Timothy Ehlinger | University of Wisconsin-Milwaukee (original) (raw)
Papers by Timothy Ehlinger
Water, 2022
Urbanization results in higher stormwater loadings of pollutants such as metals and nutrients int... more Urbanization results in higher stormwater loadings of pollutants such as metals and nutrients into surface waters. This directly impacts organisms in aquatic ecosystems, including microbes. Sediment microbes are known for pollution reduction in the face of contamination, making bacterial communities an important area for bioindicator research. This study explores the pattern of bacterial responses to metal and nutrient pollution loading and seeks to evaluate whether bacterial indicators can be effective as a biomonitoring risk assessment tool for wetland ecosystems. Microcosms were built containing sediments collected from wetlands in the urbanizing Pike River watershed in southeastern Wisconsin, USA, with metals and nutrients added at 7 day intervals. Bacterial DNA was extracted from the microcosm sediments, and taxonomical profiles of bacterial communities were identified up to the genera level by sequencing 16S bacterial rRNA gene (V3–V4 region). Reduction of metals (example: 90%...
� 5 graduate students Project objectives � A model that will include stresses such as • Pollutant... more � 5 graduate students Project objectives � A model that will include stresses such as • Pollutant inputs • Watershed and water body modification • Land use changes • Chanelization and impoundments • Riparian corridor modifications � Development of a quantitative layered risk propagation from basic landscape and watershed stressors to the biotic IBI endpoints � Study the possibility of mitigating the stresses that would have the most beneficial impact on the biotic endpoints � Apply the model to another geographic region
This study demonstrates a novel application of effect-based toxicity testing for streams that may... more This study demonstrates a novel application of effect-based toxicity testing for streams that may provide indications of co-perturbation to ecological and human health. For this study, a sediment contact assay using zebrafish (Danio rerio) embryos was adapted to serve as an indicator of teratogenic stress within river sediments. Sediment samples were collected from Lake Michigan tributary watersheds. Sediment contact assay responses were then compared to prevalence of congenital heart disease (CHD) and vital statistic birth indicators aggregated from civil divisions associated with the watersheds. Significant risk relationships were detected between variation in early life-stage (ELS) endpoints of zebrafish embryos 72 h post-fertilization and the birth prevalence of human congenital heart disease, low birthweight and infant mortality. Examination of principal components of ELS endpoints suggests that variance related to embryo heart and circulatory malformations is most closely associated with human CHD prevalence. Though toxicity assays are sometimes used prospectively, this form of investigation can only be conducted retrospectively. These results support the hypothesis that bioassays normally used for ecological screening can be useful as indicators of environmental stress to humans and expand our understanding of environmental-human health linkages.
The bluegill sunfish (Lepomis macrochirus) is considered a generalist predator, adept at feeding ... more The bluegill sunfish (Lepomis macrochirus) is considered a generalist predator, adept at feeding in both the littoral and open-water habitats of North American freshwater lakes. We demonstrate adaptive intraspecific variation in morphology and foraging behaviors within single lakes. This variation appears to make individual fi'sh specialized for feeding in either the littoral or open-water habitat. Discovery of a complex polymorphism in such a well-studied species suggests that adaptive variation may be more common than is currently perceived.
Siutghiol Lake, situated on the Romanian Black Sea Coast, provides socio-economical value for the... more Siutghiol Lake, situated on the Romanian Black Sea Coast, provides socio-economical value for the surrounding area, given its various resources and uses. Seaside lakes are undergoing a significant stress from several directions, especially in the past decade, due to the enhancement of anthropic activities. Our research presents original results concerning heavy metal content determination of water and sediments by atomic absorption spectroscopy method, AAS with high resolution and continue source. In most of the sediment samples the heavy metal concentrations were above the acceptable limits stipulated of the regulation in force.
Diversity, 2021
Freshwater ecosystems are affected by anthropogenic alterations. Different studies have extensive... more Freshwater ecosystems are affected by anthropogenic alterations. Different studies have extensively studied the concentrations of metals, nutrients, and water quality as measurements of pollution in freshwater ecosystems. However, few studies have been able to link these pollutants to bioindicators as a risk assessment tool. This study aimed to examine the potential of two bioindicators, plant ecotoxicological assays and sediment bacterial taxonomic diversity, in ecological risk assessment for six freshwater constructed wetlands in a rapidly urbanizing watershed with diverse land uses. Sediment samples were collected summer, 2015 and 2017, and late summer and early fall in 2016 to conduct plant ecotoxicological assays based on plant (Lepidium, Sinapis and Sorghum) growth inhibition and identify bacterial taxonomical diversity by the 16S rRNA gene sequences. Concentrations of metals such as lead (Pb) and mercury (Hg) (using XRF), and nutrients such as nitrate and phosphate (using HAC...
Current Zoology, 2010
Sexual selection via female mate choice is thought to have played a key role in the speciation of... more Sexual selection via female mate choice is thought to have played a key role in the speciation of haplochromine cichlids, but a dominant role for visual signals in such processes has lately been called into question. In addition, the possible role of male mating preferences in haplochromine speciation has been little studied. We studied patterns of both female and male mate choice, based exclusively on visual signals, in order to evaluate potential reproductive isolation between two populations of the Lake Malawi haplochromine Labeotropheus fuelleborni. In the first experiment, females were allowed to choose between two males, one from the same population and the other allopatric with respect to the female. Females in this experiment responded more frequently to males from their own population. Similarly, the males in these trials displayed more frequently when presented with females of their own population. In the second experiment, a female was allowed to choose between two males,...
Ecology and Society, 2018
Conflict over water resources emerges from complex interactions among biophysical, social, and ec... more Conflict over water resources emerges from complex interactions among biophysical, social, and economic processes operating at multiple scales. Competing use of linked surface-groundwater (LSGW) resources is an excellent yet relatively unexplored example of such conflict. Dynamic circumstances surrounding the contested installation of a high capacity municipal well in southeastern Wisconsin were examined through the theoretical lens of adaptive governance using document analysis and open-ended key stakeholder interviews. A framework analysis method extracted 16 controlling variables from the qualitative data. These controlling variables were placed on a threshold matrix at their appropriate geospatial scale (Property, Watershed, State) and process domain (Biophysical, Economic, Social), which revealed several social-ecological feedbacks not currently addressed by management authorities. Three dynamic feedback loops were identified that explain the emergence and resolution of LSGW conflict in the case study area. Conflict emerged when processes driving new development in southeastern Wisconsin threatened to impact a highly valued groundwater dependent lake. Lake groups engaged in collective learning, utilized information networks, and displayed leadership to address the issue. However, lack of participatory avenues for dispute resolution at the scale of occurrence drove lake groups to challenge the regulatory authority of the Wisconsin Department of Natural Resources (WDNR). Through order-based legitimacy, legal resolution affected governance of LSGW resources across the state, but did little to address the underlying stakeholder values driving conflict. We conclude this system will continue to be subjected to "legal back and forth," recurrent conflict, and uncertainty for both environmental and developmental interests until a more participatory process is developed with regulatory authorities to resolve conflicts over LSGW.
Frontiers in veterinary science, 2018
Challenges calling for integrated approaches to health, such as the One Health (OH) approach, typ... more Challenges calling for integrated approaches to health, such as the One Health (OH) approach, typically arise from the intertwined spheres of humans, animals, and ecosystems constituting their environment. Initiatives addressing such wicked problems commonly consist of complex structures and dynamics. As a result of the EU COST Action (TD 1404) "Network for Evaluation of One Health" (NEOH), we propose an evaluation framework anchored in systems theory to address the intrinsic complexity of OH initiatives and regard them as subsystems of the context within which they operate. Typically, they intend to influence a system with a view to improve human, animal, and environmental health. The NEOH evaluation framework consists of four overarching elements, namely: (1) the definition of the initiative and its context, (2) the description of the theory of change with an assessment of expected and unexpected outcomes, (3) the process evaluation of operational and supporting infrastr...
Ecosphere, 2017
Predicting aquatic invasion in Adirondack lakes: a spatial analysis of lake and landscape charact... more Predicting aquatic invasion in Adirondack lakes: a spatial analysis of lake and landscape characteristics.
Frontiers in public health, 2017
One Health (OH) positions health professionals as agents for change and provides a platform to ma... more One Health (OH) positions health professionals as agents for change and provides a platform to manage determinants of health that are often not comprehensively captured in medicine or public health alone. However, due to the organization of societies and disciplines, and the sectoral allocation of resources, the development of transdisciplinary approaches requires effort and perseverance. Therefore, there is a need to provide evidence on the added value of OH for governments, researchers, funding bodies, and stakeholders. This paper outlines a conceptual framework of what OH approaches can encompass and the added values they can provide. The framework was developed during a workshop conducted by the "Network for Evaluation of One Health," an Action funded by the European Cooperation in Science and Technology. By systematically describing the various aspects of OH, we provide the basis for measuring and monitoring the integration of disciplines, sectors, and stakeholders in...
Proceedings of the National Academy of Sciences of the United States of America, 1988
International Journal of Applied Geospatial Research, 2014
Recent studies have implied the importance of incorporating configuration metrics into landscape-... more Recent studies have implied the importance of incorporating configuration metrics into landscape-aquatic ecological integrity research; however few have addressed the needs of spatial data while exploring non-linear relationships. This study investigates spatial dependence of a measure of aquatic ecological condition at two basin scales, and the spatial and non-linear role of landscape in explaining that measure across 92 watersheds in Southern Wisconsin. It hypothesizes that: (1) indicators of ecological condition have different spatial needs at subwatershed and watershed scales; (2) land cover composition, urban configuration, and landscape diversity can explain aquatic ecological integrity differently; and (3) global non-linear analysis improve local spatial statistical techniques for explaining and interpreting landscape impacts on aquatic ecological integrity. Results revealed spatial autocorrelation in the measure of aquatic ecological condition at the HUC-12 subwatershed scal...
Water Environment Research, 2007
The goal of the Use Attainability Analysis (UAA) of the Lower Des Plaines River was to upgrade th... more The goal of the Use Attainability Analysis (UAA) of the Lower Des Plaines River was to upgrade the designated "Secondary Contact Recreation and Indigenous Aquatic Life Use" to a higher use that would be commensurate with the goals of the Clean Water Act (CWA). In Illinois, the water body use in compliance with the goals of the CWA is named "General Use". The river has been extensively modified and receives most point-source and urban runoff discharges from the Chicago metropolitan area (9.5 million inhabitants). The study included an extensive assessment of the physical, chemical, biological, and bacteriological integrity status of the water body and sediments. The UAA found that the water quality situation of the river has improved significantly since the 1970s, when the Illinois Pollution Control Board defined and assigned the Secondary Contact Recreation and Indigenous Aquatic Life Use designation to the Lower Des Plaines River. The study defined and suggested a "Modified Impounded Use" for one highly modified reach, with adjusted standards for dissolved oxygen and recreation. The study also recommended adoption of the General Use standards, some of them in a modified form, for other water quality parameters. Standards for limited recreation were also developed. The UAA also outlines a suggested action plan that will bring UAA segments of the Lower Des Plaines River in compliance with UAA goals.
Proceedings of the Royal Society B: Biological Sciences, 2004
North American Journal of Fisheries Management, 2005
We used a number of different data sets and four criteria to evaluate evidence of competition and... more We used a number of different data sets and four criteria to evaluate evidence of competition and predation between walleye Sander vitreus and northern pike Esox lucius, muskellunge E. masquinongy, smallmouth bass Micropterus dolomieu, and largemouth bass M. salmoides in northern Wisconsin lakes. The four criteria were as follows: (1) indices of population abundance were inversely related, (2) two species had shared resources or one species preyed on the other, (3) competition or predation was strong enough to produce a measurable effect, and (4) experimental manipulations produced results consistent with the hypothesis of competition or predation. Using these criteria, we identified which species interact most strongly with walleyes, determined the most likely mechanism for interaction (predation, competition, or both), and characterized the effects of walleye stocking on these species. Largemouth bass was the only species that strongly interacted with walleyes: (1) indices of largemouth bass and walleye population abundance were inversely related in lakes with self-sustaining walleye populations; (2) the diet of largemouth bass included juvenile walleyes; (3) walleye growth was positively related to indices of largemouth bass abundance; and (4) survival of stocked walleyes was negatively related to indices of largemouth bass abundance, and indices of largemouth bass abundances increased as an index of walleye stocking intensity increased. A bioenergetics analysis of one lake that was stocked with 39,300 juvenile walleyes, but also has some natural reproduction of walleyes, suggested that the largemouth bass population could consume up to 82,500 juvenile walleyes per year. Our findings suggest that largemouth bass interact strongly with walleyes through predation, that they can limit the survival of stocked walleyes, and that walleye stocking can result in increased largemouth bass populations. Therefore, management goals seeking to simultaneously maximize largemouth bass and walleye populations may be unrealistic.
Water, 2022
Urbanization results in higher stormwater loadings of pollutants such as metals and nutrients int... more Urbanization results in higher stormwater loadings of pollutants such as metals and nutrients into surface waters. This directly impacts organisms in aquatic ecosystems, including microbes. Sediment microbes are known for pollution reduction in the face of contamination, making bacterial communities an important area for bioindicator research. This study explores the pattern of bacterial responses to metal and nutrient pollution loading and seeks to evaluate whether bacterial indicators can be effective as a biomonitoring risk assessment tool for wetland ecosystems. Microcosms were built containing sediments collected from wetlands in the urbanizing Pike River watershed in southeastern Wisconsin, USA, with metals and nutrients added at 7 day intervals. Bacterial DNA was extracted from the microcosm sediments, and taxonomical profiles of bacterial communities were identified up to the genera level by sequencing 16S bacterial rRNA gene (V3–V4 region). Reduction of metals (example: 90%...
� 5 graduate students Project objectives � A model that will include stresses such as • Pollutant... more � 5 graduate students Project objectives � A model that will include stresses such as • Pollutant inputs • Watershed and water body modification • Land use changes • Chanelization and impoundments • Riparian corridor modifications � Development of a quantitative layered risk propagation from basic landscape and watershed stressors to the biotic IBI endpoints � Study the possibility of mitigating the stresses that would have the most beneficial impact on the biotic endpoints � Apply the model to another geographic region
This study demonstrates a novel application of effect-based toxicity testing for streams that may... more This study demonstrates a novel application of effect-based toxicity testing for streams that may provide indications of co-perturbation to ecological and human health. For this study, a sediment contact assay using zebrafish (Danio rerio) embryos was adapted to serve as an indicator of teratogenic stress within river sediments. Sediment samples were collected from Lake Michigan tributary watersheds. Sediment contact assay responses were then compared to prevalence of congenital heart disease (CHD) and vital statistic birth indicators aggregated from civil divisions associated with the watersheds. Significant risk relationships were detected between variation in early life-stage (ELS) endpoints of zebrafish embryos 72 h post-fertilization and the birth prevalence of human congenital heart disease, low birthweight and infant mortality. Examination of principal components of ELS endpoints suggests that variance related to embryo heart and circulatory malformations is most closely associated with human CHD prevalence. Though toxicity assays are sometimes used prospectively, this form of investigation can only be conducted retrospectively. These results support the hypothesis that bioassays normally used for ecological screening can be useful as indicators of environmental stress to humans and expand our understanding of environmental-human health linkages.
The bluegill sunfish (Lepomis macrochirus) is considered a generalist predator, adept at feeding ... more The bluegill sunfish (Lepomis macrochirus) is considered a generalist predator, adept at feeding in both the littoral and open-water habitats of North American freshwater lakes. We demonstrate adaptive intraspecific variation in morphology and foraging behaviors within single lakes. This variation appears to make individual fi'sh specialized for feeding in either the littoral or open-water habitat. Discovery of a complex polymorphism in such a well-studied species suggests that adaptive variation may be more common than is currently perceived.
Siutghiol Lake, situated on the Romanian Black Sea Coast, provides socio-economical value for the... more Siutghiol Lake, situated on the Romanian Black Sea Coast, provides socio-economical value for the surrounding area, given its various resources and uses. Seaside lakes are undergoing a significant stress from several directions, especially in the past decade, due to the enhancement of anthropic activities. Our research presents original results concerning heavy metal content determination of water and sediments by atomic absorption spectroscopy method, AAS with high resolution and continue source. In most of the sediment samples the heavy metal concentrations were above the acceptable limits stipulated of the regulation in force.
Diversity, 2021
Freshwater ecosystems are affected by anthropogenic alterations. Different studies have extensive... more Freshwater ecosystems are affected by anthropogenic alterations. Different studies have extensively studied the concentrations of metals, nutrients, and water quality as measurements of pollution in freshwater ecosystems. However, few studies have been able to link these pollutants to bioindicators as a risk assessment tool. This study aimed to examine the potential of two bioindicators, plant ecotoxicological assays and sediment bacterial taxonomic diversity, in ecological risk assessment for six freshwater constructed wetlands in a rapidly urbanizing watershed with diverse land uses. Sediment samples were collected summer, 2015 and 2017, and late summer and early fall in 2016 to conduct plant ecotoxicological assays based on plant (Lepidium, Sinapis and Sorghum) growth inhibition and identify bacterial taxonomical diversity by the 16S rRNA gene sequences. Concentrations of metals such as lead (Pb) and mercury (Hg) (using XRF), and nutrients such as nitrate and phosphate (using HAC...
Current Zoology, 2010
Sexual selection via female mate choice is thought to have played a key role in the speciation of... more Sexual selection via female mate choice is thought to have played a key role in the speciation of haplochromine cichlids, but a dominant role for visual signals in such processes has lately been called into question. In addition, the possible role of male mating preferences in haplochromine speciation has been little studied. We studied patterns of both female and male mate choice, based exclusively on visual signals, in order to evaluate potential reproductive isolation between two populations of the Lake Malawi haplochromine Labeotropheus fuelleborni. In the first experiment, females were allowed to choose between two males, one from the same population and the other allopatric with respect to the female. Females in this experiment responded more frequently to males from their own population. Similarly, the males in these trials displayed more frequently when presented with females of their own population. In the second experiment, a female was allowed to choose between two males,...
Ecology and Society, 2018
Conflict over water resources emerges from complex interactions among biophysical, social, and ec... more Conflict over water resources emerges from complex interactions among biophysical, social, and economic processes operating at multiple scales. Competing use of linked surface-groundwater (LSGW) resources is an excellent yet relatively unexplored example of such conflict. Dynamic circumstances surrounding the contested installation of a high capacity municipal well in southeastern Wisconsin were examined through the theoretical lens of adaptive governance using document analysis and open-ended key stakeholder interviews. A framework analysis method extracted 16 controlling variables from the qualitative data. These controlling variables were placed on a threshold matrix at their appropriate geospatial scale (Property, Watershed, State) and process domain (Biophysical, Economic, Social), which revealed several social-ecological feedbacks not currently addressed by management authorities. Three dynamic feedback loops were identified that explain the emergence and resolution of LSGW conflict in the case study area. Conflict emerged when processes driving new development in southeastern Wisconsin threatened to impact a highly valued groundwater dependent lake. Lake groups engaged in collective learning, utilized information networks, and displayed leadership to address the issue. However, lack of participatory avenues for dispute resolution at the scale of occurrence drove lake groups to challenge the regulatory authority of the Wisconsin Department of Natural Resources (WDNR). Through order-based legitimacy, legal resolution affected governance of LSGW resources across the state, but did little to address the underlying stakeholder values driving conflict. We conclude this system will continue to be subjected to "legal back and forth," recurrent conflict, and uncertainty for both environmental and developmental interests until a more participatory process is developed with regulatory authorities to resolve conflicts over LSGW.
Frontiers in veterinary science, 2018
Challenges calling for integrated approaches to health, such as the One Health (OH) approach, typ... more Challenges calling for integrated approaches to health, such as the One Health (OH) approach, typically arise from the intertwined spheres of humans, animals, and ecosystems constituting their environment. Initiatives addressing such wicked problems commonly consist of complex structures and dynamics. As a result of the EU COST Action (TD 1404) "Network for Evaluation of One Health" (NEOH), we propose an evaluation framework anchored in systems theory to address the intrinsic complexity of OH initiatives and regard them as subsystems of the context within which they operate. Typically, they intend to influence a system with a view to improve human, animal, and environmental health. The NEOH evaluation framework consists of four overarching elements, namely: (1) the definition of the initiative and its context, (2) the description of the theory of change with an assessment of expected and unexpected outcomes, (3) the process evaluation of operational and supporting infrastr...
Ecosphere, 2017
Predicting aquatic invasion in Adirondack lakes: a spatial analysis of lake and landscape charact... more Predicting aquatic invasion in Adirondack lakes: a spatial analysis of lake and landscape characteristics.
Frontiers in public health, 2017
One Health (OH) positions health professionals as agents for change and provides a platform to ma... more One Health (OH) positions health professionals as agents for change and provides a platform to manage determinants of health that are often not comprehensively captured in medicine or public health alone. However, due to the organization of societies and disciplines, and the sectoral allocation of resources, the development of transdisciplinary approaches requires effort and perseverance. Therefore, there is a need to provide evidence on the added value of OH for governments, researchers, funding bodies, and stakeholders. This paper outlines a conceptual framework of what OH approaches can encompass and the added values they can provide. The framework was developed during a workshop conducted by the "Network for Evaluation of One Health," an Action funded by the European Cooperation in Science and Technology. By systematically describing the various aspects of OH, we provide the basis for measuring and monitoring the integration of disciplines, sectors, and stakeholders in...
Proceedings of the National Academy of Sciences of the United States of America, 1988
International Journal of Applied Geospatial Research, 2014
Recent studies have implied the importance of incorporating configuration metrics into landscape-... more Recent studies have implied the importance of incorporating configuration metrics into landscape-aquatic ecological integrity research; however few have addressed the needs of spatial data while exploring non-linear relationships. This study investigates spatial dependence of a measure of aquatic ecological condition at two basin scales, and the spatial and non-linear role of landscape in explaining that measure across 92 watersheds in Southern Wisconsin. It hypothesizes that: (1) indicators of ecological condition have different spatial needs at subwatershed and watershed scales; (2) land cover composition, urban configuration, and landscape diversity can explain aquatic ecological integrity differently; and (3) global non-linear analysis improve local spatial statistical techniques for explaining and interpreting landscape impacts on aquatic ecological integrity. Results revealed spatial autocorrelation in the measure of aquatic ecological condition at the HUC-12 subwatershed scal...
Water Environment Research, 2007
The goal of the Use Attainability Analysis (UAA) of the Lower Des Plaines River was to upgrade th... more The goal of the Use Attainability Analysis (UAA) of the Lower Des Plaines River was to upgrade the designated "Secondary Contact Recreation and Indigenous Aquatic Life Use" to a higher use that would be commensurate with the goals of the Clean Water Act (CWA). In Illinois, the water body use in compliance with the goals of the CWA is named "General Use". The river has been extensively modified and receives most point-source and urban runoff discharges from the Chicago metropolitan area (9.5 million inhabitants). The study included an extensive assessment of the physical, chemical, biological, and bacteriological integrity status of the water body and sediments. The UAA found that the water quality situation of the river has improved significantly since the 1970s, when the Illinois Pollution Control Board defined and assigned the Secondary Contact Recreation and Indigenous Aquatic Life Use designation to the Lower Des Plaines River. The study defined and suggested a "Modified Impounded Use" for one highly modified reach, with adjusted standards for dissolved oxygen and recreation. The study also recommended adoption of the General Use standards, some of them in a modified form, for other water quality parameters. Standards for limited recreation were also developed. The UAA also outlines a suggested action plan that will bring UAA segments of the Lower Des Plaines River in compliance with UAA goals.
Proceedings of the Royal Society B: Biological Sciences, 2004
North American Journal of Fisheries Management, 2005
We used a number of different data sets and four criteria to evaluate evidence of competition and... more We used a number of different data sets and four criteria to evaluate evidence of competition and predation between walleye Sander vitreus and northern pike Esox lucius, muskellunge E. masquinongy, smallmouth bass Micropterus dolomieu, and largemouth bass M. salmoides in northern Wisconsin lakes. The four criteria were as follows: (1) indices of population abundance were inversely related, (2) two species had shared resources or one species preyed on the other, (3) competition or predation was strong enough to produce a measurable effect, and (4) experimental manipulations produced results consistent with the hypothesis of competition or predation. Using these criteria, we identified which species interact most strongly with walleyes, determined the most likely mechanism for interaction (predation, competition, or both), and characterized the effects of walleye stocking on these species. Largemouth bass was the only species that strongly interacted with walleyes: (1) indices of largemouth bass and walleye population abundance were inversely related in lakes with self-sustaining walleye populations; (2) the diet of largemouth bass included juvenile walleyes; (3) walleye growth was positively related to indices of largemouth bass abundance; and (4) survival of stocked walleyes was negatively related to indices of largemouth bass abundance, and indices of largemouth bass abundances increased as an index of walleye stocking intensity increased. A bioenergetics analysis of one lake that was stocked with 39,300 juvenile walleyes, but also has some natural reproduction of walleyes, suggested that the largemouth bass population could consume up to 82,500 juvenile walleyes per year. Our findings suggest that largemouth bass interact strongly with walleyes through predation, that they can limit the survival of stocked walleyes, and that walleye stocking can result in increased largemouth bass populations. Therefore, management goals seeking to simultaneously maximize largemouth bass and walleye populations may be unrealistic.