Quantitative Assessment of Current Risks to Harlequin Ducks in Prince William Sound, Alaska, from the<i>Exxon Valdez</i>Oil Spill

Harwell, Mark A.; Gentile, John H.; Parker, Keith R.; Murphy, Stephen M.; Day, Robert H.; Bence, A. E.; Neff, Jerry M.; Wiens, John A.

doi:10.1080/10807039.2012.650582

Cited by 12 publications

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References 141 publications

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“…The estimated chronic no-observed-adverse-effects level for ingested TPAH in adult (550-660 g) male and female harlequin ducks is 2.00 and 2.14 mg TPAH/kg body weight/d, respectively [17]. Energetic needs of adult harlequin ducks range from approximately 1,300 kJ/d in summer to approximately 3,000 kJ/ d in winter, equivalent to approximately 155 g dry wt mussel tissue/d in winter [17].…”

Section: Pathway 1: the Water Columnmentioning

confidence: 99%

“…Because the objective of the current study is to assess the likelihood of exposure resulting from natural processes, not from human disturbance, we have excluded data from shoreline segment, KN-136A, in the Bay of Isles (site 23, Fig. 1), a peat bog that is not suitable foraging habitat for sea otters or harlequin ducks [16,17], because strong evidence exists of human disturbance from survey activities shortly before our survey teams visited this site in May or June of 2002, 2003, and 2004 [4,6].…”

Section: Data Sourcesmentioning

confidence: 99%

“…The geographic focus of this exposure evaluation is the NKI area, because many of its shores were heavily oiled in 1989, and a large number of studies of the fates and effects of the spilled oil have been performed in this area between 1989 and 2009. By environmentally significant amounts, we mean compositions and concentrations of and exposure durations to PAH that could harm wildlife, such as sea otters and harlequin ducks, that forage on the shore, as defined by risk-based concentrations of ingested individual and total PAH [16,17]. Polycyclic aromatic hydrocarbons are the chemicals of greatest toxicological concern in fresh and weathered petroleum [18,19] and represent approximately 1.2% by weight of the mass of organic matter in the unweathered North Slope (Alaska, USA), crude oil cargo of the Exxon Valdez [20].…”

Section: Introductionmentioning

confidence: 99%

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Exposure of sea otters and harlequin ducks in Prince William Sound, Alaska, USA, to shoreline oil residues 20 years after the Exxon Valdez oil spill

Neff¹,

Page

Boehm

2011

Enviro Toxic and Chemistry

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We assessed whether sea otters and harlequin ducks in an area of western Prince William Sound, Alaska, USA (PWS), oiled by the 1989 Exxon Valdez oil spill (EVOS), are exposed to polycyclic aromatic hydrocarbons (PAH) from oil residues 20 years after the spill. Spilled oil has persisted in PWS for two decades as surface oil residues (SOR) and subsurface oil residues (SSOR) on the shore. The rare SOR are located primarily on the upper shore as inert, nonhazardous asphaltic deposits, and SSOR are confined to widely scattered locations as small patches under a boulder/cobble veneer, primarily on the middle and upper shore, in forms and locations that preclude physical contact by wildlife and diminish bioavailability. Sea otters and harlequin ducks consume benthic invertebrates that they collect by diving to the bottom in the intertidal and subtidal zones. Sea otters also dig intertidal and subtidal pits in search of clams. The three plausible exposure pathways are through the water, in oil-contaminated prey, or by direct contact with SSOR during foraging. Concentrations of PAH in near-shore water off oiled shores in 2002 to 2005 were at background levels (<0.05 ng/L). Median concentrations of PAH in five intertidal prey species on oiled shores in 2002 to 2008 range from 4.0 to 34 ng/g dry weight, indistinguishable from background concentrations. Subsurface oil residues are restricted to locations on the shore and substrate types, where large clams do not occur and where sea otters do not dig foraging pits. Therefore, that sea otters and harlequin ducks continue to be exposed to environmentally significant amounts of PAH from EVOS 20 years after the spill is not plausible.

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Section: Pathway 1: the Water Columnmentioning

confidence: 99%

Section: Data Sourcesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Exposure of sea otters and harlequin ducks in Prince William Sound, Alaska, USA, to shoreline oil residues 20 years after the Exxon Valdez oil spill

Neff¹,

Page

Boehm

2011

Enviro Toxic and Chemistry

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“…Predictive modelling can fill this gap and individual-based models (IBMs; Grimm & Railsback, 2013;Sutherland, 1996) are widely used in many disciplines to model complex systems, for example, to predict the impacts of environmental change on shorebirds, seabirds and pinnipeds (Boyd et al, 2016a,b;Harwell et al, 2012;Langton, Davies, & Scott, 2014;McDonald, Searle, Wanless, & Daunt, 2012;Stillman et al, 2003;West & Caldow, 2006). They differ from conventional models by modelling autonomous entities, and each individual's behavioural and physiological traits determine the properties of the system, for example, taking into account individual variation and an individual's interaction with the environment (Grimm, 1999).…”

Section: Introductionmentioning

confidence: 99%

“…These installations may enhance the environment by creating de facto no fishing zones (Inger et al, 2009), but there is concern about the negative impacts they may have on Europe's breeding seabirds (Garthe & Hupop, 2004). These impacts may include direct mortality from (2016) conclude that the current methods to predict the impacts of offshore wind farms on seabirds are inadequate, and this demonstrates a demand to establish a robust methodology which can be used by planners to mitigate the impacts on seabirds, when identifying wind farm sites.Evidence-based decision making is the preferred approach when responding to such pressures (Solesbury, 2001), but may be challenging when there is little empirical evidence as to how systems will respond to environmental change (Botsford, Micheli, & Hastings, 2003).Predictive modelling can fill this gap and individual-based models (IBMs; Grimm & Railsback, 2013;Sutherland, 1996) are widely used in many disciplines to model complex systems, for example, to predict the impacts of environmental change on shorebirds, seabirds and pinnipeds (Boyd et al, 2016a,b;Harwell et al, 2012;Langton, Davies, & Scott, 2014;McDonald, Searle, Wanless, & Daunt, 2012;Stillman et al, 2003;West & Caldow, 2006). They differ from conventional models by modelling autonomous entities, and each individual's behavioural and physiological traits determine the properties of the system, for example, taking into account individual variation and an individual's interaction with the environment (Grimm, 1999).…”

mentioning

confidence: 99%

Predicting the impacts of wind farms on seabirds: An individual‐based model

Warwick-Evans

Atkinson

Walkington

et al. 2017

Journal of Applied Ecology

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Abstract1. Individual-based models (IBMs) are a powerful tool in predicting the consequences of environmental change on animal populations and supporting evidence-based decision making for conservation planning.2. There are increasing proposals for wind farms in UK waters and seabirds are a vulnerable group, which may be at risk from these developments.3. We developed a spatially explicit IBM to investigate the potential impacts of the installation of wind farms in the English Channel and North Sea on body mass, productivity and mortality of a breeding population of Northern gannets for which we have tracking data. A baseline model with no wind farms accurately represented the status of a sampleof tracked gannets at the end of the 90-day chick-rearing period, and the behaviourtime budget was similar to that of tracked gannets. Model simulations in the presence of wind farms indicated that installations shouldhave little impact on the gannet population, when either avoidance behaviour or collision risk scenarios were simulated. Furthermore, wind farms would need to be ten times larger or in more highly used areas in order to have population-level impacts on Alderney's gannets.6. Synthesis and applications. Our spatially explicit individual-based models (IBM) highlight that it is vital to know the colony-specific foraging grounds of seabirds that may be impacted, when identifying potential wind farm sites, in order to account for cumulative impacts from multiple sites. Avoiding areas highly used for foraging and commuting, and avoiding large-scale developments should be effective in limiting gannet mortality as a result of collision, competition and energy expenditure. Our IBM provides a robust approach which can be adapted for other seabird populations or to predict the impacts from other types of spatial change in the marine environment. K E Y W O R D Scollision risk, evidence-based decision making, individual based models, Morus bassanus, Northern gannets, offshore development, predictive modelling, seabirds, wind farmsThis is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. | Journal of Applied EcologyWARWICK-EVANS Et Al. | INTRODUCTIONThe marine environment is under increasing pressure from anthropogenic activities including overfishing, climate change and offshore developments such as wind farms (Halpern et al., 2012). These installations may enhance the environment by creating de facto no fishing zones (Inger et al., 2009), but there is concern about the negative impacts they may have on Europe's breeding seabirds (Garthe & Hupop, 2004). These impacts may include direct mortality from (2016) conclude that the current methods to predict the impacts of offshore wind farms on seabirds are inadequate, and this demonstrates a demand to establish a robust methodology which can be used by planners to mitigate the impacts on seabirds, when identifying wind farm sites.Evid...

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Quantifying population‐level risks using an individual‐based model: Sea otters, Harlequin Ducks, and the Exxon Valdez oil spill

Harwell¹,

Gentile

Parker

2012

Integr Envir Assess & Manag

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Ecological risk assessments need to advance beyond evaluating risks to individuals that are largely based on toxicity studies conducted on a few species under laboratory conditions, to assessing population-level risks to the environment, including considerations of variability and uncertainty. Two individual-based models (IBMs), recently developed to assess current risks to sea otters and seaducks in Prince William Sound more than 2 decades after the Exxon Valdez oil spill (EVOS), are used to explore population-level risks. In each case, the models had previously shown that there were essentially no remaining risks to individuals from polycyclic aromatic hydrocarbons (PAHs) derived from the EVOS. New sensitivity analyses are reported here in which hypothetical environmental exposures to PAHs were heuristically increased until assimilated doses reached toxicity reference values (TRVs) derived at the no-observed-adverse-effects and lowest-observed-adverse-effects levels (NOAEL and LOAEL, respectively). For the sea otters, this was accomplished by artificially increasing the number of sea otter pits that would intersect remaining patches of subsurface oil residues by orders of magnitude over actual estimated rates. Similarly, in the seaduck assessment, the PAH concentrations in the constituents of diet, sediments, and seawater were increased in proportion to their relative contributions to the assimilated doses by orders of magnitude over measured environmental concentrations, to reach the NOAEL and LOAEL thresholds. The stochastic IBMs simulated millions of individuals. From these outputs, frequency distributions were derived of assimilated doses for populations of 500 000 sea otters or seaducks in each of 7 or 8 classes, respectively. Doses to several selected quantiles were analyzed, ranging from the 1-in-1000th most-exposed individuals (99.9% quantile) to the median-exposed individuals (50% quantile). The resulting families of quantile curves provide the basis for characterizing the environmental thresholds below which no population-level effects could be detected and above which population-level effects would be expected to become manifest. This approach provides risk managers an enhanced understanding of the risks to populations under various conditions and assumptions, whether under hypothetically increased exposure regimes, as demonstrated here, or in situations in which actual exposures are near toxic effects levels. This study shows that individual-based models are especially amenable and appropriate for conducting population-level risk assessments, and that they can readily be used to answer questions about the risks to individuals and populations across a variety of exposure conditions. Integr Environ Assess Manag 2012; 8: 503–522. © 2012 SETAC

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Quantitative Assessment of Current Risks to Harlequin Ducks in Prince William Sound, Alaska, from theExxon ValdezOil Spill

Cited by 12 publications

References 141 publications

Exposure of sea otters and harlequin ducks in Prince William Sound, Alaska, USA, to shoreline oil residues 20 years after the Exxon Valdez oil spill

Exposure of sea otters and harlequin ducks in Prince William Sound, Alaska, USA, to shoreline oil residues 20 years after the Exxon Valdez oil spill

Predicting the impacts of wind farms on seabirds: An individual‐based model

Quantifying population‐level risks using an individual‐based model: Sea otters, Harlequin Ducks, and the Exxon Valdez oil spill

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