Sailing the Adriatic and you’ve found the perfect bay to anchor. Have you ever wondered what impact free anchoring might have on the seabed? While we enjoy the beauty of the Adriatic, the seabed suffers immense pressure from free anchoring, threatening biodiversity and the health of the entire marine ecosystem. At first glance, anchoring might seem harmless, but the consequences can be catastrophic and long-lasting.
Management plans for marine protected areas in Croatia often highlight nautical tourism, specifically free anchoring, as one of the most prominent threats to these areas. It’s no surprise, given that Croatia’s charter fleet is among the largest in the world. But the number of vessels in the Adriatic during the tourist season far exceeds the capacity of available moorings. As a result, many boats anchor by freely dropping their anchors onto the seabed.
– The construction of new berths leads to further devastation of natural coastlines, and free anchoring causes the destruction of marine habitats. A necessary precondition for greater sustainability is a strategic approach to the development of nautical tourism, including limiting the number of vessels, improving service quality, and stronger investments in ecological infrastructure and nature protection, – emphasized Matea Špika, Expert Associate at Nature Conservation Department at Sunce.
Pressure on the seabed
Free anchoring often results in physical damage to the seabed and coastal ecosystems, and it especially endangers sensitive seagrass meadows. This pressure has serious consequences, including habitat loss, reduced biodiversity, and the overall degradation of the marine ecosystem. In many cases, the damage is irreversible, and restoring some habitats can take a long time. Posidonia seagrass meadows, for example, grow only one centimeter per year, soft corals like gorgonians grow about two centimeters, and hard corals even more slowly.
Posidonia meadows play a crucial role in preserving biodiversity, providing habitat and food sources for many marine organisms. By sequestering large amounts of CO2, they play a vital role in combating climate change.
Anchor and its chains irreversibly destroy and fragment these meadows, directly threatening their function with long-term consequences for marine conservation.
– Posidonia meadows build a dense network of roots, rhizomes, that form layers up to several meters thick, above and within the seabed (usually sedimentary), called matte. These layers bind exceptionally large amounts of CO2, so anchoring in areas where Posidonia has died off still has a very negative environmental impact, – explains Vida Zrnčić, Expert Associate at Nature Conservation Department.
Anchoring is mostly free and unregulated in the Adriatic
Damage to meadows caused by free anchoring is much greater in areas with more intense use (near settlements and anchorages). The impact also depends on the size of the boats and anchors; larger types have a significantly greater negative effect. Anchoring damage isn’t limited to Posidonia meadows but also affects coralligenous habitats, infralittoral algae, and other sensitive habitat types.
Anchoring in most of the Adriatic is free and unregulated, and often the locations suitable for anchoring (in terms of position and exposure to winds) are also areas with Posidonia meadows. During field research conducted by Sunce, we record numerous trenches dug into the sediment and meadows caused by frequent anchoring, typically at depths of 12 to 15 meters. This indicates that the meadow is in very poor condition. Frequent anchoring, uprooting the seabed, and breaking off parts of the algea significantly contribute to the spread of invasive species, such as the algae Caulerpa cylindracea.
Why are ecological moorings better solution?
Anchoring pressure can be reduced by installing ecological moorings (still rare in Croatia) and by banning anchoring in Posidonia habitats outside permanent anchoring zones. France and Spain are positive examples of countries that have done the most in regulating anchoring over Posidonia meadows and establishing more environmentally friendly infrastructure.
Ecological moorings are directly “drilled” into the seabed, so their impact is smaller than the traditionally used colpo morto systems, which occupy a much larger seabed area. Today, many sailors have insufficient experience in mooring and anchoring, and they want the option to moor to buoys, for which they are willing to pay extra due to the security they provide.
– Developing small-scale ecological moorings infrastructure with minimal impact on the landscape and marine habitats should be an important part of the strategy for developing nautical infrastructure. On the one hand, to protect the marine environment, and on the other, to ensure the safety of sailors. Croatia finally has an official map of marine habitats that should serve for better spatial planning, surveillance and informing sailors,– says Špika.
The national marine habitat map was published earlier this year and covers 51% of the Adriatic, or 6,500 km², down to a depth of 40 meters, selected areas near national parks and nature parks, and two areas in the epicontinental zone, one of which is in the center of the Jabuka Pit.
We addressed the legislative and institutional framework related to free anchoring within the EFFICIENTN2K project. Also, the Interreg cross-border cooperation project BIOPRESSADRIA is currently underway between Italy and Croatia. Sunce and its partners are working to identify and assess the state of habitats and pressures related to nautical tourism in pilot areas in the Adriatic. The main goal is to implement a joint cross-border strategy to achieve practical solutions (such as ecological moorings) aimed at reducing the impact of coastal and nautical tourism on marine and coastal biodiversity.
Informing for positive change
Sailors are mostly people who love the sea and want to protect it. A significant part of the problem with the negative impact of anchoring lies in their lack of awareness about the importance and vulnerability of seagrass meadows and how to reduce the negative impact of anchoring. It is necessary to inform them and offer alternatives to anchoring in Posidonia meadows.
– We can see positive changes at the Spanish Balearic Islands, where, after introducing the ban on free anchoring over Posidonia meadows, local authorities spent three years conducting an informational campaign for sailors, with no intent to issue fines. Informing and educating preceded enforcement and fines, and within a few years, they reached a point where there are almost no boats in violation, meaning almost no freely anchored boats in Posidonia meadows, – says Špika.
Sunce has followed this example and this summer, as part of the And Where Do You Anchor? campaign and the Interreg EFFICIENTN2K project, conducted actions to inform sailors at Zlatni Rat and Šćedro.
– These actions showed us that many sailors are aware of the problem of free anchoring, especially those with experience sailing in France and Spain, where this issue has been addressed for many years. So, if bans on anchoring over highly valuable Posidonia meadows were introduced, many sailors in the Adriatic, we’re sure, would already understand why and be willing to comply, – says Zrnčić.
Until protection of this valuable species through anchoring regulations is strengthened, pay attention to where you anchor, advises Špika. If there is infrastructure, use it and avoid free anchoring. If you do anchor freely, make sure it’s not in Posidonia meadows. And to minimize your impact, drop and lift the anchor properly.
Five steps to a correct anchoring:
- Approach the anchoring place facing the wind and identify a clear bottom zone (sand bottom). Avoid anchoring in Posidonia meadows.
- Throw the anchor when the boat is stopped. Anchor has to suite the size of the boat.
- Release the anchor chain while slowly reversing. Make sure the chain doesn’t touch the Posidonia, as both the anchor and the chain have a negative impact.
- Wait until the bow turns into the direction of the wind and check if the anchor holds.
- Upon leaving, move the boat to the position directly above the anchor and then pull up the anchor.
We believe Croatia will soon become a positive example of protecting valuable Posidonia meadows in the Mediterranean. If you think this article should be read by other sailors or sea lovers, share it and help preserve the Adriatic!
