Valuation and Management of Fishing Resources Under Price Uncertainty

The traditional expected-net-present-value methods cannot properly capture the management flexibility and strategic value aspects of a fishery, and may understate its value. Instead, this paper develops a Real Options model to conceptualize and evaluate fishery exploitation flexibility. Specifically, general models to value the opportunity to either exploit or invest in a fishery are presented. They suffice to determine not only these values, but also the optimal policy for opening, closing, delaying and setting its harvest rate. The sustainable case in which the harvest rate equals the natural net growth function is also considered. Concerning the exploitation decision, it is found that, as could be expected, the higher the resource price the higher the value of this opportunity in both models (general and sustainable). However, the resource stock affects both models differently. As to the investment opportunity, its value is always lower than the exploitation opportunity because of investment costs. Finally, numerical simulations are run in order to illustrate the nature of the solution. Sensitivity analysis concerning the influence of the tax rate, convenience yield, risk-free interest rate and price volatility on the value of the fishery is also reported. Earlier versions of this paper have benefited from conference participants at the Young Economists Conference 2000 (Oxford University), Tenth Biennial Conference of the International Institute of Fisheries Economics and Trade (Oregon State University), XXV Simposio de Análisis Económico (Universidad Autónoma de Barcelona, Spain) and Seminar at the Dpt. Fundamentos del Análisis Económico (Universidad del País Vasco, Spain). We especially thank Prof. Ian Bateman and two anonymous referees whose insightful comments have enabled us to eliminate several errors and to improve the presentation. Murillas gratefully acknowledges doctoral fellowship from Ministerio de Educación y Ciencia (AP96), and financial support from the Xunta de Galicia (PGIDT01PXI30004PR) and from the Ministerio de Ciencia y Teconología (SEC 2001-3700). The usual disclaimer applies.     

Selectivity, Pulse Fishing and Endogenous Lifespan in Beverton-Holt Models

Optimal management in a multi-cohort Beverton-Holt model with any number of age classes and imperfect selectivity is equivalent to finding the optimal fish lifespan by chosen fallow cycles. Optimal policy differs in two main ways from the optimal lifespan rule with perfect selectivity. First, weight gain is valued in terms of the whole population structure. Second, the cost of waiting is the interest rate adjusted for the increase in the pulse length. This point is especially relevant for assessing the role of selectivity. Imperfect selectivity reduces the optimal lifespan and the optimal pulse length. We illustrate our theoretical findings with a numerical example. Results obtained using global numerical methods select the optimal pulse length predicted by the optimal lifespan rule.     

市场不确定性与股票流动性——基于共性和微观结构的视角

市场不确定性与股票流动性有何联系?该联系受哪些因素影响?本文充分考虑内幕交易者的特征,为两者构建了理论模型,并结合沪深A股的数据证实:(1)市场不确定性越大,持股的风险越高,这降低了投资者的交易意愿,对流动性造成负面影响;(2)大宗交易制度将常规交易与大宗交易分离,减小了市场不确定性对个股的冲击,使"不确定性—流动性"关系减弱;(3)融资融券为资金或头寸短缺者提供了交易的可能,因此个股受不确定因素的影响更大,"不确定性—流动性"关系更强。文章为"当局积极干预证券市场、维持市场稳定"提供了政策依据。     

The Causal Relationship between Economic Policy Uncertainty and Stock Market: A Panel Data Analysis

This study applies recently developed bootstrap panel Granger causality, proposed by Kónya, to investigate a causal link between economic policy uncertainty and stock markets in nine countries over monthly periods from 2003M01 to 2014M12 (Kónya (2006 Kónya, L. (2006). Exports and growth: Granger causality analysis on OECD countries with a panel data approach. Economic Modelling, 23, 978–992. doi: 10.1016/j.econmod.2006.04.008[Crossref], [Web of Science ®] , [Google Scholar]) Exports and growth: Granger causality analysis on OECD countries with a panel data approach. Economic Modelling, 23, 978–992). The modeling allows us to examine both the cross-sectional dependency and the country-specific heterogeneity. The empirical results indicate that not all countries are alike, and that the theoretical prediction that stock markets fall at the announcement of a policy change is not always supported. Specifically, this work finds evidence of the stock market leading hypothesis for India, Italy, and Spain, while the economic policy uncertainty leading hypothesis cannot be rejected for the United Kingdom. In addition, the neutrality hypothesis was supported in the remaining countries (Canada, China, France, Germany and the United States), while the feedback hypothesis, however, is not found. The findings of this study could provide important policy implications for these nine countries.     

Portfolio Fishing

The optimal fishing pattern in a multi-cohort fishery is determined using risk theory.Portfolio theory becomes applicable by treating different age groups of fish as different assets. A possibility set is derived using data on Icelandic cod fisheries. In the presence of risk aversion, it is shown that the abrupt behavior found in deterministic models is changed towards a smoother fishing pattern. The historical selection pattern for the Icelandic cod stock is shown to be near optimal using a maximal effort-type cost function, but historical levels of effort are inefficient and lead to less profit and greater fluctuations than implied by profit or utility maximization.     

经济不确定衡量及对股票市场的影响——基于网络信息检索技术

基于网络信息检索频率的基础上,提出了一种新的衡量经济不确定程度的方法。文章的研究动机来自于经济心理学的研究成果,即经济主体往往会通过信息检索的增加来反映不确定程度的增加。网络信息检索的优点主要体现在检索面广和即时性上,并且与文字相比,网络信息检索更能够客观地反映人们的行为。研究结论显示,以网络信息检索为基础的衡量经济不确定程度的方法与其他若干相关指标相比具有明显的优势,并且这种方法与整个股票市场的收益率和波动率都有着紧密的联系。     

股权性质、环境不确定性与技术资本配置效率

技术转化为资本,资本创造价值已经成为共识,技术资本在不同公司创造价值的作用程度不同,根源是技术资本配置效率问题。选取沪深两市2008-2013年间制造业上市公司为样本,检验了基于不同股权性质的公司环境不确定性对企业技术资本配置效率和价值的影响,研究结果表明：①企业环境不确定性程度越高,技术资本配置效率越低,并且技术资本配置偏离度在国有公司中表现为配置过度,在非国有公司表现为配置不足;②在股权性质为国有的公司中,由环境不确定性引发的技术资本配置偏离将降低企业价值,在非国有控股公司中,由环境不确定性导致的技术资本配置偏离将增加企业价值。     

Fishing for Discrimination

The use of bogus, unsolicited job applications with the intention of measuring employment discrimination extends across 30 years and six countries. Preferential treatment of male applicants has been detected in Departments of Psychology in U.S. universities. Such investigations have also detected a relative disinclination to hire homosexuals in Ontario law firms, Turkish workers in Germany, older job applicants in the U.S.A., and the disabled in France. Many of these studies dispatched only a single application to employers; consequently they are a test of 'preferential treatment', rather than discrimination.     

关于全民炒股和股市泡沫的经济分析

近来媒体关于全民炒股特别是上班族炒股升温的报道,敲响了股市泡沫崩溃的警钟,而推动股市泡沫走向崩溃的,则是全民炒股热和上班族炒股风.中国股票市场的两大缺陷是中国股市动辄形成严重泡沫的重要原因,要彻底消除股市泡沫,必须改变股票供给严重不足和股票需求异常增大的局面,并严肃八小时工作纪律,杜绝全民炒股特别是上班炒股风.在股市钱空的程度日趋严重的形势下,对股市泡沫崩溃及其严重影响必须有清醒的认识,做好充分的准备.     

通货膨胀与农业股票收益多尺度分析

通货膨胀水平与股票收益率的关系是金融学研究的热点问题之一。文章介绍了小波方法的多尺度分析原理,采用农林指数月度收盘价的对数收益率和消费者价格指数分别代表农业股票收益率和通货膨胀率的水平,得到2007年9月到2012年12月农业股票收益率和通货膨胀率的统计特征。以小波方法分解已知的时间序列,得到不同尺度的数值,利用最小二乘法实证两者之间的关系,得到在中尺度和大尺度的分析周期上,两者具有统计意义上显著地正相关关系,支持了费雪效应假说。而在短尺度分析周期上,两者又具有统计意义上的负相关性,出现了费雪效应悖论。     

Fishing Technology and Optimal Distribution of Harvest Rates

This paper examines the problem of the optimal management of a joint-ownership fishing exploitation, where agents use different fishing gears. We consider a model in which the fishing activity may affect resource growth, not only through the harvest function but also through the natural growth rate of the resource. This allows us to capture the fact that some fishing gears alter the natural growth rate of the resource. We find that when the natural growth of the resource is altered by the fishing technology, the optimal stock is not independent of how harvest quotas are distribute among the agents. As a result, a fishing policy that firstly determines the optimum stock and, secondly, decides how to distribute the harvest among the different agents, will not be efficient. We also analyze the joint determination of optimal stock and harvest quotas and show that positive harvest quotas will only be optimal when countries are characterized by certain asymmetries.     

Stock Returns and Inflation

In this paper the relationship between inflation and stock returns in Australia is examined. It is found that increases in the price level reduce the real level of the stock price index. However, it is also found that the question of whether persistent increases in inflation affect real returns cannot be addressed using the Australian data.     

The Behavioral Ecology of Fishing Vessels: Achieving Conservation Objectives Through Understanding the Behavior of Fishing Vessels

Environmental and Resource Economics - Colin Clark made seminal contributions in both resource economics and behavioral ecology. In the former, he showed how to link biological and economic factors...     

Stock and flow sampling

This letter is concerned with the joint distribution of variables that effect the duration of stay in a given state, for example, unemployment. It deals with the difference in the joint distribution between the population of residents of the state—the stock—and the population of entrants or leavers—the flow, and with the implications of this difference for econometric inferences.     

Uncertainty and entry deterrence

Summary. We study a model where capacity installation by an incumbent firm serves to deter others from entering the industry. We argue that uncertainty about demand or costs forces the incumbent to choose a higher capacity level than it would under certainty. This higher level diminishes the attractiveness of deterrence (Proposition 1) and, therefore, the range of parameter values for which deterrence occurs (Proposition 2). Received: July 10, 1997; revised version: November 21, 1997     

Uncertainty and Production Quotas

This paper examines the role of uncertainty in determining the impact of production quotas on a risk-neutral producer's behaviour
In the context of production uncertainty the introduction of a quota will lead to a reduction in planned production. Moreover, in a situation of an established quota, the level of planned production relative to the quota depends both on the size of the profit margin on quota production and on the extent of production uncertainty. Apart from these direct influences, uncertainty influences planned production indirectly in a situation where over-quota production can be sold in an uncertain export market. The direction of this influence depends on the relationship between the producer's uncertainties of price and production. It is argued, therefore, that the welfare assessment of the impact of production quotas must incorporate the role of uncertainty.     

Uncertainty and Investment Dynamics

This paper shows that with (partial) irreversibility higher uncertainty reduces the responsiveness of investment to demand shocks. Uncertainty increases real option values making firms more cautious when investing or disinvesting. This is confirmed both numerically for a model with a rich mix of adjustment costs, time-varying uncertainty, and aggregation over investment decisions and time and also empirically for a panel of manufacturing firms. These "cautionary effects" of uncertainty are large—going from the lower quartile to the upper quartile of the uncertainty distribution typically halves the first year investment response to demand shocks. This implies the responsiveness of firms to any given policy stimulus may be much weaker in periods of high uncertainty, such as after the 1973 oil crisis and September 11, 2001.     

Uncertainty and Climate Change

Uncertainty is pervasive in analysis of climatechange. How should economists allow for this? And how have they allowed for it? This paperreviews both of these questions.