Publications

Use of data-limited methods for setting target catches is increasing in the Northeast U.S., but there remains considerable uncertainty over which methods may be suitable for stocks in the region. We retrospectively evaluated the ability of data-limited methods to set target catches close to the overfishing limit for data-rich stocks in the Northeast U.S. Methods explored include options that would be used in truly data-poor cases (i.e., catch-only methods), but we also evaluated methods with different data requirements for stocks that have information beyond a catch time series. The majority of options we explored that used average catches over some portion of the time period, or adjusted the recent catches based on trends in an index were sensitive to the level of historical exploitation. Such methods produced target catches above the overfishing limit for stocks that had a history of overfishing, or target catches that were overly conservative for stocks with a history of light exploitation. Careful consideration of the level of historical exploitation rates, if possible, is therefore needed if using such approaches are to be applied. Catch curve methods, which require catch-at-age information, were the only approaches not sensitive to the level of historical exploitation, and were largely effective at setting target catches close to the overfishing limit, even for stocks with intense historical exploitation rates. However, there were cases where catch curve methods produced unsustainable target catches, particularly for stocks with episodic recruitments, such that care is needed when implementing catch curve methods.

Many analyses of fishery recovery have demonstrated the potential biological and economic benefits of management reform, but few have compared these to the associated costs of management upgrades, which can be substantial. This study aims to determine if the projected economic benefits of management reform outweigh the increases in management costs required to achieve those benefits. To answer this question, we developed a database of country-level fisheries management costs and use those to estimate the country-level costs of management changes. We use this framework to compare estimates of future costs of management upgrades against their economic benefits in terms of profit. Results indicate that for most nations, including the top 25 fishing nations, management upgrades outweigh their associated costs. This result is robust to a number of alternative assumptions about costs. Results also suggest that stronger reforms such as rights-based management, although sometimes more expensive to implement, can lead to greater net economic benefits compared to alternatives.

The world’s oceans supply food and livelihood to billions of people, yet species’ shifting geographic ranges and changes in productivity arising from climate change are expected to profoundly affect these benefits. We ask how improvements in fishery management can offset the negative consequences of climate change; we find that the answer hinges on the current status of stocks. The poor current status of many stocks combined with potentially maladaptive responses to range shifts could reduce future global fisheries yields and profits even more severely than previous estimates have suggested. However, reforming fisheries in ways that jointly fix current inefficiencies, adapt to fisheries productivity changes, and proactively create effective transboundary institutions could lead to a future with higher profits and yields compared to what is produced today.

Most large-scale conservation policies are anticipated or announced in advance. This risks the possibility of preemptive resource extraction before the conservation intervention goes into force. We use a high-resolution dataset of satellite-based fishing activity to show that anticipation of an impending no-take marine reserve undermines the policy by triggering an unintended race-to-fish. We study one of the world’s largest marine reserves, the Phoenix Islands Protected Area (PIPA), and find that fishers more than doubled their fishing effort once this area was earmarked for eventual protected status. The additional fishing effort resulted in an impoverished starting point for PIPA equivalent to 1.5 y of banned fishing. Extrapolating this behavior globally, we estimate that if other marine reserve announcements were to trigger similar preemptive fishing, this could temporarily increase the share of overextracted fisheries from 65% to 72%. Our findings have implications for general conservation efforts as well as the methods that scientists use to monitor and evaluate policy efficacy.

Land-use regulations can lower real estate prices by imposing costs on property owners, but may raise prices by restricting supply and generating amenities. We study the effects of the California Coastal Act, one of the nation’s most stringent land-use regulations, on the price and rental income of multifamily housing. The Coastal Act applies to a narrow section of the California coast, allowing us to compare properties just on either side of the jurisdictional boundary. The setting is advantageous for the study of land-use regulation: boundary location is plausibly exogenous, which we confirm with historical data on boundary placement, and orthogonal to other jurisdictional divisions. We decompose the effects of the regulation into (i) a neighbor effect, the value of restrictions on adjacent properties, (ii) a local effect, which reflects the net effect of own-lot restrictions and the neighbor effect, and (iii) an external effect, the value of amenities generated by restrictions on all properties within the regulated area. Our analysis of multifamily housing prices reveals local and external effects of approximately +6% and +13%, respectively. We use data on rental income to estimate a zero neighbor effect. Together with evidence on building ages and assessed building and land values, this suggests that property owners anticipate that the Coastal Act will provide protection from undesirable development on adjacent properties, even though material differences have not yet appeared.

I examine the estimated economic, ecological, and food security effects of future fishery management reform in Asia. Without climate change, most Asian fisheries stand to gain substantially from reforms. Optimizing fishery management could increase catch by 24% and profit by 34% over business-as-usual management. These benefits arise from fishing some stocks more conservatively and others more aggressively. Although climate change is expected to reduce carrying capacity in 55% of Asian fisheries, I find that under climate change large benefits from fishery management reform are maintained, though these benefits are heterogeneous. The case for reform remains strong for both catch and profit, though these numbers are slightly lower than in the no-climate change case. These results suggest that, to maximize economic output and food security, Asian fisheries will benefit substantially from the transition to catch shares or other economically rational fishery management institutions, despite the looming effects of climate change.

Low-probability, high-consequence climate change events are likely to trigger management responses that are based on the demand for immediate action from those affected. However, these responses may be inefficient and even maladaptive in the long term.

Climate change has impacted physical, biological and human systems, and many of its effects are expected to increase in severity and magnitude in coming decades¹. Some changes will happen gradually, such as sea-level rise and shifts in species ranges. Other impacts, such as floods, fires and disease outbreaks, are acute, low-probability events with widespread consequences. In light of recent social science research on the role of salience in decision-making, we argue that although the risk of episodic high-impact events can motivate planned adaptation, it is the occurrence of events that often leads to action.

Salience theory predicts that people experiencing low-probability, high-consequence events give those events disproportionate weight in subsequent decision-making because their attention is drawn to them as standing out from the norm². Because governments rely on public perceptions and input to allocate public goods that are intended to modify hazards, events that raise the salience of risk will make people and governments more likely to pay attention to that risk, act on that risk or demand action from others — regardless of whether such actions actually reduce risk. While salience-driven decision-making can facilitate action that reduces risk, it can also lead individuals and governments to respond in ways that are inefficient or even maladaptive — such that the allocation of resources could more effectively address future risks or the responses may actually increase future risks.

Here we describe examples of how salience provides a behavioural link between episodic climate impacts with substantial societal and ecological costs (wildfire, floods, disease outbreaks) and observed responses that can be inefficient or maladaptive (Table 1). Ignoring this behavioural link inhibits successful strategies for climate change adaptation planning.

Sustainable management of complex human–environment systems, and the essential services they provide, remains a major challenge, felt from local to global scales. These systems are typically highly dynamic and hard to predict, particularly in the context of rapid environmental change, where novel sets of conditions drive coupled socio-economic-environmental responses. Faced with these challenges, our tools for policy development, while informed by the past experience, must not be unduly constrained; they must allow equally for both the fine-tuning of successful existing approaches and the generation of novel ones in unbiased ways. We study ocean fisheries as an example class of complex human–environmental systems, and present a new model (POSEIDON) and computational approach to policy design. The model includes an adaptive agent-based representation of a fishing fleet, coupled to a simplified ocean ecology model. The agents (fishing boats) do not have programmed responses based on empirical data, but respond adaptively, as a group, to their environment (including policy constraints). This conceptual model captures qualitatively a wide range of empirically observed fleet behaviour, in response to a broad set of policies. Within this framework, we define policy objectives (of arbitrary complexity) and use Bayesian optimization over multiple model runs to find policy parameters that best meet the goals. The trade-offs inherent in this approach are explored explicitly. Taking this further, optimization is used to generate novel hybrid policies. We illustrate this approach using simulated examples, in which policy prescriptions generated by our computational methods are counterintuitive and thus unlikely to be identified by conventional frameworks.

While the ecological impacts of fishing the waters beyond national jurisdiction (the “high seas”) have been widely studied, the economic rationale is more difficult to ascertain because of scarce data on the costs and revenues of the fleets that fish there. Newly compiled satellite data and machine learning now allow us to track individual fishing vessels on the high seas in near real time. These technological advances help us quantify high-seas fishing effort, costs, and benefits, and assess whether, where, and when high-seas fishing makes economic sense. We characterize the global high-seas fishing fleet and report the economic benefits of fishing the high seas globally, nationally, and at the scale of individual fleets. Our results suggest that fishing at the current scale is enabled by large government subsidies, without which as much as 54% of the present high-seas fishing grounds would be unprofitable at current fishing rates. The patterns of fishing profitability vary widely between countries, types of fishing, and distance to port. Deep-sea bottom trawling often produces net economic benefits only thanks to subsidies, and much fishing by the world’s largest fishing fleets would largely be unprofitable without subsidies and low labor costs. These results support recent calls for subsidy and fishery management reforms on the high seas.

Perhaps the greatest challenge facing global fisheries is that recovery often requires substantial short-term reductions in fishing effort, catches and profits. These costs can be onerous and are borne in the present; thus, many countries are unwilling to undertake such socially and politically unpopular actions. We argue that many nations can recover their fisheries while avoiding these short-term costs by sharply addressing illegal, unreported and unregulated (IUU) fishing. This can spur fishery recovery, often at little or no cost to local economies or food provision. Indonesia recently implemented aggressive policies to curtail the high levels of IUU fishing it experiences from foreign-flagged vessels. We show that Indonesia’s policies have reduced total fishing effort by at least 25%, illustrating with empirical evidence the possibility of achieving fishery reform without short-term losses to the local fishery economy. Compared with using typical management reforms that would require a 15% reduction in catch and 16% reduction in profit, the approach of curtailing IUU has the potential to generate a 14% increase in catch and a 12% increase in profit. Applying this model globally, we find that addressing IUU fishing could facilitate similar rapid, long-lasting fisheries gains in many regions of the world.

Reductions in global fishing pressure are needed to end overfishing of target species and maximize the value of fisheries. We ask whether such reductions would also be sufficient to protect non–target species threatened as bycatch. We compare changes in fishing pressure needed to maximize profits from 4713 target fish stocks—accounting for >75% of global catch—to changes in fishing pressure needed to reverse ongoing declines of 20 marine mammal, sea turtle, and seabird populations threatened as bycatch. We project that maximizing fishery profits would halt or reverse declines of approximately half of these threatened populations. Recovering the other populations would require substantially greater effort reductions or targeting improvements. Improving commercial fishery management could thus yield important collateral benefits for threatened bycatch species globally.

Climate-related impacts to marine ecosystems threaten the biological, social, and economic resilience of the U.S. fishing industry. Changes in ocean conditions and variability in fisheries productivity have stimulated an effort to integrate climate information into fisheries science and management processes to inform more responsive decision-making. However, institutional, capacity, and budget constraints within U.S. federal and state fisheries management agencies may hinder the potential to deliver climate-ready strategies for many fisheries. We examine whether adaptive comanagement as a governance approach can enhance capacity and advance climate-ready fisheries objectives. Adaptive comanagement may improve the quality of science and decision-making needed to prepare for and respond to impacts of climate change in fisheries by taking advantage of skills, technology, and funding often not optimally utilized under the current governance system. We focus on the potential to improve information flows as a means to achieve climate-ready fisheries via adaptive comanagement, but suggest that a greater level of partnership in the management process may be possible in the future after a period of formal experimentation and learning.

How important are coral reefs for food security and to what extent does coral reef conservation contribute to the food security of the coastal communities in the Coral Triangle? Based on the national fish production and consumption data from the Philippines and some data from Indonesia, Clifton and Foale (2017) [12] argued that the pelagic fisheries are far more important than coral reef fisheries for the food security of the Philippines and Indonesia. While it is true that, in totality, populations in both the Philippines and Indonesia rely heavily on pelagic fisheries for animal protein, this commentary demonstrates that coral reef fisheries contribute substantially to the food and livelihood security of coastal communities, which make up the poorest and most food insecure sector of the economy. There is also significant growth potential in nearshore fisheries that can be captured by working to recover currently degraded coral reef ecosystems. Nonetheless, research and institutional reforms in all sources of fish protein (pelagic, demersal, and aquaculture) are urgently needed to improve not only food security but also the lives and livelihoods of coastal fishing households in the Coral Triangle.

Although fishing is one of the most widespread activities by which humans harvest natural resources, its global footprint is poorly understood and has never been directly quantified. We processed 22 billion automatic identification system messages and tracked >70,000 industrial fishing vessels from 2012 to 2016, creating a global dynamic footprint of fishing effort with spatial and temporal resolution two to three orders of magnitude higher than for previous data sets. Our data show that industrial fishing occurs in >55% of ocean area and has a spatial extent more than four times that of agriculture. We find that global patterns of fishing have surprisingly low sensitivity to short-term economic and environmental variation and a strong response to cultural and political events such as holidays and closures.

Marine reserves are implemented to achieve a variety of objectives, but are seldom rigorously evaluated to determine whether those objectives are met. In the rare cases when evaluations do take place, they typically focus on ecological indicators and ignore other relevant objectives such as socioeconomics and governance. And regardless of the objectives, the diversity of locations, monitoring protocols, and analysis approaches hinder the ability to compare results across case studies. Moreover, analysis and evaluation of reserves is generally conducted by outside researchers, not the reserve managers or users, plausibly thereby hindering effective local management and rapid response to change. We present a framework and tool, called “MAREA”, to overcome these challenges. Its purpose is to evaluate the extent to which any given reserve has achieved its stated objectives. MAREA provides specific guidance on data collection and formatting, and then conducts rigorous causal inference analysis based on data input by the user, providing real-time outputs about the effectiveness of the reserve. MAREA’s ease of use, standardization of state-of-the-art inference methods, and ability to analyze marine reserve effectiveness across ecological, socioeconomic, and governance objectives could dramatically further our understanding and support of effective marine reserve management.

In the Old-World vineyards of Europe, a key concept that plays an important role in the production and appreciation of wines is terroir, which refers to the special characteristics of a place that impart unique qualities to the wine produced. We examine whether terroir matters in the New-World wines produced in California's Napa and Sonoma Counties by conducting a hedonic price analysis of vineyard sales over the period 1991 to 2007 to determine the relative effects on vineyard sales prices of designated appellations versus biophysical site attributes commonly associated with terroir, such as slope, aspect, elevation, and climate. Because vineyards that are sold are not necessarily representative of the universe of vineyards, we employ Heckman's two-stage econometric approach to control for possible sample-selection bias. We find that intrinsic site attributes and designated appellations influence vineyard prices, although our results are stronger and more consistent with regard to the influence of appellations. This finding indicates that terroir matters economically, even if the designated appellations have relatively less connection in reality with terroir. (JEL Classifications: C2, Q11)

This paper uses detailed production data from a half million Chinese manufacturing plants over 1998–2007 to estimate the effects of temperature on firm-level total factor productivity (TFP), factor inputs, and output. We detect an inverted U-shaped relationship between temperature and TFP and show that it primarily drives the temperature-output effect. Both labor- and capital- intensive firms exhibit sensitivity to high temperatures. By mid 21st century, if no additional adaptation were to occur, we project that climate change will reduce Chinese manufacturing output annually by 12%, equivalent to a loss of $39.5 billion in 2007 dollars. This implies substantial local and global economic consequences as the Chinese manufacturing sector produces 32% of national GDP and supplies 12% of global exports.

Water scarcity afflicts societies worldwide. Anticipating water shortages is vital because of water’s indispensable role in social-ecological systems. But the challenge is daunting due to heterogeneity, feedbacks, and water’s spatial-temporal sequencing throughout such systems. Regional system models with sufficient detail can help address this challenge. In our study, a detailed coupled human–natural system model of one such region identifies how climate change and socioeconomic growth will alter the availability and use of water in coming decades. Results demonstrate how water scarcity varies greatly across small distances and brief time periods, even in basins where water may be relatively abundant overall. Some of these results were unexpected and may appear counterintuitive to some observers. Key determinants of water scarcity are found to be the cost of transporting and storing water, society’s institutions that circumscribe human choices, and the opportunity cost of water when alternative uses compete.

The demand for air quality depends on health impacts and defensive investments, but little research assesses the empirical importance of defenses. A rich quasi-experiment suggests that the Nitrogen Oxides (NOx) Budget Program (NBP), a cap-and-trade market, decreased NOx emissions, ambient ozone concentrations, pharmaceutical expenditures, and mortality rates. The annual reductions in pharmaceutical purchases, a key defensive investment, and mortality are valued at about $800 million and $1.3 billion, respectively, suggesting that defenses are over one-third of willingness-to-pay for reductions in NOx emissions. Further, estimates indicate that the NBP's benefits easily exceed its costs and that NOx reductions have substantial benefits.