Pub Date : 2024-08-27DOI: 10.1016/j.jglr.2024.102417
Stephanie E. Figary , James M. Watkins , T. Bruce Lauber , Anne E. Scofield , Lars G. Rudstam
Zooplankton are a vital component of the food web as the major conduit of energy from primary producers to planktivorous fishes. Therefore, changes in the structure of the zooplankton community affect how energy moves through aquatic ecosystems. Changes in the zooplankton community structure are typically documented through detailed community analysis, which can be difficult to interpret and communicate to non-experts. Alternatively, a few key summary indicators of community structure may better disseminate this information to a broader audience. In this study we analyzed zooplankton data from 1997 to 2019 from the US Environmental Protection Agency’s Great Lakes National Program Office to select indicators that summarized changes in the zooplankton community. Two indicators (percent of calanoids by biomass and areal density of herbivorous cladocerans) detected known changes in lakes Huron, Michigan, and Ontario, correlated with the crustacean zooplankton areal biomass above (herbivorous cladocerans) or in the hypolimnion (percent calanoids), and were related to the lake or basin-wide Carlson’s Trophic State Index based on chlorophyll (TSIchl) (percent calanoids by biomass). Our findings suggest that employing one or both selected indicators in addition to TSIchl and total crustacean zooplankton areal biomass, an already reported indicator in the Great Lakes that captures overall food availability for fish, would provide additional key information about zooplankton community structure in simple metrics that could be effectively communicated to stakeholders.
{"title":"Revisiting zooplankton as indicators in the Great Lakes: Which indicators detect temporal changes in the zooplankton community composition?","authors":"Stephanie E. Figary , James M. Watkins , T. Bruce Lauber , Anne E. Scofield , Lars G. Rudstam","doi":"10.1016/j.jglr.2024.102417","DOIUrl":"10.1016/j.jglr.2024.102417","url":null,"abstract":"<div><div>Zooplankton are a vital component of the food web as the major conduit of energy from primary producers to planktivorous fishes. Therefore, changes in the structure of the zooplankton community affect how energy moves through aquatic ecosystems. Changes in the zooplankton community structure are typically documented through detailed community analysis, which can be difficult to interpret and communicate to non-experts. Alternatively, a few key summary indicators of community structure may better disseminate this information to a broader audience. In this study we analyzed zooplankton data from 1997 to 2019 from the US Environmental Protection Agency’s Great Lakes National Program Office to select indicators that summarized changes in the zooplankton community. Two indicators (percent of calanoids by biomass and areal density of herbivorous cladocerans) detected known changes in lakes Huron, Michigan, and Ontario, correlated with the crustacean zooplankton areal biomass above (herbivorous cladocerans) or in the hypolimnion (percent calanoids), and were related to the lake or basin-wide Carlson’s Trophic State Index based on chlorophyll (TSI<sub>chl</sub>) (percent calanoids by biomass). Our findings suggest that employing one or both selected indicators in addition to TSI<sub>chl</sub> and total crustacean zooplankton areal biomass, an already reported indicator in the Great Lakes that captures overall food availability for fish, would provide additional key information about zooplankton community structure in simple metrics that could be effectively communicated to stakeholders.</div></div>","PeriodicalId":54818,"journal":{"name":"Journal of Great Lakes Research","volume":"50 5","pages":"Article 102417"},"PeriodicalIF":2.4,"publicationDate":"2024-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142316240","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 : 2024-08-26DOI: 10.1016/j.jglr.2024.102425
Kirill Shchapov, E. Todd Howell, Tara George, Sapna Sharma
Cyanobacterial blooms, often associated with warm, eutrophic lakes, are of widespread concern owing to their potential disruption of ecological and public health. Recently, cyanobacterial blooms have been observed in oligotrophic lakes, including Lake Superior, a large cold-water system. Despite recent developments, limited research has targeted phytoplankton assemblages in the northern Lake Superior nearshore, where isolated cyanobacteria blooms have emerged since 2019. In 2019, the cyanobacteria assemblage at 10 nearshore monitoring stations was examined to understand potential bloom-forming taxa and their association with water quality. We observed a diverse cyanobacteria assemblage, with highest densities in spring and biomass in fall. , and sp. were the most prevalent species across sites and seasons. Variation partitioning analysis revealed that water quality conditions were more influential drivers of cyanobacteria density and biomass than meteorological factors, particularly in regions with elevated nutrient inputs and following stormy conditions. However, at present, cyanobacteria compose <15 % of the total phytoplankton biomass in the study areas. Our monitoring data and recent reports of cyanobacteria blooms on the north shore, suggests that current blooms are not widespread. Nonetheless, we found a diverse array of cyanobacteria taxa, with most capable of producing cyanotoxins. Considering the global uncertainty in the factors contributing to cyanobacteria blooms, in association with the large-scale climatic changes affecting Lake Superior, a proactive approach to assessing risks of blooms is suggested. This should include data-generating efforts (e.g., frequent phytoplankton monitoring and reported blooms investigations) to support future collaborative initiatives focused on managing cyanobacterial blooms.
{"title":"Cyanobacteria in cold waters: A study of nearshore cyanobacteria assemblages in Lake Superior","authors":"Kirill Shchapov, E. Todd Howell, Tara George, Sapna Sharma","doi":"10.1016/j.jglr.2024.102425","DOIUrl":"https://doi.org/10.1016/j.jglr.2024.102425","url":null,"abstract":"Cyanobacterial blooms, often associated with warm, eutrophic lakes, are of widespread concern owing to their potential disruption of ecological and public health. Recently, cyanobacterial blooms have been observed in oligotrophic lakes, including Lake Superior, a large cold-water system. Despite recent developments, limited research has targeted phytoplankton assemblages in the northern Lake Superior nearshore, where isolated cyanobacteria blooms have emerged since 2019. In 2019, the cyanobacteria assemblage at 10 nearshore monitoring stations was examined to understand potential bloom-forming taxa and their association with water quality. We observed a diverse cyanobacteria assemblage, with highest densities in spring and biomass in fall. , and sp. were the most prevalent species across sites and seasons. Variation partitioning analysis revealed that water quality conditions were more influential drivers of cyanobacteria density and biomass than meteorological factors, particularly in regions with elevated nutrient inputs and following stormy conditions. However, at present, cyanobacteria compose <15 % of the total phytoplankton biomass in the study areas. Our monitoring data and recent reports of cyanobacteria blooms on the north shore, suggests that current blooms are not widespread. Nonetheless, we found a diverse array of cyanobacteria taxa, with most capable of producing cyanotoxins. Considering the global uncertainty in the factors contributing to cyanobacteria blooms, in association with the large-scale climatic changes affecting Lake Superior, a proactive approach to assessing risks of blooms is suggested. This should include data-generating efforts (e.g., frequent phytoplankton monitoring and reported blooms investigations) to support future collaborative initiatives focused on managing cyanobacterial blooms.","PeriodicalId":54818,"journal":{"name":"Journal of Great Lakes Research","volume":"4 1","pages":""},"PeriodicalIF":2.2,"publicationDate":"2024-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142249744","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 : 2024-08-26DOI: 10.1016/j.jglr.2024.102424
Jeremiah S. Shrovnal, Bradley A. Ray, Dray D. Carl, Stephanie L. Shaw, Scott A. Sapper, Christopher A. Zunker, Ross A. Lind
Cisco () support an evolving commercial roe fishery in Wisconsin waters of Lake Superior. To monitor trends in spawning cisco abundance, fishery managers recently began estimating adult biomass and exploitation using fall hydroacoustic surveys, which were combined with gill net surveys to inform apportionments of acoustic data. The gill net survey design consisted of paired top-suspended and bottom-set gill nets, but only the sex ratios from top nets are currently used with the hydroacoustic surveys due to an assumption that cisco in Lake Superior are pelagic spawners. However, the vertical sex distribution of cisco during spawning aggregations has been described as dynamic, with males becoming more bottom-oriented throughout the spawning season. We used multilevel aggregated binomial regressions to: 1) determine if there is bias between top and bottom gill net catches of cisco for either sex and if it changes throughout the spawning season, 2) evaluate how the vertical distribution of males and females may create bias in sex ratios used to estimate exploitation, and 3) explore the effect that maturity (i.e., gonadal development) has on vertical distribution during spawning aggregations. We identified sex-specific bias in vertical catch location that has the potential to bias estimates of sex ratio, and the source of this bias may be attributable to maturity driven changes in behavior. These findings highlight a need for caution when relying on gill nets to apportion cisco sex ratios during spawning aggregations and provide support for a non-pelagic alternative hypothesis of spawning behavior.
{"title":"Vertical distribution of Lake Superior cisco (Coregonus artedi) spawning aggregations and implications for population monitoring","authors":"Jeremiah S. Shrovnal, Bradley A. Ray, Dray D. Carl, Stephanie L. Shaw, Scott A. Sapper, Christopher A. Zunker, Ross A. Lind","doi":"10.1016/j.jglr.2024.102424","DOIUrl":"https://doi.org/10.1016/j.jglr.2024.102424","url":null,"abstract":"Cisco () support an evolving commercial roe fishery in Wisconsin waters of Lake Superior. To monitor trends in spawning cisco abundance, fishery managers recently began estimating adult biomass and exploitation using fall hydroacoustic surveys, which were combined with gill net surveys to inform apportionments of acoustic data. The gill net survey design consisted of paired top-suspended and bottom-set gill nets, but only the sex ratios from top nets are currently used with the hydroacoustic surveys due to an assumption that cisco in Lake Superior are pelagic spawners. However, the vertical sex distribution of cisco during spawning aggregations has been described as dynamic, with males becoming more bottom-oriented throughout the spawning season. We used multilevel aggregated binomial regressions to: 1) determine if there is bias between top and bottom gill net catches of cisco for either sex and if it changes throughout the spawning season, 2) evaluate how the vertical distribution of males and females may create bias in sex ratios used to estimate exploitation, and 3) explore the effect that maturity (i.e., gonadal development) has on vertical distribution during spawning aggregations. We identified sex-specific bias in vertical catch location that has the potential to bias estimates of sex ratio, and the source of this bias may be attributable to maturity driven changes in behavior. These findings highlight a need for caution when relying on gill nets to apportion cisco sex ratios during spawning aggregations and provide support for a non-pelagic alternative hypothesis of spawning behavior.","PeriodicalId":54818,"journal":{"name":"Journal of Great Lakes Research","volume":"36 1","pages":""},"PeriodicalIF":2.2,"publicationDate":"2024-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142187431","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 : 2024-08-22DOI: 10.1016/j.jglr.2024.102415
Martin A. Simonson , David B. Bunnell , Charles P. Madenjian , Kevin M. Keeler , Joseph D. Schmitt
The cisco Coregonus artedi is a coldwater fish that is distributed throughout much of Canada and the northern United States, including the Laurentian Great Lakes. Cisco historically supported large commercial fisheries in the Great Lakes during the late 1800s and early 1900s, but many populations declined and never recovered. Restoration efforts focusing on re-establishing cisco in the Great Lakes are underway, but increasing water temperatures may hinder these efforts. Therefore, we examined aerobic scope and thermal tolerance of allopatric cisco populations from different latitudes and habitats to determine if a southern latitude population (Crooked Lake, Indiana, USA) near the southern edge of cisco distribution was better adapted to withstand warmer water temperatures than a northern latitude population (Les Cheneaux Islands, Michigan, USA; Lake Huron). As expected, both stocks demonstrated increases in metabolic rates and absolute aerobic scope with increased temperature. Northern cisco had significantly lower aerobic scope compared to southern cisco at both treatment temperatures of 10 and 13 °C. Both cisco stocks had high thermal tolerances when challenged by temperatures increased to 20 and 23 °C but low tolerances at 26 °C. Cisco thermal tolerances increased with acclimation temperature, but we did not detect a difference in thermal tolerances between northern and southern cisco. Although southern cisco had higher capacity for aerobic metabolism, both stock sources had high thermal tolerances at the upper end of their thermal limits. Therefore, either population would be likely suitable for reintroduction into Great Lakes habitats, even with expected warming in the future.
{"title":"Comparison of cisco (Coregonus artedi) aerobic scope and thermal tolerance between two latitudinally-separated populations","authors":"Martin A. Simonson , David B. Bunnell , Charles P. Madenjian , Kevin M. Keeler , Joseph D. Schmitt","doi":"10.1016/j.jglr.2024.102415","DOIUrl":"10.1016/j.jglr.2024.102415","url":null,"abstract":"<div><div>The cisco <em>Coregonus artedi</em> is a coldwater fish that is distributed throughout much of Canada and the northern United States, including the Laurentian Great Lakes. Cisco historically supported large commercial fisheries in the Great Lakes during the late 1800s and early 1900s, but many populations declined and never recovered. Restoration efforts focusing on re-establishing cisco in the Great Lakes are underway, but increasing water temperatures may hinder these efforts. Therefore, we examined aerobic scope and thermal tolerance of allopatric cisco populations from different latitudes and habitats to determine if a southern latitude population (Crooked Lake, Indiana, USA) near the southern edge of cisco distribution was better adapted to withstand warmer water temperatures than a northern latitude population (Les Cheneaux Islands, Michigan, USA; Lake Huron). As expected, both stocks demonstrated increases in metabolic rates and absolute aerobic scope with increased temperature. Northern cisco had significantly lower aerobic scope compared to southern cisco at both treatment temperatures of 10 and 13 °C. Both cisco stocks had high thermal tolerances when challenged by temperatures increased to 20 and 23 °C but low tolerances at 26 °C. Cisco thermal tolerances increased with acclimation temperature, but we did not detect a difference in thermal tolerances between northern and southern cisco. Although southern cisco had higher capacity for aerobic metabolism, both stock sources had high thermal tolerances at the upper end of their thermal limits. Therefore, either population would be likely suitable for reintroduction into Great Lakes habitats, even with expected warming in the future.</div></div>","PeriodicalId":54818,"journal":{"name":"Journal of Great Lakes Research","volume":"50 5","pages":"Article 102415"},"PeriodicalIF":2.4,"publicationDate":"2024-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142316133","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 : 2024-08-22DOI: 10.1016/j.jglr.2024.102411
Dominique S. Gilbert , Brett A. Hayhurst , Sarah Grubisich , Nick Schneider , Olivia Martin , Christopher DeNyse , Kristina M. Chomiak , Anna Christina Tyler , Nathan C. Eddingsaas
This study is intended as a bellwether for the occurrence of microplastics (MPs) in Great Lakes wetlands. In 2020, sediment, surface water, and atmospheric deposition samples were collected from wetland catchments in or near five National Wildlife Refuges (NWRs) in the Great Lakes region: Horicon-WI, Seney-MI, Shiawassee-MI, Ottawa-OH, and Montezuma-NY. Sediment and surface water samples were taken from river, stream, and canal inflows and outflows to and from wetland areas. Atmospheric deposition samples were collected in carboys placed near established rain gauges. These sample sites were chosen as indicators of MP deposition into and out of the region’s wetland systems. MPs (100 μm–4 mm surface water samples; 63 μm–4 mm sediment and atmospheric deposition samples) were extracted from each sample, enumerated, and categorized by particle morphology and polymer type. Average MP particle abundances in the sediment and surface water samples ranged from 344 to 538 particles kg−1 (dry weight) and 2–68 particles m−3, respectively. Atmospheric MP deposition ranged from 5.8 to 22.6 particles m−2 d−1. Fibers were the most abundant MP particle type found in each sample type (sediment, surface water, and atmospheric deposition), followed by fragments. These results suggest that input and retention of MPs are pervasive in the Great Lakes region and surrounding wetland areas.
{"title":"A bellwether for microplastic in wetland catchments in the Great Lakes region","authors":"Dominique S. Gilbert , Brett A. Hayhurst , Sarah Grubisich , Nick Schneider , Olivia Martin , Christopher DeNyse , Kristina M. Chomiak , Anna Christina Tyler , Nathan C. Eddingsaas","doi":"10.1016/j.jglr.2024.102411","DOIUrl":"10.1016/j.jglr.2024.102411","url":null,"abstract":"<div><div>This study is intended as a bellwether for the occurrence of microplastics (MPs) in Great Lakes wetlands. In 2020, sediment, surface water, and atmospheric deposition samples were collected from wetland catchments in or near five National Wildlife Refuges (NWRs) in the Great Lakes region: Horicon-WI, Seney-MI, Shiawassee-MI, Ottawa-OH, and Montezuma-NY. Sediment and surface water samples were taken from river, stream, and canal inflows and outflows to and from wetland areas. Atmospheric deposition samples were collected in carboys placed near established rain gauges. These sample sites were chosen as indicators of MP deposition into and out of the region’s wetland systems. MPs (100 μm–4 mm surface water samples; 63 μm–4 mm sediment and atmospheric deposition samples) were extracted from each sample, enumerated, and categorized by particle morphology and polymer type. Average MP particle abundances in the sediment and surface water samples ranged from 344 to 538 particles kg<sup>−1</sup> (dry weight) and 2–68 particles m<sup>−3</sup>, respectively. Atmospheric MP deposition ranged from 5.8 to 22.6 particles m<sup>−2</sup> d<sup>−1</sup>. Fibers were the most abundant MP particle type found in each sample type (sediment, surface water, and atmospheric deposition), followed by fragments. These results suggest that input and retention of MPs are pervasive in the Great Lakes region and surrounding wetland areas.</div></div>","PeriodicalId":54818,"journal":{"name":"Journal of Great Lakes Research","volume":"50 5","pages":"Article 102411"},"PeriodicalIF":2.4,"publicationDate":"2024-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142316237","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 : 2024-08-22DOI: 10.1016/j.jglr.2024.102416
Owen M. Stefaniak , Faith A. Fitzpatrick , Brennan A. Dow , James D. Blount , Daniel J. Sullivan , Paul C. Reneau
To better understand the primary drivers of the thermal regime in a Great Lakes estuary, and their implications for local biota, water temperature variations in the Milwaukee Estuary of Lake Michigan were studied between July and October of 2019 using a network of 25 sensors at 18 locations. Like Lake Michigan, the estuary was thermally stratified July to October, and historically dredged channels with water depths greater than 6 m allowed for the free movement of cold lake water into the estuary. However, temperatures in the estuary fluctuated rapidly both spatially and temporally, reflecting lake temperature fluctuations driven by changing meteorological conditions. Lake-driven upwelling and downwelling events influenced water temperature more than tributary contributions. Periodic upwelling and downwelling events caused temperature changes by up to 15 °C in less than 24 h. Nearshore upwelling events occasionally allowed cold, hypolimnetic lake water to reach tributary portions of the estuary beyond dredged areas, while downwelling events disrupted thermal stratification and caused the deep, dredged portions of the estuary to exceed 20 °C. Thermal impacts from these events were especially noticeable in transition zones between dredged and not dredged channels less than 2 m deep. The warming effects from downwelling persisted longer inside the estuary – up to two weeks – than cooling effects from upwelling, which typically lasted a few days. The predominantly lake-driven, rapid summer water temperature fluctuations observed in the Milwaukee Estuary serve as an important consideration in habitat restoration activities happening in Great Lakes estuaries.
{"title":"Influences of meteorological conditions, runoff, and bathymetry on summer thermal regime of a Great Lakes estuary","authors":"Owen M. Stefaniak , Faith A. Fitzpatrick , Brennan A. Dow , James D. Blount , Daniel J. Sullivan , Paul C. Reneau","doi":"10.1016/j.jglr.2024.102416","DOIUrl":"10.1016/j.jglr.2024.102416","url":null,"abstract":"<div><div>To better understand the primary drivers of the thermal regime in a Great Lakes estuary, and their implications for local biota, water temperature variations in the Milwaukee Estuary of Lake Michigan were studied between July and October of 2019 using a network of 25 sensors at 18 locations. Like Lake Michigan, the estuary was thermally stratified July to October, and historically dredged channels with water depths greater than 6 m allowed for the free movement of cold lake water into the estuary. However, temperatures in the estuary fluctuated rapidly both spatially and temporally, reflecting lake temperature fluctuations driven by changing meteorological conditions. Lake-driven upwelling and downwelling events influenced water temperature more than tributary contributions. Periodic upwelling and downwelling events caused temperature changes by up to 15 °C in less than 24 h. Nearshore upwelling events occasionally allowed cold, hypolimnetic lake water to reach tributary portions of the estuary beyond dredged areas, while downwelling events disrupted thermal stratification and caused the deep, dredged portions of the estuary to exceed 20 °C. Thermal impacts from these events were especially noticeable in transition zones between dredged and not dredged channels less than 2 m deep. The warming effects from downwelling persisted longer inside the estuary – up to two weeks – than cooling effects from upwelling, which typically lasted a few days. The predominantly lake-driven, rapid summer water temperature fluctuations observed in the Milwaukee Estuary serve as an important consideration in habitat restoration activities happening in Great Lakes estuaries.</div></div>","PeriodicalId":54818,"journal":{"name":"Journal of Great Lakes Research","volume":"50 5","pages":"Article 102416"},"PeriodicalIF":2.4,"publicationDate":"2024-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0380133024001758/pdfft?md5=555a5d9dc1be2d20211fa046cec9b08c&pid=1-s2.0-S0380133024001758-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142316238","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}
Pub Date : 2024-08-22DOI: 10.1016/j.jglr.2024.102414
Cory A. Goldsworthy, Dray D. Carl, Shawn P. Sitar, Michael J. Seider, Mark R. Vinson, Ian Harding, Thomas C. Pratt, Paul P. Piszczek, Eric K. Berglund, Samuel B. Michaels, Jessica M. Barber
Lake Superior is the least anthropogenically impacted of the Laurentian Great Lakes ecosystems, yet dramatic changes to the fish community are evident. Previous published works chronicled those changes and the efforts to rehabilitate the fish community through the year 2000. Here, we review through the year 2022, where post-rehabilitation stability was driven by lean lake trout ( as the most abundant piscivore in nearshore waters, siscowet lake trout ( as the most abundant piscivore in offshore waters, and a healthy, intact assemblage of native prey species, which created ecological redundancies and helped stabilize the food web. Stocking of non-native salmonines was reduced 74%, and populations of Chinook salmon ( and coho salmon ( were maintained through natural reproduction. Despite reduced stocking, yield from recreational fisheries was stable. Likewise, developments in population modeling led to evaluations and refinement of management strategies that helped create stability for lake trout, lake whitefish (), and cisco () fisheries. With lake trout rehabilitation achieved, focus shifted toward rehabilitation of native brook trout (), lake sturgeon (), and walleye (). Despite continued control efforts, sea lamprey () abundance increased considerably, and estimates of fish killed by lampreys averaged 2.65 million kg annually. Environmental changes have benefited sea lampreys and fostered thermal habitats more suitable to non-native organisms, posing new challenges for managers and researchers. Nevertheless, the post-rehabilitation stability in the contemporary fish community will help provide resilience to future perturbations in the ecosystem.
{"title":"Lake Superior fish community and fisheries, 2001–2022: An era of stability","authors":"Cory A. Goldsworthy, Dray D. Carl, Shawn P. Sitar, Michael J. Seider, Mark R. Vinson, Ian Harding, Thomas C. Pratt, Paul P. Piszczek, Eric K. Berglund, Samuel B. Michaels, Jessica M. Barber","doi":"10.1016/j.jglr.2024.102414","DOIUrl":"https://doi.org/10.1016/j.jglr.2024.102414","url":null,"abstract":"Lake Superior is the least anthropogenically impacted of the Laurentian Great Lakes ecosystems, yet dramatic changes to the fish community are evident. Previous published works chronicled those changes and the efforts to rehabilitate the fish community through the year 2000. Here, we review through the year 2022, where post-rehabilitation stability was driven by lean lake trout ( as the most abundant piscivore in nearshore waters, siscowet lake trout ( as the most abundant piscivore in offshore waters, and a healthy, intact assemblage of native prey species, which created ecological redundancies and helped stabilize the food web. Stocking of non-native salmonines was reduced 74%, and populations of Chinook salmon ( and coho salmon ( were maintained through natural reproduction. Despite reduced stocking, yield from recreational fisheries was stable. Likewise, developments in population modeling led to evaluations and refinement of management strategies that helped create stability for lake trout, lake whitefish (), and cisco () fisheries. With lake trout rehabilitation achieved, focus shifted toward rehabilitation of native brook trout (), lake sturgeon (), and walleye (). Despite continued control efforts, sea lamprey () abundance increased considerably, and estimates of fish killed by lampreys averaged 2.65 million kg annually. Environmental changes have benefited sea lampreys and fostered thermal habitats more suitable to non-native organisms, posing new challenges for managers and researchers. Nevertheless, the post-rehabilitation stability in the contemporary fish community will help provide resilience to future perturbations in the ecosystem.","PeriodicalId":54818,"journal":{"name":"Journal of Great Lakes Research","volume":"6 1","pages":""},"PeriodicalIF":2.2,"publicationDate":"2024-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142187336","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 : 2024-08-07DOI: 10.1016/j.jglr.2024.102412
Christopher R. Mattheus, Mitchell E. Barklage
This paper reports on a high-resolution, regional sand assessment of the Chicago littoral zone, undertaken within ∼ 3 km from shore, to facilitate an improved process-based understanding of pocket-beach morphodynamics between the distinctive North and South sides of the Chicago Lake Michigan shoreline. While past studies have touched upon regional themes of sand limitation and littoral fragmentation by lakefill peninsulas and engineered shoreline infrastructure at these two areas, the integration of digital ‘chirper’ marine seismic reflection data (collected in 2022), geologic information from newly acquired sediment cores and lake-bottom grab samples (from 2023), and a 2020 LiDAR-based topobathymetric DEM provided the basis for geological lake-bottom unit characterization and delineation, a context for morphodynamics. Major findings are that: (1) The sandy lake bottom is distinct in bathymetric character from other compositions/textures, including bedrock, gravel-lag, and muddy sediments; (2) the Chicago North Side is sandier than the Chicago South Side; (3) sand thickness is greatest beneath urban pocket beaches and decreases sharply at the transition from engineered embayment to open lake environment; (4) sand thickness beyond semi-confinement is generally < 1 m, with the toe of the littoral sand wedge generally in > 5 m water depth; and (5) while the Chicago North Side littoral zone is continuously sandy alongshore, with few obstructions impacting unit continuity, that of the South Side is characterized by littoral fragmentation given exposure of bedrock highs. Differences in framework geology between Chicago North and South Sides are further enhanced by engineered shoreline structures and therewith associated littoral fragmentation.
{"title":"Lake-bottom geology of the Chicago nearshore: A sand-distribution context for urban beach morphodynamics along a fragmented littoral zone","authors":"Christopher R. Mattheus, Mitchell E. Barklage","doi":"10.1016/j.jglr.2024.102412","DOIUrl":"https://doi.org/10.1016/j.jglr.2024.102412","url":null,"abstract":"This paper reports on a high-resolution, regional sand assessment of the Chicago littoral zone, undertaken within ∼ 3 km from shore, to facilitate an improved process-based understanding of pocket-beach morphodynamics between the distinctive North and South sides of the Chicago Lake Michigan shoreline. While past studies have touched upon regional themes of sand limitation and littoral fragmentation by lakefill peninsulas and engineered shoreline infrastructure at these two areas, the integration of digital ‘chirper’ marine seismic reflection data (collected in 2022), geologic information from newly acquired sediment cores and lake-bottom grab samples (from 2023), and a 2020 LiDAR-based topobathymetric DEM provided the basis for geological lake-bottom unit characterization and delineation, a context for morphodynamics. Major findings are that: (1) The sandy lake bottom is distinct in bathymetric character from other compositions/textures, including bedrock, gravel-lag, and muddy sediments; (2) the Chicago North Side is sandier than the Chicago South Side; (3) sand thickness is greatest beneath urban pocket beaches and decreases sharply at the transition from engineered embayment to open lake environment; (4) sand thickness beyond semi-confinement is generally < 1 m, with the toe of the littoral sand wedge generally in > 5 m water depth; and (5) while the Chicago North Side littoral zone is continuously sandy alongshore, with few obstructions impacting unit continuity, that of the South Side is characterized by littoral fragmentation given exposure of bedrock highs. Differences in framework geology between Chicago North and South Sides are further enhanced by engineered shoreline structures and therewith associated littoral fragmentation.","PeriodicalId":54818,"journal":{"name":"Journal of Great Lakes Research","volume":"8 1","pages":""},"PeriodicalIF":2.2,"publicationDate":"2024-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142187335","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 : 2024-08-06DOI: 10.1016/j.jglr.2024.102410
Christopher Mulanda Aura , Ruth Lewo Mwarabu , Chrisphine Sangara Nyamweya , Collins Onyango Ongore , Safina Musa , James Last Keyombe , Fredrick Guya , Jane Fonda Awuor , Monica Owili , James Muriithi Njiru
Cage aquaculture is rapidly expanding in the African Great Lakes Region, with the potential of boosting fish output while also providing food security, poverty reduction, and job creation. However, there is growing concern that the proliferation of fish cages in Lake Victoria will have a detrimental effect on the lake’s ecology. Using Lake Victoria, Kenya as a case study, the current study evaluated the sustainability features of a community-based cage aquaculture that are based on socio-economic, physico-chemical, biological variables and risks in the lake and proposed potential mitigation measures. The potential production carrying capacity was estimated to be more than 500% of current cage culture production, but subject to the use of good aquaculture practices (GAPs) and best management practices (BMPs) for sustainable lake ecology. The study suggests using a community-based cage culture framework, appropriate policies and regulations, to improve lake and resource management, as well as to guide cage culture businesses, improve security, and facilitate resource usage dispute resolution procedures.
{"title":"Unbundling sustainable community-based cage aquaculture in an afrotropical lake for blue growth","authors":"Christopher Mulanda Aura , Ruth Lewo Mwarabu , Chrisphine Sangara Nyamweya , Collins Onyango Ongore , Safina Musa , James Last Keyombe , Fredrick Guya , Jane Fonda Awuor , Monica Owili , James Muriithi Njiru","doi":"10.1016/j.jglr.2024.102410","DOIUrl":"10.1016/j.jglr.2024.102410","url":null,"abstract":"<div><div>Cage aquaculture is rapidly expanding in the African Great Lakes Region, with the potential of boosting fish output while also providing food security, poverty reduction, and job creation. However, there is growing concern that the proliferation of fish cages in Lake Victoria will have a detrimental effect on the lake’s ecology. Using Lake Victoria, Kenya as a case study, the current study evaluated the sustainability features of a community-based cage aquaculture that are based on socio-economic, physico-chemical, biological variables and risks in the lake and proposed potential mitigation measures. The potential production carrying capacity was estimated to be more than 500% of current cage culture production, but subject to the use of good aquaculture practices (GAPs) and best management practices (BMPs) for sustainable lake ecology. The study suggests using a community-based cage culture framework, appropriate policies and regulations, to improve lake and resource management, as well as to guide cage culture businesses, improve security, and facilitate resource usage dispute resolution procedures.</div></div>","PeriodicalId":54818,"journal":{"name":"Journal of Great Lakes Research","volume":"50 5","pages":"Article 102410"},"PeriodicalIF":2.4,"publicationDate":"2024-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142315960","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 : 2024-08-05DOI: 10.1016/j.jglr.2024.102413
R. Michael McKay , Julius Otieno Manyala , Fiona Nunan , Chrisphine Nyamweya , Fonda Jane Awuor , James Njiru
Climate change, overfishing, pollution, and habitat degradation are no longer distant threats and demand our collective action. Rising to this challenge, the Aquatic Resources and Blue Economy Conference (ARBEC) held in Kisumu, Kenya served as a call to action for sustainable aquatic practices and protection of blue economy resources. The blue economy holds much promise yet as the global community faces unprecedented environmental challenges, it’s potential hinges on our ability to make informed, science-driven decisions.
{"title":"Introduction to the special section: Aquatic resources for a sustainable future and blue economy prosperity for the African Great Lakes region","authors":"R. Michael McKay , Julius Otieno Manyala , Fiona Nunan , Chrisphine Nyamweya , Fonda Jane Awuor , James Njiru","doi":"10.1016/j.jglr.2024.102413","DOIUrl":"10.1016/j.jglr.2024.102413","url":null,"abstract":"<div><div>Climate change, overfishing, pollution, and habitat degradation are no longer distant threats and demand our collective action. Rising to this challenge, the Aquatic Resources and Blue Economy Conference (ARBEC) held in Kisumu, Kenya served as a call to action for sustainable aquatic practices and protection of blue economy resources. The blue economy holds much promise yet as the global community faces unprecedented environmental challenges, it’s potential hinges on our ability to make informed, science-driven decisions.</div></div>","PeriodicalId":54818,"journal":{"name":"Journal of Great Lakes Research","volume":"50 5","pages":"Article 102413"},"PeriodicalIF":2.4,"publicationDate":"2024-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0380133024001722/pdfft?md5=e3e8ffcc29aba53ccb8359124a501de1&pid=1-s2.0-S0380133024001722-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142315959","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}
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