Regional Studies in Marine Science最新文献

{"title":"DNA methylation and seasonal environmental effects on growth and reproduction in the mysid mesopodopsis slabberi","authors":"Ana Filipa Oliveira ,&nbsp;Joana Pereira ,&nbsp;Sónia Cotrim Marques ,&nbsp;Albano Pinto ,&nbsp;Ulisses M. Azeiteiro","doi":"10.1016/j.rsma.2026.105018","DOIUrl":"10.1016/j.rsma.2026.105018","url":null,"abstract":"<div><div>The high sensitivity to environmental variation makes mysid species effective bioindicators for assessing climate change impacts. Seasonal changes in temperature and salinity can affect their growth, body size, reproduction, and development time. Mysids are ecologically significant and serve as model organisms in environmental and ecotoxicological studies due to their advantageous biological traits. Emerging evidence also suggests that epigenetic mechanisms may mediate their responses to environmental stressors. This study examined seasonal and environmental influences on the morphology, reproduction, and epigenetic responses of <em>Mesopodopsis slabberi.</em> Seasonal analysis revealed significant differences in female body length, brood size, and newborn length, with larger females and offspring observed during winter, although brood size was smaller. Correlation analysis indicated a trade-off between offspring size and number, with larger females producing fewer but larger offspring. Morphological measurements showed strong positive correlations between body length and appendage dimensions. Experiments under different temperature and salinity conditions revealed that temperature significantly affected body length in the 3 mm size class, while salinity significantly influenced the 4 mm size class under specific conditions. Regarding epigenetics, this study reports the first quantification of DNA methylation in <em>M. slabberi</em>, revealing global levels ranging from 0.05% to 1.13% of the genome. Although no statistically significant effects of sex, temperature, or salinity on methylation were observed, variations across treatments suggest potential for environmentally mediated epigenetic responses. Understanding these dynamics is crucial, as climate-induced shifts in temperature and salinity may strongly affect the life cycles, morphological and epigenetic responses of estuarine mysids, potentially leading to cascading ecological impacts.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"97 ","pages":"Article 105018"},"PeriodicalIF":2.4,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147798246","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":"Diversity, growth and toxicity of the diatom genera Pseudo-nitzschia and Nitzschia in the Southern Mediterranean shellfish areas","authors":"Sondes Melliti Ben Garali ,&nbsp;Inès Sahraoui ,&nbsp;Nina Lundholm ,&nbsp;Abdessalem Kouki ,&nbsp;Pablo de la Iglesia ,&nbsp;Jorge Diogène ,&nbsp;Karl B. Andree ,&nbsp;Margarita Fernández-Tejedor ,&nbsp;Kaouther Mejri Kousri ,&nbsp;Asma Sakka Hlaili","doi":"10.1016/j.rsma.2026.105013","DOIUrl":"10.1016/j.rsma.2026.105013","url":null,"abstract":"<div><div>Diatom genera <em>Pseudo-nitzschia</em> and <em>Nitzschia</em> include toxic species which produce domoic acid (DA), a neurotoxin causative of amnesic shellfish poisoning. The proliferation of these species constitutes a real environmental and health risk. Therefore, the identification of toxic species, particularly in aquaculture areas, are increasingly essential for toxin monitoring and decisions regarding the exploitation of shellfish. The study investigated the diversity of theses diatom genera at important shellfish culture areas in the SW Mediterranean Sea (Lagoon and Bay of Bizerte, North of Tunisia). The growth of isolated strains and their ability to produce DA were assessed in batch culture experiments. The study provides a detailed description of six species (<em>Nitzschia bizertensis</em>, <em>Pseudo-nitzschia calliantha, P. fryxelliana, P. hasleana, P. mannii</em> and <em>P.</em> cff<em>. seriata</em>), some of which (<em>N. bizertensis</em>, <em>P. hasleana</em> and <em>P. fryxelliana</em>) are poorly documented in Mediterranean waters. These species were observed at densities varying from 3 × 10³–9.3 × 10⁵ cells L^‐1. Exponential growth rates varied from 0.34 to 0.48 d-¹ for <em>Pseudo-nitzschia</em> species, while <em>N. bizertensis</em> showed lower rates (0.27 d⁻¹). Our study gives the first report of DA production in <em>P</em>. <em>mannii</em> (1.28 ng DA L⁻¹, 0.10 fg DA cell⁻¹), using LC-MS/MS (Liquide Chromatography-tandem Mass Spectrometry). Some strains of <em>N. bizertensis</em>, <em>P. hasleana</em> and <em>P. calliantha</em> were tested positive for the DA production (1.56–7.29 ng DA L, 0.10–0.63 fg DA cell⁻¹)<em>.</em> Our results call attention to the increase in the diversity and toxicity of diatoms in Mediterranean aquaculture areas. Thus, further studies are needed to understand environmental factors affecting their distribution and toxicity.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"97 ","pages":"Article 105013"},"PeriodicalIF":2.4,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147798237","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":"Dietary composition and bioenergetic trade-offs suggest functional population structuring in Atlantic bonito (Scombridae: Sarda sarda) from the southern Black Sea","authors":"Rahşan Evren Mazlum ,&nbsp;Ömerhan Dürrani","doi":"10.1016/j.rsma.2026.105011","DOIUrl":"10.1016/j.rsma.2026.105011","url":null,"abstract":"<div><div>Recent morphometric analyses challenge the prevailing single-assessment-unit management of Atlantic bonito (<em>Sarda sarda</em>) in the southern Black Sea, identifying phenotype-based population structuring. This study integrated dietary composition, somatic condition, and growth allometry from a synchronised assessment of overwintering ecology across the southern Black Sea (Western: Istanbul; Middle: Sinop; Eastern: Rize) to elucidate the ecological basis of this functional population structuring. The results revealed distinct functional divergence between the Western and Eastern–Middle population units. Atlantic bonito from the Western Black Sea exhibited a generalist “portfolio” strategy, maintaining a high trophic position through opportunistic predation on biomass-rich sardines and cephalopods despite the numerical dominance of zooplankton. This heterogeneous diet coincided with a lower somatic condition but pronounced positive allometric growth. In contrast, the Eastern and Middle regions formed a cohesive functional unit characterised by anchovy dietary specialisation, high somatic condition and isometric growth. A size-corrected general linear model supported functional equivalence in trophic position across all regions, indicating that despite divergent prey pathways, Atlantic bonito occupy comparable ecological roles. These findings indicate functional population structuring, challenging the assumption of ecological panmixia by distinguishing opportunistic, compensatory fish in the West from specialist, storage-oriented counterparts in the Eastern–Middle. Consequently, this structuring provides preliminary grounds for a re-evaluation of basin-wide management in favour of spatially explicit monitoring and assessment frameworks within the GFCM context.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"97 ","pages":"Article 105011"},"PeriodicalIF":2.4,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147798948","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":"Eco-epidemiological dynamics of Vibrio-associated vibriosis in freshwater fish farms: Implications for aquatic health and food safety","authors":"Rajkumar Thamarai ,&nbsp;Venkatesh Arun ,&nbsp;Venkatesan Karthick ,&nbsp;Singamoorthy Amalraj ,&nbsp;Rajkumar Prabhakaran ,&nbsp;Kalidass Subramaniam","doi":"10.1016/j.rsma.2026.105005","DOIUrl":"10.1016/j.rsma.2026.105005","url":null,"abstract":"<div><div>Vibriosis is a major constraint to aquaculture sustainability, posing risks to fish health, production efficiency, and food safety. The primary objective of this study was to elucidate the eco-epidemiological dynamics of <em>Vibrio</em>-associated infections in freshwater fish farms and evaluate their seasonal patterns concerning environmental factors. A year-long survey (January-December 2022) was conducted across 98 freshwater farms in the Tirunelveli District of southern India, comprising 1364 fish. Microbiological analysis revealed that <em>Vibrio alginolyticus</em> was the predominant species (25.37%), followed by <em>Vibrio harveyi</em> (21.75%) and <em>Vibrio parahaemolyticus</em> (21.58%). In comparison, <em>Vibrio vulnificus</em> (11.53%) was less prevalent but of notable pathogenic concern because of its invasiveness. The incidence of vibriosis exhibited pronounced seasonality, with a significantly higher prevalence during warmer months (26.32–48.12%) than during cooler months. This temporal pattern was strongly associated with environmental parameters, particularly water temperature, suggesting a critical role in pathogen proliferation and in disease progression. Overall, these findings highlight the importance of integrating eco-epidemiological surveillance with climate-responsive management strategies to mitigate the risk of disease. An improved understanding of pathogen dynamics provides a foundation for developing targeted interventions to enhance aquatic animal health and ensure food safety in freshwater aquaculture systems.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"97 ","pages":"Article 105005"},"PeriodicalIF":2.4,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147798945","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":"Appraising ecosystem damage and recovery dynamics in coastal Bangladesh following tropical cyclones using multi-temporal earth observation data","authors":"Utsav Basak,&nbsp;Sanzida Murshed,&nbsp;Md. Ashraful Islam","doi":"10.1016/j.rsma.2026.105002","DOIUrl":"10.1016/j.rsma.2026.105002","url":null,"abstract":"<div><div>Coastal ecosystems are among the most prolific natural systems on Earth, while remaining highly vulnerable to extreme climatic events. In coastal Bangladesh, recurring tropical cyclones pose a significant threat to the integrity of the ecosystems and the livelihoods of marginalized communities that depend overwhelmingly on them. This study presents an ecosystem-specific, trajectory-based assessment of cyclone-induced damage and recovery across cropland, vegetation, and mangrove ecosystems, characterizing three distinct coastal settings of Bangladesh. Using multi-temporal Earth Observation (EO) data within the Google Earth Engine (GEE) platform, we systematically assessed the impacts of Cyclone Bulbul on the Ganges Deltaic Coast), Cyclone Sidr on the Ganges and the Central Coasts, and Cyclone Mora on the Eastern Coast of Bangladesh. Damage patterns were quantified using pre- and post-cyclone Normalized Difference Vegetation Index (NDVI), while spatial clustering of damage was identified through Getis-Ord Gi* hotspot analysis. Ecosystem recovery was evaluated over short- and long-term periods relative to pre-cyclone conditions, with recovery rates quantified using Sen’s Slope analysis. Moving beyond conventional binary recovery assessments, a six-class recovery framework-<em>rapid recovery</em>, <em>slow recovery</em>, <em>emerging regrowth</em>, <em>declining recovery</em>, <em>severe degradation</em>, and <em>no change</em> was developed to capture nuanced post-cyclone ecosystem dynamics. The results indicate pronounced spatial heterogeneity: the Western coast exhibited limited damage (∼38% in cropland) with dominant regrowth (&gt;24% in cropland and &gt;86% in vegetation) whereas the Central coast experienced higher damage (&gt;62% in cropland) with substantial slow or declining recovery, particularly in cropland and mangroves. Contrarywise, the Eastern coast showed moderate damage (∼40% in vegetation and 60% in cropland) with relatively higher rapid recovery. Strong agreement between satellite-derived and ground-based observations supports the reliability of the proposed framework in assessing damage and recovery status. These findings establish a spatially explicit foundation for ecosystem conservation and restoration planning in the cyclone-prone coastal Bangladesh.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"97 ","pages":"Article 105002"},"PeriodicalIF":2.4,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147798949","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":"Distribution and taxonomic composition of leptocephali and hydrographic structure from New Zealand to the South Equatorial Current","authors":"Michael J. Miller ,&nbsp;Shun Watanabe ,&nbsp;Robert Schabetsberger ,&nbsp;Nioka Behan-Kitto ,&nbsp;Grace F. Cawley ,&nbsp;Niamh Smith ,&nbsp;Alisha M. Gill ,&nbsp;Alexandre Che-Pelicier ,&nbsp;Juliet E. Saul ,&nbsp;Abigail Sim ,&nbsp;Therese C. Miller ,&nbsp;Sajini Dissanayake ,&nbsp;Andrew L. Stewart ,&nbsp;Amandine J.M. Sabadel","doi":"10.1016/j.rsma.2026.105026","DOIUrl":"10.1016/j.rsma.2026.105026","url":null,"abstract":"<div><div>In October-November 2024, an interdisciplinary sampling survey of anguilliform leptocephalus larvae was conducted in the western South Pacific Ocean. Hydrographic measurements and net sampling using an Isaacs–Kidd Midwater Trawl (IKMT), a Rectangular Midwater Trawl (RMT) and a Multiple Opening/Closing Net and Environmental Sensing System (MOCNESS), were conducted across a broad region north and northwest of New Zealand, extending to the South Equatorial Current region. The hydrographic structure reflected the typical pattern of warmer low-latitude water with a low-salinity surface layer (Fresh Pool). Net deployments at 39 sampling stations (34 IKMT, 17 RMT, 24 MOCNESS) collected 367 leptocephali and six juvenile eels of ∼99 species from 13 families of eels and notacanths. The family Congridae was the most diverse, with ∼25 species including seven <em>Ariosoma</em> species-types. <em>Conger</em> leptocephali were widely present in the New Caledonia region, and recruitment-stage <em>Gnathophis</em> larvae were collected over the continental slope of northern New Zealand. There were also ∼21 species of Muraenidae leptocephali caught in the north, along with some larvae of other shallow water eel families (Ophichthidae, Chlopsidae, Moringuidae). The leptocephali of the mesopelagic eel families (Serrivomeridae, Nemichthyidae, Derichthyidae) were widely present at northern latitudes. Various rare types of leptocephali were also collected (<em>Scalanago lateralis</em>, <em>Congriscus</em>, Type I) and importantly, nine <em>Anguilla</em> leptocephali were found exclusively at stations within the warmer, lower-salinity Fresh Pool. Together, these results provide a broad overview of leptocephalus diversity and distribution in the western South Pacific and demonstrate the value of combining multiple trawl types for sampling across size ranges.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"97 ","pages":"Article 105026"},"PeriodicalIF":2.4,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147850476","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":"Evaluation and progression of marine heatwaves over the northwestern Indian Ocean: A comparative study using satellite and numerical model data","authors":"Akurathi Venkata Sai Chaitanya,&nbsp;Abdul Azeez Saleem,&nbsp;Muhammad Shafeeque,&nbsp;Salim Lateef,&nbsp;Mohamed Asharaf,&nbsp;Jiya Albert","doi":"10.1016/j.rsma.2026.105033","DOIUrl":"10.1016/j.rsma.2026.105033","url":null,"abstract":"<div><div>This study analyzes the spatio-temporal characteristics and drivers of marine heatwaves (MHWs) across the northwestern Indian Ocean using satellite-based observations (SAT) and high-resolution ocean model outputs from NEMO and HYCOM over the period 1994–2023. MHW events were estimated by adopting seasonally varying 90th percentile thresholds computed from three climatological baselines: 1982–2005, 1982–2023, and 1994–2023. The frequency and intensity of MHWs increased in recent years, particularly when evaluated against the colder historical baseline (1982–2005). SAT MHWs showed a strong spatial variability, with peak intensities and cumulative exposure in the northern Red Sea, western Arabian Gulf, and northern Arabian Sea (NAS). NEMO model highlighted strong warm bias over NAS (0.28) and Red Sea (∼0.26) compared to Arabian Gulf (∼0.1). However, HYCOM exhibited a weak-to-moderate warm bias over all the regions (0.03–0.13)except NAS, which displayed moderate cold bias (0.15), leading to overestimation of MHW events, particularly in the NEMO dataset. Detailed analysis of major MHW years highlighted local dynamics such as anomalous net shortwave heat fluxes, reduced wind-driven mixing and increased ocean heat content contribute to MHWs persistence. The correlation matrix of MHWs frequency and climate modes showed a strong relation with Atlantic multidecadal oscillation. The negative long-term trends for chlorophyll-a and net primary production, coinciding with increasing MHW trends. Overall, this study noted that HYCOM and NEMO were able to capture the MHWs with slight uncertainty, especially over the NAS and the southern Red Sea, which could be due to the difference in surface forcing. This also highlights the importance of developing and testing regional ocean-biological models to better understand the MHWs and their impacts.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"97 ","pages":"Article 105033"},"PeriodicalIF":2.4,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147798189","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":"Machine learning-based prediction of multispecies fisheries catch in relation to environmental factors along the southern coast of Korea","authors":"Onyu Ha ,&nbsp;Da Yun Kwon,&nbsp;Seungkwan Hong","doi":"10.1016/j.rsma.2026.105036","DOIUrl":"10.1016/j.rsma.2026.105036","url":null,"abstract":"<div><div>Climate-driven shifts in marine conditions along the southern coast of Korea have become increasingly evident, while the combined influence of long-term warming and short-term physical variability on multispecies fisheries catch dynamics remains insufficiently resolved. This study integrates meteorological, oceanographic, red tide, and fisheries catch records from 1990 to 2023 and employs three machine learning approaches including Support Vector Regression, Random Forest, and eXtreme Gradient Boosting, to quantitatively evaluate the relationship between environment and fisheries catch. SHapley Additive exPlanations (SHAP) were used to identify the contributions of individual environmental predictors and assess how sea surface temperature (SST) and other interacting factors contribute to fisheries catch variability. Analysis revealed that SST acts as a persistent background factor shaping species-specific habitat suitability. In contrast, atmospheric and physical variables, including wind speed, air pressure, and relative humidity, affect fisheries production more immediately through changes in water-column structure, mixing intensity, and nutrient dynamics. The SHAP contributions indicate that interannual fisheries catch variability is influenced by a low-frequency warming signal and high-frequency atmospheric–oceanic physical factors. Red tide indicators exhibited event-driven rather than continuous effects, and species displayed heterogeneous response patterns. Overall, the results indicate that fisheries productivity in the southern Korean coastal ecosystem is jointly structured by gradual climatic trends and short-term environmental fluctuations. The integrated data–ML–explainability framework presented here clarifies how environmental variability shapes regional fisheries production and offers a basis for developing climate-responsive, region-specific management strategies.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"97 ","pages":"Article 105036"},"PeriodicalIF":2.4,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147850469","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":"Sustainable catches? A demographic assessment of exploitation levels of seven shark species caught in Ecuador","authors":"Diego Mejía ,&nbsp;Gabriel M.S. Vianna ,&nbsp;Pelayo Salinas-de-León ,&nbsp;Felipe Galván-Magaña ,&nbsp;Jesús Briones-Mendoza ,&nbsp;Carlos Robalino-Mejía","doi":"10.1016/j.rsma.2026.105004","DOIUrl":"10.1016/j.rsma.2026.105004","url":null,"abstract":"<div><div>There is growing concern regarding the status of sharks in Ecuador due to intense exploitation. We applied a stochastic age-structured model based on a Leslie matrix to assess the population status of seven shark species captured in Ecuadorian fisheries, incorporating species-specific life-history parameters. Our results indicate that under a no-fishing scenario, all assessed species exhibited population growth (<em>λ</em> &gt; 1 year⁻¹). In contrast, under current fishing mortality levels, one of the seven species maintained population growth (<em>Prionace glauca</em>; <em>λ</em> &gt; 1 year^<em>-</em>1), one remained stable (<em>Mustelus henlei</em>; <em>λ</em> ≈ 1 year⁻¹), and five showed population decline (<em>Alopias pelagicus, A. superciliosus, Carcharhinus falciformis, Isurus oxyrinchus, M. lunulatus</em>; <em>λ</em> &lt; 1 year⁻¹). Furthermore, these five species are experiencing excessive fishing mortality, with current levels surpassing those needed to maintain stable populations by over 67%. These results indicate that most heavily-fished shark species in Ecuador are overexploited and cannot currently support sustainable catches under current fishing pressure. Therefore, management and conservation measures are immediately required for these species in Ecuador. Recommended actions include reducing fishing mortality, establishing minimum catch size limits above mean size at maturity, protecting pregnant females, and implementing seasonal closures during reproductive periods, as suggested by the management scenario simulations and elasticity analyses conducted in this study. Finally, the study discusses the implications of these management measures for shark conservation in Ecuador, highlighting how species-specific vulnerabilities and population trends can guide more sustainable and context-appropriate fisheries management.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"97 ","pages":"Article 105004"},"PeriodicalIF":2.4,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147850472","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":"Projection of distribution shift for Pacific saury (Cololabis saira) in the Northwestern Pacific Ocean under climate change","authors":"Zi Yang ,&nbsp;Simeng Li ,&nbsp;Xiaoxue Liu ,&nbsp;Libin Dai ,&nbsp;Jie Cao ,&nbsp;Siquan Tian","doi":"10.1016/j.rsma.2026.105021","DOIUrl":"10.1016/j.rsma.2026.105021","url":null,"abstract":"<div><div>Pacific saury (<em>Cololabis saira</em>) is a commercially and ecologically important pelagic species in the Northwestern Pacific Ocean. Over the past decade, its spatial distribution has shown a distinct northeastward shift, which may introduce significant spatial uncertainty into stock assessment and fisheries management by altering the spatial overlap between fish stocks and fishing effort. In this study, the spatial dynamics of this species under future climate scenarios (SSP126, SSP245, SSP585) were projected using the sdmTMB modeling framework. The model was developed using catch per unit effort (CPUE) data collected by Chinese stick-held dip net fishing fleets from 2013 to 2023, together with key environmental variables, including sea surface temperature (SST) and mixed layer depth (MLD). Spatial random fields were incorporated to account for unexplained spatial heterogeneity. The results showed that MLD emerged as a dominant driver of CPUE, with predicted CPUE peaking at a depth of approximately 30 m. SST also exerted a significant influence, showing a gradual decline in CPUE across the range of 8–20°C. While monthly variation remained similar across scenarios from 2013 to 2023, the spatial distribution patterns differed. Future projections under different scenarios revealed similar interannual distribution trends, with marked variation during June to September. Under SSP126, the center of gravity shifted toward a more southeastern position; under SSP245, it showed large east–west swings; under SSP585, it exhibited strong south-north oscillations after 2040. Sensitivity tests and core distribution analysis confirm these spatial signals are robust and synchronized. These projections provide mechanistic insights into how climate change may reshape the spatial dynamics of Pacific saury, underscoring the need for spatially explicit adaptive fisheries management strategies in a warming ocean.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"97 ","pages":"Article 105021"},"PeriodicalIF":2.4,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147798186","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}