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

European marine and coastal areas are governed through complex policy landscapes where policy interplay occurs across multiple governance levels, policy areas, and geographical scales. Misalignments between policy objectives and measures along these dimensions generate policy incoherences, resulting in suboptimal tradeoffs and outcomes. This paper advances conceptual refinement and provides empirical validation of a prototype methodological framework designed to explain the structural drivers of policy (in)coherence in marine and coastal governance. The framework is organized around three explanatory factors: governmental organizations, the science-policy-society interface, and mechanisms for stakeholder involvement. Drawing on a systematic literature review, these factors were applied as an analytical lens to identify nuanced subcategories of archetypal patterns that characterize institutional barriers and enablers. Recurrent barriers include fragmented governance roles and limited coordination across the land-sea interface, while persistent enablers relate to harmonized data, knowledge-sharing platforms, stronger regional collaboration, and inclusive stakeholder engagement. Policy recommendations are also identified.