It’s not that many years since a fishing vessel could steam out of the harbour, and until its skipper decided to bring it back home, it could stay pretty much out of touch until it came back through the gaps a few days or weeks later.

It’s something that older fishermen may remember – fondly or not, for a variety of reasons – but those days are now long gone and every fishing vessel over 12 metres in length is required to be fitted with a Vessel Monitoring System, known as VMS.

VMS has been a requirement for any EU fishing vessel over 12 metres since 2012, along with electronic catch reporting, and a similar system is expected to be rolled out for smaller fishing vessels in the near future so that all commercial vessels will be monitored.

For the fishing vessels over 12 metres, a system of electronics linked to the boat’s positioning system transmits data to a satellite, which then sends it to a national or international body that monitors a fishing vessel’s position, course, speed and other parameters.

This system isn’t unique to the UK, or even to Europe, as there are numerous Vessel Monitoring Schemes in operation around the world. For some fisheries one of the conditions for access is to have a VSM installed to report a fishing vessel’s position, and these extend all the way to distant water fisheries such as for krill in the Southern Ocean and to tuna fisheries across tropical regions.

A VMS should not be confused with the Automatic Identification System (AIS) which is also a requirement for many commercial vessels. AIS transmits a ship’s identifier, course and speed to those around it, allowing others to see what other ships are operating in the same waters and what tasks they are undertaking, so AIS is first and foremost a safety measure designed to assist in collision avoidance, and not a monitoring or enforcement tool.

The depth of information available via VMS to a national agency or an international body such as a Regional Fisheries Management Organisation (RFMO) is much more detailed than the fairly minimal data offered by AIS, and VMS is also confidential information. While there are fewer secrets these days now that one fishing vessel can more easily see where others are operating, there is still commercially sensitive data there and one of the prerequisites of being part of a VMS is that the information isn’t shared with competitors as it stays with the agency or management body.

For fisheries management, VMS provides a wealth of hard data on fishing effort that previously would have been compiled from paper logbooks, with information laboriously transcribed, and not always as accurate as accurate as it could have been. Today some of the tricks that could be played in the past – catching fish in one area and logging it in another – are no longer possible as the combination of VMS and electronic catch logging have left very few places to hide.

Unlike AIS, which can be switched off, a VMS isn’t something that can be tampered with. If a fishing vessel disappears from the VMS, it isn’t going to be long before it’s noticed and efforts are made to locate it; first to ensure that it’s safe and secondly to find out what the problem is. There are even penalties for fishing without an operational VMS, and there’s no denying that it’s frustrating to have to leave some good fishing to steam back to port to get a fault in the VMS fixed.

While many fishermen look back fondly to the freedom of a few decades ago when there was nobody watching other than the occasional fisheries patrol or a spotter aircraft, VMS is just one part of the range of advantages offered by today’s electronics and satellite communications systems.

The flip-side of being monitored is that safety at sea is massively increased by the opportunities to call for help in an emergency that satellite systems have made possible, all the way down to the crew being able to check Facebook and WhatsApp when they are off deck.

The reality is that the eye in the sky is here to stay, and that doesn’t have to be a bad thing.