Input Controls,Input Substitution and Profit Maximisation in the English Channel Beam Trawl Fishery

Studies of input substitution in fisheries have tended to focus on substitution between physical inputs and/or time fished. However, input controls may create incentives for substitution of other inputs into the production process. For example, fishers faced with constraints on access to particular areas of the fishery may substitute physical inputs for fishing location. This was the case with the UK beam trawl fishery in the English Channel. Constraints were imposed on access to particular areas of the fishery through restrictions on engine power. This created incentives for a number of fishers to reduce their engine power to meet the conditions of the input control. The relative contribution of the boat inputs and location in the production process and the potential for substitution were examined using a translog production function. The results suggested that the apparent input substitution was consistent with profit maximising behaviour.     

Irrigation Externalities and Agricultural Sustainability in South‐eastern Nigeria

Agricultural intensification by irrigation is increasingly regarded as the key to solving food supply problems in Sub‐Saharan Africa. Conversely, mounting empirical evidence suggests that irrigation externalities might preclude long‐term sustainability of arable agriculture. Choosing between intensive irrigation schemes and less intensive farming systems is therefore, problematic. The paper examines the implications of irrigation intensification in south‐eastern Nigeria using adjacent rain‐fed farms as the counterfactual. The analyses found mixed results. When first introduced, the irrigation scheme increased marginal factor productivity and gross margins but this has subsequently declined to the extent that the marginal factor product of land has become negative. The annual yields of the irrigated farms were also less stable than those of the less intensive rain‐fed farms. These results indicate the dilemma that irrigation externalities present to sustainable agricultural policy and suggest a need to look again at the potential for developments in rain‐fed systems.     

Language–Related Differences in a Contingent Valuation Study: English versus Spanish

To test the similarity of English– and Spanish–speaking households responses to a contingent valuation survey, phone interviews were conducted in both languages regarding two forest fire prevention programs. While there were similar response rates, there were significant differences in the most frequent reasons given for refusing to pay. In the pooled logit model, the language intercept and bid interaction variables were insignificant in both programs. The likelihood ratio test of separate logit equations showed no statistical difference between English– and Spanish–speaking households responses to either program. Mean benefits reported by Spanish–speaking households were about one–third lower than English–speaking households, although the difference is not statistically significant.     

水产科技资源在不同领域优化配置的评价标准研究

本文通过阐述水产科技资源优化配置标准选择的重要意义对选题进行必要的背景介绍，通过构造经济领域、科学领域中的科学与技术“坐标”，提出水产科技资源在科学领域和经济领域存在不同的优化配置标准的理论假设，在此基础上进一步分析了科学领域和经济领域中水产科技资源的优化配置标准。     

Horticulture,livelihoods, and urban transition in Africa: evidence from South‐West Cameroon

This article documents change in periurban horticulture using repeat surveys in 1995 and 2004 of about 300 households around Muea, Cameroon. Real household incomes increased by 14%, with a large shift from farm to nonfarm income. Within agriculture, activity shifted from staple crops to horticulture, both for sale and in home consumption. In 1995, there were large remittances from farmers involved in periurban horticulture to their village of origin; in 2004 remittances continued and horticultural farmers were also heavily involved in informal financial associations. Periurban horticulture is disproportionately practiced by women and older workers, and plays an important and growing role in African livelihoods.     

关于渔业科技前瞻性探讨

近十余年来,浙江温州市水产业发展迅速,特别是海水养殖已经成为发展最快的食品生产行业。 今后渔业要获得更成功的发展,首先要提高渔业生产的科技含量,其次在确保生产效益、产品质量的同时,必须考虑环境保护问题,正确处理生产发展和环境保护之间的关系。为了使渔业生产持续健康发展,在渔业科技方面应加强以下几个方面的工作。 1． 养殖容量研究 养殖容量研究是一个多学科的课题,也是一个基础性的课题,只有知道养殖容量才能合理开发利用养殖区域,保证养殖区域的生态平衡。养殖业发达的国家,十分重视这方面工作,对养殖区域的使用…     

External and Internal R&D,Capital Investment and Business Performance in the Spanish Agri‐Food Industry

We examine the effects of external and internal expenditure on research and development on the business performance of industrial agri‐food enterprises. For this purpose, a data sample from the Encuesta de Estrategias Empresariales en España (Survey of Business Strategies in Spain) was used, which includes information on more than 400 businesses over the period 2000–2008. The econometric analysis uses quantile regressions to address the vast asymmetry of the variables and to identify non‐linear relationships. The results reveal interesting new findings on the impacts of R&D on the agri‐food industry. The most evident, although not the most immediately apparent, relationship concerns the positive effects of external R&D on business performance. Internal R&D was also revealed to be an important way of enhancing the productivity of SMEs. In addition, the modernisation of the production process through investment in capital goods continues to be the main path to improve competitiveness. However, support was found neither for the inverse relationship, that is the most profitable firms are those that spend the most on R&D, nor for complementarity between external and internal R&D. The latter would imply that the bulk of Spanish agri‐food firms have at most the capacity for only one type of R&D.     

Valuing the Willingness‐to‐Pay for Sustainable Seafood: Integrated Multitrophic versus Closed Containment Aquaculture

Awareness of the environmental problems associated with conventional finfish aquaculture has stimulated interest in more sustainable production methods. For example, integrated multitrophic aquaculture (IMTA) combines the culturing of fish and extractive aquaculture species at one site to simulate a balanced natural system. In contrast, closed containment aquaculture (CCA) separates farming from the natural marine environment using closed water tanks on land or in water. We explore consumer preferences for salmon produced with IMTA or CCA rather than conventional technology and pose two questions: how aware of IMTA and CCA are salmon consumers on the U.S. West Coast and what are they willing to pay for salmon produced with these methods? Using a discrete choice experiment, we estimate marginal willingness‐to‐pay of 39.0% and 15.7% for IMTA and CCA, respectively, as a premium added to the price of conventionally farmed Atlantic salmon. Results using latent class analysis show that consumers with a strong preference for wild salmon have high marginal values for farmed salmon produced with IMTA or CCA, but the average consumer from this group would be unlikely to purchase it. Overall, 44.3% and 16.2% of the respondents preferred IMTA or CCA to conventional salmon farming, respectively, and IMTA was preferred to CCA when respondents were asked to choose one. La sensibilisation aux problèmes environnementaux liés à l’élevage de poissons classique suscite un intérêt pour des méthodes de production plus durables. Par exemple, l'aquaculture multitrophique intégrée (AMTI) combine l’élevage de poissons et d'espèces d'extraction sur un même site afin d'imiter un écosystème naturel équilibré. En revanche, l'aquaculture en parc clos (APC) consiste en un élevage hors du milieu marin naturel à l'aide de réservoirs étanches installés sur le sol ou dans l'eau. Dans la présente étude, nous avons analysé les préférences des consommateurs pour le saumon issu de l'AMTI ou de l'APC et celui issu de l’élevage classique. Nous nous sommes également posé deux questions : À quel point les consommateurs de saumon de la côte Ouest des États‐Unis connaissent‐ils l'AMTI et l'APC, et combien sont‐ils prêts à payer pour obtenir du saumon issu de ces méthodes de production? À l'aide de la méthode des choix discrets, nous avons obtenu un consentement à payer marginal de 39,0 % pour l'AMTI et de 15,7 % pour l'APC, de plus que le prix du saumon de l'Atlantique issu de l’élevage classique. Les résultats de l'analyse des classes latentes ont montré que les consommateurs qui affichaient une préférence marquée pour le saumon sauvage avaient des valeurs marginales élevées pour le saumon issu de l'AMTI ou de l'APC, mais qu'il était peu probable que le consommateur moyen de ce groupe en achète. Dans l'ensemble, les répondants ont indiqué préférer le saumon issu de l'AMTI ou de l'APC (44,3 % et 16,3 % respectivement) au saumon issu de l’élevage classique. De plus, s'ils avaient à choisir entre le saumon issu de l'AMTI ou de l'APC, ils choisiraient le saumon issu de l'AMTI.     

Broad‐based Agricultural Development versus Food Self‐sufficiency: A General Equilibrium Analysis in India

Intersectoral linkages are analysed using a CGE model based on a SAM constructed from Indian national accounts data for 1988–89. The model includes the rural non‐farm sector, public sector production and aspects of public policy. Evidence supports the arguments of Chakravarty (1987) and Ahluwalia (1986) regarding the importance of broad‐based agricultural development as opposed to increased production in the food sector alone aimed at achieving food self‐sufficiency.     

Spatial determinants of productivity growth on agri‐food Spanish firms: a comparison between cooperatives and investor‐owned firms

This study analyses the effect of the spatial factor, location, and interaction effects among peer companies, on the productivity growth of agri‐food companies in Spain. With this aim, we build a productivity growth index and apply a multiequational Seemingly Unrelated Regression on a sample of 344 Spanish cooperatives and investor‐owned firms for the period 2010–2012. Our findings show that agri‐food firms are influenced by spatial factors finding interesting differences between cooperatives and investor‐owned firms. With regard to the geographical location, cooperatives in the western of Spain show higher productivity growth rates, whereas investor‐owned firms in the northeast of Spain present better results. The interaction effect among closer peer companies is also a relevant factor to determine the productivity growth in agri‐food companies. This factor is more relevant for cooperatives than for investor‐owned firms.     

我国"数字渔业"建设探讨

本文简述了"数字渔业"的概念和在我国建设"数字渔业"的重要意义,介绍了支撑"数字渔业"的"3S"技术及其在我国渔业信息化中的应用情况,概括分析了建立"数字渔业"的主要内容,并就建设"数字渔业"策略问题提出了具体思路和建议.指出建设我国"数字渔业"要全面规划,统一标准,分步实施,逐步推进,不断完善;重点是渔业信息基础数据库系统和渔业应用系统的建设与开发.     

The Spanish path of agrarian change, 1950–2005: From authoritarian to export‐oriented productivism

The aim of this study is to determine whether the evolution of Spain's agrarian change, between 1950 and 2005, exhibits any features important enough to differentiate it from the common model of developed countries in Western Europe. On the one hand, the Spanish agrarian transformations share the main features of the changes in Western Europe: technological innovation, increased production and productivity, the diminishing importance of the agricultural sector, close integration with the industrial sector, and a high environmental impact. On the other hand, a series of important peculiarities can be observed in Spain's agrarian change: strong expansion of intensive livestock farming; the role of increased irrigation in explaining the transformation of agriculture; policies that offered very little support to the agricultural sector under a dictatorship that denied a voice to farmers; and the prominent role of agriculture in the economy despite its small contribution to GDP.     

山东省渔业人才队伍建设的思考

本文在肯定山东省渔业人才队伍建设取得成绩的基础上,根据渔业人才队伍层次偏低、结构和分布不合理等问题,提出了加强全省渔业系统人才队伍建设的具体措施.     

从美国加拿大财政支渔政策演变历程看渔业补贴之存在性

本文在回顾美国、加拿大渔业补贴演变历程的基础上,从渔业补贴对经济增长、国际贸易、可持续发展政策效应的视角评析了渔业补贴政策存在的合理性,并对我国渔业补贴政策调整提出有效建议.     

Long‐term versus temporary certified emission reductions in forest carbon sequestration programs*

Under the Clean Development Mechanism (CDM) of the Kyoto Protocol, forest projects can receive returns for carbon sequestration via two crediting instruments: temporary or long‐term certified emission reductions (tCERs or lCERs). This study shows the effect of lCERs on the private owner’s forest rotation intervals decision and carbon credit generation in afforestation and reforestation projects. A credit verification mechanism with a harvest penalty implemented under the lCERs policy distorts the timber harvesting decision and the corresponding carbon credit supply. Two opposing incentives are created by the lCERs mechanism which leads to either longer or shorter rotations compared to the Faustmann rotation, depending on which incentive prevails. Our numerical results show that both lCERs and tCERs seem to have similar impacts on harvesting incentives, but the resulting carbon supply differs among the instruments owing to the credit verification mechanism. The tCERs carbon supply curve is monotonically increasing in the carbon price, while a lCERs carbon supply is non‐monotonic and may have a backward bending region over a range of carbon prices.     

Restricted versus Unrestricted Choice in Labeled Choice Experiments: Exploring the Trade‐Offs of Expanding Choice Dimensions

A key methodological question in choice experiments is to identify whether there is a difference in choice behavior, and subsequent value estimates, when choices are constrained to mutually exclusive alternatives in labeled experiments compared to when combinations of alternatives are available. This issue is important when policy management options are represented in labeled experiments, as it is easier to represent management options as mutually exclusive choice alternatives, but combinations of management options may be more relevant in the policy world. This issue is tested with a case study application to the Great Barrier Reef in Australia. A split‐sample experiment is implemented where one survey includes four labeled alternatives: a status quo option and three specific policy management options (restricted choice). The other survey provides respondents with an unrestricted choice set by including a fifth alternative choice, labeled as “a combination of management options.” The results provide some evidence that adding a combination policy alternative does change the way that respondents view trade‐offs, but that choice behavior and subsequent value estimates are consistent across the two survey formats. Une question d’ordre méthodologique importante se pose dans le cas de la méthode des choix discrets expérimentaux : déterminer s’il existe ou non une différence dans les choix des répondants et dans les estimations subséquentes lorsque les alternatives proposées sont mutuellement exclusives et lorsque les alternatives proposées peuvent être des combinaisons d’alternatives mutuellement exclusives. Il s’agit d’un point important lorsque les options de gestion de politiques figurent dans des expériences avec des alternatives nongénériques étant donné qu’il est plus facile de présenter les stratégies de gestion comme des alternatives mutuellement exclusives, bien que les combinaisons de stratégies de gestion puissent être plus pertinentes pour les décideurs. Nous avons vérifié ce point à l’aide d’une étude de cas appliquée à la grande barrière de corail (Great Barrier Reef) de l’Australie. Nous avons utilisé la technique de l’échantillon fractionné : un premier sondage comprenait quatre choix distincts : conservation du statu quo et trois alternatives de gestion de politiques (choix contraint); un deuxième sondage comprenait un choix complet d’alternatives incluant une cinquième alternative intitulée « combinaison de stratégies de gestion ». Les résultats semblent indiquer que l’ajout d’une telle alternative influence la perception des répondants à l’égard de la valorisation des attributs, mais que les choix des répondants et les estimations subséquentes se ressemblent dans les deux formules de sondage.     

浅论明代的渔业税制

本文探讨了明代渔业的征课水域与征收方式，并叙述其渔课种类与渔税名目，揭示其渔税征解过程及渔税支配方式，最后论述了明代的渔业税制改革并分析其所取得的实际效果。较为全面地论述了明代渔业税制的各个方面。     

陕西渔业生态环境可持续发展探讨

2004年,笔者对陕西重要渔业水域生态环境质量状况进行了监测与调研.从总体看,陕西渔业水域质量良好,但也存在渔业水域污染问题.为此,作者分析了陕西渔业水域生态环境质量状况及污染的主要因素,在此基础上提出了陕西渔业水域生态环境与可持续发展的对策和建议.