Article

Risks of ocean acidification in the California Current food web and fisheries: Ecosystem model projections

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Abstract

The benefits and ecosystem services that humans derive from the oceans are threatened by numerous global change stressors, one of which is ocean acidification. Here, we describe the effects of ocean acidification on an upwelling system that already experiences inherently low pH conditions, the California Current. We used an end-to-end ecosystem model (Atlantis), forced by downscaled global climate models and informed by a meta-analysis of the pH sensitivities of local taxa, to investigate the direct and indirect effects of future pH on biomass and fisheries revenues. Our model projects a 0.2-unit drop in pH during the summer upwelling season from 2013 to 2063, which results in wide-ranging magnitudes of effects across guilds and functional groups. The most dramatic direct effects of future pH may be expected on epibenthic invertebrates (crabs, shrimps, benthic grazers, benthic detritivores, bivalves), and strong indirect effects expected on some demersal fish, sharks, and epibenthic invertebrates (Dungeness crab) because they consume species known to be sensitive to changing pH. The model's pelagic community, including marine mammals and seabirds, was much less influenced by future pH. Some functional groups were less affected to changing pH in the model than might be expected from experimental studies in the empirical literature due to high population productivity (e.g., copepods, pteropods). Model results suggest strong effects of reduced pH on nearshore state-managed invertebrate fisheries, but modest effects on the groundfish fishery because individual groundfish species exhibited diverse responses to changing pH. Our results provide a set of projections that generally support and build upon previous findings and set the stage for hypotheses to guide future modeling and experimental analysis on the effects of OA on marine ecosystems and fisheries.

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... In order to enhance the use of salient science (Röckmann et al. 2015) into the policy-making process, proposes four steps: strategic goal setting; tactical objectives; management measures; and adaptive management. Integrated ecosystem assessments (IEAs) have also been proposed as a tool to operationalise EBM as they provide a framework for organizing science in order to inform decisions in marine EBM at multiple scales and across sectors (Levin et al. 2009a;Walther and Möllmann 2014;Tallis et al. 2010;Harvey et al. 2017). It is therefore not surprising that the IEA process described by (Levin et al. 2009b) is closely aligned to the EBM processes described by Börgstrom et al. (2015) or Ansong et al. (2017). ...
... Further to these conceptual approaches, a number of policy initiatives have sparked the development of a wide range of assessment frameworks and decision support systems for EBM (Harvey et al. 2017;Link and Browman 2017;Alexander and Haward 2019;). Yet, a major challenge remains as to the design of an operational framework that links, in an efficient way, the assessment of biodiversity and ecological processes and their meaningful consideration in decision-making processes (and not just in policy making), despite recent progress (Langhans et al. 2018;Do Yun et al. 2017). ...
... In whole-system (i.e., end-to-end) models (Travers et al. 2007), biophysical, socioeconomic, and industrial components and processes are considered, along with associated feedbacks and interactions between components Kaplan et al. 2012;Weijerman et al. 2015;Marshall et al. 2017). One such model is Atlantis, developed for use in Management Strategy Evaluation, it supports Ecosystem-Based Management (EBM) of multiple fisheries on a regional scale (Link et al. 2010;Fulton et al. 2011). ...
... Modeling efforts are being used to fill this gap by quantifying organism OA response curves [34] to parameterize ecosystem models. This has allowed researchers to identify ecosystem vulnerabilities in areas like the California Current [35], predict ecological change in the north Atlantic [36], and assess optimal management solutions [37]. However, a major drawback of these modeling efforts is the inclusion of only a single mechanism through which OA impacts model components, such as species production or mortality. ...
... Since Other Mortality is not directly included in the original EwE model, relative scaling of that parameter was not an option. Instead, methods developed in Marshall et al. (2017) were applied to quantify Other Mortality. The relationships developed in Busch and McElhany (2016) [34] were created with the goal of incorporating them into an Atlantis model of the CC, which was published in Marshall et al. (2017). ...
... Instead, methods developed in Marshall et al. (2017) were applied to quantify Other Mortality. The relationships developed in Busch and McElhany (2016) [34] were created with the goal of incorporating them into an Atlantis model of the CC, which was published in Marshall et al. (2017). In that study, direct mortality effects were calculated as ...
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... The greatest impacts were predicted to be on the demersal food web, with fshing impacting predation and acidifcation affecting benthic production, but ultimately also an overall restructuring of both pelagic and demersal food webs as a result (Bascompte et al. 2005;Griffth et al. 2011). Other studies modeling the effects of decreases in pH related to ocean acidifcation (e.g., 0.2-unit drop in pH) found wide-ranging magnitudes of effects, with the most dramatic direct effects being found on epibenthic invertebrates (e.g., crabs, shrimps, benthic grazers, benthic detritivores, bivalves) and strong indirect 782 Biology of Sharks and Their Relatives effects on demersal fshes, including sharks, and epibenthic invertebrates (e.g., dungeness crab, Metacarcinus magister), likely because they consume pH-sensitive species (Marshall et al. 2017). Indeed, the presence and direction of change vary across models, study regions, and factors at play (Brown et al. 2010;Griffth et al. 2011;Marshall et al. 2017). ...
... Other studies modeling the effects of decreases in pH related to ocean acidifcation (e.g., 0.2-unit drop in pH) found wide-ranging magnitudes of effects, with the most dramatic direct effects being found on epibenthic invertebrates (e.g., crabs, shrimps, benthic grazers, benthic detritivores, bivalves) and strong indirect 782 Biology of Sharks and Their Relatives effects on demersal fshes, including sharks, and epibenthic invertebrates (e.g., dungeness crab, Metacarcinus magister), likely because they consume pH-sensitive species (Marshall et al. 2017). Indeed, the presence and direction of change vary across models, study regions, and factors at play (Brown et al. 2010;Griffth et al. 2011;Marshall et al. 2017). ...
... Under the proposed framework, 30 of the 133 species evaluated were categorized as "Vulnerable." Species associated with freshwater or estuaries, along with coastal and reef systems, rank higher with respect to climate change risk; however, acknowledging the challenges associated with quantifying large-scale impacts of each driver, current advances in the literature suggest that the effects of ocean acidifcation may have been underestimated (Marshall et al. 2017;Rosa et al. 2017). Moreover, deoxygenation, in the form of either long-term O 2 depletion or an increase in hypoxic events, was not included as a stress driver, despite its potential to greatly impact biological responses (Sampaio et al. 2021). ...
... The California Current Atlantis model has been described in depth Marshall et al., 2017). Briefly, the model includes five primary producer groups, 25 benthic and planktonic invertebrates, 36 fish groups, 10 marine mammal groups, three bird groups, and two detritus categories. ...
... Peterson, unpublished data, NOAA NWFSC, Newport Oregon). The model is forced by Regional Ocean Modeling System (ROMS) output for 2013, as in Marshall et al. (2017). This oceanography drives Atlantis daily temperature, salinity, and currents; in the present application we do not apply the values of pH from Marshall et al. (2017) to the biological response of the model. ...
... The model is forced by Regional Ocean Modeling System (ROMS) output for 2013, as in Marshall et al. (2017). This oceanography drives Atlantis daily temperature, salinity, and currents; in the present application we do not apply the values of pH from Marshall et al. (2017) to the biological response of the model. The California Current model generally does not require a spin-up, and after initialization in year 2013 reaches quasi-stable behavior (under constant fishing) by approximately year 30, before our results reporting years 41-50. ...
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... In whole-system (i.e., end-to-end) models (Travers et al. 2007), biophysical, socioeconomic, and industrial components and processes are considered, along with associated feedbacks and interactions between components Kaplan et al. 2012;Weijerman et al. 2015;Marshall et al. 2017). One such model is Atlantis, developed for use in Management Strategy Evaluation, it supports Ecosystem-Based Management (EBM) of multiple fisheries on a regional scale (Link et al. 2010;Fulton et al. 2011). ...
... One such model is Atlantis, developed for use in Management Strategy Evaluation, it supports Ecosystem-Based Management (EBM) of multiple fisheries on a regional scale (Link et al. 2010;Fulton et al. 2011). Atlantis is a complex, spatially explicit, hierarchical model containing interconnected submodels to evaluate potential management actions, policy changes, and ecosystem tradeoffs under various scenarios (Kaplan et al. 2012;Fulton et al. 2014;Marshall et al. 2017). ...
... Endpoints of Atlantis can include metrics such as biomass, concentration, catch, effort, or revenue (Link et al. 2010;Fulton et al. 2011;Kaplan et al. 2012;Marshall et al. 2017). Marshall et al. (2017) built upon previous applications (Kaplan et al. 2012;Weijerman et al. 2015) and utilized Atlantis to project the impacts of ocean acidification scenarios on fisheries EGS in the California Current ecosystem. ...
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... McKibben et al. [51]; Marshall et al. [52]; Bauer et al. [53] Modify existing prioritization tools and status updates (e.g., ecological risk assessment, productivity-susceptibility analyses, integrated ecosystem assessments) to include climate information. ...
... In addition, understanding biophysical and ecosystem impacts is even more valuable to managers when directly linked to economics. To this end, Marshall et al. [52] demonstrates the linkages between predicted ocean acidification impacts on economics of fisheries, allowing decision-makers and stakeholders to visualize potential changes to local economies. ...
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... Indeed, a meta-analysis of multiple stressor studies found that simple additive interactions occur in only 26% of studies, with synergistic (amplified effects) and antagonistic (dampened effects) interactions occurring in 36 and 38% of studies, respectively 8 . However, direct experimental quantification of stressor effects on organisms and ecosystems is limited to individual stressors and a few pairwise interactions 8,[13][14][15] . There is an urgent need to analyze how suites of multiple co-occurring stressors impact entire food webs in order to anticipate possible tipping points and focus management interventions on the most deleterious stressor combinations [16][17][18][19] . ...
... Existing models provide relatively fine-scale predictions of how individual stressors affect whole ecosystems 15 . However, synergistic interactions between stressors can yield non-linear impacts 11 that when unaccounted for may underestimate risk to organisms. ...
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... The trophic and spatial complexity of these models means that they differ in assumptions from commonly used stock assessment methods, thus providing an alternative test of estimation models and management strategies. Ecological models often include alternate scenarios for climate, oceanography, and ecological relationships (e.g., Punt et al., 2016b;Marshall et al., 2017;Woodworth-Jefcoats et al., 2019), which can bound the uncertainty around operating model dynamics within the MSE simulation testing (Link et al., , 2012. ...
... For the California Current and Nordic/Barents Seas, a project is underway to simulation test estimation models using Atlantis ecosystem operating models; these estimation models mimic those used in real-world stock assessments. Ecosystem models for the California Current off the United States West Coast Marshall et al., 2017) and Nordic and Barents Seas off Norway (Hansen et al., 2016(Hansen et al., , 2019a have been forced with climate scenarios that include ocean acidification and warming ocean temperature. These ecosystem models are spatially explicit and include biological groups ranging from primary producers to top predators. ...
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Management strategy evaluation (MSE) is a simulation approach that serves as a “light on the hill” ( Smith, 1994 ) to test options for marine management, monitoring, and assessment against simulated ecosystem and fishery dynamics, including uncertainty in ecological and fishery processes and observations. MSE has become a key method to evaluate trade-offs between management objectives and to communicate with decision makers. Here we describe how and why MSE is continuing to grow from a single species approach to one relevant to multi-species and ecosystem-based management. In particular, different ecosystem modeling approaches can fit within the MSE process to meet particular natural resource management needs. We present four case studies that illustrate how MSE is expanding to include ecosystem considerations and ecosystem models as ‘operating models’ (i.e., virtual test worlds), to simulate monitoring, assessment, and harvest control rules, and to evaluate tradeoffs via performance metrics. We highlight United States case studies related to fisheries regulations and climate, which support NOAA’s policy goals related to the Ecosystem Based Fishery Roadmap and Climate Science Strategy but vary in the complexity of population, ecosystem, and assessment representation. We emphasize methods, tool development, and lessons learned that are relevant beyond the United States, and the additional benefits relative to single-species MSE approaches.
... Thirty-eight studies performed hindcast runs (Pilcher et al., 2018) and six studies ran future simulations for over a thousand years . Marshall et al. (2017) ran simulations for 100 years, but looped a single year ROMS oceanography 100 times. This was done to reduce the computational cost, control inter-annual variability of oceanic conditions and isolate the impacts of distinct drivers of change. ...
... Six studies considered effects of changes in pCO 2 as ocean acidification effects on marine biota. They predict declines in primary production (Yool et al., 2013), fish and invertebrates growth (Cornwall and Eddy, 2015), the biomass of low pH sensitive benthic biota and the abundance of demersal fish, sharks and epibenthic invertebrates that feed on these benthic biota (Marshall et al., 2017;Fay et al., 2017). Van Oostende et al. (2018) project a shift to a pelagicoriented marine ecosystem. ...
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... Thirty-eight studies performed hindcast runs (Pilcher et al., 2018) and six studies ran future simulations for over a thousand years . Marshall et al. (2017) ran simulations for 100 years, but looped a single year ROMS oceanography 100 times. This was done to reduce the computational cost, control inter-annual variability of oceanic conditions and isolate the impacts of distinct drivers of change. ...
... Six studies considered effects of changes in pCO 2 as ocean acidification effects on marine biota. They predict declines in primary production (Yool et al., 2013), fish and invertebrates growth (Cornwall and Eddy, 2015), the biomass of low pH sensitive benthic biota and the abundance of demersal fish, sharks and epibenthic invertebrates that feed on these benthic biota (Marshall et al., 2017;Fay et al., 2017). Van Oostende et al. (2018) project a shift to a pelagicoriented marine ecosystem. ...
... By 2063, a decline of 0.2 units in pH is expected during the summer upwelling season in the California Current. Using the end-to-end ecosystem model Atlantis, Marshall et al. (2017) projected dramatic effects for epibenthic invertebrates, including economically and ecologically important species (e.g., crabs and shrimp) and some demersal fish due to both direct and indirect mechanisms. Pteropods are already near an ecological threshold and may be among the first species facing extirpation due to acidification (Bednarsek et al. 2017). ...
... Additional declines in DO may further effect the CCE upwelling system due to previously described current connections in the North Pacific Gyre system (Pozo Buil and Di Lorenzo 2017). Marshall et al. (2017) utilized an ecosystem model (Atlantis), forced by downscaled climate models and informed by species-specific pH sensitivities, to investigate the effects of ocean acidification on the CCE ecosystem and dependent fisheries. They predicted the pH would decline by 0.2 units from 2013 to 2063. ...
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Impacts of Climate Change on Salmon of the Pacific Northwest A review of the scientific literature published in 2017
... These direct effects may manifest themselves within specific populations through increasing or decreasing growth, reproduction, and mortality (Pörtner, 2012); changes in geographic distribution as populations shift toward more favorable habitat; or shifts in the phenological timing of environmentally influenced events such as phytoplankton blooms (Karp et al., 2019). Food web interactions further complicate the potential influence of even small changes within one population Fay et al., 2017;Marshall et al., 2017;Masi et al., 2018). ...
... The integration of these environmental and ecological processes has become an explicit aim of regional ecosystembased fisheries management (EBFM) frameworks (Marshall et al., 2017;Holsman et al., 2020), and global Earth system models (ESMs) offer an enticing tool to the regional fisheries scientist to potentially quantify these many impacts of environmental change on LMRs. The representation of the biosphere within these coupled models has expanded rapidly over the past several iterations of the Intergovernmental Panel of Climate Change (IPCC) assessment reports. ...
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Climate change may impact ocean ecosystems through a number of mechanisms, including shifts in primary productivity or plankton community structure, ocean acidification, and deoxygenation. These processes can be simulated with global Earth system models (ESMs), which are increasingly being used in the context of fisheries management and other living marine resource (LMR) applications. However, projections of LMR-relevant metrics such as net primary production can vary widely between ESMs, even under identical climate scenarios. Therefore, the use of ESM should be accompanied by an understanding of the structural differences in the biogeochemical sub-models within ESMs that may give rise to these differences. This review article provides a brief overview of some of the most prominent differences among the most recent generation of ESM and how they are relevant to LMR application.
... Concurrently, the average Ω A and pH in the top 60 m of the CCS water column decreased by ∼0.1 and 0.02 per decade, respectively (Osborne et al., 2020;Turi et al., 2016). OA has been suggested to threaten the highly productive California current ecosystem and its associated blue economy (Cooley & Doney, 2009;Ekstrom et al., 2015;Marshall et al., 2017), with many native taxa under pressure (Busch & McElhany, 2016). For instance, in the pelagic realm, the negative effect of OA on pteropods, an abundant group in the top 100 m of the CCS waters and important element of the CCS food web (Bednaršek et al., 2012(Bednaršek et al., , 2014Bednaršek & Ohman, 2015), may have cascading repercussions on higher trophic levels (Haigh et al., 2015;Marshall et al., 2017). ...
... OA has been suggested to threaten the highly productive California current ecosystem and its associated blue economy (Cooley & Doney, 2009;Ekstrom et al., 2015;Marshall et al., 2017), with many native taxa under pressure (Busch & McElhany, 2016). For instance, in the pelagic realm, the negative effect of OA on pteropods, an abundant group in the top 100 m of the CCS waters and important element of the CCS food web (Bednaršek et al., 2012(Bednaršek et al., , 2014Bednaršek & Ohman, 2015), may have cascading repercussions on higher trophic levels (Haigh et al., 2015;Marshall et al., 2017). ...
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Ocean acidification is punctuated by episodic extremes of low pH and saturation state with regard to aragonite (ΩA). Here, we use a hindcast simulation from 1984 to 2019 with a high‐resolution regional ocean model (ROMS‐BEC) to identify and track ocean acidification extremes (OAX) in the northeast Pacific and the California current system (CCS). In the first step, we identify all grid‐cells whose pH and ΩA are simultaneously below their first percentile over the analysis period (1984–2019). In the second step, we aggregate all neighboring cells with extreme conditions into three‐dimensional time evolving events, permitting us to track them in a Lagrangian manner over their lifetime. We detect more than 22 thousand events that occur at least once in the upper 100 m during their lifetime, with broad distributions in terms of size, duration, volume, and intensity, and with 26% of them harboring corrosive conditions (ΩA < 1). By clustering the OAXs, we find three types of extremes in the CCS. Near the coast, intense, shallow, and short‐lasting OAXs dominate, caused by strong upwelling. A second type consists of large and long‐lasting OAX events that are associated with westward propagating cyclonic eddies. They account for only 3% of all extremes, but are the most severe events. The third type is small extremes at depth arising from pycnocline heave. OAXs potentially have deleterious effects on marine life. Marine calcifiers, such as pteropods, might be especially impacted by the long‐lasting events with corrosive conditions.
... These changes are referred to as ocean acidification (OA) (Caldeira and Wickett, 2003;Doney et al., 2009;Le Quéré et al., 2018). Information from the geological record (Hönisch et al., 2012), laboratory experiments (Kroeker et al., 2013), field observations (Keller et al., 2014;Sutton et al., 2016Sutton et al., , 2017Henson et al., 2017;Turk et al., 2019), and numerical modelling (Marshall et al., 2017) strongly suggests that OA has the potential to alter the function of ocean ecosystems, impacting marine biota and ecosystem services (Andersson et al., 2015). However, characterizing current and future effects of OA on marine systems is challenging. ...
... (4) Characterize ecosystem trajectories through long-term monitoring: understanding how and why species are sensitive to OA has vastly improved, but this is just one aspect of understanding population and ecosystem responses in situ. For example, a species' population dynamics may be influenced more by OAinduced modifications of ecological interactions than by direct sensitivity (Marshall et al., 2017). In some instances, ecological interactions have been hypothesized to mitigate OA impacts through enhancing adaptive capacity or mitigating the effects of elevated CO 2 conditions (Kapsenberg and Cyronak, 2019). ...
Article
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A substantial body of research now exists demonstrating sensitivities of marine organisms to ocean acidification (OA) in laboratory settings. However, corresponding in situ observations of marine species or ecosystem changes that can be unequivocally attributed to anthropogenic OA are limited. Challenges remain in detecting and attributing OA effects in nature, in part because multiple environmental changes are co-occurring with OA, all of which have the potential to influence marine ecosystem responses. Furthermore, the change in ocean pH since the industrial revolution is small relative to the natural variability within many systems, making it difficult to detect, and in some cases, has yet to cross physiological thresholds. The small number of studies that clearly document OA impacts in nature cannot be interpreted as a lack of larger-scale attributable impacts at the present time or in the future but highlights the need for innovative research approaches and analyses. We summarize the general findings in four relatively well-studied marine groups (seagrasses, pteropods, oysters, and coral reefs) and integrate overarching themes to highlight the challenges involved in detecting and attributing the effects of OA in natural environments. We then discuss four potential strategies to better evaluate and attribute OA impacts on species and ecosystems. First, we highlight the need for work quantifying the anthropogenic input of CO 2 in coastal and open-ocean waters to understand how this increase in CO 2 interacts with other physical and chemical factors to drive organismal conditions. Second, understanding OA-induced changes in population-level demography, potentially increased sensitivities in certain life stages, and how these effects scale to ecosystem-level processes (e.g. community metabolism) will improve our ability to attribute impacts to OA among co-varying parameters. Third, there is a great need to understand the potential modulation of OA impacts through the interplay of ecology and evolution (eco-evo dynamics). Lastly, further research efforts designed to detect , quantify, and project the effects of OA on marine organisms and ecosystems utilizing a comparative approach with long-term data sets will also provide critical information for informing the management of marine ecosystems.
... These changes are referred to as ocean acidification (OA) (Caldeira and Wickett, 2003;Doney et al., 2009;Le Quéré et al., 2018). Information from the geological record (Hönisch et al., 2012), laboratory experiments (Kroeker et al., 2013), field observations (Keller et al., 2014;Sutton et al., 2016Sutton et al., , 2017Henson et al., 2017;Turk et al., 2019), and numerical modelling (Marshall et al., 2017) strongly suggests that OA has the potential to alter the function of ocean ecosystems, impacting marine biota and ecosystem services (Andersson et al., 2015). However, characterizing current and future effects of OA on marine systems is challenging. ...
... (4) Characterize ecosystem trajectories through long-term monitoring: understanding how and why species are sensitive to OA has vastly improved, but this is just one aspect of understanding population and ecosystem responses in situ. For example, a species' population dynamics may be influenced more by OAinduced modifications of ecological interactions than by direct sensitivity (Marshall et al., 2017). In some instances, ecological interactions have been hypothesized to mitigate OA impacts through enhancing adaptive capacity or mitigating the effects of elevated CO 2 conditions (Kapsenberg and Cyronak, 2019). ...
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A substantial body of research now exists demonstrating sensitivities of marine organisms to ocean acidification (OA) in laboratory settings. However, corresponding in situ observations of marine species or ecosystem changes that can be unequivocally attributed to anthropogenic OA are limited. Challenges remain in detecting and attributing OA effects in nature, in part because multiple environmental changes are co-occurring with OA, all of which have the potential to influence marine ecosystem responses. Furthermore, the change in ocean pH since the industrial revolution is small relative to the natural variability within many systems, making it difficult to detect, and in some cases, has yet to cross physiological thresholds. The small number of studies that clearly document OA impacts in nature cannot be interpreted as a lack of larger-scale attributable impacts at the present time or in the future but highlights the need for innovative research approaches and analyses. We summarize the general findings in four relatively well-studied marine groups (seagrasses, pteropods, oysters, and coral reefs) and integrate overarching themes to highlight the challenges involved in detecting and attributing the effects of OA in natural environments. We then discuss four potential strategies to better evaluate and attribute OA impacts on species and ecosystems. First, we highlight the need for work quantifying the anthropogenic input of CO2 in coastal and open-ocean waters to understand how this increase in CO2 interacts with other physical and chemical factors to drive organismal conditions. Second, understanding OA-induced changes in population-level demography, potentially increased sensitivities in certain life stages, and how these effects scale to ecosystem-level processes (e.g. community metabolism) will improve our ability to attribute impacts to OA among co-varying parameters. Third, there is a great need to understand the potential modulation of OA impacts through the interplay of ecology and evolution (eco–evo dynamics). Lastly, further research efforts designed to detect, quantify, and project the effects of OA on marine organisms and ecosystems utilizing a comparative approach with long-term data sets will also provide critical information for informing the management of marine ecosystems.
... A full scale end-to-end examination using the Atlantis model explored the impact of ocean acidification on the California Current ecosystem (Marshall et al. 2017). Species groups that showed direct negative effects of OA, such as epibenthic invertebrates (crabs, shrimps, benthic grazers, benthic detritivores, bivalves) experienced the largest declines. ...
... End-to-end models attempt to mechanistically link atmospheric and physical drivers through ocean ecosystem processes all the way to top predators and fisheries. End-to-end models for the California Current explored how different upwelling scenarios affected productivity (Ruzicka et al. 2016a), how environmental variability affected sea lion foraging ecology (Fiechter et al. 2016), and how ocean acidification changed fisheries revenue (Marshall et al. 2017). Ruzicka et al. (2016a) described results from an end-to-end model of the Northern California Current Ecosystem. ...
... Finally, our model is conservative in that we have not accounted for any negative effects of ocean acidification. Declines of sensitive species could have a negative effect on salmon, especially salmon populations that rely more heavily on sensitive species 67 . We have assumed that ocean-stage salmon are relatively insensitive to pH, but if there are effects from ocean acidification, they will likely be negative 68,69 . ...
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Widespread declines in Atlantic and Pacific salmon (Salmo salar and Oncorhynchus spp.) have tracked recent climate changes, but managers still lack quantitative projections of the viability of any individual population in response to future climate change. To address this gap, we assembled a vast database of survival and other data for eight wild populations of threatened Chinook salmon (O. tshawytscha). For each population, we evaluated climate impacts at all life stages and modeled future trajectories forced by global climate model projections. Populations rapidly declined in response to increasing sea surface temperatures and other factors across diverse model assumptions and climate scenarios. Strong density dependence limited the number of salmon that survived early life stages, suggesting a potentially efficacious target for conservation effort. Other solutions require a better understanding of the factors that limit survival at sea. We conclude that dramatic increases in smolt survival are needed to overcome the negative impacts of climate change for this threatened species.
... The projected change in pH is consistent with prior pH projections for the CCS downscaled with the same RCP8.5 scenario using a ROMS model (Gruber et al., 2012;Hauri et al., 2013;Marshall et al., 2017;Turi et al., 2018). These projections were performed with different biogeochemical models described in Gruber et al. (2012) and Fennel et al. (2006Fennel et al. ( , 2008 and relied on multi-model means or individual ensemble members for the global models. ...
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Global projections for ocean conditions in 2100 predict that the North Pacific will experience some of the largest changes. Coastal processes that drive variability in the region can alter these projected changes but are poorly resolved by global coarse-resolution models. We quantify the degree to which local processes modify biogeochemical changes in the eastern boundary California Current System (CCS) using multi-model regionally downscaled climate projections of multiple climate-associated stressors (temperature, O2, pH, saturation state (Ω), and CO2). The downscaled projections predict changes consistent with the directional change from the global projections for the same emissions scenario. However, the magnitude and spatial variability of projected changes are modified in the downscaled projections for carbon variables. Future changes in pCO2 and surface Ω are amplified, while changes in pH and upper 200 m Ω are dampened relative to the projected change in global models. Surface carbon variable changes are highly correlated to changes in dissolved inorganic carbon (DIC), pCO2 changes over the upper 200 m are correlated to total alkalinity (TA), and changes at the bottom are correlated to DIC and nutrient changes. The correlations in these latter two regions suggest that future changes in carbon variables are influenced by nutrient cycling, changes in benthic–pelagic coupling, and TA resolved by the downscaled projections. Within the CCS, differences in global and downscaled climate stressors are spatially variable, and the northern CCS experiences the most intense modification. These projected changes are consistent with the continued reduction in source water oxygen; increase in source water nutrients; and, combined with solubility-driven changes, altered future upwelled source waters in the CCS. The results presented here suggest that projections that resolve coastal processes are necessary for adequate representation of the magnitude of projected change in carbon stressors in the CCS.
... Comparisons with the food web model outputs and food web modeling conducted in the Salish Sea and the West Coast, respectively (Busch et al., 2013;Busch and McElhany, 2016;Marshall et al., 2017), delineate the most sensitive species, i.e., pteropods and Dungeness crabs. Furthermore, the experimental work by Busch et al. (2014) confirmed pteropod sensitivity to OA through increased shell dissolution and mortality. ...
Article
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Ocean acidification (OA) is projected to have profound impacts on marine ecosystems and resources, especially in estuarine habitats. Here, we describe biological risks under current levels of exposure to anthropogenic OA in the Salish Sea, an estuarine system that already experiences inherently low pH and aragonite saturation state (Ωar) conditions. We used the Pacific Northwest National Laboratory and Washington State Department of Ecology Salish Sea biogeochemical model (SSM) informed by a selection of OA-related biological thresholds of ecologically and economically important calcifiers, pteropods, and Dungeness crabs. The SSM was implemented to assess current exposure and associated risk due to reduced Ωar and pH conditions with respect to the magnitude, duration, and severity of exposure below the biological thresholds in the Salish Sea in comparison to the pre-industrial era. We further investigated the individual effects of atmospheric CO2 uptake and nutrient-driven eutrophication on changes in chemical exposure since pre-industrial times. Our model predicts average decreases in Ωar and pH since pre-industrial times of about 0.11 and 0.06, respectively, in the top 100 m of the water column of the Salish Sea. These decreases predispose pelagic calcifiers to increased duration, intensity, and severity of exposure. For pteropods, present-day exposure is below the thresholds related to sublethal effects across the entire Salish Sea basin, while mortality threshold exposure occurs on a spatially limited basis. The greatest risk for larval Dungeness crabs is associated with spatially limited exposures to low calcite saturation state in the South Sound in the springtime, triggering an increase in internal dissolution. The main anthropogenic driver behind the predicted impacts is atmospheric CO2 uptake, while nutrient-driven eutrophication plays only a marginal role over spatially and temporally limited scales. Reduction of CO2 emissions can help sustain biological species vital for ecosystem functions and society.
... In terms of biological processes, correlative species distribution models (SDM) has been successful for evaluating fishery impacts by measuring changes in spatial distribution over fishing grounds (Rogers et al., 2019;Selden et al., 2019), and although these models can account for species abundance (Muhling et al., 2019;Rogers et al., 2019), projecting species abundance far into the future remains a great challenge. Incorporating social-economic processes is more complex still (Lam, 2019), and projecting these systems ultimately relies on coupled end-to-end frameworks, with a general approach of scenario testing (Hollowed et al., 2020;Lindegren et al., 2010;Marshall et al., 2017). Clearly, long-term projection of climate impacts on fishery landings is immensely challenging, yet the value of such projections motivates development of alternative approaches to help identify these impacts. ...
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Many fish species are shifting spatial distributions in response to climate change, but projecting these shifts and measuring their impact at fine scales are challenging. We present a simulation that projects change in fishery landings due to spatial distribution shifts, by combining regional ocean and biogeochemical models (forced by three earth system models, ESMs: GFDL‐ESM2M, HadGEM2‐ES, IPSL‐CM5A‐MR), correlative models for species distribution and port‐level landings, and a simulation framework which provides realistic values for species abundance and fishery conditions using an historical “reference period”. We demonstrate this approach for the northern subpopulation of Pacific sardine, an iconic commercial species for the U.S. West Coast. We found a northward shift in sardine landings (based on the northern subpopulation's habitat suitability), with projected declines at southern ports (20%–50% decline by 2080) and an increase (up to 50%) or no change at northern ports, and this was consistent across the three ESMs. Total sardine landings were more uncertain, with HadGEM2 indicating a 20% decline from 2000 to 15 levels by 2070 (a rate of 170 mt/y), IPSL a 10% increase (115 mt/y), and GFDL an 15% increase by the year ~2050 followed by a sharp decrease. The ESMs also differed in their projected change to the timing of the fishing season and frequency of fishery closures. Our simulation also identified key constraints on future landings that can be targeted by more tactical assessment; these included the seasonality of quota allocation and the abundance of other species in the catch portfolio.
... (e.g., rays, sharks, river otters) (Jackson, 2001;Randall, 2003), providing a stark example of how overexploitation of important invertebrates can influence the wider ecosystem function and diversity. Looking forward, this knowledge gap is of considerable concern given the trajectory of increasing invertebrate fisheries combined with a greater vulnerability of many calcareous species to ocean acidification occurring under climate change (Marshall et al., 2017;Miller et al., 2017). ...
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Effective management of aquatic resources, wild and farmed, has implications for the livelihoods of dependent communities, food security, and ecosystem health. Good management requires information on the status of harvested species, yet many gaps remain in our understanding of these species and systems, in particular the lack of taxonomic resolution of harvested species. To assess these gaps we compared the occurrence of landed species (freshwater and marine) from the United Nations Food and Agriculture Organization (FAO) global fisheries production database to those in the International Union for Conservation of Nature (IUCN) Red List and the RAM Legacy Stock Assessment Database, some of the largest and most comprehensive global datasets of consumed aquatic species. We also quantified the level of resolution and trends in taxonomic reporting for all landed taxa in the FAO database. Of the 1,695 consumed aquatic species or groups in the FAO database considered in this analysis, a large portion (35%) are missing from both of the other two global datasets, either IUCN or RAM, used to monitor, manage, and protect aquatic resources. Only a small number of all fished taxa reported in FAO data (150 out of 1,695; 9%) have both a stock assessment in RAM and a conservation assessment in IUCN. Furthermore, 40% of wild caught landings are not reported to the species level, limiting our ability to effectively account for the environmental impacts of wild harvest. Landings of invertebrates (44%) and landings in Asia (>75%) accounted for the majority of harvest without species specific information in 2018. Assessing the overlap of species which are both farmed and fished to broadly map possible interactions-which can help or hinder wild populations-we found 296 species, accounting for 12% of total wild landings globally, and 103 countries and territories that have overlap in the species caught in the wild and produced through aquaculture. In all, our work highlights that while fisheries management is improving in many areas there remain key gaps in data resolution that are critical for fisheries assessments and conservation of aquatic systems into the future.
... This geological threshold is useful for understanding the implications of changes in ocean carbonate chemistry for living and nonliving calcium carbonate structures, and can also be applied to aragonite saturation state thresholds above 1 for species and/or species groups for which research has defined their sensitivity to changes in carbonate chemistry (e.g., Waldbusser et al. 2015;Bednaršek et al. 2019). Information on species sensitivity to OA conditions documented through laboratory experiments, modeling exercises, and limited field observations indicates that exposure to acidified conditions can increase coral bioerosion, change phytoplankton community composition, reduce recruitment of calcifying organisms, alter development and neurobiology of some fish species, and reorganize ecosystems (Kroeker et al. 2013;Busch and McElhany 2016;Marshall et al. 2017;Doo et al. 2020). These impacts will cascade into the tourism industry (reef diving), commercial fishery production (both bivalves and crustaceans), and subsistence use of reef fish, bivalves, and crustaceans (Doney et al. 2020). ...
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The U.S. Exclusive Economic Zone (EEZ) encompasses approximately 3.4 million square nautical miles of ocean and a coastline of over 12,300 miles. Along with the Great Lakes, this vast area generates ~US 370 billion of U.S. gross domestic product, 617 billion in sales and 2.6 million jobs each year. These ocean and coastal ecosystems also provide many important non-market services including subsistence food provisioning, health benefits, shoreline protection, climate regulation, conservation of marine biodiversity, and preservation of cultural heritage. As climatic changes occur, these benefits or ecosystem services may be significantly reduced or in some cases enhanced. These services are also under an array of pressures including over-exploitation of natural resources, pollution, and land use changes that occur simultaneously in synergistic, multiplicative, or antagonistic ways. This results in direct and indirect impacts that are often unpredictable across spatial and temporal scales. Here, we discuss a set of indicators designed in close collaboration with the U.S. National Climate Indicators System. Tracking the impacts via indicators will be essential to ensure long-term health of the marine environment and sustain the benefits to stakeholders who depend on marine ecosystem services.
... A key indicator of OA is aragonite saturation state, a measure of the availability of aragonite (a form of calcium carbonate). Aragonite saturation <1.0 indicates corrosive conditions that have been shown to be stressful for many CCE species, including oysters, crabs, and pteropods (Barton et al. 2012, Bednarsek et al. 2014, Marshall et al. 2017, Hodgson et al. 2018. Upwelling, which drives primary production in the CCE, also transports hypoxic, acidified waters from offshore onto the continental shelf, where increased community-level metabolic activity can further exacerbate OA (Chan et al. 2008, Feely et al. 2008. ...
... While the southern population experiences year-round upwelling, the N-CCS only experiences upwelling during the spring and summer (Bograd et al. 2009), so annual averaging reduces the overall vulnerability for the northern population. Other methodologies (e.g., ecosystem and economic modeling) have also been used to investigate the effects of future pH and OA on Dungeness crab in the CCS and have predicted negative impacts on survival, biomass, landings, and revenue (Busch & McElhany 2016, Marshall et al. 2017, Hodgson et al. 2018. These studies predicted more severe population impacts than our vulnerability assessment because they also factor in potential indirect effects of exposure to low pH, including changes in prey resources. ...
Thesis
Among global coastal regions, the Northern California Current System (N-CCS) is already experiencing effects from ocean acidification and hypoxia during the summer, primarily due to the region’s seasonal upwelling, current systems, and high productivity. Oxygen, pH, and temperature conditions are expected to become more stressful with continued fossil fuel emissions under global climate change, posing a serious threat to the region’s fisheries. N-CCS fishing communities rely heavily on the economically and culturally important Dungeness crab (Metacarcinus magister). The fishery is currently sustainably managed, but potential negative impacts from changing ocean conditions on Dungeness crab life stages and populations could have adverse effects for the fishery and the communities that rely on it. To quantify the vulnerability of Dungeness crab life stages and populations to predicted future conditions, both model projections and empirical experiments need to be employed. A semi-quantitative, life stage-specific framework was adapted here to assess the vulnerability of Dungeness crab to low pH, low dissolved oxygen, and high temperature under present and future projected conditions in the seasonally dynamic N-CCS. This was achieved using a combination of regional ocean models, species distribution maps, larval transport models, a population matrix model, and a literature review. This multi-faceted approach revealed that crab vulnerability to the three climate stressors will increase in the future (year 2100) under the most intense emissions scenario, with vulnerability to low oxygen being the most severe to the N-CCS population overall. Increases in vulnerability were largely driven by the adult life stage, which contributes the most to population growth. Empirical experiments demonstrated that adult crab respiration rates increase exponentially with temperature, potentially making this life stage more susceptible to hypoxia in the future. Together, this work provides novel insights into the effects of changing ocean conditions on Dungeness crab populations, which may help inform fishery management strategies.
... The projected change in pH is consistent with prior pH projections for the CCS downscaled with the same RCP 8.5 scenario using a ROMS model (Gruber et al., 2012;Hauri et al., 2013;Marshall et al., 2017;Turi et al., 2016). These projections were performed with different biogeochemical models described in Gruber et al. (2012), and Fennel et al. (2006 and relied 425 on multi-model means or individual ensemble members for the global models. ...
Preprint
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Global projections for ocean conditions in 2100 predict that the North Pacific will experience some of the largest changes. Coastal processes that drive variability in the region can alter these projected changes, but are poorly resolved by global coarse resolution models. We quantify the degree to which local processes modify biogeochemical changes in the eastern boundary California Current System (CCS) using multi-model regionally downscaled climate projections of multiple climate-associated stressors (temperature, O2, pH, Ω, and CO2). The downscaled projections predict changes consistent with the directional change from the global projections for the same emissions scenario. However, the magnitude and spatial variability of projected changes are modified in the downscaled projections for carbon variables. Future changes in pCO2 and surface Ω are amplified while changes in pH and upper 200 meter Ω are dampened relative to the projected change in global models. Within the CCS, differences in global and downscaled climate stressors are spatially variable, and the northern CCS experiences the most intense modification. These projected changes are consistent with source waters lower in oxygen, higher in nutrients, and in combination with solubility-driven changes, altered future upwelled waters in the CCS. The results presented here suggest coastal process resolving projections are necessary for adequate representation of the magnitude of projected change in pH and carbon stressors in the CCS.
... Other taxa have shown similar declines in abundance in response to increasing pCO 2 or acidity (Hall-Spencer et al., 2008;Cigliano et al., 2010;Kroeker et al., 2011). Measures of abundance are commonly used for zooplankton observations in time series, and relative shifts in species abundances have been used extensively to examine zooplankton responses to climate (e.g., Mackas et al., 2007;Mackas and Beaugrand, 2010;Peterson et al., 2017) and as input to models of food web and ecosystem response to OA (Busch et al., 2013;Marshall et al., 2017). Abundance data can also capture shifts in a species' center of abundance, indicating the directionality and magnitude of responses to climate change (Chivers et al., 2017). ...
Article
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Zooplankton can serve as indicators of ecosystem health, water quality, food web structure, and environmental change, including those associated with climate change and ocean acidification (OA). Laboratory studies demonstrate that low pH and high pCO 2 associated with OA can significantly affect the physiology and survival of zooplankton, with differential responses among taxa. While laboratory studies can be indicative of zooplankton response to OA, in situ responses will ultimately determine the fate of populations and ecosystems. In this perspective , we compare expectations from experimental studies with observations made in Puget Sound (Washington, United States), a highly dynamic estuary with known vulnerabilities to low pH and high pCO 2 . We found little association between empirical measures of in situ pH and the abundance of sensitive taxa as revealed by meta-analysis, calling into question the coherence between experimental studies and field observations. The apparent mismatch between laboratory and field studies has important ramifications for the design of long-term monitoring programs and interpretation and use of the data produced. Important work remains to be done to connect traits that are sensitive to OA with those that are ecologically relevant and reliably observable in the field.
... In light of the stakeholders' and managers' comments, ecosystem models have the potential to be used more routinely to assess the impact of changes in forage to dependent predators when linked to stock assessments (e.g., Drew et al., 2021) or MSE model output (e.g., Deroba et al., 2019), and to develop multispecies harvest control rules (HCRs) or ecosystem-level reference points (Link, 2018;Fulton et al., 2019;Holsman et al., 2020). This is in addition to their demonstrated utility in addressing specific strategic questions, such as the role of krill in the ecosystem (e.g., Pacific Fishery Management Council (PFMC), 2009) or the impact of climate change on PFMC-managed species (e.g., Marshall et al., 2017). However, in some cases, model refinements to include more realistic fishing scenarios based on current harvest rules or more realistic responses to environmental variability, particularly with regards to changes in species distribution, may be required before implementation ( Table 2). ...
Article
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One of the significant challenges to using information and ideas generated through ecosystem models and analyses for ecosystem-based fisheries management is the disconnect between modeling and management needs. Here we present a case study from the U.S. West Coast, the stakeholder review of NOAA’s annual ecosystem status report for the California Current Ecosystem established by the Pacific Fisheries Management Council’s Fisheries Ecosystem Plan, showcasing a process to identify management priorities that require information from ecosystem models and analyses. We then assess potential ecosystem models and analyses that could help address the identified policy concerns. We screened stakeholder comments and found 17 comments highlighting the need for ecosystem-level synthesis. Policy needs for ecosystem science included: (1) assessment of how the environment affects productivity of target species to improve forecasts of biomass and reference points required for setting harvest limits, (2) assessment of shifts in the spatial distribution of target stocks and protected species to anticipate changes in availability and the potential for interactions between target and protected species, (3) identification of trophic interactions to better assess tradeoffs in the management of forage species between the diet needs of dependent predators, the resilience of fishing communities, and maintenance of the forage species themselves, and (4) synthesis of how the environment affects efficiency and profitability in fishing communities, either directly via extreme events (e.g., storms) or indirectly via climate-driven changes in target species availability. We conclude by exemplifying an existing management process established on the U.S. West Coast that could be used to enable the structured, iterative, and interactive communication between managers, stakeholders, and modelers that is key to refining existing ecosystem models and analyses for management use.
... food availability; Fig. A.18). The inclusion of mechanistic responses to environmental conditions may allow our IBM to capture the effects of environmental stressors on populations as a whole, or on individuals in the context of climate change (Marshall et al., 2017;Doo et al., 2020). This approach may provide a detailed picture of the future and current effects of climate change on marine ecosystems, where the ongoing pteropod shell dissolution illustrates a concrete marine ecosystem response to climate change (Manno et al., 2017;Bednaršek et al., 2019). ...
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Shelled pteropods are cosmopolitan, free-swimming organisms of biogeochemical and commercial importance. They are widely used as sentinel species for the overall response of marine ecosystems to environmental stressors associated with climate change and changes in ocean chemistry. However, currently we are unable to project the effects of climate change on shelled pteropods at the population level, due to the missing spatio-temporal characterization of the response of pteropods to environmental stressors, and the limited information on the pteropod life history and life cycle. In this study, we implement a shelled pteropod Individual-Based Model (IBM), i.e. we simulate a pteropod population as a set of discrete individuals over several generations, life stages (eggs, larvae, juveniles and adults) and as a function of temperature, food availability and aragonite saturation state. The model is able to provide an abundance signal that is consistent with the abundance signal measured in the temperate region. In addition, the modeled life stage progression matches the reported size spectrum across the year, with two major spawning periods in spring and fall, and maturation in March and September. Furthermore, our IBM correctly predicts the abundance maxima of younger, smaller and potentially more susceptible life stages in spring and winter. Thus, our model provides a tool for advancing our understanding of the response of pteropod populations to future environmental changes.
... These are known as Large Ocean Management Areas in Canada (Oceans Act 1997) and Regional Planning Bodies in the United States (U.S. Executive Order 13547 [https: //obamawhitehouse.archives.gov/the-press-office/executiveorder-stewardship-ocean-our-coasts-and-great-lakes]). These planning areas are intended to increase interagency communication in these regions and have resulted in improved implementation of EBM principles in regional risk assessments (Marshall et al. 2017), fisheries management (Gaichas et al. 2018), and marine spatial planning (Clarke Murray et al. 2015). Long-term collaborative partnerships can also be built around these large regions, such as the Marine Plan Partnership (MaPP) in British Columbia. ...
Article
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Globally, ecosystem structure and function have been degraded by the cumulative effects (CE) of multiple stressors. To maintain ecosystem resilience, there is an urgent need to better account for CE in management decision‐making at various scales. Current laws and regulations are supported by a multitude of frameworks and strategies that vary in application and terminology use across management agencies and geopolitical boundaries. We synthesized management frameworks that accounted for CE in marine ecosystems at the regional and national levels across western North America (Canada, United States, Mexico) to identify similarities and shared challenges to successful implementation. We examined examples of solutions to the identified challenges (e.g., interagency and cross‐border partnerships to overcome challenges of managing for ecologically relevant spatial scales). Management frameworks in general consisted of 3 phases: scoping and structuring the system; characterizing relationships; and evaluating management options. Challenges in the robust implementation of these phases included lack of interagency coordination, minimal incorporation of diverse perspectives, and data deficiencies. Cases that provided solutions to these challenges encouraged coordination at ecological rather than jurisdictional scales, enhanced involvement of stakeholders and Indigenous groups, and used nontraditional data sources for decision‐making. Broader implementation of these approaches, combined with increased interagency and international coordination and collaboration, should facilitate the rapid advancement of more effective CE assessment and ecosystem management in North America and elsewhere. Implementación Práctica del Manejo de los Efectos Acumulativos de los Ecosistemas Marinos en el Oeste de América del Norte A nivel mundial, la estructura y función de los ecosistemas ha sido degradada por los efectos acumulativos (EA) de varios estresantes. Para mantener la resiliencia de los ecosistemas existe una necesidad urgente por explicar de mejor manera los EA en la toma de decisiones de manejo a varias escalas. Las leyes y normas actuales están respaldadas por una multitud de marcos y estrategias que varían en el uso de aplicaciones y terminología a través de las agencias de manejo y las fronteras geopolíticas. Sintetizamos los marcos de manejo para los EA en los ecosistemas marinos a nivel regional y nacional por todo el oeste de América del Norte (Canadá, Estados Unidos y México) para identificar las similitudes y los obstáculos compartidos para una implementación exitosa. Analizamos ejemplos de las soluciones a los obstáculos identificados (p. ej.: asociaciones interagencias o transfronterizas para sobrepasar los retos en el manejo para escalas espaciales ecológicamente relevantes). Los marcos de manejo consistieron generalmente de tres fases: exploración y estructuración del sistema; caracterización de las relaciones; y evaluación de las opciones de manejo. Los obstáculos para la implementación robusta de estas fases incluyeron la falta de coordinación entre agencias, la incorporación mínima de perspectivas diversas y deficiencias en la información. Los casos que proporcionaron soluciones a estos obstáculos fomentaron la coordinación a escalas ecológicas en lugar de sólo hacerlo en escalas jurisdiccionales, mejoraron la participación de los actores y los grupos indígenas y usaron fuentes de datos no tradicionales para la toma de decisiones. Una implementación más generalizada de estos enfoques, combinada con el incremento en la coordinación y colaboración interagencias e internacional, debería facilitar el rápido avance de evaluaciones más efectivas de los EA y del manejo de ecosistemas en América del Norte y en otras partes del mundo. 在全球范围内, 生态系统结构和功能正在因多重压力因素的累积效应 (CE) 而发生退化。为了维持生态系统恢复力, 我们迫切需要在各尺度的管理决策中更好地考虑累积效应。当前的法律法规已得到许多框架和战略的支持, 而这些框架和战略在不同管理机构和地理政治区的应用及术语使用方面仍存在差异。本研究综合了北美西部 (加拿大、美国、墨西哥) 区域和国家层面的海洋生态系统累积效应管理框架, 以确定成功的管理实施间的相似性及其面临的共同挑战。我们分析了对已知挑战的解决方案的案例, 如建立机构间和跨境伙伴关系以克服在生态相关空间尺度进行管理的挑战。管理框架一般包括三个阶段: 确定系统的范围和结构、描述关系, 以及评估管理方案。稳健实施这些阶段面临的挑战包括缺乏机构间协调、缺乏不同观点的整合和数据不足。解决这些挑战的方法包括鼓励在生态而非管辖范围内进行协调, 加强利益相关者和土著群体的参与, 以及使用非传统数据源进行决策。广泛实施这些方法并加强机构间和国际上的协调与合作, 将有助于在北美和其他地区快速推进更有效的累积效应评估和生态系统管理。【翻译: 胡怡思; 审校: 聂永刚】 关键词: 多重压力因素, 基于生态系统的管理, 环境影响评估, 加拿大, 美国, 墨西哥
... Other studies using ecosystem models of the Northeast Pacific also found amplified negative impacts on species abundance with multiple global change drivers (Ainsworth et al., 2011). Similarly, projections of OA impacts on the California Current ecosystem showed negative direct impacts on epibenthic invertebrates and downstream indirect impacts on higher trophic level species assemblages (Marshall et al., 2017). ...
Article
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Elevated atmospheric carbon dioxide (CO 2 ) is causing global ocean changes and drives changes in organism physiology, life-history traits, and population dynamics of natural marine resources. However, our knowledge of the mechanisms and consequences of ocean acidification (OA) – in combination with other climatic drivers (i.e., warming, deoxygenation) – on organisms and downstream effects on marine fisheries is limited. Here, we explored how the direct effects of multiple changes in ocean conditions on organism aerobic performance scales up to spatial impacts on fisheries catch of 210 commercially exploited marine invertebrates, known to be susceptible to OA. Under the highest CO 2 trajectory, we show that global fisheries catch potential declines by as much as 12% by the year 2100 relative to present, of which 3.4% was attributed to OA. Moreover, OA effects are exacerbated in regions with greater changes in pH (e.g., West Arctic basin), but are reduced in tropical areas where the effects of ocean warming and deoxygenation are more pronounced (e.g., Indo-Pacific). Our results enhance our knowledge on multi-stressor effects on marine resources and how they can be scaled from physiology to population dynamics. Furthermore, it underscores variability of responses to OA and identifies vulnerable regions and species.
... Increased exposure to novel diseases throughout the species' range is an additional possible outcome of climate change (Simmonds and Eliott 2009). A concern related to climate change, increasing ocean acidification, is currently not considered an important future threat to marine mammals off western North America (Marshall et al. 2017). ...
Technical Report
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Gray whales in the North Pacific are divided into two populations (or stocks) known as the Eastern North Pacific (ENP) and Western North Pacific (WNP) populations. Both were severely depleted prior to the mid-20th century by harvest during the whaling era. The ENP population migrates along the Pacific coast of North America between summer feeding grounds in the Bering, Beaufort and Chukchi Seas and wintering sites along western Baja California and the southern Gulf of California in Mexico, where mating and calving occur. This stock has recovered from the impacts of whaling and was federally delisted by the U.S. in 1994. It held an estimated 26,960 whales in 2016, when it was believed to exist at or near carrying capacity, but declined to an estimated 20,580 animals in 2019-2020. Within the ENP population, a small aggregation of about 232 individuals known as the Pacific Coast Feeding Group (PCFG) has been identified. These whales show regular fidelity during the summer and fall feeding season to waters along the coasts of northern California, Oregon, Washington, and Vancouver Island, British Columbia, and occasionally as far north as Kodiak Island, Alaska. Genetic testing indicates some differentiation from the greater ENP population, but PCFG whales likely interbreed with other ENP whales, and the PCFG is still considered a feeding aggregation of the ENP population. The WNP population, which is federally classified as endangered by the U.S., primarily feeds in summer in the Sea of Okhotsk and off the southeastern coast of the Kamchatka Peninsula in the Bering Sea, and is presumed to winter off the coast of China. Abundance, calculated in 2016 to be roughly 271 to 311 individuals one year and older, remains far below pre-whaling numbers. Research since 2004 has detected some members of this population migrating along the Pacific coast of North America to feeding and wintering grounds used by the ENP population. Gray whales face a number of known or potential threats such as entanglement in fishing gear and marine debris, ship strikes, human-generated marine sound, and climate change. Because of these threats, the small size of the WNP population and its federal endangered status, and the substantial level of uncertainty pertaining to the PCFG’s possible status as a separate stock under the Marine Mammal Protection Act, it is recommended that gray whales as a species be retained as a state sensitive species in Washington. However, uplisting to a higher level of protection may be warranted in the future if continuing research determines that WNP whales regularly migrate through Washington’s waters and/or the PCFG is classified as a separate stock.
... Increased exposure to novel diseases throughout the species' range is another possible outcome of climate change (Simmonds and Eliott 2009). Marshall et al. (2017) modelled ocean acidification impacts due to climate change and concluded that pelagic species (including humpbacks and other marine mammals) may be much less influenced by future pH levels than other species, especially epibenthic invertebrates and demersal fishes. ...
Technical Report
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The humpback whale is found in nearly all of the world’s oceans and undertakes long distance migrations between winter breeding grounds in tropical and subtropical waters and summer feeding grounds in high-latitude waters. Humpbacks were heavily exploited worldwide during the whaling era, including in Washington. By the time the species received global protection in 1966, North Pacific populations were severely depleted, with estimates of only 1,200 to 1,400 individuals remaining. Since then, these populations have rebounded to an estimated 16,000 to 21,000 animals, although some stocks have recovered more successfully than others. Humpback whales have been listed as a state endangered species in Washington since 1981. In 2016, the National Marine Fisheries Service identified 14 Distinct Population Segments (DPSs) worldwide, three of which visit Washington’s waters. These include (1) the Mexico DPS, which comprises 27.9% of humpback whales present in the state and is federally threatened, (2) the Central America DPS, which contributes the fewest animals (8.7%) among Washington’s humpbacks and is federally endangered, and (3) the Hawaii DPS, which comprises 63.5% of the humpbacks visiting Washington and is not federally listed. Humpbacks in the North Pacific remain vulnerable to a number of threats, including entanglement in fishing gear and marine debris, ship strikes, human-generated marine sound, the effects of climate change, and for the Central America DPS, possible issues related to small population size. Although humpback whales have rebounded since the cessation of whaling, the Central America DPS and Mexico DPS, which together comprise 36.6% of the humpbacks that visit Washington waters, remain below sustainable numbers and continue to be federally listed as endangered and threatened, respectively. Due to their federal status and the threats and uncertainties described in this report, it is recommended that this species be retained as a state endangered species in Washington.
... However, the fish communities in estuaries face high pressure due to overfishing and changes in environmental conditions (Duan et al., 2009;Cornwall and Eddy, 2015;Gobler and Baumann, 2016). Acidification and hypoxia in bottom water in temperate and tropical estuaries were frequently reported (Gobler and Baumann, 2016;Marshall et al., 2017). ...
Article
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Fishery resources are threatened by environmental changes and anthropogenic pressures, particularly in coastal ecosystems. It is crucial to understand the changes of fish communities and their responses to environmental changes and human disturbances to formulate rational fisheries and ecosystem-based management. The Pearl River Estuary (PRE) is a typical sub-tropic coastal ecosystem located in the center of the Guangdong-Hong Kong-Macao Greater Bay Area in the northern South China Sea. The demersal fish in the PRE is traditionally targeted as commercial fishing and severely impacted by overexploitation and hypoxia in the last few decades. In this study, we analyze the fish survey data during the period of 2020~2021 using multivariate statistics to investigate the impacts of human disturbances on the species and functional dynamics of the demersal fish community in the PRE. The results reveal that dissolved oxygen and temperature have significant correlations with the functional traits of the demersal fish community. The impacts of hypoxia on the demersal fish vary with species and locations. We found that the mean functional redundancy of the demersal fish community in the PRE was high across three surveys, but the functional diversity was low in this region. The abundance and richness of the demersal fish community increased during the summer fishing moratorium in the South China Sea in 2021, but the functional diversity did not increase significantly. We conclude that the high functional redundancy in the PRE might not be sufficient to buffer against environmental disturbances because of its low functional diversity. Our study highlights the complicated interactions between the demersal fish community and disturbances in the PRE. Understanding the traits structure and functional diversity of the fish community can help elucidate the factors determining the dynamic responses of the fish community to disturbances.
... In recent decades, anthropogenic climate change has had increasing effects on the ocean; ocean warming, ocean acidi cation, and ocean deoxygenation are three primary stressors that are impacting ocean biogeochemistry globally ( and additional climate change-related stressors has synergistic effects on marine ecosystems that vary by region, including altered food-web dynamics, community composition, and energy ows, as well as a potential reduction in the ecosystem services provided by marine systems (Gruber 2011;Doney et al. 2012; Popova et al. 2016). In order to develop effective mitigation and conservation strategies, climate change impacts must be investigated further on a regional and local basis (Marshall et al. 2017). ...
Preprint
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In Washington State, climate change will reshape the Puget Sound marine ecosystem through bottom-up and top-down processes, directly affecting species at all trophic levels. To better understand future climate change effects on sea surface temperature and salinity in Puget Sound, we used empirical downscaling to derive high-resolution time series of future sea surface temperature and salinity. Downscaling was based on scenario outputs of two coarse-resolution General Circulation Models, GFDL-CM4 and CNRM-CM6-1-HR, developed as part of the Coupled Model Intercomparison Project Phase 6 (CMIP6). We calculated 30-year climatologies for historical and future simulations, calculated the anomalies between historical and future projections, interpolated to a high resolution, and applied the resulting downscaled anomalies to a Regional Ocean Modeling System (ROMS) time series, yielding short-term (2020–2050) and long-term (2070–2100) delta-downscaled forecasts. Downscaled output for Puget Sound showed temperature and salinity variability between scenarios and models, but overall, there was strong model agreement. Model variability and uncertainty was higher for long-term projections. Spatially, we found regional differences for both temperature and salinity, including higher temperatures in the South Basin of Puget Sound and higher salinity in the North Basin. This study is a first step to translating CMIP6 outputs to higher resolution predictions of future conditions in Puget Sound. Interpreting downscaled projections of temperature and salinity in Puget Sound will help inform future ecosystem-based management decisions, such as supporting end-to-end ecosystem modeling simulations and assessing local-scale exposure risk to climate change.
... Aragonite is more soluble than other types of calcium carbonate (i.e., calcite), and thus, conditions can become corrosive to aragonite-producing organisms relatively quickly with increasing CO2. California Current Ecosystem species, including oysters, crabs, and pteropods, have shells and carapaces containing calcium carbonate and are, thus, vulnerable to decreasing saturation states (and increasing corrosivity to calcium carbonate) (Feely et al., 2008;Barton et al., 2012;Bednaršek et al., 2014;Feely et al., 2016Feely et al., , 2018Marshall et al., 2017;Hodgson et al., 2018). ...
Technical Report
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The purpose of a condition report is to use the best available science and most recent data to assess the status and trends of various parts of the sanctuary’s ecosystem. The first condition report for OCNMS was released in 2008 (Office of National Marine Sanctuaries [ONMS], 2008); ratings from that report are provided in Appendix C. This updated condition report marks a second comprehensive description of the status and trends of sanctuary resources and ecosystem services. The findings in this condition report document status and trends in water quality, habitat, living resources, maritime heritage resources, and ecosystem services from 2008–2019, unless otherwise noted. The report helps identify gaps in current monitoring efforts, as well as causal factors that may require monitoring, and potential remediation through management actions in coming years. The data discussed will not only enable sanctuary resource managers and stakeholders to acknowledge and have a shared perspective on prior changes in resource status, but will also inform management efforts to address challenges stemming from pressures, such as increasing coastal populations and climate change.
... Periáñez et al. 2013;Chen and Liu 2017;Li et al. 2018), ecosystems and fisheries (e.g. Marshall et al. 2017;Whomersley et al. 2018) and marine renewable energy (e.g. Adcock et al. 2015;Neill et al. 2018;Mackie et al. 2020a;Wang and Yang 2020), as well as underpinning the modelling of coastal hazards including storm surges (Flather 2000). ...
Article
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Calibration with respect to a bottom friction parameter is standard practice within numerical coastal ocean modelling. However, when this parameter is assumed to vary spatially, any calibration approach must address the issue of overfitting. In this work, we derive calibration problems in which the control parameters can be directly constrained by available observations, without overfitting. This is achieved by carefully selecting the ‘experiment design’, which in general encompasses both the observation strategy, and the choice of control parameters (i.e. the spatial variation of the friction field). In this work we focus on the latter, utilising existing observations available within our case study regions. We adapt a technique from the optimal experiment design (OED) literature, utilising model sensitivities computed via an adjoint-capable numerical shallow water model, Thetis . The OED method uses the model sensitivity to estimate the covariance of the estimated parameters corresponding to a given experiment design, without solving the corresponding parameter estimation problem. This facilitates the exploration of a large number of such experiment designs, to find the design producing the tightest parameter constraints. We take the Bristol Channel as a primary case study, using tide gauge data to estimate friction parameters corresponding to a piecewise-constant field. We first demonstrate that the OED framework produces reliable estimates of the parameter covariance, by comparison with results from a Bayesian inference algorithm. We subsequently demonstrate that solving an ‘optimal’ calibration problem leads to good model performance against both calibration and validation data, thus avoiding overfitting.
... Other methodologies (e.g., ecosystem and economic modeling) have also been used to investigate the effects of future pH and OA on Dungeness crab in the CCS and have predicted negative impacts on survival, biomass, landings, and revenue (Busch & McElhany, 2016;Hodgson et al., 2018;Marshall et al., 2017). These studies factored in potential indirect effects of lower pH environments, including changes in prey resources, and all suggest that Dungeness crab populations will be negatively affected by future OA. ...
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Plain Language Summary The release of carbon dioxide (CO2) into the atmosphere by human activities is altering ocean conditions including pH, oxygen, and temperature. One way to understand how these changing conditions will affect ecologically, economically, and culturally important marine species is to scale individual responses from laboratory experiments to population‐level impacts. In this study, we assessed the vulnerability of Dungeness crab, one of the most valuable fisheries in the NW USA, to stressful conditions based on the predicted habitat exposure and response of each life stage (eggs, larvae, juveniles, and adults). The degree of vulnerability was determined by the seasonality of the ocean conditions in combination with the crab's complex life cycle. This approach revealed that Dungeness crab life stages and populations will be more vulnerable to low pH, low oxygen, and high temperature in the future (year 2100) under an aggressive CO2 emissions scenario. Based on these results, we recommend that fishery managers incorporate changing conditions into their decision‐making to protect vulnerable life stages in areas prone to stressful conditions (e.g., adult crabs in hypoxic areas). Our approach can be adapted for many other economically and ecologically important marine species in order to inform conservation and management strategies.
... The anomalous warm waters are correlated with widespread ecological changes, including a northward shift of southern, warm-water species(Morgan et al. 2019, Sanford et al. 2019), a coast-wide outbreak of toxic algae led to west coast Dungeness crab fishery delays and record entanglements with large whales (Santora et al. 2020), urchin outbreaks and loss in kelp cover in northern California causing closure of the red abalone fishery (Rogers-Bennett et al. 2019, McPherson et al. 2021), kelp decline throughout the region (Arafeh-Dalmau et al. 2020, Beas-Luna et al. 2020b), shifts in sea urchin diversity and recruitment, and abalone recruitment in southern California (Kawana et al. 2019, Okamoto et al. 2020), outbreaks of sea star wasting disease (Menge et al. 2016, Miner et al. 2018, Aalto et al. 2020, Aquino et al. 2021), and seabird and marine mammal unusual mortality events (Laake et al. 2018, NOAA Fisheries 2020).This event was a climate stress-test, potentially indicative of future conditions under climate change, yet we do not know the extent or duration of the ecosystem perturbations. These large-scale changes and novel interactions (e.g., Dungeness crab fishery operations and whale migrations) may offer a glimpse into future ecosystem responses to climate changes predicted for the California Current(Marshall et al. 2017, Xiu et al. 2018. Climate change scenarios for the California Current that reflect potential future ecosystem responses are included in a report Readying California Fisheries for Climate Change(Chavez et al. 2017, Box 4). ...
Technical Report
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This report was produced by a working group of the Ocean Protection Council’s Science Advisory Team (OPC SAT) and Ocean Science Trust on behalf of the Ocean Protection Council (OPC), California Department of Fish and Wildlife (CDFW), and Fish and Game Commission (FCG). In preparation for the first adaptive management review of California’s MPA network, to be undertaken by CDFW in 2022, Ocean Science Trust convened an expert working group to explore the role of California’s MPAs and MPA Network in imparting climate resilience. This working group was convened in parallel to the MPA Decadal Evaluation Working Group, tasked with developing scientific guidance that will be integral in supporting the decadal management review of the MPA network in 2022.
... food availability; Fig. A.18). The inclusion of mechanistic responses to environmental conditions may allow our IBM to capture the effects of environmental stressors on populations as a whole, or on individuals in the context of climate change (Marshall et al., 2017;Doo et al., 2020). This approach may provide a detailed picture of the future and current effects of climate change on marine ecosystems, where the ongoing pteropod shell dissolution illustrates a concrete marine ecosystem response to climate change (Manno et al., 2017;Bednaršek et al., 2019). ...
Article
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Shelled pteropods are cosmopolitan, free-swimming organisms of biogeochemical and commercial importance. They are widely used as sentinel species for the overall response of marine ecosystems to environmental stressors associated with climate change and changes in ocean chemistry. However, currently we are unable to project the effects of climate change on shelled pteropods at the population level, due to the missing spatio-temporal characterization of the response of pteropods to environmental stressors, and the limited information on the pteropod life history and life-cycle. In this study, we implement a shelled pteropod Individual-Based Model (IBM), i.e. we simulate a pteropod population as a set of discrete individuals over several generations, life-stages (eggs, larvae, juveniles and adults) and as a function of temperature, food availability, and aragonite saturation state. The model is able to provide an abundance signal that is consistent with the abundance signal measured in the temperate region. In addition, the modeled life-stage progression matches the reported size spectrum across the year, with two major spawning periods in spring and fall, and maturation in March and September. Furthermore, our IBM correctly predicts the abundance maxima of younger, smaller and potentially more susceptible life-stages in spring and winter. Thus, our model provides a tool for advancing our understanding of the response of pteropod populations to future environmental changes.
Article
The California Current Marine Ecosystem is a highly productive system that exhibits strong natural variability and vulnerability to anthropogenic climate trends. Relating projections of ocean change to biological sensitivities requires detailed synthesis of experimental results. Here, we combine measured biological sensitivities with high‐resolution climate projections of key variables (temperature, oxygen, and pCO2) to identify the direction, magnitude, and spatial distribution of organism‐scale vulnerabilities to multiple axes of projected ocean change. Among 12 selected species of cultural and economic importance, we find that all are sensitive to projected changes in ocean conditions through responses that affect individual performance or population processes. Response indices were largest in the northern region and inner shelf. While performance traits generally increased with projected changes, fitness traits generally decreased, indicating that concurrent stresses can lead to fitness loss. For two species, combining sensitivities to temperature and oxygen changes through the Metabolic Index shows how aerobic habitat availability could be compressed under future conditions. Our results suggest substantial and specific ecological susceptibility in the next 80 years, including potential regional loss of canopy‐forming kelp, changes in nearshore food webs caused by declining rates of survival among red urchins, Dungeness crab, and razor clams, and loss of aerobic habitat for anchovy and pink shrimp. We also highlight fillable gaps in knowledge, including specific physiological responses to stressors, variation in responses across life stages, and responses to multistressor combinations. These findings strengthen the case for filling information gaps with experiments focused on fitness‐related responses and those that can be used to parameterize integrative physiological models, and suggest that the CCME is susceptible to substantial changes to ecosystem structure and function within this century. This work summarizes experimental results of biological responses to projected climate change in species of economic, cultural, and ecological importance along the US and Canadian west coast, and combines these with downscaled climate projections. While physiological rates generally increased with projected changes, fitness traits generally decreased, indicating that concurrent stresses can lead to fitness loss, and anticipated ecological change in the California Current Marine Ecosystem.
Article
Accurately representing the bottom friction effect is a significant challenge in numerical tidal models. Bottom friction effects are commonly defined via parameter estimation techniques. However, the bottom friction coefficient (BFC) can be related to the roughness of the sea bed. Therefore, sedimentological data can be beneficial in estimating BFCs. Taking the Bristol Channel and Severn Estuary as a case study, we perform a number of BFC parameter estimation experiments, utilising sedimentological data in a variety of ways. Model performance is explored through the results of each parameter estimation experiment, including applications to tidal range and tidal stream resource assessment. We find that theoretically derived sediment-based BFCs are in most cases detrimental to model performance. However, good performance is obtained by retaining the spatial information provided by the sedimentological data in the formulation of the parameter estimation experiment; the spatially varying BFC can be represented as a piecewise-constant field following the spatial distribution of the observed sediment types. By solving the resulting low-dimensional parameter estimation problem, we obtain good model performance as measured against tide gauge data. This approach appears well suited to modelling tidal range energy resource, which is of particular interest in the case study region. However, the applicability of this approach for tidal stream resource assessment is limited, since modelled tidal currents exhibit a strong localised response to the BFC; the use of piecewise-constant (and therefore discontinuous) BFCs is found to be detrimental to model performance for tidal currents.
Article
Dungeness crab (Metacarcinus magister) are the most valuable fishery on the U.S. West Coast and both larval and adult Dungeness crabs are important components of regional food webs. Previous experiments have shown decreased survival and a slower development rate for Dungeness crab zoea reared in water with high CO2, indicating a susceptibility to ocean acidification. In this study we reared late-stage megalopae and juvenile Dungeness crabs in both ambient and high CO2 conditions for over 300 days. Counter to expectations, crabs reared in high CO2 had a higher survival rate than those reared in ambient conditions and crabs in high CO2 transitioned more quickly in one of the stages (J5 to J6). However, crabs reared in high CO2 were generally smaller and had a higher resting metabolic rate than crabs in ambient CO2. We hypothesized that two separate mechanisms were in effect, with one process driving survival and a second process driving size and respiration rate. We further hypothesized that increased mortality in ambient CO2 could be caused by a CO2-sensitive microbial pathogen, but that size and respiration differences were caused by the direct effects of CO2 on the crabs themselves. Overall, the zoea stages seem more sensitive to CO2 than the megalopae and juvenile stages.
Preprint
Accurately representing the bottom friction effect is a significant challenge in numerical tidal models. Bottom friction effects are commonly defined via parameter estimation techniques. However, the bottom friction coefficient (BFC) can be related to the roughness of the sea bed. Therefore, sedimentological data can be beneficial in estimating BFCs. Taking the Bristol Channel and Severn Estuary as a case study, we perform a number of BFC parameter estimation experiments, utilising sedimentological data in a variety of ways. Model performance is explored through the results of each parameter estimation experiment, including applications to tidal range and tidal stream resource assessment. We find that theoretically derived sediment-based BFCs are in most cases detrimental to model performance. However, good performance is obtained by retaining the spatial information provided by the sedimentological data in the formulation of the parameter estimation experiment; the spatially varying BFC can be represented as a piecewise-constant field following the spatial distribution of the observed sediment types. By solving the resulting low-dimensional parameter estimation problem, we obtain good model performance as measured against tide gauge data. This approach appears well suited to modelling tidal range energy resource, which is of particular interest in the case study region. However, the applicability of this approach for tidal stream resource assessment is limited, since modelled tidal currents exhibit a strong localised response to the BFC; the use of piecewise-constant (and therefore discontinuous) BFCs is found to be detrimental to model performance for tidal currents.
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The Arctic may be particularly vulnerable to the consequences of both ocean acidification (OA) and global warming, given the faster pace of these processes in comparison with global average speeds. Here, we use the Atlantis ecosystem model to assess how the trophic network of marine fishes and invertebrates in the Icelandic waters is responding to the combined pressures of OA and warming. We develop an approach where we first identify species by their economic (catch value), social (number of participants in fisheries), or ecological (keystone species) importance. We then use literature-determined ranges of sensitivity to OA and warming for different species and functional groups in the Icelandic waters to parametrize model runs for different scenarios of warming and OA. We found divergent species responses to warming and acidification levels; (mainly) planktonic groups and forage fish benefited while (mainly) benthic groups and predatory fish decreased under warming and acidification scenarios. Assuming conservative harvest rates for the largest catch-value species, Atlantic cod, we see that the population is projected to remain stable under even the harshest acidification and warming scenario. Further, for the scenarios where the model projects reductions in biomass of Atlantic cod, other species in the ecosystem increase, likely due to a reduction in competition and predation. These results highlight the interdependencies of multiple global change drivers and their cascading effects on trophic organization, and the continued high abundance of an important species from a socio-economic perspective in the Icelandic fisheries.
Article
Although there has been an increase in the research of social-ecological systems, there are still many gaps to understand the effects of change within coastal communities and ecosystems. The drivers of change include climate change, management regulations, demographic shifts, and market trends, and their intersectionality and, ultimately, impacts on commercial fishing communities are poorly understood. The research presented here explores connections between climate change and the increase in the average age of commercial fishermen, referred to as “graying of the fleet”. Ultimately, these connections inform our overall objective: to understand how cumulative impacts from these two ongoing phenomena affect the resilience and adaptive capacity of the fishing community. Parsing out the connections may help managers or policy makers more accurately conceptualize future scenarios of community change and simultaneously enables the location of specific target areas for intervention or opportunity. Oral history semi-structured interviews with members of Oregon’s fishing community were analyzed and recent climate change projections from the literature were synthesized to parameterize a set of possible scenarios regarding impacts on the fishing community. Results indicate that climate change will likely intensify both the stressors contributing to and the impacts of the graying of the fleet in Oregon. Analysis of the cumulative impacts from climate change and graying of the fleet reveal a greater impact on resilient and adaptive capacities of Oregon’s fishing community than analysis of the drivers individually indicates. Therefore, an important implication from this research is the need to evaluate cumulative impacts within these coupled social-ecological systems. Relying on the responsive adaptability of fishing community members alone may not be sufficient, as their resilience and capacity to do so could be limited in the future.
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As climate change accelerates and fisheries management continues to evolve, California's commercial fisheries are changing. To improve the understanding of recent California fisheries dynamics, we compiled and analyzed commercial landings receipts to characterize temporal and spatial variation in landing and value of key fisheries groups within the exclusive economic zone across the state from 2005 to 2019. We found that California fisheries continue a shift first observed in the 1980s from higher‐biomass, lower‐value species, such as coastal pelagic species and market squid, toward lower‐biomass, higher‐value species, such as Dungeness crab Cancer magister and groundfish. Over the 15‐year time series analyzed, total landings declined by nearly two‐thirds but total value remained relatively stable, likely due to a focus on higher value species and rising prices. The northern half of the state has become much more economically valuable, accounting for over 50% of total value across the state in 2019. A case study analysis found groundfish to be the dominant fisheries in the two areas that have been identified as priorities for potential offshore wind development in central and northern California. Our results elucidate the most recent status and trends of California's commercial fisheries, over time, across space, and among different fisheries groups, providing valuable information for informing fisheries management and marine spatial planning.
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Ocean acidification (OA) has the potential to restructure ecosystems due to variation in species sensitivity to the projected changes in ocean carbon chemistry. Ecological models can be forced with scenarios of OA to help scientists, managers, and other stakeholders understand how ecosystems might change. We present a novel methodology for developing estimates of species sensitivity to OA that are regionally specific, and applied the method to the California Current ecosystem. To do so, we built a database of all published literature on the sensitivity of temperate species to decreased pH. This database contains 393 papers on 285 species and 89 multi-species groups from temperate waters around the world. Research on urchins and oysters and on adult life stages dominates the literature. Almost a third of the temperate species studied to date occur in the California Current. However, most laboratory experiments use control pH conditions that are too high to represent average current chemistry conditions in the portion of the California Current water column where the majority of the species live. We developed estimates of sensitivity to OA for functional groups in the ecosystem, which can represent single species or taxonomically diverse groups of hundreds of species. We based these estimates on the amount of available evidence derived from published studies on species sensitivity, how well this evidence could inform species sensitivity in the California Current ecosystem, and the agreement of the available evidence for a species/species group. This approach is similar to that taken by the Intergovernmental Panel on Climate Change to characterize certainty when summarizing scientific findings. Most functional groups (26 of 34) responded negatively to OA conditions, but when uncertainty in sensitivity was considered, only 11 groups had relationships that were consistently negative. Thus, incorporating certainty about the sensitivity of species and functional groups to OA is an important part of developing robust scenarios for ecosystem projections.
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Millions of people rely on the ecosystem services provided by coral reefs, but sustaining these benefits requires an understanding of how reefs and their biotic communities are affected by local human-induced disturbances and global climate change. Ecosystem-based management that explicitly considers the indirect and cumulative effects of multiple disturbances has been recommended and adopted in policies in many places around the globe. Ecosystem models give insight into complex reef dynamics and their responses to multiple disturbances and are useful tools to support planning and implementation of ecosystem-based management. We adapted the Atlantis Ecosystem Model to incorporate key dynamics for a coral reef ecosystem around Guam in the tropical western Pacific. We used this model to quantify the effects of predicted climate and ocean changes and current levels of current land-based sources of pollution (LBSP) and fishing. We used the following six ecosystem metrics as indicators of ecosystem state, resilience and harvest potential: 1) ratio of calcifying to non-calcifying benthic groups, 2) trophic level of the community, 3) biomass of apex predators, 4) biomass of herbivorous fishes, 5) total biomass of living groups and 6) the end-to-start ratio of exploited fish groups. Simulation tests of the effects of each of the three drivers separately suggest that by mid-century climate change will have the largest overall effect on this suite of ecosystem metrics due to substantial negative effects on coral cover. The effects of fishing were also important, negatively influencing five out of the six metrics. Moreover, LBSP exacerbates this effect for all metrics but not quite as badly as would be expected under additive assumptions, although the magnitude of the effects of LBSP are sensitive to uncertainty associated with primary productivity. Over longer time spans (i.e., 65 year simulations), climate change impacts have a slight positive interaction with other drivers, generally meaning that declines in ecosystem metrics are not as steep as the sum of individual effects of the drivers. These analyses offer one way to quantify impacts and interactions of particular stressors in an ecosystem context and so provide guidance to managers. For example, the model showed that improving water quality, rather than prohibiting fishing, extended the timescales over which corals can maintain high abundance by at least 5-8 years. This result, in turn, provides more scope for corals to adapt or for resilient species to become established and for local and global management efforts to reduce or reverse stressors.
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Characterization of the diets of upper-trophic pelagic predators that consume forage species is a key ingredient in the development of ecosystem-based fishery management plans, conservation of marine predators, and ecological and economic modeling of trophic interactions. Here we present the California Current Predator Diet Database (CCPDD) for the California Current region of the Pacific Ocean over the past century, assimilating over 190 published records of predator food habits for over 100 predator species and 32 categories of forage taxa (species or groups of similar species). Literature searches targeted all predators that consumed forage species: seabirds, cetaceans, pinnipeds, bony and cartilaginous fishes, and a predatory invertebrate. Diet data were compiled into a relational database. Analysis of the CCPDD highlighted differences in predator diet data availability based on geography, time period and predator taxonomy, as well as prominent prey categories. The top 5 forage taxa with the most predators included juvenile rockfish, northern anchovy, euphausiid krill, Pacific herring and market squid. Predator species with abundant data included Pacific hake, common murre, and California sea lion. Most diet data were collected during the summer; the lack of winter data will restrict future use of the CCPDD to understand seasonal patterns in predator diet unless more such data become available. Increased synthesis of historical information can provide new resources to understand patterns in the role of forage species in predator diet. Increased publication and/or accessibility of long-term datasets and data-sharing will further foster the synthesis of information intended to inform the management, conservation and understanding of marine food webs.
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Busch, D. S., Harvey, C. J., and McElhany, P. 2013. Potential impacts of ocean acidification on the Puget Sound food web. – ICES Journal of Marine Science, 70: 823–833. Ecosystem impacts of ocean acidification (OA) were explored by imposing scenarios designed to mimic OA on a food web model of Puget Sound, a large estuary in northwestern USA. The productivity of functional groups containing mostly calcifiers was decreased while still allowing other species groups to respond to the scenarios in a dynamic way through indirect effects. Results focus on changes in ecosystem services and structure. Sometimes the direct and indirect effects of OA countered each other due to interactions between predators and prey within the food web, leading to little change in the food web. In other cases, direct and indirect effects caused greater change in the food web than anticipated from direct effects alone. Results were strongly affected by the group on which OA was directly imposed, with changes in copepod productivity being the most influential. While there is much uncertainty in our predictions, focusing on the complex interactions among species, and between species and their environment, will yield better understanding of how ecosystems may respond to OA.
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An ecosystem approach is widely seen as a desirable goal for fisheries management but there is little consensus on what strategies or measures are needed to achieve it. Management strategy evaluation (MSE) is a tool that has been widely used to develop and test single species fisheries management strategies and is now being extended to support ecosystem based fisheries management (EBFM). We describe the application of MSE to investigate alternative strategies for achieving EBFM goals for a complex multispecies fishery in southeastern Australia. The study was undertaken as part of a stakeholder driven process to review and improve the ecological, economic and social performance of the fishery. An integrated management strategy, involving combinations of measures including quotas, gear controls and spatial management, performed best against a wide range of objectives and this strategy was subsequently adopted in the fishery, leading to marked improvements in performance. Although particular to one fishery, the conclusion that an integrated package of measures outperforms single focus measures we argue is likely to apply widely in fisheries that aim to achieve EBFM goals.
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Anthropogenic CO2 emitted to the atmosphere is absorbed by the oceans, causing a progressive increase in ocean inorganic carbon concentrations and resulting in decreased water pH and calcium carbonate saturation. This phenomenon, called ocean acidification, is in addition to the warming effects of CO2 emissions. Ocean acidification has been reported to affect ocean biota, but the severity of this threat to ocean ecosystems (and humans depending on these ecosystems) is poorly understood. Here we evaluate the scale of this threat in the context of widely used representative concentration pathways (RCPs) by analysing the sensitivities of five animal taxa (corals, echinoderms, molluscs, crustaceans and fishes) to a wide range of CO2 concentrations. Corals, echinoderms and molluscs are more sensitive to RCP8.5 (936 ppm in 2100) than are crustaceans. Larval fishes may be even more sensitive than the lower invertebrates, but taxon sensitivity on evolutionary timescales remains obscure. The variety of responses within and between taxa, together with observations in mesocosms and palaeo-analogues, suggest that ocean acidification is a driver for substantial change in ocean ecosystems this century, potentially leading to long-term shifts in species composition.
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The physical climate formulation and simulation characteristics of two new global coupled carbon-climate Earth System Models, ESM2M and ESM2G, are described. These models demonstrate similar climate fidelity as the Geophysical Fluid Dynamics Laboratory's previous Climate Model version 2.1 (CM2.1) while incorporating explicit and consistent carbon dynamics. The two models differ exclusively in the physical ocean component; ESM2M uses Modular Ocean Model version 4p1 with vertical pressure layers while ESM2G uses Generalized Ocean Layer Dynamics with a bulk mixed layer and interior isopycnal layers. Differences in the ocean mean state include the thermocline depth being relatively deep in ESM2M and relatively shallow in ESM2G compared to observations. The crucial role of ocean dynamics on climate variability is highlighted in El Niño-Southern Oscillation being overly strong in ESM2M and overly weak in ESM2G relative to observations. Thus, while ESM2G might better represent climate changes relating to total heat content variability given its lack of long-term drift, gyre circulation, and ventilation in the North Pacific, tropical Atlantic, and Indian Oceans, and depth structure in the overturning and abyssal flows, ESM2M might better represent climate changes relating to surface circulation given its superior surface temperature, salinity, and height patterns, tropical Pacific circulation and variability, and Southern Ocean dynamics. The overall assessment is that neither model is fundamentally superior to the other, and that both models achieve sufficient fidelity to allow meaningful climate and earth system modeling applications. This affords the ability to assess the role of ocean configuration on earth system interactions in the context of two state-of-the-art coupled carbon- climate models.
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The authors describe carbon system formulation and simulation characteristics of two new global coupled carbon-climate Earth System Models (ESM), ESM2M and ESM2G. These models demonstrate good climate fidelity as described in part I of this study while incorporating explicit and consistent carbon dynamics. The two models differ almost exclusively in the physical ocean component; ESM2M uses the Modular Ocean Model version 4.1 with vertical pressure layers, whereas ESM2G uses generalized ocean layer dynamics with a bulk mixed layer and interior isopycnal layers. On land, both ESMs include a revised land model to simulate competitive vegetation distributions and functioning, including carbon cycling among vegetation, soil, and atmosphere. In the ocean, both models include new biogeochemical algorithms including phytoplankton functional group dynamics with flexible stoichiometry. Preindustrial simulations are spun up to give stable, realistic carbon cycle means and variability. Significant differences in simulation characteristics of these two models are described. Because of differences in oceanic ventilation rates, ESM2M has a stronger biological carbon pump but weaker northward implied atmospheric CO2 transport than ESM2G. The major advantages of ESM2G over ESM2M are improved representation of surface chlorophyll in the Atlantic and Indian Oceans and thermocline nutrients and oxygen in the North Pacific. Improved tree mortality parameters in ESM2G produced more realistic carbon accumulation in vegetation pools. The major advantages of ESM2M over ESM2G are reduced nutrient and oxygen biases in the southern and tropical oceans.
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Considerable progress has been made in integrating carbon, nutrient, phytoplankton and zooplankton dynamics into global-scale physical climate models. Scientists are exploring ways to extend the resolution of the biosphere within these Earth system models (ESMs) to include impacts on global distribution and abundance of commercially exploited fish and shellfish. This paper compares different methods for modeling fish and shellfish responses to climate change on global and regional scales. Several different modeling approaches are considered including: direct applications of ESM’s, use of ESM output for estimation of shifts in bioclimatic windows, using ESM outputs to force single- and multi-species stock projection models, and using ESM and physical climate model outputs to force regional bio-physical models of varying complexity and mechanistic resolution. We evaluate the utility of each of these modeling approaches in addressing nine key questions relevant to climate change impacts on living marine resources. No single modeling approach was capable of fully addressing each question. A blend of highly mechanistic and less computationally intensive methods is recommended to gain mechanistic insights and to identify model uncertainties.
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Experiments in which organisms are reared in treatments simulating current and future pCO2 concentrations are critical for ocean acidification (OA) research. The majority of OA exposure experiments use average atmospheric pCO2 levels as a baseline treatment. We conducted an ecoregion-scale analysis of global carbon chemistry datasets. For many locales, atmospheric pCO2 levels are not an appropriate characterization of marine carbon chemistry. We argue that atmospheric pCO2 should be disregarded when setting baseline treatment conditions and experimental design should rely on measurements of carbon chemistry in a study subject’s habitat. As carbon chemistry conditions vary with space and time, we suggest using a range of pCO2 values as a control rather than a single value. We illustrate this issue with data on the habitat of Euphausia pacifica, which currently lives in waters with a pCO2 around 900 μatm, a concentration much higher than the current global atmospheric mean.