Improving fleet efficiency to maximise economic yield in a Western Australian prawn fishery

The Shark Bay trawl fishery is Western Australia's most valuable prawn fishery (worth AUD$25 million in 2014). The 18-vessel fleet targets western king prawns (Penaeus latisulcatus), brown tiger prawns (P. esculentus) and also retains saucer scallops (Ylistrum balloti) and blue swimmer crabs (Portunus armatus). Increased fuel prices, falling prawn prices and lower catches of other species, following extreme environmental events, have impacted fishery profits. A biomass dynamics model with an economic component indicated that total revenue levels start to decline when annual effort increases beyond ~ 200 fishing days per boat. Annual effort required to achieve MEY, when based solely on prawn fishing, is 115–150 days per boat after accounting for fixed and variable fishing costs and annual fishing efficiency increases of 1–2%. From 2007–2014, the adjusted effort was 188–192 days per boat. Fishing occurred between March and November during 7–8 fishing periods, separated by 5–8 day (low catchability) moon closure periods. An empirical daily profit assessment (2007–2015), accounting for recruitment variation, daily prawn size compositions, monthly market prices for different prawn species and sizes, and daily fishing costs, showed vessels made profits on ~ 115–160 days and losses on ~ 15–55 days per year, when fishing occurred near the full moon. The fishery benefitted in 2013–2015 by starting later in the year and better targeting within-season effort. This management strategy within the effort-control framework, which improved profitability, maintained higher spawning stocks and reduced ecosystem fishing impacts, has wider application in prawn fishery management.     

虚拟水战略新论的社会经济效益分析——以石羊河流域民勤县为例

虚拟水战略已经被认为是一种提高全球水资源利用效率和缺水地区获得水安全的有效工具. 虚拟水战略新论指出, 应充分利用各种社会资源, 打通优化配置水资源(实体水和虚拟水)的渠道. 虚拟水战略能否有效实施的首要任务, 是地区产业结构内部配置的优化. 本文在估算民勤县主要农作物虚拟水量的基础上, 利用部门水效益分析了虚拟水由农业(种植业)部门向第二、三产业转移的三种情景下产生的净效益和创造的社会就业机会, 刻画了实施虚拟水战略的重要理论意义, 佐证了虚拟水战略全新定义的现实意义.     

气象服务在江苏农业减灾增效中的效用分析

气象为农业服务是气象服务的重要方面,科学定量评估农业气象服务效益是气象在农业减灾增效中更好发挥作用的有效手段。本文以江苏省为例,选取大农业范畴的种植业、蔬菜、茶桑果、林业、牧业、渔业、农林牧渔服务业为研究对象,通过问卷制作和调查,了解不同领域的农业用户群和专家对气象服务的满意度评价。结果表明:2005—2009年的满意度逐年上升,其中2009年满意度高达92.90%;通过改进后的德尔菲评估法,计算发现此5 a的气象服务在江苏农业减灾增效中的效用越来越显著,经济效益也在逐年上升,总效益约为551.32亿元。由此可见,气象服务工作不仅得到了广大农业用户群以及专家的肯定,而且在农业中产生的经济效益也是非常显著。此外,文中还对气象服务经济效益的定量评估方法进行了有益的探讨。     

The Spatio-temporal Pattern of Regional Land Use Change and Eco-environmental Responses in Jiangsu,China

Land use change and its eco-environmental responses are foci in geographical research. As a region with uneven economic development, land use change and eco-environmental responses across Jiangsu Province are relevant to China’s overall development pattern. The external function of regional land use changes during different stages of economic development. In this study, we proposed a novel classification system based on the dominant function of land use according to “production-ecology-life”, and then analyzed land use change and regional eco-environmental responses from a functional perspective of regional development. The results showed that from 1985 to 2008, land use change features in Jiangsu were that productive land area decreased and ecological and living land areas increased. Land use changes in southern Jiangsu were the most dramatic. In southern and central parts of Jiangsu the agricultural production function weakened and urban life service function strengthened; in northern Jiangsu, the mining production function’s comparative advantage highlighted that the rural life service function was weakening. Ecological environmental quality decreased slightly in Jiangsu and its three regions. The maximum contribution rate to ecological environmental change occurred in southern Jiangsu and the minimum rate was located in the north. Eco-environmental quality deteriorated in southern and central Jiangsu, related to expanding construction land in urban and rural areas. Ecological environmental quality deterioration in northern Jiangsu is probably due to land development and consolidation. The main reason for improvements in regional ecological environments is that agricultural production land was converted to water ecological land across Jiangsu.     

Approaches for Monitoring and Assessment of Ecological Benefits of National Key Ecological Projects

In recent decades, due to the combined effect of human activities and climate change, the ecosystem of our country has been continuously degraded, seriously affecting the sustainable economic and social development. In order to protect and recover the ecosystem, China has invested heavily in launching a series of key ecological programs and projects including North Shelter Forest Program, Grain for Green Project and integrated ecosystem management of rock desertification. How to comprehensively and timely grasp the ecological effects and existing flaws of the implementation of key ecological projects so as to scroll the implementation of ecological projects and ensure the implementation effect of the projects, and promote the follow-up ecological engineering deployment of being scientific and space-oriented is a major imperative for the country. Therefore, the National Key Research and Development Program of China set up the project of “Monitoring and Assessment of Ecological Benefits of Key Ecological Engineering in China”. Through the implementation of this project, we will establish an indicator system for monitoring and evaluating the ecological benefits of key ecological projects, developing various technical systems for monitoring and evaluating the ecological benefits of key ecological projects, quantitatively evaluating the ecological benefits of key ecological projects, and concise the technical approaches to enhancing ecological benefits. We will provide a scientific basis for future planning and management of key ecological projects.     

黄河下游防洪工程体系减灾效益计算模型研究

以黄河下游防洪工程体系为背景,系统研究了防洪工程体系减灾效益计算有关水文、水力学、工程、经济等方面的问题,提出了防洪工程体系减灾效益计算的整体思想,开发了相应的计算模型。研究中还开发了用于分析黄河下游防洪保护区12万km2范围决堤洪水成灾状况的二维非恒定流模型。结合黄河下游防洪保护区具体情况,提出了财产状况、洪灾损失率、地形地物数据等减灾效益计算的重要参数。实例计算结果表明:模型计算结果合理,对解决防洪工程体系减灾效益计算问题是非常有效的。     

新疆棉花比较优势的进一步分析:基于经济收益

经统计分析 ,棉花净产值与玉米净产值之比X3对年度皮棉增加率Y2有极显著影响 (p <0 .0 1)、棉花净产值与 (玉米 +小麦 )平均净产值之比X4、棉花减税纯收益与玉米减税纯收益之比X6、棉花减税纯收益与 (玉米+小麦 )平均减税纯收益之比X7对年度皮棉增加率Y2有显著影响 (p <0 .0 5 )。新疆中绒棉的X3介于山东和安徽之间 ,X4处于较高水平 ,X6比山东、安徽分别高 0 .8和 0 .3或 73%和 19%,X7比山东、安徽分别高 1.1和 0 .2或 92 %和 10 %,可见新疆中绒棉的种植优势是存在的。新疆长绒棉的优势更大 ,以上 4个指标比山东、安徽二省均值高 2 6 %～ 10 0 %。这些指标的增加 ,对年度皮棉增加率的贡献是明显的。按回归分析 ,X3、X4、X6、X7每增加 1,分别意味着当地皮棉比上年度有增加 33.9%、36 .8%、16 .8%、12 .7%的趋势。     

龙羊峡水库兼顾中下游供水运用初步研究

借助于“黄河流域水资源模拟模型“,采用长系列模拟方法计算了龙羊峡水库兼顾中下游供水的效益。初步研究表明,龙羊峡水库可以在一定程度上兼顾中下游用水,特别是在枯水年能够有效减少干流缺水,虽然这是以上游梯级发电效益减少为代价,但代价甚微。     

纯井灌区灌溉效率分析

通过对小麦和玉米生长期间的有效降雨量及灌溉水量、灌溉利用系数、灌溉水量及作物产量的关系分析计算 ,阐明了有效降雨量 ,充分利用有效降雨量合理进行灌溉 ,提高灌溉效益的方法。     

论三峡库区地质灾害防治工程综合效益

从防治地质灾害的角度，探讨防治工程如何结合三峡库区经济、社会、人口、资源、环境全面协调发展，力求近期与远期的目标利益为最佳兼顾，从单纯的地质灾害工程防治综合向解决社会经济和环境保护问题转变，坚持防治效益与生态效益、经济效益和社会效益并重，将治理保护与开发利用相结合，力求获得库区整体的最大综合实效。