Coastal waters are important habitats for the endangered European eel. In a large-scale experiment marked glass eels were released in two geographically distinct coastal areas in the southern Baltic Sea. Generalized linear mixed models were used to test for effects of restocking on yellow eel density as well as eel condition and growth following a before-after-control-impact analysis design. Alongside of increased natural immigration, restocking distinctly increased the yellow eel density by around 1.5–3 times in both restocked areas compared with densities recorded before the release. Increased densities by restocking did not generally lead to slower growth, altered body condition, or a change in the sex ratio of naturally immigrated eels. Restocked eels had comparable condition and grew somewhat faster than naturally immigrated eels in both restocked areas within the first three years after restocking. These results suggest, that the habitat capacity for eels in the restocked areas was not reached by the current natural settlement in combination with the released eels. Therefore, eel restocking in coastal waters seems to be a useful management option to locally increase the escapement rate of mature silver eels.
{"title":"Large-scale experiment demonstrates potential benefits of restocking glass eels in coastal waters of the southern Baltic Sea","authors":"Janek Simon , Tyrell DeWeber , Jens Frankowski , Malte Dorow","doi":"10.1016/j.fishres.2026.107651","DOIUrl":"10.1016/j.fishres.2026.107651","url":null,"abstract":"<div><div>Coastal waters are important habitats for the endangered European eel. In a large-scale experiment marked glass eels were released in two geographically distinct coastal areas in the southern Baltic Sea. Generalized linear mixed models were used to test for effects of restocking on yellow eel density as well as eel condition and growth following a before-after-control-impact analysis design. Alongside of increased natural immigration, restocking distinctly increased the yellow eel density by around 1.5–3 times in both restocked areas compared with densities recorded before the release. Increased densities by restocking did not generally lead to slower growth, altered body condition, or a change in the sex ratio of naturally immigrated eels. Restocked eels had comparable condition and grew somewhat faster than naturally immigrated eels in both restocked areas within the first three years after restocking. These results suggest, that the habitat capacity for eels in the restocked areas was not reached by the current natural settlement in combination with the released eels. Therefore, eel restocking in coastal waters seems to be a useful management option to locally increase the escapement rate of mature silver eels.</div></div>","PeriodicalId":50443,"journal":{"name":"Fisheries Research","volume":"293 ","pages":"Article 107651"},"PeriodicalIF":2.3,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145925291","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}
Pub Date : 2026-01-01DOI: 10.1016/j.fishres.2026.107650
Joel Anderson, Isabelle Cummings, Zachary Olsen, Mark Fisher
The Atlantic Croaker Micropogonias undulatus is a key estuarine-dependent species in Texas and the greater Gulf of Mexico, particularly as the target for a commercial bait fishery but also as one of the most common bycatch species encountered in commercial shrimp trawls. Declining effort in the inshore (estuarine) shrimp trawl fishery in Texas since the 1990s has resulted in increasing abundance of Atlantic Croaker, although a concurrent change in mean body size has not been explored. Here, the observed abundance of Atlantic Croaker in fishery-independent trawls was related to observed mean total body length in trawls, fishery-independent gill nets, and observed recreational angler harvest from boat ramp intercepts centered on the eight major bay areas of Texas. Annual abundance estimates correlated negatively and significantly with mean size in trawls in 7/8 bays, in gill nets in 4/8 bays, and in angler harvest data in 1/8 bays. Annual growth rate parameters (k) for young-of-the-year specimens were developed using size-filtered monthly bag seine and trawl length-frequency data, and the magnitude of k was tightly and negatively correlated with annual abundance coast-wide. Body size of Atlantic Croaker in Texas is driven by annual abundance, and growth of Atlantic Croaker is relatively slow in years when abundance is relatively high. Observed increases in abundance driven by reduced bycatch mortality are driving long-term declines in body size in Texas, which may ultimately drive changes to mean body size in the recreational harvest and commercial bait fisheries.
{"title":"Body size of Atlantic Croaker Micropogonias undulatus in Texas is density dependent","authors":"Joel Anderson, Isabelle Cummings, Zachary Olsen, Mark Fisher","doi":"10.1016/j.fishres.2026.107650","DOIUrl":"10.1016/j.fishres.2026.107650","url":null,"abstract":"<div><div>The Atlantic Croaker <em>Micropogonias undulatus</em> is a key estuarine-dependent species in Texas and the greater Gulf of Mexico, particularly as the target for a commercial bait fishery but also as one of the most common bycatch species encountered in commercial shrimp trawls. Declining effort in the inshore (estuarine) shrimp trawl fishery in Texas since the 1990s has resulted in increasing abundance of Atlantic Croaker, although a concurrent change in mean body size has not been explored. Here, the observed abundance of Atlantic Croaker in fishery-independent trawls was related to observed mean total body length in trawls, fishery-independent gill nets, and observed recreational angler harvest from boat ramp intercepts centered on the eight major bay areas of Texas. Annual abundance estimates correlated negatively and significantly with mean size in trawls in 7/8 bays, in gill nets in 4/8 bays, and in angler harvest data in 1/8 bays. Annual growth rate parameters (<em>k</em>) for young-of-the-year specimens were developed using size-filtered monthly bag seine and trawl length-frequency data, and the magnitude of <em>k</em> was tightly and negatively correlated with annual abundance coast-wide. Body size of Atlantic Croaker in Texas is driven by annual abundance, and growth of Atlantic Croaker is relatively slow in years when abundance is relatively high. Observed increases in abundance driven by reduced bycatch mortality are driving long-term declines in body size in Texas, which may ultimately drive changes to mean body size in the recreational harvest and commercial bait fisheries.</div></div>","PeriodicalId":50443,"journal":{"name":"Fisheries Research","volume":"293 ","pages":"Article 107650"},"PeriodicalIF":2.3,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145925288","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}
Pub Date : 2026-01-01DOI: 10.1016/j.fishres.2025.107643
Richard H. Parrish , D.B. Pleschner
Pacific sardine is a dynamic population that undergoes natural boom-and-bust cycles. Despite sardines’ ecological and economic importance, the variability that governs population changes remains poorly understood. Understanding the influence of oceanography on the life history, migration, and population dynamics of sardines is important for fishery management. Over the history of the California Current sardine fishery, numerous studies have attempted to explain why the US and Mexican portions of the sardine biomass off the West Coast should be divided into Northern (Cold - NSP) and Southern (Temperate - SSP) subpopulations. Since 2015, a habitat model including a Sea Surface Temperature (SST) threshold has been used to delineate subpopulations. The assessment and management of the NSP is conducted by the US (using an SST threshold of 16.7° C), while that of the SSP has been conducted by Mexico (using a threshold of 17 °C). Meantime, new population genetics and stock structure studies have found that the reproductive ecology of Pacific sardine reflects a single, panmictic population spread over a wide geographic range and influenced by environmental forcing, suggesting that assumptions regarding the two-subpopulation hypothesis be reconsidered, along with the influence of oceanography on sardine population dynamics. The implications of a single sardine population are significant, as this could result in a review of current US fishery management policies and reference points used to set the annual fishing quotas. In this paper we discuss the importance of the California Current’s influence on the population dynamics of sardine, current fishery management, and management implications.
{"title":"Conflicts in science and management: The case for Pacific sardine","authors":"Richard H. Parrish , D.B. Pleschner","doi":"10.1016/j.fishres.2025.107643","DOIUrl":"10.1016/j.fishres.2025.107643","url":null,"abstract":"<div><div>Pacific sardine is a dynamic population that undergoes natural boom-and-bust cycles. Despite sardines’ ecological and economic importance, the variability that governs population changes remains poorly understood. Understanding the influence of oceanography on the life history, migration, and population dynamics of sardines is important for fishery management. Over the history of the California Current sardine fishery, numerous studies have attempted to explain why the US and Mexican portions of the sardine biomass off the West Coast should be divided into Northern (Cold - NSP) and Southern (Temperate - SSP) subpopulations. Since 2015, a habitat model including a Sea Surface Temperature (SST) threshold has been used to delineate subpopulations. The assessment and management of the NSP is conducted by the US (using an SST threshold of 16.7° C), while that of the SSP has been conducted by Mexico (using a threshold of 17 °C). Meantime, new population genetics and stock structure studies have found that the reproductive ecology of Pacific sardine reflects a single, panmictic population spread over a wide geographic range and influenced by environmental forcing, suggesting that assumptions regarding the two-subpopulation hypothesis be reconsidered, along with the influence of oceanography on sardine population dynamics. The implications of a single sardine population are significant, as this could result in a review of current US fishery management policies and reference points used to set the annual fishing quotas. In this paper we discuss the importance of the California Current’s influence on the population dynamics of sardine, current fishery management, and management implications.</div></div>","PeriodicalId":50443,"journal":{"name":"Fisheries Research","volume":"293 ","pages":"Article 107643"},"PeriodicalIF":2.3,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145884473","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}
Pub Date : 2026-01-01DOI: 10.1016/j.fishres.2026.107648
Topi K. Lehtonen , Lari Veneranta , Oliver Bitz , Daniel Fischer , Miika Tapio , Tuomas Leinonen
Fisheries management units—i.e. ’stocks’—frequently match poorly with biological variation. This mismatch poses a management challenge particularly when within-species units differ in their resilience to harvesting. It is therefore essential to both identify the distinct biological units and adjust fishing pressure accordingly. In the northern Baltic Sea, the European whitefish (Coregonus lavaretus) has two ecotypes, anadromous and sea-spawning, harvested primarily with gillnets. The former is endangered due to river connectivity issues and fishing pressure, while the latter is faring better. However, the key elements of effective management, accurate stock component identification and stock-component-specific fishing pressure adjustment, have not been assessed in this mixed-stock fishery. To address this knowledge gap, we compared ecotype identification methods and examined how fishing depth, season, and gillnet mesh size influence the whitefish catch composition. First, we assessed how well the ecotypes could be identified using phenotypic traits (gill rakers and growth) and genetic data (SNP genotyping). While both approaches were useful, many individuals exhibited intermediate characteristics and were not reliably identified, with phenotypic and genetic identification approaches agreeing only moderately. The prevalence of individuals with intermediate traits may reflect past stocking practices, habitat degradation, or inherently inconsistent homing behaviour. Nevertheless, we caught a higher share of sea-spawner-like individuals from deeper waters, earlier in the season, and with gillnets of smaller mesh size. The fact that it was possible to markedly affect the catch composition suggests that spatial and temporal fishing regulations have potential in the management of whitefish mixed-stock fisheries.
{"title":"Challenges in mixed-stock fishery management: The case of the European whitefish in Kvarken, northern Baltic Sea","authors":"Topi K. Lehtonen , Lari Veneranta , Oliver Bitz , Daniel Fischer , Miika Tapio , Tuomas Leinonen","doi":"10.1016/j.fishres.2026.107648","DOIUrl":"10.1016/j.fishres.2026.107648","url":null,"abstract":"<div><div>Fisheries management units—i.e. ’stocks’—frequently match poorly with biological variation. This mismatch poses a management challenge particularly when within-species units differ in their resilience to harvesting. It is therefore essential to both identify the distinct biological units and adjust fishing pressure accordingly. In the northern Baltic Sea, the European whitefish (<em>Coregonus lavaretus</em>) has two ecotypes, anadromous and sea-spawning, harvested primarily with gillnets. The former is endangered due to river connectivity issues and fishing pressure, while the latter is faring better. However, the key elements of effective management, accurate stock component identification and stock-component-specific fishing pressure adjustment, have not been assessed in this mixed-stock fishery. To address this knowledge gap, we compared ecotype identification methods and examined how fishing depth, season, and gillnet mesh size influence the whitefish catch composition. First, we assessed how well the ecotypes could be identified using phenotypic traits (gill rakers and growth) and genetic data (SNP genotyping). While both approaches were useful, many individuals exhibited intermediate characteristics and were not reliably identified, with phenotypic and genetic identification approaches agreeing only moderately. The prevalence of individuals with intermediate traits may reflect past stocking practices, habitat degradation, or inherently inconsistent homing behaviour. Nevertheless, we caught a higher share of sea-spawner-like individuals from deeper waters, earlier in the season, and with gillnets of smaller mesh size. The fact that it was possible to markedly affect the catch composition suggests that spatial and temporal fishing regulations have potential in the management of whitefish mixed-stock fisheries.</div></div>","PeriodicalId":50443,"journal":{"name":"Fisheries Research","volume":"293 ","pages":"Article 107648"},"PeriodicalIF":2.3,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145925289","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}
Monitoring the survival rates of stocked fish is important for the success of stocking programs. Stocked fish reared in artificial environments may exhibit reduced performance until they adapt to the natural environment, potentially leading to a high loss rate immediately after stocking. In this study, we conducted high-frequency tracking of farmed Japanese eels Anguilla japonica stocked into the Fukada River (small size, no previous stocking) and the Amikake River (larger size, previous stocking) in Japan, starting from the first day after stocking using a mobile Radio Frequency Identification system. Apparent survival rates of stocked eels including mortality and emigration was estimated using the Cormack–Jolly–Seber (CJS) model with state-space formulations. The CJS model showed that apparent survival rates of stocked eels were lowest during the initial detection survey after stocking (i.e., on the first day in the Fukada River and during the first four days in the Amikake River), and then the rates gradually increased over time. These results suggest that stocked eels experience significant depletion within the initial days following stocking. Emigration and predation were inferred as potential causes of the high loss rate in the initial phase following stocking. Furthermore, the CJS model also showed that smaller stocked eels with high condition factors exhibited higher apparent survival rates. This study highlighted that identifying effective stocking methods to improve post-release survival is essential for enhancing the local catch and population of Japanese eels.
{"title":"Rapid loss rates of farmed Japanese eels stocked into two different rivers","authors":"Kota Takeuchi , Hikaru Itakura , Tatsuhiko Maeda , Seishi Hagihara , Shingo Kimura , Kazuhiko Anraku , Tomonari Kotani , Ryoshiro Wakiya","doi":"10.1016/j.fishres.2025.107647","DOIUrl":"10.1016/j.fishres.2025.107647","url":null,"abstract":"<div><div>Monitoring the survival rates of stocked fish is important for the success of stocking programs. Stocked fish reared in artificial environments may exhibit reduced performance until they adapt to the natural environment, potentially leading to a high loss rate immediately after stocking. In this study, we conducted high-frequency tracking of farmed Japanese eels <em>Anguilla japonica</em> stocked into the Fukada River (small size, no previous stocking) and the Amikake River (larger size, previous stocking) in Japan, starting from the first day after stocking using a mobile Radio Frequency Identification system. Apparent survival rates of stocked eels including mortality and emigration was estimated using the Cormack–Jolly–Seber (CJS) model with state-space formulations. The CJS model showed that apparent survival rates of stocked eels were lowest during the initial detection survey after stocking (i.e., on the first day in the Fukada River and during the first four days in the Amikake River), and then the rates gradually increased over time. These results suggest that stocked eels experience significant depletion within the initial days following stocking. Emigration and predation were inferred as potential causes of the high loss rate in the initial phase following stocking. Furthermore, the CJS model also showed that smaller stocked eels with high condition factors exhibited higher apparent survival rates. This study highlighted that identifying effective stocking methods to improve post-release survival is essential for enhancing the local catch and population of Japanese eels.</div></div>","PeriodicalId":50443,"journal":{"name":"Fisheries Research","volume":"293 ","pages":"Article 107647"},"PeriodicalIF":2.3,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145925357","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}
Pub Date : 2026-01-01DOI: 10.1016/j.fishres.2025.107645
Kelly Dunning , TiAnna Olivas , Caleb Camus , Hannah Henry , Sarah Gumbleton , Nicole Beckham , Janna R. Willoughby
Human-wildlife conflicts in commercial fisheries can affect both marine wildlife populations and fishery livelihoods. This study examines interactions between commercial shrimpers and two federally protected species in the U.S. state of Alabama: bottlenose dolphins (Tursiops truncatus) and sea turtles (Chelonia mydas, Caretta caretta, Lepidochelys kempii). Using semi-structured interviews with 14 shrimpers, we identified two main conflict types with dolphins: depredation, where dolphins remove target shrimp or fish from actively hauled nets, and scavenging, where dolphins consume discarded bycatch. Respondents reported that depredation causes direct economic losses and gear damage, while scavenging can slow operations and condition dolphins to associate boats with food, potentially increasing future depredation. These behaviors were perceived as increasing in frequency and intensity, suggesting shifts in dolphin foraging behavior due to human activity. In contrast, human-wildlife conflict with sea turtles was rare, reflecting widespread adoption of turtle excluder devices (TEDs). While TEDs are largely effective at reducing turtle bycatch, respondents noted that debris accumulation and incidental loss of target catch can create additional scavenging opportunities for dolphins, illustrating the need to consider multi-species management. Opinions among shrimpers about TEDs’ efficacy and economic impacts were mixed, highlighting ongoing challenges in balancing conservation and industry needs. This research emphasizes the value of participatory, qualitative approaches: interviews were co-designed with state and federal managers to capture shrimpers’ local ecological knowledge, providing actionable insights for species recovery and post-Deepwater Horizon ecosystem restoration. Findings underscore the importance of adaptive, ecosystem-based management, technological innovation in fishing gear, and stakeholder engagement to reduce conflicts, maintain fishery productivity, and support marine wildlife conservation. Lessons from Alabama’s shrimp fishery offer broader implications for other coastal regions where multi-species interactions influence both management outcomes and human livelihoods.
{"title":"An analysis of the marine wildlife interactions with the commercial shrimping industry on the Alabama Gulf Coast","authors":"Kelly Dunning , TiAnna Olivas , Caleb Camus , Hannah Henry , Sarah Gumbleton , Nicole Beckham , Janna R. Willoughby","doi":"10.1016/j.fishres.2025.107645","DOIUrl":"10.1016/j.fishres.2025.107645","url":null,"abstract":"<div><div>Human-wildlife conflicts in commercial fisheries can affect both marine wildlife populations and fishery livelihoods. This study examines interactions between commercial shrimpers and two federally protected species in the U.S. state of Alabama: bottlenose dolphins (<em>Tursiops truncatus</em>) and sea turtles (<em>Chelonia mydas</em>, <em>Caretta caretta</em>, <em>Lepidochelys kempii</em>). Using semi-structured interviews with 14 shrimpers, we identified two main conflict types with dolphins: depredation, where dolphins remove target shrimp or fish from actively hauled nets, and scavenging, where dolphins consume discarded bycatch. Respondents reported that depredation causes direct economic losses and gear damage, while scavenging can slow operations and condition dolphins to associate boats with food, potentially increasing future depredation. These behaviors were perceived as increasing in frequency and intensity, suggesting shifts in dolphin foraging behavior due to human activity. In contrast, human-wildlife conflict with sea turtles was rare, reflecting widespread adoption of turtle excluder devices (TEDs). While TEDs are largely effective at reducing turtle bycatch, respondents noted that debris accumulation and incidental loss of target catch can create additional scavenging opportunities for dolphins, illustrating the need to consider multi-species management. Opinions among shrimpers about TEDs’ efficacy and economic impacts were mixed, highlighting ongoing challenges in balancing conservation and industry needs. This research emphasizes the value of participatory, qualitative approaches: interviews were co-designed with state and federal managers to capture shrimpers’ local ecological knowledge, providing actionable insights for species recovery and post-Deepwater Horizon ecosystem restoration. Findings underscore the importance of adaptive, ecosystem-based management, technological innovation in fishing gear, and stakeholder engagement to reduce conflicts, maintain fishery productivity, and support marine wildlife conservation. Lessons from Alabama’s shrimp fishery offer broader implications for other coastal regions where multi-species interactions influence both management outcomes and human livelihoods.</div></div>","PeriodicalId":50443,"journal":{"name":"Fisheries Research","volume":"293 ","pages":"Article 107645"},"PeriodicalIF":2.3,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145976620","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}
Pub Date : 2026-01-01DOI: 10.1016/j.fishres.2026.107649
Sónia Seixas , Alexandra Baeta , João C. Marques
This study explores the feeding ecology of Octopus vulgaris in the Cascais region through a combined approach of long-term prey monitoring and stable isotope analysis. Over several months, we worked with local fishermen to observe and record prey items found in octopus pots and those carried by octopuses at the time of capture. These field observations enabled the identification of key prey species, which were subsequently analysed isotopically to estimate their contribution to the octopus diet. The results show that Atrina fragilis is the main prey, making up about 70 %, followed by Polybius henslowii (18 %), with Cymbium olla and Cepola macrophthalma contributing smaller amounts. Our findings highlight the limitations of traditional stomach content analysis, which often underestimates soft-bodied or highly digested prey, and emphasise the importance of isotopic methods to provide a more comprehensive and long-term view of trophic interactions. This integrated approach enhances our understanding of O. vulgaris feeding strategies and has significant implications for ecological research and the sustainable management of fisheries in the region.
{"title":"Integrating prey monitoring and stable isotope analysis to assess the diet of Octopus vulgaris in Portuguese coastal waters","authors":"Sónia Seixas , Alexandra Baeta , João C. Marques","doi":"10.1016/j.fishres.2026.107649","DOIUrl":"10.1016/j.fishres.2026.107649","url":null,"abstract":"<div><div>This study explores the feeding ecology of <em>Octopus vulgaris</em> in the Cascais region through a combined approach of long-term prey monitoring and stable isotope analysis. Over several months, we worked with local fishermen to observe and record prey items found in octopus pots and those carried by octopuses at the time of capture. These field observations enabled the identification of key prey species, which were subsequently analysed isotopically to estimate their contribution to the octopus diet. The results show that Atrina fragilis is the main prey, making up about 70 %, followed by <em>Polybius henslowii</em> (18 %), with <em>Cymbium olla</em> and <em>Cepola macrophthalma</em> contributing smaller amounts. Our findings highlight the limitations of traditional stomach content analysis, which often underestimates soft-bodied or highly digested prey, and emphasise the importance of isotopic methods to provide a more comprehensive and long-term view of trophic interactions. This integrated approach enhances our understanding of O. vulgaris feeding strategies and has significant implications for ecological research and the sustainable management of fisheries in the region.</div></div>","PeriodicalId":50443,"journal":{"name":"Fisheries Research","volume":"293 ","pages":"Article 107649"},"PeriodicalIF":2.3,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145976623","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}
Pub Date : 2026-01-01DOI: 10.1016/j.fishres.2026.107653
J.H. Colonello, F. Cortés, C.D. Álvarez, M.C. Risoli, M.A. Pérez
In response to growing global concern, various international committees and national and regional action plans have emphasized the need for research focused on the conservation and sustainable use of the porbeagle shark. In the Southwest Atlantic, this species is incidentally caught by commercial longline and trawl fleets, with varying intensities depending on the area and type of fishery. This study is based on data collected by scientific observers onboard Argentine trawl freezer and factory vessels operating south of 51°S between 2006 and 2021. It had three main objectives: to estimate the annual bycatch of porbeagle shark; to estimate standardized catch per unit effort as a proxy for regional species density in the Southwest Atlantic Ocean; and to update the annual standardized bycatch index originally developed for the surimi fleet. Porbeagle shark occurrence frequency increased with depth, showing two distinct peaks around 500 and 1200 m. Higher frequencies were recorded east of 64ºW and south of 54ºS, with monthly peaks during the first half of the year, although interannual variation was observed. Occurrence was higher in surimi vessels, particularly when using semi-pelagic gear. The regional standardized porbeagle shark density index fluctuated over the study period without a clear trend, although notable peaks occurred in certain years. Notwithstanding its limitations, this study provides indicators that represent a useful starting point for assessing the status of porbeagle shark populations in the Southwest Atlantic and for contributing to future stock assessments. This information is particularly relevant because it originates from latitudes located farther south within the porbeagle shark’s distribution than those encompassed by other Atlantic datasets. The study area also holds ecological importance as a feeding ground, particularly for mature, pregnant females that remain in the region during summer and autumn before migrating to mid-latitudes.
{"title":"Annual bycatch and regional density of the porbeagle shark Lamna nasus in the austral Southwest Atlantic Ocean","authors":"J.H. Colonello, F. Cortés, C.D. Álvarez, M.C. Risoli, M.A. Pérez","doi":"10.1016/j.fishres.2026.107653","DOIUrl":"10.1016/j.fishres.2026.107653","url":null,"abstract":"<div><div>In response to growing global concern, various international committees and national and regional action plans have emphasized the need for research focused on the conservation and sustainable use of the porbeagle shark. In the Southwest Atlantic, this species is incidentally caught by commercial longline and trawl fleets, with varying intensities depending on the area and type of fishery. This study is based on data collected by scientific observers onboard Argentine trawl freezer and factory vessels operating south of 51°S between 2006 and 2021. It had three main objectives: to estimate the annual bycatch of porbeagle shark; to estimate standardized catch per unit effort as a proxy for regional species density in the Southwest Atlantic Ocean; and to update the annual standardized bycatch index originally developed for the surimi fleet. Porbeagle shark occurrence frequency increased with depth, showing two distinct peaks around 500 and 1200 m. Higher frequencies were recorded east of 64ºW and south of 54ºS, with monthly peaks during the first half of the year, although interannual variation was observed. Occurrence was higher in surimi vessels, particularly when using semi-pelagic gear. The regional standardized porbeagle shark density index fluctuated over the study period without a clear trend, although notable peaks occurred in certain years. Notwithstanding its limitations, this study provides indicators that represent a useful starting point for assessing the status of porbeagle shark populations in the Southwest Atlantic and for contributing to future stock assessments. This information is particularly relevant because it originates from latitudes located farther south within the porbeagle shark’s distribution than those encompassed by other Atlantic datasets. The study area also holds ecological importance as a feeding ground, particularly for mature, pregnant females that remain in the region during summer and autumn before migrating to mid-latitudes.</div></div>","PeriodicalId":50443,"journal":{"name":"Fisheries Research","volume":"293 ","pages":"Article 107653"},"PeriodicalIF":2.3,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145925290","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}
Pub Date : 2026-01-01DOI: 10.1016/j.fishres.2025.107646
Andy Manuel Escalante-Domínguez , Ximena Renán , Gabriela Galindo-Cortes , Teresa Colás-Marrufo , Thierry Brulé
Obtaining data on the population structure of Lutjanus analis is crucial, as species with low to moderate growth tend to decline faster with fishing pressure. Even though Lutjanus analis is an economically important species in the southern Gulf of Mexico, age-based life history parameters and the selection of the optimal growth model from three possible (von Bertalanffy, Gompertz, and logistic) were acquired for the first time. Collections were done by the semi-industrial and artisanal fishing fleets from January 2018 to July 2023 (n = 433; FL = 19.0 – 79.3 cm, TW = 0.13 – 9.10 kg). Marginal increment analysis confirmed annulus formation from March to June. Age ranged from 0+ to 28 years, with the most frequent ages between 4 – 5 years. The von Bertalanffy growth model was the most efficient to describe growth (L∞ = 76.08 cm, K = 0.17 yr−1, t0 = −1.57). Estimated lifespan was 16.07 years. There were no statistical differences in growth trajectories between sexes. Nevertheless, age at sexual maturity did differed between males (<1 year) and females (1.6 years). Estimated natural mortality was 0.35 yr−1 decreasing exponentially with age. The results indicate that this species from the southern Gulf of Mexico has moderate growth, long-lived, and early maturity. These factors should be taken into account in stock assessment models, considering time-variable natural mortality.
{"title":"Age-based life history of Lutjanus analis from the southern Gulf of Mexico","authors":"Andy Manuel Escalante-Domínguez , Ximena Renán , Gabriela Galindo-Cortes , Teresa Colás-Marrufo , Thierry Brulé","doi":"10.1016/j.fishres.2025.107646","DOIUrl":"10.1016/j.fishres.2025.107646","url":null,"abstract":"<div><div>Obtaining data on the population structure of <em>Lutjanus analis</em> is crucial, as species with low to moderate growth tend to decline faster with fishing pressure. Even though <em>Lutjanus analis</em> is an economically important species in the southern Gulf of Mexico, age-based life history parameters and the selection of the optimal growth model from three possible (von Bertalanffy, Gompertz, and logistic) were acquired for the first time. Collections were done by the semi-industrial and artisanal fishing fleets from January 2018 to July 2023 (n = 433; FL = 19.0 – 79.3 cm, TW = 0.13 – 9.10 kg). Marginal increment analysis confirmed annulus formation from March to June. Age ranged from 0<sup>+</sup> to 28 years, with the most frequent ages between 4 – 5 years. The von Bertalanffy growth model was the most efficient to describe growth (L<sub>∞</sub> = 76.08 cm, K = 0.17 yr<sup>−1</sup>, t<sub>0</sub> = −1.57). Estimated lifespan was 16.07 years. There were no statistical differences in growth trajectories between sexes. Nevertheless, age at sexual maturity did differed between males (<1 year) and females (1.6 years). Estimated natural mortality was 0.35 yr<sup>−1</sup> decreasing exponentially with age. The results indicate that this species from the southern Gulf of Mexico has moderate growth, long-lived, and early maturity. These factors should be taken into account in stock assessment models, considering time-variable natural mortality.</div></div>","PeriodicalId":50443,"journal":{"name":"Fisheries Research","volume":"293 ","pages":"Article 107646"},"PeriodicalIF":2.3,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145925287","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}
The biological traits of largehead hairtail (Trichiurus japonicus) in the China Seas have undergone pronounced changes, such as smaller body length at age and earlier maturation, which may be attributed to environmental shifts. Consequently, clarifying which environmental variables play a decisive role in the early growth stages of largehead hairtail, along with their impacts, is indispensable for understanding the early life history of this species, and it also holds significant ecological and socio-economic value. To comprehend the variations in early growth of largehead hairtail, we investigated the temporal-scale influences of environmental changes on its early growth. In this study, based on the samples from the East China Sea from 2017 to 2021, the specific relationships between early growth and environmental variables were analyzed by otolith microstructure. Our investigation revealed a notable interannual variability in the early growth of the population. Notably, the sea water temperatures during March and April of 2018 were anomalously lower compared to other years, which corresponded with better growth performance, aided by the reduced Mixed Layer Depth (MLD) during this period. Post-2019, the growth conditions in May were predominantly more conducive for the early growth than in April, leading to a shift in the occurrence of growth peaks to the month of May. This research will provide a foundational understanding of the adaptability of largehead hairtail in the East China Sea in the face of climate change, offering theoretical support for the scientific management of fishery resources.
{"title":"Effects of environmental variables on the interannual variability of early growth of Trichiurus japonicus in the East China Sea","authors":"Fengming Lv, Peng Sun, Guankui Liu, Wenbo Deng, Congxian Chen, Jianchao Li, Yongjun Tian","doi":"10.1016/j.fishres.2026.107652","DOIUrl":"10.1016/j.fishres.2026.107652","url":null,"abstract":"<div><div>The biological traits of largehead hairtail (<em>Trichiurus japonicus</em>) in the China Seas have undergone pronounced changes, such as smaller body length at age and earlier maturation, which may be attributed to environmental shifts. Consequently, clarifying which environmental variables play a decisive role in the early growth stages of largehead hairtail, along with their impacts, is indispensable for understanding the early life history of this species, and it also holds significant ecological and socio-economic value. To comprehend the variations in early growth of largehead hairtail, we investigated the temporal-scale influences of environmental changes on its early growth. In this study, based on the samples from the East China Sea from 2017 to 2021, the specific relationships between early growth and environmental variables were analyzed by otolith microstructure. Our investigation revealed a notable interannual variability in the early growth of the population. Notably, the sea water temperatures during March and April of 2018 were anomalously lower compared to other years, which corresponded with better growth performance, aided by the reduced Mixed Layer Depth (MLD) during this period. Post-2019, the growth conditions in May were predominantly more conducive for the early growth than in April, leading to a shift in the occurrence of growth peaks to the month of May. This research will provide a foundational understanding of the adaptability of largehead hairtail in the East China Sea in the face of climate change, offering theoretical support for the scientific management of fishery resources.</div></div>","PeriodicalId":50443,"journal":{"name":"Fisheries Research","volume":"293 ","pages":"Article 107652"},"PeriodicalIF":2.3,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145976621","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}
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