This study explores the propagation characteristics of coastal-trapped waves (CTWs) along the southern Caspian Sea (CS) using in situ observations and a high-resolution Finite-Volume Community Ocean Model (FVCOM). The observations show 2 and 6 days CTWs that begin south of the Absheron Peninsula and travel anticlockwise along the coast. Their phase speed ranges from approximately 0.2–0.6 m/s, with a mean value of about 0.4 m/s derived from multi-event arrival-time analysis. Some events travel more than 400 km, while many weaken on the wide and shallow southeastern shelf. In several cases, the wave amplitude decreases by more than 40 %. Northerly (N), northeasterly (NE), and north-northeasterly (NNE) storms stronger than 10 m/s and longer than 12 h are identified as the primary forcing mechanism, particularly in the western CS. Numerical simulations reproduce the observed CTW patterns and show a mostly barotropic structure in winter. Under thermal stratification, the waves exhibit lower energy and slightly faster phase speeds in the simulated events. These combined results provide a clearer view of how CTWs form, travel, and decay along the southern CS shelf.
{"title":"Propagation characteristics of coastal-trapped waves on the continental shelf of the Caspian Sea","authors":"Ehsan Shad , Ulrich Reza Kamalian , Seyed Mostafa Siadatmousavi , Amirpouya Bakhtiari","doi":"10.1016/j.rsma.2026.104787","DOIUrl":"10.1016/j.rsma.2026.104787","url":null,"abstract":"<div><div>This study explores the propagation characteristics of coastal-trapped waves (CTWs) along the southern Caspian Sea (CS) using in situ observations and a high-resolution Finite-Volume Community Ocean Model (FVCOM). The observations show 2 and 6 days CTWs that begin south of the Absheron Peninsula and travel anticlockwise along the coast. Their phase speed ranges from approximately 0.2–0.6 m/s, with a mean value of about 0.4 m/s derived from multi-event arrival-time analysis. Some events travel more than 400 km, while many weaken on the wide and shallow southeastern shelf. In several cases, the wave amplitude decreases by more than 40 %. Northerly (N), northeasterly (NE), and north-northeasterly (NNE) storms stronger than 10 m/s and longer than 12 h are identified as the primary forcing mechanism, particularly in the western CS. Numerical simulations reproduce the observed CTW patterns and show a mostly barotropic structure in winter. Under thermal stratification, the waves exhibit lower energy and slightly faster phase speeds in the simulated events. These combined results provide a clearer view of how CTWs form, travel, and decay along the southern CS shelf.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"95 ","pages":"Article 104787"},"PeriodicalIF":2.4,"publicationDate":"2026-01-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146191137","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The current study assesses the spatial variability of physicochemical parameters, nutrients, and the distribution of trace metals in surface water and benthic sediments along the offshore Cuddalore region of the Bay of Bengal, India, and evaluates the associated ecological risk. Twenty-five surface water and sediment samples were collected between Cuddalore Harbour and Port Nova, an area impacted by industrial and residential effluents discharged via the Uppanar and Gadilam Rivers. Water analysis revealed a cation abundance order of Na > K > Mg > Ca, with nutrient concentrations ranging from 0.45 to 4.30 mg/l for nitrate and between 0.81 and 2.65 mg/l for phosphate, suggesting localized nutrient enrichment. Ecological risk indices applied to sediments indicated significant contamination: The Contamination Factor (CF) and Enrichment Factor (EF) for Cadmium (Cd) were consistently extreme (EFmean ̴ 65), classifying the sediments as very severely contaminated and underscoring a non-crustal, anthropogenic source. Nickel (Ni) concentrations in the water column were found to be 4–6 times higher than established regional averages for the Bay of Bengal coast, also pointing to specific anthropogenic input. Principal Component Analysis (PCA) confirmed source differentiation: PC1 ( ̴ 34.25 % variance) showed high positive loadings for Fe, Mn, Cr, Cu, Ni, Pb, and Zn indicating a common lithogenic/anthropogenic source strongly controlled by fine-grained sediment texture. Significant positive correlations were observed between key pollutants (Co-Pb >0.80; Ni-Cd = 0.70), further supporting a common industrial origin. The systematic assessment concludes that anthropogenic activities are the main driver of increased trace metal content, posing a significant ecological threat to the coastal ecosystem.
{"title":"Ecological risk assessment and trace metal distribution in surface water and sediments of the Bay of Bengal, India","authors":"Shanmugasundharam Arumugam , Sivakumar Karthikeyan , Ramachandran Annathurai , Saubhagya Ranjan Mahapatra","doi":"10.1016/j.rsma.2026.104789","DOIUrl":"10.1016/j.rsma.2026.104789","url":null,"abstract":"<div><div>The current study assesses the spatial variability of physicochemical parameters, nutrients, and the distribution of trace metals in surface water and benthic sediments along the offshore Cuddalore region of the Bay of Bengal, India, and evaluates the associated ecological risk. Twenty-five surface water and sediment samples were collected between Cuddalore Harbour and Port Nova, an area impacted by industrial and residential effluents discharged via the Uppanar and Gadilam Rivers. Water analysis revealed a cation abundance order of Na > K > Mg > Ca, with nutrient concentrations ranging from 0.45 to 4.30 mg/l for nitrate and between 0.81 and 2.65 mg/l for phosphate, suggesting localized nutrient enrichment. Ecological risk indices applied to sediments indicated significant contamination: The Contamination Factor (CF) and Enrichment Factor (EF) for Cadmium (Cd) were consistently extreme (EF<sub>mean</sub> ̴ 65), classifying the sediments as very severely contaminated and underscoring a non-crustal, anthropogenic source. Nickel (Ni) concentrations in the water column were found to be 4–6 times higher than established regional averages for the Bay of Bengal coast, also pointing to specific anthropogenic input. Principal Component Analysis (PCA) confirmed source differentiation: PC1 ( ̴ 34.25 % variance) showed high positive loadings for Fe, Mn, Cr, Cu, Ni, Pb, and Zn indicating a common lithogenic/anthropogenic source strongly controlled by fine-grained sediment texture. Significant positive correlations were observed between key pollutants (Co-Pb >0.80; Ni-Cd = 0.70), further supporting a common industrial origin. The systematic assessment concludes that anthropogenic activities are the main driver of increased trace metal content, posing a significant ecological threat to the coastal ecosystem.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"95 ","pages":"Article 104789"},"PeriodicalIF":2.4,"publicationDate":"2026-01-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146057414","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-17DOI: 10.1016/j.rsma.2026.104785
Hongchu Yu , Yanxin Han , Lei Xu , Tianming Wei , Xuequan Zhang
Ship offences not only endanger marine resources and ecosystems but also pose severe challenges to joint enforcement among multiple agencies. Recognition and classification of ship offenses are essential for enforcement agencies to respond rapidly. Due to irregular descriptions of ship offense events, conventional methods such as Support Vector Machine (SVM), graph convolutional network (GCN), and random forest (RF) fail to capture complex characteristics. To address this gap, a knowledge-graph–driven and feature-enhanced graph convolutional network (Enhanced KG+GCN) is proposed for the precise classification of ship offenses. It consolidated semantically proximate but differently worded KG entities into unified representations and aligned them with TF-IDF-extracted core domain features, resulting in standardized, non-redundant features better suited to subsequent classification. The judgment documents and official announcements obtained from the Supreme People’s Court and the China Maritime Safety Administration were first standardized and used to construct knowledge graphs for ship offense events. Domain knowledge and relevant regulations were then employed to extract discriminative entities and attributes, which were organized via a hierarchical fusion strategy. The semantic representations of the ship offenses were enriched through the fused entities and attributes. Finally, a semi-supervised GCN was applied to categorize ship offenses, leveraging the feature-enhanced knowledge graph. Experiments demonstrate high precision performance with F1 scores of 0.95 and a mean average precision of 0.97 across five offense categories (illegal fishing, sand mining, dumping, pollution discharge, smuggling), outperforming traditional methods.
{"title":"Incorporating knowledge graph and deep learning method for the classification of ship offense activities","authors":"Hongchu Yu , Yanxin Han , Lei Xu , Tianming Wei , Xuequan Zhang","doi":"10.1016/j.rsma.2026.104785","DOIUrl":"10.1016/j.rsma.2026.104785","url":null,"abstract":"<div><div>Ship offences not only endanger marine resources and ecosystems but also pose severe challenges to joint enforcement among multiple agencies. Recognition and classification of ship offenses are essential for enforcement agencies to respond rapidly. Due to irregular descriptions of ship offense events, conventional methods such as Support Vector Machine (SVM), graph convolutional network (GCN), and random forest (RF) fail to capture complex characteristics. To address this gap, a knowledge-graph–driven and feature-enhanced graph convolutional network (Enhanced KG+GCN) is proposed for the precise classification of ship offenses. It consolidated semantically proximate but differently worded KG entities into unified representations and aligned them with TF-IDF-extracted core domain features, resulting in standardized, non-redundant features better suited to subsequent classification. The judgment documents and official announcements obtained from the Supreme People’s Court and the China Maritime Safety Administration were first standardized and used to construct knowledge graphs for ship offense events. Domain knowledge and relevant regulations were then employed to extract discriminative entities and attributes, which were organized via a hierarchical fusion strategy. The semantic representations of the ship offenses were enriched through the fused entities and attributes. Finally, a semi-supervised GCN was applied to categorize ship offenses, leveraging the feature-enhanced knowledge graph. Experiments demonstrate high precision performance with F1 scores of 0.95 and a mean average precision of 0.97 across five offense categories (illegal fishing, sand mining, dumping, pollution discharge, smuggling), outperforming traditional methods.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"94 ","pages":"Article 104785"},"PeriodicalIF":2.4,"publicationDate":"2026-01-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146038311","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-16DOI: 10.1016/j.rsma.2026.104780
Hyunji Lee , Tongjoo Suh
Marine litter poses severe ecological and societal challenges, yet most research on its management has emphasized technological recycling or engineering approaches. This study investigated marine litter upcycling as a pollution mitigation strategy, focusing on its broader value dimensions and social acceptance. A comprehensive framework encompassing environmental, social, cultural, design, and economic attributes was developed, using a conjoint-based public survey in Seoul and Busan, South Korea. Using rank-ordered logit models, the relative importance of attributes was estimated and the willingness to pay for upcycling initiatives was quantified. Environmental and design-related attributes were consistently the strongest drivers of preference, whereas economic costs exerted a negative effect. Cultural values are particularly salient in coastal regions, reflecting maritime identity, whereas inland residents emphasize environmental, social, cultural, and design aspects, though with less intensity in cultural dimensions, and exhibit greater price sensitivity. Gender and education heterogeneity were also evident: women and highly educated respondents placed greater importance on environmental and design benefits, whereas men attached stronger value to cultural dimensions. Households expressed a clear willingness to provide support for marine litter upcycling initiatives, highlighting its societal legitimacy and potential contribution to marine pollution mitigation. Overall, the results demonstrate the influence of marine litter upcycling in enhancing broader marine litter management efforts and its potential as a sustainable resource innovation driving circular economy transitions. The findings further suggest opportunities for integrating upcycling into broader policy frameworks, as part of regional marine litter action plans and international cooperative initiatives for sustainable coastal governance.
{"title":"Valuation of marine litter upcycling for sustainable resource circulation in Korea","authors":"Hyunji Lee , Tongjoo Suh","doi":"10.1016/j.rsma.2026.104780","DOIUrl":"10.1016/j.rsma.2026.104780","url":null,"abstract":"<div><div>Marine litter poses severe ecological and societal challenges, yet most research on its management has emphasized technological recycling or engineering approaches. This study investigated marine litter upcycling as a pollution mitigation strategy, focusing on its broader value dimensions and social acceptance. A comprehensive framework encompassing environmental, social, cultural, design, and economic attributes was developed, using a conjoint-based public survey in Seoul and Busan, South Korea. Using rank-ordered logit models, the relative importance of attributes was estimated and the willingness to pay for upcycling initiatives was quantified. Environmental and design-related attributes were consistently the strongest drivers of preference, whereas economic costs exerted a negative effect. Cultural values are particularly salient in coastal regions, reflecting maritime identity, whereas inland residents emphasize environmental, social, cultural, and design aspects, though with less intensity in cultural dimensions, and exhibit greater price sensitivity. Gender and education heterogeneity were also evident: women and highly educated respondents placed greater importance on environmental and design benefits, whereas men attached stronger value to cultural dimensions. Households expressed a clear willingness to provide support for marine litter upcycling initiatives, highlighting its societal legitimacy and potential contribution to marine pollution mitigation. Overall, the results demonstrate the influence of marine litter upcycling in enhancing broader marine litter management efforts and its potential as a sustainable resource innovation driving circular economy transitions. The findings further suggest opportunities for integrating upcycling into broader policy frameworks, as part of regional marine litter action plans and international cooperative initiatives for sustainable coastal governance.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"94 ","pages":"Article 104780"},"PeriodicalIF":2.4,"publicationDate":"2026-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146038979","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-16DOI: 10.1016/j.rsma.2026.104772
Bahar Bayhan , Ali Kara , Irmak Kurtul , Mert Minaz , Phillip J. Haubrock , Ali Serhan Tarkan , Cüneyt Kaya
In the Mediterranean, Salema Sarpa salpa is among the most economically important coastal fishes. Yet a major gap in its region-specific, and sex-disaggregated data on biology and growth constraining both precise stock assessments and long ecosystem-based fisheries management strategies in the eastern Mediterranean. To address this data deficiency, this study presents an integrative analysis of the species' biological traits, growth parameters, and population structure in İzmir Bay (eastern Aegean Sea, western Türkiye), using a full annual sampling of 319 individuals. Caught individuals comprised 105 males, 82 females, and 132 hermaphrodites. Total length ranged from 16.7 to 38.0 cm, with the most frequent class lengths being 24.1–27.0 cm (29 %) and 27.1–30.0 cm (25 %). The species exhibited isometric growth (b ≈ 3), indicating that weight increases proportionally with length, while gonadosomatic index trends revealed that spawning occurs mainly in autumn. Among the three tested growth models (von Bertalanffy, Gompertz, Logistic), the von Bertalanffy model provided the best fit for the overall population (L∞ ≈ 46.6 cm, K ≈ 0.08), the Gompertz model for males (L∞ ≈ 35.9 cm, K ≈ 0.20), and the von Bertalanffy again for females and hermaphrodites (L∞ ≈ 38–43 cm). These findings indicate proportional length–weight growth and an autumn spawning period. Analysis of otoliths indicated that age-length relationships followed smooth growth patterns, with female size exceeding males in later age classes. Collected data on Sarpa salpa in İzmir Bay provides valuable baseline data for this species’ regional biology; knowledge crucial to fishery management, stock assessment, and ecological monitoring that may serve as a foundation for sustainable conservation of the Aegean Sea.
{"title":"Growth study of Sarpa salpa in the Aegean Sea using three growth models","authors":"Bahar Bayhan , Ali Kara , Irmak Kurtul , Mert Minaz , Phillip J. Haubrock , Ali Serhan Tarkan , Cüneyt Kaya","doi":"10.1016/j.rsma.2026.104772","DOIUrl":"10.1016/j.rsma.2026.104772","url":null,"abstract":"<div><div>In the Mediterranean, Salema <em>Sarpa salpa</em> is among the most economically important coastal fishes. Yet a major gap in its region-specific, and sex-disaggregated data on biology and growth constraining both precise stock assessments and long ecosystem-based fisheries management strategies in the eastern Mediterranean. To address this data deficiency, this study presents an integrative analysis of the species' biological traits, growth parameters, and population structure in İzmir Bay (eastern Aegean Sea, western Türkiye), using a full annual sampling of 319 individuals. Caught individuals comprised 105 males, 82 females, and 132 hermaphrodites. Total length ranged from 16.7 to 38.0 cm, with the most frequent class lengths being 24.1–27.0 cm (29 %) and 27.1–30.0 cm (25 %). The species exhibited isometric growth (b ≈ 3), indicating that weight increases proportionally with length, while gonadosomatic index trends revealed that spawning occurs mainly in autumn. Among the three tested growth models (von Bertalanffy, Gompertz, Logistic), the von Bertalanffy model provided the best fit for the overall population (L∞ ≈ 46.6 cm, K ≈ 0.08), the Gompertz model for males (L∞ ≈ 35.9 cm, K ≈ 0.20), and the von Bertalanffy again for females and hermaphrodites (L∞ ≈ 38–43 cm). These findings indicate proportional length–weight growth and an autumn spawning period. Analysis of otoliths indicated that age-length relationships followed smooth growth patterns, with female size exceeding males in later age classes. Collected data on <em>Sarpa salpa</em> in İzmir Bay provides valuable baseline data for this species’ regional biology; knowledge crucial to fishery management, stock assessment, and ecological monitoring that may serve as a foundation for sustainable conservation of the Aegean Sea.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"94 ","pages":"Article 104772"},"PeriodicalIF":2.4,"publicationDate":"2026-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145980966","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-16DOI: 10.1016/j.rsma.2026.104783
G.M. Austria-Ortíz , J.E. Sedeño-Díaz , A. Reyes-Márquez , R. Delgado-Macuil , E. López-López
Microplastic pollution is an emerging environmental concern. Microplastics (MPs), in addition to polymers, contain additives, intended to enhance plastic properties. Ecological risk assessments of MPs, usually consider only the polymers. In this study, we advance MPs' risk analysis by incorporating additives into ecological risk indices. Since some additives pose high hazard scores, their inclusion can increase the estimated values of the MPs-induced risk index (H) and the Potential Ecological Risk Index (PERI), thereby providing a more comprehensive and realistic evaluation of MPs' ecological risks. The Tampamachoco Estuarine-Lagoon System (Gulf of Mexico) faces multiple human-related stressors that contribute to plastic pollution. We evaluated the abundance, spatial distribution, and ecological risk indices of MPs in surface water, mid-water, sediment, and oysters (farmed and wild) during dry and rainy seasons. MPs and additives were extracted: from water by direct filtration; from sediments using ZnCl2 (density suspension ρ ≈ 1.6 g/cm³) and filtration; and from oyster tissue by H2O2 digestion and filtration. We used µFTIR analysis to identify the polymers and additives. The average MP concentration was oysters > sediment > mid-water > surface water in both seasons. In oysters, MP load was higher in the dry season (4.73 ± 1.08 MPs/gww) than in the rainy season (1.22 ± 0.31 MPs/gww) (p < 0.05). Eleven kinds of plastic were identified, including additives. The Pollution Load Index (PLI) across all seasons and matrices indicated a minor risk (<10). In contrast, the H index revealed extreme danger risks (>1000), while PERI ranged from minor to medium (oysters), high (sediment), to extreme danger (surface and mid-water).
{"title":"Potential ecological risk from microplastics and additives in the environment and mangrove-associated oysters: The case of a Ramsar coastal lagoon in the Gulf of Mexico","authors":"G.M. Austria-Ortíz , J.E. Sedeño-Díaz , A. Reyes-Márquez , R. Delgado-Macuil , E. López-López","doi":"10.1016/j.rsma.2026.104783","DOIUrl":"10.1016/j.rsma.2026.104783","url":null,"abstract":"<div><div>Microplastic pollution is an emerging environmental concern. Microplastics (MPs), in addition to polymers, contain additives, intended to enhance plastic properties. Ecological risk assessments of MPs, usually consider only the polymers. In this study, we advance MPs' risk analysis by incorporating additives into ecological risk indices. Since some additives pose high hazard scores, their inclusion can increase the estimated values of the MPs-induced risk index (H) and the Potential Ecological Risk Index (PERI), thereby providing a more comprehensive and realistic evaluation of MPs' ecological risks. The Tampamachoco Estuarine-Lagoon System (Gulf of Mexico) faces multiple human-related stressors that contribute to plastic pollution. We evaluated the abundance, spatial distribution, and ecological risk indices of MPs in surface water, mid-water, sediment, and oysters (farmed and wild) during dry and rainy seasons. MPs and additives were extracted: from water by direct filtration; from sediments using ZnCl<sub>2</sub> (density suspension ρ ≈ 1.6 g/cm³) and filtration; and from oyster tissue by H<sub>2</sub>O<sub>2</sub> digestion and filtration. We used µFTIR analysis to identify the polymers and additives. The average MP concentration was oysters > sediment > mid-water > surface water in both seasons. In oysters, MP load was higher in the dry season (4.73 ± 1.08 MPs/gww) than in the rainy season (1.22 ± 0.31 MPs/gww) (p < 0.05). Eleven kinds of plastic were identified, including additives. The Pollution Load Index (PLI) across all seasons and matrices indicated a minor risk (<10). In contrast, the H index revealed extreme danger risks (>1000), while PERI ranged from minor to medium (oysters), high (sediment), to extreme danger (surface and mid-water).</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"94 ","pages":"Article 104783"},"PeriodicalIF":2.4,"publicationDate":"2026-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145980968","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-16DOI: 10.1016/j.rsma.2026.104784
Quesie T. Omnos , Wella T. Tatil , Mudjekeewis D. Santos , Rizal Jhunn F. Robles , Khadiza H. Imlan , Mohammad-Norodom H. Ajik , Ivane R. Pedrosa-Gerasmio
Horseshoe crabs, ancient aquatic arthropods with ecological and medicinal importance, remain understudied in Tawi-Tawi, Philippines. Despite community observations, no formal records exist for Tawi-Tawi, limiting regional conservation planning. This study examined the local ecological knowledge of coastal people regarding horseshoe crabs in Tawi-Tawi to identify their distribution, use, and population trends, providing a baseline for conservation. Data were recorded from semi-structured interviews and analyzed descriptively. A total of 142 respondents provided detailed insights into the local distribution, habitats, population trends, perceptions, and consumption of horseshoe crabs in their areas. The locals identified two distinct species of horseshoe crabs, with features resembling those of Tachypleus tridentatus and Carcinoscorpius rotundicauda. A live specimen of the latter was also verified during the visit. Most respondents perceived a population decline attributed to human impacts and environmental changes. Horseshoe crabs are commonly captured only by hand (93 %), with uses in traditional medicine and rituals. This study provides the first scientific evidence of horseshoe crab presence in Tawi-Tawi. The findings lay the groundwork for strategic management and emphasize the urgent need for effective conservation.
{"title":"Coastal people’s local ecological knowledge on horseshoe crabs from Tawi-Tawi, Philippines: Implications for conservation","authors":"Quesie T. Omnos , Wella T. Tatil , Mudjekeewis D. Santos , Rizal Jhunn F. Robles , Khadiza H. Imlan , Mohammad-Norodom H. Ajik , Ivane R. Pedrosa-Gerasmio","doi":"10.1016/j.rsma.2026.104784","DOIUrl":"10.1016/j.rsma.2026.104784","url":null,"abstract":"<div><div>Horseshoe crabs, ancient aquatic arthropods with ecological and medicinal importance, remain understudied in Tawi-Tawi, Philippines. Despite community observations, no formal records exist for Tawi-Tawi, limiting regional conservation planning. This study examined the local ecological knowledge of coastal people regarding horseshoe crabs in Tawi-Tawi to identify their distribution, use, and population trends, providing a baseline for conservation. Data were recorded from semi-structured interviews and analyzed descriptively. A total of 142 respondents provided detailed insights into the local distribution, habitats, population trends, perceptions, and consumption of horseshoe crabs in their areas. The locals identified two distinct species of horseshoe crabs, with features resembling those of <em>Tachypleus tridentatus</em> and <em>Carcinoscorpius rotundicauda</em>. A live specimen of the latter was also verified during the visit. Most respondents perceived a population decline attributed to human impacts and environmental changes. Horseshoe crabs are commonly captured only by hand (93 %), with uses in traditional medicine and rituals. This study provides the first scientific evidence of horseshoe crab presence in Tawi-Tawi. The findings lay the groundwork for strategic management and emphasize the urgent need for effective conservation.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"94 ","pages":"Article 104784"},"PeriodicalIF":2.4,"publicationDate":"2026-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146038978","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-15DOI: 10.1016/j.rsma.2026.104782
Kiran Jalem , Sagar Kumar Swain , Debdas Mandal
Shoreline retreat poses a significant threat to coastal systems, that are highly vulnerable to climatic and hydrodynamic variability. However, long-term studies linking past changes with future shoreline projections are still limited in many deltaic regions. This study evaluates the spatio-temporal shoreline dynamics of Mousuni Island, West Bengal, over the past four decades (1980–2023) using multi-temporal Landsat imagery and DSAS-based coastal vulnerability assessment framework (DSAS 5.0). Shoreline dynamics were analysed along 1541 transects using five indicators, such as End Point Rate (EPR), Linear Regression Rate (LRR), Weighted Linear Regression (WLR), Net Shoreline Movement (NSM), and Shoreline Change Envelope (SCE). The analysis revealed erosion as the dominant process, affecting nearly 90 % of the island’s perimeter. The mean shoreline retreat was −4.36 m/yr, with extreme erosion rates reaching −23.55 m/yr in the southern and northwestern high-risk zones, whereas limited accretion occurred in northeastern pockets, with a maximum gain of + 2.81 m/yr. Between 1980 and 2023, Mousuni Island lost approximately 19.3 % of its land area, with peak erosion (2.28 km²) during 1990–2000. Forecasting using Kalman Filter model projects further shoreline retreat of 500–700 m by 2043, reinforcing the island’s high vulnerability under sediment deficit, cyclonic pressure, and declining vegetation buffers. The model provides robust estimates, though these include uncertainty related to data resolution and natural variability. Model validation confirmed WLR as the most reliable metric for long-term shoreline prediction. The study’s novelty lies in integrating historical erosion patterns with future risk projections, providing a replicable framework for deltaic island vulnerability assessment. These findings offer valuable insights for nature-based solutions, strategic embankment design, and the development of climate-resilient coastal management frameworks.
{"title":"Spatio-temporal assessment of shoreline retreat and future vulnerability of Mousuni Island, West Bengal, India","authors":"Kiran Jalem , Sagar Kumar Swain , Debdas Mandal","doi":"10.1016/j.rsma.2026.104782","DOIUrl":"10.1016/j.rsma.2026.104782","url":null,"abstract":"<div><div>Shoreline retreat poses a significant threat to coastal systems, that are highly vulnerable to climatic and hydrodynamic variability. However, long-term studies linking past changes with future shoreline projections are still limited in many deltaic regions. This study evaluates the spatio-temporal shoreline dynamics of Mousuni Island, West Bengal, over the past four decades (1980–2023) using multi-temporal Landsat imagery and DSAS-based coastal vulnerability assessment framework (DSAS 5.0). Shoreline dynamics were analysed along 1541 transects using five indicators, such as End Point Rate (EPR), Linear Regression Rate (LRR), Weighted Linear Regression (WLR), Net Shoreline Movement (NSM), and Shoreline Change Envelope (SCE). The analysis revealed erosion as the dominant process, affecting nearly 90 % of the island’s perimeter. The mean shoreline retreat was −4.36 m/yr, with extreme erosion rates reaching −23.55 m/yr in the southern and northwestern high-risk zones, whereas limited accretion occurred in northeastern pockets, with a maximum gain of + 2.81 m/yr. Between 1980 and 2023, Mousuni Island lost approximately 19.3 % of its land area, with peak erosion (2.28 km²) during 1990–2000. Forecasting using Kalman Filter model projects further shoreline retreat of 500–700 m by 2043, reinforcing the island’s high vulnerability under sediment deficit, cyclonic pressure, and declining vegetation buffers. The model provides robust estimates, though these include uncertainty related to data resolution and natural variability. Model validation confirmed WLR as the most reliable metric for long-term shoreline prediction. The study’s novelty lies in integrating historical erosion patterns with future risk projections, providing a replicable framework for deltaic island vulnerability assessment. These findings offer valuable insights for nature-based solutions, strategic embankment design, and the development of climate-resilient coastal management frameworks.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"94 ","pages":"Article 104782"},"PeriodicalIF":2.4,"publicationDate":"2026-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145981065","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-15DOI: 10.1016/j.rsma.2026.104774
Arabe Khan , Md Mahmudul Hasan Rakib , Irteja Hasan , Fairuj Islam , Devlina Saha Aishee , Arafat Islam Pranto , Zitu Kundu , Raian Islam Evan , Rahat Khan , Dhiman Kumer Roy
Disaster vulnerability primarily due to riverbank erosion is one of the most critical concerns of coastal communities living alongside the riverbanks. This study aims to develop the Disaster Vulnerability Index (DVI) by adopting a geometric mean approach to comprehensively assess community vulnerability to riverbank erosion. The DVI is mainly composed of four contributory factors: hazard, exposure, sensitivity, and resilience. These factors are integrated to provide a more nuanced understanding of vulnerability and identify the most influential indicators for evaluating vulnerability. The research was conducted in Manpura Upazila, a highly vulnerable riverine island in Bangladesh, and assessed the vulnerability across its four unions (Dakkhin Sakuchia, Hazirhat, Monpura, and Uttar Sakuchia). The results indicate significant spatial variation in DVI values, highlighting Dakkhin Sakuchia as the most vulnerable union (0.554), followed by Hazirhat (0.499), Monpura (0.470), and Uttar Sakuchia (0.311). It is generally the localized exposure and hazard factors combined with differentiated social and economic sensitivity that influence household resilience capacity and livelihood sustainability, which generally explains this variation in disaster vulnerability. The predominant factors driving higher vulnerability include frequent erosion events, proximity of settlements to riverbanks, significant agricultural losses, and insufficient healthcare, education, and disaster preparedness. The newly developed DVI employs the geometric mean approach to effectively capture the multiplicative interactions among indicators, providing a nuanced, context-sensitive measure of vulnerability. So, this study offers policymakers and disaster management authorities a robust tool to prioritize targeted interventions and allocate resources effectively, aiming to mitigate risks and enhance resilience against riverbank erosion in vulnerable communities.
{"title":"Developing a geometric mean-based disaster vulnerability index (DVI): A holistic approach for quantifying multiplicative vulnerability to riverbank erosion in coastal Bangladesh","authors":"Arabe Khan , Md Mahmudul Hasan Rakib , Irteja Hasan , Fairuj Islam , Devlina Saha Aishee , Arafat Islam Pranto , Zitu Kundu , Raian Islam Evan , Rahat Khan , Dhiman Kumer Roy","doi":"10.1016/j.rsma.2026.104774","DOIUrl":"10.1016/j.rsma.2026.104774","url":null,"abstract":"<div><div>Disaster vulnerability primarily due to riverbank erosion is one of the most critical concerns of coastal communities living alongside the riverbanks. This study aims to develop the Disaster Vulnerability Index (DVI) by adopting a geometric mean approach to comprehensively assess community vulnerability to riverbank erosion. The DVI is mainly composed of four contributory factors: hazard, exposure, sensitivity, and resilience. These factors are integrated to provide a more nuanced understanding of vulnerability and identify the most influential indicators for evaluating vulnerability. The research was conducted in Manpura Upazila, a highly vulnerable riverine island in Bangladesh, and assessed the vulnerability across its four unions (Dakkhin Sakuchia, Hazirhat, Monpura, and Uttar Sakuchia). The results indicate significant spatial variation in DVI values, highlighting Dakkhin Sakuchia as the most vulnerable union (0.554), followed by Hazirhat (0.499), Monpura (0.470), and Uttar Sakuchia (0.311). It is generally the localized exposure and hazard factors combined with differentiated social and economic sensitivity that influence household resilience capacity and livelihood sustainability, which generally explains this variation in disaster vulnerability. The predominant factors driving higher vulnerability include frequent erosion events, proximity of settlements to riverbanks, significant agricultural losses, and insufficient healthcare, education, and disaster preparedness. The newly developed DVI employs the geometric mean approach to effectively capture the multiplicative interactions among indicators, providing a nuanced, context-sensitive measure of vulnerability. So, this study offers policymakers and disaster management authorities a robust tool to prioritize targeted interventions and allocate resources effectively, aiming to mitigate risks and enhance resilience against riverbank erosion in vulnerable communities.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"94 ","pages":"Article 104774"},"PeriodicalIF":2.4,"publicationDate":"2026-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145981066","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-15DOI: 10.1016/j.rsma.2026.104777
Airam Guerra-Marrero , Ana Espino-Ruano , David Jiménez-Alvarado , Lorena Couce-Montero , José J. Castro
The jaguar round crab, Xantho poressa, is the most important bait shellfish species in the Canary Islands. The aim of the study was to assess the status and population structure of Xantho poressa in the island of Gran Canaria. Specimens of X. poressa were caught monthly between July 2020 and December 2021 in three intertidal areas with different fishing pressure. Males were consistently larger and heavier than females, and the sex ratio was not different to 1:1. Length-weight relationship showed a negative allometric growth pattern in both sexes, and no significant differences were found between the sampling areas on three sides of the island, suggesting the presence of a single population. Ovigerous females were observed throughout the year, with a peak between June and August, indicating a continuous reproductive cycle. The ELEFAN method estimated an asymptotic carapace length of 31.19 mm. Catch per unit effort showed notable differences between the sampled areas, being the highest abundances (10.42 g/m2/gatherer) recorded at the northern coast and the lowest (5.10 g/m2/gatherer) at the southern one. The relative low abundance, particularly in the south coast, in relation with the current allowed catch quotas (1500 g/day/gatherer for artisanal fishing, 200 g/day/gatherer for recreational fishing) and a high number of recreational fishing licenses, indicate that the jaguar round crab stock of the island could be in risk of overfishing. This analysis provided crucial biological information to support management and conservation strategies for X. poressa.
{"title":"Population dynamics and life history traits of the commercially important jaguar round crab Xantho poressa (Olivi, 1792) in Gran Canaria’s Intertidal Zones (Spain)","authors":"Airam Guerra-Marrero , Ana Espino-Ruano , David Jiménez-Alvarado , Lorena Couce-Montero , José J. Castro","doi":"10.1016/j.rsma.2026.104777","DOIUrl":"10.1016/j.rsma.2026.104777","url":null,"abstract":"<div><div>The jaguar round crab, <em>Xantho poressa,</em> is the most important bait shellfish species in the Canary Islands. The aim of the study was to assess the status and population structure of <em>Xantho poressa</em> in the island of Gran Canaria. Specimens of <em>X. poressa</em> were caught monthly between July 2020 and December 2021 in three intertidal areas with different fishing pressure. Males were consistently larger and heavier than females, and the sex ratio was not different to 1:1. Length-weight relationship showed a negative allometric growth pattern in both sexes, and no significant differences were found between the sampling areas on three sides of the island, suggesting the presence of a single population. Ovigerous females were observed throughout the year, with a peak between June and August, indicating a continuous reproductive cycle. The ELEFAN method estimated an asymptotic carapace length of 31.19 mm. Catch per unit effort showed notable differences between the sampled areas, being the highest abundances (10.42 g/m<sup>2</sup>/gatherer) recorded at the northern coast and the lowest (5.10 g/m<sup>2</sup>/gatherer) at the southern one. The relative low abundance, particularly in the south coast, in relation with the current allowed catch quotas (1500 g/day/gatherer for artisanal fishing, 200 g/day/gatherer for recreational fishing) and a high number of recreational fishing licenses, indicate that the jaguar round crab stock of the island could be in risk of overfishing. This analysis provided crucial biological information to support management and conservation strategies for <em>X. poressa</em>.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"94 ","pages":"Article 104777"},"PeriodicalIF":2.4,"publicationDate":"2026-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145980967","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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