Regional Studies in Marine Science最新文献

{"title":"Current status and future outlook of aquatic microplastic pollution in Malaysia","authors":"Ishmail Sheriff ,&nbsp;Mabruk Adams","doi":"10.1016/j.rsma.2025.104504","DOIUrl":"10.1016/j.rsma.2025.104504","url":null,"abstract":"<div><div>Microplastics (MP) are generated across the full life cycle of plastics, causing widespread environmental pollution. This review provides a comprehensive analysis of MPs research trend, and knowledge gaps in aquatic organisms in Malaysia. Comparative analyses reveal significant variation in MP ingestion and accumulation, with some fish species, such as sharks and mackerel, harbouring thousands of MPs, indicating widespread contamination. Moreover, bivalves, particularly oysters and blood cockles, act as bioindicators of marine pollution due to their filter-feeding habits, displaying MPs concentrations that threaten food safety. Gastropods, sea cucumbers, and crustaceans also exhibit MP presence, often dominated by fibres and polymers like polyethylene terephthalate (PET), with ingestion likely driven by sediment intake and diet. Data on lower trophic levels, such as zooplankton, polychaetes, and aquatic insects, remain limited, yet existing evidence suggests potential biomagnification and ecosystem disruption, which could exacerbate MP transfer to higher organisms, including humans. Thus, understanding these differential effects underscores the importance of investigating biota-MP interactions to better assess and mitigate the health impacts of environmental MPs pollution. Moreover, mechanistic and long-term toxicological studies remain limited, necessitating the urgency for comprehensive risk assessments. In this regard, enhanced pollutant monitoring, reduced plastic release, and development of safer alternative materials are some of the measures critical to mitigate macro- and microplastic toxicity in aquatic environments.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"91 ","pages":"Article 104504"},"PeriodicalIF":2.4,"publicationDate":"2025-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145159538","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":"Impact of the Russia-Ukraine conflict on the resilience of global shipping supply chains","authors":"Jihong Chen ,&nbsp;Qing Fang ,&nbsp;Chenggang Li ,&nbsp;Xiaofei Xu ,&nbsp;Yufeng Mao ,&nbsp;Feng Yu","doi":"10.1016/j.rsma.2025.104502","DOIUrl":"10.1016/j.rsma.2025.104502","url":null,"abstract":"<div><div>Utilizing panel data from 27 countries spanning the period from 2000 to 2023, this study applies the Quantile Control Method (QCM) to quantitatively investigate the impact of the Russia–Ukraine conflict on the global maritime supply chains resilience. The results indicate that the conflict has significantly reduced the resilience of global maritime supply chains, with the most pronounced declines observed in Europe (15.09%),(15.09 %), Asia (12.09 %), and Africa (7.75 %). In contrast, the conflict did not statistically significant impact on the supply chain resilience in the Americas and Oceania. Specifically, the maritime supply chain resilience of Russia and Ukraine declined by 2.78 % and 1.35 %, respectively. These findings offer empirical evidence to guide policymaking on mitigating the impacts of geopolitical conflicts on maritime supply chains.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"91 ","pages":"Article 104502"},"PeriodicalIF":2.4,"publicationDate":"2025-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145159535","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":"Dynamic water quality criteria for estuaries: Exploration and implementation in the Yangtze Estuary","authors":"Haibiao Zhu ,&nbsp;Peng Zhang ,&nbsp;Deshan Zhou ,&nbsp;Pengxia Liu ,&nbsp;Bin Wu ,&nbsp;Xu Zhao ,&nbsp;Jun Lin ,&nbsp;Hong Huang","doi":"10.1016/j.rsma.2025.104501","DOIUrl":"10.1016/j.rsma.2025.104501","url":null,"abstract":"<div><div>Estuaries, as transitional zones between freshwater and seawater, possess unique attributes rendering the application of the Sea Water Quality Standard for assessment inappropriate and inaccurate. To enhance estuarine environmental protection and management, this study developed a dynamic salinity-based water quality criteria system for the Yangtze River Estuary (YRE), integrating existing marine and surface water standards. The estuary was partitioned into three salinity zones: Tidal-controlled Freshwater Zone (TCFZ), Salinity Transition Mixing Zone (STMZ), and Plume-influenced Marine Zone (PIMZ). Applying this system using survey data from six 2021–2022 cruises revealed a significantly improved comprehensive water quality classification compared to previous marine standards, indicating that the new criteria better characterize the true ecological conditions in each distinct zone. Class III dynamic criteria established nutrient thresholds: DIN (TCFZ: 1.080, STMZ: 0.561, PIMZ: 0.119 mg/L) and SRP (TCFZ: 0.033, STMZ: 0.027, PIMZ: 0.017 mg/L). Combined with hydrodynamic analysis, nitrogen and phosphorus were identified as primary controlling factors, driven by runoff-tide dynamics. This study proposes establishing a real-time, salinity-zone-based monitoring network, implementing seasonal nutrient flux thresholds, and strengthening controls on spring inputs and summer plankton monitoring in the YRE.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"91 ","pages":"Article 104501"},"PeriodicalIF":2.4,"publicationDate":"2025-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145108005","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":"Population structure and beak shape variation in Octopus hubbsorum (Berry, 1953) inferred from microsatellite markers and geometric morphometry in the Mexican Pacific","authors":"José de Jesús Dueñas‑Romero ,&nbsp;José Francisco Domínguez‑Contreras ,&nbsp;Jasmín Granados‑Amores ,&nbsp;María Azucena Alba-Preciado ,&nbsp;Francisco Javier García‑Rodríguez","doi":"10.1016/j.rsma.2025.104500","DOIUrl":"10.1016/j.rsma.2025.104500","url":null,"abstract":"<div><div><em>Octopus hubbsorum</em> (<span><span>Berry, 1953</span></span>) is the most commercially important species in the Mexican Pacific; however, its population aspects and biology have rarely been addressed. It is a benthic species inhabiting rocky and sandy substrates in inter- and subtidal zones. Although some studies have addressed issues related to the life history of <em>O. hubbsorum</em>, little is known about the identification of discrete stocks or populations. The aim of this work was to compare the population structure of the octopus <em>Octopus hubbsorum</em> inferred from microsatellite markers and beak morphometric analysis in the Mexican Pacific. The diversity and population genetic structure of <em>Octopus hubbsorum</em> were inferred using microsatellite-type molecular markers for locations in the Mexican Pacific. Morphological analysis was based on geometric morphometrics of the upper beaks. All the <em>loci</em> were polymorphic, and the genetic diversity was relatively high. Our analysis indicated that the localities do not present significant levels of kinship. With respect to genetic differentiation between populations, the values of <em>F</em>_<em>ST</em> showed evidence of moderate to high differentiation, and Bayesian analysis revealed at least six well-defined populations on the basis of the ADMIXTURE and NO ADMIXTURE models. Principal Components Analysis also suggested the presence of differentiated groups. Geometric morphometric results of the upper beaks also provided compelling evidence of morphological differentiation between the localities. Based on our results, <em>Octopus hubbsorum</em> has a well-defined population in the Mexican Pacific. This understanding can guide the development of targeted conservation and sustainable exploitation strategies.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"91 ","pages":"Article 104500"},"PeriodicalIF":2.4,"publicationDate":"2025-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145120028","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":"Species composition and long-term dynamics of coral reef fishes at Meiji Reef, Nansha Islands","authors":"Hongyu Xie ,&nbsp;Yu Liu ,&nbsp;Yayuan Xiao ,&nbsp;Chunhou Li ,&nbsp;Xuefu Ao ,&nbsp;Jinhui Sun ,&nbsp;Jianzhong Shen ,&nbsp;Yanqiao Wang ,&nbsp;Yong Liu ,&nbsp;Teng Wang","doi":"10.1016/j.rsma.2025.104497","DOIUrl":"10.1016/j.rsma.2025.104497","url":null,"abstract":"<div><div>Meiji Reef, in the east-central Spratly Islands, is a typical coral reef ecosystem with high fish biodiversity. To investigate fish community dynamics, we integrated multiple survey methods (longlining, hand-lining, drift gillnetting, dive fishing, and eDNA) with historical records (1998–1999, 2004, 2012, 2016–2019) and field surveys (2020–2024). The objectives were to characterize community composition, reveal long-term changes from 1998 to 2024, and assess succession following island reclamation. This integrated dataset enabled a systematic analysis of evolutionary trends in fish community structure at Meiji Reef. As of 2024, a total of 353 coral reef fish species have been documented, classified into 162 genera, 61 families, and 14 orders. Small fishes (43.81 %) and carnivorous fishes (74.92 %) dominated the community. We found a marked decline in the number of large carnivorous fish species since the 1998–1999 surveys, alongside an increase in the proportion of small carnivorous fishes and an overall reduction in mean length and weight of carnivorous fishes. The similarity coefficients for carnivorous fish species across different periods were consistently low, categorized as either \"very dissimilar\" or \"dissimilar,\" indicating substantial community turnover. However, during the 2020–2024 period, the proportions of large carnivorous fishes and reef-dependent taxa, such as the Serranidae family, notably increased compared to 2016–2019, whereas proportions of smaller carnivorous species and taxa less dependent on live coral habitats, such as Sheepfishes (Labridae), decreased significantly. These findings suggest a gradual recovery of fish resources following reef reclamation, with increases in large carnivores and coral-associated taxa, and declines in non-coral-dependent taxa. Continuous long-term monitoring is essential for elucidating fish community succession patterns and is critically important for promoting the health and resilience of coral reef ecosystems.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"91 ","pages":"Article 104497"},"PeriodicalIF":2.4,"publicationDate":"2025-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145120026","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":"Modeling management strategies for shrimp farming impact on the coastal delineation near the Northern Bay of Bengal in Bangladesh","authors":"Al Rabby Siemens,&nbsp;Md. Nazrul Islam","doi":"10.1016/j.rsma.2025.104496","DOIUrl":"10.1016/j.rsma.2025.104496","url":null,"abstract":"<div><div>Shrimp farming aquaculture in coastal regions of Bangladesh near the northern Bay of Bengal has become a significant industry contributing notably to nation’s economy through exports and local consumption. Several studies reveal that the shrimp farming leads to significant socioeconomic changes, environmental degradation by heavy metal contamination and toxic substances like NH₃, NO₂−, and H₂S, blue - green algae posing risks to both marine life and human health. Using primary and secondary data including field experiments, FGDs, KIIs and questionnaire surveys in coastal districts, this study aims to analyze perception towards socio-environmental impact of shrimp aquaculture and design an integrated management strategies model for sustaining the shrimp farming practices in coastal world. The statistical test result (F = 1.202, p = 0.312) shows that most of the impact factor variables associated with socio-environmental degradation had no significant effect individually; rather, the combined contributions of multiple variables shaped the complex challenges in coastal arena. To face these, the study develops an Integrated Management Framework applicable in international context for sustainable shrimp farming addressing the environmental, socio-economic and governance strategies through micro, meso and macro scales to guard the combined effects. The framework integrates five established key models (DPSIR, SAF, ERA, SES and EMS) for viable shrimp farming through baseline assessment, stakeholder involvement and governance strategies. Coupled VRIO-SWOT analysis helps to evaluate the model’s competitive advantages and sustainability. The model’s KPIs can offer actionable sustainable approach for international policymakers, industry stakeholders and researchers for enhancing eco-friendly aquaculture practices across diverse international coastal contexts.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"91 ","pages":"Article 104496"},"PeriodicalIF":2.4,"publicationDate":"2025-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145108003","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":"HAMSCNN: A hybrid attention multi-scale CNN for accurate ship detection in maritime surveillance","authors":"Bhoomika Mehta ,&nbsp;Salil Bharany ,&nbsp;Rania M. Ghoniem ,&nbsp;Upinder Kaur ,&nbsp;Tien Anh Tran","doi":"10.1016/j.rsma.2025.104493","DOIUrl":"10.1016/j.rsma.2025.104493","url":null,"abstract":"<div><div>Maritime surveillance is a critical component of global security, trade monitoring, and environmental protection, with ship detection playing a key role in preventing illegal activities and ensuring safe navigation. Satellite imagery, combined with deep learning techniques, has emerged as a powerful solution for real-time ship detection, offering enhanced accuracy and scalability over traditional methods. For the study, a novel deep learning model, Hybrid Attention Multi-Scale CNN (HAMSCNN), is proposed to accurately classify satellite images into Ship and No-Ship categories. The model integrates channel attention, spatial attention, and multi-scale convolution blocks to enhance feature extraction, emphasize critical spatial and channel-wise information, and improve detection across varying ship sizes and oceanic conditions. The dataset comprises 4000 satellite images, with 1000 Ship images and 3000 No-Ship images, addressing the challenge of class imbalance through data augmentation techniques such as flipping, zooming, and rotation. The HAMSCNN model incorporates batch normalization, dropout layers, and max-pooling for improved regularization and stability. Extensive experiments demonstrate that the proposed model significantly outperforms existing state-of-the-art architectures, achieving a classification accuracy of 99 %, with precision, recall, and F1-scores all reaching 0.99. The confusion matrix highlights the model’s reliability, with minimal misclassifications (6 false positives and 4 false negatives), reinforcing its suitability for real-world deployment. The results underscore the potential of HAMSCNN in advancing autonomous ship detection, enabling efficient, cost-effective, and scalable solutions for maritime monitoring. Future work will explore the integration of Synthetic Aperture Radar (SAR) data to enhance robustness under adverse weather conditions and expand the model’s applicability to multi-class maritime object detection.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"91 ","pages":"Article 104493"},"PeriodicalIF":2.4,"publicationDate":"2025-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145108001","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":"16S rRNA gene profiling reveals distinct prokaryotic communities in sediment and seawater habitats of Pattani Bay, Thailand","authors":"Thant Zin Maung ,&nbsp;Theerawut Phusantisampan ,&nbsp;Salinthip Chunwichit ,&nbsp;John Pichtel ,&nbsp;Alapha Thongchai ,&nbsp;Sompong O-Thong ,&nbsp;Weeradej Meeinkuirt","doi":"10.1016/j.rsma.2025.104498","DOIUrl":"10.1016/j.rsma.2025.104498","url":null,"abstract":"<div><div>Coastal habitats are rich in biodiversity that offer multifunctional ecosystem services. Understanding the roles of microbial dynamics and their distribution patterns is essential for ecosystem quality assessment, which, in turn, helps to decipher associated metagenomic insights. The study integrated 16S rRNA gene-targeted metagenomic data with environmental properties using sediment and seawater from selected coastal habitats (industrial, residential, protected) in Pattani Bay, Thailand. In the industrial-A habitat, both seawater and sediment had lowest mean observed OTUs (operational taxonomic units) of 428.5 and 318.0, and highest mean values were noted in residential sediment (1255.5) and industrial-B seawater (865.0). Despite sediment in the protected site having the second-highest mean OTUs (1240.0), seawater had the second-lowest by 345 OTUs. The dominant prokaryotes were Proteobacteria, Bacteroidota, Campylobacterota, Firmicutes, and Actinobacteriota, accounting for 82.8 % of the total community load. Sediments were enriched with <em>Marinobacter, Sulfurimonas, Thiomicrorhabdus, Sulfurovum,</em> and <em>Rheinheimera</em> genera, while seawaters were dominated by genera <em>Pseudomonas, Shewanella, Bacillus, Rheinheimera,</em> and <em>Flavobacterium</em>, respectively. Key sediment parameters having strong interplay with dominant taxa were soil texture, EC, and OM, and key seawater parameters included salinity, BOD₅, and PO₄^3-. PCA identified the influence of these environmental parameters on specific prokaryotic communities. High pollution load index of Industrial-A site may have contributed to lowest prokaryotic diversity, suggesting substantial influence of heavy metals. The current study revealed that prokaryotic composition was sensitive to unique environmental properties induced by local human-driven activities. Hence, all findings will contribute a strong theoretical basis for future coastal ecosystem quality assessments.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"90 ","pages":"Article 104498"},"PeriodicalIF":2.4,"publicationDate":"2025-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145105524","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":"Comparative assessment of nutritional quality and ecotoxicological biomarkers in Paphia textile clams from the coastal areas in Egypt","authors":"Amel H. El-Gendy ,&nbsp;Md. Mushfiqur Rahman ,&nbsp;Arnob Ghosh ,&nbsp;Mir Shariful Islam ,&nbsp;Abdullah A. Alkahtane ,&nbsp;Saleh Al Farraj ,&nbsp;Md. Habibullah-Al-Mamun","doi":"10.1016/j.rsma.2025.104495","DOIUrl":"10.1016/j.rsma.2025.104495","url":null,"abstract":"<div><div><em>Paphia textile</em>, a commercially vital clam species in Egyptian coastal waters, serves as both a nutritional resource and bioindicator of marine pollution. This study evaluates the spatial variability of proximate composition, fatty acid profiles, elemental and heavy metal concentrations (Cu, Zn, Pb, Cd, Hg), oxidative stress biomarkers (SOD, CAT, GPx, MDA, MT), and genotoxicity (comet assay) in <em>P. textile</em> from Ismailia and Alexandria. Clams from Ismailia exhibited superior nutritional value, with higher protein (0.49 ± 0.06 g/g; p &lt; 0.01) and carbohydrate (0.32 ± 0.04 g/g; p &lt; 0.01) content, alongside significant (p &lt; 0.01) elevated antioxidant enzyme activity (SOD: 3.81 ± 0.43 U/mg; CAT: 2.85 ± 0.68 U/mg; GPx: 59.71 ± 5.09 U/mg), reflecting lower environmental stress. In contrast, Alexandria samples showed heightened oxidative damage (p &lt; 0.05), marked by elevated MDA (41.02 ± 2.91 nmol/mg protein), MT (208.42 ± 9.45 µg/g), and significant DNA damage (tail DNA%: 7.8 %; tail moment: 4.8 units). Although health risk indices were below the threshold limit (THQ &lt; 1; TCR &lt; 1 ×10⁻⁶), heavy metal concentrations, particularly Pb (0.13 ± 0.07 µg/g) and Hg (0.065 ± 0.025 µg/g), were higher in Alexandria highlighting greater dietary hazards despite containing beneficial fatty acids like DHA. Overall, clams from Ismailia demonstrated superior nutritional value and lower health risk, while Alexandria samples reflected greater environmental contamination. These findings highlight the need for continuous environmental monitoring and reinforce <em>Paphia textile</em> as an effective bioindicator for coastal pollution and food safety assessment.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"90 ","pages":"Article 104495"},"PeriodicalIF":2.4,"publicationDate":"2025-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145060444","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":"Methods for monitoring abalone Young-of-the-Year in the Japan Sea: Habitat utilization and depth distribution of Haliotis species","authors":"Yukio Matsumoto ,&nbsp;Hideki Takami ,&nbsp;Norio Shirafuji ,&nbsp;Yoshiaki Shinohara ,&nbsp;Tomofumi Seta ,&nbsp;Tomokazu Nishigaki","doi":"10.1016/j.rsma.2025.104489","DOIUrl":"10.1016/j.rsma.2025.104489","url":null,"abstract":"<div><div>The four abalone species <em>Haliotis discus discus, H. madaka, H. gigantea, and H. diversicolor</em> are important fisheries resources in Japan. However, the stock abundance of these species has declined. Fluctuations in abalone young-of-the-year (YOY) stocks may significantly influence adult stock abundance. Monitoring methods for YOY are proposed which clarify habitat shifts associated with growth, particularly in <em>H. discus discus</em> and <em>H. diversicolor.</em> While only partial trends could be inferred for <em>H. madaka</em> and <em>H. gigantea</em>. For all four species, YOY were frequently observed in gaps between rocks or beneath sea urchins in these gaps. In <em>H. discus discus</em> and <em>H. diversicolor</em>, a habitat shift was observed with growth, transitioning from cryptic habitats (e.g., rock gaps and areas under sea urchins) to more exposed habitats. The depths at which YOY were found varied each year. However, <em>H. discus discus</em> and <em>H. diversicolor</em> were found in shallower waters than <em>H. madaka</em> and <em>H. gigantea</em>; the former two species appeared to migrate from deeper to shallower areas as they grew. These findings provide essential insights for improving abalone YOY survey methods. Additionally, it was recognized that, since catch-per-unit-effort trends varied among the four species, precise YOY species identification is crucial for effective monitoring.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"91 ","pages":"Article 104489"},"PeriodicalIF":2.4,"publicationDate":"2025-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145108004","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}