Investing in natural capital as management strategy in fisheries: The case of the Baltic Sea cod fishery

Many of today's fish stocks are officially managed following the precautionary approach. Yet, different political objectives and uncertainties among fishermen about their economic future make its implementation difficult. Over 75% of all commercially valuable stocks are exploited, overused, or collapsed and in a state of recovery [FAO, 2004. The state of the world fisheries and aquaculture. FAO, Rome. Managing fish stocks with an ecosystem-based approach is likely to stop the divestment of natural capital by combining sustainable use strategies with the preservation of marine ecosystems. Using the example of the Baltic Sea cod fishery, we show that a recovery program is economically and ecologically viable and reduces negative externalities. While policy makers must assist fishermen during the early years of the program, fishermen will experience greater landings and profits in subsequent years.     

Methods for Environmental and Economic Accounting for the Exploitation of Wild Fish Stocks and their Applications to the Case of Icelandic Fisheries

The paper discusses methods for estimating the value of commercially exploited fish stocks and the cost of exploiting them. Methods which are recommended in the System of National Accounting (SNA) satellite system and the System for Integrated Environmental and Economic Accounting (SEEA) and relevant for this task are discussed. The paper questions the relevance of some of these methods. It argues for the integration of economic accounting for wild fish stocks with estimation of efficient management of them. Using biological and economic data makes it possible to produce consistent estimates of the value of fish stocks and the cost of exploiting them. These estimates are useful for national accounting and for guiding management of fisheries. This method allows estimation of the cost of inefficiency of fisheries management besides estimation of the cost of depletion. The different methods are illustrated using data on commercial fisheries in Iceland and the fish stocks that they exploit. It is shown that even if all methods are based on market valuation and use only objective data they lead to very different outcomes.     

Embodiment, productivity, and the age distribution of capital

An important theme in modern research on productivity has been that technological progress may be embodied in capital in the sense that traditional measures of TFP growth reflect unmeasured improvements in the quality of capital inputs as well as pure disembodied technological progress. It is commonly believed that an implication of this embodiment hypothesis is that there should be a negative relationship between measured TFP and the age of the measured capital stock. This paper presents empirical evidence which suggests that an increase in the age of the capital stock is actually associated with higher TFP growth. This surprising result may be due to the presence of a mis-measurement normally overlooked in this literature: With mis-measured improvements in capital quality, the usual depreciation rates used to construct empirical capital stocks are incorrect for growth accounting. This effect dominates the usual average age effect.     

Market integration between wild and farmed seabream and seabass in Spain

Gilthead seabream (Sparus aurata) and European seabass (Dicentrarchus labrax) production from aquaculture has been increasing since the 1990s. Nowadays, about 95% of their production comes from aquaculture. In this study, we analyse if the rapid growth in the aquaculture production of both species has affected the capture fisheries prices of both species. In other words, we investigate if there is market integration between wild and farmed gilthead seabream and European seabass. In order to do this analysis, we use data from the main gilthead seabream and European seabass markets in Spain. The results show that there is no market integration between wild and farmed gilthead seabream and European seabass. This implies that capture fisheries are not affected by increases in the aquaculture production of both species. But gilthead seabream and European seabass aquaculture producers face a smaller demand that explains the difficulties this aquaculture segment is facing.     

我国对外直接投资的逆向技术外溢——以国有大型企业为例的实证

本文以我国100家国有大型企业为研究样本,采用面板数据模型,分别检验了对外直接投资与投资企业人力资本积累、技术创新绩效的相关性。结果表明,企业的人力资本密集度与其境外资产存量的相关性不显著,但技术创新绩效与境外资产存量显著正相关。这说明我国国有企业对外直接投资的逆向技术外溢效应主要表现为物化技术溢出而不是非物化技术溢出。基于此,建议积极引导我国企业优化对外投资结构,加大对国外研发密集型产业和技术创新活跃地的直接投资,充分发挥海外机构或研发基地在技术吸纳和人才培养方面的双重作用,促进企业提高自主创新能力,加快自主创新步伐。     

GLOBAL POPULATION GROWTH,TECHNOLOGY, AND MALTHUSIAN CONSTRAINTS: A QUANTITATIVE GROWTH THEORETIC PERSPECTIVE

We structurally estimate a two‐sector Schumpeterian growth model with endogenous population and finite land reserves to study the long‐run evolution of global population, technological progress, and the demand for food. The estimated model closely replicates trajectories for world population, GDP, sectoral productivity growth, and crop land area from 1960 to 2010. Projections from 2010 onward show a slowdown of technological progress, and, because it is a key determinant of fertility costs, significant population growth. By 2100, global population reaches 12.4 billion and agricultural production doubles, but the land constraint does not bind because of capital investment and technological progress.     

Revolution,tribalism, and the Cheshire cat: Three paths from now

Examination of the time course of the change in numbers of experimental populations of mice, and of the world population of man, reveals abrupt and apparently irreversible phase changes in the processes governing population dynamics. Such phase changes can lead to extinction of the population or to opening up a new era of evolution. For the past 43,000 years each successive doubling of human world population has required only half the time as the prior doubling. Continuation of this process of population increase will shortly lead to extinction of man as a species. This course is the “Cheshire cat” path, during which each individual becomes less aware of less and less as numbers of individuals exceed the upper optimum. Beyond this nonchoice of future direction there are two major options. First, we can intentionally establish a new world tribalism characterized by zero population growth accompanied by a pervading traditionalism that establishes invariant patterns of social, technological, and ideational function. Second, we can choose to design further evolution (Revolution) with emphasis on continuing to expand individual potentiality or capacity. This path will require a continuing decline of world population accompanied by an increase in the effectiveness of technological prostheses for information processing beyond that possible by biological and social brains.     

Scale Effects,Savings and Factor Shares in a Human Capital-based Growth Model with Physical Capital Accumulation

Using a balanced-growth model with physical and human capital accumulation, we analyze quantitatively the long-run effects of changes in the savings rate and in income distribution (i.e. the shares of physical and human capital in income) on investment in skill acquisition, income growth, and the ratio of human to physical capital. In the long run, the ratio of physical to human capital is constant, so that these two factor inputs can grow at the same rate. This rate is a function of the economy's exogenous technological and preference parameters and depends positively on the share of skills invested in human capital formation. We also find that population growth is neither necessary nor conducive to economic growth, that the level of real income depends linearly on the level of human capital and that it is independent of population size.     

Fishing Revenue, Productivity and Product Choice in the Alaskan Pollock Fishery

A key element in evaluating fishery management strategies is examining their effects on the economic performance of fishery participants, yet nearly all empirical studies of fisheries focus exclusively on the amount of fish harvested. The economic benefits derived from fish stocks involve the amount of revenue generated from fish processing, which is linked to both the way fish are harvested and the products produced from the fish. In this study we econometrically estimate a flexible revenue function for catcher-processor vessels operating in the Alaskan pollock fishery, recognizing potential endogeneity and a variety of fishing inputs and conditions. We find significant own-price supply responses and product substitutability, and enhanced revenues from increased fishing days and tow duration after a regulatory change introduced property rights through a new fishing cooperative. We also find significant growth in economic productivity, or higher revenues over time after controlling for observed productive factors and price changes, which exceeds that attributable to increased harvest. These patterns suggest that the move to rights-based management has contributed significantly to economic performance in the pollock fishery.     

Sustainable per capita consumption under population growth

We establish two investment rules for maximal constant per capita consumption under exogenous population growth, one in terms of total capital stocks and the other in terms of per capita capital stocks. Both rules show the importance of the development of future population growth. The investment rules are illustrated in the one-sector model of capital accumulation, the DHSS model of capital accumulation and resource depletion, and the Stollery–d’Autume–Schubert model in which natural capital provides amenities. Application to recent empirical evidence indicates that actual genuine savings might be insufficient to sustain per capita consumption, when future population growth is combined with a large per capita consumption-wage gap.     

Stochastic accumulation of human capital and welfare in the Uzawa–Lucas model: an analytical characterization

Stochastic growth models are often solved numerically, because they are not tractable in general. However, recent several studies find the closed-form solution to the stochastic Uzawa–Lucas model in which technological progress or population dynamics follow a Brownian motion process with one or two parameter restriction(s). However, they assume that the return on the accumulation of human capital is deterministic, which is inconsistent with empirical evidence. Therefore, I develop the Uzawa–Lucas model in which the accumulation of human capital follows a mixture of a Brownian motion process and many Poisson jump processes, and obtain the closed-form solution. Moreover, I use it to examine the nexus between human capital uncertainty, technological progress, expected growth rate of human capital, and welfare.     

A model for estimating fish population and optimal fishing effort in lakes and rivers

We developed a model for estimating the fish population for various species in lakes and rivers. Our estimation focuses, in its first step, on fish species that breed outside the lake. Using the annual outside supply of fingerlings, natural survival rate and reported amounts of fish caught, we estimated fish stock. Given the estimated stock for fish bred outside the lake, we can evaluate the catch rate. Assuming equal catch rates for other species, and given the amount caught for each species, we are able to evaluate each species stock. Using the proposed technique, we evaluated various species stocks in the Sea of Galilee (Lake Kinneret) in Israel. Using our suggested technique for evaluating fish stock, we calculated the optimal effort of fishing needed for maximizing steady state profit of the fishers.     

Optimum reserve size,fishing induced change in carrying capacity,and phenotypic diversity

Fish stocks around the world are heavily overexploited in spite of fishing policies in several parts of the world designed to limit overfishing. Recent studies have found that the complexity of ecological systems and the diversity of species, as well as negative impact of fishing activities on environmental carrying capacity of fish stocks—all contribute to the problem. A number of biologists, managers, and practitioners strongly support the use of marine reserves as a management strategy for marine conservation. This paper contributes to this line of research by seeking an optimum reserve size and fishing effort for situations where species diversity decrease at fishing grounds and fishing activities impact carrying capacity. We found that a reserve size which maximizes economic rents could ruin a fish stock if fishing impacts are not accounted for. On the other hand, the reserve serves as a bifurcation term which could improve the resilience of a marine ecosystem.     

科技人力资源对区域经济增长贡献的实证研究——基于省级尺度的分析

本文在经典的柯布-道格拉斯函数的基础上,扩展了生产要素,测算了各个省市的科技人力资源对经济增长的贡献率。研究表明:劳动力对经济增长的贡献主要体现在科技人力资源上,普通从业人员对经济增长的贡献率较低;中部主要省份的科技人力资源在近10年获得了较快的发展,对经济增长的贡献逐步提高;某些省市的科技人力资源没有得到充分利用,对经济增长的贡献很小甚至为负,存在着一定程度的人员浪费现象;在科技人力资源发挥作用较小的省市中,能源和资本依然是两个最重要的促进经济增长的要素,其中水资源逐步成为制约经济增长的一个重要因素。     

ENDOGENOUS HUMAN CAPITAL INVESTMENT AND THE INTERACTION OF FRONTIER AND ADOPTIVE KNOWLEDGE ON GROWTH AND WAGE INEQUALITY

A three-sector, overlapping-generations growth model endogenizes the opportunity cost of human capital formation and the relative skill requirements of invention, innovation, and adoption of general-purpose technologies. As a result, the relative wage of skilled workers is a function of the endogenous ratio of total-to-adoptive knowledge (where the difference in knowledge stocks is frontier knowledge). Comparative statics are examined for the model's seven parameters. Simulations (representing a transition with phases to a more complex level of economic development) are presented for simultaneous exogenous shocks capable of matching (i) observed inverse movements of the relative wage and the detrended relative supply in the USA, (ii) the sharp slowing and recovering US multifactor productivity growth data since the 1970s, and (iii) a reconciliation of data used to support or deny skill-biased technological change as a major force driving up the relative wage since 1980.     

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.     

Genetics, family structure, and economic growth

Recent biomedical research shows that roughly three-quarters of cognitive abilities are attributable to genetics and family environment. This paper presents a growth model that characterizes the role of the intergenerational transmission of genes and the effect of family environment on growth trajectories. If the average human or physical capital stocks are sufficiently low, the model shows that the economy will be caught in a poverty trap. Conversely, countries with more resources will converge to a bala nced growth path where the average rate of genetic transmission of skills from parents to children determines the long-run rate of output growth. Increased genetic diversity (or income inequality) is shown to raise the fertility rate and reduce output growth in the transitional dynamics. Thus, nature and nurture are able to explain a variety of countries' growth experiences.     

The effects of water temperature in aquaculture management

This study examines the impact of water temperature on the optimal management of the ration size and fish weight in off-shore farm aquaculture. A model for the expected returns of the farm is developed which includes a fish growth function influenced by fish weight, the ration size and water temperature. The output transportation cost has an ambiguous effect on the harvesting size, but the impact of water temperature is positive. These results explain empirical evidence in the Canary Islands that unfavourable economic conditions could be overcome by environmental advantageous conditions raising productivity.     

What really matters: Discounting, technological change and sustainable climate

This paper discusses the interplay between the choice of the discount rate, greenhouse gas mitigation and endogenous technological change. Neglecting the issue of uncertainty it is shown that the Green Golden Rule stock of atmospheric carbon is uniquely determined, but is not affected by technological change. More generally it is shown analytically within the framework of a reduced model of integrated assessment that the optimal stationary stocks of atmospheric carbon depend on the choice of the discount rate, but are independent of the stock of technological knowledge. These results are then reinforced numerically in a fully specified integrated assessment analysis.     

The systems dynamics of endogenous population growth in a renewable resource-based growth model

This paper evaluates the dynamic effects of adding an endogenous process for human population growth into a renewable resource-based economic growth model. Endogenizing human population growth in a static, constant technology form of the model gives rise to a dynamically complex system, with the possibility of multiple steady states of several types, and unusual comparative static responses to changes in the system's parameters. Adding technological progress to the model gives rise to the possibility of multiple sustainable paths for the variables in the system. These results reinforce concerns raised by ecological economists about systems stability and sustainability, since exogenous shocks to the system could move the economy from higher welfare to lower welfare equilibria or, in the model with technological progress, from higher welfare to lower welfare sustainable growth paths. Moreover, this kind of dynamic complexity adds to the management challenge faced by policy makers, who could confront the necessity of maneuvering the economy among different equilibria or sustainable growth paths.