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The world's eastern boundary upwelling systems (EBUSs) contribute disproportionately to global ocean productivity and provide critical ecosystem services to human society. The impact of climate change on EBUSs and the ecosystems they support is thus a subject of considerable interest. Here, we review hypotheses of climate-driven change in the physics, biogeochemistry, and ecology of EBUSs; describe observed changes over recent decades; and present projected changes over the twenty-first century. Similarities in historical and projected change among EBUSs include a trend toward upwelling intensification in poleward regions, mitigated warming in near-coastal regions where upwelling intensifies, and enhanced water-column stratification and a shoaling mixed layer. However, there remains significant uncertainty in how EBUSs will evolve with climate change, particularly in how the sometimes competing changes in upwelling intensity, source-water chemistry, and stratification will affect productivity and ecosystem structure. We summarize the commonalities and differences in historical and projected change in EBUSs and conclude with an assessment of key remaining uncertainties and questions. Future studies will need to address these questions to better understand, project, and adapt to climate-driven changes in EBUSs. Expected final online publication date for the

Interannual and regime (decadal) scale changes in climate affect the spatial distribution and productivity of marine fish species in numerous ecosystems. We analyzed a historical simulation (1965-2000) from an end-to-end ecosystem model of anchovy population dynamics for the California Current System to untangle the effects of warm versus cool conditions on recruitment. A�3-dimensional coupled hydrodynamic-NPZD (nitrogen-phytoplankton-zooplankton-detritus) model (ROMS-NEMURO) provided the physical conditions (circulation, temperature) and 3 zooplankton concentrations as inputs to an anchovy full life cycle individual-based model (IBM). Our analysis was focused on isolating the effects of the well-documented El Niño Southern Oscillation signal and 3 climate regimes on spawning habitat, development, and survival of eggs and yolk-sac larvae, growth and survival of larvae and juveniles, and ultimately recruitment of anchovy. The major drivers of lowered recruitment success in warm years and in warmer regimes were reduced survival and growth rates of eggs and larvae that resulted from the poleward shift of adults in response to warmer temperatures prior to spawning. Three model-data comparisons showed the model deviated from empirically derived values of annual recruitment success but agreed with data for annual mean latitude of egg distributions and predicted larval consumption rates versus measured zooplankton concentrations. More effort is needed to improve certain biological aspects of the IBM so that it can replicate empirically estimated recruitment fluctuations. Overall, the altered responses of anchovy to changing climate in the California Current domain illustrate the benefit of the present mechanistic approach to infer how anchovy may respond under future ecosystem conditions.

This perspective paper discusses how the research community can promote enhancement of marine ecosystem forecasts using physical ocean conditions predicted by global climate models (GCMs). We review the major climate prediction projects and outline new research opportunities to achieve skillful marine biological forecasts. Physical ocean conditions are operationally predicted for subseasonal to seasonal timescales, and multi-year predictions have been enhanced recently. However, forecasting applications are currently limited by the availability of oceanic data; most subseasonal-to-seasonal prediction projects make only sea-surface temperature (SST) publicly available, though other variables useful for biological forecasts are also calculated in GCMs. To resolve the bottleneck of data availability, we recommend that climate prediction centers increase the range of ocean data available to the public, perhaps starting with an expanded suite of 2-dimensional variables, whose storage requirements are much smaller than 3-dimensional variables. Allowing forecast output to be downloaded for a selected region, rather than the whole globe, would also facilitate uptake. We highlight new research opportunities in both physical forecasting (e.g., new approaches to dynamical and statistical downscaling) and biological forecasting (e.g., conducting biological reforecasting experiments) and offer lessons learned to help guide their development. In order to accelerate this research area, we also suggest establishing case studies (i.e., particular climate and biological events as prediction targets) to improve coordination. Advancing our capacity for marine biological forecasting is crucial for the success of the UN Decade of Ocean Science, for which one of seven desired outcomes is “A Predicted Ocean”.

Ocean memory, the persistence of ocean conditions, is a major source of predictability in the climate system beyond weather time scales. We show that ocean memory, as measured by the year-to-year persistence of sea surface temperature anomalies, is projected to steadily decline in the coming decades over much of the globe. This global decline in ocean memory is predominantly driven by shoaling of the upper-ocean mixed layer depth in response to global surface warming, while thermodynamic and dynamic feedbacks can contribute substantially regionally. As the mixed layer depth shoals, stochastic forcing becomes more effective in driving sea surface temperature anomalies, increasing high-frequency noise at the expense of persistent signals. Reduced ocean memory results in shorter lead times of skillful persistence-based predictions of sea surface thermal conditions, which may present previously unknown challenges for predicting climate extremes and managing marine biological resources under climate change.

Transfer efficiency is the proportion of energy passed between nodes in food webs. It is an emergent, unitless property that is difficult to measure, and responds dynamically to environmental and ecosystem changes. Because the consequences of changes in transfer efficiency compound through ecosystems, slight variations can have large effects on food availability for top predators. Here, we review the processes controlling transfer efficiency, approaches to estimate it, and known variations across ocean biomes. Both process-level analysis and observed macroscale variations suggest that ecosystem-scale transfer efficiency is highly variable, impacted by fishing, and will decline with climate change. It is important that we more fully resolve the processes controlling transfer efficiency in models to effectively anticipate changes in marine ecosystems and fisheries resources.

Wind-induced mixing can affect the vertical distribution of plankton in the upper water column, influencing the prey available for larval fishes. The stable ocean hypothesis proposes that periods of calm winds facilitate the development of plankton layers at concentrations sufficient for successful larval foraging and increased survival. Conversely, storm events redistribute prey, leading to reduced foraging success. Here, we investigate this hypothesis by comparing larval fish mortality rates estimated from 37 years of ichthyoplankton data against metrics of wind events defined as storms and calm periods. Contrary to expectations, we found that mortality for Pacific hake (Merluccius productus) significantly decreased as storm events increased in the southern California Current Ecosystem. Mortality rates for northern anchovy (Engraulis mordax), Pacific sardine (Sardinops sagax), Pacific mackerel (Scomber japonicus), and jack mackerel (Trachurus symmetricus) had no relationship to storms, and no species’ mortality rates were related to the number of calm events. Our results highlight the differing sensitivities of larval survival among fishes in the region and indicate that responses to atmospheric processes are species-dependent.

Massive populations of sardines inhabit both the western and eastern boundaries of the world’s subtropical ocean basins, supporting both commercial fisheries and populations of marine predators. Sardine populations in western and eastern boundary current systems have responded oppositely to decadal scale anomalies in ocean temperature, but the mechanism for differing variability has remained unclear. Here, based on otolith microstructure and high-resolution stable isotope analyses, we show that habitat temperature, early life growth rates, energy expenditure, metabolically optimal temperature, and, most importantly, the relationship between growth rate and temperature are remarkably different between the two subpopulations in the western and eastern North Pacific. Varying metabolic responses to environmental changes partly explain the contrasting growth responses. Consistent differences in the life-history traits are observed between subpopulations in the western and eastern boundary current systems around South Africa. These growth and survival characteristics can facilitate the contrasting responses of sardine populations to climate change., 大洋の東西で異なるマイワシの環境応答 --耳石が示すグローバル生存戦略の鍵--. 京都大学プレスリリース. 2022-10-17.

Given the ecological and economic importance of eastern boundary upwelling systems like the California Current System (CCS), their evolution under climate change is of considerable interest for resource management. However, the spatial resolution of global earth system models (ESMs) is typically too coarse to properly resolve coastal winds and upwelling dynamics that are key to structuring these ecosystems. Here we use a high-resolution (0.1°) regional ocean circulation model coupled with a biogeochemical model to dynamically downscale ESMs and produce climate projections for the CCS under the high emission scenario, Representative Concentration Pathway 8.5. To capture model uncertainty in the projections, we downscale three ESMs: GFDL-ESM2M, HadGEM2-ES, and IPSL-CM5A-MR, which span the CMIP5 range for future changes in both the mean and variance of physical and biogeochemical CCS properties. The forcing of the regional ocean model is constructed with a “time-varying delta” method, which removes the mean bias of the ESM forcing and resolves the full transient ocean response from 1980 to 2100. We found that all models agree in the direction of the future change in offshore waters: an intensification of upwelling favorable winds in the northern CCS, an overall surface warming, and an enrichment of nitrate and corresponding decrease in dissolved oxygen below the surface mixed layer. However, differences in projections of these properties arise in the coastal region, producing different responses of the future biogeochemical variables. Two of the models display an increase of surface chlorophyll in the northern CCS, consistent with a combination of higher nitrate content in source waters and an intensification of upwelling favorable winds. All three models display a decrease of chlorophyll in the southern CCS, which appears to be driven by decreased upwelling favorable winds and enhanced stratification, and, for the HadGEM2-ES forced run, decreased nitrate content in upwelling source waters in nearshore regions. While trends in the downscaled models reflect those in the ESMs that force them, the ESM and downscaled solutions differ more for biogeochemical than for physical variables.

Changes in the abundance and productivity of biological populations in the North Pacific have often been associated with large-scale modes of climate variability. The Pacific Decadal Oscillation (PDO), which describes spatio-temporal variability in North Pacific sea surface temperature (SST), correlates with much of this variability. However, since the late 1980s, the North Pacific Gyre Oscillation (NPGO) has explained an increasing proportion of variance in North Pacific climate properties. Ecological responses to this change in the proportion of variance ascribed to the two climate patterns remain poorly understood. Here, we test the hypothesis that relationships between biological time series and climate covariates (SST and the PDO) differ for nine Gulf of Alaska fish and crustacean populations before and after the late 1980s. Additionally, we evaluate whether non-stationary climate-biology relationships arose synchronously across populations as a community response. We used different formulations of Generalized Additive Models in a population and community context and compared results to the classical approach of aggregated population responses based on Principal Component Analysis (PCA). The results showed that climate-biology relationships weakened or reversed for most populations in the late 1980s, coinciding with the increase in variance of the NPGO. However, these non-stationary responses were highly species-specific and did not arise synchronously as a community response. We show that PCA does not represent community dynamics properly when only few species covary in time and exhibit long-term trends. Therefore, this approach might not be always useful to detect synchronous changes among biological time series as a community response. Novel associations among climate variables and novel climate-biology relationships are expected to become increasingly evident with future climate change, and the recognition of switches between different explanatory variable-response relationships may be critical for successful management of marine resources during transitions to these novel climate states.

The California Current System (CCS) has two independent seasonal modes of upwelling variability, summer and winter, driven by different atmospheric processes. The variability of upwelling winds during winter is particularly important as strong, episodic events, driven by atmospheric teleconnections with the equatorial Pacific that are active in this season, impact ecological systems along the west coast of North America. Given the importance of upwelling seasonality to ecosystem function, we hypothesize that the Benguela Current System (BCS) shows similar independent seasonal modes of upwelling variability. To test this hypothesis, compare modes of variability between systems, and investigate potential drivers, we use an upwelling index derived from NCEP2 wind data (1979–2014) for the northern, southern, and Agulhas Bank areas of the BCS. In the northern and southern BCS, only one mode of upwelling variability is observed: year-round in the north and during the austral spring and summer (October through April) in the south. The Agulhas Bank region shows two modes of seasonal variability. Based on this 35-year dataset, summer upwelling modes in both the CCS and BCS appear to have similar decadal-scale variability. The other modes of variability (winter mode in the CCS and the non-seasonal second mode in the BCS) are correlated with year-to-year variability in the positioning of regional oceanic high-pressure systems. The leading mode of upwelling variability in the Agulhas Bank region, in the austral summer/fall, is highly correlated with sea level pressure as well as sea surface temperature in the equatorial Pacific, in a spatial and seasonal pattern (boreal winter) resembling the El Nino-Southern Oscillation. Across the CCS, modes of upwelling variability are similar to one another, while modes differ between regions in the BCS. This difference could lead to regional mismatches in favorable ecological conditions. In contrast with the spatially synchronous winter variability influencing the entire CCS ecosystem, substantial regional variation in the BCS may have strong effects on ecosystem functions, especially for species (e.g., small pelagic fish) that migrate between the Agulhas Bank and other areas of the BCS.

The present review is an outcome of discussions at the ICES-PICES Symposium on Drivers of Dynamics of Small Pelagic Fish convened in Victoria, B.C., Canada in spring 2017.-- This review is a first contribution of a new international Working Group on Small Pelagic Fish started jointly by ICES (WGSPF) and PICES (WG43) to continue world-wide collaboration to advance knowledge on the drivers of populations of SPF., Small pelagic fish (SPF) play extremely important ecological roles in marine ecosystems, form some of the most economically valuable fisheries resources, and play a vital role in global food security. Due to their short generation times and tight coupling to lower trophic levels, populations of SPF display large boom-and-bust dynamics that are closely linked to climate variability. To reveal emerging global research trends on SPF as opposed to more recently published, ecosystem-specific reviews of SPF, we reviewed the literature published in two, 6-year periods in the new millennium (2001–2006, and 2011–2016) straddling the publication of a large, global review of the dynamics of SPF in 2009. We explored intrinsic and extrinsic (bottom-up) factors influencing the dynamics of SPF such as anchovies, sardines, herrings and sprats within the sub-order Clupeidae. Published research efforts within 16 different biogeographic ocean regions were compiled (more than 900 studies) and compared to identify i) new milestones and advances in our understanding, ii) emerging research trends and iii) remaining gaps in knowledge. Studies were separated into 5 categories (field, laboratory, mesocosms, long-term statistical analyses and spatially-explicit modelling) and discussed in relation to 10 bottom-up categories including 5 abiotic factors (temperature, salinity, pH, dissolved oxygen, density), 3 physical processes (advection, turbulence, turbidity) and 2 biotic factors (prey quantity and quality). The peer-reviewed literature reflects changes in the number of studies between the two time periods including increases (Mediterranean Sea, Humboldt Current) and decreases (Australia, Benguela Current). Our review highlights i) gaps in ecological knowledge on young juveniles and, in general, on the impacts of hypoxia and heatwaves on SPF, ii) the utility of paleo studies in exploring population drivers, iii) the continued need to develop spatially-explicit, full life-cycle models, iv) the importance of exploring how density-dependent processes impact vital rates (growth, survival, reproduction), and v) the benefits of international collaboration for knowledge transfer and building unifying hypotheses on the role of bottom-up factors and processes that regulate SPF populations., MAP received partial funding from ‘PANDORA’ (Paradigm for New Dynamic Ocean Resource Assessments and Exploitation, (EU H2020, No. 773713).

Upwelling in the California Current System (CCS) sustains a productive ecosystem and is mediated by alongshore, equatorward wind stress. A decades-old hypothesis proposes that global warming will accelerate these upwelling-favorable winds. Recent analyses provide empirical support for upwelling intensification in the poleward portion of the CCS. However, these studies rely on proxies for upwelling and are limited in their ability to distinguish anthropogenic forcing from internal climate variability. Here, we estimate simulated changes in CCS upwelling from 1920 to 2100 using monthly output from a single climate model ensemble, where divergences among simulations can be attributed entirely to internal climate variability. Our projections suggest that CCS upwelling will become more intense in the spring and less intense in the summer as a result of anthropogenic climate change. Anthropogenic changes in upwelling will emerge primarily in the second half of the century.

Anchovy and sardine populated productive ocean regions over hundreds of thousands of years under a naturally varying climate, and are now subject to climate change of equal or greater magnitude occurring over decades to centuries. We hypothesize that anchovy and sardine populations are limited in size by the supply of nitrogen from outside their habitats originating from upwelling, mixing, and rivers. Projections of the responses of anchovy and sardine to climate change rely on a range of model types and consideration of the effects of climate on lower trophic levels, the effects of fishing on higher trophic levels, and the traits of these two types of fish. Distribution, phenology, nutrient supply, plankton composition and production, habitat compression, fishing, and acclimation and adaptation may be affected by ocean warming, acidification, deoxygenation, and altered hydrology. Observations of populations and evaluation of model skill are essential to resolve the effects of climate change on these fish.

Common approaches for summarizing multivariate environmental or community data assume that relationships among variables are stationary over time, and this assumption is often not tested. Here we test the hypothesis that relationships among environmental and community time series are nonstationary in the Gulf of Alaska ecosystem (North Pacific Ocean) over multidecadal time scales. Dynamic factor analysis (DFA) is applied to environmental and community data from before and after 1988/1989, corresponding to the timing of an abrupt decline in temporal variance of the Aleutian Low atmospheric pattern, a leading driver of Gulf of Alaska climate. Results show that covariance among local atmosphere and ocean environmental variables weakened simultaneous to the decline in Aleutian Low variance. At the same time, community-wide responses of 14 fish and crustacean populations to physical forcing weakened, as indicated by nonstationary environment–biology regression coefficients. In line with theoretical predictions, this loss of a shared response to environmental variability was accompanied by weakening community covariance. Individual populations also showed nonstationary relationships with shared trends of community variability. We conclude that assumptions of fixed environmental and community relationships are likely to produce mistaken inference in this ecosystem. Similar concerns may apply in other ecosystems subject to changing climate patterns

“Forecasting and Understanding Trends, Uncertainty and Responses of North Pacific Marine Ecosystems” (FUTURE) is the flagship integrative Scientific Program undertaken by the member nations and affiliates of the North Pacific Marine Science Organization (PICES). A principal goal of FUTURE is to develop a framework for investigating interactions across disciplinary dimensions in order to most effectively understand large-scale ecosystem changes and resulting impacts on coastal communities. These interactions are complex, often nonlinear, occur across a range of spatial and temporal scales, and can complicate management approaches to shared and trans-boundary problems. Here, we present a Social–Ecological–Environmental Systems (SEES) framework to coordinate and integrate marine science within PICES. We demonstrate the application of this framework by applying it to four “crisis” case studies: (a) species alternation in the western North Pacific; (b) ecosystem impacts of an extreme heat wave in the eastern North Pacific; (c) jellyfish blooms in the western North Pacific; and (d) Pacific basin-scale warming and species distributional shifts. Our approach fosters a common transdisciplinary language and knowledge base across diverse expertise, providing the basis for developing better integrated end-to-end models. PICES provides the structure required to address these and other multi-national, inter-disciplinary issues we face in the North Pacific. An effective and comprehensive SEES approach is broadly applicable to understanding and maintaining resilient marine ecosystems within a changing climate.

Marine ecosystem forecasting is an area of active research and rapid development. Promise has been shown for skillful prediction of physical, biogeochemical, and ecological variables on a range of timescales, suggesting potential for forecasts to aid in the management of living marine resources and coastal communities. However, the mechanisms underlying forecast skill in marine ecosystems are often poorly understood, and many forecasts, especially for biological variables, rely on empirical statistical relationships developed from historical observations. Here, we review statistical and dynamical marine ecosystem forecasting methods and highlight examples of their application along U.S. coastlines for seasonal-to-interannual (1–24 month) prediction of properties ranging from coastal sea level to marine top predator distributions. We then describe known mechanisms governing marine ecosystem predictability and how they have been used in forecasts to date. These mechanisms include physical atmospheric and oceanic processes, biogeochemical and ecological responses to physical forcing, and intrinsic characteristics of species themselves. In reviewing the state of the knowledge on forecasting techniques and mechanisms underlying marine ecosystem predictability, we aim to facilitate forecast development and uptake by (i) identifying methods and processes that can be exploited for development of skillful regional forecasts, (ii) informing priorities for forecast development and verification, and (iii) improving understanding of conditional forecast skill (i.e., a priori knowledge of whether a forecast is likely to be skillful). While we focus primarily on coastal marine ecosystems surrounding North America (and the U.S. in particular), we detail forecast methods, physical and biological mechanisms, and priority developments that are globally relevant.

Studies of climate effects on ecology often account for non-stationarity in individual physical and biological variables, but rarely allow for non-stationary relationships among variables. Here, we show that non-stationary relationships among physical and biological variables are central to understanding climate effects on salmon ( Onchorynchus spp.) in the Gulf of Alaska during 1965–2012. The relative importance of two leading patterns in North Pacific climate, the Pacific Decadal Oscillation (PDO) and North Pacific Gyre Oscillation (NPGO), changed around 1988/1989 as reflected by changing correlations with leading axes of sea surface temperature variability. Simultaneously, relationships between the PDO and Gulf of Alaska environmental variables weakened, and long-standing temperature–salmon and PDO–salmon covariance declined to zero. We propose a mechanistic explanation for changing climate–salmon relationships in terms of non-stationary atmosphere–ocean interactions coinciding with changing PDO–NPGO relative importance. We also show that regression models assuming stationary climate–salmon relationships are inappropriate over the multidecadal time scale we consider. Relaxing assumptions of stationary relationships markedly improved modelling of climate effects on salmon catches and productivity. Attempts to understand the implications of changing climate patterns in other ecosystems might also be aided by the application of models that allow associations among environmental and biological variables to change over time.

Upwelling is critical to the biological production, acidification, and deoxygenation of the ocean's major eastern boundary current ecosystems. A leading conceptual hypothesis projects that the winds that induce coastal upwelling will intensify in response to increased land-sea temperature differences associated with anthropogenic global warming. We examine this hypothesis using an ensemble of coupled, ocean-atmosphere models and find limited evidence for intensification of upwelling-favorable winds or atmospheric pressure gradients in response to increasing land-sea temperature differences. However, our analyses reveal consistent latitudinal and seasonal dependencies of projected changes in wind intensity associated with poleward migration of major atmospheric high-pressure cells. Summertime winds near poleward boundaries of climatological upwelling zones are projected to intensify, while winds near equatorward boundaries are projected to weaken. Developing a better understanding of future changes in upwelling winds is essential to identifying portions of the oceans susceptible to increased hypoxia, ocean acidification, and eutrophication under climate change.

Ecosystem productivity in coastal ocean upwelling systems is threatened by climate change. Increases in spring and summer upwelling intensity, and associated increases in the rate of offshore advection, are expected. While this could counter effects of habitat warming, it could also lead to more frequent hypoxic events and lower densities of suitable-sized food particles for fish larvae. With upwelling intensification, ocean acidity will rise, affecting organisms with carbonate structures. Regardless of changes in upwelling, near-surface stratification, turbulent diffusion rates, source water origins, and perhaps thermocline depths associated with large-scale climate episodes (ENSO) maybe affected. Major impacts on pelagic fish resources appear unlikely unless couples with overfishing, although changes toward more subtropical community composition are likely. Marine mammals and seabirds that are tied to sparsely distributed nesting or resting grounds could experience difficulties in obtaining prey resources, or adaptively respond by moving to more favorable biogeographic provinces.

Eastern Pacific populations of the leatherback turtle (Dermochelys coriacea) have declined by over 90% during the past three decades. The decline is primarily attributed to human pressures, including unsustainable egg harvest, development on nesting beaches, and by-catch mortality. In particular, the effects of climate change may impose additional stresses upon already threatened leatherback populations. This study analyzes how the pelagic habitat of Eastern Pacific leatherbacks may be affected by climate change over the next century. This population adheres to a persistent migration pattern; following nesting at Playa Grande, Costa Rica, individuals move rapidly through equatorial currents and into foraging habitat within the oligotrophic South Pacific Gyre. Forty-six nesting females were fitted with satellite tags. Based on the turtle positions, ten environmental variables were sampled along the tracks. Presence/absence habitat models were created to determine the oceanographic characteristics of the preferred turtle habitat. Core pelagic habitat was characterized by relatively low sea surface temperatures and chlorophyll-a. Based on these habitat models, we predicted habitat change using output from the Geophysical Fluid Dynamics Laboratory prototype Earth System Model under the Special Report on Emissions Scenario A2 (business-as-usual). Although the model predicted both habitat losses and gains throughout the region, we estimated that overall the core pelagic habitat of the Eastern Pacific leatherback population will decline by approximately 15% within the next century. This habitat modification might increase pressure on a critically endangered population, possibly forcing distributional shifts, behavioral changes, or even extinction.

Along the western margin of North America, the winter expression of the North Pacific High (NPH) strongly influences interannual variability in coastal upwelling, storm track position, precipitation, and river discharge. Coherence among these factors induces covariance among physical and biological processes across adjacent marine and terrestrial ecosystems. Here, we show that over the past century the degree and spatial extent of this covariance (synchrony) has substantially increased, and is coincident with rising variance in the winter NPH. Furthermore, centuries-long blue oak (Quercus douglasii) growth chronologies sensitive to the winter NPH provide robust evidence that modern levels of synchrony are among the highest observed in the context of the last 250 years. These trends may ultimately be linked to changing impacts of the El Nino Southern Oscillation on midlatitude ecosystems of North America. Such a rise in synchrony may destabilize ecosystems, expose populations to higher risks of extinction, and is thus a concern given the broad biological relevance of winter climate to biological systems.

Recent developments in global dynamical climate prediction systems have allowed for skillful predictions of climate variables relevant to living marine resources (LMRs) at a scale useful to understanding and managing LMRs. Such predictions present opportunities for improved LMR management and industry operations, as well as new research avenues in fisheries science. LMRs respond to climate variability via changes in physiology and behavior. For species and systems where climate-fisheries links are well established, forecasted LMR responses can lead to anticipatory and more effective decisions, benefitting both managers and stakeholders. Here, we provide an overview of climate prediction systems and advances in seasonal to decadal prediction of marine-resource relevant environmental variables. We then describe a range of climate-sensitive LMR decisions that can be taken at lead-times of months to decades, before highlighting a range of pioneering case studies using climate predictions to inform LMR decisions. The success of these case studies suggests that many additional applications are possible. Progress, however, is limited by observational and modeling challenges. Priority developments include strengthening of the mechanistic linkages between climate and marine resource responses, development of LMR models able to explicitly represent such responses, integration of climate driven LMR dynamics in the multi-driver context within which marine resources exist, and improved prediction of ecosystem-relevant variables at the fine regional scales at which most marine resource decisions are made. While there are fundamental limits to predictability, continued advances in these areas have considerable potential to make LMR managers and industry decision more resilient to climate variability and help sustain valuable resources. Concerted dialog between scientists, LMR managers and industry is essential to realizing this potential.

Photosynthesis fuels marine food webs, yet differences in fish catch across globally distributed marine ecosystems far exceed differences in net primary production (NPP). We consider the hypothesis that ecosystem-level variations in pelagic and benthic energy flows from phytoplankton to fish, trophic transfer efficiencies, and fishing effort can quantitatively reconcile this contrast in an energetically consistent manner. To test this hypothesis, we enlist global fish catch data that include previously neglected contributions from small-scale fisheries, a synthesis of global fishing effort, and plankton food web energy flux estimates from a prototype high-resolution global earth system model (ESM). After removing a small number of lightly fished ecosystems, stark interregional differences in fish catch per unit area can be explained (r = 0.79) with an energy-based model that (i) considers dynamic interregional differences in benthic and pelagic energy pathways connecting phytoplankton and fish, (ii) depresses trophic transfer efficiencies in the tropics and, less critically, (iii) associates elevated trophic transfer efficiencies with benthic-predominant systems. Model catch estimates are generally within a factor of 2 of values spanning two orders of magnitude. Climate change projections show that the same macroecological patterns explaining dramatic regional catch differences in the contemporary ocean amplify catch trends, producing changes that may exceed 50% in some regions by the end of the 21st century under high-emissions scenarios. Models failing to resolve these trophodynamic patterns may significantly underestimate regional fisheries catch trends and hinder adaptation to climate change.

Rings of ocean upwelling Coastal upwelling along the coast of California has become more variable than during nearly any period in the past 600 years. Black et al. used a 576-year tree ring record to construct a record of wintertime climate along the California coast. Because wintertime climate and coastal upwelling are so closely linked there, they were able to determine that upwelling variability has increased more over the past 60 years than for all but two intervals during that time. The apparent causes of the recent trend appear to be unique, resulting in reduced marine productivity and negative impacts on fish, seabirds, and mammals. Science , this issue p. 1498

Strong winds, upwelling, and teeming shores Climate warming has produced stronger winds along some coasts, a result of growing differences in temperature and pressure between land and sea. These winds cause cold nutrient-rich seawater to rise to the surface, affecting climate and fueling marine productivity. Sydeman et al. examined data from the five major world regions where upwelling is occurring. Particularly in the California, Humboldt, and Benguela upwelling systems, winds have become stronger over the past 60 years. These regions represent up to a fifth of wild marine fish catches and are hot spots of biodiversity. Science , this issue p. 77

Understanding the mechanisms driving fisheries production is essential if we are to accurately predict changes under climate change and exploit fish stocks in a sustainable manner. Traditionally, studies have sought to distinguish between the two most prominent drivers, ‘bottom-up’ (resource driven) and ‘top-down’ (consumer driven); however, this dichotomy is increasingly proving to be artificial as the relative importance of each mechanism has been shown to vary through space and time. Nevertheless, the reason why one predominates over another within a region remains largely unknown. To address this gap in understanding, we identified the dominant driver of commercial landings within 47 ecosystems, encompassing a wide range of biogeochemical conditions and fishing practices to elucidate general patterns. We show that bottom-up and top-down effects vary consistently with past fishing pressure and oceanographic conditions; bottom-up control predominates within productive, overfished regions and top-down in relatively unproductive and under-exploited areas. We attribute these findings to differences in the species composition and oceanographic properties of regions, together with variation in fishing practices and (indicative) management effectiveness. Collectively, our analyses suggest that despite the complexity of ecological systems, it is possible to elucidate a number of generalities. Such knowledge could be used to increase the parsimony of ecosystem models and to move a step forward in predicting how the global ocean, particularly fisheries productivity, will respond to climate change.

[1] We use the 20th Century Reanalysis database to assess the influence of oceanic and terrestrial atmospheric pressure systems on winter and summer upwelling-favorable winds in Eastern Boundary Upwelling Systems. The analysis provides baseline information regarding the roles of continental thermal low (CTL) and oceanic high (OH) pressure systems in driving seasonal upwelling modes, which have high biological relevance. We show that variability in upwelling-favorable winds is dominated by OH, particularly in winter, and only weakly influenced by CTL, except at annual time scales. This is most pronounced in the California system given that the North Pacific High dominates wind variability. In contrast, CTL and OH equally influence Benguela upwelling-favorable winds during summer. This work underscores the need to understand how OH systems are likely to respond to climate change and how this might impact coastal winds that drive upwelling and productivity in these ecosystems.

Ecosystem-based management requires integrated physical studies on biological functions. In this study, we hypothesized that seasonal variation in upwelling-favorable winds has differential influences on species of the central California Current pelagic ecosystem. To test this hypothesis, we developed multivariate indicators of upwelling and species’ responses using wind and sea surface temperature (SST) data from buoys and growth and reproductive data for 11 species of fish and seabirds. From previous work, we predicted that winds and SST could be decomposed into winter and spring/summer ‘modes’ of variability, but only a single mode of “winter/spring” environmental variability was observed. We attribute this difference from expectations to the local and shorter-term measurements of winds and SST used in this study. Most species responded to winds and SST variability similarly, but SST was a better predictor of most biological responses. Both SST and wind were better predictors than the traditional upwelling index. Notably, Pacific sardine (Sardinops sajax) was disassociated with the other biotic measurements and showed no relationships with coastal upwelling. The multivariate indicators developed here are particularly appropriate for integrated ecosystem assessments of climatic influences on marine life because they reflect both structure and processes (upwelling and timing/growth/productivity) known to determine functions in marine ecosystems.