Pub Date : 2020-12-17DOI: 10.1080/24705357.2020.1855086
Marcía N Snyder, Nathan H Schumaker, Jason B Dunham, Matthew L Keefer, Peter Leinenbach, Allen Brookes, John Palmer, Jennifer Wu, Druscilla Keenan, Joseph L Ebersole
Diadromous fish populations face multiple challenges along their migratory routes. These challenges include suboptimal water quality, harvest, and barriers to longitudinal and lateral connectivity. Interactions among factors influencing migration success make it challenging to assess management options for improving migratory fish conditions along riverine migration corridors. We describe a spatially explicit simulation model that integrates complex individual behaviors of fall-run Chinook Salmon (Oncorhynchus tshawytscha) and summer-run steelhead trout (O. mykiss) during migration, responds to variable habitat conditions over a large extent of the Columbia River, and links migration corridor conditions to fish condition outcomes. The model is built around a mechanistic behavioral decision tree that drives individual interactions of fish within their simulated environments. By simulating several thermalscapes with alternative scenarios of thermal refuge availability, we examined how behavioral thermoregulation in cold-water refuges influenced migrating fish conditions. Outcomes of the migration corridor simulation model show that cold-water refuges can provide relief from exposure to high water temperatures, but do not substantially contribute to energy conservation by migrating adults. Simulated cooling of the Columbia River decreased reliance on cold-water refuges and there were slight reductions in migratory energy expenditure. This modeling of simulated thermalscapes provides a framework for assessing the contribution of cold-water refuges to the success of migrating fishes, but any final determination will depend on analyzing fish survival and health for their entire migration, water temperature management goals and species recovery targets.
{"title":"Assessing contributions of cold-water refuges to reproductive migration corridor conditions for adult Chinook Salmon and steelhead trout in the Columbia River, USA.","authors":"Marcía N Snyder, Nathan H Schumaker, Jason B Dunham, Matthew L Keefer, Peter Leinenbach, Allen Brookes, John Palmer, Jennifer Wu, Druscilla Keenan, Joseph L Ebersole","doi":"10.1080/24705357.2020.1855086","DOIUrl":"https://doi.org/10.1080/24705357.2020.1855086","url":null,"abstract":"<p><p>Diadromous fish populations face multiple challenges along their migratory routes. These challenges include suboptimal water quality, harvest, and barriers to longitudinal and lateral connectivity. Interactions among factors influencing migration success make it challenging to assess management options for improving migratory fish conditions along riverine migration corridors. We describe a spatially explicit simulation model that integrates complex individual behaviors of fall-run Chinook Salmon (<i>Oncorhynchus tshawytscha</i>) and summer-run steelhead trout (<i>O. mykiss</i>) during migration, responds to variable habitat conditions over a large extent of the Columbia River, and links migration corridor conditions to fish condition outcomes. The model is built around a mechanistic behavioral decision tree that drives individual interactions of fish within their simulated environments. By simulating several thermalscapes with alternative scenarios of thermal refuge availability, we examined how behavioral thermoregulation in cold-water refuges influenced migrating fish conditions. Outcomes of the migration corridor simulation model show that cold-water refuges can provide relief from exposure to high water temperatures, but do not substantially contribute to energy conservation by migrating adults. Simulated cooling of the Columbia River decreased reliance on cold-water refuges and there were slight reductions in migratory energy expenditure. This modeling of simulated thermalscapes provides a framework for assessing the contribution of cold-water refuges to the success of migrating fishes, but any final determination will depend on analyzing fish survival and health for their entire migration, water temperature management goals and species recovery targets.</p>","PeriodicalId":93201,"journal":{"name":"Journal of ecohydraulics","volume":"1 ","pages":"1-13"},"PeriodicalIF":0.0,"publicationDate":"2020-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/24705357.2020.1855086","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"38908502","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-12-17DOI: 10.1080/24705357.2020.1858197
Jana Carus, C. Arndt, T. Bouma, B. Schröder, M. Paul
Abstract Seagrass meadows have disappeared on many coastal sections due to anthropogenic disturbances, diseases, and/or eutrophication. To facilitate informed seagrass restoration, we i) quantified the hydrodynamic dislodgement thresholds for newly transplanted Z. marina shoots, and ii) tested the effect of artificial seagrass (ASG) as a hydrodynamic protection measure. Experiments were carried out by planting Z. marina rhizomes with living shoots into a sediment bed and exposing them to a range of wave and current conditions in a flume. The use of ASG significantly reduced wave height, as well as current velocity. The applied waves led to the development of ripples whereas currents led to erosion of the sediment bed. The number of shoots that were uprooted and dislodged increased with increasing bed shear stress and erosion. By reducing bed shear stress, the ASG raised the input current velocity threshold, which the transplanted shoots were able to withstand. The present study offers insight into the effect of artificial seagrass (ASG) on wave and current attenuation, as well as sediment erosion and shoot dislodgement. Our results help to inform the setting of hydrodynamic thresholds for the early establishment of Z. marina and to define the improvement of hydrodynamic conditions by ASG.
{"title":"Effect of artificial seagrass on hydrodynamic thresholds for the early establishment of Zostera marina","authors":"Jana Carus, C. Arndt, T. Bouma, B. Schröder, M. Paul","doi":"10.1080/24705357.2020.1858197","DOIUrl":"https://doi.org/10.1080/24705357.2020.1858197","url":null,"abstract":"Abstract Seagrass meadows have disappeared on many coastal sections due to anthropogenic disturbances, diseases, and/or eutrophication. To facilitate informed seagrass restoration, we i) quantified the hydrodynamic dislodgement thresholds for newly transplanted Z. marina shoots, and ii) tested the effect of artificial seagrass (ASG) as a hydrodynamic protection measure. Experiments were carried out by planting Z. marina rhizomes with living shoots into a sediment bed and exposing them to a range of wave and current conditions in a flume. The use of ASG significantly reduced wave height, as well as current velocity. The applied waves led to the development of ripples whereas currents led to erosion of the sediment bed. The number of shoots that were uprooted and dislodged increased with increasing bed shear stress and erosion. By reducing bed shear stress, the ASG raised the input current velocity threshold, which the transplanted shoots were able to withstand. The present study offers insight into the effect of artificial seagrass (ASG) on wave and current attenuation, as well as sediment erosion and shoot dislodgement. Our results help to inform the setting of hydrodynamic thresholds for the early establishment of Z. marina and to define the improvement of hydrodynamic conditions by ASG.","PeriodicalId":93201,"journal":{"name":"Journal of ecohydraulics","volume":"20 1","pages":"17 - 27"},"PeriodicalIF":0.0,"publicationDate":"2020-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79994693","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-12-17DOI: 10.1080/24705357.2020.1858724
M. Forcellini, L. Plichard, S. Dolédec, S. Mérigoux, J. Olivier, S. Cauvy‐Fraunié, N. Lamouroux
Abstract The transferability of hydraulic microhabitat selection models among rivers has been largely debated. It can influence management decisions such as restoration measures or environmental flow definitions. We updated microhabitat selection models for 258 macroinvertebrate taxa, with 141 species, collected in 2128 Surber or Hess samples during 91 surveys (sites × dates) distributed in eleven small streams to large rivers of Germany and France. We compared microhabitat selection for four hydraulic variables, developed using mixed-effects models that account for the overdispersion of observed abundance, partly due to spatial aggregation. Models based on bed shear stress, water column velocity and Froude number showed comparable results and were stronger than models for water depth. For these velocity-related variables, 61–78% of models were significant and revealed variable response forms among taxa. The explanatory power of “average” microhabitat selection models, with response forms common to all surveys, was 78–83% of the explanatory power of more detailed models with variable response forms. Significant associations with biological traits such as locomotion, relation to substrate or food types suggested that microhabitat selection results from general biological processes. Our results indicate a high degree of transferability and can be useful in many basic and applied ecological studies.
{"title":"Microhabitat selection by macroinvertebrates: generality among rivers and functional interpretation","authors":"M. Forcellini, L. Plichard, S. Dolédec, S. Mérigoux, J. Olivier, S. Cauvy‐Fraunié, N. Lamouroux","doi":"10.1080/24705357.2020.1858724","DOIUrl":"https://doi.org/10.1080/24705357.2020.1858724","url":null,"abstract":"Abstract The transferability of hydraulic microhabitat selection models among rivers has been largely debated. It can influence management decisions such as restoration measures or environmental flow definitions. We updated microhabitat selection models for 258 macroinvertebrate taxa, with 141 species, collected in 2128 Surber or Hess samples during 91 surveys (sites × dates) distributed in eleven small streams to large rivers of Germany and France. We compared microhabitat selection for four hydraulic variables, developed using mixed-effects models that account for the overdispersion of observed abundance, partly due to spatial aggregation. Models based on bed shear stress, water column velocity and Froude number showed comparable results and were stronger than models for water depth. For these velocity-related variables, 61–78% of models were significant and revealed variable response forms among taxa. The explanatory power of “average” microhabitat selection models, with response forms common to all surveys, was 78–83% of the explanatory power of more detailed models with variable response forms. Significant associations with biological traits such as locomotion, relation to substrate or food types suggested that microhabitat selection results from general biological processes. Our results indicate a high degree of transferability and can be useful in many basic and applied ecological studies.","PeriodicalId":93201,"journal":{"name":"Journal of ecohydraulics","volume":"6 1","pages":"28 - 41"},"PeriodicalIF":0.0,"publicationDate":"2020-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74453420","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-12-06DOI: 10.1080/24705357.2020.1834884
F. Grasso, A. Carlier, P. Cugier, R. Verney, M. Marzloff
Abstract In coastal environments, strong feedback can exist between benthic fauna and sediment dynamics. Benthic populations can modify sediment dynamics through biofiltration and bioturbation, while hydro- and sediment dynamics directly determine local environmental conditions for benthic organisms. However, these complex feedbacks are difficult to study in situ. Here, we carried out mesocosm experiments to characterize the effects of a benthic species (the gastropod Crepidula fornicata) on mud dynamics under hydrodynamic conditions representative of their natural habitat. Different experimental tests related to the inclusion (or not) of dead or live crepidula reveal that biofiltration can increase particle settling up to 40%. Flocculation, which is strengthened by organic matter enrichment in shell beds, also substantially increases particle settling. Thus, both processes enhance sedimentation above live crepidula habitats. Furthermore, these experiments highlight serious technical, physical and biological challenges that have to be tackled for properly investigating bio-physical interactions.
{"title":"Influence of Crepidula fornicata on suspended particle dynamics in coastal systems: a mesocosm experimental study","authors":"F. Grasso, A. Carlier, P. Cugier, R. Verney, M. Marzloff","doi":"10.1080/24705357.2020.1834884","DOIUrl":"https://doi.org/10.1080/24705357.2020.1834884","url":null,"abstract":"Abstract In coastal environments, strong feedback can exist between benthic fauna and sediment dynamics. Benthic populations can modify sediment dynamics through biofiltration and bioturbation, while hydro- and sediment dynamics directly determine local environmental conditions for benthic organisms. However, these complex feedbacks are difficult to study in situ. Here, we carried out mesocosm experiments to characterize the effects of a benthic species (the gastropod Crepidula fornicata) on mud dynamics under hydrodynamic conditions representative of their natural habitat. Different experimental tests related to the inclusion (or not) of dead or live crepidula reveal that biofiltration can increase particle settling up to 40%. Flocculation, which is strengthened by organic matter enrichment in shell beds, also substantially increases particle settling. Thus, both processes enhance sedimentation above live crepidula habitats. Furthermore, these experiments highlight serious technical, physical and biological challenges that have to be tackled for properly investigating bio-physical interactions.","PeriodicalId":93201,"journal":{"name":"Journal of ecohydraulics","volume":"63 1","pages":"26 - 37"},"PeriodicalIF":0.0,"publicationDate":"2020-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77101960","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-11-20DOI: 10.1080/24705357.2020.1830723
P. Romero-Gomez, M. Lång, S. Weissenberger
Abstract The construction, rehabilitation and re-licensing of hydropower stations must nowadays fulfill strict demands for fish protection, particularly those related to enhanced turbine passage survival rates of downstream migratory species. In an analogy to the efficiency curves of a water turbine represented on a hill chart, the bio-hill chart introduced herein depicts the relationships between the operating conditions (i.e., discharge and head) and the potential survival rate of migratory fish passing through the turbine. The bio-hill chart applies over the entire operating range of the machine, which is a step forward with respect to previous works that determined hydraulic-biological evaluations for only a few operating points. The elaboration of a bio-hill chart involves two steps: (i) the calculation of turbine flows for each operating point and (ii) the corresponding evaluation of fish friendliness. The flow conditions are determined via computational fluid dynamics simulations. The calculation of fish friendliness relies on modelling approaches to determine mortality risks associated with collision on rotating blades and rapid decompression. We thoroughly describe the process to elaborate the bio-hill chart for juvenile salmonid species, as well as its implementation in a Kaplan turbine. The bio-hill chart represents a first approximation for determining those operating conditions that may mitigate fish mortality risks (i.e., maximize fish friendliness) and for quantitatively establishing the inevitable trade-off that exists between the hydraulic and environmental demands of hydropower generation.
{"title":"The bio-hill chart of a Kaplan turbine","authors":"P. Romero-Gomez, M. Lång, S. Weissenberger","doi":"10.1080/24705357.2020.1830723","DOIUrl":"https://doi.org/10.1080/24705357.2020.1830723","url":null,"abstract":"Abstract The construction, rehabilitation and re-licensing of hydropower stations must nowadays fulfill strict demands for fish protection, particularly those related to enhanced turbine passage survival rates of downstream migratory species. In an analogy to the efficiency curves of a water turbine represented on a hill chart, the bio-hill chart introduced herein depicts the relationships between the operating conditions (i.e., discharge and head) and the potential survival rate of migratory fish passing through the turbine. The bio-hill chart applies over the entire operating range of the machine, which is a step forward with respect to previous works that determined hydraulic-biological evaluations for only a few operating points. The elaboration of a bio-hill chart involves two steps: (i) the calculation of turbine flows for each operating point and (ii) the corresponding evaluation of fish friendliness. The flow conditions are determined via computational fluid dynamics simulations. The calculation of fish friendliness relies on modelling approaches to determine mortality risks associated with collision on rotating blades and rapid decompression. We thoroughly describe the process to elaborate the bio-hill chart for juvenile salmonid species, as well as its implementation in a Kaplan turbine. The bio-hill chart represents a first approximation for determining those operating conditions that may mitigate fish mortality risks (i.e., maximize fish friendliness) and for quantitatively establishing the inevitable trade-off that exists between the hydraulic and environmental demands of hydropower generation.","PeriodicalId":93201,"journal":{"name":"Journal of ecohydraulics","volume":"9 1","pages":"94 - 110"},"PeriodicalIF":0.0,"publicationDate":"2020-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86434269","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-11-19DOI: 10.1080/24705357.2020.1830002
D. Rosero‐López, E. Cowen, M. Walter, B. Bièvre, D. González‐Zeas, A. Flecker, R. Osorio, O. Dangles
Abstract Controlled in-stream flow manipulations are challenging but necessary to implement to assess the consequences of real-world flow alterations on aquatic ecosystems. We designed a double v-notch weir system, which was first prototype-tested in a laboratory flume and then in the field. The device diverted instantaneous flows proportionally in a robust way (e.g., 10% of flow in the stream main channel and 90% of flow into the diversion channel). We tested diversions systematically and evaluated how well flows matched our target flow-percentages. This is one of the first ecohydraulic structures designed and tested to experimentally manipulate environmental flows in small upland streams.
{"title":"Design of a paired-weir system for experimental manipulation of environmental flows in streams","authors":"D. Rosero‐López, E. Cowen, M. Walter, B. Bièvre, D. González‐Zeas, A. Flecker, R. Osorio, O. Dangles","doi":"10.1080/24705357.2020.1830002","DOIUrl":"https://doi.org/10.1080/24705357.2020.1830002","url":null,"abstract":"Abstract Controlled in-stream flow manipulations are challenging but necessary to implement to assess the consequences of real-world flow alterations on aquatic ecosystems. We designed a double v-notch weir system, which was first prototype-tested in a laboratory flume and then in the field. The device diverted instantaneous flows proportionally in a robust way (e.g., 10% of flow in the stream main channel and 90% of flow into the diversion channel). We tested diversions systematically and evaluated how well flows matched our target flow-percentages. This is one of the first ecohydraulic structures designed and tested to experimentally manipulate environmental flows in small upland streams.","PeriodicalId":93201,"journal":{"name":"Journal of ecohydraulics","volume":"11 1","pages":"81 - 88"},"PeriodicalIF":0.0,"publicationDate":"2020-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78192119","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-11-10DOI: 10.1080/24705357.2020.1835566
R. Tinoco, A. F. Prada, A. George, B. H. Stahlschmidt, P. R. Jackson, D. Chapman
Abstract Aquatic vegetation can provide habitat and refuge for a variety of species in streams. However, the flow features generated by submerged patches of vegetation can also pose a challenge for fish larvae. We conducted a series of experiments with live grass carp larvae (starting ∼50 h post hatch) in a laboratory racetrack flume, using a submerged array of rigid cylinders to mimic vegetation. We used particle image velocimetry to characterize the flow field, and particle tracking velocimetry to obtain position and displacement of the fish. Four speeds and two submergence ratios were investigated. In contrast with previous studies with grass carp eggs, our data showed an active response from larvae to determine their position. Our study shows that: (1) mean velocity by itself is not a reliable predictor, as some larvae will seemingly prefer to be in areas of higher speeds with lower shear and turbulence, (2) turbulence characteristics can be used to identify areas avoided by larvae, (3) turbulence length scales are relevant to determine spatial distribution of larvae and their swimming capabilities within and above vegetated patches and similar roughness elements in streams. These findings can inform the design of monitoring and control strategies in rivers based on turbulence and turbulence scales generated by natural and man-made instream structures.
{"title":"Identifying turbulence features hindering swimming capabilities of grass carp larvae (Ctenopharyngodon idella) through submerged vegetation","authors":"R. Tinoco, A. F. Prada, A. George, B. H. Stahlschmidt, P. R. Jackson, D. Chapman","doi":"10.1080/24705357.2020.1835566","DOIUrl":"https://doi.org/10.1080/24705357.2020.1835566","url":null,"abstract":"Abstract Aquatic vegetation can provide habitat and refuge for a variety of species in streams. However, the flow features generated by submerged patches of vegetation can also pose a challenge for fish larvae. We conducted a series of experiments with live grass carp larvae (starting ∼50 h post hatch) in a laboratory racetrack flume, using a submerged array of rigid cylinders to mimic vegetation. We used particle image velocimetry to characterize the flow field, and particle tracking velocimetry to obtain position and displacement of the fish. Four speeds and two submergence ratios were investigated. In contrast with previous studies with grass carp eggs, our data showed an active response from larvae to determine their position. Our study shows that: (1) mean velocity by itself is not a reliable predictor, as some larvae will seemingly prefer to be in areas of higher speeds with lower shear and turbulence, (2) turbulence characteristics can be used to identify areas avoided by larvae, (3) turbulence length scales are relevant to determine spatial distribution of larvae and their swimming capabilities within and above vegetated patches and similar roughness elements in streams. These findings can inform the design of monitoring and control strategies in rivers based on turbulence and turbulence scales generated by natural and man-made instream structures.","PeriodicalId":93201,"journal":{"name":"Journal of ecohydraulics","volume":"118 2-3 1","pages":"4 - 16"},"PeriodicalIF":0.0,"publicationDate":"2020-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78146397","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-09-29DOI: 10.1080/24705357.2020.1818642
An V. Vu, L. Baumgartner, M. Mallen‐Cooper, J. Howitt, W. Robinson, N. So, I. Cowx
Abstract Diadromous fishes, those that migrate between fresh and marine waters, are among the most vulnerable species to river infrastructural development. These fish need to move between fresh water and the sea, so any obstruction to migration can block access to critical habitat areas. The Lower Mekong Basin (LMB) is experiencing an unprecedented boom in river development, with many dams and irrigation schemes being installed. Although general patterns of fish migration are known in the LMB, there is relatively little information on diadromous fish migration, so the overall impacts of river development on their population status is likely underestimated for many species. In this study, we reviewed the available information for over one thousand Mekong fish species to identify evidence for diadromy. Our results found that diadromy is likely a more common life history trait in the LMB than previously assumed. For instance, 61 of the 1136 Mekong fish species assessed exhibit diadromous traits (44 amphidromous species, 9 anadromous species, and 8 catadromous species). Many of these species are known to migrate relatively long distances, connecting with the Mekong estuary to some extent to complete their life cycles. Based on routine fish catch monitoring data, these suspected diadromous fishes contributed around 3% to the total catch across the basin and included a number of endemic species of significant economic value. Riverine development must therefore proceed in a balanced manner to protect diadromous species diversity and associated fisheries resources, whilst also meeting food and energy demands in the region.
{"title":"Diadromy in a large tropical river, the Mekong: more common than assumed, with greater implications for management","authors":"An V. Vu, L. Baumgartner, M. Mallen‐Cooper, J. Howitt, W. Robinson, N. So, I. Cowx","doi":"10.1080/24705357.2020.1818642","DOIUrl":"https://doi.org/10.1080/24705357.2020.1818642","url":null,"abstract":"Abstract Diadromous fishes, those that migrate between fresh and marine waters, are among the most vulnerable species to river infrastructural development. These fish need to move between fresh water and the sea, so any obstruction to migration can block access to critical habitat areas. The Lower Mekong Basin (LMB) is experiencing an unprecedented boom in river development, with many dams and irrigation schemes being installed. Although general patterns of fish migration are known in the LMB, there is relatively little information on diadromous fish migration, so the overall impacts of river development on their population status is likely underestimated for many species. In this study, we reviewed the available information for over one thousand Mekong fish species to identify evidence for diadromy. Our results found that diadromy is likely a more common life history trait in the LMB than previously assumed. For instance, 61 of the 1136 Mekong fish species assessed exhibit diadromous traits (44 amphidromous species, 9 anadromous species, and 8 catadromous species). Many of these species are known to migrate relatively long distances, connecting with the Mekong estuary to some extent to complete their life cycles. Based on routine fish catch monitoring data, these suspected diadromous fishes contributed around 3% to the total catch across the basin and included a number of endemic species of significant economic value. Riverine development must therefore proceed in a balanced manner to protect diadromous species diversity and associated fisheries resources, whilst also meeting food and energy demands in the region.","PeriodicalId":93201,"journal":{"name":"Journal of ecohydraulics","volume":"159 1","pages":"38 - 50"},"PeriodicalIF":0.0,"publicationDate":"2020-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86384059","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-09-25DOI: 10.1080/24705357.2020.1813057
R. Casas‐Mulet, D. Vanzo, Ana Adeva-Bustos, Camille J. Macnaughton, M. Stewardson, G. Pasternack, E. Enders, F. Dyer
Abstract Interdisciplinary approaches are required to tackle complex environmental issues as freshwater ecosystems face unprecedented pressures globally. The emerging Ecohydraulics field of research should, therefore, take steps towards developing true interdisciplinarity to adapt to a continuing changing world. This study contributes to the ongoing discussion on interdisciplinarity in Ecohydraulics and shapes its growth by identifying key actions, actors and implementation strategies that can strengthen it. Based on an online questionnaire and a workshop involving over 150 early and established careers, we present a list of 20 prioritised actions that will help engage the research community towards specific goals and will result in increased interdisciplinary outcomes. While early career researchers (ECRs) have taken the lead on creating this roadmap, its implementation should be a joint responsibility of both ECRs, established career scientists, groups, and institutions within Ecohydraulics. The list of identified actions and assigned responsibility should, therefore, be considered a conversation starter. Continued revision of the here-stated approaches will be required in the future as the field of research and its community progresses. With this contribution, we resume a critical reflection on where the Ecohydraulics field of research and community stand today and suggest where resources should be invested in the long-term to consolidate the inherent interdisciplinarity in Ecohydraulics.
{"title":"How to strengthen interdisciplinarity in ecohydraulics? Outcomes from ISE 2018","authors":"R. Casas‐Mulet, D. Vanzo, Ana Adeva-Bustos, Camille J. Macnaughton, M. Stewardson, G. Pasternack, E. Enders, F. Dyer","doi":"10.1080/24705357.2020.1813057","DOIUrl":"https://doi.org/10.1080/24705357.2020.1813057","url":null,"abstract":"Abstract Interdisciplinary approaches are required to tackle complex environmental issues as freshwater ecosystems face unprecedented pressures globally. The emerging Ecohydraulics field of research should, therefore, take steps towards developing true interdisciplinarity to adapt to a continuing changing world. This study contributes to the ongoing discussion on interdisciplinarity in Ecohydraulics and shapes its growth by identifying key actions, actors and implementation strategies that can strengthen it. Based on an online questionnaire and a workshop involving over 150 early and established careers, we present a list of 20 prioritised actions that will help engage the research community towards specific goals and will result in increased interdisciplinary outcomes. While early career researchers (ECRs) have taken the lead on creating this roadmap, its implementation should be a joint responsibility of both ECRs, established career scientists, groups, and institutions within Ecohydraulics. The list of identified actions and assigned responsibility should, therefore, be considered a conversation starter. Continued revision of the here-stated approaches will be required in the future as the field of research and its community progresses. With this contribution, we resume a critical reflection on where the Ecohydraulics field of research and community stand today and suggest where resources should be invested in the long-term to consolidate the inherent interdisciplinarity in Ecohydraulics.","PeriodicalId":93201,"journal":{"name":"Journal of ecohydraulics","volume":"753 1","pages":"1 - 12"},"PeriodicalIF":0.0,"publicationDate":"2020-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76879419","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-09-17DOI: 10.1080/24705357.2020.1790047
C. Judes, V. Gouraud, Hervé Capra, Anthony Maire, A. Barillier, Nicolas, Lamouroux
Abstract Hydropeaking corresponds to rapid artificial discharge variations, designed to address sub-daily peaks in electricity demand. It generates rapid changes in physical habitat (e.g., flow velocity and water depth) with potential impacts on stream assemblages. For assessing the generality of hydropeaking effects on fish assemblages, we present an original combination of spatial (among 45 reaches, including six groups of nearby reaches) and temporal (over 3-17 years) analyses of these effects. Our analyses involved descriptions of natural and artificial hydraulic variations in reaches, obtained after translating hourly discharge data into hydraulics. We found that the influence of hydropeaking was secondary compared to well-known spatial variations in fish assemblage structure along longitudinal gradients, and negative influences of floods on annual densities. However, the spatial and temporal analyses consistently suggested that hydropeaking may disfavour fish species typical of medium-sized streams relative to species of headwater streams (Salmo trutta, Phoxinus phoxinus, Cottus gobio). The magnitude of hydropeaking effects observed here, as well as an apparent weaker effect of ramping rates than the frequency of hydropeaks, may be due to lower ramping rates in our data set than in other studies.
{"title":"Consistent but secondary influence of hydropeaking on stream fish assemblages in space and time","authors":"C. Judes, V. Gouraud, Hervé Capra, Anthony Maire, A. Barillier, Nicolas, Lamouroux","doi":"10.1080/24705357.2020.1790047","DOIUrl":"https://doi.org/10.1080/24705357.2020.1790047","url":null,"abstract":"Abstract Hydropeaking corresponds to rapid artificial discharge variations, designed to address sub-daily peaks in electricity demand. It generates rapid changes in physical habitat (e.g., flow velocity and water depth) with potential impacts on stream assemblages. For assessing the generality of hydropeaking effects on fish assemblages, we present an original combination of spatial (among 45 reaches, including six groups of nearby reaches) and temporal (over 3-17 years) analyses of these effects. Our analyses involved descriptions of natural and artificial hydraulic variations in reaches, obtained after translating hourly discharge data into hydraulics. We found that the influence of hydropeaking was secondary compared to well-known spatial variations in fish assemblage structure along longitudinal gradients, and negative influences of floods on annual densities. However, the spatial and temporal analyses consistently suggested that hydropeaking may disfavour fish species typical of medium-sized streams relative to species of headwater streams (Salmo trutta, Phoxinus phoxinus, Cottus gobio). The magnitude of hydropeaking effects observed here, as well as an apparent weaker effect of ramping rates than the frequency of hydropeaks, may be due to lower ramping rates in our data set than in other studies.","PeriodicalId":93201,"journal":{"name":"Journal of ecohydraulics","volume":"38 1","pages":"157 - 171"},"PeriodicalIF":0.0,"publicationDate":"2020-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85949654","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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