Journal of Great Lakes Research最新文献

{"title":"Hydrologic connections in Apostle Islands coastal wetlands: Exploring dynamics and resilience to Lake Superior water level fluctuations","authors":"Olivia C. Anderson,&nbsp;Sarah E. Johnson,&nbsp;Shea Schachameyer,&nbsp;Shelly L. Ray,&nbsp;Matthew J. Cooper","doi":"10.1016/j.jglr.2025.102538","DOIUrl":"10.1016/j.jglr.2025.102538","url":null,"abstract":"<div><div>Coastal wetlands within Apostle Islands National Lakeshore (APIS) represent important reference ecosystems for Lake Superior given their relatively undegraded condition. However, this region lacks climate change-relevant nearshore bathymetric information for coastal wetlands, a gap our study helps fill. Since 2010, the Great Lakes, including Lake Superior, have experienced both extended low water levels and extreme highs. Such extremes are anticipated to increase in frequency and duration, but the exact outcomes are uncertain. Therefore, it is important to explore the resiliency of APIS wetlands against different water level scenarios. We studied seven wetlands with different geomorphic connections to Lake Superior (open, transient, or semi-permanent) and gathered water level and depth data. Using depth measurements, we created topo-bathymetric maps to investigate inundation patterns for various scenarios of Lake Superior water levels. Comparing wetland water levels to those of Lake Superior we found that water level patterns were unique per connection type, but that Lake Superior maintained baseline-water levels for all sites. Additionally, the wetlands we sampled demonstrated resiliency to substantial changes in water levels thanks to both bathymetry deeper than record low Lake Superior levels and sufficient undisturbed upslope habitats. However, the biotic communities within could shift in composition depending on future water level regimes. The increasing magnitude and frequency of Great Lakes water level fluctuations induced by climate change will influence all APIS coastal wetlands, regardless of connection type.</div></div>","PeriodicalId":54818,"journal":{"name":"Journal of Great Lakes Research","volume":"51 2","pages":"Article 102538"},"PeriodicalIF":2.4,"publicationDate":"2025-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143631821","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}

{"title":"Long-term trends in particulate nutrients in offshore waters of the Laurentian Great Lakes","authors":"Erica P. Yang ,&nbsp;Anne M. Scofield ,&nbsp;Matthew B. Pawlowski","doi":"10.1016/j.jglr.2025.102539","DOIUrl":"10.1016/j.jglr.2025.102539","url":null,"abstract":"<div><div>The Laurentian Great Lakes have undergone significant ecological changes in recent decades. We characterized patterns and long-term trends in particulate nutrient concentrations and seston stoichiometry from 1997 to 2019 across all five Great Lakes using spring and summer particulate nutrient data routinely collected by the US EPA GLNPO Water Quality Monitoring Program. We observed broad differences between the upper and lower Great Lakes, likely driven by varying surrounding land use, nutrient dynamics, light and hydrological regimes, and internal processes. Lakes Huron and Michigan exhibited the most significant changes in particulate nutrient concentrations throughout the study period. Despite changes in particulate nutrient concentrations, no significant trends in seston stoichiometric ratios were observed in any of the lakes. We identified two periods of abrupt change (mid-2000s and 2012) in the particulate nutrient time series. The first period of change was characterized by significant declines in total suspended solids, particulate phosphorus, and particulate organic carbon concentrations, concurrent with the timing of documented lower food web changes in Lakes Huron and Michigan but preceding the period of rapid quagga mussel expansion into the Great Lakes. Since 2012, particulate nitrogen has abruptly increased in all lakes, resulting in increasingly imbalanced seston N:P and C:N. These shifts may have broader ecological implications, potentially affecting organisms higher up the food web through altered nutrient availability and balance. Tracking particulate nutrients will continue to be critical for lake management.</div></div>","PeriodicalId":54818,"journal":{"name":"Journal of Great Lakes Research","volume":"51 2","pages":"Article 102539"},"PeriodicalIF":2.4,"publicationDate":"2025-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143631887","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}

{"title":"Genetic characterization and interspecies gene flow among the Oreochromis species in the Lake Victoria and Kyoga basins, Uganda: Implications for conservation","authors":"Gerald Kwikiriza ,&nbsp;Papius Dias Tibihika ,&nbsp;Ivan Abaho ,&nbsp;Juliet Kigongo Nattabi ,&nbsp;Thapasya Vijayan ,&nbsp;Christina Rupprecht ,&nbsp;Manuel Curto ,&nbsp;Andreas Melcher ,&nbsp;Harald Meimberg","doi":"10.1016/j.jglr.2025.102535","DOIUrl":"10.1016/j.jglr.2025.102535","url":null,"abstract":"<div><div>Despite the significant fishery contribution of the Victoria and Kyoga basins, the ecosystems have continuously been threatened by overfishing and introduction of alien species, among others. These activities have contributed to a significant decline of the native tilapiines, the Singida tilapia (<em>Oreochromis esculentus</em>) and Victoria tilapia (<em>Oreochromis variabilis</em>)<em>.</em> As a consequence, the native species have been relegated to smaller satellite lakes and replaced by non-native species comprising Nile tilapia (<em>O</em>. <em>niloticus</em>) and blue spotted tilapia (<em>O. leucostictus</em>)<em>.</em> Therefore, to better understand the implications of these events, it is important to assess the status of both native and non-native species in the Victoria and Kyoga basins for sustainable science-based informed management options. Utilizing both microsatellite and mitochondrial (mt) DNA markers, we sequenced a total of 739 individuals from the Victoria and Kyoga basins comprising <em>O. niloticus</em> (333), <em>O. esculentus</em> (151)<em>,</em> and <em>O. leucostictus</em> (258). Generally, all the species and their respective populations exhibited lower genetic diversity as well as genetic differentiation. The principal coordinate analysis showed three main distinct groups corresponding to the three species studied highlighting their genetic differentiation. However, some evidence of introgressive hybridization observed between <em>O. niloticus</em> and <em>O. esculentus</em> as well as <em>O. esculentus</em> and <em>O. leucostictus</em> suggests a need for a tailored management strategy to preserve the genetic integrity of all three <em>Oreochromis</em> species while minimizing the hybridization risks. The study recommends that the satellite waterbodies containing pure stocks of <em>O. esculentus</em> should be conserved separately with higher priority.</div></div>","PeriodicalId":54818,"journal":{"name":"Journal of Great Lakes Research","volume":"51 2","pages":"Article 102535"},"PeriodicalIF":2.4,"publicationDate":"2025-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143631813","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The lampricide 3-trifluoromethyl-4-nitrophenol (TFM) stimulates oxygen consumption by larval sea lamprey in a dose-dependent manner","authors":"Leonard D’Souza ,&nbsp;Hugo Flávio ,&nbsp;Michael P. Wilkie","doi":"10.1016/j.jglr.2025.102536","DOIUrl":"10.1016/j.jglr.2025.102536","url":null,"abstract":"<div><div>Sea lamprey (<em>Petromyzon marinus</em>) are an invasive species in the Laurentian Great Lakes, where parasitism by blood-feeding juvenile lampreys greatly reduced populations of economically and culturally important native fishes in the early-mid 1900s. To control sea lamprey populations, the lampricide 3-trifluoromethyl-4-nitrophenol (TFM) is added to streams infested with larval sea lamprey. Sea lamprey have a lower capacity to detoxify TFM than most non-target fishes, making it a highly effective pesticide. TFM decreases ATP production by disrupting oxidative phosphorylation in the mitochondria, leading to an increase in mitochondrial oxygen consumption. However, little is known about how TFM affects whole animal oxygen consumption in sea lamprey and other fishes. To test the hypothesis that TFM has dose-dependent effects on larval sea lamprey metabolic rate, we measured the mass-specific oxygen consumption rates (<span><math><msub><mi>Ṁ</mi><msub><mi>O</mi><mn>2</mn></msub></msub></math></span>) of larval sea lamprey using intermittent-flow respirometry during TFM exposure. Exposure to increasing concentrations of TFM led to stepwise increases in <span><math><msub><mi>Ṁ</mi><msub><mi>O</mi><mn>2</mn></msub></msub></math></span> in larval sea lamprey, resulting in death after <span><math><msub><mi>Ṁ</mi><msub><mi>O</mi><mn>2</mn></msub></msub></math></span> reached levels equivalent to their known maximum metabolic rates. Similar measurements of <span><math><msub><mi>Ṁ</mi><msub><mi>O</mi><mn>2</mn></msub></msub></math></span> could be used to determine the relative TFM sensitivity of non-target species to better assess the potential impacts of TFM on resident fisheries.</div></div>","PeriodicalId":54818,"journal":{"name":"Journal of Great Lakes Research","volume":"51 2","pages":"Article 102536"},"PeriodicalIF":2.4,"publicationDate":"2025-02-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143631814","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Connecting tributary mercury loads to nearshore and offshore sediments in Lake Superior","authors":"Sarah E. Janssen ,&nbsp;Michael T. Tate ,&nbsp;Eric D. Dantoin ,&nbsp;Christopher T. Filstrup ,&nbsp;Euan D. Reavie ,&nbsp;Robert M. Stewart ,&nbsp;Chris Robinson ,&nbsp;Craig J. Allan ,&nbsp;Dale M. Robertson ,&nbsp;David P. Krabbenhoft","doi":"10.1016/j.jglr.2024.102381","DOIUrl":"10.1016/j.jglr.2024.102381","url":null,"abstract":"<div><div>Lake Superior has a vast and largely undeveloped watershed in comparison to the other Great Lakes, which makes it challenging to study mercury (Hg) sources and cycling. To examine Hg inputs to Lake Superior, we conducted an expansive binational assessment in 40 watersheds from a diverse range of landcover types. We further paired tributary Hg data to sediment source portfolios in the nearshore and offshore zones of Lake Superior through partnership with the Great Lakes Sediment Surveillance Program. We observed that total Hg loads were highest in the spring driven by the combination of elevated Hg concentrations and increased water discharge from snowmelt. In addition, total Hg concentrations in tributaries from remote, heavily forested regions, such as Pukaskwa National Park and the Minnesota Northshore, were higher than the Southshore and Thunder Bay regions. Methylmercury concentrations and loads were more spatially dependent, often corresponding to regions with more wetlands (e.g., Michigan Upper Peninsula). We estimated that the total Hg tributary load to Lake Superior in 2021 was 126 kg per year. To further examine the fate of watershed Hg sources, we examined sediments from 28 sites in Lake Superior using Hg stable isotopes. At open water sites, precipitation was the primary Hg source to sediments, but within nearshore sites Hg originated predominantly from watershed runoff. This work further defines the sources and fate of Hg within Lake Superior and highlights how Hg delivery is intrinsically tied to varying hydrologic regimes.</div></div>","PeriodicalId":54818,"journal":{"name":"Journal of Great Lakes Research","volume":"51 1","pages":"Article 102381"},"PeriodicalIF":2.4,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141692477","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A comparison of phytoplankton development in Lake Baikal, Siberia, and Rybinsk Reservoir, Volga River, European Russia, using stability indices","authors":"Natalya Mineeva ,&nbsp;Nina Bondarenko","doi":"10.1016/j.jglr.2024.102493","DOIUrl":"10.1016/j.jglr.2024.102493","url":null,"abstract":"<div><div>Based on observations of 2009–2022, the state of phytoplankton and its main taxa was analyzed in Lake Baikal (Siberia, Russia) and Rybinsk Reservoir (European Russia), two large freshwater lake reservoirs. Data were collected during periods of phytoplankton seasonal maxima which determine the total level of their annual production. The development of phytoplankton was assessed by biomass expressed in units of wet weight for Lake Baikal and units of chlorophyll <em>a</em> for the Rybinsk Reservoir. To assess the sustainability of biomass, its coefficients of variation, deviation from the mean value, and population stability index were calculated. These metrics did not reveal any definite inter-annual trends in the state of phytoplankton, but showed sharp changes in the level of community resistance in years with different trophic state. In both water bodies, a decrease in stability was observed under conditions atypical for the ecosystem. In the oligotrophic Lake Baikal, the most unstable situation was noted in highly productive years with the mass development of diatoms in the spring plankton. In the moderately eutrophic Rybinsk Reservoir, its resistance decreased in low productivity years with a weak summer development of phytoplankton and cyanobacteria due to the unfavorable weather conditions. The proposed approach will be of interest for assessing the stability of other aquatic ecosystems.</div></div>","PeriodicalId":54818,"journal":{"name":"Journal of Great Lakes Research","volume":"51 1","pages":"Article 102493"},"PeriodicalIF":2.4,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143129449","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}

{"title":"Role of tributary cyanobacterial and nutrient transport and sediment processes on cyanobacterial bloom initiation in Lake Superior nearshore","authors":"Rebecca M. Kreiling ,&nbsp;Carrie E. Givens ,&nbsp;Anna C. Baker ,&nbsp;Richard L. Kiesling ,&nbsp;Eric D. Dantoin ,&nbsp;Patrik M. Perner ,&nbsp;Shelby P. Sterner ,&nbsp;Kenna J. Gierke ,&nbsp;Paul C. Reneau","doi":"10.1016/j.jglr.2024.102409","DOIUrl":"10.1016/j.jglr.2024.102409","url":null,"abstract":"<div><div>Watershed fluxes of suspended sediment (SS), nutrients, in particular phosphorus (P), and cyanobacteria may play a role in driving cyanobacterial blooms along the southwestern shore of oligotrophic Lake Superior. To understand how tributary loads contribute to nearshore blooms, we sampled two southwestern shore tributaries, Bois Brule and Siskiwit Rivers. We collected water-quality samples to compute nutrient and sediment loads and to assess cyanobacteria community composition from the tributaries to the nearshore. We collected suspended and streambed sediment to assess the capacity for sediment to store and transport bioavailable P and to assess cyanobacteria community composition. Storm flows drove export of SS, total P, and total nitrogen, with the majority of total P being particulate P. Equilibrium P concentrations revealed that SS sorbed P as it is moved through the stream network across sites and seasons and was a potential source of P to the nearshore. However, streambed sediment in the Bois Brule and Siskiwit River watersheds were P sinks during summer, which potentially delayed transport of dissolved P to the lake. The cyanobacteria community varied spatially and temporally relating to multiple environmental variables including nutrients (P, N, and C) and specific conductivity. Cyanobacteria capable of producing cyanotoxins were present in tributaries and found across multiple environmental compartments indicating a potential for fluvial flow to the nearshore. This study demonstrated that streamflow is a primary driver of total nutrient and sediment loading in both watersheds, which indicates the potential for algal loading to the nearshore via suspended sediment or water.</div></div>","PeriodicalId":54818,"journal":{"name":"Journal of Great Lakes Research","volume":"51 1","pages":"Article 102409"},"PeriodicalIF":2.4,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143129561","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Synthetic microfibers are ubiquitous in benthic algae from the Laurentian Great Lakes","authors":"Eddie Kostelnik ,&nbsp;Julie R. Peller ,&nbsp;Dror L. Angel ,&nbsp;Muruleedhara N. Byappanahalli ,&nbsp;Bharath Ganesh Babu ,&nbsp;Mary Anne Evans","doi":"10.1016/j.jglr.2025.102527","DOIUrl":"10.1016/j.jglr.2025.102527","url":null,"abstract":"<div><div>Synthetic microfibers are a class of microplastics routinely released into environmental media from domestic laundry and wastewater treatment plant effluent. Areas of high human population density discharge immense amounts of synthetic microfibers that pollute and accumulate in sediments, surface waters, algae, and other parts of the ecosystem. Synthetic microfibers are abundant in the Laurentian Great Lakes of North America, but their movement and fate are not well understood. Macroalgae effectively sequester microfibers; however, it is unknown if quantities of synthetic microfibers differ in benthic algae of the Great Lakes based on human population density or algal type (such as Cladophora or charophytes). Presented here is a 4-year study that investigated benthic algae samples from four of the Laurentian Great Lakes: Lakes Michigan, Huron, Ontario, and Erie. Synthetic microfibers were isolated and quantified in the algal samples, and values were analyzed with respect to algal type, lake, and population density. The average estimated number of synthetic microfibers per kg (dry weight) of benthic algae in each lake ranged from 1.6 <span><math><mrow><mo>×</mo></mrow></math></span> 10⁴ to 2.0 <span><math><mrow><mo>×</mo></mrow></math></span> 10⁴. Microscopic analysis suggested a possible interaction between epiphytic diatoms and benthic macroalgae (<em>Cladophora</em>), which may help to explain the ability of the algae to sequester microfibers regardless of algal type. The results also suggest a lack of correlation between human population density and number of synthetic microfibers in benthic algae, which could imply facile movement and distribution of microfibers in large bodies of water, that includes the aquatic food web of macroinvertebrates and fish communities.</div></div>","PeriodicalId":54818,"journal":{"name":"Journal of Great Lakes Research","volume":"51 2","pages":"Article 102527"},"PeriodicalIF":2.4,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143631890","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}

{"title":"Food web structure of the Lake Superior fish community in 2021–2022","authors":"Ariel N. Edwards ,&nbsp;Shawn P. Sitar ,&nbsp;Ashley H. Moerke ,&nbsp;Jonathan P. Doubek ,&nbsp;Daniel L. Yule ,&nbsp;Dray D. Carl ,&nbsp;Cory A. Goldsworthy ,&nbsp;Ian C. Harding ,&nbsp;S. Ben Michaels ,&nbsp;Eric K. Berglund ,&nbsp;Seth A. Moore ,&nbsp;Brandon S. Gerig","doi":"10.1016/j.jglr.2024.102486","DOIUrl":"10.1016/j.jglr.2024.102486","url":null,"abstract":"<div><div>The trophic linkages and ecological requirements of the Lake Superior fish community have not been assessed on a whole lake scale in over a decade. Here, we investigated the trophic dynamics across multiple species and habitat zones of Lake Superior. From April to October of 2021 and 2022, a total of five piscivore, four planktivore, and six benthivore species were collected by region and length class during bottom-trawl, standard gillnet, commercial cisco gillnet, and recreational angler surveys. To assess trophic linkages, stomach contents were measured to estimate biomass consumed and a multivariate analysis was used to assess diet composition by species, length, and region. We found a high degree of interconnectedness in the Lake Superior food web, with <em>Mysis</em> as a critical diet item for most fishes. Native piscivore diets varied by region and with ontogeny. Lake charr were important habitat couplers in the lake, exhibiting a diverse diet and opportunistic foraging strategy. Conversely, Pacific salmon were more restricted in their foraging. Planktivores and benthivores primarily consumed <em>Mysis</em>, with less reliance on <em>Diporeia</em> compared to previous studies. Lake whitefish and cisco were the exception to this pattern, with broader bathymetric depth distributions represented in their diets. We found the food web to be supported by a predominantly native species assemblage, with redundancies at all trophic levels.</div></div>","PeriodicalId":54818,"journal":{"name":"Journal of Great Lakes Research","volume":"51 1","pages":"Article 102486"},"PeriodicalIF":2.4,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143129595","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}

{"title":"Stable isotope analysis of western Lake Superior predatory fishes, part one: Trophic niche overlap","authors":"Jessica Hanson ,&nbsp;Morgann Gordon ,&nbsp;Nick Peterson ,&nbsp;Ryan Lepak ,&nbsp;Cory Goldsworthy ,&nbsp;Valerie Brady ,&nbsp;Thomas Hrabik ,&nbsp;Joel Hoffman","doi":"10.1016/j.jglr.2024.102441","DOIUrl":"10.1016/j.jglr.2024.102441","url":null,"abstract":"<div><div>Characterizing food web interactions between introduced and native fish predators is important to quantify niche overlap, assess predator–prey balance, and support fisheries management. Lake Superior provides an ideal setting to investigate potential trophic overlap between native top predators, lake trout (<em>Salvelinus namaycush</em>) and walleye (<em>Sander vitreus</em>), and a diverse assemblage of introduced salmonids. Angler-caught fish were used to measure trophic position and niche overlap between predatory fishes in the western arm of Lake Superior based on carbon and nitrogen stable isotope ratios (δ¹³C, δ¹⁵N). Within a species, we did not find consistent differences in either δ¹³C or δ¹⁵N values by sex, collection year, capture location, or length. Among species, the range in δ¹⁵N values was &gt;5 ‰, indicating that these species occupy ∼2 trophic positions, with dietary reliance ranging from primarily invertebrates to primarily fish, whereas the range in δ¹³C values indicated dietary reliance on a mix of pelagic and benthic prey. Combined, the δ¹³C and δ¹⁵N values revealed siscowet lake trout as the apex predator having a distinct trophic niche, while walleye and lean lake trout were intermediate trophic position predators with overlapping isotopic niches, and introduced salmonids were the lowest trophic position predators with overlapping trophic niches. Overlapping trophic niches indicated similar resource reliance and habitat occupancy among native lake trout and walleye, as well as among introduced salmonids, but less so between native and introduced predators.</div></div>","PeriodicalId":54818,"journal":{"name":"Journal of Great Lakes Research","volume":"51 1","pages":"Article 102441"},"PeriodicalIF":2.4,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143129597","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}