Regional Studies in Marine Science最新文献

{"title":"Range expansion of two non-indigenous sponges (Porifera) in southern European waters: new records from the Atlantic coast of the Iberian Peninsula","authors":"Jesús Fernández-Gutiérrez,&nbsp;Marcos Rubal,&nbsp;Puri Veiga,&nbsp;Fran Ramil","doi":"10.1016/j.rsma.2026.105295","DOIUrl":"10.1016/j.rsma.2026.105295","url":null,"abstract":"<div><div>The Atlantic coast of the Iberian Peninsula is a region susceptible to the introduction of non-indigenous species (NIS). However, records of NIS sponges remain scarce and often lack of morphological confirmation. Here, we provide evidence for the presence of two NIS sponges, <em>Haliclona (Chalinula) loosanoffi</em> (Demospongiae: Haplosclerida) and <em>Paraleucilla magna</em> (Calcarea: Leucosolenida) in this area, based on surveys conducted in natural and artificial habitats from the Bay of Cádiz to Galicia. <em>Haliclona loosanoffi</em> is native to the northeastern United States and has been previously recorded in northern European waters. In the present study, it was found in northern Portugal, extending its known range southwards. <em>Paraleucilla magna</em> was originally described from Brazil and is now widely distributed in the Mediterranean Sea. Here, it was found in southern Spain and Portugal, and northwestern Spain, representing its northernmost Atlantic occurrence. Both species were predominantly associated with recreational marinas and mussel rafts, highlighting the role of anthropogenic activities in their spread. However, several specimens of <em>Paraleucilla magna</em> were also collected in natural habitats. In addition, worldwide records of both species were compiled from their original descriptions to the present to update their distribution ranges. Our findings extend the known ranges of both NIS in southern European waters, improve the knowledge of Porifera, and emphasize the importance of morphological approaches for invasion management.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"101 ","pages":"Article 105295"},"PeriodicalIF":2.7,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148638205","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Cold seep environment shapes the structure and metabolic potential of mesopelagic fish gut microbiota","authors":"Xiyue Yang,&nbsp;Chunhou Li,&nbsp;Yong Liu,&nbsp;Zuozhi Chen,&nbsp;Yan′e Jiang,&nbsp;Min Li,&nbsp;Yancong Cai,&nbsp;Jian Zou,&nbsp;Shannan Xu,&nbsp;Yayuan Xiao,&nbsp;Yu Liu,&nbsp;Dajuan Zhang,&nbsp;Peng Wu","doi":"10.1016/j.rsma.2026.105256","DOIUrl":"10.1016/j.rsma.2026.105256","url":null,"abstract":"<div><div>Cold seeps, unique deep-sea ecosystems driven by hydrocarbon- and sulfide-rich fluid fluxes, support mesopelagic fish communities. Fish gut microbiota are vital to host metabolism and health, and interact closely with the surrounding water environment. However, information on gut bacterial composition and potential functional profiles of mesopelagic fishes in the cold seep has rarely been explored. In this study, high-throughput sequencing of the 16S rRNA gene was used to compare gut microbiota of mesopelagic fishes collected from the cold seep environment (<em>Bolinichthys longipes</em>, <em>Ceratoscopelus warmingii)</em> and mesopelagic fishes from non-cold seep environment (<em>B. longipes, Diaphus brachycephalus</em>, <em>Diaphus signatus</em>). Significant differences were found in gut bacterial composition and predicted functional profiles between the two distinct fish habitats. Within <em>B. longipes</em>, clear differences in gut bacterial composition were detected between cold seep and non-cold seep populations, suggesting a potential habitat-associated effect. The genera <em>Blastopirellula</em>, <em>Ruegeria</em>, and <em>Rubripirellula</em>, which are known to be involved in sulfide and hydrocarbon transformations, were significantly more abundant in cold seep fish (<em>p</em> &lt; 0.05). In contrast, <em>Acinetobacter</em> was significantly enriched in fish outside the cold seep (<em>p</em> &lt; 0.05). The differences in gut bacterial composition between the two habitats were primarily driven by the “abundant” subcommunities. Co-occurrence network analysis revealed more complex gut microbiome networks in cold seep fishes. Functional predictions using FAPROTAX showed that the gut microbiome associated with cold seep fish harbored higher predicted functional potential related to methane-, nitrogen-, and sulfur-associated processes. Meanwhile, PICRUSt2 analyses indicated a higher representation of predicted pathways associated with lipid metabolism and hydrocarbon degradation under cold seep conditions. Together, these results suggest that the cold seep environment may influence the structure and predicted functional potential of mesopelagic fish gut microbiota.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"101 ","pages":"Article 105256"},"PeriodicalIF":2.7,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148638216","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":"A case study for source identification of oil spilled to the ocean and shoreline near Postville, Labrador, Canada","authors":"Zeyu Yang,&nbsp;Keval Shah,&nbsp;Bruce P. Hollebone,&nbsp;Chun Yang,&nbsp;Patrick Lambert,&nbsp;Graham Thomas,&nbsp;Blain Trainor,&nbsp;Vanessa Beaulac","doi":"10.1016/j.rsma.2026.105318","DOIUrl":"10.1016/j.rsma.2026.105318","url":null,"abstract":"<div><div>This study investigates the 2020 oil spill near Postville, Labrador, using forensic chemical fingerprinting to identify the source of contamination. Petroleum hydrocarbons and biomarker profiling were applied to characterize hydrocarbon signatures in environmental samples and compare them with potential sources. Hydrocarbon group analysis excluded gasoline and lubricating oil, while <em>n</em>-alkane distributions and diagnostic ratios indicated a strong correlation with kerosene. Low levels of terpanes, and hopanes, and polycyclic aromatic hydrocarbons (PAHs) most abundant with low molecular weight congeners were found in most environment samples, consistent with light fuel oils, like kerosene and marine diesel. Diamantane and bicyclic sesquiterpene ratios aligned with both kerosene and marine diesel. Bilge water contained hetero-sulfur alkylated PAHs and aromatic steranes, differing from kerosene and marine diesel. Multivariate analyses, including principal component and hierarchical clustering, confirmed the strongest link to light fuel oils, kerosene and marine diesel, both are the possible sources for most environmental samples. These findings demonstrate the effectiveness of oil forensic techniques in source attribution and environmental management.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"101 ","pages":"Article 105318"},"PeriodicalIF":2.7,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148738877","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Quantifying the Shoreline Response to Living Shoreline Implementation along Hull Springs, Virginia, using integrated Remote Sensing techniques","authors":"Ravi Darwin Sankar,&nbsp;Sarah Lacy,&nbsp;Matthew Wright","doi":"10.1016/j.rsma.2026.105315","DOIUrl":"10.1016/j.rsma.2026.105315","url":null,"abstract":"<div><div>A grand challenge exists to translate our current knowledge of climate variability, and its amplified signals, into reliable information relevant to sustainably protecting coastal and inland communities. This research is an integration of ground-based and remote sensing data demarcating the location of the dynamic land-water interface and its analysis to enumerate change along an ∼300-meter frontal shoreline segment beside the Baliles Center at Hull Springs, located in Westmoreland County, Virginia. A time series of shoreline data covering the period 1937–2025 was obtained and the Analyzing Moving Boundaries Using R methodology was used to quantify rates of shoreline movement, comparing sections with and without nature-based stabilization. The analysis revealed a dominant erosional signal along the non-fortified portion of the study area, with approximately 98% of the shoreline retreating landward over the most recent interval (2009–2025). Results indicate that installation of the living shoreline in 2008 has worked to increase resilience of the shoreline behind the sill-based structure by significantly reducing the erosional signature even during short-term events of elevated hydrodynamics. Further, this study notes a variability in wave energy and sediment transport alongshore, with the updrift living shoreline area generally experiencing reduced direct wave impact and the adjacent non-fortified shoreline segment subjected to higher wave energy, altered sediment budgets and an increase in the spatial extent and rate of erosion over the short-term period. With warming conditions, anthropogenic changes and storminess predicted to increase in this region, coastal managers should prepare for accelerated rates of retreat (∼ −0.22 m/yr.) in the immediate vicinity of the non-stabilized coastal segment. This investigation reinforces the view that living shorelines reduce lateral erosion and promote short-term shoreline stability in micro-tidal areas.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"101 ","pages":"Article 105315"},"PeriodicalIF":2.7,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148738878","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":"Mercury speciation and pollution assessment of small-scale gold mining impacted sediments in Gumaus Bay, Camarines Norte (the Philippines)","authors":"Rico Neil M. Quierrez,&nbsp;Jessie O. Samaniego,&nbsp;Fern Rose A. Peregrino,&nbsp;Joe Ervin Y. Flores,&nbsp;Karl Aaron G. Saur,&nbsp;Virgil B. Bilaro,&nbsp;Angel T. Bautista VII","doi":"10.1016/j.rsma.2026.105326","DOIUrl":"10.1016/j.rsma.2026.105326","url":null,"abstract":"<div><div>Paracale Mineral District in Camarines Norte hosts small-scale gold mining (SSGM) communities that still use mercury amalgamation for their gold processing. Tailings from SSGM facilities drain to Gumaus Bay and pose risks to human and aquatic environments. In this study, surface marine sediments were collected from Gumaus Bay and analyzed for mercury and other potentially toxic elements (As, Cd, Cr, Cu, Ni, Pb, and Zn). Total mercury ranges from 0.0292 to 1.0979 mg/kg, with the highest concentrations recorded in the southwestern part of the bay proximal to the Luklukan River mouth. Mercury speciation suggests oxidation of elemental mercury (Hg0) coming from the ball mill facility to Hg(I) into the marine environment. Further transformation of these mercury species could enhance bioavailability and could pose potential ecological risks. Index of geoaccumulation (I_Geo) shows the bay is uncontaminated to moderately contaminated with Zn, As, Cd, Ni, and Hg, and moderately contaminated with Pb and Cr. While enrichment factor values show deficiency to minimal enrichment of Cu and Mn, moderate enrichment of Cd, Co, and Ni, and significant enrichment of Pb, Zn, As, Cr, and Hg. Based on the sediment quality guidelines, 11.8%, 70.6% and 17.6% of all samples rarely, occasionally, and frequently occur and cause adverse biological effects in aquatic biota, respectively. This study suggests further monitoring and implementation of sustainable management strategies to mitigate the ongoing risks posed by small-scale gold mining activities to the Gumaus Bay local environment.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"101 ","pages":"Article 105326"},"PeriodicalIF":2.7,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148740175","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":"Spatiotemporal patterns and environmental drivers of benthic foraminiferal communities in the mangroves of Yanpu Bay, China","authors":"Ling Qiao,&nbsp;Jingwen Song,&nbsp;Junting Chen,&nbsp;Tiejun Li,&nbsp;Yuanming Guo","doi":"10.1016/j.rsma.2026.105301","DOIUrl":"10.1016/j.rsma.2026.105301","url":null,"abstract":"<div><div>Mangroves are critical tropical and subtropical coastal ecosystems that provide essential ecological and societal services. As sensitive bioindicators of sedimentary environments, benthic foraminifera respond rapidly to environmental changes, making them valuable for assessing the health status of mangrove ecosystems. In this study, surface sediment samples were collected from Yanpu Bay, a hotspot of northern marginal mangrove research in China, in May and December 2024. A total of four orders (Astrorhizida, Miliolida, Allogromiida, Rotaliida) and eleven genera were identified using environmental DNA (eDNA) and environmental RNA (eRNA) metabarcoding, with <em>Ovammina</em> showing the highest mean relative abundance. The benthic foraminiferal community exhibited distinct spatiotemporal patterns. Spatially, the relative abundance of calcareous taxa decreased from transect A to transect E, whereas that of agglutinated taxa increased. Seasonally, calcareous taxa were less abundant in May than in December, while agglutinated taxa showed the opposite trend. Canonical correspondence analysis (CCA) revealed that organic carbon (OC) was the most significant environmental driver shaping the spatiotemporal patterns of benthic foraminiferal communities. These findings provide a scientific basis for using benthic foraminifera as bioindicators in mangrove ecological monitoring and restoration assessment.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"101 ","pages":"Article 105301"},"PeriodicalIF":2.7,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148638157","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":"Chemical contaminants and microplastics in bivalves from São Paulo coast: A systematic approach supporting management strategies","authors":"Yonara Garcia,&nbsp;Victor Vasques Ribeiro,&nbsp;Caio César Achiles Do Prado,&nbsp;Marina De Souza Paço,&nbsp;Ítalo Braga Castro","doi":"10.1016/j.rsma.2026.105305","DOIUrl":"10.1016/j.rsma.2026.105305","url":null,"abstract":"<div><div>Bivalves are widely used as sentinels of chemical and microplastic contamination in coastal environments. The coastline of São Paulo State, is one of the most densely populated and industrialized coastal regions in the Southern Hemisphere, overlapped with a mosaic of marine protected areas. Evidence on contamination of resident bivalves remains fragmented across chemical classes, species, and geographic sectors. Here, we present a systematic review of chemical and microplastic contaminants based on bivalves along the São Paulo coast, synthesizing 30 peer-reviewed studies published between 2000 and 2025. The review encompasses toxic metals and metalloids, hydrocarbons, persistent organic pollutants, microplastics, and drugs of abuse, complemented by an assessment of bibliometric patterns and knowledge gaps. Metals dominated the literature (54.6%) and spanned the longest temporal range (analysis period: 1995–2023), whereas hydrocarbons, microplastics, and persistent organic pollutants were investigated less frequently and were largely restricted to estuarine and port-influenced environments. Sentinel use was strongly based in few mussel and oyster species, while research effort was highly concentrated in the Santos–São Vicente Estuarine System. Although fewer studies were conducted within marine protected areas, contaminant levels were generally lower than in unprotected sites, suggesting localized mitigation effects but not complete protection. Overall, the findings reveal a compartmentalized monitoring landscape characterized by limited integration among contaminant classes and uneven spatial coverage. This review provides the first consolidated synthesis of bivalve contamination along the São Paulo coast and identifies priority gaps to support the development of harmonized, multi-contaminant biomonitoring frameworks in highly urbanized coastal systems.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"101 ","pages":"Article 105305"},"PeriodicalIF":2.7,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148658774","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Size selectivity of hand dredges targeting black clam (Villorita cyprinoides)","authors":"V.R. Madhu,&nbsp;Bent Herrmann,&nbsp;Jure Brčić,&nbsp;Megha Madhav,&nbsp;K.K. Mohammed Jabir","doi":"10.1016/j.rsma.2026.105243","DOIUrl":"10.1016/j.rsma.2026.105243","url":null,"abstract":"<div><div>Black clam (<em>Villorita cyprinoides</em>) fisheries in India support thousands of small-scale fishers and account for more than 90% of estuarine clam landings in Kerala. Harvesting is conducted using hand-held dredges, yet the selectivity of these gears has never been quantified. Recent adoption of small mesh sizes in the fishery has raised concerns regarding retention of juveniles below the minimum legal width (MLS = 20 mm). This study experimentally quantifies the size selectivity of hand dredges equipped with two mesh sizes in Vembanad Lake (25 and 30 mm nominal). Furthermore, clam morphometrics were measured to develop a morphology-based predictive framework for dredge size selectivity by linking clam circumference to mesh circumference. Among five hypothesized shell–mesh contact modes, one mode reproduced the experimental selectivity curves for both dredges with high accuracy (R² &gt; 0.999), indicating that retention is primarily governed by geometric constraints. Model predictions demonstrate that the recent adoption of smaller meshes (18 mm – 20 mm) shifts the 50% retention rate below the MLS, whereas meshes of approximately 28–29 mm are a better match. This study provides the first quantitative assessment of hand dredge selectivity in a tropical estuarine clam fishery and establishes a mechanistic basis for evidence-based mesh regulation, offering a framework that can guide mesh regulations for clam fisheries worldwide.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"101 ","pages":"Article 105243"},"PeriodicalIF":2.7,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148658845","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A decade of summer tourist-litter dispersion and beach connectivity in the gulfs of Chalkidiki (North Aegean Sea): A Lagrangian assessment with open-data tourism-pressure weighting","authors":"Vassilios Papaioannou,&nbsp;Dimitrios Valsamis,&nbsp;Anastasia Moumtzidou,&nbsp;Ilias Gialampoukidis,&nbsp;Stefanos Vrochidis,&nbsp;Ioannis Kompatsiaris","doi":"10.1016/j.rsma.2026.105331","DOIUrl":"10.1016/j.rsma.2026.105331","url":null,"abstract":"<div><div>Mediterranean tourist coasts are intense seasonal sources of plastic litter, yet where summer beach litter actually travels, and which beaches export it to the wider basin, remains poorly resolved at the scale of individual resorts. We present a decade-long (summers 2016–2025) Lagrangian assessment of floating macro-litter released from twelve tourist beaches on two peninsulas of Chalkidiki (North Aegean Sea). Surface drift was simulated with the OpenDrift OceanDrift model forced by Copernicus Marine 4.2 km currents and Stokes drift and ERA5 winds, seeding plastic continuously through each summer with a novel, fully reproducible source weighting derived from open OpenStreetMap tourist-accommodation capacity. Across all ten summers, 99.83–100.00% of released litter stranded locally within the wider Chalkidiki region, close to its source and, in the great majority of cases (≈88%), within the originating gulf, typically within a day (median net travel 2.2–4.1 km), a strikingly robust pattern. Source–sink connectivity, computed with a geographically calibrated gulf classifier, shows the Toronaios and Singitic gulfs to be net litter exporters and the Thermaikos Gulf the principal net importer (retaining only 78.2% of locally produced litter while receiving cross-gulf inputs). Only a small fraction (≤0.17% in any summer) was still afloat in open water when each run ended, a residual that scaled positively with summer Etesian wind strength (r = 0.41); physical export beyond the analysis domain was negligible (10 of 1.1 million particles over the decade). An export-risk ranking that combines release weight with cross-gulf leakage identifies Kallithea and Possidi as the dominant contributors to cross-gulf pollution and thus priority targets for prevention. A Sentinel-2 floating-debris-index analysis detects no persistent offshore aggregations, consistent with this diffuse, fast-stranding fate. The framework is transferable to any tourism-dominated coast and its outputs translate directly into beach-scale management priorities.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"101 ","pages":"Article 105331"},"PeriodicalIF":2.7,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148740173","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"No signs of recovery: The long-term consequences of harvesting on a South American sea lion population in Uruguay","authors":"Valentina Franco-Trecu,&nbsp;Diana Szteren,&nbsp;Massimiliano Drago,&nbsp;M. Florencia Grandi,&nbsp;Enrique A. Crespo,&nbsp;Alvaro Soutullo","doi":"10.1016/j.rsma.2026.105308","DOIUrl":"10.1016/j.rsma.2026.105308","url":null,"abstract":"<div><div>Understanding long-term population trajectories is essential for effective wildlife management, particularly in exploited species. In Uruguay, the South American sea lion was subjected to intense commercial harvesting throughout much of the 20th century; however, post-exploitation population trajectories remain poorly documented in the country. We assessed long-term demographic trends of the two main Uruguayan rookeries, Isla de Lobos and Cabo Polonio, both Marine Protected Areas, by compiling historical pup counts (1953–2000) and conducting standardized aerial photographic surveys in 2011, 2013, and 2017. Pup abundance was estimated from aerial mosaics, corrected for detection bias, and analysed using log-linear regression to estimate annual rates of change. Between 1956 and 2017, pup production in Uruguay declined significantly at a mean annual rate of 1.9%. Cabo Polonio remained relatively stable, exhibiting only a weak and non-significant decline (–0.7% yr⁻¹), whereas Isla de Lobos showed a strong and significant annual decline of approximately 5.0%. In 2017, estimated pup abundance reached 2006 at Cabo Polonio and only 299 at Isla de Lobos. These contrasting trajectories likely reflect the legacy of intensive commercial exploitation at Isla de Lobos, where approximately 47,000 pups were removed over 24 years, followed by the continued extraction of live non-breeding individuals for zoos and aquariums. Limited demographic rescue between colonies, ongoing anthropogenic pressures, and recent stochastic events (including the 2023 outbreak of highly pathogenic avian influenza (HPAI H5N1)), further increase vulnerability of the Uruguayan colonies. Our findings underscore the need for sustained monitoring and colony-specific management to promote long-term population resilience in Uruguay.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"101 ","pages":"Article 105308"},"PeriodicalIF":2.7,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148740176","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}