By Thierry Duchesne, FMES Maritime Department Director

Abstract: As we saw in a previous article, the Western Mediterranean is doing better in many areas. The actions undertaken from the 1970s onwards have borne fruit even if the efforts must not be relaxed.

Since then, new environmental challenges have emerged or intensified. The environmental fight continues. But for it to be effective, we must concentrate our efforts on the most relevant environmental priorities. On the eve of the United Nations Ocean Conference to be held from 9 to 13 June 2025 in Nice, it is essential that France prioritizes its new environmental priorities for the Mediterranean in order to further improve its ecological status and make it even more resilient.

Protecting coralligenes, taking into account ordinary biodiversity, monitoring and controlling the pressure of the most threatening invasive species, redefining marine protected areas and rebuilding fish stocks are the main priorities for the coming years.

Introduction

As described in a previous article, the Mediterranean has come a long way thanks to protection measures adopted since the 1970s, which have led to a marked improvement in the ecological status of this sea, at least for the French and European coasts.

Without relaxing our efforts on these protection measures already adopted, it is now necessary to relaunch a new dynamic around common objectives for environmental protection actors in the Mediterranean. The World Oceans Summit in Nice (June 2025) is an opportunity to “revisit” our environmental policy at sea and identify the new major challenges that must now be addressed with boldness and determination.

It is this work that was carried out on the occasion of the symposium “New challenges for environmental protection in the Mediterranean in the perspective of UNOC3” (April 18, 2025 – Marseille). Five main priorities were identified by the community of operational actors, scientists and environmental engineers who prepared and intervened in this event. These five new key priorities are: the conservation of key habitats such as coralligene, the recognition of ordinary biodiversity, the fight against the proliferation of certain invasive species, the real scope of marine protected areas and the regulation of fishing activities in the Mediterranean.

Of course, other environmental damage exists and has been identified (plastic pollution, chemical contaminants, noise or light pollution, etc.).  However, the reason they are not included in this list is that either the control policy is at a higher level than the local decision-makers or the scientific data are not yet supported by sufficient scientific evidence.

First priority: The protection of coralligenes, a new challenge for the coastal seabed

An emblematic habitat of the Mediterranean but still unknown, coralligene is a biological structure built over the centuries by limestone algae. This three-dimensional bioconstruction harbors remarkable biodiversity and plays an essential role in ecological regulation, oxygen production, carbon storage and support for small-scale fisheries. It is found in the form of vertical cliffs or massive plateaus, providing shelter to a wide variety of marine species. The area of the coralligene in the French Mediterranean sea floor represents only 5000 hectares with an approximate distribution of nearly 50% in Corsica, the other two quarters being distributed equitably between the PACA and Occitanie regions.

Despite its recognition as a habitat of Community interest by the European Union, coralligene is under threat. Its ecological status is deteriorating rapidly: in four years, out of the 38 water bodies studied, only 14 are in good condition, with a loss of 50% of the bodies in good condition since 2020. Among the major threats are global warming (increase in temperatures, appearance of heat algae) which favors the mortality of fixed species but also the sedimentation of these living structures linked to erosion, coastal work and artificial management of beaches (quarry sand producing sludge). Lost fishing gear, anchorages and damaged net deposits further exacerbate this pressure. Every year, nearly 50 hectares are impacted by anchors, jeopardizing the integrity of these fragile ecosystems.

Concrete measures to curb this decline are as follows: regulate fishing (including recreational fishing) on these habitats, make it mandatory to report and remove lost nets (for example, a financial incentive mechanism could encourage reporting) and prohibit anchoring activities, and discarded nets.

The second priority is to take account of ordinary biodiversity

The protection of marine biodiversity has long targeted the most visible or charismatic species, such as grouper, corb or large mother-of-pearl. But this focus has had the disadvantage of obscuring the ecological importance of the so-called “ordinary” biodiversity, consisting of less spectacular species but essential to the proper functioning of ecosystems. It is this discreet biodiversity, often ignored, that forms the backbone of food webs and conditions the resilience of environments.

The so-called “ordinary” biodiversity, although omnipresent in living spaces, suffers from a lack of recognition both scientific and political.  Ordinary biodiversity includes all those species that we have always seen without paying attention and that few people are able to simply name. These are “algae”, “small fish”, “small crabs” and “shellfish”…. The extreme banality of this biodiversity, which for most people is a vague concept, hinders its operationalization in public policies. However, as a component of everyday life, it represents a strategic lever to reconfigure the relationships between human societies and living environments. It offers an opportunity to think of biodiversity not as a distant or exceptional entity, but as an accessible, observable and shareable continuum.

This biodiversity is extremely diverse and complex, of different sizes and sometimes difficult to observe with the naked eye. To quantify it, we may need, in addition to the informed eye of the naturalist, the support of emerging tools to assess its ecological significance. Environmental DNA, autonomous visual sensors or artificial intelligence are increasingly making it possible to identify species and interactions that were previously invisible. These technologies reveal unsuspected biodiversity in areas once perceived as mundane, such as shoals, ports or anthropogenic areas.

Given its close links with the overall health of the marine environment, it is now essential to strengthen the consideration of “ordinary biodiversity” in conservation policies, including in ecological restoration criteria. It is a question of going beyond the logic of showcase (what have become a bit of marine protected areas) to integrate the real functional diversity of the different environments into management strategies.

By making our small seabed, our ports or our levees environmental issues, we can foster stronger public engagement with environmental issues. This perspective invites to go beyond a strictly utilitarian or heritage vision of biodiversity, by valuing the forms of attention, attachment and knowledge located. It also raises tensions: between protection and management, between perceived naturalness and effective anthropization, or between ecological diversity and intensive agricultural practices.

Faced with these challenges, the need for a common language and adapted tools to make this biodiversity visible and evaluable becomes crucial. This means breaking down the silos between disciplines and institutional frameworks, redefining assessment criteria and indicators and recognizing the central role of local authorities in the governance of living things. Thus understood, ordinary biodiversity is not only an ecological object, but also a democratic issue, calling for collective and political appropriation of the ordinary living.

Third priority: monitoring and controlling the pressure of the most threatening invasive species

The Mediterranean is today one of the world’s epicenters of the introduction of exotic species. Approximately 1100 introduced species of which around 10% are classified as invasive, i.e. capable of profoundly changing ecological and socio-economic balances. These introductions occur mainly via ballast water from ships (4 gigatonnes transported annually worldwide), aquaculture and shellfish farming, artificial canals such as the Suez canal, or accidental releases of domestic species.

Now, in the French Mediterranean, two species have become very problematic. It is the American blue crab (Callinectes sapidus) which causes considerable damage to the marine environment. It destroys nets, impacts local biodiversity by causing the disappearance of native species, hurts fishermen and jeopardizes the economic viability of small-scale fishing in certain regions (up to 80% loss of income for some fishermen, with especially severe consequences in Corsica). Another invasive species, the invasive seaweed Rugulopteryx (Rugulopteryx okamurae), introduced by aquaculture activities, produces significant biomass that, when stranded on the coast, releases toxic hydrogen sulfides that can cause health issues and alter benthic ecosystems.

Despite the existence of a European regulatory framework (2006 European regulation) and a national action plan, the institutional response is not up to the challenges. The lack of coordination, responsiveness and resources prevents effective prevention or control actions. Decisions are made too late. Given the threats posed by these species, it would be necessary to consider them truly as damage to the environment at sea requiring strong intervention measures, as in the case of the fight against pollution at sea. Thus, it is doubtless under the authority of the Maritime Prefect that control units should be set up to coordinate the action of the administrations in this field and the control operations at sea according to methodical plans.

Fourth priority: rethinking the network of marine protected areas

On paper, the Mediterranean coastline seems largely protected. The maps show a dense mesh of marine protected areas (MPAs) with nearly a hundred areas of this nature and 85% of the territorial sea classified as MPAs, plus 50% if we take all the maritime areas under French jurisdiction in the Mediterranean. That’s considerable. And not necessarily useful…

Several marine protected areas are experiencing real success with real effects on protected species. These are mainly nature reserves (Scandola, Bouches de Bonifacio, Cerbère-Banyuls) or the hearts of national parks (Port-Cros, Calanques), some of which have high levels of protection. But these categories of space actually represent less than 1% of the area of all marine protected areas. However, the health of our Mediterranean maritime areas has improved overall. However, if we look further into this matter, it is not so much the creation of all these MPAs as the adoption of general measures that have contributed to this improvement in the environmental status of the Mediterranean. Thus, the decision of the Mediterranean maritime prefect to ban anchorages on the seagrass beds of posidonia, a protected species, had a greater impact than the creation of all Natura 2000 zones dedicated to this marine plant (before the 2019 order of the maritime prefect, a ship of more than 24 meters could anchor on posidonia even in the protection zones of this species such as the Natura 2000 zones…). On another note, the PACA regional prefect’s ban on fishing for grouper and grouper throughout the Mediterranean has done much more for these species than protecting them in some MPAs. The cessation of anarchic concreting and the improvement of the quality of the water discharged to the sea were much more decisive for the return to a good ecological state of the Mediterranean.

It has become necessary to rethink marine protected areas to truly adapt them to needs. Currently, the race for land and the multiplication of administrative statutes (up to 18 different types if we include fishing cantonments then erected as “Marine Reserves”) has diluted the effectiveness of protection efforts (what to watch when everything is protected?) and has, in the end, worked against France. By displaying protection zones that do not comply with IUCN rules, France is now being pilloried by non-governmental organizations for making only “paper marine areas”. However, this accusation is unfair because, as we have already seen, France has conducted an environmental policy in the Mediterranean which is undoubtedly one of the most exemplary in comparison with the other states bordering this sea.

So, what should be done?

Certainly not aggravating the evil by adopting a policy of forward flight with the creation of an additional layer of MPAs that are “strong protection zones”. It is no doubt necessary, from now on, to pause and reassess these devices in terms of their actual ecological effectiveness and not just their regulatory display. We must also have the courage to merge our administrative categories of marine protected areas into those officially recognized by IUCN and the European Union so as not to complicate the legibility of these areas.

Many of these areas are the result of political compromises between local actors, with no real ecological basis. The connectivity criterion, which would ensure consistency between MPAs, should be applied as this was rarely used when designating them.

Other proposals also emerge to clarify the framework for action: limit the use of the term “protected” to areas under strict protection, strengthen the scientific monitoring of actions carried out, and involve researchers more in the governance of MPAs, scientifically assess the effects of management plans. It would also make sense to create continuous no-take bands, including different habitats, to ensure safe havens where biodiversity can be maintained freely.

Fifth priority: Fisheries in the Mediterranean, still a major challenge given the still strong pressure on the species caught

Fishing is an essential activity. It is a noble profession that nourishes men. It is essential to our future and well managed it guarantees the quality of maritime spaces. But a fishery that is too “impactful” on the environment destroys its environment and its economic model. Fishermen have already made significant efforts to adapt. But the journey is far from complete.

Because the Mediterranean is always concerned by overfishing, whether it is professional or recreational. Using 2023 statistics, only 2% of fish population landings on France’s Mediterranean coast concern species that are classified as being in good ecological status. Among these, the mud mullet of the Gulf of Lion, up to 2%.

In 2022, 34% of French landings in the Mediterranean come from stocks known as “replenishable or in the process of being replenished”. This category includes Mediterranean bluefin tuna (29%), anchovy from the Gulf of Lion (5%), sardine from the Gulf of Lion (1%) and, finally, swordfish (less than 1%). However, other species fished belong to the category of “collapsed” such as the hake of the Gulf of Lions or the eel.

Several factors explain the deterioration of fisheries in the Mediterranean. There is of course global warming but also the change and depletion of nutrients in water and various human causes.

The situation of fish stocks, particularly in the Gulf of Lion, illustrates the limitations of the current management system. Despite successive plans to reduce fishing effort, overexploitation persists, particularly for long-lived species such as hake. The conclusion is clear: stocks are not recovering, partly because of the low selectivity of fishing gear, in particular small-mesh trawls.

Fishing pressure remains too high on juveniles, which prevents natural renewal of populations. Simulations show that a simple enlargement of the trawl mesh size could significantly reduce the catch of undersized fish, with visible economic benefits as early as the third year. However, this simple and documented measure is still not implemented.

Faced with this situation, Europe has introduced a new management plan (WestMed 2), proposing a drastic reduction in fishing effort, unless alternative measures are adopted. However, the choices made by professional representatives tend to favor spatial closures rather than a real transformation of practices. The result is a superimposition of already complex zoning, without the ecological gains being guaranteed.

It is necessary to get out of this short-termist logic. The sustainability of Mediterranean fisheries depends on a thorough adaptation of techniques, better selectivity, and management based on robust indicators. Without this, social and economic tensions are likely to worsen, with no benefit to ecosystems.

Pressure on marine species is also exerted, in a significant way, by recreational fishing, which is poorly evaluated and poorly controlled in the Mediterranean. Several studies show, however, that the take-offs from species are not negligible and that they are sometimes higher than the professional fishing. In 2023, recreational fishers agreed that they were facing a decline in the resource over the past five years. A follow-up study carried out in the Marine Natural Park of the Gulf of Lion by CEFREM (University of Perpignan Via Domitia) over the period 2005 – 2015 showed a 56% decrease in the number of fish caught by recreational fishing.

Other studies have shown that this recreational fishery not only has a significant impact on vulnerable species but can also contribute to the introduction and spread of pathogenic and alien organisms (bait) and harm the marine environment with the loss of fishing lines, lead or lures often made of plastic. It is now extremely important to better control the quantities caught per recreational fisherman, as already exists in fresh waters, in order to reduce the pressure on species. It is this courageous policy of regulating the quantities taken that was adopted in February 2024 in the Marine Natural Park of the Gulf of Lion and the Calanques National Park. Two decrees signed by the regional prefect Provence Alpes Côte (Interregional Directorate of the Mediterranean Sea) regulate recreational fishing with the implementation of important measures such as quotas by species, minimum sizes or biological rest periods. Or, to follow the example of the Bouches-de-Bonifacio nature reserve where recreational fishing is strictly regulated by an authorization whose counterpart is mandatory information on catches. These experimental measures are exactly what could be recommended and will provide a better understanding of the impact of such regulations.

Conclusion

The French Mediterranean has recovered significantly back since its announced death in the 1970s. Major steps have been taken. But now we cannot remain at a crossroads. The Mediterranean needs a new environmental impetus. This momentum could be built on these five new key environmental priorities in the Mediterranean. Common projects and challenges are needed to create the dynamics that serve the major causes.