Estuarine Coastal and Shelf Science最新文献

{"title":"Reef-scale variation in larval supply and settlement: validating Lagrangian dispersal predictions with observations of coral larvae","authors":"Robert A.B. Mason ,&nbsp;Clothilde Langlais ,&nbsp;Julian Uribe-Palomino ,&nbsp;Mark Tonks ,&nbsp;Frank Coman ,&nbsp;Severine Choukroun ,&nbsp;Javier Porobic ,&nbsp;Christopher Doropoulos","doi":"10.1016/j.ecss.2025.109506","DOIUrl":"10.1016/j.ecss.2025.109506","url":null,"abstract":"<div><div>Population persistence and recovery in marine systems is driven by larval dispersal in the water column, generating ecological connectivity between the natal and settlement locations. Connectivity modelling is commonly utilised for the spatial planning of marine protected areas and, more recently, for the prioritisation of restoration interventions. Here, we conducted field experiments to validate the spatial patterns and rates of larval arrival as simulated by a high-resolution connectivity model (∼300 m resolution), using complementary spatial and temporal sampling of coral larvae and newly settled recruits around a cluster of offshore coral reefs. At the within-reef scale, Lagrangian dispersal modelling demonstrated only a fair performance at predicting observed spatial patterns of larval arrival and settlement, at best. However, at the reef cluster level, hydrodynamically-driven interannual variations in larval supply were well correlated with observed interannual variations. Combined, the model results resolve empirical observations for the temporal (inter-annual) and spatial scales relevant to meta-population dynamics (1–10s of km's). At the finer spatial scales of resolution (&gt;1/10 ha to &lt;10 ha), relevant to current restoration interventions, skill at predicting larval density is poor whilst skill at predicting larval settlement is fair. Overall, our findings identify the need for a model validation framework that considers the scales of physical processes resolved by the hydrodynamic modelling, spatial-temporal variability in the propagule populations being measured, the error tolerance for how the outputs of model simulations are being utilised (theoretical <em>versus</em> operational), and the complementary use of modelling and field sampling for different scales of application.</div></div>","PeriodicalId":50497,"journal":{"name":"Estuarine Coastal and Shelf Science","volume":"326 ","pages":"Article 109506"},"PeriodicalIF":2.6,"publicationDate":"2025-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145019643","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Coastal zones of the Baltic Sea in the Anthropocene: Current state and the impact of climate change","authors":"Maren Voss ,&nbsp;Peter Holtermann ,&nbsp;Soeren Ahmerkamp ,&nbsp;Damian Leonardo Arévalo Martínez ,&nbsp;Bronwyn Cahill ,&nbsp;Manita Chouksey ,&nbsp;Joachim W. Dippner ,&nbsp;Jörg Dutz ,&nbsp;Peter Feldens ,&nbsp;Jacob Geersen ,&nbsp;Kaja Gentsch ,&nbsp;Mayya Gogina ,&nbsp;Daniel Herlemann ,&nbsp;Jan Henkel ,&nbsp;Marion Kanwischer ,&nbsp;Bennet Krebs ,&nbsp;Anke Kremp ,&nbsp;Anju Malissery ,&nbsp;Robert Mars ,&nbsp;Jann Müller ,&nbsp;Oliver Zielinski","doi":"10.1016/j.ecss.2025.109504","DOIUrl":"10.1016/j.ecss.2025.109504","url":null,"abstract":"<div><div>Coastal zones and estuaries are highly dynamic marine systems subject to anthropogenic pressure and to climate-related changes. The coastal zone of the Baltic Sea, shaped by extreme seasonality, strong bentho-pelagic coupling, and intense human use, represents a unique model system to study these interactions under accelerating climate change. While extensive research has been conducted on warming, eutrophication, and large scale hypoxia in the region, critical gaps remain in understanding how physical forcing, sediment type, and benthic–pelagic coupling control nutrient turnover, primary production, seed and egg bank dynamics, and the emission of climate-relevant gases under rapidly changing dynamic conditions. The Baltic Sea, with 26 % of its area shallower than 15 m, harbor mostly sandy sediments along the southern coast, but the coastal nutrient filter remains poorly investigated because element fluxes are mostly controlled by advection. Sediments are home for phytoplankton resting stages, but the contribution of seed germination to the development of phytoplankton blooms is unknown. The resting eggs of zooplankton are also deposited in the sediment, but the timing of zooplankton and fish development in spring and the impact of progressive warming are poorly understood. Decreases in salinity strongly influence macrobenthos in the Baltic Sea, whereas increased eutrophication favors the growth of opportunistic species. Finally, coastal darkening is discussed, as it affects marine life in ways that are difficult to assess. Future studies of coastal zones will benefit from technical innovations like mooring systems that transmits data immediately to the shore and uses drones to aid in sampling along coastlines. This review synthesizes current knowledge on the state and functioning of the Baltic coastal zone, highlighting novel insights into the role of permeable sandy sediments as nutrient cycling hotspots. We identify key uncertainties arising from the high spatio-temporal variability of these systems, which limit the predictive capacity of existing models. Only by combining novel approaches we can improve projections of climate-change impacts, and provide a robust scientific basis for the management and protection of vulnerable coastal ecosystems. Accordingly, the measures that will enable stakeholders and politicians to improve the protection of coastal areas remain to be developed.</div></div>","PeriodicalId":50497,"journal":{"name":"Estuarine Coastal and Shelf Science","volume":"326 ","pages":"Article 109504"},"PeriodicalIF":2.6,"publicationDate":"2025-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144919833","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Length-weight relationship of the bony fish community inhabiting the southwest Atlantic coast, with emphasis on commercially important species","authors":"Ailin Monti ,&nbsp;Claudio Ruarte ,&nbsp;Paula Orlando ,&nbsp;Mariano Elisio","doi":"10.1016/j.ecss.2025.109508","DOIUrl":"10.1016/j.ecss.2025.109508","url":null,"abstract":"<div><div>Knowledge of the parameters of the fish length-weight relationship model (LWR), <span><math><mrow><mi>W</mi><mi>e</mi><mi>i</mi><mi>g</mi><mi>h</mi><mi>t</mi><mo>=</mo><mi>a</mi><mspace></mspace><mo>∗</mo><mspace></mspace><mi>L</mi><mi>e</mi><mi>n</mi><mi>g</mi><mi>h</mi><msup><mi>t</mi><mrow><mspace></mspace><mi>b</mi></mrow></msup></mrow></math></span>, provides essential information for understanding biology and population assessments, enabling the development of conservation measures and fisheries management. This study estimated LWR parameters and described the growth type of 46 bony fish species (from 28 families and 43 genera) caught by bottom trawl in the fishery assessment surveys carried out by the National Institute of Fisheries Research and Development between 1981 and 2022 on the southwest Atlantic coast between 34° and 42°S, &lt;50 m depth. The LWR parameters (a and b) were estimated by fitting linear regression models to the total length and weight data after log transformation. Growth type was assessed by statistically comparing the parameter b with a value of 3 (isometric growth), and considering a negative or positive allometric growth when b &lt; 3 or b &gt; 3, respectively. Model fit was statistically significant for all species (R² = 0.83–0.99). Half of the species evaluated exhibited negative allometric growth, 35 % positive allometric, and 15 % isometric growth. Among the 24 commercially important species, nearly half showed positive allometric growth. Thus, most of these bony fishes from the southwest Atlantic coast appear to fail the cube law of isometric growth. This study publishes for the first time information on this important biological trait for 42 species along the assessed region, four of which had no data available worldwide, and updates the available information for a further four species, improving knowledge for future biological and ecological assessments of their populations.</div></div>","PeriodicalId":50497,"journal":{"name":"Estuarine Coastal and Shelf Science","volume":"325 ","pages":"Article 109508"},"PeriodicalIF":2.6,"publicationDate":"2025-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144886372","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Coastal fauna under threat from roadkills: A case study in southeastern Brazil","authors":"Camyla Freitas Viana ,&nbsp;Eduardo Bulhões ,&nbsp;Danilo Freitas Rangel ,&nbsp;Ilana Rosental Zalmon ,&nbsp;Leonardo Lopes Costa","doi":"10.1016/j.ecss.2025.109507","DOIUrl":"10.1016/j.ecss.2025.109507","url":null,"abstract":"<div><div>Animal collisions serve as key indicators of the impacts of roads on biodiversity. However, existing records and predictions of roadkill susceptibility predominantly focus on large inland roads and terrestrial species, overlooking its broader impacts on diverse ecosystems and coastal fauna. The objective of this study was to evaluate whether spatial and temporal factors influence the risk of animals being road-killed on a coastal road in Southeastern Brazil. The road was monitored from August 2021 to January 2024 over a stretch of approximately 8 km. The search for animals on the road was conducted at night using a vehicle traveling at ∼20 km/h. Each animal encounter was georeferenced to measure satellite-based variables including the level of urbanization, artificial light, shoreline tree coverage, beach width, coastline retreat tendency, tide range, air temperature, precipitation, and wave height. A total of 250 animals were found, including nine opossums, six birds, three snakes, one bat, 47 sea turtle hatchlings, and 184 ghost crabs. According to the Generalized Linear Model with binomial distribution, the risk of ghost crabs being road-killed was significantly higher in areas more affected by erosion, and during storm wave events. These results provide evidence that coastal roadkills are intensified by the loss of refuge habitats, a key characteristic of the coastal squeeze phenomenon. To minimize wildlife collisions on coastal roads, it is recommended to close roads during storms mainly in areas affected by erosion, build wildlife crossings, install signs indicating the presence of fauna, and implement public awareness programs in the region.</div></div>","PeriodicalId":50497,"journal":{"name":"Estuarine Coastal and Shelf Science","volume":"325 ","pages":"Article 109507"},"PeriodicalIF":2.6,"publicationDate":"2025-08-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144886370","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"RNA-seq and qPCR analyses of food conditions and their influence on gene expression in the Manila clam (Ruditapes philippinarum)","authors":"Nariaki Inoue ,&nbsp;Natsumi Sano ,&nbsp;Shouji Houki","doi":"10.1016/j.ecss.2025.109505","DOIUrl":"10.1016/j.ecss.2025.109505","url":null,"abstract":"<div><div>An understanding of the food conditions to which clams are exposed and the associated differences in physiologyical conditions is important for identifying the mechanisms that affect resource fluctuations. We performed RNA-seq and quantitative PCR with juveniles reared under two different feeding conditions: non-feeding (N) and feeding (F). RNA-seq with 18 libraries contained a total of 167733 unigenes of which 6093 were determined to be differentially expressed genes (DEGs) in the comparison of N and F on days 3, 5 and 20 during the rearing period. From the pathway analysis of DEGs, ECM-receptor interaction and Focal adhesion pathways were well enriched, and they are characteristic pathways that respond to changes in food conditions. From changes in the defensin, ependymin-related protein-1, heat shock protein 22 and thioredoxin expression patterns, we could categorize the physiological conditions of juveniles in starvation into short-term starvation (1–3 days), during which genes expression in the non-feeding (N) relative to the feeding (F) declined rapidly; medium-term starvation (3–15 days), during which genes expression then increased rapidly; and long-term starvation (15 days and longer), during which genes expression declined again.</div></div>","PeriodicalId":50497,"journal":{"name":"Estuarine Coastal and Shelf Science","volume":"325 ","pages":"Article 109505"},"PeriodicalIF":2.6,"publicationDate":"2025-08-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144879142","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Transitional habitats and transformative dialogues: Use of the resist-accept-direct (RAD) framework to identify tidal freshwater forested wetland management actions","authors":"Michelle Moorman ,&nbsp;Ken W. Krauss ,&nbsp;Brita J. Jessen ,&nbsp;Dawn R. Magness ,&nbsp;Jennifer L. Wilkening ,&nbsp;Ansley V. Williamson ,&nbsp;Craig Sasser","doi":"10.1016/j.ecss.2025.109501","DOIUrl":"10.1016/j.ecss.2025.109501","url":null,"abstract":"<div><div>Tidal freshwater forested wetlands (TFFWs) are ecologically and culturally valuable ecosystems increasingly threatened by sea level rise and land use change. South Carolina contains the largest extent of TFFWs in the United States, including 36,530 ha in the lower Waccamaw River Basin. As these systems undergo ecological transformation, new tools are needed to support adaptive management under novel conditions. The Resist–Accept–Direct (RAD) framework provides a structured approach for exploring a full range of potential responses to environmental change.</div><div>We present a case study of applying RAD through a facilitated one-day workshop involving natural and social scientists, land managers, and local decision-makers that occurred as part of a 3 day conference on TFFWs in March of 2024. Participants reviewed plausible ecological futures and engaged in structured brainstorming to develop a RAD-aligned menu of management actions linked to shared goals and objectives. Six times more actions were identified post-workshop compared to pre-workshop inputs, indicating a substantial expansion of perceived decision space and available alternatives.</div><div>This study demonstrates that RAD menu development is a practical tool for fostering deliberative engagement in coastal wetland systems. When supported by preparatory information and inclusive facilitation, even short workshops can generate diverse, actionable strategies for managing ecological transformation. These findings offer a transferable model for applying RAD across estuarine and coastal landscapes facing accelerating change.</div></div>","PeriodicalId":50497,"journal":{"name":"Estuarine Coastal and Shelf Science","volume":"325 ","pages":"Article 109501"},"PeriodicalIF":2.6,"publicationDate":"2025-08-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144852316","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Wildlife of tidal forested wetlands in the southeastern Atlantic United States","authors":"James T. Anderson ,&nbsp;Andrew P. Hopkins ,&nbsp;Crystal Anderson ,&nbsp;Miriam Boucher ,&nbsp;Rene Brown ,&nbsp;Aruã de Castro ,&nbsp;Sindupa De Silva ,&nbsp;Robert M. Greco ,&nbsp;Jordan E. McCall ,&nbsp;Oluwatobi Emmanuel Olaniyi ,&nbsp;Christopher Pettengill ,&nbsp;Akshit R. Suthar ,&nbsp;Cindy L. Von Haugg","doi":"10.1016/j.ecss.2025.109500","DOIUrl":"10.1016/j.ecss.2025.109500","url":null,"abstract":"<div><div>Tidal forested wetlands combine hardwood forest structure with the tidal regimes of more coastally associated wetlands. While they are appreciated for their diversity, little is known about their dynamics and how different processes shape wildlife communities. Their ephemeral nature and heterogeneity facilitate habitat refuges for numerous species ranging from waterfowl to reptiles and mammals. These wetlands support species that fulfill numerous ecological roles, ranging from nutrient transport to ecosystem engineering. However, the ecosystem also functions to shape the species composition, with factors such as saltwater infiltration creating ghost forests and increasing available habitat. While inundation and saltwater intrusion are factors in tidal forested wetlands, climate change is increasing these factors beyond recent historic levels. While research efforts are growing, more work must be done to understand how tidal forested wetlands and their species respond and adapt to climate change.</div></div>","PeriodicalId":50497,"journal":{"name":"Estuarine Coastal and Shelf Science","volume":"325 ","pages":"Article 109500"},"PeriodicalIF":2.6,"publicationDate":"2025-08-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144886371","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Radium isotopes trace cross-shelf nutrient transport in a marginal sea","authors":"Aprajita S. Tomer ,&nbsp;Tristan McKenzie ,&nbsp;Claudia Majtényi-Hill ,&nbsp;Tibaud Cardis ,&nbsp;Linnea Henriksson ,&nbsp;Per O.J. Hall ,&nbsp;Beata Szymczycha ,&nbsp;Nico Mitschke ,&nbsp;Isaac R. Santos","doi":"10.1016/j.ecss.2025.109502","DOIUrl":"10.1016/j.ecss.2025.109502","url":null,"abstract":"<div><div>Nearshore coastal zones play a critical role modulating terrestrial nutrient transport into the ocean. While nutrient dynamics of marginal seas like the Baltic Sea are well documented, they are predominantly based on riverine inputs, overlooking the biogeochemical transformation and exchange of nutrients beyond the estuarine filter. Here, we use short-lived radium isotopes to investigate cross shelf nutrient transport along 14 transects, spatially distributed across 12 locations along the Baltic Sea coastline. The radium tracer approach revealed a horizontal eddy diffusivity rate of (3.9 ± 1.1) x 10⁶ m² day⁻¹ and nearshore water residence time of 7.6 ± 4.5 days. Cross-shelf nutrient loads extrapolated along the 8000 km coastline were 8.2 ± 2.9 kt Si day⁻¹ for silicate, 0.9 ± 0.5 kt N day⁻¹ for dissolved inorganic nitrogen (DIN), and 0.1 ± 0.02 kt P day⁻¹ for phosphate. DIN loads were 4.5 times higher than average historical river-derived loads for September. Phosphate inputs were 20 % higher, while silicate transport rates were 57 % lower than the corresponding historical river loads. While comparisons between our radium-derived cross-shelf fluxes with river loads create perspective, they should be seen with care due to potential spatial and temporal biases. Overall, these findings illustrate the use of radium as a tracer of terrestrial inputs and underscore the need to integrate shelf-scale processes beyond the estuarine filter into coastal nutrient assessments.</div></div>","PeriodicalId":50497,"journal":{"name":"Estuarine Coastal and Shelf Science","volume":"325 ","pages":"Article 109502"},"PeriodicalIF":2.6,"publicationDate":"2025-08-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144863291","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Multiscale variation in the burrow typology and abundance of Ucides cordatus across Atlantic mangroves: effects of time, space, and climate","authors":"Marcelo A.A. Pinheiro ,&nbsp;Alison C. Wunderlich ,&nbsp;Sérgio S. Rocha ,&nbsp;Marcio C.A. João ,&nbsp;Esli E.D. Mosna ,&nbsp;Salise B. Martins ,&nbsp;Setuko Masunari","doi":"10.1016/j.ecss.2025.109503","DOIUrl":"10.1016/j.ecss.2025.109503","url":null,"abstract":"<div><div>Understanding ecological processes across spatial and temporal scales is crucial for interpreting population dynamics and guiding conservation efforts. However, multiscale influences on decapod crustacean populations remain underexplored. We investigated the variability in <em>Ucides cordatus</em> burrow typologies across two protected Brazilian mangrove ecosystems: Juréia-Itatins Ecological Station (JIES) and Superagui National Park (SNP). Sampling involved 120 quadrats (5 × 5 m each), with five quadrats allocated to each mangrove zone (fringe and apicum) at both conservation units, during summer and winter seasons over three consecutive years (2016–2018). Generalised linear models tested the effects of year, season, site, and tidal zone on the abundance of five burrow types: SGL (single-opening), MLT (multi-opening), OPE (sum of SGL and MLT), CLO (closed), and ABD (abandoned). We observed marked interannual and seasonal variability, especially under climatic anomalies, along with spatial contrasts driven by tidal flooding patterns and microhabitat structure. Burrow types reflected distinct functional phases: SGL and MLT were linked to active behaviour and responded sharply to environmental variation; CLO was associated with reproduction or moulting; ABD indicated environmental stress or recolonisation. Fringe zones exhibited greater variability and reduced open burrow abundance under stressful conditions. Integrating burrow typologies with spatiotemporal factors proved an effective, non-invasive approach for detecting ecological shifts and assessing habitat quality. Our findings reinforce the role of <em>U. cordatus</em> as a bioindicator species and support the use of burrow-based metrics in the long-term monitoring and conservation of mangrove ecosystems facing increasing climatic and anthropogenic pressures.</div></div>","PeriodicalId":50497,"journal":{"name":"Estuarine Coastal and Shelf Science","volume":"326 ","pages":"Article 109503"},"PeriodicalIF":2.6,"publicationDate":"2025-08-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144902446","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Ecological and physiological role of the estuary in sexual maturation and spawning in the amphidromous goby Rhinogobius similis","authors":"Yumeki Oto ,&nbsp;Shunsaku Sato ,&nbsp;Kazuha Takai ,&nbsp;Noritaka Mochioka","doi":"10.1016/j.ecss.2025.109499","DOIUrl":"10.1016/j.ecss.2025.109499","url":null,"abstract":"<div><div>Estuaries are important habitats not only for estuarine-resident species, but also for temporary inhabitants, such as diadromous species that migrate between marine and freshwater environments. However, the role of estuaries in the reproductive events of diadromous fish remains largely unknown. To address this gap, this study focused on an amphidromous (a diadromy subtype) goby species, <em>Rhinogobius similis</em>, which frequently spawns in estuaries in Japan, although its primary adult habitat appears to be in freshwater. This study investigated the degree of dependence on estuaries as spawning grounds and the effects of salinity on reproductive physiology in this species through field surveys and laboratory experiments. Otolith microchemical analysis combined with the dynamic time warping method revealed that otoliths of 29 out of 40 reproductive adults collected from an estuary (northern Kyushu, Japan) exhibited consistently low strontium/calcium (Sr/Ca) ratios throughout their juvenile and adult stages, suggesting that these individuals spent most of their time in freshwater prior to collection. A laboratory rearing experiment showed that testis development was greater in brackish water condition (salinity 10) than in freshwater, with no significant effect on ovary development. Consistently, testis development of the reproductive adults from the river estuary was marginally positively correlated with otolith Sr/Ca ratios (i.e., the degree of estuarine dependence). These results suggest that salinity partly influences gonadal development in <em>R. similis</em>. Overall, the series of surveys and experiments conducted in this study highlight the importance of estuaries as habitats for sexual maturation and spawning in this amphidromous goby species.</div></div>","PeriodicalId":50497,"journal":{"name":"Estuarine Coastal and Shelf Science","volume":"326 ","pages":"Article 109499"},"PeriodicalIF":2.6,"publicationDate":"2025-08-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144893373","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}