Regional Studies in Marine Science最新文献

{"title":"Comparison of efficiency of spectral (NDWI) and SAR (GRD) method in shoreline detection: A novel method of integrating GRD and SLC products of sentinel-1 satellite","authors":"Rahimeh Shamsaie ,&nbsp;Danial Ghaderi","doi":"10.1016/j.rsma.2025.104132","DOIUrl":"10.1016/j.rsma.2025.104132","url":null,"abstract":"<div><div>In the context of shoreline change studies for management and development purposes, it is essential to utilize historical shoreline positions. Today, various satellite methods and images are utilized; for instance, the capabilities of contemporary spectral images are well established. However, given the efficiency of Synthetic Aperture Radar (SAR) images in providing earth observations under all weather conditions, their use for identifying shoreline positions is increasingly being developed. This study presents a comparative analysis of shoreline extraction using the Ground Range Detected (GRD) and GRD-SLC (Single Look Complex) methods, alongside the spectral method as a reference. The GRD-SLC method significantly improved accuracy, particularly in estuarine areas, reducing median discrepancies from 378.0 m ( ± 247.7) with the GRD method to 16.0 m ( ± 26.6) for this type of shores. For steep rocky shores, the discrepancy decreased from 22.1 m ( ± 18.4) to 8.5 m ( ± 10.1). Conversely, the GRD method performed better for dune-backed, wide sandy, and rocky shores. Overall, the GRD-SLC method yielded a discrepancy of less than 50 m in key areas like omega-shaped beaches and cliffs, with its best performance observed in low-elevation regions (&lt;10 m). The findings emphasize the GRD-SLC method’s suitability for diverse coastal environments. Despite the limitations of the GRD method, its all-weather SAR imagery capability proves effective on a regional scale. This study highlights the need for further algorithmic advancements in SAR-based shoreline monitoring to enhance accuracy across varying coastal terrains.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"84 ","pages":"Article 104132"},"PeriodicalIF":2.1,"publicationDate":"2025-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143637699","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}

{"title":"Nature-based solutions implications for the eastern Amazon Coastline: The role of mangrove in coastal protection","authors":"Vando J.C. Gomes ,&nbsp;Fernanda Minikowski Achete ,&nbsp;Pedro Paulo de Freitas ,&nbsp;Wanessa Karoline Lima e Silva ,&nbsp;Camilo A. Guerrero Martin ,&nbsp;Eduardo Vitarelli Queiroz ,&nbsp;Juliana de Sá Guerreiro ,&nbsp;Nils E. Asp ,&nbsp;Eduardo Siegle ,&nbsp;Edinelson Saldanha Correa","doi":"10.1016/j.rsma.2025.104129","DOIUrl":"10.1016/j.rsma.2025.104129","url":null,"abstract":"<div><div>The coastal region serves as a crucial link between the ocean and the mainland, with its morphology significantly shaped by seasonal meteorological and oceanographic conditions. This study was conducted in Salinópolis, located in the state of Pará in northern Brazil, along the eastern sector of the Amazon coast. This area is characterized by a coastal system influenced by semi-diurnal macro tides and waves, alongside notable seasonality in rainfall patterns. Data collection occurred during 2022 and 2023, encompassing both dry and rainy seasons and including neap and spring tides. Observations were made at two sites: a mangrove forest (P1) and a reconstructed retaining wall (P2) designed to mitigate erosion. The data collected included current speed and direction, turbidity, and salinity. Results revealed a 70–80 % reduction in current velocity at the mangrove site (P1) compared to the retaining wall site (P2), underscoring the mangrove forest’s effectiveness in dampening wave and tidal energy. Salinity varied significantly between the dry (∼30 PSU) and rainy (∼8 PSU) seasons, showing a 70 % reduction. Additionally, suspended sediment concentration was higher during the rainy season (∼114 mg/L), representing an 80 % increase compared to the dry season (∼29 mg/L), attributed to higher sediment input from local rivers. This study represents the first evaluation of mangrove forests as nature-based solutions for coastal protection in the Amazon region. It highlights the potential of such ecosystems not only for coastal preservation but also for the conservation of the region’s threatened biodiversity, which is increasingly at risk due to coastal urban development.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"84 ","pages":"Article 104129"},"PeriodicalIF":2.1,"publicationDate":"2025-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143637271","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}

{"title":"Enhancing carbon neutrality through blue carbon fisheries: Spatial analysis in Shandong","authors":"Jing Sun ,&nbsp;Mengfei Li ,&nbsp;Ningning Zhai ,&nbsp;Hairong Mu ,&nbsp;Weixiao Li ,&nbsp;Huining Liu","doi":"10.1016/j.rsma.2025.104125","DOIUrl":"10.1016/j.rsma.2025.104125","url":null,"abstract":"<div><div>China has embraced the dual-carbon targets and has consistently pursued a trajectory of green recovery and green transformation since 2020. Actively promoting carbon sink fishery proves to be a cost-effective means of fulfilling the commitment to reduce carbon emissions. This study quantifies the carbon sequestration of blue carbon fisheries in seven coastal cities of Shandong province from 2016 to 2021, delving into their spatial-temporal evolutionary characteristics. Employing spatial correlation analysis, we utilize the spatial Durbin model with a double fixed effect to explore influencing factors and spatial spillover effects. Our findings reveal a fluctuating upward trend in fishery carbon sink within Shandong province, showcasing significant spatial correlation and spillover effects in coastal regions. Firstly, the carbon sink changing trend in coastal cities diverges from 2016 to 2021, with a distribution trend characterized by “more in the east and less in the west”. Secondly, the global Moran’s <em>I</em> indicates a positive spatial correlation in each region, while local Moran’s <em>I</em> identifies three types of spatial agglomeration: H-H, L-H, and L-L. Thirdly, economic development, mariculture structure, and fishery technology exhibit positive direct effects, while the direct effect of fishery labor force is negative according to the decomposed spatial Durbin model. From the perspective of indirect effects, the level of economic development has diffusion effect on adjacent areas, mariculture structure has a negative spillover effect, and the fishery labor force induces a polarization effect on the neighborhood. Based on the findings, this paper proposes suggestions in three main areas: promoting spatial development, optimizing cultivation practice, and encouraging research and innovation.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"85 ","pages":"Article 104125"},"PeriodicalIF":2.1,"publicationDate":"2025-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143686293","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}

{"title":"Variation in growth, condition, physiological and prey-predator status of smoothbelly sardinella, Amblygaster leiogaster (Valenciennes, 1847) in the Bay of Bengal","authors":"Md. Ashekur Rahman,&nbsp;Most. Shakila Sarmin,&nbsp;Md. Akhtarul Islam,&nbsp;Md. Yeamin Hossain","doi":"10.1016/j.rsma.2025.104110","DOIUrl":"10.1016/j.rsma.2025.104110","url":null,"abstract":"<div><div>This study estimated the first report on temporal and seasonal variation in growth patterns, condition factors (Fulton’s, <em>K</em>_<em>F</em>; Relative, <em>K</em>_<em>R</em>), physiological and prey-predator status of <em>Amblygaster leiogaster</em> (Valenciennes, 1847) from the Bay of Bengal, Bangladesh through sampling from January to December 2020. Collected individuals (1337) were measured with an accuracy of 0.01 g for body weight (BW) and 0.1 cm for total length (TL), respectively. The growth pattern was evaluated through studying the length-weight relationships. The study recorded new maximum length (30.50 cm TL) and weight (142.56 g) for this species. This species revealed an overall negative allometric (<em>b</em> = 2.61) growth. Temporal variation indicated a positive allometric growth in September, October and November. However, an isometric growth pattern (<em>b</em> = 3.08) was found in post-monsoon while other season demonstrated negative allometric growth. The overall <em>K</em>_<em>F</em> was 0.50–1.20, and <em>K</em>_<em>R</em> was 0.66–1.35 for <em>A. leiogaster</em>. The overall <em>K</em>_<em>F</em> showed a strong correlation with TL, while the <em>K</em>_<em>R</em> demonstrated correlations with both TL and BW. Most of the fatty fish found in winter (51.43 %) with a minimum number of lean fish (21.14 %) while maximum ideal fish was in post-monsoon (55.77 %). The <em>W</em>_<em>R</em> stated that the Bay of Bengal had been considered stable for <em>A. leiogaster</em>. The findings provided valuable insights on the stock health of <em>A. leiogaster</em> that assist in developing efficient management in the Bay of Bengal and other habitats.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"84 ","pages":"Article 104110"},"PeriodicalIF":2.1,"publicationDate":"2025-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143577058","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}

{"title":"Differential response in land use pattern, haematological parameters and growth of mudskipper (Apocryptes bato) at different salinities","authors":"Joya Chakrabarty ,&nbsp;Azmaien Naziat ,&nbsp;Abida Sultana ,&nbsp;Md. Main Uddin Mamun ,&nbsp;Fatema Akhter ,&nbsp;Md. Moudud Islam ,&nbsp;Md. Shahjahan ,&nbsp;Md. Mahiuddin Zahangir","doi":"10.1016/j.rsma.2025.104121","DOIUrl":"10.1016/j.rsma.2025.104121","url":null,"abstract":"<div><div>Salinity is one of the ecological factors directly linked to the aquatic ecosystem and regulates the physiology of fish. To date very few is known about the aftereffects of salinity change due to climate change on the coastal species, especially the common intertidal mangrove mudskipper, <em>Apocryptes bato</em> (Gobiidae: Oxodurcinae), a commercially important fish species. In this study, <em>A. bato</em> was subjected to different salinities (5, 10, 12 and 15 ‰) for a period of 21 days. Salinity significantly influenced the land-use pattern diurnally in this species. At 5 and 15 ‰, mudskipper was found to spend significantly higher time on land during nighttime and in saline water during daytime compared to the 10 and 12 ‰. However, behavioural observations in the aquarium did not show significant alterations in the amount of time spend on land or water by individuals nor there were differences in the number of holes, channels in the mud, jumping, or feeding. Haematological analysis after 21 days of rearing showed elevated blood glucose levels in fish reared at 5 and 15 ‰ indicating stressful conditions at these salinities. In addition, higher frequencies of cellular and nuclear abnormalities such as twin cell, nuclear budding, micronucleus, bi-nucleus, triplet cell, tear-dropped cell, multiple nuclei and dead cells were observed in fish reared at 5 and 15 ‰. The growth of <em>A. bato</em> was also significantly impacted by the salinities with higher growth performance at 10 and 12 ‰ compared to 5 and 15 ‰. The findings of the present study suggest that both decreased and increased salinity significantly affected the land use pattern, haematology and growth of mudskippers which could be helpful in the conservation, management and coastal aquaculture.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"84 ","pages":"Article 104121"},"PeriodicalIF":2.1,"publicationDate":"2025-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143621122","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}

{"title":"Spatio-temporal graph neural network fused with maritime knowledge for predicting traffic flows in ports","authors":"Qiang Mei ,&nbsp;Zhaoxuan Li ,&nbsp;Qinyou Hu ,&nbsp;Xiaoying Zhi ,&nbsp;Peng Wang ,&nbsp;Yang Yang ,&nbsp;Xiliang Liu","doi":"10.1016/j.rsma.2025.104106","DOIUrl":"10.1016/j.rsma.2025.104106","url":null,"abstract":"<div><div>The COVID-19 pandemic highlighted significant challenges in maritime industries, such as port congestion and supply chain disruptions, necessitating accurate port traffic prediction. Traditional models often fail to capture the complex and dynamic interactions within maritime networks, particularly the spatial correlations between ports. To address these limitations, this study proposes a spatio-temporal graph neural network (MSTGNN) tailored for maritime traffic prediction. MSTGNN integrates temporal and spatial features using a sample convolution and interaction network (SCINet) and a graph attention network (GAT), enhanced by a k-core mechanism for prioritizing key ports. Extensive experiments with global and regional datasets demonstrate MSTGNN's superior performance in accuracy, stability, and adaptability compared to existing models. The model excels in predicting traffic flows across different ship types, making it highly applicable for optimizing port operations, route planning, and mitigating supply chain risks. The findings imply that MSTGNN can significantly enhance decision-making in maritime logistics by offering more precise traffic predictions, thereby supporting more efficient, resilient, and sustainable global supply chains.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"85 ","pages":"Article 104106"},"PeriodicalIF":2.1,"publicationDate":"2025-03-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143686294","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}

{"title":"Influence of biotic and abiotic factors on mesozooplankton and fish larvae community structures in a fisheries resource protected area: A case study of Gangjin Bay, Korea","authors":"Seong Yong Moon ,&nbsp;Jeong-Ho Park ,&nbsp;Hyun Suk Jung ,&nbsp;Changsin Kim","doi":"10.1016/j.rsma.2025.104114","DOIUrl":"10.1016/j.rsma.2025.104114","url":null,"abstract":"<div><div>Mesozooplankton and fish larvae are critical components of aquatic food webs, and their community structure is essential for effective fisheries management. However, since 1999, no data on these communities have been recorded in Gangjin Bay, Korea, a designated Fisheries Resources Protected Area and a crucial spawning and nursery ground for various fish species. This study investigated the community structure of mesozooplankton and fish larvae in Gangjin Bay from March to November 2022 through monthly sampling. In spring, <em>Noctiluca scintillans</em> dominated, while copepods and cirripedian larvae prevailed in summer and autumn, respectively. The biotic and abiotic factors influencing the community structure of <em>Paracalanus orientalis</em> and <em>Acartia ohtsukai</em> included water temperature and concentrations of chlorophyll <em>a</em> in the micro- and pico-fractions. The biotic and abiotic factors influencing the community structure of anchovy and goby larvae included the abundance of <em>P. orientalis</em> and <em>A. ohtsukai</em>, while those affecting <em>Sebastes inermis</em> larvae were influenced by the abundance of <em>Calanus sinicus</em> and mesozooplankton biomass, particularly in the 1.0-mm size class. This study provides baseline data to describe the community structure of mesozooplankton and fish larvae in Gangjin Bay, thereby contributing to the development of policies for fisheries resource protection and management.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"85 ","pages":"Article 104114"},"PeriodicalIF":2.1,"publicationDate":"2025-03-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143686291","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}

{"title":"Evaluating conservation value and development potential of South Andaman beaches through environmental function analysis","authors":"Swagata Bera ,&nbsp;Dipanjan Das Majumdar","doi":"10.1016/j.rsma.2025.104116","DOIUrl":"10.1016/j.rsma.2025.104116","url":null,"abstract":"<div><div>The Andaman Islands, known for their rich biodiversity, demonstrate the intricate nature of the situation, as growing tourism and human activities pose a threat to the fragile ecological balance. This study utilized the Environmental Function Analysis (EFA) technique to evaluate the conservation and development capabilities of twenty-five beaches in the South Andaman district. The functional analysis approach entailed identifying a comprehensive array of environmental and socio-economic variables. These variables were subsequently evaluated and standardized to ascertain the conservation value and development potential of each beach. By plotting these scores on a conservation/ use/development matrix, the beaches were classified into three distinct categories: conservation, conflict, and development. The findings revealed a diverse range of beach conditions across the South Andaman district. Five beaches were designated for the conservation zone due to their high ecological value, including Natural Arch, Jolly Buoy Island, Soal Bay, Rutland, and Cinque Island. In contrast, two beaches, Corbyn's Cove and Govinda Nagar, were categorized as development-oriented, influenced primarily by socio-economic factors. The remaining eighteen beaches fell within the conflict zone, where conservation and development potentials were relatively balanced. The conservation scores ranged from 0.50 to 0.91, while development potential scores varied from 0.40 to 0.87, highlighting the diverse management needs across the study area. This analysis also identified key environmental indicators, such as biodiversity richness and ecosystem integrity, and socio-economic factors, including tourism infrastructure and local livelihoods, as critical in determining the management approach for each beach. The insights acquired from the environmental function analysis of South Andaman's beaches highlight the effectiveness of this methodology in managing the complex relationship between ecological preservation and economic advancement in small island coastal regions. The adaptability, holistic perspective, and collaborative approach of this study can help formulate adaptive and inclusive management techniques to conserve these unique and fragile island environments.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"85 ","pages":"Article 104116"},"PeriodicalIF":2.1,"publicationDate":"2025-03-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143686287","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}

{"title":"Modelling the abundance of key aquatic species in a tropical Indian estuary using biotic and abiotic predictors","authors":"Sreekanth Giri Bhavan ,&nbsp;Bappa Das ,&nbsp;E.B. Chakurkar ,&nbsp;Dani Thomas ,&nbsp;Chandrasekhar Vasudevan ,&nbsp;Sahna Don","doi":"10.1016/j.rsma.2025.104119","DOIUrl":"10.1016/j.rsma.2025.104119","url":null,"abstract":"<div><div>Species distribution modelling (SDM) is a method that assists in linking the biotic and abiotic features of the ecosystems. In this study, we developed SDMs for total fish abundance, abundance of <em>Escualosa thoracata</em> (ET)<em>, Mugil cephalus</em> (MC)<em>, Sardinella longiceps</em> (SL) and <em>Fenneropenaeus merguiensis</em> (FM) based on biotic and abiotic variables using multivariate statistical techniques such as Regression tree (RT), Support Vector Machine (SVM), K-nearest neighbours (kNN), Gaussian process regression (GPR), Random Forest (RF), eXtreme Gradient Boosting (XGB), Cubist, and Quantile random forest (QRF). A combination of abiotic and biotic variables such as salinity, temperature, mud, turbidity, zooplankton, shell debris, sand, and benthos were identified as the significant predictors for the distribution of total fish abundance and species wise fish abundance. The model performance was evaluated based on coefficient of determination (R²), d-index, mean bias error (MBE), Nash–Sutcliffe efficiency (NSE) and root mean squared error (RMSE). A unique average ranking procedure was followed using all the model evaluation indicators to select a best model for a given season or species. The top performing models did not vary much between the seasons and species. We identified the following models performed best for different species respectively during postmonsoon and premonsoon seasons- Cubist and QRF for <em>E. thoracata,</em> RF and GLMNET for <em>M. cephalus,</em> SVM and QRF for <em>S. longiceps</em>, GPR and QRF for <em>F. merguiensis.</em> The major variables influenced the species distribution were benthic substratum (sand, mud, shell debris), chlorophyll-a and depth. Thus, it is evident that though the other variables also influence the distribution and abundance of the species in an estuarine bay, the benthic features, depth and morphometry can have significant effect on the species distribution. Moreover, the advanced multivariate statistical tools can aid in the prediction of the species distribution in the tropical estuaries.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"85 ","pages":"Article 104119"},"PeriodicalIF":2.1,"publicationDate":"2025-03-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143696668","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}

{"title":"First record of the scoophead shark (Sphyrna media) and new records of great hammerhead sharks (Sphyrna mokarran) in the Guatemalan Pacific","authors":"Ana Cristina Hérnandez ,&nbsp;Julio Sánchez-Jiménez ,&nbsp;María de los Angeles Rosales-Melgar ,&nbsp;Elisa M. Areano-Barillas ,&nbsp;Juan Carlos Pérez-Jiménez","doi":"10.1016/j.rsma.2025.104122","DOIUrl":"10.1016/j.rsma.2025.104122","url":null,"abstract":"<div><div>A juvenile scoophead shark (<em>Sphyrna media</em>) and four juvenile great hammerhead sharks (<em>Sphyrna mokarran</em>) captured with longlines (&lt; 30 m depth) by small-scale fisheries off the coast of Buena Vista and Sipacate in the Guatemalan Pacific are reported. These species are categorized as Critically Endangered by the IUCN Red List, primarily due to overfishing. All the specimens were juveniles: a male <em>S. media</em> (71 cm TL) and four <em>S. mokarran</em>, including a female (114 cm TL) and three males (79.5, 122, and 149.5 cm TL). <em>Sphyrna mokarran</em> specimens recorded in our study are the smallest ever reported for the Eastern Pacific region. <em>Sphyrna media</em> specimen is the first recorded in the Guatemalan Pacific, increasing the number of hammerhead species to four and the total number of shark species recorded off the Guatemalan Pacific to sixteen.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"84 ","pages":"Article 104122"},"PeriodicalIF":2.1,"publicationDate":"2025-03-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143600650","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}