A tracking system for ships at sea, said system comprising: - terminals mounted on a predetermined number of collecting means, each of said collecting means comprising a terminal including: • means (6, 7) for detecting identification signals emitted by surrounding ships located in a collecting area around the corresponding collecting ship; • means (8, 9) for determining the current position of the corresponding collecting means; and • means (10, 13) for recording identification information comprising the identification signals being detected and the current position of the collecting means upon such detection; - a satellite data transmission system, allowing data to be transmitted between said terminals which are mounted on the collecting ships and at least one monitoring centre; - said monitoring centre comprising at least: • means for generating requests which are transmitted by said data transmission system to said terminals so as to ask them to provide the recorded identification information; • means (18, 20) for receiving identification information provided by said terminals, via said data transmission system, in response to a request; and • means for analyzing the identification information being received; - said system comprising means to remotely activate and inactivate a data transmission from the terminals 2 while holding the collection of identification information thanks to means (10, 13) for recording identification information; said system being characterized in that said collecting means are ships said collecting ships, in that said terminals are arranged on the collecting ship so as to present a good radio electrical visibility on the whole horizon, and in that said means (18, 20) for receiving identification information provided by said terminals, via said data transmission system n receive uniquely information in response to a request, said transmission being inactivated for a collecting ship when the latter is in an area covered by another collecting ship. - terminals mounted on a predetermined number of collecting means, each of said collecting means comprising a terminal including: • means (6, 7) for detecting identification signals emitted by surrounding ships located in a collecting area around the corresponding collecting ship; • means (8, 9) for determining the current position of the corresponding collecting means; and • means (10, 13) for recording identification information comprising the identification signals being detected and the current position of the collecting means upon such detection; • means (6, 7) for detecting identification signals emitted by surrounding ships located in a collecting area around the corresponding collecting ship; • means (8, 9) for determining the current position of the corresponding collecting means; and • means (10, 13) for recording identification information comprising the identification signals being detected and the current position of the collecting means upon such detection; - a satellite data transmission system, allowing data to be transmitted between said terminals which are mounted on the collecting ships and at least one monitoring centre; - said monitoring centre comprising at least: • means for generating requests which are transmitted by said data transmission system to said terminals so as to ask them to provide the recorded identification information; • means (18, 20) for receiving identification information provided by said terminals, via said data transmission system, in response to a request; and • means for analyzing the identification information being received; • means for generating requests which are transmitted by said data transmission system to said terminals so as to ask them to provide the recorded identification information; • means (18, 20) for receiving identification information provided by said terminals, via said data transmission system, in response to a request; and • means for analyzing the identification information being received; - said system comprising means to remotely activate and inactivate a data transmission from the terminals 2 while holding the collection of identification information thanks to means (10, 13) for recording identification information; said system being characterized in that said collecting means are ships said collecting ships, in that said terminals are arranged on the collecting ship so as to present a good radio electrical visibility on the whole horizon, and in that said means (18, 20) for receiving identification information provided by said terminals, via said data transmission system n receive uniquely information in response to a request, said transmission being inactivated for a collecting ship when the latter is in an area covered by another collecting ship.