Search Results (167)

Elkhorn coral (Acropora palmata) is a threatened reef-building species that plays a critical role in Caribbean coastal ecosystems. Efficient, large-scale monitoring of A. palmata is essential for evaluating restoration success, yet traditional in situ surveys remain costly and spatially constrained. In this study, we acquired high-resolution (1.8 cm) uncrewed aerial vehicle (UAV) imagery of a coral reef within the United States Virgin Islands’ (USVI) St. Croix East End Marine Park (STXEEMP) and applied deep learning object detection to identify individual A. palmata colonies. We utilized two convolutional neural network architectures, FasterRCNN and MaskRCNN. FasterRCNN was used as an initial screening tool to identify the optimal imagery dataset from several candidates. After identifying the dataset, we used MaskRCNN with an iterative annotation refinement procedure in which initial model predictions were used to augment the training data and achieved an F1 score of 0.78. Detection accuracy was strongly influenced by colony size and apparent water depth, with markedly high accuracy for corals wider than 0.3 m (F1 = 0.87) and located in shallower waters (F1 = 0.81). Beyond detection, MaskRCNN’s polygon outputs enabled the measurement of the individual colony area and the generation of high-resolution coral density maps. These products complement broader-scale prediction and mapping approaches and provide fine-scale, management-relevant information. Although this study was conducted at a single reef site during one acquisition period, the results suggest that UAV-based deep learning workflows offer a promising approach for coral reef monitoring that could support restoration assessments and conservation decision-making, pending validation across additional sites, seasons, and environmental conditions. Full article

This study addresses maritime traffic risks in the Labuan Bajo–Komodo marine tourism corridor, a spatially constrained archipelagic environment characterized by mixed vessel traffic, intensive tourism activity, and high ecological sensitivity. An integrated decision-support framework was developed by combining the Analytic Network Process (ANP) with stakeholder-supported grid-based spatial risk analysis. Expert pairwise comparisons from eight respondents were used to evaluate eight interdependent criteria: Natural Conditions, Navigational Channel, Vessel Factors, Maritime Traffic Conditions, Port Control, Authority/Stakeholders, Tourism, and Environmental Impact. The ANP calculation was conducted using geometric mean group aggregation, consistency ratio assessment, and targeted follow-up clarification for matrices requiring refinement. The final ANP results show that Port Control received the highest priority weight (0.172), followed by Natural Conditions (0.148), Maritime Traffic Conditions (0.144), Environmental Impact (0.135), Vessel Factors (0.121), Navigational Channel (0.120), Authority/Stakeholders (0.104), and Tourism (0.0566). At the global subcriteria level, communication effectiveness, channel complexity, environmental compliance, local traffic density, and seasonal traffic variation emerged as the dominant contributors to risk. A stakeholder-supported partial spatial risk index (SRI) was then calculated for 21 grid cells using spatially mappable ANP criteria. The highest-risk cells were grids 3, 5, 6, 8, 9, 10, and 14, while sensitivity analysis confirmed that grids 3, 5, 6, 9, 10, and 14 remained high risk across all tested spatial-weight scenarios. The findings indicate that maritime traffic risk in Komodo National Park is not driven by environmental exposure alone, but by the interaction of traffic control capacity, natural hazards, traffic concentration, environmental sensitivity, and institutional coordination. The proposed framework supports spatially informed traffic management, environmental compliance, and emergency preparedness planning in marine protected tourism corridors. Full article

Introduction: Marine recreational fishing (MRF) is a socially, economically, and ecologically important activity. However, the absence of systematic monitoring and research in Portugal has limited a comprehensive understanding of the sector and its broader implications. Addressing these gaps is essential to support evidence-based and adaptive recreational fisheries management. Objective: This work aimed to improve understanding of marine recreational fishing in Portugal by integrating social and biological perspectives across national, regional, and local scales. Methodology: A multidisciplinary approach was applied. At the national scale, online questionnaire data were combined with licencing information and regional effort estimates to quantify fishing effort, catches, release rates, catch composition, and direct trip expenditures. The same survey framework was also used to identify recreational fisher profiles based on motivations, behaviours, fishing practices, and attitudes toward management. At the local scale, shore angling surveys conducted before the implementation of the Natural Marine Park of the Algarve Reef were used to estimate fishing activity and establish a baseline for future monitoring. From a biological perspective, field-based catch-and-release experiments were conducted to assess post-release mortality and physiological disturbance, using indicators such as mortality, condition, capture and handling variables, and blood biomarkers of stress and recovery. Results: The national estimates documented substantial fishing effort, catches, and direct expenditure, confirming the relevance of MRF in Portugal at both ecological and socio-economic levels. Portuguese recreational fishers were also shown to be heterogeneous in their motivations, behaviours, and practices, reinforcing the need for management approaches that reflect this diversity. At the local scale, shore angling estimates from the Natural Marine Park of the Algarve Reef provided an important pre-protection baseline for the now established Marine Protected Area, enabling future comparisons and long-term assessment of management effects. Biological experiments showed that recreational fishing can generate measurable physiological disturbance in fish, with post-release condition influenced by capture and handling factors. Among the variables examined, hook location emerged as particularly important, with deep-hooked fish showing greater impairment and higher mortality risk. Conclusions: Together, these findings show that improving recreational fisheries management in Portugal requires integrating social patterns, fishery magnitude, and biological responses to capture and release. Long-term monitoring programmes, combined with management approaches adapted to different fisher profiles and fishing contexts, are essential to support more effective and sustainable recreational fisheries governance. Full article

This study investigated the influence of the National Marine Park of Zakynthos (NMP) on overall tourist satisfaction, with a particular focus on the conservation of the endangered loggerhead sea turtle (Caretta caretta). Using a quantitative methodology on a hybrid sample of 1216 respondents, the research framework was validated via exploratory factor analysis (EFA). The measurement model analyzed visitor attitudes across two primary dimensions: ecological destination factors and institutional management factors. The multiple linear regression analysis indicated that both groups of latent factors contributed significantly to tourist satisfaction (R² = 0.359, p < 0.001). The study revealed high environmental awareness among visitors, who supported spatial–behavioural restrictions and expressed a strong willingness to contribute to protection programs through monetary donations. In conclusion, the results demonstrate that strict biodiversity conservation is not a barrier but rather a critical asset that enhances the destination’s sustainable tourism value. Full article

The development of digital photogrammetry techniques has revolutionized the study of marine ecosystems, enabling the generation of high-precision three-dimensional models from conventional imagery. Structure from Motion (SfM) algorithms have become effective tools for mapping and monitoring underwater habitats, offering a non-invasive and cost-effective alternative to traditional methods. This study presents a pilot methodological validation of SfM-based underwater photogrammetry for the non-invasive morphometric monitoring of vulnerable benthic species, using Pinna rudis. The research focused on refining photogrammetric methodologies for marine conservation, addressing technical challenges such as variations in light conditions, water turbidity, and image acquisition complexity. The study area, the Cabrera Archipelago Maritime-Terrestrial National Park, is a pristine marine environment in the western Mediterranean, hosting diverse benthic communities, including an abundant Pinna rudis population. Data acquisition comprises sampling by scuba diving techniques at depths ranging from 26 to 31 m, performed during the July 2022 field campaign within a permanent demographic plot established in 2013 and the methodology applied involved generating three-dimensional models using SfM, allowing for direct measurements of the seabed and extraction of morphometric parameters of sessile species. The characterization of the Pinna rudis aggregation was based on specimen density and size structure, determined using maximum shell width. The 3D model of the pilot plot covers 86.1 m², hosting 31 individuals. Morphometric measurements derived from SfM-based 3D models were validated against in situ diver measurements of maximum shell width. The results showed that the average maximum width obtained from 3D models (15.19 ± 3.23 cm) was consistent with in situ measurements (15.35 ± 3.48 cm). The mean difference between methods was −0.16 ± 0.82 cm, indicating a negligible systematic bias. The mean absolute error was 0.65 cm, corresponding to an average relative error of 4.34%, and a strong linear relationship was observed between both methods (r = 0.97). These results confirm that underwater photogrammetry is a reliable and non-invasive tool for monitoring vulnerable benthic species, providing high-resolution spatial and morphometric data to support conservation strategies in marine protected areas and allowing the collection of additional data compared to in situ surveys. Full article

The organic complexation of Cu²⁺ in aquatic systems dominates its chemical speciation, affecting its reactivity and bioavailability. Using voltammetry, we investigated Cu²⁺ organic complexing capacity (CuCC) in atmospheric samples, including water-soluble aerosol fraction, rainwater (wet-only deposition), and bulk deposition (wet and dry deposition), collected in a coastal marine area (National Park Brijuni, Adriatic Sea). The focus was on minimizing analytical interferences from surface-active substances (SAS) that accounted for up to 56% of dissolved organic carbon. Method optimization was performed using model SAS (humic-like substances, fulvic acid, and pollen-derived organic material), resulting in an optimal desorption potential of −1.4 V and the addition of 1 mg/L Triton X-100. Under these conditions, CuCC parameters of average ligand concentration and conditional stability constant of (209.8 ± 6.7) nM and log K = (10.2 ± 0.6) in water-soluble aerosol fraction, (117.1 ± 5.0) nM and log K = (9.6 ± 0.2) in rainwater, and (142.9 ± 4.1) nM and log K = (10.2 ± 0.2) in bulk deposition were determined. Atmospheric inputs represented a source of weak Cu-binding ligands for marine areas. In conclusion, short-term monitoring provided insight into the variability of different atmospheric inputs and offered a methodological basis for future long-term, more comprehensive studies. Full article

Ports are complex infrastructure systems operating under adverse marine environments, diverse loading regimes, and significant economic pressures. Among their critical assets are pavement infrastructures that serve multiple functional domains, including container handling and storage areas, internal circulation corridors, passenger–vehicle interfaces, and auxiliary parking zones. However, existing port pavement research remains predominantly concentrated on heavy-duty container applications, while other functional categories are comparatively underexplored. This study develops a structured engineering synthesis of port pavement infrastructure assets by integrating bibliometric mapping, conducted using Scopus-indexed publications, with a functional–structural analysis of worldwide practices. Following the identification of research trends, additional insights from engineering-oriented studies and technical guidance documents were incorporated to strengthen the practical relevance of the investigation. These findings indicate that functional classification should precede structural design decisions, enabling the systematic identification of loading conditions, serviceability requirements, and transition demands across port environments. Heavy-duty operational zones require high-stiffness systems capable of resisting concentrated and repetitive loads, while circulation areas are particularly sensitive to low-speed traffic effects. In contrast, passenger and mixed-use zones necessitate hybrid design strategies that balance structural adequacy with serviceability and long-term durability under marine exposure, whereas auxiliary areas are primarily governed by cost-efficiency and maintenance considerations. The overall research provides a rational basis for investment prioritization, material selection, lifecycle planning, and performance-based pavement management within multifunctional port environments. Full article

The prediction of dynamic responses of offshore wind turbine foundations under wind-wave-current multi-field coupled loads is the cornerstone of safety in offshore wind power engineering. The currently widely adopted equivalent load application method, while computationally efficient, simplifies loads into concentrated forces applied at the pile top and tower top, neglecting fluid-structure dynamic interaction mechanisms, which leads to deviations in response predictions. To overcome this limitation, this paper proposes a high-precision bidirectional fluid-structure interaction numerical framework. The fluid domain employs computational fluid dynamics (CFD) to construct an air-seawater two-phase flow model, utilizing the standard k-ε turbulence model and nonlinear wave theory to accurately simulate complex marine environments. The solid domain establishes a wind turbine-stratified seabed system via the finite element method (FEM), describing soil-rock mechanical properties based on the Mohr-Coulomb constitutive model. Comparative studies indicate that the equivalent static method significantly underestimates the displacement response of pile foundations, particularly under the extreme shutdown conditions examined in this study. This value should be interpreted as a case-specific observation rather than a universal deviation, and the discrepancy may vary with sea state, wind speed, current velocity, and wind–wave misalignment, thereby leading to non-conservative estimates of stress distribution. In contrast, the fluid-structure interaction method can reveal key physical processes such as local flow acceleration and wake–interference effects around the tower and the parked rotor under shutdown conditions, and the nonlinear interaction and resistance-increasing mechanisms between waves and currents. This model provides a reliable tool for safety assessment and damage evolution analysis of wind turbine foundations under extreme marine conditions, promoting the transformation of offshore wind power structure design from empirical formulas to mechanism-driven approaches. Full article

Octopuses of the genus Scaeurgus inhabit upper bathyal benthic habitats and are composed of five recognized species. In this study, we conducted morphological and molecular phylogenetic analyses of two individuals of Scaeurgus and provided additional field observations of the genus in seamounts of the Nazca and Salas y Gómez ridges (southeast Pacific Ocean) over the last six years. Specifically, two specimens of Scaeurgus were collected at 234 m depth in 2019 during the EPIC oceanographic cruise onboard the R/V Mirai (JAMSTEC, Japan), and five other specimens were video recorded at depths between 210 and 340 m during three oceanographic expeditions in 2024 onboard the R/V Falkor (too) (Schmidt Ocean Institute). Both specimens collected during 2019 corresponded to medium-sized females (18 and 38 mm mantle length). Each arm presented 108–132 biserial suckers, nine to ten lamellae per demibranch, and a W-shaped funnel organ. Morphological traits evidenced a closer resemblance of these specimens to S. patagiatus from the NW Pacific; however, phylogenetic evidence did not clearly differentiate them from S. unicirrhus from the Atlantic and the Mediterranean. Although molecular evidence supports the hypothesis of the monophyly of Scaeurgus, further morphological and genetic analysis are needed to delimit and validate the different species proposed along the global distribution of the genus. Full article

Marine reserves are areas where fishing mortality is reduced, and their effectiveness in enhancing fisheries depends on the magnitude of this reduction. We evaluated the effectiveness of two marine reserves in the Mediterranean that differed in enforcement levels using a dual approach that combined interviews with fishers and on-board sampling. Only the reserve with stricter fishing restrictions showed measurable stock enhancement. In areas adjacent to this reserve, catches were higher and body sizes were larger for some species. In addition, fishers adjusted their fishing gear when operating near this reserve, thereby targeting larger individuals. In contrast, no distance-related trends were detected around the reserve with weaker fishing restrictions. Both the interviews and on-board sampling produced consistent results regarding the effectiveness of the two reserves. Full article

Marine ranching has become an important strategy for offshore ecological restoration and fisheries resource conservation in China. In this study, environmental DNA (eDNA) was applied to simultaneously monitor phytoplankton, invertebrates, and fish communities in the Tianjin Dashentang Marine Ranching, the Tianjin Binhai National Marine Park, and the Western Furong Island Marine Ranching Area. eDNA analyses detected more than 190 phytoplankton species, over 340 invertebrate species, and approximately 100 fish species across the three regions. Species richness and community diversity were consistently higher within marine ranching zones than in adjacent control areas, and ranching zones supported a higher proportion of endemic and ecologically important taxa. Redundancy analysis identified temperature, salinity, and pH as the main environmental drivers shaping community composition. Temperature had stronger effects on phytoplankton and invertebrate assemblages in the Dashentang and Furong Island ranches, whereas pH and conductivity were more influential in the Binhai National Marine Park. Temporal comparisons of fish eDNA data from 2021 to 2024 indicated increased alpha diversity, greater representation of key taxa, and higher community stability in 2024. Overall, these results demonstrate the utility of eDNA for integrated biodiversity monitoring and provide scientific support for evaluating and guiding marine ranching development in the Bohai Sea region. Full article

The Veracruz Reef System National Park (VRSNP), located in the central Gulf of Mexico, is one of the country’s most ecologically and economically significant coral systems. Despite its high biodiversity and ecosystem functionality, it is affected by anthropogenic inputs such as fluvial discharges, urban effluents, and port and tourism activities that contribute organic and bacteriological loads. This study aimed to identify the presence of Enterococcus spp. and Vibrio spp. during three climatic seasons—dry, rainy, and north winds—at two water column depths (surface and bottom) across three reefs (Enmedio, Chopas, and Gallega) within the VRSNP during the 2022 annual cycle. Samples were analyzed according to national and international standards. Results showed that Vibrio spp. were influenced mainly by temporal factors, with higher values during north winds and the dry season (>1100 MPN/100 mL); otherwise, rainy conditions reported the lowest load (184.89 ± 15.00 MPN/100 mL). While Enterococcus spp. exhibited greater spatial influence, particularly in surface waters, Enmedio Reef recorded the highest load (478.34 ± 37.28 CFU/100 mL); in addition, Chopas Reef reported the lowest at the bottom (12.43 ± 1.26 CFU/100 mL). The findings highlight the need to strengthen microbiological monitoring protocols in marine coastal ecosystems to assess water quality, public health risks, and the ecological integrity of coral reef environments, as well as the implementation of molecular identification techniques. Full article

This study analyzes the functioning and sustainability of the giant freshwater prawn (Macrobrachium spp.) value chain in the Mangroves Marine Park, Democratic Republic of Congo, using the VCA4D methodology, which integrates economic, social, and environmental dimensions. Data were collected through in-depth interviews, direct observations, and documentary review. The value chain, vital for local communities, also supplies urban markets in Boma, Muanda, Matadi, and Kinshasa. It involves five main actor groups: fishers, middlemen, retailers, restaurateurs, and consumers. High informality, fishers’ dependence on downstream actors, and the lack of traceability and sanitary control compromise overall efficiency and food safety. Value added is predominantly captured by urban retailers, particularly in Kinshasa. Socially and environmentally, the chain exhibits major vulnerabilities, including precarious livelihoods, low female inclusion, limited access to services, and anthropogenic pressures on ecosystems. The study therefore recommends, among other measures, establishing a sustainable management framework, including the protection of breeding areas and regulation of fishing effort, and strengthening actor capacities through improved preservation infrastructure and promotion of transparent pricing mechanisms. These measures aim to enhance the equity, resilience, and sustainability of this critical fishery resource. Full article

Understanding and monitoring benthic habitat distribution is essential for implementing ecosystem-based fisheries management (EBFM). Satellite remote sensing offers a rapid and cost-effective approach to marine habitat assessments; however, its application requires context-specific adjustment to account for environmental variability and differing study aims. As such, predictor variables must be tailored to the specific site and target habitat. This study uses Sentinel-2 Level 2A surface reflectance satellite imagery and stability selection via Random Forest Recursive Feature Elimination to assess the importance of remote sensing indices for mapping moderately deep (<20 m) seagrass habitats in relation to the Marine Stewardship Council-certified Western Australia Enhanced Greenlip Abalone Fishery (WAEGAF). Of the seven indices tested, the Normalised Difference Aquatic Vegetation Index (NDAVI) and Depth Invariant Index for the blue and green bands were selected in the optimal model on every run. The kernelised NDAVI and Water-Adjusted Vegetation Index also scored highly (both 0.92) and were included in the final classification and regression models. Both models performed well and predicted a similar cover and distribution of seagrass within the fishery compared to the surrounding area, providing a baseline and supporting EBFM of the WAEGAF within the surrounding marine protected area. Importantly, the use of indices from freely accessible ready-to-use satellite products via Google Earth Engine workflows and expedited ground truth image annotation using highly accurate (0.96) automatic image annotation provides a rapidly repeatable method for delivering ecosystem information for this fishery. Full article

Unprecedented quantities of pelagic sargassum since 2011 have demanded technical and management responses. Inappropriate measures might worsen environmental impacts, particularly in low-income regions and protected natural areas that also require low-cost, socio-ecologically integrated alternatives. This study aims to evaluate the effectiveness and local perception of sargassum clean-up treatments developed through a community–academic collaboration within a socio-ecological systems framework in the marine protected area Xcalak Reefs National Park (PNAX), at the southernmost Mexican Caribbean coast. In 2019 and 2021, clean-up efforts were implemented through the national PROREST program and a self-organized community group of 35–40 members supported by a multidisciplinary research advisory team. Monitoring in 2021 estimated sargassum removal at 4012 m² over 50–75 work hours. Although average shoreline retreat was obtained (δ_mean = −0.22 m), final accretion of ~0.96 m alleviated community concerns about erosion linked to clean-up activities. The most effective and socially accepted clean-up treatment involved sargassum spreading, collection, drying, and revetment-type beach protection, reducing odors and harmful fauna. However, treatments aimed at shoreline stabilization were impractical, raising doubts about their long-term efficacy. These findings highlight the relevance of integrating ecological performance and social perception in sargassum management, especially where co-management with local communities in marine protected areas is needed. Full article