Ecosystem-based marine spatial planning is an approach to managing maritime activities while ensuring human well-being and biodiversity conservation as key pillars for sustainable development. Here, we use a comprehensive literature review and a co-development process with experts to build an assessment framework and tool that integrates the fundamental principles of an ecosystem approach to management and translates them into specific actions to be undertaken during planning processes. We illustrate the potential of this tool through the evaluation of two national marine spatial plans (Spain and France), in consultation with the representatives involved in their development and implementation. To ensure more coherent future planning, socio-ecological system evolution in a climate change scenario and the future marine space needs of maritime sectors should be considered, as well as improving the governance structure and knowledge of ecosystem processes. This framework provides a consistent and transparent assessment method for practitioners and competent authorities.

Acoustic methods are routinely used to provide broad scale information on the geographical distribution of benthic marine habitats and sedimentary environments. Although single-frequency multibeam echosounder surveys have dominated seabed characterisation for decades, multifrequency approaches are now gaining favour in order to capture different frequency responses from the same seabed type. The aim of this study is to develop a robust modelling framework for testing the potential application and value of multifrequency (30, 95, and 300 kHz) multibeam backscatter responses to characterize sediments’ grain size in an area with strong geomorphological gradients and benthic ecological variability. We fit a generalized linear model on a multibeam backscatter and its derivatives to examine the explanatory power of single-frequency and multifrequency models with respect to the mean sediment grain size obtained from the grab samples. A strong and statistically significant (p < 0.05) correlation between the mean backscatter and the absolute values of the mean sediment grain size for the data was noted. The root mean squared error (RMSE) values identified the 30 kHz model as the best performing model responsible for explaining the most variation (84.3%) of the mean grain size at a statistically significant output (p < 0.05) with an adjusted r² = 0.82. Overall, the single low-frequency sources showed a marginal gain on the multifrequency model, with the 30 kHz model driving the significance of this multifrequency model, and the inclusion of the higher frequencies diminished the level of agreement. We recommend further detailed and sufficient ground-truth data to better predict sediment properties and to discriminate benthic habitats to enhance the reliability of multifrequency backscatter data for the monitoring and management of marine protected areas.

Community Based Ecotourism (CBET) has the potential to both improve the conservation status of mangrove ecosystems and stimulate local economies. However, these ecotourism initiatives often fail due to a lack of active local participation, poor management and a lack of an appropriate benefit sharing scheme. This paper explores perceptions, opportunities and challenges of community mangrove-based ecotourism in Gazi Bay, Kenya. Data collected from household surveys, key informant interviews and focus group discussions were used to examine local perceptions, challenges and opportunities with respect to their participation in ecotourism as a tool for mangrove conservation. The results obtained indicated that 81.4 % of the Gazi village community was aware of the ecotourism activities being undertaken in the area with 62.8 % acknowledging the socio-economic as well as the environmental impacts of the ecotourism activities. Also, 66.0 % of the local community identified cultural traditions and local skills possessed by the community as having the potential to promote sustainable ecotourism activities in the area. For the design and implementation of any ecotourism venture and the management of mangroves to be sustainable, including that undertaken by the Gazi community, this study recommends prioritising effective local participation and capacity building. In addition, private sector involvement is essential for the mobilisation of resources to further enhance the management and conservation of mangroves in the long-term. The results provide key insights needed not only to improve the design and management of community-led marine conservation initiatives but also for ensuring that optimal conservation benefits are achieved.

Increased human demand on the marine environment and associated biodiversity threatens sustainable delivery of ecosystem goods and services, particularly for shallow shelf-sea habitats. As a result, more attention is being paid to quantifying the geographical range and distribution of seabed habitats and keystone species vulnerable to human pressures. In this study, we develop a workflow based on unsupervised K-Means classification units and Generalized Linear Models built from multi-frequency backscatter analyses (95, 300 kHz), bathymetry and bathymetry derivatives (slope) to predict different levels of sandeel densities in Hempton's Turbot Bank Special Area of Conservation (SAC). For Hyperoplus lanceolatus densities, the performance of single frequency verses multi-frequency models is compared. Relatively high agreement between K-Means clustering outputs (from 95 kHz and multi-frequency models) and ground-truthed sandeel densities is noted. Moreover, Root Mean Squared Error (RMSE) values in this instance demonstrate that single-frequency models are favoured over the multi-frequency model in terms of predictive ability. This is mostly linked to the species strong affinity for sedimentary environments whose variability is better captured by the lower frequency system. Generally, these results provide important information about species-habitat relationships and pinpoint bedform features where sandeels are likely to be found and whose variability is potentially linked to the bathymetry domain. The workflow developed in this study also provides a proof of concept to support the design of a robust species-specific monitoring plan in marine protected areas. Most importantly, we highlight how decisions made during sampling, data handling, analysis could impact the final outputs and interpretation of Species Distribution Models and benthic habitat mapping.

Acoustic methods are frequently used to provide broad-scale information on the spatial extent, range and distribution of marine habitats and sedimentary environments. Although single frequency multibeam echosounders have dominated seabed mapping for decades, multi-frequency approaches are starting to present in the scientific literature. Multibeam survey strategies are generally optimized for the acquisition of bathymetry data, often overlooking the ecological and geological value of backscatter data. This study examines the benefits of combining multi-frequency backscatter responses to discriminate seabed properties in areas with strong geomorphological gradients and associated ecological variability. The frequency-dependence element of backscatter strength is linked to: (i) the dominant scattering regime, (ii) seabed roughness, and (iii) the input of volume scattering related to signal penetration. In 2019, we collected and analyzed multifrequency (200, 95 and 30-kHz) backscatter data from Hempton’s Turbot Bank, a marine protected area off the north coast of Ireland. We compare these data with legacy 300 kHz backscatter data from 2013 to explore the backscatter variability in the context of geomorphological change. We assess the explanatory power of multi-frequency vis-à-vis single-frequency backscatter data in terms of bathymetry, sediment granulometry and infaunal community structure. Results improve our understanding of the link between backscatter properties and geomorphology, with specific recommendations towards minimizing information loss and establishing minimum data requirements for frequency-based benthic habitat discrimination. Improved discrimination of geomorphology and benthic habitat characteristics enhances the reliability of backscatter data as a monitoring technique for area-based protection of marine resources.

As a vital component in marine food webs, sandeels Ammodytes spp. are an important food source for a range of vulnerable birds, mammals and commercial fish species. Sandeels have a very specific sediment composition preference: >15% particles 0.25-2 mm diameter (medium and coarse sand), as demonstrated from research in the North Sea. Policy makers now recognise the necessity to protect not only seabird breeding sites but also their food species and foraging grounds. Using seabed sediment samples and underwater video from the Northern Ireland inshore zone, this study characterised habitat suitable for sandeel in the area. This was compiled with various environmental variables to inform 3 random forest habitat prediction models. Model evaluation and independent data demonstrated that the resultant habitat suitability models showed significant discrimination ability and can identify areas suitable for sandeel habitation. Equipped with this knowledge, policy makers can now target protection of such habitat to enhance conservation of internationally protected seabirds and cetaceans that rely on sandeels for continued breeding success. Further use and development of these techniques is vital in providing policy makers with the tools to formulate management strategies which properly consider and protect forage species, which in turn can provide better breeding success and persistence of threatened and endangered species.