMS, requires technology on the vessel, ashore, and communications between them. In addition, there may be additional communications from the Fisheries Management Center (FMC) of the vessel's country of registry, and regional or national FMCs of the waters in which the vessel is fishing. Functions aboard the vessel The most basic function of a VMS is to determine the vessel's location at a given time, and periodically transmit this information, to a monitoring station ashore. Different VMS systems use different communication technologies, including AIS, Inmarsat, Iridium and Argos depending on the functionality required by the particular VMS system. VMS components on the vessel sometimes are called VMS, or sometimes Automatic Location Communicators (ALC). These minimally include a GPS antenna and receiver, a computer (which may be embedded or user-supplied), and a transmitter and antenna appropriate for the communications that links the vessel to the flag center. In practice, many of the VMS components also have applicability, along with non-VMS marine electronics, to a wide range of functions aboard a fishing vessel. These include navigation, finding fish, collision avoidance, routine voice and email communications, etc. Selecting a VMS system is most dependent on what vendors and models