The research team conducted a systematic literature review following the PRISMA 2020 guidelines, searching the Web of Science and Scopus databases for peer-reviewed studies published between January 2014 and February 2024. The lower bound of the timeframe was chosen deliberately: 2014 marked the implementation of the EU Maritime Spatial Planning Directive, a major revision of how European seas are governed. After a two-stage screening process that narrowed 1,444 identified studies down to 72 relevant papers, the researchers applied a structured analytical framework organized around three explanatory factors: governmental organizations, the science-policy-society interface, and stakeholder involvement mechanisms. Each factor was used as a deductive coding category to identify barriers and enablers, which were then refined into inductive archetypes capturing recurring patterns at a moderate level of abstraction.

The framework itself builds on the Policy Coherence Framework developed under the Horizon Europe CrossGov project, which defines policy coherence as the extent to which policies strengthen each other by promoting synergies or reducing conflicts between objectives and measures, both in design and during implementation. The authors argue that the implementation phase deserves particular attention in multilevel governance contexts like Europe’s, where EU-level instruments are transposed and applied at national and sub-national levels with varying capacities, priorities, and institutional arrangements. It is here, they contend, that abstract policy objectives are translated into practice — requiring interpretation, prioritization, and coordination among sectoral interests — and where incoherences become visible and are either mitigated or exacerbated.

Among the most frequently cited barriers are unclear mandates and roles across governmental organizations. Coastal areas, in particular, suffer from overlapping or competing responsibilities, with management duties frequently split between organizations that separate land from sea. The review documents cases where the absence of a clear leading authority produced fragmented and uncoordinated efforts, and where ambiguity about financial responsibility for management interventions left critical infrastructure unfunded. In England, the review notes, assigning strategic oversight of flood risk management to the Environment Agency helped align dispersed planning — but only because the designation was accompanied by collaboration with local authorities and their expertise. In Sweden, by contrast, the establishment of a combined marine and freshwater agency achieved limited success due to a lack of leadership and insufficient integration of freshwater issues, illustrating that structural reorganization must be accompanied by clearly defined responsibilities.

Coordination mechanisms emerge as the single most discussed attribute in the entire review, appearing frequently in relation to both barriers and enablers. The absence of adequate coordinating bodies — particularly at the transboundary level — hampers cross-border marine spatial planning and the implementation of the Marine Strategy Framework Directive. The Regional Seas Conventions, such as HELCOM in the Baltic Sea, are recognized as important venues for transboundary cooperation, and the formalized partnership between HELCOM and VASAB is highlighted as a model. The EU has enhanced its interactions with HELCOM by adopting a dedicated Strategy for the Baltic Sea Region, promoting synergies between EU legislation and regional cooperation. Yet the review also warns that adding coordination layers to already fragmented frameworks is not easily resolved, due to path dependencies and unresolved fragmentation issues that persist beneath new institutional arrangements.

The land-sea interface presents a particularly stubborn divide. The review identifies a significant separation between the EU’s freshwater instruments, governed by the Water Framework Directive, and its marine instruments, governed by the Marine Strategy Framework Directive. These directives apply to different geographical scales and timelines and lack a unified coordination structure, posing a barrier to coherent water management from source to sea. Ecological boundaries rarely match administrative ones, and the review documents how this mismatch produces overlapping responsibilities or governance gaps, especially where policy instruments are designed and applied on only one side of the administrative divide. Land-based activities that generate runoff and pollution substantially impact coastal and marine ecosystems, yet these interdependencies are often inadequately addressed in policy frameworks, leading to fragmented efforts in resolving interconnected issues.

Fragmented data and knowledge constitute the second most cited barrier category. Evidence-based decision-making is challenged when data is unavailable, dispersed across organizations and formats, or divided along the boundaries of disciplines, sectors, and geographical scales. Several EU directives set out their own systems for data collection, which not only fragments knowledge but also places high pressure on scientific advisory systems. The lack of harmonized cross-border data sources poses particular challenges for transboundary marine spatial planning. The review identifies enablers including comprehensive data availability through open-access portals, integrated data collection systems across legal frameworks, shared and standardized cross-border data and tools, and permanent knowledge transfer platforms such as partnerships, networks, and information centers that support dialogue between knowledge providers, decision makers, and other stakeholders.

Stakeholder involvement mechanisms are both a prerequisite and a challenge for policy coherence. The review identifies uneven stakeholder engagement — where certain groups lack representation, are involved late in processes, or face power imbalances — as the largest barrier in this category. Formalized mechanisms such as partnerships, coalitions, and guidelines are highlighted as enablers, with examples including the Severn Estuary Partnership, the Baltic Environmental Forum, and the Dutch North Sea Dialogues and Agreement. Yet the review also cautions that stakeholder inclusion may enhance legitimacy while simultaneously increasing transaction costs and slowing decision-making. The Dutch North Sea Agreement illustrates this tension: although established to address coordination challenges among governmental organizations and stakeholders, the process has been shown to be strongly influenced by the offshore wind sector, shaping marine spatial planning outcomes in ways that privilege sector-specific objectives over broader integrative goals.

The review emphasizes that institutional attributes cannot be assessed in isolation from their governance context. Coordination mechanisms, frequently recommended as tools to enhance policy coherence, may reinforce the dominance of specific sectoral interests when they operate within settings characterized by strong power asymmetries. In Ireland, the establishment of the Marine Coordination Group did not fully resolve fragmentation, as its limited authority and persistent sectoral silos continued to hinder integrated decision-making. The archetype approach adopted by the researchers seeks to balance generalization with sensitivity to context, treating identified patterns as general building blocks rather than universally applicable principles. The barriers and enablers should not be interpreted as fixed or binary categories, the authors stress, but rather as existing along a continuum where their role may shift depending on how they interact with other institutional attributes and contextual conditions.

As climate pressures intensify and human uses of marine and coastal areas continue to expand, the consequences of fragmented and incoherent governance frameworks are becoming increasingly severe. The review concludes that achieving policy coherence in European marine and coastal governance is an urgent structural and institutional priority, and that the archetype framework offers policymakers and researchers a practical approach to move beyond general calls for integration toward targeted and context-sensitive interventions. With ongoing efforts to consolidate European marine governance — particularly through the Ocean Pact and the forthcoming Oceans Act — the importance of strengthening policy coherence has been repeatedly emphasized by the EU. The categories presented in this framework, the authors argue, can provide a valuable foundation for informing those policy discussions, offering a structured analytical approach to addressing the underlying root causes of incoherence rather than merely its symptoms.

Subject of Research: Archetypical patterns of barriers and enablers to policy coherence in European marine and coastal governance: a systematic review

Article Title: Archetypical patterns of barriers and enablers to policy coherence in European marine and coastal governance: a systematic review

Article References: Trubbach, S., Johannesen, E., & Platjouw, F. M. (2026). Archetypical patterns of barriers and enablers to policy coherence in European marine and coastal governance: a systematic review. Frontiers in Ocean Sustainability, 4, Article 1768173. https://doi.org/10.3389/focsu.2026.1768173

Image Credits: AI Generated

DOI: 10.3389/focsu.2026.1768173

Keywords: Archetypical, patterns, barriers, enablers, policy, coherence, European, marine, coastal, governance, systematic, review