Fisheries ResearchPub Date : 2025-05-28DOI: 10.1016/j.fishres.2025.107414
Stephen A. Arnott , Noelle A. Olsen , Linus O. Stoltz , N. David Bethoney
{"title":"Spatiotemporal variation in the reproductive dynamics of female American lobsters, Homarus americanus, on the northeastern continental shelf of the United States","authors":"Stephen A. Arnott , Noelle A. Olsen , Linus O. Stoltz , N. David Bethoney","doi":"10.1016/j.fishres.2025.107414","DOIUrl":"10.1016/j.fishres.2025.107414","url":null,"abstract":"<div><div>The American lobster, <em>Homarus americanus</em>, fishery in the United States occurs along the northeastern continental shelf. It is managed as two biological stock units – the Southern New England stock and the Gulf of Maine / Georges Bank stock. Recruitment has declined over the last decade, but there is a lack of broad-scale and high-resolution information on spatiotemporal variation in female reproductive traits, especially in offshore waters. This study addressed this issue using geolocated biological data sampled over an eleven-year period by the Commercial Fisheries Research Foundation’s Lobster and Jonah Crab Research Fleet. We detected significant heterogeneity in the spatial distribution of female lobsters, and in the spatial distribution and phenological variations in ovigerous lobsters. The prevalence of ovigerous female lobsters decreased in spring and increased in fall. However, the timing of the spring and fall events, and the magnitude of the summer decrease, differed between stocks and between areas within each stock. In general, warmer areas were associated with an earlier spring decrease, a later fall increase, and a greater depletion of ovigerous females during summer. Regional differences were associated with phenological variation in egg development. Our results provide the first shelf-wide, high-resolution overview of female lobster reproductive phenology on the U.S. continental shelf and offer a foundation for future research into links between lobster reproduction and long-term shifts in harvesting, environmental conditions, and conservation policies.</div></div>","PeriodicalId":50443,"journal":{"name":"Fisheries Research","volume":"287 ","pages":"Article 107414"},"PeriodicalIF":2.2,"publicationDate":"2025-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144170176","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Fisheries ResearchPub Date : 2025-05-28DOI: 10.1016/j.fishres.2025.107418
Micah J. Quindazzi , William D.P. Duguid , Tanya Brown , Francis Juanes
{"title":"Tracking the marine migrations of coho salmon through otolith microchemistry","authors":"Micah J. Quindazzi , William D.P. Duguid , Tanya Brown , Francis Juanes","doi":"10.1016/j.fishres.2025.107418","DOIUrl":"10.1016/j.fishres.2025.107418","url":null,"abstract":"<div><div>Coho salmon (<em>Oncorhynchus kisutch</em>) are an important species to Southern British Columbia both culturally, ecologically, and economically; unfortunately, since the 1990’s significant declines in abundance and survival have occurred in this region for several populations. While marine survival rates have been declining, where these fish migrate to in the ocean within these populations has also been changing. These shifts can vary considerable from year to year, depending on the population. While tracking marine migrations with traditional tagging approach is no longer feasible given the few returns, otolith microchemistry provides an alternative approach, by comparing otoliths of adult coho that returned to the freshwater to spawn to coho caught in different marine regions: in freshwater, adults (n = 147) were collected from various hatcheries in the fall of 2017 and 2018, and in marine waters, individuals (n = 202) were collected from the Strait of Georgia (SoG) and the West Coast of Vancouver Island (WCVI) in May through July of 2017 and 2018. Otolith samples were analyzed for both trace/minor elements and stable isotopes (δ<sup>13</sup>C, δ<sup>18</sup>O). Hatchery samples were classified as either SoG residents, WCVI migrants, or unknowns using random forest classification models. Otolith chemistry of ocean caught samples from the SoG and WCVI differed from one another (F=4.754, df= 1, p < 0.001), with <sup>138</sup>Ba and δ<sup>18</sup>O being the main drivers of these differences. Random forest models were accurate (∼95 %) with low out-of-bag error rates (<10 %) across both 2017 and 2018. Freshwater caught adults were consistently assigned (≥80 % of the random forest models across set seeds) to the SoG or WCVI 83.7 % of the time. 70.6 % of 2017 samples and 38.9 % of 2018 samples were predicted to be SoG residents. Using random forest classification models, and 41.2 % of 2017 samples and 42.5 % of 2018 samples were predicted to be Strait of Georgia residents. This study is the first to demonstrate the utility of both otolith trace/minor elements and stable isotopes to track the marine migrations of Pacific salmon. The use of the otolith as an intrinsic tag provides fisheries managers with an alternative, non-fisheries dependent approach to assess the marine distributions of these fish.</div></div>","PeriodicalId":50443,"journal":{"name":"Fisheries Research","volume":"287 ","pages":"Article 107418"},"PeriodicalIF":2.2,"publicationDate":"2025-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144148101","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Fisheries ResearchPub Date : 2025-05-24DOI: 10.1016/j.fishres.2025.107416
Sean Pascoe , Natalie A. Dowling , Catherine M. Dichmont , Roy A. Deng , Ingrid van Putten , André E. Punt
{"title":"How can we increase collaboration in fisheries stock assessment?","authors":"Sean Pascoe , Natalie A. Dowling , Catherine M. Dichmont , Roy A. Deng , Ingrid van Putten , André E. Punt","doi":"10.1016/j.fishres.2025.107416","DOIUrl":"10.1016/j.fishres.2025.107416","url":null,"abstract":"<div><div>Fisheries stock assessment in some form underpins management of many fish stocks, particularly the most valuable. Quantitative stock assessments are highly technical, with a range of approaches available. Which method of stock assessment is used may influence the outcome of a stock assessment, and potentially the sustainability of the resource and harvesting sector. As with other applied research, the benefits of sharing ideas and methods to improve stock assessments is high. Collaboration in stock assessments has a range of benefits, including knowledge transfer and the associated benefits of obtaining different perspectives, such as finding solutions to modelling challenges more easily. This, in turn, can lead to time saving and avoid duplication of effort. In Australia, stock assessments are undertaken by teams of scientists geographically dispersed across the country, generally focused on stocks within their own jurisdiction. We surveyed Australian stock assessment scientists and found that most valued collaboration and engaged in collaboration in a high proportion of stock assessments, but this was mostly limited to within their organisation. We examined barriers to greater collaboration and found that these largely related to limited availability of face-to-face meetings and conferences, the lack of a readily accessible network of stock assessment scientists, and the limited time to engage in these activities. Development of a national community of practice was seen as the most preferable way to redress these issues. These issues are likely being experienced elsewhere, so the solutions found in the study may be more broadly applicable.</div></div>","PeriodicalId":50443,"journal":{"name":"Fisheries Research","volume":"287 ","pages":"Article 107416"},"PeriodicalIF":2.2,"publicationDate":"2025-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144124286","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Fisheries ResearchPub Date : 2025-05-24DOI: 10.1016/j.fishres.2025.107404
Maissa Louhichi , Marc Girondot , Imed Jribi , Alexandre Girard
{"title":"Innovative low-tech solutions for marine conservation: Phosphorescent plates reduce sea turtle bycatch and boost fishery yields","authors":"Maissa Louhichi , Marc Girondot , Imed Jribi , Alexandre Girard","doi":"10.1016/j.fishres.2025.107404","DOIUrl":"10.1016/j.fishres.2025.107404","url":null,"abstract":"<div><div>Gillnet fisheries, widely used in the Mediterranean, pose a significant threat to sea turtle populations due to high bycatch rates. This study evaluates the effectiveness of phosphorescent plates as a cost-effective, low-tech solution to mitigate sea turtle bycatch in the Gulf of Gabès, Tunisia. A paired experimental approach was conducted from 2018 to 2022 under real fishing conditions, comparing gillnets equipped with phosphorescent plates to non-illuminated control nets. Results revealed a 65 % reduction (95 %CI [51.22 % - 78.78 %]) in sea turtle bycatch in illuminated nets, with no adverse effect on target species catch rates; in fact, target fish captures increased by 25.8 % (95 %CI [13.16 % - 38.44 %]). Phosphorescent plates offer practical advantages, including long-lasting luminescence, durability, and minimal maintenance, making them an accessible solution for small-scale fisheries. Compared to LED lights, phosphorescent plates are more affordable, environmentally friendly, and easier to integrate into existing fishing practices. However, the potential environmental impact of PVC materials used in the plates warrants further investigation. These findings suggest that phosphorescent plates can enhance marine conservation efforts and fishery productivity, presenting a promising alternative for sustainable fisheries management in the Mediterranean and beyond.</div></div>","PeriodicalId":50443,"journal":{"name":"Fisheries Research","volume":"287 ","pages":"Article 107404"},"PeriodicalIF":2.2,"publicationDate":"2025-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144124285","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Fisheries ResearchPub Date : 2025-05-23DOI: 10.1016/j.fishres.2025.107402
Yunbo Xie , Nicholas A.W. Brown , Diana L. McHugh , Andrew R. Campbell , Pieter Van Will
{"title":"Using accurate insonification volumes to estimate fish abundance from acoustic survey data","authors":"Yunbo Xie , Nicholas A.W. Brown , Diana L. McHugh , Andrew R. Campbell , Pieter Van Will","doi":"10.1016/j.fishres.2025.107402","DOIUrl":"10.1016/j.fishres.2025.107402","url":null,"abstract":"<div><div>Acoustic transect-surveys paired with biological sampling of detected fish targets are an effective method for surveying fish in large freshwater and marine basins. While echo data can be deconvoluted for detected fish targets and biomass through well-established biophysical models by echo-counting, trace-counting and echo-integration methods, commonly adopted geometric models for insonification volumes of transecting sound-beams are either inaccurate or erroneous, which can significantly bias estimated fish densities and abundances for surveyed basins. In this paper, we present accurate models for insonification volumes of acoustic beams to correct these errors. The practical value of the models is demonstrated with results from the acoustic survey data acquired in two major nursery lakes for sockeye salmon (<em>Oncorhynchus nerka</em>) on Vancouver Island in British Columbia, Canada. By using the correct ping-to-ping insonification volumes and taking considerations of unsampled volumes in the upper water column, estimates using accurate insonification volumes were within a 5 % difference between the echo-counting and trace-counting biophysical models. The presented results and methodologies can be readily replicated and are broadly applicable to acoustic surveys of fish abundance in freshwater and marine environments.</div></div>","PeriodicalId":50443,"journal":{"name":"Fisheries Research","volume":"287 ","pages":"Article 107402"},"PeriodicalIF":2.2,"publicationDate":"2025-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144114718","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Fisheries ResearchPub Date : 2025-05-22DOI: 10.1016/j.fishres.2025.107415
Ignacio A. Catalán , Amaya Álvarez-Ellacuría , Manuel Hidalgo , Hilmar Hinz , Ismael Rodríguez , Miquel Palmer
{"title":"High-resolution spatial and temporal analysis of hake length distribution in relation to environmental drivers","authors":"Ignacio A. Catalán , Amaya Álvarez-Ellacuría , Manuel Hidalgo , Hilmar Hinz , Ismael Rodríguez , Miquel Palmer","doi":"10.1016/j.fishres.2025.107415","DOIUrl":"10.1016/j.fishres.2025.107415","url":null,"abstract":"<div><div>Mediterranean fisheries face critical challenges, with European hake (<em>Merluccius merluccius</em>) exemplifying both high ecological and commercial value and severe overexploitation. Sustainable management is further complicated by the species’ complex spatial population structure, necessitating high-resolution data such as on length distributions. In this study, we applied artificial intelligence to produce continuous spatial and temporal data on hake length distributions at the boat-day level in Mallorca Island, representative of one of the Mediterranean geographical statistical subareas within FAO major fishing area 37. Analyzing over 18,000 images of landed hake boxes from 2021 to 2023, our method captured approximately 77 % of the landed biomass, ensuring representative coverage of diverse fishing grounds. By integrating Self-Organizing Maps, Random Forest, and Generalized Linear Mixed Models, we identified depth and geographical areas as a key drivers of hake size: smaller individuals predominated in shallow NE and SW zones, corresponding with known juvenile habitats. Seasonal patterns further revealed an increased prevalence of small-length classes during spring and autumn-winter. Although variations in catch length were largely boat-specific-reflecting métier-based strategies-this approach enabled the detection of subpopulation dynamics. This approach offers a cost-effective, fisheries-dependent tool that complements existing data sources. The high-resolution, spatially explicit insights gained here provide a valuable foundation for adaptive, regionally tailored management strategies aimed at ensuring sustainable Mediterranean fisheries.</div></div>","PeriodicalId":50443,"journal":{"name":"Fisheries Research","volume":"287 ","pages":"Article 107415"},"PeriodicalIF":2.2,"publicationDate":"2025-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144115117","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Fisheries ResearchPub Date : 2025-05-19DOI: 10.1016/j.fishres.2025.107399
Noland O. Michels , Thomas R. Hrabik , Quinnlan C. Smith , Greg G. Sass , Allen F. Mensinger
{"title":"The effects of light intensity and water clarity on growth rates of age-0 walleye (Sander vitreus)","authors":"Noland O. Michels , Thomas R. Hrabik , Quinnlan C. Smith , Greg G. Sass , Allen F. Mensinger","doi":"10.1016/j.fishres.2025.107399","DOIUrl":"10.1016/j.fishres.2025.107399","url":null,"abstract":"<div><div>Growth rates in fish are a function of temperature and may also be dependent on successful foraging periods. Successful foraging of visually mediated piscivores is often contingent on available light. In north-temperate lakes, tannin concentrations can absorb downwelling light leading to lower light intensities which may influence fish foraging success and growth. We tested tannin and light intensity effects on wild age-0 walleye <em>Sander vitreus</em> growth, which may have implications for survivorship and recruitment. Age-0 walleye (127–182 mm TL) were held under three light intensities (3.16 × 10<sup>14</sup>, 3.16 × 10<sup>15</sup>, and 2.88 × 10<sup>17</sup> photons m<sup>−2</sup> s<sup>−1</sup>) and tannin concentrations (0 mg/L, 10 mg/L, and 20 mg/L). Walleye were grown at 18 °C for 16 days and TL (mm) and weight (g) were measured at days 0, 8, and 16. The number of fathead minnow (<em>Pimephales promelas</em>; 31–42 mm total length) consumed was recorded each day. Age-0 walleye growth was positive, ranging from 0.0092 g g<sup>−1</sup> day<sup>−1</sup> at 9.44 × 10<sup>15</sup> photons m<sup>−2</sup> s<sup>−1</sup> (∼750 lx surface intensity) in clear water to 0.0223 g g<sup>−1</sup> day<sup>−1</sup> at 1.58 × 10<sup>15</sup> photons m<sup>−2</sup> s<sup>−1</sup> (∼10 lx surface intensity) in heavily stained water. Growth was greatest in low light conditions and heavily stained waters. Our results suggest that heavily stained lakes and rivers with good optical refuge where light intensity is reduced at depth may be best for juvenile walleye growth.</div></div>","PeriodicalId":50443,"journal":{"name":"Fisheries Research","volume":"287 ","pages":"Article 107399"},"PeriodicalIF":2.2,"publicationDate":"2025-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144083721","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Fisheries ResearchPub Date : 2025-05-16DOI: 10.1016/j.fishres.2025.107403
Nicholas C. Wegner , Lyall Bellquist , Roberto Silva , John R. Hyde
{"title":"Juvenile and small adult cowcod (Sebastes levis) show high post-release survival following angling-induced barotrauma","authors":"Nicholas C. Wegner , Lyall Bellquist , Roberto Silva , John R. Hyde","doi":"10.1016/j.fishres.2025.107403","DOIUrl":"10.1016/j.fishres.2025.107403","url":null,"abstract":"<div><div>The cowcod, <em>Sebastes levis</em>, is a large slow-growing rockfish species found along the West Coast of the United States and Baja California, Mexico that has been historically heavily exploited off of southern California. As the cowcod population recovers from past overfishing, previously closed fishing areas and depths are reopening, leading to increased fisher interactions with the species, particularly juveniles and small adults, which are typically found at shallower depths closer to shore. In this study, we quantify post-release survival rates of juvenile and small adult cowcod (< 50 cm) following angling-induced barotrauma in comparison to previous work focused on larger adult cowcod. All cowcod were captured using recreational hook-and-line gear and descended back to depth using commercially available fish descending devices. Kaplan-Meier survivorship modeling showed an overall survival rate of 92.9 % (95 % CI: 80.3–100 %) for the 14 cowcod examined (22.9–49.5 cm fork length). This survival rate was nearly twice that determined previously for larger cowcod. The higher survival rate of smaller individuals may reflect their thinner tissues, allowing for expanding gas from the swim bladder to escape the body, thereby preventing some of the severe internal organ damage typically associated with barotrauma in larger cowcod. Combination of our results with previous research thus suggests that small cowcod caught by recreational anglers can be released with high survival rates, while larger cowcod are less likely to survive capture and barotrauma.</div></div>","PeriodicalId":50443,"journal":{"name":"Fisheries Research","volume":"287 ","pages":"Article 107403"},"PeriodicalIF":2.2,"publicationDate":"2025-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144068106","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Fisheries ResearchPub Date : 2025-05-16DOI: 10.1016/j.fishres.2025.107400
Holly Gunton , Ashley M. Fowler , David J. Booth , John Stewart
{"title":"Patterns and drivers of movement in the estuary-associated sparid Acanthopagrus australis from a large-scale tagging study","authors":"Holly Gunton , Ashley M. Fowler , David J. Booth , John Stewart","doi":"10.1016/j.fishres.2025.107400","DOIUrl":"10.1016/j.fishres.2025.107400","url":null,"abstract":"<div><div>Knowledge of fish movement is essential for implementing appropriate spatial scales of stock assessment and management. This study examines the movement patterns of an important fisheries species <em>Acanthopagrus australis</em>, yellowfin bream, along Australia’s east coast using data from a cooperative tag-recapture program. More than 24, 000 individuals were tagged and released across ∼ 800 km of coastline, with recreational anglers recapturing 2, 036 (8.2 %) individuals during a 19-year period. While a broad range of movements was observed (0–832 km), only 8.6 % of fish moved further than 100 km and a substantial proportion (37 %) of individuals were recaptured at their release location. Generalized additive models indicated that fish were more likely to move if they spent greater time at liberty, were of larger body length at release, and were released during Autumn. Movement distance was greater if fish moved in a northerly direction, spent greater time at liberty and were released at more southerly latitudes. The results indicate that movement of yellowfin bream is restricted over a relatively small spatial scale (< 100 km), with occasional larger movements consistent with multiple behavioural types. The findings suggest that monitoring, assessment and management at a finer spatial scale than the current state-wide approach may be warranted to ensure sustainable fisheries management.</div></div>","PeriodicalId":50443,"journal":{"name":"Fisheries Research","volume":"287 ","pages":"Article 107400"},"PeriodicalIF":2.2,"publicationDate":"2025-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144070783","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Fisheries ResearchPub Date : 2025-05-15DOI: 10.1016/j.fishres.2025.107406
Chengbin Zhang , Ying Xiong , Dade Song , Hushun Zhang , Shuyan Wang , Zhongjie Kang , Long Liang
{"title":"Analysis of the fishing intensity and management status of Anguilla japonica fry in the north coast of the Yangtze River Estuary- based on BeiDou VMS data and licenses data","authors":"Chengbin Zhang , Ying Xiong , Dade Song , Hushun Zhang , Shuyan Wang , Zhongjie Kang , Long Liang","doi":"10.1016/j.fishres.2025.107406","DOIUrl":"10.1016/j.fishres.2025.107406","url":null,"abstract":"<div><div>The Japanese eel (<em>Anguilla japonica</em>) is one of the Red List of Threatened Species as an “endangered” species in the International Union for Conservation of Nature (IUCN). This study focused on analysing the fishing characteristics of fishing vessels targeting Japanese eel fry (glass eels) within Chinese waters and examining current management practices for this species. We analyzed the fishing behavior of 497 vessels along the north coast of the Yangtze River Estuary using data from the BeiDou Vessel Monitoring System (VMS). Key study insights included the following. (1) The correspondence between vessels' actual fishing range and licensed-designated fishing zones was approximately 48.6 %. (2) The observed fleets mainly fell into two operational categories: Single-vessel (a single vessel fishing independently, SV), representing 15.1 % of the fleets, and Primary-secondary-vessel (where a primary-vessel carries one to three secondary-vessels to the fishing area, anchors, and releases the secondary-vessels to fish independently, PSV), representing 84.9 %. (3) For SVs, fishing areas are categorised into one, two, and more than three areas. (4) Fishing areas varied by vessel size: vessels under 12 m primarily operated in offshore waters at 0–20 m depths, and those over 24 m operated in deeper offshore waters at depths of 20–40 m. In comparison, vessels between 12 and 24 m were located in intermediate areas. (5) Fishing intensity varied significantly across regions, with the highest concentration observed in coastal waters at 0–20 m depth off Rudong waters and Dongtai waters, where fishing density reached 13–18 vessels/100 km<sup>2</sup>. (6) Since the implementation of the Yangtze River Estuary Fishing Ban Zone in 2021, the core fishing grounds of eel fry fishing has shifted from the Haimen at the Yangtze River Estuary to the Rudong and the Dongtai sea waters. Based on the aforementioned research outcomes, the following recommendations are proposed: 1) For PSVs, fishery management authorities should mandate the standardised installation of BeiDou VMS on secondary-vessels. 2) It is advisable to enact regulations stipulating the permissible quantity of fishing nets carried by vessels based on their specifications.</div></div>","PeriodicalId":50443,"journal":{"name":"Fisheries Research","volume":"287 ","pages":"Article 107406"},"PeriodicalIF":2.2,"publicationDate":"2025-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143947741","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}