Marine environmental history analyses the changing relationships between human societies and mari... more Marine environmental history analyses the changing relationships between human societies and marine natural resources over time. This is the first book which deals in a systematic way with the theoretical backgrounds of this discipline. Major theories and methods are introduced by leading scholars of the field. The book seeks to encapsulate some of the major novelties of this fascinating new discipline and its contribution to the management, conservation and restoration of marine and coastal ecosystems as well as the cultural heritages of coastal communities in different parts of the world.
The ICES Working Group on the History of Fish and Fisheries (WGHIST) is a forum for interdiscipli... more The ICES Working Group on the History of Fish and Fisheries (WGHIST) is a forum for interdisciplinary research on social-ecological change in marine and fisheries systems over multi-decadal to centennial timescales. WGHIST comprises a diverse group of researchers, including marine biologists, fisheries scientists, historians, and historical ecologists, from Europe and North America, as well as Australia, Russia, and South Africa. WGHIST provided a platform for the sharing and reporting of a wide range of research on marine and fisheries systems change over time, including the use of novel and non-traditional data sources and methodologies to identify and interpret these changes. WGHIST members also worked with the ICES Secretariat to forward digital tools to make historical resources more accessible and regarding WGHIST’s potential to support ICES Fisheries and Ecosystem Overviews. WGHIST engaged with the larger research community on the following manuscripts, still in development o...
Both costs and benefits must be considered when implementing marine protected areas (MPAs), parti... more Both costs and benefits must be considered when implementing marine protected areas (MPAs), particularly those associated with fishing effort displaced by potential closures. The Southern Ocean offers a case study in understanding such tradeoffs, where MPAs are actively being discussed to achieve a range of protection and sustainable use objectives. Here, we evaluated the possible impacts of two MPA scenarios on the Antarctic krill (Euphausia superba) fishery and krill-dependent predators in the Scotia Sea, explicitly addressing the displacement of fishing from closed areas. For both scenarios, we employed a minimally realistic, spatially explicit ecosystem model and considered three alternative redistributions of displaced fishing. We projected both MPAs to provide positive outcomes for many krill-dependent predators, especially when closed areas included at least 50-75% of their foraging distributions. Further, differences between the scenarios suggest ways to improve seal and penguin protection in the Scotia Sea. MPA scenarios also projected increases in total fishery yields, but alongside risks of fishing in areas where relatively low krill densities could cause the fishery to suspend operations. The three alternatives for redistributing displaced fishing had little effect on benefits to predators, but did matter for the fishery, with greater differences in overall catch and risk of fishing in areas of low krill density when displaced fishing was redistributed evenly among the open areas. Collectively, results suggest a well-designed MPA in the Scotia Sea may protect krill-dependent predators, even with displaced fishing, and preclude further spatial management of the krill fishery outside the MPA. More broadly, outcomes denote the importance of delineating fishing and predator habitat, spatial scales, and the critical trade-offs inherent in MPA development.
Climate change is a threat to marine ecosystems and the services they provide, and reducing fishi... more Climate change is a threat to marine ecosystems and the services they provide, and reducing fishing pressure is one option for mitigating the overall consequences for marine biota. We used a minimally realistic ecosystem model to examine how projected effects of ocean warming on the growth of Antarctic krill, Euphausia superba, might affect populations of krill and dependent predators (whales, penguins, seals, and fish) in the Scotia Sea. We also investigated the potential to mitigate depletion risk for predators by curtailing krill fishing at different points in the 21st century. The projected effects of ocean warming on krill biomass were strongest in the northern Scotia Sea, with a ≥40% decline in the mass of individual krill. Projections also suggest a 25% chance that krill biomass will fall below an established depletion threshold (75% of its unimpacted level), with consequent risks for some predator populations, especially penguins. Average penguin abundance declined by up to ...
Understanding how and when cooperative human behaviour forms in common-pool resource systems is c... more Understanding how and when cooperative human behaviour forms in common-pool resource systems is critical to illuminating social–ecological systems and designing governance institutions that promote sustainable resource use. Before assessing the full complexity of social dynamics, it is essential to understand, concretely and mechanistically, how resource dynamics and human actions interact to create incentives and pay-offs for social behaviours. Here, we investigated how such incentives for information sharing are affected by spatial dynamics and management in a common-pool resource system. Using interviews with fishermen to inform an agent-based model, we reveal generic mechanisms through which, for a given ecological setting characterized by the spatial dynamics of the resource, the two ‘human factors’ of information sharing and management may heterogeneously impact various members of a group for whom theory would otherwise predict the same strategy. When users can deplete the res...
Shifting baselines describes the phenomenon where long-term changes to an environment go unrecogn... more Shifting baselines describes the phenomenon where long-term changes to an environment go unrecognized because what is perceived as natural shifts with succeeding generations of scientists and other observers. This is a particular problem for the oceans because we are rarely able to directly observe the consequences of human activities. In the absence of data to track these consequences, a common assumption has been that the communities we observe today using SCUBA or other technology, are similar to the communities that existed 10, 100, or even 1000 years ago. Research is increasingly demonstrating this is not the case. Instead, marine ecosystems may have been vastly different in the past, and we have succumbed to the shifting baselines syndrome. This has significant implications for scientific study, management, and for human communities more broadly. We discuss these implications, and how we might address the shifting baseline syndrome in the oceans to confront its repercussions. In a world where environmental degradation is accelerating, doing so is critical to avoid further ratcheting down of our expectations of ecosystem health and productivity, and to ensure that we have the information necessary to implement appropriate recovery and management goals.
To implement ecosystem-based approaches to fisheries management, decision makers need insight on ... more To implement ecosystem-based approaches to fisheries management, decision makers need insight on the potential costs and benefits of the policy options available to them. In the Southern Ocean, two such options for addressing trade-offs between krill-dependent predators and the krill fishery include "feedback management" (FBM) strategies and marine protected areas (MPAs); in theory, the first adjusts to change, while the latter is robust to change. We compared two possible FBM options to a proposed MPA in the Antarctic Peninsula and Scotia Sea given a changing climate. One of our feedback options, based on the density of Antarctic krill (Euphasia superba), projected modest increases in the abundances of some populations of krill predators, whereas outcomes from our second FBM option, based on changes in the abundances of penguins, were more mixed, with some areas projecting predator population declines. The MPA resulted in greater increases in some, but not all, predator populations than either feedback strategy. We conclude that these differing outcomes relate to the ways the options separate fishing and predator foraging, either by continually shifting the spatial distribution of fishing away from potentially vulnerable populations (FBM) or by permanently closing areas to fishing (the MPA). For the krill fishery, we show that total catches could be maintained using an FBM approach or slightly increased with the MPA, but the fishery would be forced to adjust fishing locations and sometimes fish in areas of relatively low krill density-both potentially significant costs. Our work demonstrates the potential to shift, rather than avoid, ecological risks and the likely costs of fishing, indicating trade-offs for decision makers to consider.
Global warming has increased the frequency of extreme climate events, yet responses of biological... more Global warming has increased the frequency of extreme climate events, yet responses of biological and human communities are poorly understood, particularly for aquatic ecosystems and fisheries. Retrospective analysis of known outcomes may provide insights into the nature of adaptations and trajectory of subsequent conditions. We consider the 1815 eruption of the Indonesian volcano Tambora and its impact on Gulf of Maine (GoM) coastal and riparian fisheries in 1816. Applying complex adaptive systems theory with historical methods, we analyzed fish export data and contemporary climate records to disclose human and piscine responses to Tambora's extreme weather at different spatial and temporal scales while also considering sociopolitical influences. Results identified a tipping point in GoM fisheries induced by concatenating social and biological responses to extreme weather. Abnormal daily temperatures selectively affected targeted fish species—alewives, shad, herring, and mackerel—according to their migration and spawning phenologies and temperature tolerances. First to arrive, alewives suffered the worst. Crop failure and incipient famine intensified fishing pressure, especially in heavily settled regions where dams already compromised watersheds. Insufficient alewife runs led fishers to target mackerel , the next species appearing in abundance along the coast; thus, 1816 became the " mackerel year. " Critically, the shift from riparian to marine fisheries persisted and expanded after temperatures moderated and alewives recovered. We conclude that contingent human adaptations to extraordinary weather permanently altered this complex system. Understanding how adaptive responses to extreme events can trigger unintended consequences may advance long-term planning for resilience in an uncertain future.
Nonlinear dynamics have been widely demonstrated in natural systems. In marine fisheries ecosyst... more Nonlinear dynamics have been widely demonstrated in natural systems. In marine fisheries ecosystems, such dynamics have primarily been associated with exploited species, suggesting an anthropogenic stressor may explain their prevalence. However, this earlier work com- pared co-occurring exploited and unexploited species, as opposed to analyzing the same species before and after significant harvesting pressure. The former does not control for either differences between species or the reality of indirect and long-lasting fishing impacts. Here, nonlinear dynamics were investigated for the same species before and after significant changes in the magnitude of harvesting. We found nonlinear signatures prevalent prior to heavy industrial exploitation, and also found that these dynamics were highly deterministic. This demonstrates that nonlinearity existed in a complex marine system prior to extensive human influence and suggests such behavior may be an innate property of these populations. Results also show a reduction in deterministic dynamics post industrialization, suggesting that fishing can undermine the dynamics and resilience of marine populations and render fisheries model output less predictable for management.
As a discipline, marine historical ecology (MHE) has contributed significantly to our understandi... more As a discipline, marine historical ecology (MHE) has contributed significantly to our understanding of the past state of the marine environment when levels of human impact were often very different from those today. What is less widely known is that insights from MHE have made headway into being applied within the context of present-day and long-term management and policy. This study draws attention to the applied value of MHE. We demonstrate that a broad knowledge base exists with potential for management application and advice, including the development of baselines and reference levels. Using a number of case studies from around the world, we showcase the value of historical ecology in understanding change and emphasize how it either has already informed management or has the potential to do so soon. We discuss these case studies in a context of the science–policy interface around six themes that are frequently targeted by current marine and maritime policies: climate change, biodiversity conservation, ecosystem structure, habitat integrity, food security, and human governance. We encourage science–policy bodies to actively engage with contributions from MHE, as well-informed policy decisions need to be framed within the context of historical reference points and past resource or ecosystem changes.
Multiple groundfish stocks in New England remain depleted despite management measures that have b... more Multiple groundfish stocks in New England remain depleted despite management measures that have been effective elsewhere. A growing body of research suggests that environmental change driven by increasing concentrations of carbon dioxide in the atmosphere and ocean is unfolding more rapidly in New England than elsewhere, and is an important factor in the failure of these stocks to respond to management. We reviewed research on effects of changes in temperature, salinity, dissolved oxygen, pH, and ocean currents on pelagic life stages, post-settlement life stages, and reproduction of four species in the New England groundfish fishery: Atlantic cod (Gadus morhua), haddock (Melanogrammus aeglefinus), winter flounder (Pseudopleuronectes americanus), and yellowtail flounder (Limanda ferruginea). The volume of research on cod was nearly equal to that on the other three species combined. Similarly, many more studies examined effects of temperature than other factors. The majority of studies suggest adverse outcomes, with less evidence for mixed or positive effects. However, for all of the factors other than temperature, there are more knowledge gaps than known effects. Importantly, most work to date examines impacts in isolation, but effects might combine in nonlinear ways and cause stronger reductions in stock productivity than expected. Management strategies will need to account for known effects, nonlinear interactions, and uncertainties if fisheries in New England are to adapt to environmental change.
Here we summarize presentations given at the theme session "Structure and Function of the Gulf of... more Here we summarize presentations given at the theme session "Structure and Function of the Gulf of Maine System " of the 2009 Gulf of Maine Symposium—Advancing Ecosystem Research for the Future of the Gulf, covering a broad spectrum of multidisciplinary research underway in one of the world's most intensively studied marine systems. Our objective was to attempt a synthesis of the current ecological and oceanographic understanding of the Gulf of Maine and, in particular, to document progress in these areas since the 1996 Gulf of Maine Ecosystem Dynamics Symposium more than a decade earlier. Presentations at the session covered issues ranging from habitat structure and function, biodiversity, population structure, trophic ecology, the intersection of the biological, chemical and physical oceanography of the region, and the dynamics of economically important species. Important strides in characterizing the broader dimensions of biodiversity in the region, the establishment of new sampling programs and the availability of new sensor arrays, and the renewed emphasis synthesis and integration to meet the emerging needs for ecosystem-based management in the gulf have all contributed to a deepened appreciation of its dynamical structure. The critical importance of the ecosystem goods and services provided by the gulf, and the factors affecting the sustainable delivery of these services, was clearly demonstrated in the course of the session. The papers presented at the session made it clear how far we have come and how far we need to go to ensure the sustainable delivery of these services into the future.
ABSTRACT Background/Question/Methods Human exploitation may push system dynamics from equilibrium... more ABSTRACT Background/Question/Methods Human exploitation may push system dynamics from equilibrium to disequilibrium. For example, simple ecological models show populations can go from steady-state to chaotic as a result of increasing intrinsic growth rates. Such a change may result from harvesting, and studies have shown fish populations demonstrate such responses. On the other hand, non-equilibrium dynamics may be part and parcel of natural biological cycles and ecological interactions. Studies of human heart rhythms demonstrate healthy hearts produce signals that are chaotic; such dynamics may help healthy hearts cope with perturbations. Here, we use nonlinear time series forecasting models to classify dynamics as equilibrium or non-equilibrium. Drawing on datasets from a variety of systems, we investigate whether those associated with human exploitation are more likely to exhibit non-equilibrium, nonlinear behavior. Results/Conclusions One example from fisheries, analyzing 145 species from the Pacific and Atlantic oceans, demonstrates that exploited species are far more likely to have non-equilibrium dynamics than unexploited species. A second example from an oak forest in Arkansas demonstrates trees with non-equilibrium dynamics were significantly more likely to survive a wood-boring beetle outbreak, a phenomenon expected to increase under anthropogenic climate change. A third example from mast seeding in plants shows non-equilibrium dynamics may be a natural phenomenon. Finally, a fourth example shows fish populations changed from non-equilibrium dynamics to equilibrium dynamics as fishing pressure increased. These contrasting examples illustrate that patterns are not clearly aligned with human exploitation, and additional biological considerations are important. While non-equilibrium dynamics significantly decrease our ability to make predictions about future behavior, they also may be a coping mechanism for responding to unpredictability of natural systems. Ultimately, non-equilibrium dynamics are not normatively "bad", but it is challenging to determine whether their existence is inherent or a response to human intervention.
Background/Question/Methods Human exploitation may push system dynamics from equilibrium to diseq... more Background/Question/Methods Human exploitation may push system dynamics from equilibrium to disequilibrium. For example, simple ecological models show populations can go from steady-state to chaotic as a result of increasing intrinsic growth rates. Such a change may result from harvesting, and studies have shown fish populations demonstrate such responses. On the other hand, non-equilibrium dynamics may be part and parcel of natural biological cycles and ecological interactions. Studies of human heart rhythms demonstrate healthy hearts produce signals that are chaotic; such dynamics may help healthy hearts cope with perturbations. Here, we use nonlinear time series forecasting models to classify dynamics as equilibrium or non-equilibrium. Drawing on datasets from a variety of systems, we investigate whether those associated with human exploitation are more likely to exhibit non-equilibrium, nonlinear behavior. Results/Conclusions One example from fisheries, analyzing 145 species fro...
Marine environmental history analyses the changing relationships between human societies and mari... more Marine environmental history analyses the changing relationships between human societies and marine natural resources over time. This is the first book which deals in a systematic way with the theoretical backgrounds of this discipline. Major theories and methods are introduced by leading scholars of the field. The book seeks to encapsulate some of the major novelties of this fascinating new discipline and its contribution to the management, conservation and restoration of marine and coastal ecosystems as well as the cultural heritages of coastal communities in different parts of the world.
The ICES Working Group on the History of Fish and Fisheries (WGHIST) is a forum for interdiscipli... more The ICES Working Group on the History of Fish and Fisheries (WGHIST) is a forum for interdisciplinary research on social-ecological change in marine and fisheries systems over multi-decadal to centennial timescales. WGHIST comprises a diverse group of researchers, including marine biologists, fisheries scientists, historians, and historical ecologists, from Europe and North America, as well as Australia, Russia, and South Africa. WGHIST provided a platform for the sharing and reporting of a wide range of research on marine and fisheries systems change over time, including the use of novel and non-traditional data sources and methodologies to identify and interpret these changes. WGHIST members also worked with the ICES Secretariat to forward digital tools to make historical resources more accessible and regarding WGHIST’s potential to support ICES Fisheries and Ecosystem Overviews. WGHIST engaged with the larger research community on the following manuscripts, still in development o...
Both costs and benefits must be considered when implementing marine protected areas (MPAs), parti... more Both costs and benefits must be considered when implementing marine protected areas (MPAs), particularly those associated with fishing effort displaced by potential closures. The Southern Ocean offers a case study in understanding such tradeoffs, where MPAs are actively being discussed to achieve a range of protection and sustainable use objectives. Here, we evaluated the possible impacts of two MPA scenarios on the Antarctic krill (Euphausia superba) fishery and krill-dependent predators in the Scotia Sea, explicitly addressing the displacement of fishing from closed areas. For both scenarios, we employed a minimally realistic, spatially explicit ecosystem model and considered three alternative redistributions of displaced fishing. We projected both MPAs to provide positive outcomes for many krill-dependent predators, especially when closed areas included at least 50-75% of their foraging distributions. Further, differences between the scenarios suggest ways to improve seal and penguin protection in the Scotia Sea. MPA scenarios also projected increases in total fishery yields, but alongside risks of fishing in areas where relatively low krill densities could cause the fishery to suspend operations. The three alternatives for redistributing displaced fishing had little effect on benefits to predators, but did matter for the fishery, with greater differences in overall catch and risk of fishing in areas of low krill density when displaced fishing was redistributed evenly among the open areas. Collectively, results suggest a well-designed MPA in the Scotia Sea may protect krill-dependent predators, even with displaced fishing, and preclude further spatial management of the krill fishery outside the MPA. More broadly, outcomes denote the importance of delineating fishing and predator habitat, spatial scales, and the critical trade-offs inherent in MPA development.
Climate change is a threat to marine ecosystems and the services they provide, and reducing fishi... more Climate change is a threat to marine ecosystems and the services they provide, and reducing fishing pressure is one option for mitigating the overall consequences for marine biota. We used a minimally realistic ecosystem model to examine how projected effects of ocean warming on the growth of Antarctic krill, Euphausia superba, might affect populations of krill and dependent predators (whales, penguins, seals, and fish) in the Scotia Sea. We also investigated the potential to mitigate depletion risk for predators by curtailing krill fishing at different points in the 21st century. The projected effects of ocean warming on krill biomass were strongest in the northern Scotia Sea, with a ≥40% decline in the mass of individual krill. Projections also suggest a 25% chance that krill biomass will fall below an established depletion threshold (75% of its unimpacted level), with consequent risks for some predator populations, especially penguins. Average penguin abundance declined by up to ...
Understanding how and when cooperative human behaviour forms in common-pool resource systems is c... more Understanding how and when cooperative human behaviour forms in common-pool resource systems is critical to illuminating social–ecological systems and designing governance institutions that promote sustainable resource use. Before assessing the full complexity of social dynamics, it is essential to understand, concretely and mechanistically, how resource dynamics and human actions interact to create incentives and pay-offs for social behaviours. Here, we investigated how such incentives for information sharing are affected by spatial dynamics and management in a common-pool resource system. Using interviews with fishermen to inform an agent-based model, we reveal generic mechanisms through which, for a given ecological setting characterized by the spatial dynamics of the resource, the two ‘human factors’ of information sharing and management may heterogeneously impact various members of a group for whom theory would otherwise predict the same strategy. When users can deplete the res...
Shifting baselines describes the phenomenon where long-term changes to an environment go unrecogn... more Shifting baselines describes the phenomenon where long-term changes to an environment go unrecognized because what is perceived as natural shifts with succeeding generations of scientists and other observers. This is a particular problem for the oceans because we are rarely able to directly observe the consequences of human activities. In the absence of data to track these consequences, a common assumption has been that the communities we observe today using SCUBA or other technology, are similar to the communities that existed 10, 100, or even 1000 years ago. Research is increasingly demonstrating this is not the case. Instead, marine ecosystems may have been vastly different in the past, and we have succumbed to the shifting baselines syndrome. This has significant implications for scientific study, management, and for human communities more broadly. We discuss these implications, and how we might address the shifting baseline syndrome in the oceans to confront its repercussions. In a world where environmental degradation is accelerating, doing so is critical to avoid further ratcheting down of our expectations of ecosystem health and productivity, and to ensure that we have the information necessary to implement appropriate recovery and management goals.
To implement ecosystem-based approaches to fisheries management, decision makers need insight on ... more To implement ecosystem-based approaches to fisheries management, decision makers need insight on the potential costs and benefits of the policy options available to them. In the Southern Ocean, two such options for addressing trade-offs between krill-dependent predators and the krill fishery include "feedback management" (FBM) strategies and marine protected areas (MPAs); in theory, the first adjusts to change, while the latter is robust to change. We compared two possible FBM options to a proposed MPA in the Antarctic Peninsula and Scotia Sea given a changing climate. One of our feedback options, based on the density of Antarctic krill (Euphasia superba), projected modest increases in the abundances of some populations of krill predators, whereas outcomes from our second FBM option, based on changes in the abundances of penguins, were more mixed, with some areas projecting predator population declines. The MPA resulted in greater increases in some, but not all, predator populations than either feedback strategy. We conclude that these differing outcomes relate to the ways the options separate fishing and predator foraging, either by continually shifting the spatial distribution of fishing away from potentially vulnerable populations (FBM) or by permanently closing areas to fishing (the MPA). For the krill fishery, we show that total catches could be maintained using an FBM approach or slightly increased with the MPA, but the fishery would be forced to adjust fishing locations and sometimes fish in areas of relatively low krill density-both potentially significant costs. Our work demonstrates the potential to shift, rather than avoid, ecological risks and the likely costs of fishing, indicating trade-offs for decision makers to consider.
Global warming has increased the frequency of extreme climate events, yet responses of biological... more Global warming has increased the frequency of extreme climate events, yet responses of biological and human communities are poorly understood, particularly for aquatic ecosystems and fisheries. Retrospective analysis of known outcomes may provide insights into the nature of adaptations and trajectory of subsequent conditions. We consider the 1815 eruption of the Indonesian volcano Tambora and its impact on Gulf of Maine (GoM) coastal and riparian fisheries in 1816. Applying complex adaptive systems theory with historical methods, we analyzed fish export data and contemporary climate records to disclose human and piscine responses to Tambora's extreme weather at different spatial and temporal scales while also considering sociopolitical influences. Results identified a tipping point in GoM fisheries induced by concatenating social and biological responses to extreme weather. Abnormal daily temperatures selectively affected targeted fish species—alewives, shad, herring, and mackerel—according to their migration and spawning phenologies and temperature tolerances. First to arrive, alewives suffered the worst. Crop failure and incipient famine intensified fishing pressure, especially in heavily settled regions where dams already compromised watersheds. Insufficient alewife runs led fishers to target mackerel , the next species appearing in abundance along the coast; thus, 1816 became the " mackerel year. " Critically, the shift from riparian to marine fisheries persisted and expanded after temperatures moderated and alewives recovered. We conclude that contingent human adaptations to extraordinary weather permanently altered this complex system. Understanding how adaptive responses to extreme events can trigger unintended consequences may advance long-term planning for resilience in an uncertain future.
Nonlinear dynamics have been widely demonstrated in natural systems. In marine fisheries ecosyst... more Nonlinear dynamics have been widely demonstrated in natural systems. In marine fisheries ecosystems, such dynamics have primarily been associated with exploited species, suggesting an anthropogenic stressor may explain their prevalence. However, this earlier work com- pared co-occurring exploited and unexploited species, as opposed to analyzing the same species before and after significant harvesting pressure. The former does not control for either differences between species or the reality of indirect and long-lasting fishing impacts. Here, nonlinear dynamics were investigated for the same species before and after significant changes in the magnitude of harvesting. We found nonlinear signatures prevalent prior to heavy industrial exploitation, and also found that these dynamics were highly deterministic. This demonstrates that nonlinearity existed in a complex marine system prior to extensive human influence and suggests such behavior may be an innate property of these populations. Results also show a reduction in deterministic dynamics post industrialization, suggesting that fishing can undermine the dynamics and resilience of marine populations and render fisheries model output less predictable for management.
As a discipline, marine historical ecology (MHE) has contributed significantly to our understandi... more As a discipline, marine historical ecology (MHE) has contributed significantly to our understanding of the past state of the marine environment when levels of human impact were often very different from those today. What is less widely known is that insights from MHE have made headway into being applied within the context of present-day and long-term management and policy. This study draws attention to the applied value of MHE. We demonstrate that a broad knowledge base exists with potential for management application and advice, including the development of baselines and reference levels. Using a number of case studies from around the world, we showcase the value of historical ecology in understanding change and emphasize how it either has already informed management or has the potential to do so soon. We discuss these case studies in a context of the science–policy interface around six themes that are frequently targeted by current marine and maritime policies: climate change, biodiversity conservation, ecosystem structure, habitat integrity, food security, and human governance. We encourage science–policy bodies to actively engage with contributions from MHE, as well-informed policy decisions need to be framed within the context of historical reference points and past resource or ecosystem changes.
Multiple groundfish stocks in New England remain depleted despite management measures that have b... more Multiple groundfish stocks in New England remain depleted despite management measures that have been effective elsewhere. A growing body of research suggests that environmental change driven by increasing concentrations of carbon dioxide in the atmosphere and ocean is unfolding more rapidly in New England than elsewhere, and is an important factor in the failure of these stocks to respond to management. We reviewed research on effects of changes in temperature, salinity, dissolved oxygen, pH, and ocean currents on pelagic life stages, post-settlement life stages, and reproduction of four species in the New England groundfish fishery: Atlantic cod (Gadus morhua), haddock (Melanogrammus aeglefinus), winter flounder (Pseudopleuronectes americanus), and yellowtail flounder (Limanda ferruginea). The volume of research on cod was nearly equal to that on the other three species combined. Similarly, many more studies examined effects of temperature than other factors. The majority of studies suggest adverse outcomes, with less evidence for mixed or positive effects. However, for all of the factors other than temperature, there are more knowledge gaps than known effects. Importantly, most work to date examines impacts in isolation, but effects might combine in nonlinear ways and cause stronger reductions in stock productivity than expected. Management strategies will need to account for known effects, nonlinear interactions, and uncertainties if fisheries in New England are to adapt to environmental change.
Here we summarize presentations given at the theme session "Structure and Function of the Gulf of... more Here we summarize presentations given at the theme session "Structure and Function of the Gulf of Maine System " of the 2009 Gulf of Maine Symposium—Advancing Ecosystem Research for the Future of the Gulf, covering a broad spectrum of multidisciplinary research underway in one of the world's most intensively studied marine systems. Our objective was to attempt a synthesis of the current ecological and oceanographic understanding of the Gulf of Maine and, in particular, to document progress in these areas since the 1996 Gulf of Maine Ecosystem Dynamics Symposium more than a decade earlier. Presentations at the session covered issues ranging from habitat structure and function, biodiversity, population structure, trophic ecology, the intersection of the biological, chemical and physical oceanography of the region, and the dynamics of economically important species. Important strides in characterizing the broader dimensions of biodiversity in the region, the establishment of new sampling programs and the availability of new sensor arrays, and the renewed emphasis synthesis and integration to meet the emerging needs for ecosystem-based management in the gulf have all contributed to a deepened appreciation of its dynamical structure. The critical importance of the ecosystem goods and services provided by the gulf, and the factors affecting the sustainable delivery of these services, was clearly demonstrated in the course of the session. The papers presented at the session made it clear how far we have come and how far we need to go to ensure the sustainable delivery of these services into the future.
ABSTRACT Background/Question/Methods Human exploitation may push system dynamics from equilibrium... more ABSTRACT Background/Question/Methods Human exploitation may push system dynamics from equilibrium to disequilibrium. For example, simple ecological models show populations can go from steady-state to chaotic as a result of increasing intrinsic growth rates. Such a change may result from harvesting, and studies have shown fish populations demonstrate such responses. On the other hand, non-equilibrium dynamics may be part and parcel of natural biological cycles and ecological interactions. Studies of human heart rhythms demonstrate healthy hearts produce signals that are chaotic; such dynamics may help healthy hearts cope with perturbations. Here, we use nonlinear time series forecasting models to classify dynamics as equilibrium or non-equilibrium. Drawing on datasets from a variety of systems, we investigate whether those associated with human exploitation are more likely to exhibit non-equilibrium, nonlinear behavior. Results/Conclusions One example from fisheries, analyzing 145 species from the Pacific and Atlantic oceans, demonstrates that exploited species are far more likely to have non-equilibrium dynamics than unexploited species. A second example from an oak forest in Arkansas demonstrates trees with non-equilibrium dynamics were significantly more likely to survive a wood-boring beetle outbreak, a phenomenon expected to increase under anthropogenic climate change. A third example from mast seeding in plants shows non-equilibrium dynamics may be a natural phenomenon. Finally, a fourth example shows fish populations changed from non-equilibrium dynamics to equilibrium dynamics as fishing pressure increased. These contrasting examples illustrate that patterns are not clearly aligned with human exploitation, and additional biological considerations are important. While non-equilibrium dynamics significantly decrease our ability to make predictions about future behavior, they also may be a coping mechanism for responding to unpredictability of natural systems. Ultimately, non-equilibrium dynamics are not normatively "bad", but it is challenging to determine whether their existence is inherent or a response to human intervention.
Background/Question/Methods Human exploitation may push system dynamics from equilibrium to diseq... more Background/Question/Methods Human exploitation may push system dynamics from equilibrium to disequilibrium. For example, simple ecological models show populations can go from steady-state to chaotic as a result of increasing intrinsic growth rates. Such a change may result from harvesting, and studies have shown fish populations demonstrate such responses. On the other hand, non-equilibrium dynamics may be part and parcel of natural biological cycles and ecological interactions. Studies of human heart rhythms demonstrate healthy hearts produce signals that are chaotic; such dynamics may help healthy hearts cope with perturbations. Here, we use nonlinear time series forecasting models to classify dynamics as equilibrium or non-equilibrium. Drawing on datasets from a variety of systems, we investigate whether those associated with human exploitation are more likely to exhibit non-equilibrium, nonlinear behavior. Results/Conclusions One example from fisheries, analyzing 145 species fro...
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pared co-occurring exploited and unexploited species, as opposed to analyzing the same species before and after significant harvesting pressure. The former does not control for either differences between species or the reality of indirect and long-lasting fishing impacts. Here, nonlinear dynamics were investigated for the same species before and after significant changes in the magnitude of harvesting. We found nonlinear signatures prevalent prior to heavy industrial exploitation, and also found that these dynamics were highly deterministic. This demonstrates that nonlinearity existed in a complex marine system prior to extensive human influence and suggests such behavior may be an innate property of these populations. Results also show a reduction in deterministic dynamics post industrialization, suggesting that fishing can undermine the dynamics and resilience of marine populations and render fisheries model output less predictable for management.
morhua), haddock (Melanogrammus aeglefinus), winter flounder (Pseudopleuronectes americanus), and yellowtail flounder (Limanda ferruginea). The volume of research on cod was nearly equal to that on the other three species combined. Similarly, many more studies
examined effects of temperature than other factors. The majority of studies suggest adverse outcomes, with less evidence for mixed or positive effects. However, for all of the factors other than temperature, there are more knowledge gaps than known effects. Importantly, most
work to date examines impacts in isolation, but effects might combine in nonlinear ways and cause stronger reductions in stock productivity than expected. Management strategies will need to account for known
effects, nonlinear interactions, and uncertainties if fisheries in New England are to adapt to environmental change.
pared co-occurring exploited and unexploited species, as opposed to analyzing the same species before and after significant harvesting pressure. The former does not control for either differences between species or the reality of indirect and long-lasting fishing impacts. Here, nonlinear dynamics were investigated for the same species before and after significant changes in the magnitude of harvesting. We found nonlinear signatures prevalent prior to heavy industrial exploitation, and also found that these dynamics were highly deterministic. This demonstrates that nonlinearity existed in a complex marine system prior to extensive human influence and suggests such behavior may be an innate property of these populations. Results also show a reduction in deterministic dynamics post industrialization, suggesting that fishing can undermine the dynamics and resilience of marine populations and render fisheries model output less predictable for management.
morhua), haddock (Melanogrammus aeglefinus), winter flounder (Pseudopleuronectes americanus), and yellowtail flounder (Limanda ferruginea). The volume of research on cod was nearly equal to that on the other three species combined. Similarly, many more studies
examined effects of temperature than other factors. The majority of studies suggest adverse outcomes, with less evidence for mixed or positive effects. However, for all of the factors other than temperature, there are more knowledge gaps than known effects. Importantly, most
work to date examines impacts in isolation, but effects might combine in nonlinear ways and cause stronger reductions in stock productivity than expected. Management strategies will need to account for known
effects, nonlinear interactions, and uncertainties if fisheries in New England are to adapt to environmental change.