The state of Atlantic North sea bass stocks has evolved between 2015 and 2025. France has built one of Europe’s densest marine protection architectures. Species displacement can create a gap with historically fixed quota distribution keys, despite annual revision of many TACs.
The essentials
- Classical regulation produces measurable results: +35% for sea bass in the Atlantic North, +22% for cod in French EEZ between 2015 and 2025 (IFREMER).
- More than 20% of French territorial waters are now classified as marine protected areas, against a European target of 30% by 2030.
- The challenge is no longer merely regulatory: ocean warming is shifting species northward and deeper, rendering certain quotas obsolete before even their revision.
- Iceland and New Zealand have achieved faster rebounds with transferable quotas, but at the cost of ownership concentration that France has chosen to avoid.
- The tension between ecological efficiency and social equity will shape the next arbitrations of French maritime policy by 2030.
The rebounds are real, and that is the first thing to keep in mind
Between 2015 and 2025, the state of European sea bass in the Atlantic North has evolved. These changes are part of a decade of regulatory management.
Management decisions, such as multiannual management plans defined within the reformed Common Fisheries Policy of 2013, restrictions on catches during spawning periods, and seasonal closures of sensitive areas, can contribute to stock recovery. Behind each percentage of recovery are shipowners who accepted shorter seasons, coastal fishermen who adapted to stricter rules, IFREMER scientists who maintained the time series on which the entire system rests.
France has also built a protection architecture that goes beyond quotas alone. The network of marine protected areas covers a significant share of maritime waters under French jurisdiction, while the European target is 30% by 2030. These areas do not all constitute strict protection: some of them tolerate uses compatible with artisanal fishing. But certain actually protected marine reserves can export adults or larvae to adjacent fishing zones, under favorable ecological and management conditions.
Quotas and protected areas are complementary tools whose effectiveness depends on their design, implementation, and ecological context.
Species redistribute themselves according to temperatures
The problem emerges here. While regulation protects populations in defined zones, the ocean warms and species move.
Sea bass distribution can shift northward and deeper. The distribution of Mediterranean species can shift along Breton coasts. The distribution of boreal species such as saithe can shift. These migrations follow no administrative calendar: they occur according to the thermocline, not according to European regulation.
Distribution shifts can create or amplify gaps between biological units and management boundaries; the extent and evolution of these difficulties must be established stock by stock. A significant population shift can make the management zone and quota-sharing key inadequate, without necessarily rendering the overall quota useless. A marine protected area delineated to preserve a spawning ground may lose relevance if the target species reproduces in other areas.
Thermophilic species may see their distribution evolve with warming. TACs are generally fixed annually; multiannual plans do not obey a general revision periodicity of five to ten years. Yet for certain species, the shifts observed over ten years are already substantial. Species displacement can create a gap between historically fixed distribution keys and the current distribution of stocks, despite periodic revision of TACs.
Improvements are observed for certain stocks and indicators, notably for European sea bass, but they must be specified stock by stock. The two coexist, and distinguishing them requires a monitoring capacity that not all EU Member States possess at the same level.
The French choice facing the Icelandic model
Iceland and New Zealand have systems of transferable quotas, that is, fishing rights that are transferable on the market. These systems are part of their fisheries management, without demonstration here that they alone explain stock rebounds.
In a transferable quota system, each shipowner receives a share of the total allowable catch that they can sell, lease, or buy.
The ecological, economic, and social effects of transferable quota systems require specific studies.
French and European policy includes instruments of support and protection for small coastal fishing, without constituting a general and watertight separation from industrial fishing. The effects of these rules on stock recovery and necessary adaptability require specific evaluations.
The real arbitration is not between efficiency and equity as if these were two incompatible values. It is about knowing what level of slowness in stock recovery is acceptable to maintain a social structure of fishing. And as climate accelerates transformations, the margin of tolerance for this slowness shrinks.
France accounts for 73% of the EU’s bird species: what this reveals about blind spots
Birds can provide complementary indicators of marine ecosystem health and prey availability, but they do not replace stock assessments. Populations of northern gannets, common terns, Atlantic puffins depend directly on the availability of forage fish—sprats, anchovies, sand eels—that industrial fishing and climate variations affect simultaneously. When forage fish become scarce or shift, seabirds can reflect these changes.
The avian diversity present in France makes it a useful observatory for the ecosystem effects of fishing and climate change. IFREMER and marine protected area managers have begun integrating these biological indicators into their monitoring protocols, an approach called “ecosystem-based” that goes beyond managing species by species to focus on food chain equilibria.
This approach is more complex to administer, but it is more robust against climate change. Management that ignores trophic interactions can increase the risk of error and reduce management robustness; an ecosystem-based approach is recommended. Avian monitoring are complementary ecosystem indicators to catches, scientific surveys at sea, and other biological and environmental data.
Regulating a moving target
The coming years will pose a challenge that is both methodological and political: adapting a regulatory architecture designed to manage stable populations to a system that reorganizes in real time.
Several avenues are being explored. IFREMER is working on prospective distribution models that integrate climate scenarios into stock projections. The idea is to anticipate species shifts and adjust management zones before populations have already migrated, rather than after. This is a major shift in the temporality of how regulation is conceived.
A second avenue concerns quota flexibility. Several researchers advocate for annual revision mechanisms on certain highly mobile species, rather than fixed multiannual plans. This requires a near-real-time monitoring capacity, catch data reported quickly, more frequent assessment campaigns, which implies investments in fisheries information systems.
A third avenue concerns the economic uses of fishing. Pilot programs in certain Atlantic regions are exploring models where fishermen participate in collecting scientific data, creating supplementary income while improving monitoring quality. This is a way of linking the economic interest of fishing professionals to the quality of information on which their own regulation rests. As shown by economic transformations in other sectors facing new environmental constraints, the most sustainable adjustments are those that align the incentives of actors with collective objectives.
The European target of 30% marine protected areas by 2030 provides a framework. But the quality of protection matters as much as the area covered. A protected area on paper that tolerates destructive practices protects nothing. France will have to arbitrate, in the coming years, between the quantitative expansion of the network and the qualitative strengthening of existing zones, two objectives that are not necessarily compatible with constant resources.
The limits of stock rebounds
Indicators for European sea bass have improved compared to the mid-2010s; any conclusion on cod must specify the ICES stock in question and rely on its assessment. They confirm that well-designed and well-implemented regulation can reverse degradation trends that seemed structural. On this point, optimism is justified by the data.
But a stock rebound in a given geographical area does not guarantee long-term stability if the conditions that permitted this rebound change faster than the regulation. Species that recovered under a certain thermal regime could find themselves under pressure again in ten years, not from overfishing, but from mismatch between their optimal habitat and available temperatures.
The French model can contribute to ecological results. The next step is to demonstrate that it can maintain them in a changing environment, and for that, monitoring, enforcement of rules, adaptive revisions, and integration of climate data are important complements to quotas in fisheries management.
The challenge is not to choose between stock protection and climate adaptation. It is to build a regulation that does both at the same time, without sacrificing the social equilibria that give French artisanal fishing its legitimacy and resilience. The countries that solve this equation first will provide the model that others adopt.
Sources
- European Biodiversity Information System, France Sheet
- IFREMER, Annual Reports 2026 on the State of Fish Stocks (ifremer.fr)
- OBIS Ocean Biodiversity Information System, marine species distribution data (obis.org)
- European Commission, Common Fisheries Policy, 2013 revision and multiannual framework (ec.europa.eu/fisheries)
- European Commission, Strategy for Biodiversity 2030, 30% marine protected areas target (ec.europa.eu/environment/strategy/biodiversity-strategy-2030)