Figure 1. Example outputs of SeaCras’ vessel monitoring analytics in the Badija area. Left: Vessel detection and classification, showing anchored vessels, vessels moored to coastal infrastructure, and vessels in migration, with an inset of vessel-level attributes. Right: Detection of vessels moored along coastal infrastructure, with mooring length, total detected vessels, and estimated capacity occupancy.
Nautical tourism and leisure boating have always been a thing of luxury and prestige. You set out from the port or the marina, and there are no limits… Or are there? In fact, there are several things that skippers and boat owners need to respect, everywhere on the planet:
- Availability of anchoring or boat mooring spots, especially on remote islands
- Environmental protection (MARPOL)
- Navigation and Collision Avoidance (COLREGs)
While navigation and collision avoidance rules are something that skippers and boat owners generally abide by, the availability of anchoring or boat mooring spots, lack of established marine analytics, and environmental protection in general are sadly neglected.
1) Availability of Anchoring or Boat Mooring Spots, Especially on Remote Islands
- Benthic Protection: Rules often prohibit anchoring in areas with sensitive seagrass (like Posidonia oceanica in the Mediterranean). Dropping a heavy anchor and chain can “scour” the seabed, destroying carbon-sequestering habitats.
- Designated Mooring Zones: To prevent ecological damage, many coastal countries now require vessels to use “eco-friendly” permanent mooring buoys instead of dropping their own anchors.
- The skipper is legally responsible for ensuring the anchor holds. If your anchor “drags” and you hit another boat, you are generally liable for the damages because you failed to maintain a proper anchor watch or failed to use sufficient scope (the ratio of chain length to water depth).
The WWF study on the Mediterranean published data suggesting that 179,000 vessels may have anchored on seagrass in 2024, 45% of them larger than 24 meters. The study which was based only on Automatic Identification System (AIS) data suggested a huge impact on protected environmental areas covered with seagrass Posidonia oceanica.
Measuring Environmental Impact
On the other hand, company SeaCras as a contractor to environmental agencies in 2023 identified over 150,000 vessels performing illegal anchoring over Posidonia oceanica meadows only on a small part of the Adriatic sea coastline. In 2025, the number increased by approximately 12%. Locations in Šibenik-Knin county, Split Dalmatia County, and Natura 2000 sites in Dubrovnik-Neretva County were subject to the study. Vessel fleet detected showed that the majority of vessel sizes were under 16m, which makes them invisible to AIS.
The scaling factor suggests that there are over 400 000 annual illegal vessel activities of anchoring over protected areas or using pristine nature instead of dedicated and specialised infrastructure only in Croatia’s coastline. The danger to benthic species and habitats is real and mechanical destruction by anchors is alarming. SeaCras’ calculation on the Mediterranean surpasses 1 million illegal anchoring of vessels of all sizes, annually. That’s right, 1 million.
Moreover, this means that governmental agencies are completely blind to more than 90% of maritime traffic, with nautical tourism forming a significant part of it.
This raises additional questions, such as: to what extent marine pollution occurs, based on MARPOL pollution definitions.
2) Environmental Protection (MARPOL)
International Convention for the Prevention of Pollution from Ships (MARPOL) is an international treaty adopted by the International Maritime Organisation to prevent and minimise pollution of the marine environment from ships due to operational or accidental causes.
- Oil Pollution (Annex I): Discharge of oil or oily mixtures into the sea is strictly prohibited. Even small bilge leaks can lead to heavy fines.
- Garbage (Annex V): It is illegal to discharge any plastics into the sea. Food waste can only be discharged under specific conditions (usually more than 12 nautical miles from land).
- Sewage (Annex IV): In many territorial waters (and specifically in “No Discharge Zones”), holding tanks must be used and emptied only at designated pump-out stations or beyond the 12-mile limit. Blackwater tanks are big problems for pollution hazards with intestinal enterococci and E. Coli diseases when released in smaller and shallower bays in vicinity of swimmers.
- Another, less pronounced negative effect is invasive species expansion.
3) Navigation and Safety (COLREGs)
Convention on the International Regulations for Preventing Collisions at Sea (COLREG) is an international treaty that sets out the rules of the road for ships at sea—establishing navigation, right-of-way, lighting, signalling, and conduct requirements to prevent collisions between vessels.
Under the international Rules of the Road, an anchored vessel has specific obligations because it is considered “restricted in its ability to maneuver” compared to a vessel under way:
- Obstruction of Fairways: It is strictly prohibited to anchor in narrow channels or fairways where you might obstruct the passage of other vessels.
- Day Shapes and Lights: You must display a black ball (day shape) or a single all-around white light at night to signal to other mariners that you are not moving.
- Aground vs. Anchored: There are distinct rules for a boat that is intentionally anchored versus one that has run aground; the latter requires additional signaling (two red lights at night).
But can nautical tourism actually be sustainable? And how can data help us achieve that?
So What Can We Do to Continue Enjoying Nautical Tourism, but Minimise Our Adverse Effects?
Maritime operations — including nautical tourism, leisure activities, passenger vessels, and fishing boats — generate significant greenhouse gas emissions. Advanced marine analytics allow precise measurement of these emissions by region, specific locations, and across seasonal, annual, and multi-year periods.
These tools also enable accurate evaluation of newly regulated pollutants, such as underwater noise, which impacts fish and marine mammals such as dolphins and whales in different ways. Changes in animal behaviour caused by noise can threaten fragile marine ecosystems.
These effects are particularly evident in narrow channels and bays along the Adriatic coastline, as well as in the pristine crystalline seas of Greece, Indonesia, Thailand, and other sensitive marine environments.
Marine analytics is not only used to monitor environmental impacts but also to improve maritime safety. It provides actionable insights for people at sea, including boat owners, skippers, and captains, enhancing navigation, risk awareness, and overall operational efficiency.
Predictive analytics can forecast areas of dense maritime traffic, helping reduce the risk of collisions and ensuring safer journeys. This also improves nautical tourism passenger satisfaction, reduces costs for early responders and coast guards, and contributes to more effective management of maritime destinations.
Now is the time to turn insight into action — embrace marine analytics to safeguard our oceans, elevate maritime safety, and shape a smarter, cleaner future at sea.