Pub Date : 2026-02-01DOI: 10.1016/j.jglr.2025.102728
Jonathan D. Midwood , Jill L. Brooks , Paul A. Bzonek , Steven J. Cooke , Melanie V. Croft-White , David T. Reddick , Nicole A. Turner , Sarah Larocque , Caleb T. Hasler
Re-establishment of a naturally reproducing walleye (Sander vitreus) population is a management objective for Hamilton Harbour, western Lake Ontario. Though mature, stocked walleye have been captured during the spawning period on littoral shoals of the harbour, there is no evidence of natural recruitment. Fine-scale walleye positions derived from acoustic telemetry data on a known spawning shoal were aggregated into discrete, presumptive spawning events, where spawning conditions (e.g., Distance to Shore, Movement Rate), timing (e.g., Photoperiod), and their spatio-temporal distribution (e.g., Duration, Kernel Density Estimates) were described. A selection of these metrics were used to characterize seven unique spawning behaviours ranging from spatially focused nearshore events that are consistent with previously described spawning behaviour to short and fast transitory events. The location of some spawning events aligned with areas of high egg deposition, but additional events were found to be deeper and further offshore than expected, but still consistent with other Great Lakes populations. Confirmation of egg deposition at these deeper locations is required as it may indicate a potential remediation measure (i.e., addition of aggregate materials at these depths). The range of behaviours observed is indicative of both individual variation and differential habitat preference for the spawning shoal.
{"title":"Fine-scale behaviour of walleye (Sander vitreus) on a spawning shoal in Hamilton Harbour, Ontario","authors":"Jonathan D. Midwood , Jill L. Brooks , Paul A. Bzonek , Steven J. Cooke , Melanie V. Croft-White , David T. Reddick , Nicole A. Turner , Sarah Larocque , Caleb T. Hasler","doi":"10.1016/j.jglr.2025.102728","DOIUrl":"10.1016/j.jglr.2025.102728","url":null,"abstract":"<div><div>Re-establishment of a naturally reproducing walleye (<em>Sander vitreus</em>) population is a management objective for Hamilton Harbour, western Lake Ontario. Though mature, stocked walleye have been captured during the spawning period on littoral shoals of the harbour, there is no evidence of natural recruitment. Fine-scale walleye positions derived from acoustic telemetry data on a known spawning shoal were aggregated into discrete, presumptive spawning events, where spawning conditions (e.g., Distance to Shore, Movement Rate), timing (e.g., Photoperiod), and their spatio-temporal distribution (e.g., Duration, Kernel Density Estimates) were described. A selection of these metrics were used to characterize seven unique spawning behaviours ranging from spatially focused nearshore events that are consistent with previously described spawning behaviour to short and fast transitory events. The location of some spawning events aligned with areas of high egg deposition, but additional events were found to be deeper and further offshore than expected, but still consistent with other Great Lakes populations. Confirmation of egg deposition at these deeper locations is required as it may indicate a potential remediation measure (i.e., addition of aggregate materials at these depths). The range of behaviours observed is indicative of both individual variation and differential habitat preference for the spawning shoal.</div></div>","PeriodicalId":54818,"journal":{"name":"Journal of Great Lakes Research","volume":"52 1","pages":"Article 102728"},"PeriodicalIF":2.5,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146116320","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-02-01DOI: 10.1016/j.jglr.2026.102751
Freya E. Rowland, Curt G. Byrd, Patrick T. Kroboth
Bighead carp (Hypophthalmichthys nobilis), black carp (Mylopharyngodon piceus), grass carp (Ctenopharyngodon idella), and silver carp (H. molitrix) have spurred wide concern of potential ecosystem disruption as they threaten to invade the Laurentian Great Lakes. Besides competition for resources, carp may also have disadvantageous nutrition for predators. One biochemical aspect to consider in carp is production of the enzyme thiaminase that cleaves thiamine (vitamin B1), making it unavailable to most vertebrates. The function of thiaminase within prey fishes is unclear, but roughly half of all fishes tested have measurable thiaminase activity. Predators consuming large volumes of prey with high thiaminase activity can develop thiamine deficiency, ultimately leading to offspring mortality. Three invasive carp (black carp, grass carp, and bighead carp) have no published thiaminase data. We tested juvenile (<160 mm standard length) black carp (n = 38), bighead carp (n = 7), grass carp (n = 50), and silver carp (n = 50) for thiaminase activity. All four species had measurable activity; however, grass carp had statistically higher thiaminase activity (p < 0.001; median = 61 nmol/g/min) than the other three species. Silver carp had the second highest thiaminase activity (14 nmol/g/min). Bighead (2.7 nmol/g/min) and black (2.2 nmol/g/min) carp had the lowest thiaminase activity; activities were often near detection limits. Predators with diets heavily composed of grass carp or silver carp may experience thiamine deficiency, though seasonal variation in carp size and other food source availability may determine potential effects of invasive carp predation in Great Lakes food webs.
{"title":"Thiaminase I activity is high in grass and silver carp, but negligible in bighead and black carp","authors":"Freya E. Rowland, Curt G. Byrd, Patrick T. Kroboth","doi":"10.1016/j.jglr.2026.102751","DOIUrl":"10.1016/j.jglr.2026.102751","url":null,"abstract":"<div><div>Bighead carp (<em>Hypophthalmichthys nobilis</em>), black carp (<em>Mylopharyngodon piceus</em>), grass carp (<em>Ctenopharyngodon idella</em>), and silver carp (<em>H. molitrix</em>) have spurred wide concern of potential ecosystem disruption as they threaten to invade the Laurentian Great Lakes. Besides competition for resources, carp may also have disadvantageous nutrition for predators. One biochemical aspect to consider in carp is production of the enzyme thiaminase that cleaves thiamine (vitamin B<sub>1</sub>), making it unavailable to most vertebrates. The function of thiaminase within prey fishes is unclear, but roughly half of all fishes tested have measurable thiaminase activity. Predators consuming large volumes of prey with high thiaminase activity can develop thiamine deficiency, ultimately leading to offspring mortality. Three invasive carp (black carp, grass carp, and bighead carp) have no published thiaminase data. We tested juvenile (<160 mm standard length) black carp (n = 38), bighead carp (n = 7), grass carp (n = 50), and silver carp (n = 50) for thiaminase activity. All four species had measurable activity; however, grass carp had statistically higher thiaminase activity (p < 0.001; median = 61 nmol/g/min) than the other three species. Silver carp had the second highest thiaminase activity (14 nmol/g/min). Bighead (2.7 nmol/g/min) and black (2.2 nmol/g/min) carp had the lowest thiaminase activity; activities were often near detection limits. Predators with diets heavily composed of grass carp or silver carp may experience thiamine deficiency, though seasonal variation in carp size and other food source availability may determine potential effects of invasive carp predation in Great Lakes food webs.</div></div>","PeriodicalId":54818,"journal":{"name":"Journal of Great Lakes Research","volume":"52 1","pages":"Article 102751"},"PeriodicalIF":2.5,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146116363","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-02-01DOI: 10.1016/j.jglr.2025.102703
Cooper O’Rourke, Alex Smith, Jacqueline Voisin-Roewade, Chris Houser
Increasing shoreline development, changes in water levels, storm activity, and reduced lake ice has resulted in accelerated shoreline erosion around the Laurentian Great Lakes (LGL). Along the northern shore of Lake Erie, retreat of glacial bluffs threatens sensitive habitats, infrastructure, and personal property. This study quantifies the extent of modern shoreline change and bluff retreat along 186 km of beach and 109 km of bluffs in the north central basin of Lake Erie between 2006 and 2020. Shoreline change and bluff retreat were quantified using imagery from the Southwestern Ontario Orthophotography Project (SWOOP) and digital elevation model datasets for 2006, 2010, 2015, and 2020. Results suggest that the average rate of bluff toe and brink retreat were −1.75 m y-1 and −1.56 m y-1, respectively, but with significant variation in retreat alongshore and in response to variations in water level. The corresponding alongshore average annual volumetric loss from the bluffs was 43.23 × 105 m3 y-1. Over the same period, a total of ∼ 2.6 × 106 m3 y-1 of sediment was lost on the updrift side of the jetties, suggesting that jetties are at capacity and that sediment is bypassing them. Despite the liberation of large amounts of sediment from the bluffs and from behind the jetties, the shoreline continued to erode along the distal spits, suggesting that sediment is being transported offshore or beyond the distal ends of the spits. Further study is required to determine the current and future fate of the bluff sediment as part of a regional sediment budget.
海岸线的不断发展、水位的变化、风暴活动和湖冰的减少导致了劳伦森五大湖(LGL)周围海岸线的加速侵蚀。沿着伊利湖北岸,冰川悬崖的退缩威胁着敏感的栖息地、基础设施和个人财产。这项研究量化了2006年至2020年间伊利湖中北部盆地186公里海滩和109公里悬崖的现代海岸线变化和断崖退缩的程度。利用2006年、2010年、2015年和2020年安大略省西南正射影摄影项目(SWOOP)和数字高程模型数据集的图像,对海岸线变化和断崖退缩进行了量化。结果表明,崖尖和边缘退缩的平均速率分别为- 1.75 m y-1和- 1.56 m y-1,但沿岸退缩和水位变化有显著差异。相应的沿岸断崖年平均体积损失为43.23 × 105 m3 y-1。在同一时期,在防波堤的上升流侧总共损失了~ 2.6 × 106 m3 y-1的泥沙,这表明防波堤处于饱和状态,泥沙正在绕过它们。尽管从悬崖和防波堤后面释放了大量沉积物,但沿着远端喷口的海岸线继续受到侵蚀,这表明沉积物正在被运往离岸或超出远端喷口。作为区域泥沙收支的一部分,需要进一步的研究来确定崖状沉积物现在和未来的命运。
{"title":"Rates of bluff retreat and shoreline change along the north shore of Lake Erie","authors":"Cooper O’Rourke, Alex Smith, Jacqueline Voisin-Roewade, Chris Houser","doi":"10.1016/j.jglr.2025.102703","DOIUrl":"10.1016/j.jglr.2025.102703","url":null,"abstract":"<div><div>Increasing shoreline development, changes in water levels, storm activity, and reduced lake ice has resulted in accelerated shoreline erosion around the Laurentian Great Lakes (LGL). Along the northern shore of Lake Erie, retreat of glacial bluffs threatens sensitive habitats, infrastructure, and personal property. This study quantifies the extent of modern shoreline change and bluff retreat along 186 km of beach and 109 km of bluffs in the north central basin of Lake Erie between 2006 and 2020. Shoreline change and bluff retreat were quantified using imagery from the Southwestern<!--> <!-->Ontario Orthophotography Project (SWOOP) and digital elevation model datasets for 2006, 2010, 2015, and 2020. Results suggest that the average rate of bluff toe and brink retreat were −1.75 m y<sup>-1</sup> and −1.56 m y<sup>-1</sup>, respectively, but with significant variation in retreat alongshore and in response to variations in water level. The corresponding alongshore average annual volumetric loss from the bluffs was 43.23 × 10<sup>5</sup> m<sup>3</sup> y<sup>-1</sup>. Over the same period, a total of ∼ 2.6 × 10<sup>6</sup> m<sup>3</sup> y<sup>-1</sup> of sediment was lost on the updrift side of the jetties, suggesting that jetties are at capacity and that sediment is bypassing them. Despite the liberation of large amounts of sediment from the bluffs and from behind the jetties, the shoreline continued to erode along the distal spits, suggesting that sediment is being transported offshore or beyond the distal ends of the spits. Further study is required to determine the current and future fate of the bluff sediment as part of a regional sediment budget.</div></div>","PeriodicalId":54818,"journal":{"name":"Journal of Great Lakes Research","volume":"52 1","pages":"Article 102703"},"PeriodicalIF":2.5,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146116360","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-02-01DOI: 10.1016/j.jglr.2026.102742
Tyler J. Harrow-Lyle , David C. Depew , Shuqi Lin , Diana Fred , Chris Herc , Andrew J. Bramburger , Mohamed N. Mohamed
Lake of the Woods (LotW) is a large, morphologically complex water body shared between Indigenous communities, Canada, and the US with a history of eutrophication and harmful algal blooms (HABs). The highly variable geology and landscape composition (e.g., peatlands, forest, Canadian Shield) across the LotW basin complement the hydrological complexity of the lake. In an effort to ameliorate the frequency and severity of cyanobacterial harmful algal blooms (cHABs), extensive field collections and modelling efforts have been undertaken to develop adaptive management plans for LotW. However, prior modelling efforts have assumed that the Rainy River watershed is the dominant source of nutrients to LotW. In this study, we used long-term water quality observations from 2008 to 2024 collected by Environment and Climate Change Canada to develop a Bayesian structural equation model, one which allowed us to assess the drivers of in-lake nutrients and chlorophyll. While our results indicate that Rainy River load reductions will improve conditions in the southern basins, these load reductions may not affect conditions in the northerly basins. This work illustrates that future research is required to capture the drivers of phosphorus and nitrogen across LotW which result in cHAB development, to ultimately produce appropriate management strategies for the system.
{"title":"Assessing nutrient and chlorophyll drivers in Lake of the Woods: A complex system shared among Indigenous communities, Canada, and the USA","authors":"Tyler J. Harrow-Lyle , David C. Depew , Shuqi Lin , Diana Fred , Chris Herc , Andrew J. Bramburger , Mohamed N. Mohamed","doi":"10.1016/j.jglr.2026.102742","DOIUrl":"10.1016/j.jglr.2026.102742","url":null,"abstract":"<div><div>Lake of the Woods (LotW) is a large, morphologically complex water body shared between Indigenous communities, Canada, and the US with a history of eutrophication and harmful algal blooms (HABs). The highly variable geology and landscape composition (e.g., peatlands, forest, Canadian Shield) across the LotW basin complement the hydrological complexity of the lake. In an effort to ameliorate the frequency and severity of cyanobacterial harmful algal blooms (cHABs), extensive field collections and modelling efforts have been undertaken to develop adaptive management plans for LotW. However, prior modelling efforts have assumed that the Rainy River watershed is the dominant source of nutrients to LotW. In this study, we used long-term water quality observations from 2008 to 2024 collected by Environment and Climate Change Canada to develop a Bayesian structural equation model, one which allowed us to assess the drivers of in-lake nutrients and chlorophyll. While our results indicate that Rainy River load reductions will improve conditions in the southern basins, these load reductions may not affect conditions in the northerly basins. This work illustrates that future research is required to capture the drivers of phosphorus and nitrogen across LotW which result in cHAB development, to ultimately produce appropriate management strategies for the system.</div></div>","PeriodicalId":54818,"journal":{"name":"Journal of Great Lakes Research","volume":"52 1","pages":"Article 102742"},"PeriodicalIF":2.5,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146116503","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-02-01DOI: 10.1016/j.jglr.2025.102738
Isaac Armstrong , Emma L. Graves , Jamie A. Would , Iza Pawlowski , Brian F. Cumming
Aquatic food webs in the Laurentian Great Lakes are impacted by the legacy effects of twentieth-century land-use change and nutrient enrichment which co-occur with climate warming and invasive species. Zooplankton populations are currently degraded in the Bay of Quinte Area of Concern, Lake Ontario, which experienced cultural hypereutrophication by the 1950 s and the invasion of dreissenid mussels c. 1994. A drop in pelagic productivity was noted in 2013, raising concerns for fisheries. We examined Cladocera (Crustacea: Branchiopoda) remains in four dated sediment cores from the Bay of Quinte to assess food-web response to historic stressors. We characterized long-term trends in cladoceran abundance, composition, and Bosmina spp. mucro length (as a proxy for zooplanktivory). The largest assemblage change occurred with early 1900 s eutrophication: concentrations of B. longirostris and Chydorus sphaericus increased sharply while Daphnia longispina complex concentrations and littoral diversity declined. Minor declines in concentrations of eutrophication-associated taxa co-occurred with nutrient abatement actions, while dreissenid establishment was associated with increased zooplanktivory in the shallow Upper Bay but decreased zooplanktivory in the deeper Middle Bay. Modern-day assemblages are distinct from pre-eutrophication assemblages, especially as invasive Eubosmina coregoni is abundant, and inferred fish planktivory is elevated relative to historic conditions. Observed declines in pelagic productivity c. 2013 coincided with increases in littoral taxa and a continued depression of large pelagic grazer Daphnia, indicating a potential shift to littoral production, and suggesting that dreissenids and climate warming may contribute to altered food-web dynamics.
{"title":"Impacts of hypereutrophication and aquatic invasive species on cladoceran dynamics in the Bay of Quinte Area of Concern, Lake Ontario","authors":"Isaac Armstrong , Emma L. Graves , Jamie A. Would , Iza Pawlowski , Brian F. Cumming","doi":"10.1016/j.jglr.2025.102738","DOIUrl":"10.1016/j.jglr.2025.102738","url":null,"abstract":"<div><div>Aquatic food webs in the Laurentian Great Lakes are impacted by the legacy effects of twentieth-century land-use change and nutrient enrichment which co-occur with climate warming and invasive species. Zooplankton populations are currently degraded in the Bay of Quinte Area of Concern, Lake Ontario, which experienced cultural hypereutrophication by the 1950 s and the invasion of dreissenid mussels c. 1994. A drop in pelagic productivity was noted in 2013, raising concerns for fisheries. We examined Cladocera (Crustacea: Branchiopoda) remains in four dated sediment cores from the Bay of Quinte to assess food-web response to historic stressors. We characterized long-term trends in cladoceran abundance, composition, and <em>Bosmina</em> spp. mucro length (as a proxy for zooplanktivory). The largest assemblage change occurred with early 1900 s eutrophication: concentrations of <em>B. longirostris</em> and <em>Chydorus sphaericus</em> increased sharply while <em>Daphnia longispina</em> complex concentrations and littoral diversity declined. Minor declines in concentrations of eutrophication-associated taxa co-occurred with nutrient abatement actions, while dreissenid establishment was associated with increased zooplanktivory in the shallow Upper Bay but decreased zooplanktivory in the deeper Middle Bay. Modern-day assemblages are distinct from pre-eutrophication assemblages, especially as invasive <em>Eubosmina coregoni</em> is abundant, and inferred fish planktivory is elevated relative to historic conditions. Observed declines in pelagic productivity c. 2013 coincided with increases in littoral taxa and a continued depression of large pelagic grazer <em>Daphnia</em>, indicating a potential shift to littoral production, and suggesting that dreissenids and climate warming may contribute to altered food-web dynamics.</div></div>","PeriodicalId":54818,"journal":{"name":"Journal of Great Lakes Research","volume":"52 1","pages":"Article 102738"},"PeriodicalIF":2.5,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146116504","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-02-01DOI: 10.1016/j.jglr.2026.102746
Maxwell L. Wilder , John M. Farrell, Hyatt C. Green
Sensitive detection methods are critical for fisheries conservation and management. We compare environmental DNA (eDNA) detection methods with live capture techniques for monitoring muskellunge (Esox masquinongy) in the St. Lawrence River, where populations are impacted by habitat loss and disease. eDNA sampling was performed alongside three surveys: 1) trap netting for adult muskellunge in spawning bays, 2) 30-ft (9.1 m) seining for young-of-year (YOY) muskellunge in nursery habitat, and 3) 60-ft (18.2 m) seining for YOY muskellunge in the same nursery habitat. Additionally, eDNA was collected both before and 1-week following muskellunge fry stocking to assess how an influx of fry impacts near-term eDNA detection. Our results demonstrate that eDNA analysis outperforms trap netting for identifying muskellunge presence in spawning bays, with 11 of 12 bays containing detectable eDNA versus only three bays yielding live captures. In seining surveys, eDNA detection closely mirrored live capture success, and a significant positive correlation was observed between eDNA detection and catch per unit effort (CPUE). In our assessment of near-term eDNA concentrations following fry stocking, we observed lower detectability after fry introduction, possibly due to environmental factors and low muskellunge biomass. While most eDNA samples were below the quantification limit, preventing abundance estimates, this work highlights the potential of eDNA detection as a screening approach for evaluating muskellunge presence. Our results suggest eDNA detection could complement traditional surveys, potentially improving efficiency by identifying priority sites for resource-intensive live capture efforts. Our results also highlight the need for methodological enhancements for eDNA quantification for low-density species.
{"title":"Comparing environmental DNA (eDNA) and live capture methods for detecting muskellunge (Esox masquinongy) in the St. Lawrence River","authors":"Maxwell L. Wilder , John M. Farrell, Hyatt C. Green","doi":"10.1016/j.jglr.2026.102746","DOIUrl":"10.1016/j.jglr.2026.102746","url":null,"abstract":"<div><div>Sensitive detection methods are critical for fisheries conservation and management. We compare environmental DNA (eDNA) detection methods with live capture techniques for monitoring muskellunge (<em>Esox masquinongy</em>) in the St. Lawrence River, where populations are impacted by habitat loss and disease. eDNA sampling was performed alongside three surveys: 1) trap netting for adult muskellunge in spawning bays, 2) 30-ft (9.1 m) seining for young-of-year (YOY) muskellunge in nursery habitat, and 3) 60-ft (18.2 m) seining for YOY muskellunge in the same nursery habitat. Additionally, eDNA was collected both before and 1-week following muskellunge fry stocking to assess how an influx of fry impacts near-term eDNA detection. Our results demonstrate that eDNA analysis outperforms trap netting for identifying muskellunge presence in spawning bays, with 11 of 12 bays containing detectable eDNA versus only three bays yielding live captures. In seining surveys, eDNA detection closely mirrored live capture success, and a significant positive correlation was observed between eDNA detection and catch per unit effort (CPUE). In our assessment of near-term eDNA concentrations following fry stocking, we observed lower detectability after fry introduction, possibly due to environmental factors and low muskellunge biomass. While most eDNA samples were below the quantification limit, preventing abundance estimates, this work highlights the potential of eDNA detection as a screening approach for evaluating muskellunge presence. Our results suggest eDNA detection could complement traditional surveys, potentially improving efficiency by identifying priority sites for resource-intensive live capture efforts. Our results also highlight the need for methodological enhancements for eDNA quantification for low-density species.</div></div>","PeriodicalId":54818,"journal":{"name":"Journal of Great Lakes Research","volume":"52 1","pages":"Article 102746"},"PeriodicalIF":2.5,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146116362","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We conducted an exploratory study to quantify major and trace elements in the pectoral fin spines of two species of endangered sturgeons (Acipenser gueldenstaedtii, A. nudiventris) from the southern Caspian Sea and one catfish species (Silurus glanis) from the Anzali Lagoon. Using inductively coupled plasma mass spectrometer (ICP-MS), we measured 66 elements and applied Orthogonal Partial Least Squares (OPLS) analysis to describe interspecific variability in elemental profiles. The model separated the species, and a subset of metals (e.g., Cu, Zn, Mn, Pb) accounted for most of the discrimination; targeted univariate tests confirmed higher concentrations of several elements in S. glanis. Notably, the anadromous sturgeons sampled along the Caspian coast likely integrate exposure across brackish–freshwater gradients during migrations to rivers or wetlands, whereas S. glanis represents a resident population in Anzali Lagoon. Because our design couples species and location, even with the higher concentrations observed in S. glanis, we do not make causal attributions about possible contamination sources. We interpret the patterns as consistent with species- and habitat-specific exposure and life-history differences, and we highlight fin spines as a nonlethal matrix that captures informative elemental signatures. These results provide a baseline and guide future sampling comparing the same species across locations to evaluate exposure in threatened sturgeon populations.
我们对里海南部的两种濒危鲟鱼(acpenser gueldenstaedtii, A. nudiventris)和安扎利泻湖的一种鲶鱼(Silurus glanis)胸鳍棘中的主要元素和微量元素进行了探索性研究。利用电感耦合等离子体质谱(ICP-MS)测量了66种元素,并应用正交偏最小二乘(OPLS)分析来描述元素谱的种间变异。该模型对物种进行了分类,其中Cu、Zn、Mn、Pb等金属的分类占大部分;目标单变量试验证实了葡萄中几种元素的浓度较高。值得注意的是,在里海沿岸取样的溯河鲟可能在迁徙到河流或湿地的过程中经历了咸淡淡水梯度的暴露,而S. glanis则代表了安扎利泻湖的常住种群。由于我们的设计结合了物种和位置,即使在S. glanis中观察到较高的浓度,我们也没有对可能的污染源进行因果归因。我们将这种模式解释为与物种和栖息地特定暴露和生活史差异一致,并且我们强调鳍刺是非致命的基质,可以捕获信息元素特征。这些结果提供了一个基线,并指导未来的采样,比较不同地点的同一物种,以评估受威胁鲟鱼种群的暴露情况。
{"title":"Bioaccumulation of major and trace elements in pectoral fin spines of sturgeons and catfish from the southern Caspian Sea and Anzali Lagoon","authors":"Shima Bakhshalizadeh , Keyvan Abbasi , Rafael Mora-Medina , Nahúm Ayala-Soldado","doi":"10.1016/j.jglr.2026.102749","DOIUrl":"10.1016/j.jglr.2026.102749","url":null,"abstract":"<div><div>We conducted an exploratory study to quantify major and trace elements in the pectoral fin spines of two species of endangered sturgeons (<em>Acipenser gueldenstaedtii</em>, <em>A. nudiventris</em>) from the southern Caspian Sea and one catfish species (<em>Silurus glanis</em>) from the Anzali Lagoon. Using inductively coupled plasma mass spectrometer (ICP-MS), we measured 66 elements and applied Orthogonal Partial Least Squares (OPLS) analysis to describe interspecific variability in elemental profiles. The model separated the species, and a subset of metals (e.g., Cu, Zn, Mn, Pb) accounted for most of the discrimination; targeted univariate tests confirmed higher concentrations of several elements in <em>S. glanis</em>. Notably, the anadromous sturgeons sampled along the Caspian coast likely integrate exposure across brackish–freshwater gradients during migrations to rivers or wetlands, whereas <em>S. glanis</em> represents a resident population in Anzali Lagoon. Because our design couples species and location, even with the higher concentrations observed in <em>S. glanis</em>, we do not make causal attributions about possible contamination sources. We interpret the patterns as consistent with species- and habitat-specific exposure and life-history differences, and we highlight fin spines as a nonlethal matrix that captures informative elemental signatures. These results provide a baseline and guide future sampling comparing the same species across locations to evaluate exposure in threatened sturgeon populations.</div></div>","PeriodicalId":54818,"journal":{"name":"Journal of Great Lakes Research","volume":"52 1","pages":"Article 102749"},"PeriodicalIF":2.5,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146116383","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-02-01DOI: 10.1016/j.jglr.2025.102733
Trudy Watson-Leung, Lisa Kennedy, David G. Poirier
Ontario’s Municipal/Industrial Strategy for Abatement (MISA) was a collaborative effort between government and industry to reduce the environmental impacts of effluents through monitoring, BATEA (best available technologies economically achievable) and regulations. From 1988 to 1993, chemical and toxicity testing of effluents directly discharged to the environment was conducted. Nine industrial sectors represented ∼70 % of the direct dischargers in Ontario at the time. Monitoring and testing of facilities from these sectors led to the development of the Effluent Monitoring and Effluent Limits (EMEL) regulatory compliance limits. This article outlines the history of this successful collaborative strategy between government and industry and reviews almost 30 years of paired standardized acute aquatic toxicity data with the fish species rainbow trout (RT) (Oncorhynchus mykiss) and the invertebrate Daphnia magna (DM), before and after the implementation of EMEL compliance limits. Acute toxicity testing completed before implementation of the EMEL regulations indicated that 41 % of all effluent samples (n = 3371) caused > 50 % mortality in RT and DM. Following the implementation of various regulations, program, and compliance initiatives (1995–2015), acute toxicity in all sectors was reduced by 77 % in DM and 80 % in RT (n = 22,222 effluent samples). Analysis of compliance toxicity data indicated that DM testing alone would have been sufficient (in 99 % of samples) to predict RT toxicity. The collaborative MISA/EMEL approach to pollution reduction led to a significant decrease in acute toxicity in Ontario industrial effluents and provides data that could inform the conversation around the reduction of vertebrate use in acute toxicity assessments of industrial effluent.
{"title":"28-Year review of acute toxicity in rainbow trout and Daphnia magna exposed to industrial effluents in Ontario, Canada","authors":"Trudy Watson-Leung, Lisa Kennedy, David G. Poirier","doi":"10.1016/j.jglr.2025.102733","DOIUrl":"10.1016/j.jglr.2025.102733","url":null,"abstract":"<div><div>Ontario’s Municipal/Industrial Strategy for Abatement (MISA) was a collaborative effort between government and industry to reduce the environmental impacts of effluents through monitoring, BATEA (best available technologies economically achievable) and regulations. From 1988 to 1993, chemical and toxicity testing of effluents directly discharged to the environment was conducted. Nine industrial sectors represented ∼70 % of the direct dischargers in Ontario at the time. Monitoring and testing of facilities from these sectors led to the development of the Effluent Monitoring and Effluent Limits (EMEL) regulatory compliance limits. This article outlines the history of this successful collaborative strategy between government and industry and reviews almost 30 years of paired standardized acute aquatic toxicity data with the fish species rainbow trout (RT) (<em>Oncorhynchus mykiss</em>) and the invertebrate <em>Daphnia magna</em> (DM), before and after the implementation of EMEL compliance limits. Acute toxicity testing completed before implementation of the EMEL regulations indicated that 41 % of all effluent samples (n = 3371) caused > 50 % mortality in RT and DM. Following the implementation of various regulations, program, and compliance initiatives (1995–2015), acute toxicity in all sectors was reduced by 77 % in DM and 80 % in RT (n = 22,222 effluent samples). Analysis of compliance toxicity data indicated that DM testing alone would have been sufficient (in 99 % of samples) to predict RT toxicity. The collaborative MISA/EMEL approach to pollution reduction led to a significant decrease in acute toxicity in Ontario industrial effluents and provides data that could inform the conversation around the reduction of vertebrate use in acute toxicity assessments of industrial effluent.</div></div>","PeriodicalId":54818,"journal":{"name":"Journal of Great Lakes Research","volume":"52 1","pages":"Article 102733"},"PeriodicalIF":2.5,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146116380","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-02-01DOI: 10.1016/j.jglr.2026.102745
Hannes Waldetoft , M. Gunnar Andersson , Joakim Hållén , Hans Nyquist , Martin Ogonowski , O. Magnus Karlsson
Whitefish (Coregonus sp.) are an ecologically and economically important species in large, temperate lake ecosystems, including North America’s Laurentian Great Lakes. While levels of persistent organic pollutants have generally declined in many large-lake systems, unexpectedly high concentrations of polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDDFs), and biphenyls (PCBs) have been detected in whitefish from Sweden’s two largest lakes, Vänern and Vättern, prompting an extensive investigation. This study analyzed 282 whitefish samples collected between 2015 and 2022 from these lakes and from the Gulf of Bothnia—a large, brackish basin of the Baltic Sea known for long-standing contamination issues. Whitefish dorsal muscle tissue was collected from commercial catches and analyzed to quantify the contaminant levels. We used generalized linear models to assess which spatial, temporal, and morphometric variables explained variation in toxic equivalent (TEQ) levels. While whitefish from Lake Vänern had higher contaminant levels than those from oligotrophic Lake Vättern, this difference was largely explained by their higher fat content. The total length was positively associated with TEQ, while the condition factor showed a negative association in Lake Vättern whitefish, suggesting a greater mobilization of contaminants from lipids to muscle due to starvation-related effects. Similar to recent observations in some Laurentian Great Lakes, we found no significant temporal decline in TEQ during the study period. Our findings provide a European large-lake perspective on the complex factors governing contaminant bioaccumulation in a key fish species, offering valuable comparative insights for Great Lakes science and management.
{"title":"Fat content and condition factor explain levels of dioxins and PCBs in whitefish (Coregonus sp.) from Sweden’s major lakes","authors":"Hannes Waldetoft , M. Gunnar Andersson , Joakim Hållén , Hans Nyquist , Martin Ogonowski , O. Magnus Karlsson","doi":"10.1016/j.jglr.2026.102745","DOIUrl":"10.1016/j.jglr.2026.102745","url":null,"abstract":"<div><div>Whitefish (<em>Coregonus</em> sp.) are an ecologically and economically important species in large, temperate lake ecosystems, including North America’s Laurentian Great Lakes. While levels of persistent organic pollutants have generally declined in many large-lake systems, unexpectedly high concentrations of polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDDFs), and biphenyls (PCBs) have been detected in whitefish from Sweden’s two largest lakes, Vänern and Vättern, prompting an extensive investigation. This study analyzed 282 whitefish samples collected between 2015 and 2022 from these lakes and from the Gulf of Bothnia—a large, brackish basin of the Baltic Sea known for long-standing contamination issues. Whitefish dorsal muscle tissue was collected from commercial catches and analyzed to quantify the contaminant levels. We used generalized linear models to assess which spatial, temporal, and morphometric variables explained variation in toxic equivalent (TEQ) levels. While whitefish from Lake Vänern had higher contaminant levels than those from oligotrophic Lake Vättern, this difference was largely explained by their higher fat content. The total length was positively associated with TEQ, while the condition factor showed a negative association in Lake Vättern whitefish, suggesting a greater mobilization of contaminants from lipids to muscle due to starvation-related effects. Similar to recent observations in some Laurentian Great Lakes, we found no significant temporal decline in TEQ during the study period. Our findings provide a European large-lake perspective on the complex factors governing contaminant bioaccumulation in a key fish species, offering valuable comparative insights for Great Lakes science and management.</div></div>","PeriodicalId":54818,"journal":{"name":"Journal of Great Lakes Research","volume":"52 1","pages":"Article 102745"},"PeriodicalIF":2.5,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146116381","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-02-01DOI: 10.1016/j.jglr.2025.102734
Rui Li , Wengang Kang , Guangjie Chen , Li Chen , Shuaiying Zhao , Xiaolin Chen , Tao Zhang
Thermal and nutrient fluctuations are known to determine ecological structure in shallow lakes. However, their forcing on algal assembly in large and deep lakes remains largely unclear in subtropical regions. Here, a monthly survey was conducted in 2015 to examine the mechanisms for epilimnetic diatom assembly across 16 sites of Fuxian Lake in subtropical China. In this deep system (maximum depth 158.9 m), there existed a clear seasonality in the dominant diatoms, shifting from colonial Fragilaria crotonensis (January–February) to heavily silicified Aulacoseira granulata (March–April), before small-sized Pantocsekiella ocellata predominated (> 50 %) from May to December when thermal stability was strong. While species turnover over time was notable (2.07 ± 0.18 SD, n = 16) and driven by nutrient and thermal factors (55.0 % variance), spatial species turnover was lower (1.10 ± 0.22 SD, n = 12), and nutrient and thermal factors explained much less variance (14.3 %). Specifically, temperature and nutrients independently explained 24.1 % and 17.6 % of the temporal variation, respectively, with a strong interaction (13.3 %). Structural equation modeling (SEM) further suggested that strong thermal stability, enhanced by rising temperature and reduced wind speed, may have significantly shaped diatom assembly. Additionally, rising stability was associated with decreased epilimnetic nutrient concentrations, possibly due to a weaker exchange with bottom-water, which can inhibit diatoms with high nutrient demands. Overall, our in situ observational evidence indicates that thermal stability governs seasonal succession of diatom communities and also interacts with fluctuating nutrients, suggesting that continued warming may seasonally enhance lake-water thermal stability and intensify species turnover in deep subtropical lakes.
众所周知,热量和营养的波动决定了浅湖的生态结构。然而,在亚热带地区,它们对大而深的湖泊中藻类聚集的影响在很大程度上仍不清楚。在此,我们于2015年进行了一项月度调查,以研究中国亚热带抚仙湖16个地点的epilimnetic硅藻组装机制。在该深层系统(最大深度158.9 m)中,优势硅藻有明显的季节性,从殖民地的碎碎藻(Fragilaria crotonensis)(1 - 2月)到重硅化的细粒藻(Aulacoseira granulata)(3 - 4月),在热稳定性较强的5 - 12月,小硅藻(Pantocsekiella ocellata)占主导地位(50%)。物种在时间上的更替显著(2.07±0.18 SD, n = 16),由养分和热因子驱动(55.0%方差),但空间上的更替较小(1.10±0.22 SD, n = 12),养分和热因子对变异的解释较小(14.3%)。具体来说,温度和养分分别独立解释了24.1%和17.6%的时间变化,并有很强的相互作用(13.3%)。结构方程模型(SEM)进一步表明,由于温度升高和风速降低而增强的强热稳定性可能对硅藻的组装有显著影响。此外,稳定性的提高与海底营养浓度的降低有关,这可能是由于与底水的交换较弱,这可能会抑制高营养需求的硅藻。总体而言,我们的原位观测证据表明,热稳定性控制着硅藻群落的季节演替,并与波动的营养物质相互作用,表明持续变暖可能季节性地增强亚热带深层湖泊的湖-水热稳定性并加剧物种更替。
{"title":"Thermal stability overrides epilimnetic nutrient availability in diatom seasonality in a deep lake of subtropical China","authors":"Rui Li , Wengang Kang , Guangjie Chen , Li Chen , Shuaiying Zhao , Xiaolin Chen , Tao Zhang","doi":"10.1016/j.jglr.2025.102734","DOIUrl":"10.1016/j.jglr.2025.102734","url":null,"abstract":"<div><div>Thermal and nutrient fluctuations are known to determine ecological structure in shallow lakes. However, their forcing on algal assembly in large and deep lakes remains largely unclear in subtropical regions. Here, a monthly survey was conducted in 2015 to examine the mechanisms for epilimnetic diatom assembly across 16 sites of Fuxian Lake in subtropical China. In this deep system (maximum depth 158.9 m), there existed a clear seasonality in the dominant diatoms, shifting from colonial <em>Fragilaria crotonensis</em> (January–February) to heavily silicified <em>Aulacoseira granulata</em> (March–April), before small-sized <em>Pantocsekiella ocellata</em> predominated (> 50 %) from May to December when thermal stability was strong. While species turnover over time was notable (2.07 ± 0.18 SD, n = 16) and driven by nutrient and thermal factors (55.0 % variance), spatial species turnover was lower (1.10 ± 0.22 SD, n = 12), and nutrient and thermal factors explained much less variance (14.3 %). Specifically, temperature and nutrients independently explained 24.1 % and 17.6 % of the temporal variation, respectively, with a strong interaction (13.3 %). Structural equation modeling (SEM) further suggested that strong thermal stability, enhanced by rising temperature and reduced wind speed, may have significantly shaped diatom assembly. Additionally, rising stability was associated with decreased epilimnetic nutrient concentrations, possibly due to a weaker exchange with bottom-water, which can inhibit diatoms with high nutrient demands. Overall, our in situ observational evidence indicates that thermal stability governs seasonal succession of diatom communities and also interacts with fluctuating nutrients, suggesting that continued warming may seasonally enhance lake-water thermal stability and intensify species turnover in deep subtropical lakes.</div></div>","PeriodicalId":54818,"journal":{"name":"Journal of Great Lakes Research","volume":"52 1","pages":"Article 102734"},"PeriodicalIF":2.5,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146116385","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}