frontiers of real time data analysis in the past ten years researchers have explored the impact of data revisions in many different contexts researchers have examined the properties of data revisions how structural modeling is affected by data revisions how data revisions affect forecasting the impact of data revisions on monetary policy analysis and the use of real time data in current analysis this paper summarizes many of the questions for which real time data analysis has provided answers in addition researchers and institutions have developed better real time data sets around the world still additional research is needed in key areas and research to date has uncovered even more fruitful areas worth exploring jel c52 c53 c80 e01

ecological economic viability as a criterion of strong sustainability under uncertainty strong sustainability according to the common definition requires that different natural and economic capital stocks be maintained as physical quantities separately yet in a world of uncertainty this cannot be guaranteed to therefore define strong sustainability under uncertainty in an operational manner we propose to use the concept of viability viability means that the different components and functions of a dynamic stochastic system at any time remain in a domain where the future existence of these components and functions is guaranteed with sufficiently high probability we develop a unifying and general ecological economic concept of viability that encompasses the traditional ecological and economic notions of viability as special cases it provides an operational criterion of strong sustainability under a mild form of uncertainty and for medium spatial and temporal scales we illustrate this concept and demonstrate its usefulness by applying it to livestock grazing management in semi arid rangelands publication ecological economic viability as a criterion of strong sustainability under uncertainty available from https www researchgate net publication 46490456 ecological economic viability as a criterion of strong sustainability under uncertainty accessed apr 3 2017

economic viability and small scale fisheries a review abstract globally over 90 of all fishing vessels and about 22 million fishers are considered small scale despite their high numbers small scale fisheries are often understudied they are usually economically and politically marginalized and therefore vulnerable to large scale threats e g globalized markets to support this sector and contribute to its sustainability we argue that it is fundamental to understand how economically viable small scale fisheries are hence the main objective of this article is to critically review and describe the current discourse on the economic viability of small scale fisheries we find that currently economic viability is mainly equated with financial viability where profitability is the goal in consideration of socio economic aspects the maintenance of nonnegative net benefits to society is often not considered in current notions of economic viability while these shortcomings have been acknowledged in some of the existing literature our review shows that they have not yet been addressed comprehensively we therefore conclude that it is necessary to develop or expand current methods to better take into account social aspects when assessing the economic viability of small scale fisheries this would help find solutions to make these fisheries less vulnerable and better equipped to face large scale processes of change

renewable resource management with environmental prediction variations in environmental conditions affect renewable resource growth the ability to predict such variations is improving providing scope for improved management we generalize a common stochastic stock recruitment model to explore how optimal management changes with environmental prediction we obtain three main results first while it might seem that a prediction of adverse future conditions should lead to more conservative management the opposite may be true second optimal management requires only a one period ahead forecast suggesting forecast accuracy is more important than forecast lead time finally we derive conditions on environmental fluctuations guaranteeing positive optimal harvest in every period gestion d une ressource renouvelable quand on predit les conditions futures de l environnement les variations dans les conditions de l environnement affectent la croissance de la ressource renouvelable la capacitea prevoir ces variations s ameliore et ouvre la possibilite d ameliorer la gestion de la ressource les auteurs utilisent un modele de ressource renouvelable avec croissance stochastique et obtiennent trois resultats d abord alors qu il peut sembler que des previsions pessimistes de conditions difficiles dans l avenir peuvent conduire a une gestion plus conservatrice le contraire peut etre vrai ensuite la gestion optimale requiert seulement une prediction pour la prochaine periode voila qui suggere qu il est plus important d avoir une prevision exacte que d avoir des previsions a plus long terme enfin on developpe les conditions pour les fluctuations de l environnement qui garantissent une recolte positive optimale a chaque periode

pulse fishing and stock uncertainty large variation in stock dynamics affects the accuracy of stock estimates which fisheries managers rely on when determining quotas and other regulations the purpose of this paper is to investigate the implications of uncertainty on pulse fishing we show that as the variance of the random natural fluctuations increases the optimal pulse length decreases and converge toward a constant escapement policy hence in fisheries with large natural variability a constant escapement policy is a good approximation of the optimal policy

the relationship between resilience and sustainability of ecological economic systems resilience as a descriptive concept gives insight into the dynamic properties of an ecological economic system sustainability as a normative concept captures basic ideas of intergenerational justice when human well being depends on natural capital and services thus resilience and sustainability are independent concepts in this paper we discuss the relationship between resilience and sustainability of ecological economic systems we use a simple dynamic model where two natural capital stocks provide ecosystem services that are complements for human well being to illustrate different possible cases of the relationship between resilience and sustainability and to identify the conditions under which each of those will hold a resilience of the system is necessary but not sufficient for sustainability b resilience of the system is sufficient but not necessary for sustainability c resilience of the system is neither necessary nor sufficient for sustainability and d resilience is both necessary and sufficient for sustainability we conclude that more criteria than just resilience have to be taken into account when designing policies for the sustainable development of ecological economic systems and vice versa the property of resilience should not be confused with the positive normative connotations of sustainability c 2011 elsevier b v all rights reserved

a framework for the analysis of evolving patron client ties in agrarian economies abstract this paper looks systematically at the various factors that can account for the disappearance or the transformation of the institution of patronage that used to structure labor and other relationships in many agrarian societies of the past it is an attempt to offer a unifying framework capable of guiding one s attention to the relevant variables and to the way they interact in this process the rather simplistic view according to which there is a unique linear path through which patronage evolves is called into question and a number of different scenarios are instead presented these alternatives are illustrated with reference to asia

agriculture in recent development theory abstract this paper is a critical review of recent contributions to the literature on agriculture in development theory it considers and compares the main lines of advance made within neoclassical neo marxian and structuralist approaches recent neo marxian and structuralist studies of agrarian development reveal that traditional agriculture is neither stationary nor efficient that resource allocation cannot be separated from wealth distribution or production organization that forms of surplus appropriation do not necessarily follow the dictates of efficiency that the social relations of production may inhibit accumulation and determine the forms of technological change that the state s role in primitive accumulation is more economic than explicitly coercive political and that political and macroeconomic constraints preclude a simple get the prices right view of the intersectoral terms of trade the thrust of these developments is to challenge both neoclassical and some orthodox marxian formulations of agrarian development issues and add to the insights to be gleaned from a political economy of development

renewable resource management with stochastic recharge and environmental threats abstract exploitation diminishes the capacity of renewable resources to withstand environmental stress increasing their vulnerability to extreme conditions that may trigger abrupt changes the onset of such events depends on the coincidence of extreme environmental conditions and on the resource state determining its resilience when the former is uncertain and the latter evolves stochastically the uncertainty regarding the event occurrence is the result of the combined effect of these two uncertain components we study optimal management in this setting the environmental threat renders the single period discount factor policy dependent and as a result the compound discount factor becomes history dependent existence of an optimal markovian deterministic stationary policy is established and the optimal state process is shown to converge to a steady state distribution

a qualitative dynamical modelling approach to capital accumulation in unregulated fisheries capital accumulation has been a major issue in fisheries economics over the last two decades whereby the interaction of the fish and capital stocks were of particular interest because bio economic systems are intrinsically complex previous efforts in this field have relied on a variety of simplifying assumptions the model presented here relaxes some of these simplifications problems of tractability are surmounted by using the methodology of qualitative differential equations qde the theory of qdes takes into account that scientific knowledge about particular fisheries is usually limited and facilitates an analysis of the global dynamics of systems with more than two ordinary differential equations the model is able to trace the evolution of capital and fish stock in good agreement with observed patterns and shows that over capitalization is unavoidable in unregulated fisheries r 2005 elsevier b v all rights reserved

the triple bottom line meeting ecological economic and social goals with individual transferable quotas this paper deals with the sustainable management of a renewable resource based on individual and transferable quotas itqs when agents differ in terms of harvesting costs or catch capability in a dynamic bio economic model we determine the feasibility conditions under which a fishery manager can achieve sustainability objectives which simultaneously account for stock conservation economic efficiency and maintenance of fishing activity for the agents along time we show how the viability of quota management strategies based on itq depends on the degree of heterogeneity of users in the fishery the current status and the dynamics of the stock together with the selection of tac schedules in particular for a given stock we compute the maximin effort for a given set of agents and we derive the maximal number of active agents for a given guaranteed effort an application to the nephrops fishery in the bay of biscay illustrates the results

storage and viability of a fishery with resource and market dephased seasonalities in this study we analyse the role of the storageregulation in a fishery s production process when theresource exploited and the market to which theproduction is exported are characterized by seasonaldephased oscillations for this purpose we built up adynamic model drawn from the french guyana shrimpfishery example the underlying objective of the modelis not the maximisation of a given criterion as wouldbe in the optimal control approach but merely themaintenance of the fishery s economical viability thefundamental principle is here to try to preserve asmany as possible viable control options theconditions to achieve and maintain this viability arecaptured in a certain number of constraints theanalysis points out periods and situations within theseason where the fishermen must anticipate theevolution of their storage to avoid violating thoseviability constraints the study also indicates howthe fishery s viability can be ensured even if theexploitation costs exceed the commercial value of thelandings for a finite part of the year however whenthe resource s and or market s oscillations are toolarge the fishery may be not viable any longer and itappears that the crisis can not be removed byinvesting in larger storage capacities

defining viable recovery paths toward sustainable fisheries this paper develops a formal analysis of the recovery process for a fishery from crisis situations to desired levels of sustainable exploitation using the theoretical framework of viable control we define sustainability as a combination of biological economic and social constraints which need to be met for a viable fishery to exist biological constraints are based on the definition of a minimum resource stock to be preserved economic constraints relate to the existence of a guaranteed profit per vessel social constraints refer to the maintenance of a minimum size of the fleet and to the maximum speed at which fleet adjustment can take place using fleet size adjustment and fishing effort per vessel as control variables we first identify the states of this bioeconomic system for which sustainable exploitation is possible i e for which all constraints can be dynamically met such favorable states are called viable states we then examine possible transition phases from non viable to viable states we characterize recovery paths with respect to the time of crisis of the trajectory which is the number of periods during which the constraints are not respected the approach is applied to the single stock of the bay of biscay nephrops fishery the transition path identified through the viability approach is compared to the historical recovery process and to both open access and optimal harvesting scenarios

ecological and economic sustainability in fishery management a multi agent model for understanding competition and cooperation recent studies have shown that many marine ecosystems are experiencing an accelerating loss of population and biodiversity it is apparent that there is a growing disparity between the available supply of fish and the desire of the growing world population to catch them although studies have begun to question the ecological sustainability of managed fishery systems they often omit the corresponding effects on the economic sustainability of fishery industries this is particularly important in rural coastal areas where the fishing industry is often a dominant employer in this article we analyze the interactions between economic and ecological dynamic systems using a multi agent dynamic model of fishery management multiple agents fishers harvest multiple fish species and adapt the amount and allocation of their effort to their value functions which are given as net profits of the fish harvest sold for a market price this is largely unique in fishery models since many econometric studies view fishers as represented by homogenous average agents we introduce and compare two different decision rules governing the behavior of fishers engaged in a competitive market we demonstrate a situation where both behaviors lead to a decline of all fish stocks as well as profits for most fishers as an alternative we introduce a cooperative approach in which fisheries jointly set sustainable limits for total harvest and effort that are then distributed to the fishers according to distribution rules the simulation reveals that fish stocks and profits can stabilize at significantly higher levels in the cooperative case leading to a continuous accumulation of capital for all fishers this model demonstrates key aspects of overfishing conflicts that can be overcome through planned fishing quotas and cooperative market mechanisms it also demonstrates a novel approach for simulating the dynamic behavior of heterogeneous fishers

willingness to pay for renewable energy primary and discretionary choice of british households for micro generation technologies this paper documents the policy context of renewable energy production in the european union the research adopts a choice experiment approach to investigate households wtp for these renewable energy technologies in the uk the micro generation technologies comprise solar photovoltaic micro wind solar thermal heat pumps and biomass boilers and pellet stoves the study compares the results from conditional and mixed logit models which estimate the distribution of utility coefficients and then derives wtp values as a ratio of the attribute coefficient to the price coefficient with a model in which the wtp distribution is estimated directly from utility in the money space the results suggest that whilst renewable energy adoption is significantly valued by households this value is not sufficiently large for the vast majority of households to cover the higher capital costs of micro generation energy technologies

a viability analysis for a bio economic model abstract this paper presents a simple dynamic model dealing with the management of a marine renewable resource but instead of studying the ecological and economic interactions in terms of equilibrium or optimal control we pay much attention to the viability of the system or in a symmetric way to crisis situations these viability crisis situations are defined by a set of economic and biological state constraints the analytical study focuses on the compatibility between the state constraints and the controlled dynamics using the mathematical concept of viability kernel we reveal the situations and if possible management options to guarantee a perennial system going further we define overexploitation indicators by the time of crisis function in particular we point out irreversible overexploitation configurations related to the resource extinction

off season tourists and the cultural offer of a mass tourism destination the case of rimini abstract this paper assesses the potential implications on off season tourism of enhancing the cultural offer of rimini a popular italian seaside holiday destination hosting about 12 million overnight stays per year since more than 9 million of these stays are concentrated in the summer season in the last 20 years rimini has been undergoing a policy of seasonality smoothing which mainly pivots around business and cultural tourism this assessment has been carried out through discrete choice experiments submitted to a sample of about 800 tourists who visited rimini outside the summer months since tourism can be viewed as a composite good which overall utility depends on how the component characteristics are arranged the choice experiments allow to disentangle the importance and the willingness to pay of tourists for different attributes of the holiday the choice model incorporates a number of possible changes to actual tourism features which are also the subject of public debate including them in hypothetical alternative holiday packages the conditional logit analysis of the choice experiments can highlight any synergy or trade off between cultural and business tourism results suggest that business and leisure tourists share many features related to the use of the territory while there are important trade offs between these two groups and cultural tourists since business tourists have a higher willingness to extend their stay a softer budget and their demand is also complementary to the demand of summer tourists brau scorcu vici 2009 from the destination point of view investing in this market segment would be the best option although a second best however cultural tourists share with the local population of rimini many aspects of the demand of territory figini castellani vici 2009 hence cultural tourism can play a fundamental role in the intermediate season as a tool for smoothing seasonality to diversify investments and to give value to the city s cultural heritage

maximum economic yield fishery management in the face of global warming abstract this paper deals with fishery management in the face of the ecological and economic effects of global warming to achieve this a dynamic bioeconomic model and model based scenarios are considered in which the stock s growth function depends on the sea surface temperature the model is empirically calibrated for the french guiana shrimp fishery using time series collected over the period 1993 2009 three fishing effort strategies are then compared under two contrasted ipcc climate scenarios rcp 8 5 and rcp 2 6 a first harvesting strategy maintains the status quo in terms of fishing effort a more ecologically oriented strategy based on the closure of the fishery is also considered a third strategy which relates to maximum economic yield mey is based on the optimisation of the net present value derived from fishing the results first show that status quo fishing intensity combined with global warming leads to the collapse of the fishery in the long run secondly it turns out that the closure strategy preserves stock viability especially under the optimistic climate scenario thirdly the mey strategy makes it possible to satisfy bioeconomic performances requirements with positive stock and profit once again especially under the optimistic warming scenario consequently mey emerges as a relevant bioeconomic strategy in terms of adaptation to climate change but only in connection with climate change mitigation

the effect of individual ability to choose scale heterogeneity on the valuation of environmental goods christie m gibbons j 2011 the effect of individual ability to choose scale heterogeneity on the valuation of environmental goods ecological economics 70 12 2250 2257

renewable resource harvesting under correlated biological and economic uncertainties implications for optimal and second best management biologists have long recognized environmental disturbances impact both the growth of renewable resources and the efficiency of harvest effort however models of renewable resource management under uncertainty have commonly assumed economic and biological uncertainties to be uncorrelated we present examples of valuable fish species that experience correlated variation in biological growth and catchability in response to a common environmental disturbance building correlation into a model of renewable resource management under uncertainty we find correlation to alter the optimal response by managers to cost disturbances and impact the value of retaining intra period flexibility over harvest targets examining the performance of three harvest control mechanisms harvest quotas effort quotas and taxes reveals that positive correlation between costs and growth favors harvest quotas over effort quotas and effort quotas over taxes and vice versa the model is then applied numerically to the pacific bigeye tuna fishery which experiences positively correlated shocks driven by the el nino southern oscillation correlation qualitatively changes the optimal response to a cost shock and harvest quotas are found to be strongly favored over both effort quotas and taxes

endogenous fishery management in a stochastic model why do fishery agencies use tacs along with fishing periods this paper seeks to explain the circumstances under which using total allowable catch tac as an instrument to manage a fishery along with fishing periods may be of interest from a regulatory point of view the deterministic analysis by homans and wilen j environ econ manag 32 1 21 1997 and anderson ann oper res 94 231 257 2000 is thus extended to a stochastic scenario where the resource cannot be measured accurately the resulting model is solved numerically to find the optimal control rules in the iberian sardine stock three relevant conclusions can be highlighted from simulations first the greater the uncertainty regarding the state of the stock the lower the probability of the fishery being closed before the end of the fishing period second the use of tacs as a management instrument in fisheries that are already regulated by fishing periods leads to i an increase in the optimal season length and harvests especially for medium and high numbers of licences ii improved biological and economic variables when the fleet is large and iii extinction risk for the resource being eliminated third the regulator would rather select the number of licences than restrict the season length

risk and sustainability assessing fishery management strategies we develop a theoretical framework to assess the sustainability of fishery management strategies when the bioeconomic dynamics are marked by uncertainty and several conflicting objectives have to be accounted for stochastic viability ranks management strategies according to their probability to sustain economic and ecological outcomes over time the approach is extended to build stochastic sustainable production possibility frontiers representing the trade offs between sustainability objectives at any risk level given the current state of the fishery this framework is applied to a chilean fishery faced with el nino uncertainty we study the viability of effort and quota strategies when catch and biomass levels have to be sustained we show that 1 for these sustainability objectives whatever the level of the outcomes to be sustained quota based management results in a better viability probability than effort based management and 2 the fishery s historical quota levels were not sustainable given the stock levels in the early 2000s

impact of cultured shrimp industry on wild shrimp fisheries analysis of price determination mechanisms and market dynamics cultured shrimp production has been growing dramatically on the world market over the last 15 years and some of the farm raised species are now considered as price indicators on the main market places one may therefore expect the price of theses cultured shrimp to have an impact on the price formation of other species and especially on wild shrimp with which they compete in this paper the authors address this question in the case of the wild shrimp penaeus subtilis exploited by the french guyana fishery south america and competing on the french market with the cultured thai shrimp back tiger a series of econometric tests issued from the co integration theory is performed between the price series of the two products these tests indicate that the two series are co integrated and that the black tiger market acts as a market leader for the french guyana shrimp product the authors then discuss the reasons of the current predominance of farm raised shrimp on wild caught product and in particular the french guyana shrimp and identify the constraints that the french market demand induces on both producers and importers in the light of this analysis a commercial strategy that would mitigate the impact of the thai shrimp on the french guyana product is suggested

on functions quality and timeliness of economic information economic decisions confront more uncertainty as they grow in scope and reach further into the future they are likely to do so increasingly in decentralized economies that expand and diversify the economic incentives to reduce uncertainty and improve predictions and decisions give rise to the demand for large amounts of diverse information this is not a new phenomenon of course but it is revealed more clearly than ever in the present era of great advances in informational technology for now the demand is to a large extent visibly satisfied the knowledge industries or services of inquiring comthe uncertainty about economic information increases with the probability of error in the underlying data and their processing and interpretation many errors cannot be promptly detected and eliminated but can be gradually reduced over time as attested by the revisions in economic statistics this paper presents substantial evidence on the accuracy of provisional estimates of quarterly and monthly changes in 18 important variables measures of several aspects of data quality and of average lags of data release and signal detection are provided for a collection of 110 widely used economic indicators these materials help identify the location of the more serious measurement errors by variables and period and they show that informational lags of 5 and more months are frequent this paper is part of the national bureau of economic research program on economic fluctuations it was presented at the first international symposium on forecasting in quebec city on may 27 1981 and at the ifo institute for economics research in munich on september 23 1981 financial support from the national science foundation and the aid of the graduate school of business of the university of chicago and nber are gratefully acknowledged i am indebted to louis lambros for helpful suggestions and efficient research and to john gould and geoffrey moore for useful comments 1 growth in the modem economy is motivated by the desire to accumulate human and physical resources capital in the most general sense and is accomplished by actions that necessarily have long term consequences the decisions to choose these particular courses of action strategies must therefore be based on similarly long expectations which are fallible as the risk is high so is the premium on any knowledge that might help the decision maker

what is ecological economics ecological economics addresses the relationships between ecosystems and economic systems in the broadest sense these relationships are the locus of many of our most pressing current problems i e sustainability acid rain global warming species extinction wealth distribution but they are not well covered by any existing discipline environmental and resource economics as it is currently practiced covers only the application of neoclassical economics to environmental and resource problems ecology as it is cur rently practiced sometimes deals with human impacts on ecosystems but the more common tendency is to stick to natural systems ecological economics aims to extend these modest areas of overlap it will include neoclassical environmental economics and ecological impact studies as sub sets but will also encourage new ways of thinking about the linkages between ecological and economic systems we have chosen the name ecological economics for this area of study because it implies a broad ecological interdisciplinary and holistic view of the problem of studying and managing our world the earth from space cover of the journal reflects this global holistic perspective we did not intend to imply with the ordering of the two words in the title that the journal is mainly an economics journal it is intended to be a new approach to both ecology and economics that recognizes the need to make economics more cognizant of ecological impacts and dependencies the need to make ecology more sensitive to economic forces incentives and constraints and the need to treat integrated economic ecologic systems with a common but diverse set of conceptual and analytical tools there was much discussion of other possible names such as economic ecology or ecology and economics or some conjoining of the two words that to me end up being confusing tongue twisters like ecolnomics or econology but ecological economics seemed to get closest to the mean ing we desired while still being evocative to the uninitiated

rent income distribution and growth in an underdeveloped agrarian economy abstract a model is constructed to examine the determination of income distribution in an underdeveloped agrarian economy such as the indian one in which both rich capitalist farmers and poor subsistence farmers rent in land from landlords it is used to analyse the growth and income distributional consequences of different kinds of institutional and technological changes the possibilities of the growth of capitalism and the impact of industrial expansion

cooperation in a stochastic transboundary fishery the effects of implementation uncertainty versus recruitment uncertainty this paper examines how non binding cooperative agreements on fisheries management can be sustained when the management plans in participating countries are implemented imperfectly and compares the effects of implementation uncertainty and of recruitment uncertainty on the potential for cooperation the model developed assumes two countries that share a fish stock reproduction depends on how much fish each country leaves behind after harvesting and hence on random variation in each country s achieved abandonment level a self enforcing agreement is proposed that accounts for the random variation the agreement is illustrated with a numerical example a self enforcing cooperative solution can only be sustained when uncertainty is not pronounced and when the two countries control close to equal shares of the fishery even when a cooperative agreement can be achieved frequent phases of reversion to non cooperative harvest levels are needed to support the agreement a comparison of the effects of recruitment and implementation uncertainty on implicit cooperation indicates that implementation uncertainty is more likely to hamper cooperation

stated preferences of tourists for eco efficient destination planning options abstract eco efficiency is a concept that prescribes reducing the amount of energy and natural resources used as well as wastes and pollutants discharged in the production of goods and services numerous approaches to achieving greater levels of eco efficiency have been suggested for tourism operations and destinations however none of these options have been examined with respect to tourist responses to them this paper uses a discrete choice experiment to examine visitor preferences for a set of hypothetical tourism destination eco efficiency strategies visitors preferred eco efficient planning options to business as usual scenarios the degree of support for the various planning options differed by market segments overall tourist support existed for many options that could increase the overall eco efficiency of destinations visitors were also willing to tolerate additional fees for services that might help to offset the environmental impacts of their behaviours by having respondents evaluate and trade off several resort eco efficiency strategies simultaneously the discrete choice experiment provided a more comprehensive and realistic assessment of eco efficiency options than would be possible using traditional survey methods

does the optimal size of a fish stock increase with environmental uncertainties we analyze the effect of environmental uncertainties on optimal fishery management in a bio economic fishery model unlike most of the literature on resource economics but in line with ecological models we allow the different biological processes of survival and recruitment to be affected differently by environmental uncertainties we show that the overall effect of uncertainty on the optimal size of a fish stock is ambiguous depending on the prudence of the value function for the case of a risk neutral fishery manager the overall effect depends on the relative magnitude of two opposing effects the convex cost effect and the gambling effect we apply the analysis to the baltic cod and the north sea herring fisheries concluding that for risk neutral agents the net effect of environmental uncertainties on the optimal size of these fish stocks is negative albeit small in absolute value under risk aversion the effect on optimal stock size is positive for sufficiently high coefficients of constant relative risk aversion

allocating resources in an uncertain world water management and endangered species instream flows may be essential in protecting aquatic species that are threatened or endangered an economic model of the optimal allocation of water under pure uncertainty is developed with particular attention paid to the situation when a species characterized by critical depensation is affected by instream flows we adopt the notion of pure uncertainty that frank knight and daniel ellsberg intended which applies when decision makers cannot reduce their uncertainty to a unique probability distribution following recent work by hansen sargent and others we employ robust control as a way to deal with this problem copyright 2008 oxford university press

on uncertain renewable resource stocks optimal harvest policies and the value of stock surveys abstract annual harvest quotas are commonly employed in the management of renewable resource stocks commercial fisheries being a prime example such resource stocks often undergo quite significant natural fluctuations to which quotas must be adapted a further complication arises from the fact that estimates of stock abundance are often highly uncertain in this paper a bayesian approach is used to model optimal quota decisions for an uncertain fluctuating renewable resource stock

optimal management with reversible regime shifts abstract in this paper we examine the management of a natural resource a fishery subject to regime shifting dynamics a regime shift is defined as an episode in which the dynamics of the resource can switch between two alternative regimes at random times specifically we study the impact of reversible regime switching both observed and unobserved on optimal harvesting policy the case in which the regime is not directly observed i e observational uncertainty is addressed by using the extended pomdp approach developed in fackler and pacifici 2014 we illustrate the performance of the model under different assumptions on the underlying stochastic growth variability the biological structure of the stock in different regimes and the resilience of the regimes when the regime is known optimal policies depend on the population level and which regime is currently active when the regime is unobserved on the other hand the optimal policy depends on the population level and a belief distribution about the current regime in general when the probability of regime change is fixed and hence is not affected by harvesting policy the optimal policy is of the constant escapement variety when the probability of switching regime is endogenous the optimal policy is no longer of the constant escapement type optimal policies when the regime is uncertain are approximately equal to a weighted average of the policies when the regime is certain with the weights equal to the beliefs in the associated regimes but there are differences

fishery management under multiple uncertainty abstract among others who point to environmental variability and managerial uncertainty as causes of fishery collapse roughgarden and smith proc natl acad sci 93 1996 5078 argue that three sources of uncertainty are important for fisheries management variability in fish dynamics inaccurate stock size estimates and inaccurate implementation of harvest quotas we develop a bioeconomic model with these three sources of uncertainty and solve for optimal escapement based on measurements of fish stock in a discrete time model among other results we find 1 when uncertainties are high we generally reject the constant escapement rule advocated in much of the existing literature 2 inaccurate stock estimation affects policy in a fundamentally different way than the other sources of uncertainty and 3 the optimal policy leads to significantly higher commercial profits and lower extinction risk than the optimal constant escapement policy by 42 and 56 respectively

fisheries management under cyclical population dynamics cycles in environmental conditions e g sea surface temperature directly impact fish growth this paper extends the classical gordon schaefer fishery model by replacing the constant growth rate with a cyclical growth rate the optimal harvest rate is shown to fluctuate but the cycle of the harvest rate lags the cycle of the biological growth function with the highest harvest rate occurring after biological conditions start to decline simulations contrast various fishing policies and illustrate the proclivity to crash a fishery if it is wrongfully managed as if there is a constant growth rate with i i d environmental shocks finally we show that small cyclical fluctuations in one species can result in large fluctuations in the optimal harvest rate of another species if the fish species are interlinked through predator prey relationships

partial enclosure of the commons abstract we examine the efficiency distributional and environmental consequences of assigning spatial property rights to part of a spatially connected natural resource while the remainder is competed for by an open access fringe we refer to this as partial enclosure of the commons we obtain sharp analytical results regarding partial enclosure of the commons including 1 while second best it typically improves welfare relative to no property rights 2 all resource users can be made better off 3 positive rents arise in the open access area and 4 the resource maintains higher stocks under spatial heterogeneity we also characterize spatial regions that are ideal candidates for partial enclosure typically society should seek to enclose those patches with high environmental productivity and high self retention but whether high economic productivity promotes or relegates a patch may depend on one s objective

commercial fisheries under price uncertainty abstract the deterministic models applied in economics of fisheries are extended to comprise price uncertainty and risk aversion among the fishing units it is proved that in the open access fishery both the total fishing effort and the number of fishing units are reduced as the variance of the price increases that the total fishing effort may be smaller in the open access fishery than in the optimal fishery at a high variance that only a fixed producer price system can create a first best optimum and that a tax on revenue is more efficient than both fishing unit quotas or tax on catch

uncertainty in the monetary aggregates sources measurement and policy effects for a variety of reasons observed data on the monetary aggregates are subject to uncertainty or error in some instances first published data are revised at a later date due to errors in preliminary data which can be observed and corrected in others the error persists in the final data cutting across this classification are the numerous sources of error including definitional error transitory error seasonal adjustment error sampling clerical or reporting error etc this survey paper deals with the sources and where possible magnitudes of uncertainties in monetary series the next three sections discuss conceptual and definitional issues and the current procedures for assembling the money supply data sections 5 through 7 then consider respectively uncertainty due to sampling and reporting transitory variation and seasonal adjustment some implications including possible consequences for monetary policy and the effects on relationships to other series are assessed in sections 8 and 9 and the concluding section presents some suggestions for dealing with errors in the aggregates

fisheries management with stock growth uncertainty and costly capital adjustment we develop a dynamic model of a fishery which simultaneously incorporates random stock growth and costly capital adjustment numerical techniques are used to solve for the resource rent maximizing harvest and capital investment policies capital rigidities bring diminishing marginal returns to the current period harvest and introduce an incentive to smooth the catch over time with density dependent stock growth however catch smoothing increases stock variability resulting in reduced average yields the optimal management policy balances the catch smoothing benefits against yield loss we calibrate the model to the alaskan pacific halibut fishery to demonstrate the main insights

south african land policy the legacy of history and current options abstract the highly dualistic farm structure of south africa and the low productivity of native african farmers have been the result of systematic distortions in land allocation output markets the provision of infrastructure agricultural credit and services the dualistic structure did not emerge because of genuine economies of scale in the large commercial sector other countries in latin america and africa that once supported a dualistic farm size structure through similar distortions have either implemented large scale land reforms or have experienced decades of peasant revolts and civil war the paper compares these international experiences to south africa and outlines judicial and market assisted approaches to south african land reform

rational expectations and macroeconomic forecasts the article presents extensive results from testing for bias and serially correlated errors in a collection of time series of quarterly multiperiod forecasts for six variables including real gnp growth inflation and unemployment the analysis covers responses by 79 frequent participants in economic outlook surveys conducted regularly since 1968 it shows much greater incidence of apparently systematic errors for inflation than for the other variables also the tests are more favorable to composite group forecasts than to most of the individual forecast sets

groundwater management in a food security context this article analyzes the sustainability of market based instruments such as tradable permits for the management of a renewable aquifer used for irrigated agriculture in our dynamic hydro economic model a water agency aims at satisfying a food security constraint within a tradable permit scheme in the presence of myopic heterogeneous agents we identify analytically the viability kernel that defines the states of the resource yielding inter temporal feasible paths able to satisfy the set of constraints over time and the associated set of viable quota policies we then illustrate the theoretical results of the paper with numerical simulations based on the western la mancha aquifer

fishery management under poorly known dynamics abstract adapting fishing regulations in a highly uncertain environment remains a complex challenge for managers who have to deal with non linear dynamics of fish population and harvest levels in this research a recent method of stochastic control is adapted to a general fishery management problem under multiples sources of uncertainty related to the dynamics of the fish population and the effect of fishing on its growth the question is about adjusting permanently the management rule or to hold a fixed policy thus avoiding additional noise the mathematical problem developed here though oversimplified represents an original approach to the fishery management issue inspired by the monetary policy challenge of a central bank brainard principle it assumes that control variation increases the level of uncertainty namely cviu approach under particular conditions resulting in preferable inaction regions for managers we specify these conditions to show that the management of a poorly known fishery is still possible by using a cviu approach

estimation of the public benefits of urban water supply improvements in ethiopia a choice experiment improving existing drinking water supply services in developing countries depends crucially on available financial resources cost recovery rates of these services are typically low while demand for more reliable services is high and rapidly growing most stated preference based demand studies in the developing world apply the contingent valuation method and focus on rural areas this study examines household willingness to pay wtp for improved water supply services in a choice experiment in an urban area in ethiopia a country with the lowest water supply coverage in sub saharan africa the design of the choice experiment allows estimation of the value of both drinking water supply reliability and safety the estimated economic values can be used in policy appraisals of improved supply investment decisions despite significant income constraints households are willing to pay up to 80 extra for improved levels of water supply over and above their current water bill women and households living in the

a more timely and useful index of leading indicators effectively predicting cyclical movements in the economy is a major challenge the u s leading index li has long been used to analyze and predict economic fluctuations we describe and test a new procedure for making the li more timely the new li significantly outperforms its older counterpart it offers substantial gains in real time out of sample forecasts of changes in aggregate economic activity real gdp the index of coincident indicators and industrial production and provides timely and accurate ex ante information for predicting not only business cycle turning points but also monthly changes in the economy

the effect of data revisions and additional observations on time series estimates 1987 the effect of data revisions and additional observations on time series estimates applied economics vol 19 no 3 pp 347 353

on optimal wage indexation the observed practice of contracting for labor services in advance introduces stickiness or friction into the economic system in the presence of monetary and real stochastic disturbances the stability of the levels of employment and output hinges on the nature of the wage contracts in this paper we demonstrate the existence of optimal indexation schemes that are capable of eliminating the aforementioned friction by duplicating the equilibrium that would obtain if labor services were contracted for after the stochastic disturbances were realized

deriving and testing efficient estimates of wtp distributions in destination choice models estimation of welfare measures is often a dominant driver in the empirical literature on nonmarket valuation to this end qualitative choice models based on random utility theory have been widely employed in outdoor recreation studies a frequent goal of applied studies has been the estimation of welfare changes associated with site attribute changes at recreation sites in order to inform regulatory policy and resource management we review the evolution of the methodology of random utility theory in this field with a focus on taste heterogeneity models and then focus on the recent proposal of specifying utility in the wtp space train k weeks m 2005 discrete choice models in preference space and willing to pay space in scarpa r alberini a eds applications of simulation methods in environmental and resource economics chapter 1 springer dordrecht pp 1 16 our empirical application is on outdoor alpine recreation data we emphasize the efficiency and direct testing that using the maximum simulated likelihood estimator affords to practitioners using the wtp space approach and illustrate these with examples

harvesting in a fishery with stochastic growth and a mean reverting price we analyze a continuous nonlinear bioeconomic model to demonstrate how stochasticity in the growth of fish stocks affects the optimal exploitation policy when prices are stochastic mean reverting and possibly harvest dependent optimal exploitation has nonlinear responses to the price signal and should be conservative at low levels of biological stochasticity and aggressive at high levels price stochasticity induces conservative exploitation with little or no biological uncertainty but has no strong effect when the biological uncertainty is larger we further observe that resource exploitation should be conservative when the price reverts slowly to the mean simulations show that in the long run both the stock level and the exploitation rate are lower than in the deterministic solution with a harvest dependent price the long run price is higher in the stochastic system the price mean reversion rate has no influence on the long run solutions

uncertain measurements of renewable resources approximations harvesting policies and value of accuracy abstract this paper deals with the management of renewable resources subject to measurement error the method stochastic optimization in policy space sops allows for more general solutions to problems that are not lq than earlier attempts measurement errors are found to be more important for quota policies than natural stochastic variation with little error filtering in time or in policy space is important with considerable error caution becomes important various approximations are compared policies based simply on historical measurements are found to give higher expected values than policies based on advanced kalman filter estimates values of measurement accuracy are estimated

maximin viability and sustainability the maximin criterion defines the highest utility level that can be sustained in an intergenerational equity perspective the viability approach makes it possible to characterize all the economic trajectories sustaining a given not necessarily maximal utility level in this paper we exhibit the strong links between maximin and viability we show that the value function of the maximin problem can be obtained in the viability framework and that the maximin path is a particular viable path this result allows us to extend the recommendations of the maximin approach beyond optimality to characterize the sustainability of economic trajectories which differ from the maximin path attention is especially paid to non negative net investment at maximin accounting prices which is shown to be necessary to maintain the productive capacity of the economy whether the development path is optimal or not our results provide a new theoretical ground to account for sustainability in imperfect economies based on maximin prices

productivity and distribution under cropsharing tenancy abstract this paper develops a model of sharecropping assuming tenant autonomy competitive behavior of landlords and laborers and endogenously determined wage and share rental rates the coexistence of wage labor and sharecropping is explained in terms of their incentive labor process and risk sharing characteristics sharecropping serves as a surrogate for the direct supervision of the labor process its incidence is shown to rise in the presence of unemployment at a subsistence wage the model implies that the abolition of tenancy will raise output raise labor income and reduce land income

optimal growth with unobservable resources and learning abstract this paper examines the problem of choosing optimal resource consumption from an imperfectly observable aggregate capital wealth or resource stock which the decision maker learns about over time learning is complicated by the fact that the planner receives information about an object the true resource stock which is a moving target under the assumption that the utility of zero consumption is we show that the optimal policy follows a completely deterministic cautious or minmax policy that assumes the worst in each period and optimizes against that when this model is compared to a model with completely observable wealth levels the following insights are obtained 1 there is over saving 2 investment and output processes are more volatile than consumption and 3 regressions underestimate the risk aversion of agents information about the wealth or stock level is only valuable if it alters the support of the agent s beliefs thus information may be statistically informative yet economically valueless if information changes the support of the agent s beliefs then the optimal solution features an endogenous resource discovery process

using a choice experiment to account for preference heterogeneity in wetland attributes the case of cheimaditida wetland in greece abstract this paper aims to assist policy makers in formulating efficient and sustainable wetland management policies in accordance with the ramsar convention and the european union water framework directive 2000 60 ec by providing results of a valuation study on the cheimaditida wetland in greece a choice experiment is employed to estimate the values of changes in several ecological social and economic functions that cheimaditida wetland provides to the greek public in addition to the conditional logit model a random parameter logit model a random parameter logit model with interactions and a latent class model are estimated to account for heterogeneity in the preferences of the public for the various functions of the wetland the results reveal that there is considerable preference heterogeneity across the public and on average they derive positive and significant values from sustainable management of this wetland the estimated economic benefits of sustainable wetland management are weighed against the costs of alternative wetland management scenarios results of this cost benefit analysis can aid in the design of socially optimal policies for sustainable management of the cheimaditida wetland with possible implications for other similar wetlands in greece and the rest of europe

fisheries instrument choice under uncertainty this paper uses data from an actual fishery to construct a tractable dynamic model to compare expected profit and its variance optimal stock size optimal harvest rate and optimal fishing effort under different management regimes under uncertainty the results provide a comparison of instrument choice between a total harvest control and a total effort control under uncertainty an original method to evaluate the tradeoffs between profits and other criteria in a dynamic context and insights regarding the relative merits of catch and effort controls in fisheries management

landing fees vs harvest quotas with uncertain fish stocks a revised version of this paper was published in the journal of environmental economics and management volume 43 issue 2 march 2002 pages 325 338

ecoviability for small scale fisheries in the context of food security constraints this paper applies a stochastic viability approach to a tropical small scale fishery offering a theoretical and empirical example of ecosystem based fishery management approach that accounts for food security the model integrates multi species multi fleet and uncertainty as well as profitability food production and demographic growth it is calibrated over the period 2006 2010 using monthly catch and effort data from the french guiana s coastal fishery involving thirteen species and four fleets using projections at the horizon 2040 different management strategies and scenarios are compared from a viability viewpoint thus accounting for biodiversity preservation fleet profitability and food security the analysis shows that under certain conditions viable options can be identified which allow fishing intensity and production to be increased to respond to food security requirements but with minimum impacts on the marine resources

decentralized regulation of a common property renewable resource industry with irreversible investment abstract the effectiveness of output controls for rationalizing a common property renewable resource has been called into question by the theoretical work of j r gould economica nov 383 402 1972 a proper examination of this question requires an intertemporal analysis one that takes into account that asymmetries between persistent factors of production immaleable capital and factors that are instantaneously consumed labor or ldharvest effort we present here a nonlinear intertemporal model of a renewable resource industry under conditions of irreversible capital investment and undertake to analyze its dynamics both at open access and under centralized optimal management we then examine the theoretical possibility of decentralized regulation by pigouvian taxes and reconsider the proposition of gould

discrete modelling of supply response under uncertainty the case of the fishery abstract in the absence of complete control in a regulated industry effective management requires prediction of firms behavioral responses to public policy this paper develops a discrete choice model of supply response under uncertainty and applies it to fishery choice problems of new england fishing firms while fishermen demonstrate a bias towards remaining within the same fishery sufficient incentives in terms of changes in expected returns and risk are shown to elicit response due to extreme uncertainty concerning population dynamics of fish stocks a satisficing approach to management facilitated by this type of modelling may be more appropriate than bioeconomic optimization

a stochastic viability approach to ecosystem based fisheries management academia and management agencies show a growing interest for ecosystem based fishery management ebfm however the way to operationalize this approach remains challenging the present paper illustrates how the concepts of stochastic co viability which accounts for dynamic complexities uncertainties risk and sustainability constraints can be useful for the implementation of ebfm in the present case this concept is used to identify fishing strategies that satisfy both ecological conservation and economic sustainability in a multi species multi fleet context economic viability analysis eva and the broader co viability analysis cva are proposed to expand the usual population viability analysis pva and precautionary approach an illustration is proposed using data on the fisheries of bay of biscay france exploiting the stocks of nephrops and hake stochastic simulations show how cva can guarantee both ecological stock and economic profit sustainability using 2008 as a baseline the model is used to identify fishing efforts that ensure such co viability c 2012 elsevier b v all rights reserved

an expected profit model for monetizing fishing location choices abstract we develop and analyze the properties of a new type of discrete choice model which jointly estimates the expected value of catch and location choice this model implicitly monetizes location choices and can be used to predict costs and effort redistribution of creating marine protected areas or of implementing other policy changes that either increase travel costs or alter expected revenue we illustrate our approach by considering the closing of the steller sea lion conservation area in the united states bering sea to pollock fishing

coalition formation in fisheries with potential regime shift a system can undergo rapid regime shift in which the growth of natural resources suddenly and permanently declines we examine how the threat of such a shift alters the strategic management of a common pool renewable resource we consider exogenous and endogenous threats and examine their effects on both incentives to join a coalition and harvest decisions we find that an exogenous threat of reduced resource growth may cause the coalition to grow in size and perhaps of most interest we identify conditions under which members of the stable coalition reduce harvest while non members increase harvest in response to the threat in contrast an exogenous threat of total stock collapse may destabilize coalitions resulting in higher harvest from former members but reduced harvest by non members when the threat of either type of shift is endogenous the threat of regime shift can induce stable coalitions with more than two members in particular we identify cases in which the first best full cooperation is sustained as an equilibrium outcome finally we find that the relation between the magnitude of the shift and the size of stable coalitions may be negative

measure twice cut once optimal inventory and harvest under volume uncertainty and stochastic price dynamics abstract natural resources are often subject to state uncertainty resource abundance is not known with certainty but can be measured measurements are typically imperfect and costly to obtain the decision of whether to invest in resource measurement may be influenced by other state variables for example a resource commodity price we introduce a mixed observability model of optimal forest management featuring a partially observable forest resource and perfectly observable stochastic price the decision maker optimizes the expected net present value of forest returns by choosing when to measure current forest volume conduct an inventory harvest and replant or delay action parameter values are obtained from numerous forestry data sources optimal investment in inventory reduces the cost of uncertainty about timber volume and increases the predictability of returns moreover price stochasticity interacts with inventory decisions to produce asymmetric effects of high and low prices on inventory timing we also produce the first graphical faustmann rule analogues for jointly optimal inventory and harvest

increasing marginal returns and the danger of collapse of commercially valuable fish stocks abstract on the basis of data from the north sea herring fishery we discuss the consequences of increasing marginal returns on the exploitation of renewable resources we show that high but still reasonable discount rates can cause extinction to be optimal even in the ideal case of a sole owner and a resource with a high growth rate in the case of lower discount rates optimal cyclical policies can periodically drive the resource to levels approaching safe minimum standards we discuss the sustainability intergenerational equity social risk aversion and theoretical issues raised by increasing marginal returns