An ecosystem model for evaluating the effects of introduced Pacific salmon on contaminant burdens of stream-resident fish

McGill, Lillian; Gerig, Brandon S.; Chaloner, Dominic T.; Lamberti, Gary A.

doi:10.1016/j.ecolmodel.2017.03.027

Cited by 15 publications

(10 citation statements)

References 47 publications

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“…We The challenges of using Ecotracer to simulate MeHg bioaccumulation in a food web have been noted in prior studies, indicated by large model bias (M/O ratio ¼ 0.016 to 0.056) 46 or lack of overlap between predicted and observed ranges. 47 Compared to these previous studies, our model simulation shows signicant improvement (M/O ratio ¼ 0.088 to 0.86; normalized mean bias ¼ À0.91 to À0.14, across functional groups) and we attribute the better performance to the wellcharacterized nature of the BSS food web and detailed parameterization of the direct absorption rate of lower trophic level organisms based on the body size and temperature. Compared with available MeHg observations of BSS biota, our model tends to underestimate MeHg concentrations except for two highly migratory marine mammals -Beaufort beluga (M/O ratio ¼ 1.74; normalized mean bias ¼ 0.74) and bowhead whales (M/O ratio ¼ 1.17; normalized mean bias ¼0.17) (Fig.…”

Section: Model Performance and Evaluationmentioning

confidence: 58%

“…The total amount of MeHg in each functional group is calculated based on ve processes: predator-prey interactions, direct uptake from seawater, internal metabolism, internal decay, and harvest. Walters and Christensen (2018) 45 provided a detailed description of the Ecotracer module, and this tool has been applied to simulate the dynamics of various contaminants in marine ecosystems, including Hg, 44,46,47 persistent organic pollutants, [46][47][48] microplastics, 49 and radioisotopes. 45,50,51 The intake amounts of MeHg for functional group i come from the uptake of MeHg from either water (i.e., m i B i C o in eqn (1)) or food (i.e., AE i P j¼prey Q ji C j in eqn ( 1)).…”

Section: Ecotracer Simulationmentioning

confidence: 99%

“…Prior studies that used the Ecotracer module to simulate the Hg dynamics in marine or freshwater ecosystems have all set elimination rates of MeHg in sh and lower trophic level organisms as zero due to slow excretion and inefficient internal demethylation. 44,46,47 We therefore run and compare the simulations with and without empirical elimination rates of MeHg for sh and lower trophic levels. In vivo demethylation of MeHg occurs widely in marine mammals, which transforms MeHg into labile inorganic Hg and HgSe nanoparticles.…”

Section: Ecotracer Simulationmentioning

confidence: 99%

See 2 more Smart Citations

Investigating the dynamics of methylmercury bioaccumulation in the Beaufort Sea shelf food web: a modeling perspective

Gillies

Briner

et al. 2022

Environ. Sci.: Processes Impacts

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Section: Model Performance and Evaluationmentioning

confidence: 58%

Section: Ecotracer Simulationmentioning

confidence: 99%

Section: Ecotracer Simulationmentioning

confidence: 99%

See 1 more Smart Citation

Investigating the dynamics of methylmercury bioaccumulation in the Beaufort Sea shelf food web: a modeling perspective

Gillies

Briner

et al. 2022

Environ. Sci.: Processes Impacts

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“…However, resident fish species identity was a strong mediating factor influencing the magnitude of the salmon effect. Variation in resident fish contaminant concentration could arise from variation in diet, habitat use and physiology (McGill, Gerig, Chaloner, & Lamberti, ). Contaminant bioaccumulation in fish is strongly controlled by diet, the main route of contaminant exposure in higher‐level vertebrates (Madenjian et al., ).…”

Section: Discussionmentioning

confidence: 99%

Environmental context and contaminant biotransport by Pacific salmon interact to mediate the bioaccumulation of contaminants by stream‐resident fish

Gerig

Chaloner

Janetski

et al. 2018

Journal of Applied Ecology

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The extent to which environmental context mediates the bioaccumulation of biotransported contaminants by stream‐resident organisms is poorly understood. For example, it is unclear the extent to which contaminant type, instream characteristics or resident fish identity interact to influence the uptake of contaminants deposited by Pacific salmon (Oncorhynchus spp.) during their spawning runs. To address this uncertainty, we sampled four stream‐resident fish species from 13 watersheds of the Laurentian Great Lakes in locations with and without salmon runs across a gradient of instream and watershed characteristics. We determined the polychlorinated biphenyl (PCB) and mercury (Hg) concentration along with the stable isotope ratios for salmon and stream‐resident fish. We found that stream‐resident fish PCB concentrations were higher in reaches with salmon and were positively related to δ15N. In contrast, resident fish Hg concentrations were similar or lower in reaches with salmon compared with reaches lacking salmon and either exhibited a negative or no relationship with δ15N. Based on AICc, resident fish exhibited species‐specific PCB concentrations that were positively related to salmon PCB flux. Hg burdens exhibited an interaction between fish length and salmon Hg flux—as salmon Hg inputs increased, Hg levels decreased with increasing resident fish length. Because salmon eggs are enriched in PCBs but depleted in Hg, contaminant loads of resident fish appear to be driven by consumption of salmon eggs. We found no support for models that included the mediating influence of instream or watershed factors. Synthesis and applications. Our results highlight that contaminants bioaccumulate differently depending on contaminant type, species identity and the trophic pathway to contamination. Consequently, consideration of the recipient food web and route of exposure is critical to understanding the fate of biotransported contaminants in ecosystems. The transfer of contaminants by migratory organisms represents an understudied stressor in ecology. Effective management of biotransported contaminants will require the delineation of hotspots of biotransport and implementation of best management practices to reduce inputs of salmon‐derived pollutants.

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“…Recent modeling efforts have demonstrated the ability to identify mechanisms controlling contaminant biotransport (McGill et al, 2017;Gerig et al, 2019). However, these assessments have been restricted to POPs such as PCBs, which are declining and currently banned from production (Murphy et al, 2012).…”

Section: Future Directions and Managementmentioning

confidence: 99%

Contaminant Biotransport by Pacific Salmon in the Great Lakes

et al. 2020

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In the Laurentian Great Lakes, introduced Pacific salmon (Oncorhynchus spp.) deposit resources and contaminants as carcass and gametic tissue during spawning migrations to tributaries. Such ecosystem linkages can increase growth and contaminant bioaccumulation in stream-resident fish but mechanisms driving this process remain unclear. In this mini-review, we synthesize findings from observational, experimental, and modeling studies related to Pacific salmon contaminant biotransport in the Great Lakes. First, contaminant biotransport varies among Great Lakes basins suggesting that basin-level characteristics including salmon abundance and historic contamination are important factors controlling the movement of contaminants from the lakes to tributaries. Second, stream-resident fish exposed to salmon have 24-fold higher PCB but moderately lower Hg concentrations when compared to locations without salmon. This finding is explained by differential bioaccumulation of PCB and Hg into different tissue types; analysis of salmon tissue indicates that eggs have elevated PCB and lower Hg than carcasses. Third, stream-resident fish exhibit a dietary shift and increased ration reflecting salmon egg consumption. Last, models suggest that salmon egg consumption can drive a trade-off between PCB and Hg bioaccumulation. This review identifies mechanisms controlling the transfer of salmon-derived energy potential strategies for management. Future research should be directed at identifying other biovectors and determining a list of emerging contaminants that could be subject to biotransport.

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An ecosystem model for evaluating the effects of introduced Pacific salmon on contaminant burdens of stream-resident fish

Cited by 15 publications

References 47 publications

Investigating the dynamics of methylmercury bioaccumulation in the Beaufort Sea shelf food web: a modeling perspective

Investigating the dynamics of methylmercury bioaccumulation in the Beaufort Sea shelf food web: a modeling perspective

Environmental context and contaminant biotransport by Pacific salmon interact to mediate the bioaccumulation of contaminants by stream‐resident fish

Contaminant Biotransport by Pacific Salmon in the Great Lakes

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