UNCLOS introduced Exclusive Economic Zones (EEZ) as an instrument for the management of marine areas assigned to the jurisdiction of national States and Sovereignties. EEZ define spatial extents at surface level, without consideration of the shape of the sea bottom or of the height of the water column. In our contribution we explore volume as a new tool for marine planning. We first calculate the volume of water corresponding to each State's current EEZ. We compare the ranking of countries based on EEZ surface with the ranking based on the corresponding volume, and we analyze the movements in the respective rankings. In order to define volumes we then propose a parameter (cross-sectional area) that is analogous to the distance from baseline used for defining EEZ's surfaces,, we propose a constant value for the area of A that is analogous to the 200 nautical miles constant used for calculating EEZ's surfaces. Using this concept, we show the differential impact of local bathimetries on the volumes of water that could fall under national jurisdictions. These volumes differ in general from those currently underlying EEZ. We eventually propose the new precisely defined notion of Exclusive Economic Volumes (EEV) and we draw the surface boundaries of the resulting managed spaces according to two alternate methods: actual local bathimetry and average bathimetry.

As with land territory and EEZ, Exclusive Economic Volume is a rough, prima facie indicator of the wealth of a nation and of the scope of its stewardship on the biological riches inhabiting it. Its calculation highlights geographic and historical imbalances, as well as challenges for biodiversity protection. Decoupling volume from surface in the spatial analysis of the ocean shows other aspects of those imbalances, and hints as ways to correct them and to fine-tune the instruments for addressing protection challenges.

How to cite: Casati, R., Raimondo, S., Esteban-Cantillo, J., and Schmidt di Friedberg, M.: Exclusive Economic Volumes: Enriching the palette of tools for Marine Spatial Planning, One Ocean Science Congress 2025, Nice, France, 3–6 Jun 2025, OOS2025-137, https://doi.org/10.5194/oos2025-137, 2025.

In recent decades, the conservation of marine ecosystems has garnered global attention due to the substantial evidence of ocean degradation and biodiversity loss. Despite significant advances in marine science, a comprehensive understanding and adequate protection of marine environments still need to be improved. Marine ecosystems face cumulative anthropogenic pressures, both locally and globally, including overfishing, pollution, and climate change, which diminish biodiversity and degrade ecosystem services essential for food security, carbon storage, and climate regulation. As a response, Marine Protected Areas (MPAs) have emerged as a primary conservation tool under frameworks such as the Convention on Biological Diversity (CBD) and the recent High Seas Treaty. However, the effectiveness of Marine Conservation Strategies (MCSs) is debated due to several factors. These include remote locations, unclear zoning, and poor delimitation (14%), lack of regulations or contradictory regulations (8%), lack of stakeholder involvement (7%), global warming or warming waters (7%), and weak governance or coordination (6%). These issues are the main drivers of inefficacy, often leading to these strategies being labeled as "paper parks" which are protected areas in name only.

This study provides a systematic literature review (n=225, among 1772 articles) of the effectiveness of Marine Conservation Strategies (MCSs) in addressing the challenges posed by these drivers of ecosystem and biodiversity loss, considering that we currently have different spatial management tools to conserve marine ecosystems. We examine the diverse conservation strategies, comparing their strengths, limitations, and interactions within marine spatial planning frameworks. By synthesizing existing literature and identifying research gaps, this review aims to support the development of adaptive and dynamic conservation tools that align with the Kunming-Montreal Global Biodiversity Framework and the Biodiversity Beyond National Jurisdiction (BBNJ) agreement. Our findings underscore the necessity for multifaceted, resilient conservation strategies, considering the temporal and spatial scales with repercussions in the functional scale, that can adapt to the evolving natural dynamism of marine ecosystems, ensuring long-term sustainability and resilience.

How to cite: Esteban-Cantillo, O. J., Quesada, B., Eveillard, D., and Casati, R.: Evaluating the effectiveness of Marine Conservation Strategies: challenges for sustainable ocean management , One Ocean Science Congress 2025, Nice, France, 3–6 Jun 2025, OOS2025-153, https://doi.org/10.5194/oos2025-153, 2025.

Marine ecosystems are facing more anthropogenic pressures than ever before, and the ecosystem-based approach (EbA) is recognized as the best practice for managing multiple ocean-use sectors, because it addresses their cumulative impacts on ecosystem components and looks at respective trade-offs. Ecosystem-based management (EBM) is however portrayed as too complex to be fully implemented, and tackling existing challenges is key to achieving the Sustainable Development Goals (SDGs). Marine spatial planning (MSP), being a process that has the potential to balance demands for ocean space with environmental protection, is increasingly considered crucial for achieving global ocean goals.This study was conducted at the Diapontia plateau in the Ionian Sea, representing a rather pristine natural environment; part of the area is a Natura 2000 site for migrating birds, while other conservation priority species, such as the loggerhead turtles and the monk seals, exist there. Regarding human activities, transport services connecting the Islands with Corfu, fishing and particularly small scale that is conducted by the few fishers inhabiting the islets, as well as recreational boating during summer months are those that mainly take place. In this rather unspoilt environment, there are official plans for the establishment of an offshore wind farm (OWF) that will promote the islands’ energy self-sufficiency, in line with prerequisites set by the EU Green Deal. The strategic environmental assessment that was conducted to accommodate OWF planning in Greek waters was based on broad-scale low-resolution data, and in fact, the latter is one of the reasons, proclaimed by the local communities for being against the establishment of the specific OWF. Hence, the aim of this effort was to investigate potential conflicts between key ecosystem components and the future use of energy production via the proposed OWF. In this vein, the Netica Bayesian Network (BN) software has been applied to investigate potential conflicts and/or synergies. The BN Network analyzes the aforementioned interactions as a function of the intensity of sea uses existing at a properly defined spatial scale and the sensitivity of the respective ecosystem components to those uses. Indeed, as both data accuracy and resolution influence the interpretation of cumulative impact assessment (CIA) outcomes, the results reflecting the relative extent of potential impacts may differ depending on the scale and spatial resolution used in the assessment. What is more, spatial interactions among existing uses and the potential installation of the OWF were explored through spatial analysis, in the frame of which, each activity has been characterized by a set of factors including its vertical, spatial, and temporal scale and whether it is mobile or fixed. Outcomes, based on the application of the aforementioned decision support tools (DSTs) contribute to filling fine-scale analysis gaps, elucidating thus potential interactions with conservation priority habitats/species, as well as between uses competing for the same marine space. Robust scientific advice, stemming from efforts linked to the effective implementation of the EU MSP Directive, is crucial for developing comprehensive tailor-made spatial plans, based on the respective characteristics of social-ecological systems, promoting the EbA in decision-making.

How to cite: Katikas, L. and Vassilopoulou, V.: Using Decision Support Tools for effective planning of sea uses under an Ecosystem-based Approach, One Ocean Science Congress 2025, Nice, France, 3–6 Jun 2025, OOS2025-209, https://doi.org/10.5194/oos2025-209, 2025.

The United Republic of Tanzania is endowed with a vast marine territory, encompassing a territorial sea of 64,000 square kilometers and an Exclusive Economic Zone of 223,000 square kilometers, alongside a diverse coastline that stretches 1,424 kilometers. This space is characterized by a rich variety of coastal and marine ecosystems, including coral reefs, seagrass beds, mangroves, sandy beaches, rocky shores, and numerous islets, collectively covering approximately 241,500 square kilometers about 20% of Tanzania's total land area. These ecosystems provide essential goods and services that support local communities' livelihoods and cultural practices, hosting remarkable biodiversity, including 150 coral species, 8,000 invertebrate species, 1,000 fish species, 5 marine turtle species, and various other marine organisms.

Despite significant progress in conservation, with 33.5% of terrestrial areas and 6.5% of ocean areas under protection, Tanzania faces pressing challenges in conservation critical habitats. To meet international commitments, efforts must intensify to ensure that at least 30% of these habitats are protected by 2030 as per target three of the Kunming Montreal Global Biodiversity Framework.

The blue economy resources of Tanzania, which include fisheries, tourism, and aquaculture, are increasingly threatened by climate change and various environmental, social, and economic stressors. These challenges lead to habitat degradation and create uncertainties for coastal communities, ultimately compromising the national economy. In response, the Government of Tanzania is implementing Marine Spatial Planning, a comprehensive public process that analyzes and allocates the spatial and temporal distribution of human activities in marine areas to achieve ecological, economic, and social objectives. A scoping study conducted between July 2022 and June 2023 involved consultations with over 314 stakeholders, focusing on policy, legal, and administrative analyses, as well as a spatial data audit. This study laid a strong foundation for full-scale MSP in Tanzania, revealing eight sectoral scopes for consideration and resulting in 23 recommendations to strengthen the blue economy.

Following the scoping phase, Tanzania has made significant strides in marine spatial planning and biodiversity conservation, including the development of National Marine Spatial Planning Guidelines and a Blue Economy Policy with a 10-year strategy. This talk will outline the progress made to date in this East African state, unique challenges, and lessons learned.

How to cite: Mpina, E., Roberts, J., Rubens, J., Jirmo, T., Hayes, D., Jumbe, A., Maganga, M., Magembe, L., and Ardron, J.: Strengthening the Blue Economy in the United Republic of Tanzania through Marine Spatial Planning and Biodiversity Protection, One Ocean Science Congress 2025, Nice, France, 3–6 Jun 2025, OOS2025-251, https://doi.org/10.5194/oos2025-251, 2025.

Marine regulations can be a maze: different rules, overlapping protections, and gaps that aren’t always clear. ProtectedSeas Navigator helps make sense of it all by pulling together this information into one global platform. While hundreds of nations have committed to the global 30x30 target, much work remains not only to reach that goal, but to also sustainably manage the remaining 70%. Regulatory protections are crucial for marine management efficacy, and accurate data on in-place management measures are essential for assessing existing marine protections and informing the creation of new areas. However, collecting and interpreting marine regulations can be challenging due to often unavailable or difficult-to-access legal instruments. Overlapping measures and siloed management add further complexities.

ProtectedSeas Navigator contains data on worldwide regulations for MPAs, fishery management areas, and other place-based marine managed areas (MMAs), including site-specific information for each boundary, bringing much-needed transparency to understanding existing ocean management. It includes regulations for over 22,000 marine areas in more than 200 countries including MPAs and potential OECMs like fisheries management areas. 

Using Navigator, we assessed regulatory data cumulatively across overlapping areas using spatial aggregation techniques to provide insights into overall protection of ocean spaces achieved through overlapping jurisdictions. We will present multiple case studies from this analysis to illustrate how a more holistic view of ocean management reveals both hidden gaps and hidden strengths in protection.

For example, in a hex grid analysis of Mexican marine waters, Navigator found up to 13 more MMAs in any given ocean space hex cell, compared to the areas available in the World Database on Protected Areas. But, based on this analysis, only roughly 47% of the ocean area within MPAs in Mexico were found to be highly protected from fishing, demonstrating a large variability of legal protections that exist within these MPAs. When looking at legal marine protections in the Mexican ocean area outside of MPAs, a small area was found to be highly protected from fishing through overlapping MMAs, including vessel restricted areas. 

Analyses in U.S. marine waters revealed several ocean spaces where individual place-based marine protections were minimal, yet when combined with protections from other overlapping managed areas, resulted in more highly regulated spaces with enhanced protection compared to some official MPAs.

More accurate evaluations of in-place marine protections, cumulatively across ocean spaces, allows the conservation community and management agencies to have a more comprehensive and multi-jurisdictional view of spatial management and work toward sustainable management of their entire ocean space, while also meeting global conservation targets.

How to cite: Vincent, T. and Sletten, J.: A global regulation-based tool for marine protection assessments and planning for 100% of our ocean, One Ocean Science Congress 2025, Nice, France, 3–6 Jun 2025, OOS2025-376, https://doi.org/10.5194/oos2025-376, 2025.

With escalating pressures from diverse human activities, marine environments are increasingly threatened by cumulative impacts such as biodiversity loss, habitat degradation, and fish stock decline, putting ecosystem sustainability at risk. This research introduces a comprehensive framework to manage and counter these impacts, using data-driven ecological modeling tools to realistically capture marine ecosystems' responses to complex human-induced pressures, thereby supporting informed and effective decision-making. At the core of this approach is the PlanWise4Blue tool, now adapted within the BlueGreen Governance Dashboard, which offers a web-based platform for stakeholders to assess the environmental impacts of multiple plausible management scenarios. The PlanWise4Blue tool stands out by uniquely assessing the synergistic effects of multiple human pressures on natural assets. Moreover, it goes beyond simple score-based assessments to provide numeric evaluations grounded in scientific literature. Unlike traditional tools that yield arbitrary indices, PlanWise4Blue delivers precise calculations of the actual losses and gains in natural assets, making it a powerful resource for evidence-based, sustainable planning. Developed in collaboration with stakeholders, this tool empowers users to select strategies that minimize ecological harm and promote marine ecosystem resilience. Applied case studies illustrate how PlanWise4Blue addresses critical data gaps and fosters transparent governance in marine management. By enhancing stakeholder engagement and policy efficacy, this framework supports sustainable marine governance, aligning ecological preservation with policy objectives.

How to cite: Kotta, J., Vollmer, E., Fetissov, M., Furlan, E., Grassi, G., Zennaro, F., Orav-Kotta, H., and Pagan, H. C.: Advancing marine management: a synergistic approach to cumulative impact assessment with PlanWise4Blue, One Ocean Science Congress 2025, Nice, France, 3–6 Jun 2025, OOS2025-644, https://doi.org/10.5194/oos2025-644, 2025.

The European Union's Maritime Spatial Planning (MSP) Directive mandates the implementation of MSP in all EU member states by 2021. As a result, MSP is being defined across European seas, making it crucial to assess how it is being integrated and how it might be further tailored to specific geographic contexts. Yet, adapting MSP to regional specificities is essential to ensure effective, place-based management of marine spaces. This need is particularly pronounced in the marine areas off the coast of large cities, where diverse and dense maritime activities converge. However, the application of MSP in such context remains an underexplored topic in research.

This study aims to investigate how MSP is perceived by local stakeholders, to shed light on the main challenges and levers that might be relevant for its implementation in a large coastal city. This was achieved through a survey and a participatory mapping workshop conducted with stakeholders from Marseille, selected as case study of a large coastal city located in one of the EU's most heavily used marine regions, the Mediterranean Sea. The methodology employed and the key findings will be presented.

How to cite: Fabbri, F., Ruitton, S., and Robert, S.: Challenges and levers for developing Maritime Spatial Planning off the coast of a large Mediterranean city, One Ocean Science Congress 2025, Nice, France, 3–6 Jun 2025, OOS2025-662, https://doi.org/10.5194/oos2025-662, 2025.

For several years, research studies have shown that anthropogenic activities can impact the environment. It is therefore essential to understand how environmental stressors may influence ecosystems and biodiversity, especially in industrial and/or port areas where many activities are cooccurring. From a perspective of sustainable development, economic development and diversification of industrial port areas are essential to maintain a stable economy, and it is imperative that decision-makers have access to scientific support adapted to their specific needs, allowing them to ensure the preservation of terrestrial and marine ecosystems, as well as the health of communities and workers. In addition, considering that the majority of industrial port areas are located close to urban areas, a management model integrating data at a high resolution becomes essential.

Twenty years ago, impacts of industrial development within and outside industrial-port areas attracted little attention from the population, and information capacity was limited by the tools of that time. Nowadays however, social acceptability requires transparency and communication of environmental information involving actors with a neutral point of view and a scientific credibility. In this context, INREST has developed a preventive environmental management tool, the Enviro-Actions Model, that integrates collection and transmission of big data in near real-time using artificial intelligence for data analysis as well as the transmission of preventive alerts to stakeholders at different levels. These actions allow environmental management to act in a prevention mode rather than after possible perturbations have occurred. This model is being implemented in Quebec (Canada), in the Port of Sept-Îles, the largest mineral port in North America and the second among Canadian ports in terms of annual volume of operations, and in the Port of Saguenay and Rio Tinto Saguenay. With successful deployments since its creation, the Enviro-Actions Model is proposed to other harbour administrations within and outside Canada, supporting proactive ecological management within a vast network of collaborators, and has been endorsed by the international intergovernmental commission of UNESCO as a featured project for the Decade of Ocean Science for Sustainable Development. 

How to cite: Carrière, J. and Dreujou, E.: Enviro-Actions: a preventive management tool designed for industrial port areas of the world, One Ocean Science Congress 2025, Nice, France, 3–6 Jun 2025, OOS2025-854, https://doi.org/10.5194/oos2025-854, 2025.

In September 2024, Italy approved its first National Maritime Spatial Plans (MS Plans). By adopting a multi-scalar approach, coastal regional authorities were empowered to develop proactively their MSP strategy within the broader national framework. Despite this relevant progress, challenges emerged regarding the participation of local stakeholders, sparking the debate about the extent to which this first planning cycle effectively engaged with the actors at the local scale.

To respond to such a challenge, within the REGINA-MSP (Regions to boost National Maritime Spatial Planning) project, we tested a participatory democracy planning process directly engaging regional and local stakeholders in Northern Sardinia to co-design MSP solutions responding to regional and local needs. This area was selected as a case study due the high concentration of marine protected areas, valuable landscape assets and several maritime activities, such as fisheries, aquaculture, tourism, recreational shipping, maritime transport, and port operations.

A bottom-up process allowed to involve a community of over 30 stakeholders, including NGOs, port authorities, coastal guard authorities, associations of fisheries and aquaculture operators, research institutions, natural park authorities, offices of regional and municipal authorities.

The process involved six phases: (i) Preliminary workshops; the spatial provisions and measures identified by the Italian MS Plan concerning the Sardinia Region were presented to the stakeholders in two thematic events, focusing on Gulf of Olbia and on the Gulf of Asinara, and aimed at mapping conflictual and synergistic interactions of relevance at the case-study level. Stakeholders collaboratively worked, confirming and/or providing feedbacks about these interactions and integrating knowledge on the local needs; (ii) First review exchange; through bilateral interviews with the stakeholders, this step further detailed the identified conflicts, synergies and needs, ensuring coherence and further verification; (iii) Drafting targeted solutions; this step identified potential solutions to address the conflicts, support the synergies and respond to the needs; (iv) Informative and preparatory exchange; a preliminary document, including a portfolio of proposed solutions was shared with the stakeholders to set the basis for a conclusive workshop; (v) Conclusive workshop, proposed solutions were presented and discussed with the stakeholders: interactive tools enabled to collect feedback, suggest modifications, explore additional new solutions, and prioritize solutions based on local urgency, readiness and feasibility; (vi) Final validation; the results of the second workshop were used to finalise the portfolio of co-created and scientifically-based solutions, that was eventually shared with all stakeholders.

This participatory process led to the definition of five stakeholder-driven solutions, each responding to a specific local need, that might be incorporated into the next Italian MSP cycle. The co-designed solutions address spatial conflicts (overlapping interests among artisanal fisheries, transport and biodiversity conservation) by promoting a new Particularly Sensitive Sea Area in the Gulf of Asinara, and governance challenges in the Gulf of Olbia, by promoting a permanent technical table between aquaculture farmers and port authorities.

The developed and tested participatory approach can support the co-definition of inclusive planning solutions and offers a replicable model for incorporating local knowledge into multi-level governance frameworks for MSP.

How to cite: Carella, F., Didonna, R., Ramieri, E., Porporato, E., Musco, F., and Brigolin, D.: Stakeholder-Driven MSP in Northern Sardinia: shaping and testing a locally-driven approach to MSP solutions. , One Ocean Science Congress 2025, Nice, France, 3–6 Jun 2025, OOS2025-956, https://doi.org/10.5194/oos2025-956, 2025.

The recent economic development of maritime areas has led to the emergence of new approaches to marine governance in many regions. However, existing governance mechanisms still largely overlook the complex natural and socio-economic processes that characterise marine and coastal ecosystems. This gap explains why the integration of land-sea interactions into marine and coastal governance remains particularly weak and inadequate to address the current challenges, especially in Europe. Despite the introduction of legislation at the European Union level, governance mechanisms remain highly fragmented.
The paper provides an overview of current governance practices in the European Union, including land-sea interactions, particularly since the adoption of Directive 2014/89/EU, which marked a significant turning point in European marine governance. It examines how land-sea interactions are addressed within European marine and coastal governance, identifies the challenges to their effective integration, and proposes a set of policy recommendations to strengthen it. Furthermore, the paper explores the applicability and relevance of European governance frameworks beyond Europe, investigating how these concepts might be adapted or reinterpreted in diverse geographical and socio-political contexts to support strong sustainability in marine and coastal ecosystems.   
Based on the European experience, the paper identifies three key practices for addressing issues related to land-sea interactions: 1) the establishment of a robust legislative framework ; 2) the implementation through an integrated approach between policy sectors, governance levels, and geographical scales ; 3) the development of collaborative governance processes where boundary spanners facilitate communication, coordination and trust between private and public stakeholders. The paper identifies three key action levers to improve the integration of land-sea interactions into European marine and coastal governance : 1) the effective implementation of European legislative frameworks based on integrated approaches; 2) the development of multi-level governance; 3) the establishment of a science-policy-society triangle.

How to cite: Tocco, C., Frehen, L., Forse, A., Ferraro, G., and Failler, P.: Land-sea interactions in European marine governance: State of the art, challenges and recommendations, One Ocean Science Congress 2025, Nice, France, 3–6 Jun 2025, OOS2025-969, https://doi.org/10.5194/oos2025-969, 2025.

The Strait of Otranto, spanning 72 km between Albania and Italy, links the Southern Adriatic and Northern Ionian Seas. Historically, it has been crucial in regulating maritime traffic between the Mediterranean and the Adriatic. Today, it is recognized as an area of high ecological value, hosting diverse marine habitats and species that benefit from multiple layers of protection. These include Marine Protected Areas (MPAs), Natura 2000 and Emerald sites under the European Union and Bern Convention, National Parks, Specially Protected Areas of Mediterranean Importance (SPAMI) under the Barcelona Convention, Ecologically or Biologically Significant Areas (EBSAs) in the South Adriatic and Ionian Sea, and Cetacean Critical Habitats (CCH).

However, the Otranto region faces significant environmental challenges. Its complex and highly diverse ecosystems are under pressure from issues such as coastal erosion, flood risks, and the impact of maritime industries. Deep-sea trawling, marine litter accumulation, urbanization, and tourism further threaten the area's biodiversity and ecological stability. Offshore, deep-sea corals are impacted by trawling, while maritime traffic and fishing activities endanger marine megafauna. Along the Albanian coast, fishing activities pose challenges, compounded by pollution, debris, and overuse of protected areas. Meanwhile, the Italian coast faces threats to Posidonia oceanica meadows from tourism, fisheries, and pollution.

In order to explore options for mitigating risks in the Straight, a Feasibility Study was prepared to assess the potential for establishing Area-Based Management Tools (ABMTs) in the area. This study was carried out as part of the Coastal Area Management Programme (CAMP), under the implementation activities of the Protocol on Integrated Coastal Zone Management (ICZM) to the Barcelona Convention.

The study identified options for Albania and Italy to enhance the protection of existing natural areas and establish new spatial management tools. The first option suggests both countries to use legal frameworks to implement ABMTs within or beyond their territorial seas on a case-by-case basis, as part of a flexible “single complex project area.” This approach supports the 30 x 30 conservation target under both the Kunming-Montreal CBD targets and the Post-2020 Barcelona Convention goals. The second option proposes advancing cooperation by embedding ABMTs within a permanent, adaptable framework, with expanded MPAs, Fisheries Restricted Areas (FRA) under the GFCM, SPAMI sites, and Particularly Sensitive Sea Areas (PSSA) under the IMO among the proposed tools.

Additionally, the study emphasizes Maritime Spatial Planning (MSP) as a means to strengthen cooperative efforts to protect biodiversity in the Strait. In line with an ecosystem-based approach, the study also recommended extending transboundary cooperation to Greece to enhance sustainable management of this shared marine area.

A story-map was developed to share study findings and aid implementation by stakeholders at various levels. The storytelling starts with an area overview, advancing to proposed options. The transboundary, multiscalar scope is visualized with automatic map zooms, while multisectoral activities are depicted through navigable sequence of pictograms, photos, animations and data sliders for protective zoning insights. A cohesive visual style and professional photography are expected to enhance the tool’s cultural and emotional engagement.

How to cite: Bocci, M., Carella, F., Tullio, S., Folco, S., Marina, M., Tea, M., Rezart, K., and Addis, D.: Area-based Management Tools (ABMTs) for cross-border biodiversity and ecosystem protection in the Otranto Strait (Mediterranean Sea), One Ocean Science Congress 2025, Nice, France, 3–6 Jun 2025, OOS2025-1008, https://doi.org/10.5194/oos2025-1008, 2025.

The expansion of marine development projects poses significant challenges in managing competing land uses. For years, land use planning has been a key component of territorial development strategies in Europe and North America. Now, as the complexity of managing maritime spaces increases, a similar approach is needed to integrate all stakeholders and address potential conflicts arising from spatial competition. Fishing businesses face these emerging challenges, highlighting the importance of inclusive and sustainable spatial planning.

A variety of tools can help incorporate stakeholders in these areas, one of which is the vulnerability index. This index combines social and economic factors to evaluate fishers’ vulnerability to spatial modifications resulting from these new maritime uses. The vulnerability is measured through three dimensions: the degree of exposure to risk, the sensitivity of stakeholders to that risk, and their adaptive capacity, which mitigates the first two dimensions.

This study aims to refine and enhance the application of the vulnerability assessment method by examining the capital-based adaptive capacity of fishing enterprises in the context of spatial competition. Through a case study of the fishing industry in Normandy, France, we reveal complex interconnections among physical, natural, human, social, and economic capitals, highlighting the nuanced ways these factors contribute to resilience. This capital-based approach not only enriches the vulnerability index but also offers a more robust framework for inclusive marine spatial planning, to better address the specific needs of fishing communities amidst expanding marine development projects.

How to cite: Buchholzer, H., Le Floc'h, P., Martial, C., and Frésard, M.: Towards Inclusive Marine Spatial Planning: Analysis of Fishing Enterprises' Adaptive Capacity through the Lens of Capital in the Context of Spatial Competition, One Ocean Science Congress 2025, Nice, France, 3–6 Jun 2025, OOS2025-1100, https://doi.org/10.5194/oos2025-1100, 2025.

Effective Marine Spatial Planning (MSP) is essential for the sustainable management of coastal and marine resources, particularly in urbanized areas where multiple human activities overlap. Small-scale fisheries, aquaculture, tourism, and other marine uses share the same space, creating both opportunities and challenges. In that perspective, understanding the spatial distribution of fishing activities (fishing effort and associated catches) is fundamental for effective MSP as it helps identify such interaction patterns and vulnerable fisher communities, and develop targeted marine resource management strategies that can support both resource conservation and fishing livelihoods.

We present a novel approach combining intensive and participatory GPS tracking and catch monitoring to map fishing effort and catches in coral reef ecosystem, with an application in the Bay of Toliara, Madagascar's second-largest reef complex (about 1,000 fishers over 250 km²). Over one year, we tracked fishing trips across several villages, representing 63% of the local fishing fleet, while simultaneously collecting catch data. Mapping results (250 m x 250 m resolution) revealed concerning signs of overexploitation, with annual catches estimated at 4.8t/km² and showing a significant decline of about 50% over the last 30 years. Fishing effort was highly concentrated, with three villages accounting for over 60% of total effort, highlighting limited mobility of the artisanal fleet. While gillnets dominated fishing activities (41% of total fishing effort), we observed spatial segregation among fishing gears, with beach seine and mosquito trawl net use concentrated in shallow areas and handline and speargun used predominantly located in reef and lagoon zones.

Our findings indicate an "overexploitation trap," where fishers are constrained by traditional non-motorized vessels and limited capital and intensify pressure on nearby reef resources rather than accessing distant, less-exploited areas. This pressure on the seascape is exacerbated by the rise in fisher number, the diversification of fishing gear, the emergence of powerful non-selective practices, and the expansion of marine aquaculture and commercial port and tourism activities. The study provides essential baseline data for implementing spatial management measures within the study area, e.g. for protecting juvenile fish habitats in seagrass beds.

This research contributes to SDG 14 targets by providing a cost-effective, participatory, and accurate methodology for mapping small-scale fisheries. The approach generates high-resolution spatial quantitative knowledge relevant for evidence-based management decisions while raising awareness within fishing communities. Our findings also emphasize the urgent need for intervention through marine spatial planning and alternative livelihood development to prevent fishery collapse and ensure sustainable resource use for coastal communities. The study further demonstrates how detailed spatial analysis can inform interactions and competing interests within a coastal seascape, while guiding equitable access to marine resources from different perspectives and supporting conservation objectives.

How to cite: D'Agata, S., Behivoke, F., Guitton, J., Etienne, M.-P., M. Randriatsara, R., Ranaivoson, E., Mahafina, J., and Léopold, M.: Fine-scale distribution of fishing effort and catches highlights opportunities for marine spatial planning in coral reef ecosystems , One Ocean Science Congress 2025, Nice, France, 3–6 Jun 2025, OOS2025-1171, https://doi.org/10.5194/oos2025-1171, 2025.

Climate change and environmental issues are challenging society under several aspects, including spatial planning and governance. In this context, innovative methodologies and tools are emerging as necessary to explore future scenarios, anticipate uncertainties, and support decisions. Particularly at the Land-Sea Interface (LSI), where multiple ecosystems meet and interact, appropriate methodologies are crucial for addressing these complexities.

In this regard, Strategic Foresight Analysis has emerged as a proactive approach to address complex challenges due to its ability to help organizations anticipate and prepare for future issues and opportunities. This study, firstly, explore through a deep literature review the potentials and limitations of Strategic Foresight Analysis for the LSI management; secondly, show an application of this methodology to the Valencian Community, an area particularly vulnerable to climate change impacts.

From the literature review some main advantages of Strategic Foresight Analysis in LSI management emerged. This include its interdisciplinarity and its capacity to facilitate transdisciplinary collaborative exercises. However, there are significant gaps in the applications of this methodology to LSI management, such as the limited use of multiple foresight tools, the complexities related to stakeholder engagement, and the scarcity of science-based approaches, which impacts the global understanding of land-sea dynamics.

The methodological approach applied for the Valencian LSI tries to overcome the identified gaps. On one side, multiple foresight tools (i.e., horizon scanning, megatrend analysis, and scenario planning) are integrated, and on the other side, robust and innovative science-based approaches (i.e., megatrend analysis based on Copernicus climate data, and scenarios based on cumulative impact assessment computed with the help of Generative AI) are implemented. Moreover, stakeholder and expert involvement in the area played a central role, through a questionnaire, an interview, and a workshop, ensuring that the adopted methodologies were aligned with local priorities and challenges.

The results of this Strategic Foresight application include a focus on the region's coastal wetlands, interesting hotspots for the multiple interactions between pressures and natural resources they present. Concerning the megatrend analysis, the results indicate an increase in the median scores of all the climate hazards identified, particularly sea-level rise, coastal erosion, and storm surges. These pressures are most marked in the southern wetlands and in the coast of the Albufera of Valencia. Finally, the results of the scenarios indicate an intensification of cumulative impacts across the different RCPs considered (RCP 4.5 and 8.5) and time horizons (2050 and 2100).

These findings provide a solid foundation for further research and the development of sustainable, adaptive strategies tailored to the specific climate change scenarios and socio-economic needs of these vulnerable coastal regions.

How to cite: Grassi, G., Zennaro, F., Furlan, E., Ferraro, G., Douguet, J.-M., Beunen, R., and Critto, A.: Innovative Strategic Foresight analysis for Land-Sea Management: the Valencian Community case study, One Ocean Science Congress 2025, Nice, France, 3–6 Jun 2025, OOS2025-1212, https://doi.org/10.5194/oos2025-1212, 2025.

How to cite: Sottoriva, S., Menegon, S., Mulazzani, A., Sarretta, A., Abramic, A., Santiago, J. L., Shinoda, D., Kaitaranta, J., Brigolin, D., and Ballesteros, M.: Advancing Ecosystem-Based Practices in Transboundary Contexts: Systematic Comparative Analysis of European MSP Plans , One Ocean Science Congress 2025, Nice, France, 3–6 Jun 2025, OOS2025-1240, https://doi.org/10.5194/oos2025-1240, 2025.

The future of the blue economy will be shaped by humanity’s urgent need for sustainable energy and food, requiring large-scale solutions to meet these challenges. Technological innovations, such as offshore wind energy, are driving ambitious targets, particularly in the North sea, one of Europe’s busiest sea basins. This region is a hub for energy infrastructure, extensive shipping, and fisheries.  However, as energy needs and food demand grow, competition for space in marine environments intensifies, creating uncertainty for both industries and ecosystems. Climate change further complicates these dynamics, with changing water temperatures causing stress to marine habitats, and potential shifts in species ranges. In response to these challenges, the MARine CO-existence (MARCO) scenario-building research project aims to develop tools for strategic planning and marine spatial management. MARCO combines spatial analysis (GIS) and system dynamics to assess temporal changes, providing a transparent framework for stakeholder dialogues and decision-making. This paper outlines the development and application of the fish stock submodel within the MARCO framework, focusing on four ecologically and economically significant species in the North Sea, Norwegian Sea, and Barents Sea. The model evaluates the impacts of fisheries, offshore wind expansion, and climate change on fish populations, with forecasts extending to 2050. Results indicate that while climate change impacts on fish stocks are not expected to be significant until 2050, the cumulative effects of different industries highlight the need for data-driven fisheries management and protection of critical marine areas, including spawning grounds. The model also demonstrates the potential displacement of fisheries and shifts in fishing effort due to the upscaling of offshore wind projects. Finally, it offers valuable insights for balancing industrial development with environmental conservation, supporting food security and sustainable marine resource management in an increasingly crowded and changing ocean.

How to cite: Benjamin, C., Arnesen, B., Pettersen, S. S., Aarnes, Ø., Sanchez, O. R., Pretlove, B., and Hjøllo, S. S.: Marine co-existence between offshore wind and fisheries: insights from fish stock modelling , One Ocean Science Congress 2025, Nice, France, 3–6 Jun 2025, OOS2025-1271, https://doi.org/10.5194/oos2025-1271, 2025.

Over the last 50 years, new ocean economies have emerged and rapidly expanded, driven by declining land-based resources. This has resulted in a complex ocean landscape where diverse and often competing interests intersect among ocean sectors. In particular, offshore oil and gas is an expanding ocean sector that has grown rapidly, sparking considerable opposition due to its potential impacts on other ocean sectors and significant uncertainties regarding its environmental effects. In South Africa, these conflicts are especially pronounced, as the oil and gas industry has expanded despite limited understanding of its impacts on the marine ecosystem. This expansion has faced strong resistance from coastal communities, indigenous groups, and fishers who are concerned about environmental consequences and impacts on other ocean sectors.

This study aims to provide the first comprehensive assessment of the impacts of offshore petroleum extraction on both the marine environment and other critical ocean sectors in South Africa. To understand these impacts in a high-uncertainty, data-poor context, this study employs Bayesian Belief Network (BBN) modeling, a graphical approach that integrates empirical data with expert knowledge. This model enables the evaluation of trade-offs among ocean sectors and serves as a tool for scenario planning related to oil and gas expansion. Additionally, qualitative data from expert interviews will be used to identify key "lock-in" effects— structural or institutional barriers that may prevent pathways towards sustainable blue economy agendas.

By addressing a critical research gap, this study seeks to highlight implications of expanding oil and gas activities on the marine environment, with an emphasis on understanding how oil and gas interacts with other ocean sectors to produce cumulative environmental impacts. This research offers essential socio-ecological insights for future scenario planning and sustainable management in light of expanding blue economies.

How to cite: Lincoln, S., Niiranen, S., Nyström, M., Shannon, L., and Ortega, K.: Navigating Conflicts and Cumulative Impacts: Assessing Offshore Oil and Gas Expansion in South Africa's Marine Environment, One Ocean Science Congress 2025, Nice, France, 3–6 Jun 2025, OOS2025-1370, https://doi.org/10.5194/oos2025-1370, 2025.

This study presents a methodological framework to define socio-economic criteria for prioritizing new Marine Protected Areas (MPAs), boundary adjustments, and network corridors within marine spatial planning (MSP). The framework captures stakeholder perceptions of ecosystem services (ES), including the social, economic, and ecological values that various marine spaces provide.

Through analysis at six European test sites, located in the Atlantic (Azores and Gulf of Cadiz), the Baltic, the North Sea, the Black Sea and the Western Mediterranean; the study identifies and ranks 20 socio-economic criteria, linking these to corresponding ecosystem services.

Findings suggest that MPAs serve essential cultural, regulatory, and provisioning functions, underscoring the need for adaptive management tailored to regional socio-ecological dynamics. This approach highlights the socio-cultural dependence on marine areas, reinforcing MPAs as socio-economic systems that contribute to local livelihoods, recreational opportunities, and biodiversity conservation. The conceptual model visually demonstrates these key MPA functions, showing how adaptive management strategies address varied regional needs. By emphasizing a balanced integration of ES into MSP, the framework offers a structured approach for stakeholders to assess trade-offs and synergies between socio-economic priorities and environmental sustainability.

Grounded in EU policies and international agreements, the methodology supports decision-makers in fostering more sustainable, resilient marine management. The study’s insights advance the understanding of MPAs as dynamic entities, recommending that adaptive management strategies be sensitive to regional needs, thereby enhancing the efficacy and acceptability of marine spatial policies across diverse contexts. All this study was developed under the MSP4Bio Project, a Horizon-funded initiative.

How to cite: García Sanabria, J., Pegorelli, C., De Andres, M., García OnettI, J., and Rayo Luengo, S.: A Socio-Economic Approach to Marine Protected Area Management: a method for Adaptive Spatial Planning, One Ocean Science Congress 2025, Nice, France, 3–6 Jun 2025, OOS2025-1053, https://doi.org/10.5194/oos2025-1053, 2025.

Bridging Conservation and Sustainable Use: Socio-Economic and Governance Criteria for MPA Integration in Marine Spatial Planning

Authors: Camila Pegorelli; Javier García Sanabria, Maria de Andres, Javier Onetti; Liisi Lees, Helena Calado, Debora Gutierrez

This study presents a framework of socio-economic and governance criteria to integrate Marine Protected Areas (MPAs) within Maritime Spatial Planning (MSP), addressing a key gap in aligning conservation with sustainable resource use. MPAs vary in protection levels, from strict reserves to areas allowing multiple uses, which calls for a nuanced management approach within MSP frameworks. This research employs a systematic review and expert consultation to identify twenty socio-economic and twelve governance criteria relevant to both MSP and MPAs, categorized using the IUCN MPA framework: MPA1 (strict environmental protection, minimal or no human activity), MPA2 (ecosystem or natural monument conservation via active management), and MPA3 (multiple uses with a focus on sustainable resource use).

Key findings show that governance criteria (Table 1)—such as stakeholder participation and strategic adaptive management—align MSP effectively with multiple-use MPAs (MPA3), while stricter MPAs (MPA1) exhibit limited socio-economic compatibility with MSP (Table 2), reflecting a divergence in priorities. Conversely, multiple-use MPAs and Other Effective Area-Based Conservation Measures (OECMs) showed moderate to strong positive correlations with MSP objectives, indicating potential for enhanced integration.

Figure 1: Prioritization analysis: value of governance criteria (A) and socio-economic criteria (B) in relation to MSP, MPA and OECMs

Our analysis highlights that MSP processes might benefit from a differentiated approach when engaging with MPAs of varying conservation levels. While MSP can foster ecological connectivity and sustainable development, it must consider MPA-specific socio-economic and governance factors, particularly in areas with stringent conservation restrictions. These findings suggest that MSP effectively can easily find a common path to integrate with multiple-use MPAs and OECMs but may require more attention for stricter MPAs to deliver a more coherent plan and avoid conflicting management goals.

This study contributes to marine policy by establishing a framework that enhances coherence between MSP and MPAs through socio-economic and governance criteria, promoting both conservation and sustainable development, and highlighting points of convergence and divergence between them. This approach aligns with global efforts to achieve the 30x30 biodiversity target, offering practical guidelines for policymakers to balance ecological integrity with sustainable human use in marine areas.

How to cite: Pegorelli, C., Garcia, J., de Andres, M., Garcia-Onetti, J., Lees, L., Gutierrez, D., and Calado, H.: Bridging Conservation and Sustainable Use: Socio-Economic and Governance Criteria for MPA Integration in Marine Spatial Planning, One Ocean Science Congress 2025, Nice, France, 3–6 Jun 2025, OOS2025-1391, https://doi.org/10.5194/oos2025-1391, 2025.

Mohammed A. QURBAN¹*, Lotfi J. RABAOUI¹, Abdulnasser S. AL QUTUB¹, Silvia  AROSSA¹, Afrah ALOTHMAN¹, Eman SABBAGH¹, Carlos GARCIA-SAEZ¹,

¹National Center for Wildlife, Riyadh, Saudi Arabia

* Correspondence: mqurban@ncw.gov.sa   

Seldom is the strong link that exists between Marine Spatial Planning (MSP) and Marine Protected Areas (MPAs) explicitly recognised as is now being done by the National Center for Wildlife (NCW). MSP is the process by which the use of marine space is identified and used to inform development decisions made by regulators. Marine Protected areas that are important for marine conservation are a priority for the NCW. These marine areas are formally designated and have legal protection as MPAs. Where MPAs do not exist in the Saudi Red Sea or the Arabian Gulf, marine plans are of assistance in the identification of areas where they could be sited optimally; taking into account environmental, social, economic and political considerations and existing uses. The Kingdom of Saudi Arabia, has been leading an intensive and extensive effort though the NCW designing and implementing MPAs, and developing a Marine Spatial Planning strategy in both the Arabian Gulf and the Red Sea as part of the Saudi Green Initiative and its 30x30 commitment to contribute to the Kunming-Montreal Global Biodiversity framework, bringing together synergies between Marine Protected Areas and Marine Spatial Planning. Areas such as Farasan Islands Man and Biosphere Reserve and the newly declared Blue Holes and Ras Hatiba in the Red Sea, and the proposed World Heritage site in Gulf of Aqaba and the Northern Red Sea and Jubail and Ras Abu Khamis in the Arabian Gulf are part of these endeavours. MSP includes elements of zoning, with MPAs incorporated as areas where the conservation of biodiversity is a priority. The development of this system of MSP will expand the role and design of individual and networks of MPAs and clarify this role to other user groups and help to reduce conflicts of use and take into account cumulative effects of marine activities to develop a sustainable and resilient-based management of the Kingdom of Saudi Arabia waters.  

How to cite: Garcia-Saez, C. and Arossa, S.: Marine protected areas and marine spatial planning: allocation of resource use and environmental protection for  a sustainable and resilient future., One Ocean Science Congress 2025, Nice, France, 3–6 Jun 2025, OOS2025-588, https://doi.org/10.5194/oos2025-588, 2025.