Operationalizing a fisheries social-ecological system through a Bayesian belief network reveals hotspots for its adaptive capacity in the southern North sea.

Fisheries social-ecological systems (SES) in the North Sea region confront multifaceted challenges stemming from environmental changes, offshore wind farm expansion, and marine protected area establishment. In this paper, we demonstrate the utility of a Bayesian Belief Network (BN) approach in comprehensively capturing and assessing the intricate spatial dynamics within the German plaice-related fisheries SES. The BN integrates ecological, economic, and socio-cultural factors to generate high-resolution maps of profitability and adaptive capacity potential (ACP) as prospective management targets. Our analysis of future scenarios, delineating changes in spatial constraints, economics, and socio-cultural aspects, identifies factors that will exert significant influence on this fisheries SES in the near future. These include the loss of fishing grounds due to the installation of offshore wind farms and marine protected areas, as well as reduced plaice landings due to climate change. The identified ACP hotspots hold the potential to guide the development of localized management strategies and sustainable planning efforts by highlighting the consequences of management decisions. Our findings emphasize the need to consider detailed spatial dynamics of fisheries SES within marine spatial planning (MSP) and illustrate how this information may assist decision-makers and practitioners in area prioritization. We, therefore, propose adopting the concept of fisheries SES within broader integrated management approaches to foster sustainable development of inherently dynamic SES in a rapidly evolving marine environment.

Ecological effects of offshore wind farms on Atlantic cod (Gadus morhua) in the southern North Sea.

Evaluating the ecological effects of the rapid expansion of offshore renewables at local, regional and ecosystem-wide scales is essential to understand the overall socio-ecological trade-offs also for other sectors such as fisheries. Hence, little is known about the ecological impact on demersal fish. To shed light on this topic, we studied the effects of an offshore wind farm in the southern North Sea on different life stages of Atlantic cod (Gadus morhua) using a combination of sampling methods at varying spatial and temporal scales. Our investigations of diet composition and trophic niches indicate that cod utilizes wind turbine piles with scour protection as feeding grounds. Furthermore, collected information on cod adults and early life stages during winter spawning season suggest that spawning activity occurred in winter across the wider wind farm area. We conclude that wind turbine foundations with a scour protection can function as artificial reefs that have local positive effects on the resilience of local cod populations. With our study we contribute to urgently needed observational evidence regarding the ecological impact of offshore wind farm installations to inform area-based management and future monitoring activities.

Evaluation of marine spatial planning requires fit for purpose monitoring strategies.

Marine spatial planning (MSP) has rapidly become the most widely used integrated, place-based management approach in the marine environment. Monitoring and evaluation of MSP is key to inform best practices, adaptive management and plan iteration. While standardised evaluation frameworks cannot be readily applied, accounting for evaluation essentials such as the definition of evaluation objectives, indicators and stakeholder engagement of stakeholders is a prerequisite for meaningful evaluation outcomes. By way of a literature review and eleven practical MSP case studies, we analysed present day trends in evaluation approaches and unravelled the adoption of evaluation essentials for three categories for monitoring and evaluation for plan making, plan outcomes, and policy implementation. We found that at a global scale the focus of MSP evaluation has shifted over the past decade from evaluating predominantly plan outcomes towards the evaluation of plan making. Independent of the scope of the evaluation, evaluation approaches varied greatly from formal and structured processes, building for instance on MSP goals and objectives, to informal processes based on stakeholder interviews. We noted a trend in the adoption of formalised approaches where MSP evaluations have increasingly become linked to MSP policy goals and objectives. However, the enhanced use of MSP objectives and indicators did not result in a more straightforward reporting of outcomes, e.g. such as the achievement of specific MSP objectives. Overall, we found weak linkages between defined MSP objectives, indicators and available monitoring data. While the apparent shift towards a focus on objectives is promising, we highlight the need of fit-for-purpose monitoring data to enable effective evaluation of those objectives. Hence, effective MSP and adaptive management processes require customised and concurrent monitoring and evaluation strategies and procedures. We argue that evaluation processes would also benefit from a better understanding of the general environmental, socio-economic and socio-cultural effects of MSP. Therefore, to understand better environmental effects of MSP, we praise that forthcoming MSP processes need to deepen the understanding and considerations of cause-effect pathways between human activities and changes of ecosystem state through the adoption of targeted cumulative effects assessments.

Socio-ecological vulnerability to tipping points: A review of empirical approaches and their use for marine management.

Sustainability in the provision of ecosystem services requires understanding of the vulnerability of social-ecological systems (SES) to tipping points (TPs). Assessing SES vulnerability to abrupt ecosystem state changes remains challenging, however, because frameworks do not operationally link ecological, socio-economic and cultural elements of the SES. We conducted a targeted literature review on empirical assessments of SES and TPs in the marine realm and their use in ecosystem-based management. Our results revealed a plurality of terminologies, definitions and concepts that hampers practical operationalisation of these concepts. Furthermore, we found a striking lack of socio-cultural aspects in SES vulnerability assessments, possibly because of a lack of involvement of stakeholders and interest groups. We propose guiding principles for assessing vulnerability to TPs that build on participative approaches and prioritise the connectivity between SES components by accounting for component linkages, cascading effects and feedback processes.

A spatial risk approach towards integrated marine spatial planning: A case study on European hake nursery areas in the North Alboran Sea.

Europe's Blue Growth strategy promotes the intensification of human activities at sea and increases the environmental risk such as the decline of the provision of key ecosystem services and potential conflicts among human activities. The fishing sector, in the Alboran Sea, is economically and culturally one of the most important and relies on overexploited target species such as European hake (Merlucius merlucius). Here we identified and quantified the impact of human pressures on the capacity of marine habitats to support the provision of food as an important ecosystem service. We modelled the spatial distribution of nursery areas of European hake in the Alboran Sea, using General Additive Models (GAM) and overlaid those with European Nature Information System (EUNIS) habitats. A sensitivity analysis of hake nursery areas to cumulative human impacts identified the Bay of Malaga as the most sensitive area with trawling frequencies up to 60 times higher than the habitats recovery time. Further, we identified an increased conflict potential among human activities such as trawling and extraction with the presence of Marine Protected Areas (MPAs), which provide MPAs a high vulnerability similar to that found in unprotected areas. Future scenarios considering the increase of renewable energy and alternative food production show conflicts between aquaculture and MPAs as well as offshore wind farms and offshore shipping. Hence, our results show strong arguments for an integrated spatial management approach, including benthic trawling. We also suggest restricting trawling activities inside MPAs to safeguard the habitats capacity to support ecosystem services. Our spatially explicit assessment framework is transparent and transferable to other Mediterranean regions. Thus, it can function as a model on how to incorporate cumulative effect assessments in marine spatial planning processes.

Co-location of passive gear fisheries in offshore wind farms in the German EEZ of the North Sea: A first socio-economic scoping.

Worldwide the renewable energy sector is expanding at sea to address increasing demands. Recently the race for space in heavily used areas such as the North Sea triggered the proposal of co-locating other activities such as aquaculture or fisheries with passive gears in offshore wind farms (OWFs). Our interdisciplinary approach combined a quantification of spatial overlap of activities by using Vessel Monitoring System and logbook data with a stakeholder consultation to conclude and verify on the actual feasibility of co-location. In the German Exclusive Economic Zone (EEZ) of the North Sea up to 90% of Danish and 40% of German annual gillnet fleet landings of plaice overlapped with areas where OWFs are developed. Our results indicated further that the international gillnet fishery could lose up to 50% in landings within the North Sea German EEZ when OWF areas are closed entirely for fisheries. No spatial overlap was found for UK potters targeting brown crab in the German EEZ. We further identified a number of key issues and obstacles that to date hinder an actual implementation of co-location as a measure in the marine spatial planning process: defining the legal base; implementation of safety regulations; delineation of minimum requirements for fishing vessels such as capacities, quotas, technical equipment; implementation of a licensing process; and scoping for financial subsidies to set up business. The stakeholder consultation verified the scientific findings and highlighted that all those points need to be addressed in a planning process. In the German EEZ we have shown that the socio-economic importance of spatial overlap varies within planning boundaries. Therefore we recommend an interdisciplinary bottom-up approach when scoping for suitable areas of co-location. Hence, an informed marine spatial planning process requires comprehensive and spatial explicit socio-economic viability studies factoring in also ecological effects of OWFs on target species.

Assessment of a Bayesian Belief Network-GIS framework as a practical tool to support marine planning.

For the UK continental shelf we developed a Bayesian Belief Network-GIS framework to visualise relationships between cumulative human pressures, sensitive marine landscapes and landscape vulnerability, to assess the consequences of potential marine planning objectives, and to map uncertainty-related changes in management measures. Results revealed that the spatial assessment of footprints and intensities of human activities had more influence on landscape vulnerabilities than the type of landscape sensitivity measure used. We addressed questions regarding consequences of potential planning targets, and necessary management measures with spatially-explicit assessment of their consequences. We conclude that the BN-GIS framework is a practical tool allowing for the visualisation of relationships, the spatial assessment of uncertainty related to spatial management scenarios, the engagement of different stakeholder views, and enables a quick update of new spatial data and relationships. Ultimately, such BN-GIS based tools can support the decision-making process used in adaptive marine management.