Mediterranean Marine Protected Areas Research Articles

Evaluating the long term effectiveness of a Mediterranean marine protected area to tackle the effects of invasive and range expanding herbivorous fish on rocky reefs

Here we provide evidence, along an 8-year period time-series based on multifaceted data from a Mediterranean marine protected area (MPA), whether protection can tackle invasive and range expanding herbivore fishes, and their effects on the algal resource availability, taking into account the population trends of predatory fishes, fisheries catches of herbivore fishes and sea surface temperature (SST) through time. Our findings pointed out that an ineffective in restoring top-down control process MPA may facilitate, rather than alleviate, the sudden and enduring population burst of invasive and range-expanding herbivorous fishes at tipping points of abrupt change. This subsequently results in the deterioration of rocky reef habitats and the depletion of algal resources, with the tipping points of abrupt change for algal and herbivore fish species not overlapping chronologically. As sea temperature increases, ineffective or recently established MPAs may inadvertently facilitate the proliferation of invasive and range-expanding species, posing a significant challenge to management effectiveness and conservation objectives.

Linking courtship calls and observed behaviours of Epinephelus marginatus in the wild offers new insights into its reproduction and conservation

Abstract Groupers are marine fishes particularly vulnerable to overexploitation owing to their reproduction‐related traits. The dusky grouper Epinephelus marginatus is classified as ‘Endangered’ in the Mediterranean Sea, where protection measures have proven critical for allowing population recovery and persistence of the species. However, knowledge gaps remain regarding its reproductive behaviours and spawning sites. As with other grouper species, the dusky grouper is known to produce courtship‐associated sounds, which were validated in captivity, but no study has ever established a link between sound production and observed behaviours in the wild. This study aims to characterize, both visually and acoustically, the behavioural patterns of wild dusky grouper, thus specifically linking visual courtship behaviours to the associated sound production. Visual as well as passive acoustic methods were employed at two presumptive spawning sites within a Mediterranean Marine Protected Area (MPA) in the north‐western Mediterranean Sea over two consecutive summer seasons (2017 and 2018). The temporal patterns of sound production showed site specificity over the month in which reproductive activity was most intense. Courtship calls were mostly recorded around sunset at both study sites and were significantly associated with visual reproductive behaviours. Results also indicated a temporal partitioning in the acoustic activity of the species, with different sound types being recorded at distinct times of the day, likely corresponding to the occurrence of various behaviours during those periods. These findings have important implications for identifying and monitoring dusky grouper spawning sites using passive acoustic methods, therefore providing valuable information for the development, implementation, and/or enforcement of effective conservation measures therein.

Transforming marine monitoring: Using eDNA metabarcoding to improve the monitoring of the Mediterranean Marine Protected Areas network

The creation of Marine Protected Areas (MPAs) is central to the European Union’s strategy for protecting and restoring marine environments. However, current research indicates that monitoring of MPAs is insufficient to ensure their protective role. In response, the European Commission encourages the development and adoption of more effective monitoring tools for MPAs. Environmental DNA (eDNA) methods may serve this function, but their use in MPA monitoring and management remains relatively unexplored. The current study addresses this gap by examining the potential for eDNA to enhance monitoring within Mediterranean MPAs, where monitoring challenges are especially severe. We addressed the gap by synthesizing the results of two analyses. First, a systematic literature review examined existing applications of eDNA metabarcoding to monitor marine habitats. From the experiences documented in the reviewed literature, we applied a SWOT analysis (a framework used to identify and analyze strengths, weaknesses, opportunities and threats) to assess the tool’s appropriateness for EU monitoring requirements. Second, we probed the tool’s suitability for Mediterranean MPAs with a questionnaire on monitoring and other challenges completed by the managers of 29 MPAs in the region. The findings of our SWOT analysis demonstrated that when compared to conventional monitoring methods, eDNA frequently outperformed them or acted as a crucial supplement. We also found that eDNA is suitable for most criteria set forth in EU requirements. Our questionnaire revealed monitoring strategy limitations that eDNA approaches may alleviate. Still, eDNA approaches do have drawbacks which may jeopardize its accuracy and sufficiency. Incorporating eDNA monitoring methods has great potential to enhance protection efforts in MPAs in the Mediterranean and elsewhere. Their successful adoption will require improved coordination among stakeholders and current, comprehensive, and customized recommendations for MPA managers. This will improve the overall functioning of MPA networks and thus support the role of MPAs in safeguarding vulnerable marine environments.

Recurrent marine heatwaves threaten the resilience and viability of a key Mediterranean octocoral species

Abstract Long‐term ecological studies are essential for understanding the resilience of temperate reefs to ocean warming and the response of their habitat‐forming species to recurrent marine heatwaves (MHWs). This study evaluated the long‐term response (2005–2021) of the habitat‐forming octocoral Eunicella singularis (Esper, 1791) to recurrent MHWs in a Mediterranean marine protected area established more than 25 years ago, where restrictions on fishing and diving activities are well enforced. During the study period, there were two mass‐mortality events (MMEs), in 2007 and 2018, that dramatically disrupted the local gorgonian population. The MMEs were triggered by different temperature dynamics, which ultimately led to differential patterns in mortality rates. The record‐breaking MHW in 2018 prompted one of the largest MMEs ever recorded in the Mediterranean Sea, which affected 75% of the individuals in the gorgonian population and killed 12.5% of colonies. Furthermore, MHWs were detected in all years from 2014 to 2021, preventing injured tissues from fully recovering, leading to significant accumulated damage at the end of the study period (30 times higher than the levels prior to the first MME), and a marked decrease in resilience that threatens the population viability of this long‐lived species. The octocoral studied is one of the most important structural and biomass contributors to one of the most diverse Mediterranean communities. These results underscore the great risk that annual MHWs pose to the long‐term integrity of the circalittoral rocky bottoms of the Mediterranean coasts. In the face of climate change, MPAs must provide areas of reduced anthropic stress for gorgonian populations, enabling the restoration and maintenance of natural processes. Additionally, MPAs should serve as sentinel areas to test the effectiveness of coral restoration actions, which can help managers and scientists to estimate the usefulness of these techniques.

Consistent edge effect patterns revealed using continuous surveys across an Eastern Mediterranean no-take marine protected area

AbstractBecause marine protected areas (MPAs) are not equally effective across their areas, monitoring should progress from dichotomic (within vs. outside) to a finer spatial resolution. Here, we examine the effect of an Eastern Mediterranean no-take MPA on fishes across the MPA and into fished areas, using three methods: underwater visual censuses, acoustic surveys, and towed-diver surveys. The Eastern Mediterranean includes non-indigenous species, so the effect of the MPA was also evaluated for its resistance to invasion. The fine-scale analysis revealed ecological phenomena that could not be captured by dichotomic sampling, such as the edge effect, a reduction of fish biomass along the MPA periphery. Despite their differences, all three methods revealed similar spatial patterns. The fine-scale analysis did not support a biotic resistance of the MPA to non-indigenous species. Our study supports the prevalence of edge effects even in well-enforced no-take MPAs and highlights the need for continuous monitoring to reveal these patterns.

Drivers of Small-Scale Fishers’ Acceptability across Mediterranean Marine Protected Areas at Different Stages of Establishment

The success of marine protected areas (MPAs) in achieving conservation and sustainable development goals hinges on, among other things, their social acceptability by local communities. Small-scale fishing communities represent a key stakeholder category within and around MPAs. Although many authors have examined the social acceptability of MPAs, relatively few studies have addressed this issue by considering how MPA acceptability is built and can be preserved. This study assessed the latent structure of MPA social acceptability and identified the individual and institutional variables driving stakeholders’ acceptability. Using questionnaire surveys, 124 small-scale fishers’ perceptions of MPAs and their social acceptability were explored in six Mediterranean MPAs (three were implemented, and three were designated). The results show that MPA acceptability is positively related to fishers’ age. The findings also highlight that the formal establishment of MPAs is not a sufficient condition for increasing MPA acceptability among fishers. Considerations about the possibility that MPA acceptability can be increased by building support and compliance emerged. MPA managers should implement successful long-term stakeholder engagement initiatives to increase commitment around conservation measures and to improve overall MPA effectiveness.

Mapping microplastic overlap between marine compartments and biodiversity in a Mediterranean marine protected area

The Mediterranean Sea is adversely affected by human activities, of which the release of mismanaged waste into the marine environment, primarily plastic pollution, is one of the most omnipresent. The primary goal of this study is to link microplastic ingestion in several bioindicator species and creating hazard maps from microplastics sampled along the seafloor, in the hyperbenthos and along the sea surface layer in a Marine Protected Area (MPA). Considering the connectivity between these layers, the findings of this study identify areas of concern, especially within bay areas, where marine diversity is exposed to microplastic debris ingestion. In terms of exposure to plastic debris, our findings indicate that areas with high species diversity are particularly vulnerable to plastic exposure. The best model integrated the mean exposure of each species to plastic debris across each layer and the nektobenthic species inhabiting the hyperbenthos layer were found to be the most at risk. Furthermore, the cumulative model's scenario indicated a higher risk to plastic ingestion when all habitats were considered jointly. Overall, the findings of this research highlight marine diversity in a Mediterranean MPA are vulnerable to microplastic pollution, and this study's proposed exposure methodology is applicable to other MPAs.

Hybridizing research and decision-making as a path toward sustainability in marine spaces

Projecting the combined effect of management options and the evolving climate is necessary to inform shared sustainable futures for marine activities and biodiversity. However, engaging multisectoral stakeholders in biodiversity-use scenario analysis remains a challenge. Using a French Mediterranean marine protected area (MPA) as a marine social-ecological case study, we coupled codesigned visioning narratives at horizon 2050 with an ecosystem-based model. Our analysis revealed a mismatch between the stated vision endpoints at 2050 and the model prediction narrative objectives. However, the discussions that arose from the approach opened the way for previously unidentified transformative pathways. Hybridizing research and decision-making with iterative collaborative modeling frameworks can enhance adaptive management policies, leveraging pathways toward sustainability.

Are Mediterranean marine threatened species at high risk by climate change?

Rapid anthropogenic climate change is driving threatened biodiversity one step closer to extinction. Effects on native biodiversity are determined by an interplay between species' exposure to climate change and their specific ecological and life-history characteristics that render them even more susceptible. Impacts on biodiversity have already been reported, however, a systematic risk evaluation of threatened marine populations is lacking. Here, we employ a trait-based approach to assess the risk of 90 threatened marine Mediterranean species to climate change, combining species' exposure to increased sea temperature and intrinsic vulnerability. One-quarter of the threatened marine biodiversity of the Mediterranean Sea is predicted to be under elevated levels of climate risk, with various traits identified as key vulnerability traits. High-risk taxa including sea turtles, marine mammals, Anthozoa and Chondrichthyes are highlighted. Climate risk, vulnerability and exposure hotspots are distributed along the Western Mediterranean, Alboran, Aegean, and Adriatic Seas. At each Mediterranean marine ecoregion, 21%-31% of their threatened species have high climate risk. All Mediterranean marine protected areas host threatened species with high risk to climate change, with 90% having a minimum of 4 up to 19 species of high climate risk, making the objective of a climate-smart conservation strategy a crucial task for immediate planning and action. Our findings aspire to offer new insights for systematic, spatially strategic planning and prioritization of vulnerable marine life in the face of accelerating climate change.

Marine protected areas' positive effect on fish biomass persists across the steep climatic gradient of the Mediterranean Sea

Abstract The positive effect of fully protected marine protected areas (MPAs) on marine biodiversity, and specifically on fishes, has been widely documented. In contrast, the potential of MPAs to mitigate the impact of adverse climatic conditions has seldom been investigated. Here, we assessed the effectiveness of MPAs, quantified as increasing fish biomass, across wide geographic and environmental gradients across the Mediterranean Sea. We performed underwater visual surveys within and outside MPAs to characterize fish assemblages in 52 rocky reef sites across an extent of over 3300 km. We used the steep spatial temperature gradient across the Mediterranean as a ‘space‐for‐time’ substitution to infer climate‐driven temporal changes. We found that, as expected, Mediterranean MPAs increased fish biomass. At the same time, higher seawater temperatures are associated with decreased fish biomass, changes in species composition, and shifts towards more thermophilic species. Importantly, we found that the rate of decrease in fish biomass with temperature was similar between protected and fished sites. Taken together, these results suggest that the capacity of MPAs to harbour higher fish biomass, compared to surrounding areas, is maintained across a broad temperature range. At the same time, MPAs will not be able to offset larger‐scale biotic alterations associated with climate change. Policy implications. Our results suggest that sustained warming will likely reduce fish biomass in the Mediterranean Sea and shift community structure, requiring more conservative targets for fishery regulations. At the same time, protection from fishing will remain an important management tool even with future high‐water temperatures, and MPAs are expected to continue to provide local‐scale benefits to conservation and fisheries.

Assessing the Effect of Full Protection on the Biomass of Ericaria amentacea and Understory Assemblages: Evidence from Two Mediterranean Marine Protected Areas

Cystoseira sensu lato marine forests, which are among the most productive and diverse systems in rocky intertidal and subtidal habitats of the Mediterranean Sea, are experiencing a widespread decline throughout the basin due to increasing human pressures. Yet it is still unclear whether Marine Protected Areas (MPAs) may represent effective tools for conservation of these important habitat formers and their associated assemblages. Here, we compared the biomass of intertidal stands of Ericaria amentacea (C. Agardh) Molinari and Guiry and their understory assemblages between the no-take zone and control sites in two Mediterranean MPAs. We did not find evidence supporting a significant effect of full protection in increasing the biomass of E. amentacea stands and associated assemblages, except for macroalgae of the understory in one of the investigated MPAs, raising concerns on the potential effectiveness of MPAs in mitigating human impacts on these marine forests. Such findings call for major efforts to implement long-term monitoring programs of protected Cystoseira s.l. forests in order to inform an adaptive management of conservation measures within MPAs and eventually to set active interventions of restoration.

Assessing the use of marine protected areas by loggerhead sea turtles (Caretta caretta) tracked from the western Mediterranean

Up to date 264 Marine Protected Areas (MPAs) have been declared in the western Mediterranean Sea. The management plans of 25 of these MPAs include the loggerhead sea turtle (Caretta caretta) as a priority species to protect. However, the actual use of these MPAs by the species remains unknown. Therefore, it is important to assess their contribution to loggerhead conservation in the area. To this end, satellite tracking data of 103 loggerhead turtles of varying sizes and life stages released in Spanish Mediterranean waters and Southern Tyrrhenian Sea over the 2003–2018 period were herein used. Home range and use of MPAs by tracked loggerhead turtles were analysed using post-processed state-space model locations. The tracked turtles visited several Mediterranean MPAs, but barely used them (mean percentage of monitoring time = 12.6 ± 18.2 %). There was very little overlap between turtle’s core areas and tracks with the protected areas. Indeed, most of the core areas and high-density areas estimated (>85 %) were not included within any of the MPAs. Furthermore, less than 5 % of the Mediterranean MPAs were used by any tracked loggerhead sea turtles. Most of these MPAs have no protection measures that focus on this species. Loggerheads mainly use wide oceanic zones and international waters, which are difficult to protect. A high-use core area was identified for loggerhead turtles, located at the western waters of the Algerian Basin, an important fishing area outside any designated MPA and with no protection measures that focus on marine turtle conservation. We conclude that existing MPAs in the western Mediterranean may not contribute enough to loggerhead turtle conservation. We propose potential MPAs designations to be considered for loggerhead sea turtle conservation in the Mediterranean Sea at the Alboran Sea, the Algerian basin, the Northern area of the Strait of Sicily, Northeast Tunisian waters, waters around Malta, waters at the Tyrrhenian Sea and at the Ionian Sea.

Multidecadal monitoring highlighted long-term stability of protected assemblages within a Mediterranean marine reserve

Marine Protected Areas (MPAs) are at the core of management and conservation plans aimed at counteracting the ongoing widespread degradation of marine ecosystems. Although the outcomes of protection in enhancing marine biodiversity and restoring populations of exploited species are widely recognized, the putative effect of MPAs in increasing the resilience of marine communities and ecosystems is still underexplored. In this study, long-term data from a no-take area of a Mediterranean MPA and unprotected locations were used to investigate the effects of full protection on the temporal stability of sessile assemblages on shallow subtidal rocky reefs. Results highlighted that assemblages within the no-take area exhibited a more consistent structure over 20 years of study, whereas a significantly larger temporal variability characterized assemblages at the unprotected locations. Reduced levels of human pressure and stabilizing processes related to the re-establishment of the integrity of trophic networks within the MPA could underlie the observed patterns. Assessing whether MPAs may improve the ability of marine communities to absorb disturbance, from local to large scale sources, is essential to ascertain their contribution to future adaptive conservation strategies in the face of global change. This study provided evidence that MPAs, if well managed, can represent an effective tool to smooth fluctuations in the structure of marine communities, thus potentially reducing their vulnerability to natural and human-driven environmental changes.

Protection effectiveness and sea urchin predation risk: The role of roving predators beyond the boundaries of a marine protected area in the Western Mediterranean Sea

Abstract Effective marine protected areas (MPAs) increase top predator density. Accordingly, a large abundance of predatory fish potentially increases predation risk for sea urchins inside an MPA. Intensity of predation was investigated for the sea urchin Paracentrotus lividus at a Mediterranean MPA. Predation rates were estimated for three levels of protection (full, partial, and absent) and two habitats (rocky reefs and Posidonia oceanica meadows). The natural density of sea urchins was correlated with predator biomass (fish sparids Diplodus spp. and Sparus aurata and the gastropod Hexaplex trunculus), and predation risk was evaluated through a tethering experiment. Significantly higher fish predation was found on the rocky reefs of the fully and non‐protected areas than in the partially protected area. These findings are consistent with the sparid biomass estimated in the fully and partially protected areas. However, a discrepancy between high predation risk and low sparid biomass was detected outside of the MPA's northern boundary, where marine farms (fish and mussels) are present. Benthic predator biomass also increased significantly across the northern boundary, but its predation activity was negligible. The low predatory fish biomass and low sea urchin density suggest a top‐down control by roving predatory fish on the rocky reefs of the non‐protected area, in proximity to the fish farms. Similarly, a significant gradient of benthic predator biomass and low sea urchin density suggest potential predation interactions inside the P. oceanica meadows across the northern MPA boundary near the mussel farms. This study highlights deviations from the expected trophic interactions outside the MPA that could be caused by aquaculture activities. Our understanding of the potential synergies between the MPAs and the nearby human activities needs to be broadened to improve the effectiveness of both ecosystem conservation and resource management.

Reproductive Behaviours and Potentially Associated Sounds of the Mottled Grouper Mycteroperca rubra: Implications for Conservation

Most grouper species worldwide are threatened by overfishing. Effective marine protected areas (MPAs) are known to enable population recovery, and consideration of vulnerable species’ reproductive behaviours is fundamental to monitoring and management plans. Many groupers produce sounds associated with reproductive behaviours. Recording these sounds helps to locate spawning sites and improve management efforts to ensure reproduction and viability. This study focuses on a poorly studied yet likely vulnerable grouper species, Mycteroperca rubra, providing novel insights into its reproductive biology by combining underwater visual census surveys, direct visual observations and passive acoustic monitoring within a Mediterranean MPA during two consecutive summers (2017 and 2018). Results indicate that M. rubra individuals were more abundant and larger at one of the protected study sites, where they also occasionally formed unusual aggregations (<30 individuals), likely for spawning. These aggregations and the observation of courtship behaviours suggest that M. rubra spawns in the surroundings of this study site. Moreover, grouper-like unknown sounds were recorded exclusively at this site, suggesting they are associated with M. rubra courtship behaviours. Therefore, this study provides a basis for validating M. rubra sound production and supports the monitoring of its spawning sites via passive acoustics to improve MPA conservation effectiveness.

The potential benefits of water sports for health and well-being in marine protected areas: a case study in the Mediterranean

ABSTRACT Non-motorized water sports requiring physical efforts such as swimming, scuba diving, kayaking, sailing and surfing are becoming increasingly popular in Mediterranean marine protected areas (MPAs). This research investigates the relationship between these types of water sports and practitioners’ psychological and mental health. It takes the MPAs of Cap de Creus and Gulf of Roses (north-western Mediterranean) as a case study and is underpinned by a literature review and in-depth interviews with specialized water sports instructors. Results provide evidence that doing non-motorized water sports in the sea has positive outcomes for practitioners’ physical and mental health. When done in well-preserved areas, these sports may be a viable tool for both wellness and health recovery, and could be introduced in the community as a preventative and rehabilitation health strategy. This should be accompanied by strategies to address the ecological impacts these sports may have on MPAs.

Performance of a baited underwater video system vs. the underwater visual census technique in assessing the structure of fish assemblages in a Mediterranean marine protected area

Accurate, rapid and cost-effective fish assemblage monitoring is fundamental for marine protected area (MPA) management as a pivotal tool to verify whether and to what extent MPA conservation objectives have been achieved and to redefine these objectives in the framework of an adaptive management. Recently, there has been a sharp increase in the number of video-based methods to study fish fauna, such as baited remote underwater video (BRUV) systems, that, depending on the objectives of the monitoring, can provide complementary or additional data to the more commonly used underwater visual census (UVC). Even though BRUV systems have been widely used in a wide range of geographic contexts and habitats, their use in the Mediterranean basin is still sporadic and the evaluation of the efficiency of BRUV systems and whether they can be used to complement other techniques needs investigation. Thus, the objective of this study was to assess the performance of a BRUV system in a Mediterranean MPA and to evaluate its effectiveness in assessing the structure of fish assemblages (abundance and species richness) by comparing estimates with those obtained by the UVC technique. The fish fauna were monitored by BRUV and UVC in the Capo Caccia – Isola Piana Marine Protected Area (Sardinia, Italy), in July and October-November 2020, at four sampling sites and two areas, hundreds of meters apart, for each site. Overall, 46 taxa and a total of 3620 individuals were observed by BRUV, while 36 taxa and a total of 2995 individuals were observed by UVC. The species first observed in front of the camera’s field of view and able to reach the maximum abundance were the planktivores (Chromis chromis and Oblada melanura) followed by several carnivorous species belonging to the families Labridae, Serranidae and Sparidae, and lastly two carnivores (Mullus surmuletus and Mugilidae spp.) and some high-level predators (Dentex dentex, Seriola dumerili, Sphyraena viridensis, Dicentrarchus labrax). The maximum species richness and abundance were reached between 39 and 50 min. The cumulative species richness increased until around 30 min. Species richness was higher during the BRUV compared to the UVC monitoring. The consistency in findings between BRUV and UVC and a better performance of BRUV in detecting some species (mainly high-level predators), supports BRUV as an additional technique for describing and quantifying species richness and abundance also in the Mediterranean Sea. Based on the results of this study, the advantages/disadvantages, shortcomings, suggestions and resources needed for the two techniques are outlined.

Demo-Genetic Approach for the Conservation and Restoration of a Habitat-Forming Octocoral: The Case of Red Coral, Corallium rubrum, in the Réserve Naturelle de Scandola

Marine protected areas (MPAs) are one of the most efficient conservation tools to buffer marine biodiversity loss induced by human activities. Beside effective enforcement, an accurate understanding of the eco-evolutionary processes underlying the patterns of biodiversity is needed to reap the benefits of management policies. In this context, integrating population genetics with demographic data, the demo-genetic approach, is particularly relevant to shift from a “species-based pattern” toward an “eco-evolutionary-based processes” conservation. Here, targeting a key species in the Mediterranean coralligenous, the red coral, Corallium rubrum, in an emblematic Mediterranean MPA, the “Réserve Naturelle de Scandola” (France), we applied demo-genetic approaches at two contrasted spatial scales, among populations and within one population, to (i) infer the demographic connectivity among populations in the metapopulation network and (ii) shed new light on the genetic connectivity and on the demographic transitions underlying the dynamics of a near-pristine population. Integrating different spatial and temporal scales, we demonstrated (i) an apparent temporal stability in the pattern of genetic diversity and structure in the MPA in spite of a dramatic demographic decline and (ii) contrasted levels of genetic isolation but substantial demographic connectivity among populations. Focusing on the near-pristine population, we complemented the characterization of red coral demographic connectivity suggesting (iii) temporal variability and (iv) the occurrence of collective dispersal. In addition, we demonstrated (v) contrasted patterns of spatial genetic structure (SGS), depending on the considered stage-class (adults vs. juveniles), in the near-pristine population. This last result points out that the overall SGS resulted from a restricted dispersal of locally produced juveniles (SGS among adults and juveniles) combined to mortality during early life stages (decrease of SGS from juveniles to adults). Demonstrating the occurrence of two management units and the importance of two populations (CAVB and ALE) for the network of connectivity, we made recommendations for the management of the Réserve Naturelle de Scandola. Besides, we contributed to the implementation of scientifically driven restoration protocols in red coral by providing estimates for the size, density, and distances among patches of transplanted colonies.

Exploring the convergence of natural flows for the generation of natural capital stocks in marine ecosystems

Marine ecosystems are open, complex, adaptive, and hierarchical systems highly integrated through the exchange of matter and energy flows. This flows exchange allows marine ecosystems to operate at different scales acting as dissipative structures, building natural capital stocks capable of generating several ecosystem services vital for human well-being. Humans derive a wide range of goods and services from marine ecosystems while, at the same time, generate several impacts causing biodiversity loss and seriously affecting their capacity to provide benefits to humans. Effective management strategies are crucial to conserve healthy and diverse marine and coastal ecosystems, maintain the valuable functions and services they provide, and allow for sustainable human activities. In recent years, Marine Protected Areas (MPAs) have been increasingly acknowledged worldwide as important tools to conserve biodiversity and achieve human well-being and sustainable development goals. Assessing the value of natural capital and ecosystem services is crucial to raise awareness on their importance, support conservation strategies, and ensure the sustainable management of marine ecosystems. This study aimed at calculating biomass and emergy-based indicators to assess the value of natural capital stocks in a Mediterranean MPA. The assessment was performed through a biophysical and trophodynamic environmental accounting model fed with field biomass data collected through ad hoc sampling campaigns performed in the MPA. Four main macro-habitats were investigated: sciaphilic hard bottom (coralligenous bioconstructions), photophilic hard bottom, soft bottom, and Posidonia oceanica seagrass beds. The biomass density of the main autotrophic and heterotrophic taxonomic groups identified in the four macro-habitats of the MPA was evaluated. Based on this biomass matrix, the emergy value of natural capital stocks was assessed. The Posidonia oceanica seagrass beds habitat showed the highest biophysical value (2.32·1019 sej) at MPA scale, while coralligenous bioconstructions resulted the habitat with the highest biophysical value per unit area (2.72·1012 sej m−2). In addition, to complement the biophysical assessment with an economic perspective, the emergy-based indicators were converted into monetary units. The total value of natural capital of the whole MPA resulted in about 46 M€. The results of this study can support local managers and policy makers in the development of management strategies to ensure nature conservation and sustainable human activities. They can be also used as a benchmark for the assessment of natural capital value at larger scales in support of a proper consideration and inclusion of nature value into processes of policy making.

Holistic investigation of shore angler profiles to support marine protected areas management

Marine Recreational Fishing (MRF) is growing worldwide in scientific interest, as evidenced by the increasing number of dedicated publications. Studies on the impacts and benefits to socio-ecosystems and mental health are driving this gradual awareness. In the Mediterranean, MRF is currently responsible for 10% of the catches though, in the context of small-scale fisheries decline, it may become dominant. Sustaining this activity represents a universal challenge for the future of mankind. However, the potential influence of anglers' heterogeneity on both the environment and the Catch Per Unit of Effort (CPUE), used internationally to evaluate fish harvest and as a stocks indicator, hinders MRF management. In addition, little data is available on onshore fishing, while the number of practitioners may increase sharply in the context of a socio-economic crisis, especially in marine protected areas (MPA). We conducted a year-round survey in 2017–2018 in a French Mediterranean MPA subject to tourist flows, during which 144 onshore anglers were polled by semi-directive interviews. We used a typology based on technical and socio-economic data of anglers to describe their behaviour diversity and its influence on CPUE and, more broadly, the marine environment in multi-species fisheries. We characterised four onshore angler profiles, segregated in space and time, including one identified as at risk of causing impacts. Our analyses support using total and per species CPUE independently of profiles to evaluate onshore MRF harvest, except for four species. CPUE seem based on the profiles’ skills and self-regulation which induce similar yields between anglers in the absence of control. This demonstrates the importance of taking into account angler behaviour, as each profile could react differently to management actions and highlights that CPUE could be used to detect the effect of changes in regulation in the framework of adaptive management. Our results support that MRF regulations should be simplified and homogenised at the national level and cooperation with fishing shops in MPA co-management should be promoted.