The basic function of VMS is to provide reports of the location of a vessel at regular intervals. VMS tracks the vessel movements and may provide information on its speed and course. The monitoring authorities can check a range of factors including whether the vessel operates in an area where fishing activities are not allowed; operates in the Exclusive Economic Zone of another Member States or third countries or waters under responsibility of a Regional Fisheries Management Organisation; holds the necessary licences and quotas to fish in the relevant area. MS does not replace existing monitoring methods but it makes them more effective by providing the authorities with the location of vessels suspected of having committed infringements thus enabling inspectors on patrol vessels to carry out checks at sea. In addition, if suspected infringements are not immediately detected, irregularities can still be spotted later by cross-checking data.