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Chavarie L, Honkanen HM, Newton M, Lilly JM, Greetham HR, Adams CE. The benefits of merging passive and active tracking approaches: New insights into riverine migration by salmonid smolts. Ecosphere 2022. [DOI: 10.1002/ecs2.4045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Affiliation(s)
- Louise Chavarie
- Faculty of Environmental Sciences and Natural Resource Management Norwegian University of Life Sciences Ås Norway
- Scottish Centre for Ecology and the Natural Environment, IBAHCM University of Glasgow Glasgow UK
| | - Hannele M. Honkanen
- Scottish Centre for Ecology and the Natural Environment, IBAHCM University of Glasgow Glasgow UK
| | - Matthew Newton
- Scottish Centre for Ecology and the Natural Environment, IBAHCM University of Glasgow Glasgow UK
| | - Jessie M. Lilly
- Scottish Centre for Ecology and the Natural Environment, IBAHCM University of Glasgow Glasgow UK
| | - Hannah R. Greetham
- Scottish Centre for Ecology and the Natural Environment, IBAHCM University of Glasgow Glasgow UK
| | - Colin E. Adams
- Scottish Centre for Ecology and the Natural Environment, IBAHCM University of Glasgow Glasgow UK
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2
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Wasserman RJ, Cuthbert RN, Alexander ME, Dalu T. Shifting interaction strength between estuarine mysid species across a temperature gradient. MARINE ENVIRONMENTAL RESEARCH 2018; 140:390-393. [PMID: 30054133 DOI: 10.1016/j.marenvres.2018.07.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Revised: 06/26/2018] [Accepted: 07/20/2018] [Indexed: 06/08/2023]
Abstract
In many coastal regions, mean coastal atmospheric and water temperatures are projected to shift as climate change ensues. Interaction strengths between organisms are likely to change along with environmental changes, given interspecific heterogeneity in responses to physico-chemical variables. Biological interaction outcomes have the potential to alter food web production and trophic level biomass distribution. This is particularly pertinent for key species that are either abundant or play disproportionately large roles in ecosystem processes. Using a functional response approach, we quantified the effects of shifting temperatures on interactions between key mysid species-sympatric in their distribution across a biogeographic transition zone along the east coast of South Africa. The Rhopalophthalmus terranatalis functional response type toward Mesopodopsis wooldridgei prey was independent of temperature, with all treatments producing Type II functional responses. Temperature effects on predator-prey dynamics were, however, evident as interaction strength was greatest at 21 °C, as measured by maximum feeding rates. Unlike maximum feeding rate, attack rates increased linearly with increasing temperature across the experimental treatments. Our findings suggest that interaction strength between the mysid shrimp species is likely to vary spatially along the current length of their sympatric distribution and temporally in certain regions where temperatures are projected to change. Such experimental interaction investigations are becoming increasingly important given our relatively poor understanding of the consequences of environmental change for effects on interactions among species and their wider ecosystem implications.
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Affiliation(s)
- Ryan J Wasserman
- Department of Biological Sciences and Biotechnology, Botswana International University of Science and Technology, P. Bag 16, Palapye, Botswana; South African Institute for Aquatic Biodiversity (SAIAB), P. Bag 1015, Grahamstown, 6140, South Africa.
| | - Ross N Cuthbert
- Institute for Global Food Security, School of Biological Sciences, Queen's University Belfast, Belfast, BT9 7BL, Northern Ireland, United Kingdom
| | - Mhairi E Alexander
- Institute for Biomedical and Environmental Health Research, School of Science and Sport, University of the West of Scotland, Paisley, Scotland, United Kingdom
| | - Tatenda Dalu
- Department of Ecology and Resource Management, University of Venda, Thohoyandou, 0950, South Africa
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3
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Elliott KH, Betini GS, Norris DR. Fear creates an Allee effect: experimental evidence from seasonal populations. Proc Biol Sci 2017; 284:rspb.2017.0878. [PMID: 28659452 DOI: 10.1098/rspb.2017.0878] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2017] [Accepted: 05/26/2017] [Indexed: 11/12/2022] Open
Abstract
Allee effects driven by predation can play a strong role in the decline of small populations but are conventionally thought to occur when generalist predators target specific prey (i.e. type II functional response). However, aside from direct consumption, fear of predators could also increase vigilance and reduce time spent foraging as population size decreases, as has been observed in wild mammals living in social groups. To investigate the role of fear on fitness in relation to population density in a species with limited sociality, we exposed varying densities of Drosophila melanogaster to mantid predators either during an experimental breeding season or non-breeding season. The presence of mantids in either season decreased the reproductive performance of individuals but only at low breeding densities, providing evidence for an Allee effect. We then used our experimental results to parametrize a mathematical model to examine the population consequences of fear at low densities. Fear tended to destabilize population dynamics and increase the risk of extinction up to sevenfold. Our study provides unique experimental evidence that the indirect effects of the presence of predators can cause an Allee effect and has important consequences for our understanding of the dynamics of small populations.
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Affiliation(s)
- Kyle H Elliott
- Department of Integrative Biology, University of Guelph, Guelph, Ontario, Canada N1G 2W1 .,Department of Natural Resource Sciences, McGill University, Ste Anne-de-Bellevue, Quebec, Canada H9X 3V9
| | - Gustavo S Betini
- Department of Integrative Biology, University of Guelph, Guelph, Ontario, Canada N1G 2W1
| | - D Ryan Norris
- Department of Integrative Biology, University of Guelph, Guelph, Ontario, Canada N1G 2W1
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4
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Jackson M, Wasserman R, Grey J, Ricciardi A, Dick J, Alexander M. Novel and Disrupted Trophic Links Following Invasion in Freshwater Ecosystems. ADV ECOL RES 2017. [DOI: 10.1016/bs.aecr.2016.10.006] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
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5
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Wasserman RJ, Alexander ME, Weyl OLF, Barrios-O'Neill D, Froneman PW, Dalu T. Emergent effects of structural complexity and temperature on predator-prey interactions. Ecosphere 2016. [DOI: 10.1002/ecs2.1239] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Affiliation(s)
- Ryan J. Wasserman
- South African Institute for Aquatic Biodiversity (SAIAB); Private Bag 1015 Grahamstown 6140 South Africa
- Centre for Invasion Biology; South African Institute for Aquatic Biodiversity (SAIAB); Private Bag 1015 Grahamstown 6140 South Africa
| | - Mhairi E. Alexander
- Department of Botany and Zoology; Centre for Invasion Biology; Stellenbosch University; Matieland 7602 South Africa
| | - Olaf L. F. Weyl
- South African Institute for Aquatic Biodiversity (SAIAB); Private Bag 1015 Grahamstown 6140 South Africa
- Centre for Invasion Biology; South African Institute for Aquatic Biodiversity (SAIAB); Private Bag 1015 Grahamstown 6140 South Africa
| | - Daniel Barrios-O'Neill
- Institute for Global Food Security; School of Biological Sciences; Queens University Belfast; 97 Lisburn Road Belfast BT9 7BL UK
| | - P. William Froneman
- Department of Zoology and Entomology; Rhodes University; P.O. Box 94 Grahamstown 6140 South Africa
| | - Tatenda Dalu
- Department of Zoology and Entomology; Rhodes University; P.O. Box 94 Grahamstown 6140 South Africa
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Dick JTA, Alexander ME, Jeschke JM, Ricciardi A, MacIsaac HJ, Robinson TB, Kumschick S, Weyl OLF, Dunn AM, Hatcher MJ, Paterson RA, Farnsworth KD, Richardson DM. Advancing impact prediction and hypothesis testing in invasion ecology using a comparative functional response approach. Biol Invasions 2013. [DOI: 10.1007/s10530-013-0550-8] [Citation(s) in RCA: 184] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Abstract
Invasion ecology urgently requires predictive methodologies that can forecast the ecological impacts of existing, emerging and potential invasive species. We argue that many ecologically damaging invaders are characterised by their more efficient use of resources. Consequently, comparison of the classical ‘functional response’ (relationship between resource use and availability) between invasive and trophically analogous native species may allow prediction of invader ecological impact. We review the utility of species trait comparisons and the history and context of the use of functional responses in invasion ecology, then present our framework for the use of comparative functional responses. We show that functional response analyses, by describing the resource use of species over a range of resource availabilities, avoids many pitfalls of ‘snapshot’ assessments of resource use. Our framework demonstrates how comparisons of invader and native functional responses, within and between Type II and III functional responses, allow testing of the likely population-level outcomes of invasions for affected species. Furthermore, we describe how recent studies support the predictive capacity of this method; for example, the invasive ‘bloody red shrimp’ Hemimysis anomala shows higher Type II functional responses than native mysids and this corroborates, and could have predicted, actual invader impacts in the field. The comparative functional response method can also be used to examine differences in the impact of two or more invaders, two or more populations of the same invader, and the abiotic (e.g. temperature) and biotic (e.g. parasitism) context-dependencies of invader impacts. Our framework may also address the previous lack of rigour in testing major hypotheses in invasion ecology, such as the ‘enemy release’ and ‘biotic resistance’ hypotheses, as our approach explicitly considers demographic consequences for impacted resources, such as native and invasive prey species. We also identify potential challenges in the application of comparative functional responses in invasion ecology. These include incorporation of numerical responses, multiple predator effects and trait-mediated indirect interactions, replacement versus non-replacement study designs and the inclusion of functional responses in risk assessment frameworks. In future, the generation of sufficient case studies for a meta-analysis could test the overall hypothesis that comparative functional responses can indeed predict invasive species impacts.
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Alexander ME, Dick JTA, O’Connor NE. Trait-mediated indirect interactions in a marine intertidal system as quantified by functional responses. OIKOS 2013. [DOI: 10.1111/j.1600-0706.2013.00472.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Ward DM, Nislow KH, Folt CL. Seasonal shift in the effect of predators on juvenile Atlantic salmon ( Salmo salar) energetics. CANADIAN JOURNAL OF FISHERIES AND AQUATIC SCIENCES. JOURNAL CANADIEN DES SCIENCES HALIEUTIQUES ET AQUATIQUES 2011; 68:2080-2089. [PMID: 27812237 PMCID: PMC5089841 DOI: 10.1139/f2011-123] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Predator effects on prey populations are determined by the number of prey consumed and effects on the traits of surviving prey. Yet, effects of predators on prey traits are rarely evaluated in field studies. We measured the effects of predators on energetic traits (consumption and growth rates) of juvenile Atlantic salmon (Salmo salar) in a large-scale field study. Salmon fry were released at 18 sites that encompassed a wide range in abundance of predatory slimy sculpin (Cottus cognatus). We sampled salmon after 21 and 140 days to measure salmon growth and estimate consumption using a mass-balance model of methylmercury accumulation. Salmon population density was reduced fivefold at sites with abundant sculpin. Over the early season, salmon consumed less where sculpin were abundant, suggesting that reduced foraging under predation risk contributed to predator-caused mortality. In contrast, over the late season, salmon grew more where sculpin were abundant, suggesting that compensatory growth at reduced salmon population density moderated predator-caused mortality. Predator effects on prey energetics can drive variation in survival and growth, with important consequences for population dynamics.
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Affiliation(s)
- Darren M. Ward
- Department of Biological Sciences, Dartmouth College, Hanover, NH 03755, USA
| | - Keith H. Nislow
- Northern Research Station, USDA-USFS, University of Massachusetts, Amherst, MA 01003, USA
| | - Carol L. Folt
- Department of Biological Sciences, Dartmouth College, Hanover, NH 03755, USA
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Einum S, Finstad AG, Robertsen G, Nislow KH, McKelvey S, Armstrong JD. Natal movement in juvenile Atlantic salmon: a body size-dependent strategy? POPUL ECOL 2011. [DOI: 10.1007/s10144-011-0296-z] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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10
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Otero J, Jensen AJ, L'Abée-Lund JH, Stenseth NC, Storvik GO, Vøllestad LA. Quantifying the ocean, freshwater and human effects on year-to-year variability of one-sea-winter Atlantic salmon angled in multiple Norwegian rivers. PLoS One 2011; 6:e24005. [PMID: 21897867 PMCID: PMC3163678 DOI: 10.1371/journal.pone.0024005] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2011] [Accepted: 08/02/2011] [Indexed: 11/18/2022] Open
Abstract
Many Atlantic salmon, Salmo salar, populations are decreasing throughout the species' distributional range probably due to several factors acting in concert. A number of studies have documented the influence of freshwater and ocean conditions, climate variability and human impacts resulting from impoundment and aquaculture. However, most previous research has focused on analyzing single or only a few populations, and quantified isolated effects rather than handling multiple factors in conjunction. By using a multi-river mixed-effects model we estimated the effects of oceanic and river conditions, as well as human impacts, on year-to-year and between-river variability across 60 time series of recreational catch of one-sea-winter salmon (grilse) from Norwegian rivers over 29 years (1979-2007). Warm coastal temperatures at the time of smolt entrance into the sea and increased water discharge during upstream migration of mature fish were associated with higher rod catches of grilse. When hydropower stations were present in the course of the river systems the strength of the relationship with runoff was reduced. Catches of grilse in the river increased significantly following the reduction of the harvesting of this life-stage at sea. However, an average decreasing temporal trend was still detected and appeared to be stronger in the presence of salmon farms on the migration route of smolts in coastal/fjord areas. These results suggest that both ocean and freshwater conditions in conjunction with various human impacts contribute to shape interannual fluctuations and between-river variability of wild Atlantic salmon in Norwegian rivers. Current global change altering coastal temperature and water flow patterns might have implications for future grilse catches, moreover, positioning of aquaculture facilities as well as the implementation of hydropower schemes or other encroachments should be made with care when implementing management actions and searching for solutions to conserve this species.
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Affiliation(s)
- Jaime Otero
- Department of Biology, Centre for Ecological and Evolutionary Synthesis, University of Oslo, Oslo, Norway.
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Letcher BH, Coombs JA, Nislow KH. Maintenance of phenotypic variation: repeatability, heritability and size-dependent processes in a wild brook trout population. Evol Appl 2011; 4:602-15. [PMID: 25568008 PMCID: PMC3352425 DOI: 10.1111/j.1752-4571.2011.00184.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2010] [Accepted: 01/26/2011] [Indexed: 11/27/2022] Open
Abstract
Phenotypic variation in body size can result from within-cohort variation in birth dates, among-individual growth variation and size-selective processes. We explore the relative effects of these processes on the maintenance of wide observed body size variation in stream-dwelling brook trout (Salvelinus fontinalis). Based on the analyses of multiple recaptures of individual fish, it appears that size distributions are largely determined by the maintenance of early size variation. We found no evidence for size-dependent compensatory growth (which would reduce size variation) and found no indication that size-dependent survival substantially influenced body size distributions. Depensatory growth (faster growth by larger individuals) reinforced early size variation, but was relatively strong only during the first sampling interval (age-0, fall). Maternal decisions on the timing and location of spawning could have a major influence on early, and as our results suggest, later (>age-0) size distributions. If this is the case, our estimates of heritability of body size (body length = 0.25) will be dominated by processes that generate and maintain early size differences. As a result, evolutionary responses to environmental change that are mediated by body size may be largely expressed via changes in the timing and location of reproduction.
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Affiliation(s)
- Benjamin H Letcher
- S.O. Conte Anadromous Fish Research Center, US Geological Survey/Leetown Science Center Turners Falls, MA, USA
| | - Jason A Coombs
- S.O. Conte Anadromous Fish Research Center, US Geological Survey/Leetown Science Center Turners Falls, MA, USA ; Program in Organismic and Evolutionary Biology, University of Massachusetts Amherst, MA, USA
| | - Keith H Nislow
- Northern Research Station, USDA Forest Service, University of Massachusetts Amherst, MA, USA
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12
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Ward DM, Nislow KH, Chen CY, Folt CL. Reduced trace element concentrations in fast-growing juvenile Atlantic salmon in natural streams. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2010; 44:3245-51. [PMID: 20356034 PMCID: PMC2861850 DOI: 10.1021/es902639a] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
To assess the effect of rapid individual growth on trace element concentrations in fish, we measured concentrations of seven trace elements (As, Cd, Cs, Hg, Pb, Se, Zn) in stream-dwelling Atlantic salmon (Salmo salar) from 15 sites encompassing a 10-fold range in salmon growth. All salmon were hatched under uniform conditions, released into streams, and sampled approximately 120 days later for trace element analysis. For most elements, element concentrations in salmon tracked those in their prey. Fast-growing salmon had lower concentrations of all elements than slow growers, after accounting for prey concentrations. This pattern held for essential and nonessential elements, as well as elements that accumulate from food and those that can accumulate from water. At the sites with the fastest salmon growth, trace element concentrations in salmon were 37% (Cs) to 86% (Pb) lower than at sites where growth was suppressed. Given that concentrations were generally below levels harmful to salmon and that the pattern was consistent across all elements, we suggest that dilution of elements in larger biomass led to lower concentrations in fast-growing fish. Streams that foster rapid, efficient fish growth may produce fish with lower concentrations of elements potentially toxic for human and wildlife consumers.
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Affiliation(s)
- Darren M Ward
- Department of Biological Sciences, Dartmouth College, Hanover, New Hampshire 03755, USA.
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Kramer AM, Drake JM. Experimental demonstration of population extinction due to a predator-driven Allee effect. J Anim Ecol 2010; 79:633-9. [PMID: 20102421 DOI: 10.1111/j.1365-2656.2009.01657.x] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
1. Allee effects may result in negative growth rates at low population density, with important implications for conservation and management of exploited populations. Theory predicts prey populations will exhibit Allee effects when their predator exhibits a Type II functional response, but empirical evidence linking this positively density-dependent variation in predator-induced individual mortality to population growth rate and probability of extinction is lacking. 2. Here, we report a demonstration of extinction due to predator-driven Allee effects in an experimental Daphnia-Chaoborus system. A component Allee effect caused by higher predation rates at low Daphnia density led to positive density dependence in per capita growth rate and accelerated extinction rate at low density. 3. A stochastic model of the process revealed how the critical density below which population growth is negative depends on the mechanistic details of the predator-prey interaction. 4. The ubiquity of predator-prey interactions and saturating functional responses suggests predator-driven Allee effects are potentially important in determining extinction risk of a large number of species.
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Affiliation(s)
- Andrew M Kramer
- Odum School of Ecology, University of Georgia, Athens, GA 30602, USA.
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Ward DM, Nislow KH, Chen CY, Folt CL. Rapid, efficient growth reduces mercury concentrations in stream-dwelling Atlantic salmon. TRANSACTIONS OF THE AMERICAN FISHERIES SOCIETY 2010; 139:1-10. [PMID: 20436784 PMCID: PMC2861578 DOI: 10.1577/t09-032.1] [Citation(s) in RCA: 98] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Mercury (Hg) is a potent toxin that biomagnifies in aquatic food webs. Large fish generally have higher Hg concentrations than small fish of the same species. However, models predict that fish that grow large faster should have lower Hg concentrations than small, slow-growing fish due to somatic growth dilution (SGD). We examined the relationship between Hg concentrations and growth rate in fish using a large-scale field experiment. Atlantic salmon (Salmo salar) fry hatched under uniform initial conditions were released at eighteen sites in natural streams, collected after one growing season, and Hg concentration and growth measured. As expected for Hg accumulation from food, mercury concentrations in salmon tracked Hg concentrations in their prey. Nonetheless, large, fast-growing salmon had lower Hg concentrations than small, slow-growing salmon, consistent with SGD. While prey Hg concentration accounted for 59% of the explained variation in salmon Hg concentration across sites, salmon growth rate accounted for 38% of the explained variation independent of prey Hg concentration. A mass-balance Hg accumulation model shows that such SGD occurs when fast growth is associated with high growth efficiency. Fish growth is tremendously variable and sensitive to anthropogenic impacts, so SGD of Hg has important implications for fisheries management.
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Affiliation(s)
- Darren M. Ward
- Department of Biological Sciences, Dartmouth College, Hanover, NH 03755, USA
| | - Keith H. Nislow
- Northern Research Station, USDA-USFS, University of Massachusetts, Amherst, MA 01003, USA
| | - Celia Y. Chen
- Department of Biological Sciences, Dartmouth College, Hanover, NH 03755, USA
| | - Carol L. Folt
- Department of Biological Sciences, Dartmouth College, Hanover, NH 03755, USA
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