Vessel Monitoring Systems (VMS) is a general term to describe systems that are used in commercial fishing to allow environmental and fisheries regulatory organizations to track and monitor the activities of fishing vessels. They are a key part of monitoring control and surveillance (MCS) programs at national and international levels. VMS may be used to monitor vessels in the territorial waters of a country or a subdivision of a country, or in the Exclusive Economic Zones (EEZ) that extend 200 nautical miles (370.4 km) from the coasts of many countries. VMS systems are used to improve the management and sustainability of the marine environment, through ensuring proper fishing practices and the prevention of illegal fishing, and thus protect and enhance the livelihoods of fishermen. The exact functionality of a VMS system and the associated equipment varies with the requirements of the nation of the vessel's registry, and the regional or national water in which the vessel is operating. Within regional and national VMS initiatives there are also sub-divisions which apply different functionality to different vessel categories. Categories may be size or type of vessel or activity. For example: Local/regional fish such as scallops in the Northeast U.S., anchovies in Peruvian waters, or rock shrimp in the Gulf of Mexico Highly migratory species (HMS) such as tuna and billfish, or Patagonian toothfish (Dissostichus eleginoides) in the Antarctic. which can be caught in multiple regions In this discussion, VMS relates specifically to fisheries management systems. VMS describes the specific application of monitoring commercial fishing boats. It is not to be confused with VTS which is describes the specific application of monitoring marine traffic primarily for safety and efficiency in ports and busy waterways. It is also not to be confused with specific communication technologies such as AIS, Iridium, Inmarsat, Argos, GPRS which relate to the communication method on which data is transmitted. Different VMS systems will use different communication technologies depending on the functionality requirements imposed by a national or regional VMS initiative. The cost of VMS components will vary according to the functionality requirements of the specific system being implemented. In general the higher the functionality the more expensive the equipment and required data link (airtime costs). The cost of a VMS system therefore varies and thus the level of government subsidy (if any) varies according to national and regional requirements. EU and US VMS systems require expensive onboard equipment and