Shark hotspot: Drivers for distribution and conservation in a tropical oceanic archipelago of the Atlantic Ocean

Introduction: Knowledge on the copulatory behavior and mating ground requirements of large sharks, including the lemon shark, Negaprion brevirostris, is scarce, hampering conservation efforts. Objective: To describe an area in the Equatorial Atlantic used as a mating ground by N. brevirostris, as well as part of the species pre-copulatory behaviors based on citizen reports. Methods: Between 2004 and 2019, recreational divers, dive guides and rangers from the Marine Protected Area (MPA) in Fernando de Noronha Archipelago (FEN) recorded courtship behaviour, females with mating scars, pregnant females, and adult males. Results: N. brevirostris was recorded mating in shallow waters (0.5-2 m deep) during the austral summer (December to March). A specific location in the MPA, Buraco da Raquel lagoon, was the main aggregation and mating site for adult N. brevirostris in FEN. Conclusions: Citizen science records allowed the identification of shallow waters as key sites for the reproduction of this shark in FEN. Results highlight the potential of citizen science contributions to knowledge of sharks in nature and show MPAs as essential for habitat conservation of sharks with decreasing populations along the Brazilian coast, such as N. brevirostris. We present management recommendations to protect N. brevirostris there and elsewhere.

The movement patterns and long-term site-fidelity of primarily juvenile Caribbean reef sharks, Carcharhinus perezi, were investigated using tag-recapture and automated telemetry at an insular nursery area, the Fernando de Noronha Archipelago, Brazil. Of the 143 externally tagged juvenile sharks (<110 cm), 22 (15.3%) were recaptured between 0 and 5 km from the site of tagging after 5–800 days at liberty, suggesting some site-fidelity in young individuals of this species. Site-fidelity and movement patterns of ten juvenile sharks ranging from 78 to 110 cm total length (TL) and one opportunistically captured adult female (224 cm TL) were also investigated for periods of up to 2 years with an array of automated telemetry receivers. Tagging and telemetry data from both inside and outside a marine protected area (MPA) show that shark abundance and activity is greatest along the part of the archipelago’s coastline least disturbed by human activity. Telemetry tracking also showed that juvenile reef sharks demonstrated a high degree of site-fidelity and occupied specific locations along the coast throughout the year, with some evidence of an increase in activity space with ontogeny. Sharks appeared to range more widely at night and there were no seasonal variations in habitat use. Our results suggest that MPAs may be a useful conservation tool to protect young C. perezi and potentially other reef-dwelling carcharhinid sharks during their early life history.

Marine protected areas (MPAs) are important tools for the evaluation of the biodiversity and status of marine systems. However, not all MPAs are equal in their design and management; therefore, it is important to understand how different levels of protection affect the fish communities. In the present study, the shallow reef-area fishes of seven areas in Fernando de Noronha archipelago (north-eastern Brazil) with dissimilar habitat characteristics and different levels of environmental protection (no-take MPA and MPA) were compared. In total, 140 visual censuses were performed, in which 12 958 fishes of 27 families and 50 species were recorded. Differences were recorded between no-take MPAs and MPAs in the benthic composition, abiotic data and fish-community structure and composition. These differences were associated with a higher diversity, richness, density of larger fishes and top target fish families, and biomass per census (nearly 2-fold higher in the no-take MPA). Our findings suggested that the differences in the ichthyofauna were probably more related to the different levels of protection than to dissimilarities in the habitat structure among areas, and that the local no-take MPA (National Marine Park of Fernando de Noronha) is effective in maintaining the shallow reef-area fish communities healthy and diverse.

Industrial accidents, such as toxic spills, have caused catastrophic damage to ecological environments (animals and plants), so that an effective method to assess ecological risks has been demanded. The most recent case: the oil spill that is affecting the Northeast coast of Brazil’s environment. Fernando de Noronha Archipelago (FNA) is a marine protected area off the coast of Brazil. A recent study performed a Quantitative Risk Analysis (QRA) in FNA and the results obtained were that the industrial activity under consideration causes the marine ecosystem of FNA to be endangered, according to the IUCN risk categories. However, this study was conservative and did not assess the fate and transport of the oil in the ocean. In this new study we intend to perform an improved QRA in FNA, including the fate and transport model of the oil, by coupling the Ocean Modeling System – ROMS Regional Oceanic Circulation model with the MEDSLIK-II hydrocarbon dispersion model to simulate the evolution of the oil plume.

Evidence for rapid recovery of shark populations within a coral reef marine protected area

Reef sharks are declining world‐wide under ever‐increasing fishing pressure, with potential consequences on ecosystem functioning. Marine protected areas (MPAs) are currently one of the management tools used to counteract the pervasive impacts of fishing. However, MPAs in which reef sharks are abundant tend to be located in remote and underexploited areas, preventing a fair assessment of management effectiveness beyond remoteness from human activities. Here, we determine the conditions under which MPAs can effectively protect sharks along a wide gradient of reef accessibility, from the vicinity of a regional capital towards remote areas, using 385 records from baited remote underwater video systems and 2,790 underwater visual censuses performed in areas open to fishing and inside 15 MPAs across New Caledonia (South‐Western Pacific). We show that even one of the world's oldest (43 years), largest (172 km2) and most restrictive (no‐entry) MPA (Merlet reserve) on coral reefs has between 17.3% and 45.3% fewer shark species and between 37.2% and 79.8% fewer shark abundance than remote areas in a context where sharks are not historically exploited. On coral reefs situated at less than 1 hr of travel time from humans, shark populations are so low in abundance (less than 0.05 individuals per 1,000 m2) that their functional roles are severely limited. Synthesis and applications. Remote areas are the last sanctuaries for reef sharks, providing a new baseline from which to evaluate human impacts on the species. However, there is no equivalent close to human activities even in large, old and strongly restrictive marine protected areas. As such sharks deserve strong protection efforts. The large, no‐entry marine protected areas, close to humans, offer limited benefits for reef shark populations, but provide more realistic conservation targets for managers of human‐dominated reefs. The exclusion of human activities on a sufficiently large area is key to protect reef shark populations. However, this strategy remains difficult to apply in many countries critically depending on reef resources for food security or livelihood.

Marine Protected Areas (MPAs) in the Tropical Eastern Pacific (TEP) support globally distinct reef fish populations, which exhibit differences between the remote oceanic islands and continental coast. While oceanic island MPAs typically support large abundances of sharks and large predatory teleost (bony) fishes, coastal MPAs show increasing signs of depletion. We deployed stereo-Baited Remote Underwater Video systems (stereo-BRUVs) to assess reef fish community structure across seven MPAs in the region. Oceanic island MPAs had considerably greater species richness and relative abundances than coastal MPAs across all trophic levels. Within the biogeographic subprovinces, fish assemblages were differentiated from each other corresponding to latitude, aligning with the established patterns and supporting finer scale bioregionalization within the TEP. Notably, oceanic MPAs supported some of the largest relative abundances (MaxN hr-1) of sharks on nearshore reefs reported globally. This is likely driven by the regional oceanographic processes enhancing productivity and trophic diversity and sustained by reduced anthropogenic disturbances associated with MPA remoteness and protection. Therefore, we highlight the critical role of MPAs in the TEP as refuges for sharks. However, we also found evidence of fishing pressure on predatory fishes within MPAs across the region. Coastal MPAs in Ecuador exhibit low fish abundances across all trophic levels, with large predators notably absent, indicative of ‘fishing down the food web’. Our results highlight the need for fishing impact assessments and improved conservation measures, such as strengthened enforcement, within MPAs to conserve globally significant marine biodiversity.

The Northeastern Brazil Continental Shelf (NEBCS) is one of the largest shelves off the Brazilian coast, and it is strongly influenced by volcanic and tectonic processes. It can be divided in three portions: Inner shelf (limited by 20 m isobaths), Mid-shelf (from 20 to 40 m depth), and Outer shelf (beyond 40 m depth). Pernambuco is one of the nine States from the Northeast region of Brazil, comprising a coast line of 187 Km (from 07°37.71'S to 08°54.34'S) and an average width of 33.28 Km. The littoral zone is strongly influenced by urban development, with extreme pollution in some areas, particularly near the capital Recife and the metropolitan region. Nevertheless, there are two Marine Protected Area (MPA) included in the Pernambuco EEZ, namely "Fernando de Noronha Archipelago" and "APA Costa dos Corais". However, there have been no habitat mapping studies within this region of the continental shelf, and only a small number along Brazilian coast. Based on the limited information available, the present work aimed to initiate the compilation of existing seafloor data sets on the Pernambuco region. The main objective was to map the physiography and relate it with the classes of sediment, providing a map of the geodiversity from the coast of Pernambuco (from inner to outer shelf). To achieve the objectives of the study, abiotic data available in a public database, and results of technical-scientific surveys from the area were explored. Specifically, topography, slope, and sedimentary texture data were integrated. The topography was based on Gorini (1996). The map curvature was generated on ArcMap 10.1 software. Folks' classes were used to classify the sediment and stations were interpolated by natural neighbor. To improve the information for the locality, data from the Brazilian National Oceanographic Data Bank (BNDO) was added. Thus, a total of 314 samples were accomplished for the analyses. Multidimensional and PCA analyses were conducted using PRIMER 6. Results of bathymetric analysis suggested some considerations: Inner and Outer shelf are narrow in the south and broaden northward along the shelf. On the other hand, the Mid-shelf is a broad southward and narrow at North portion. The slope is variable, being possible to observe several long portions with low degree (0.8-1°) of steepness along the Inner shelf. The presence of steps toward Mid-shelf could be observed as well. A flat portion is registered at the southern part of the shelf. Irregular areas are shown toward North. Pernambuco's platform presents its edge between 55-65 m, revealing an extended stability of the continental shelf, in terms of tectonic and sedimentary processes. The abrupt gradient variation of the shelf edge is clearly marked, as well as the strong steepness on superior slope. Additionally, the MDS and PCA analyses reflect the influence of terrigenous sediment, coming from continental region for the Inner shelf, and the presence of calcareous algae plus organogenic fragments (from beach-rocks and corals) on the mid and outer shelf. The sediment composition is highly relevant to the benthos distribution. Based on our results a texture map was constructed showing the general pattern for the sediment distribution along the shelf of Pernambuco.

Bridging Conservation and Sustainable Use: Socio-Economic and Governance Criteria for MPA Integration in Marine Spatial PlanningAuthors: Camila Pegorelli; Javier García Sanabria, Maria de Andres, Javier Onetti; Liisi Lees, Helena Calado, Debora GutierrezThis 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 A) Prioritization analysis: value of governance criteria in relation to MSP, MPA and OECMs. Color range varies from green (Fully applicable) to red (not relevant or applicable). B) Prioritization Analysis: value of socio-economic criteria in relation to MSP, MPA and OECMs. Color range varies from green (Fully applicable) to red (not relevant or applicable). MPA1 refers to marine protected areas that prioritize strict environmental protection above other uses. MPA2 refers to marine protected areas that prioritize the conservation of ecosystems or natural monuments, which can be achieved through active management. MPA3 refers to marine protected areas of multiple uses where the goal is the sustainable use of natural resources. SD Standard deviation MSP. Maritime Spatial Planning OECMs. Other Effective Conservation Measures 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.

Large, remote marine protected areas (MPAs) containing both reef and pelagic habitats, have been shown to offer considerable refuge to populations of reef‐associated sharks. Many large MPAs are, however, impacted by illegal fishing activity conducted by unlicensed vessels. While enforcement of these reserves is often expensive, it would likely benefit from the integration of ecological data on the mobile animals they are designed to protect. Consequently, shark populations in some protected areas continue to decline, as they remain a prime target for illegal fishers. To understand shark movements and their vulnerability to illegal fishing, 3 years of acoustic tracking data, from 101 reef‐associated sharks, were analysed as movement networks to explore the predictability of movement patterns and identify key movement corridors within the British Indian Ocean Territory (BIOT) MPA. We examined how space use and connectivity overlap with spatially explicit risk of illegal fishing, through data obtained from the management consultancy enforcing the MPA. Using individual‐based models, the movement networks of two sympatric shark species were efficiently predicted with distance‐decay functions (&gt;95% movements accurately predicted). Model outliers were used to highlight the locations with unexpectedly high movement rates where MPA enforcement patrols might most efficiently mitigate predator removal. Activity space estimates and network metrics illustrate that silvertip sharks were more dynamic, less resident and link larger components of the MPA than grey reef sharks. However, we show that this behaviour potentially enhances their exposure to illegal fishing activity. Synthesis and applications. Marine protected area (MPA) enforcement strategies are often limited by resources. The British Indian Ocean Territory MPA, one of the world's largest ‘no take’ MPAs, has a single patrol vessel to enforce 640,000 km2 of open ocean, atoll and reef ecosystems. We argue that to optimize the patrol vessel search strategy and thus enhance their protective capacity, ecological data on the space use and movements of desirable species, such as large‐bodied reef predators, must be incorporated into management plans. Here, we use electronic tracking data to evaluate how shark movement dynamics influence species mortality trajectories in exploited reef ecosystems. In doing so we discuss how network analyses of such data might be applied for protected area enforcement.

Evaluating marine protected areas for the conservation of tropical coastal sharks

Stable isotopes (δ15N) are used to determine trophic level in marine food webs. We assessed if Marine Protected Areas (MPAs) affect trophic level of fishes based on stable isotopes on the Western Mediterranean. A total of 22 studies including 600 observations were found and the final dataset consisted of 11 fish species and 146 observations comparing trophic level inside and outside MPAs. The database was analysed by meta-analysis and the covariate selected was the level of protection (inside vs. outside MPAs). The results indicate significant difference between trophic levels inside and outside MPAs. However, results differ from expectations since the trophic level inside was lower than outside MPAs. Three habitats were analysed (coastal lagoons, demersal and littoral) and significant differences were found among them. Trophic level was higher in demersal habitats than in coastal lagoons and littoral areas. No significant differences were found in species classified by trophic functional groups. We consider several hypotheses explaining the obtained results linked to protection level of the MPAs, time since protection and MPAs size. We debate the suitability of using the stable isotope (δ15N) as direct indicator of trophic level in evaluating MPAs effects on food webs.

Climate change and regional human pressures as challenges for management in oceanic islands, South Atlantic

Efficiency of two contrasted marine protected areas (MPA) in West Africa over a decade of fishing closure

Community and citizen science (CCS), the involvement of non-professional scientists in research and monitoring, has emerged as a key approach in tackling marine conservation issues. This has been evidenced especially in various monitoring efforts of marine protected areas (MPAs) with increasing involvement of CCS programs in contributing data used by MPAs in their adaptive management processes. Having recently engaged in its decadal management review process, this study focuses on the implementation of California’s MPA Network through an examination of the diverse impacts to CCS programs. Through an analysis of survey and interview data provided by leaders representing 12 CCS programs in addition to 13 members of the MPA State Leadership Team, we report on the varied impacts to a diverse set of CCS programs and explore how the relationships between MPAs and CCS in California have evolved over the past 10+ years. We found that regardless of State funding eligibility or receipt to participate in MPA monitoring, all 12 CCS program leaders reported overall increases or growth to their programs across all six focal impact type categories (participants, data, programmatic elements, finances/funding, and staff/partners). Additionally, MPA leaders shared perspectives on the evolving role of CCS, emphasizing the importance of collaboration and data alignment. These findings suggest that continued support for the collaborative MPA-CCS relationships could yield further mutual benefits for both the growing use and utility of CCS and its role in MPA implementation and marine conservation more broadly.