Aquaculture stakeholders role in fisheries co-management     

《Marine Policy》2017

Industrial aquaculture has become one of the main protagonists both on the coasts and in international policy aimed at regulating matters concerning the sea. This new role is reflected in the recently adopted Common Fisheries Policy of the European Union, where the need to promote the sector and the involvement with other local actors, specifically artisanal fishers, is highlighted. However, the official promotion of this activity could be overvaluing its benefits while, at the same time, undervaluing the new barriers that it is introducing in fisheries co-management. Centered in Valencian Community (Spain) and through a qualitative methodology, this paper examines the views and positions of stakeholders directly involved in aquaculture activity (biologists, aquaculture businessmen and policy managers) on the possibilities of joint participation. It is concluded, that eroding the detected mistrust among stakeholders through "hybrid forms of participation" would be a necessary prerequisite to setting up a common framework for involvement leading to an effective co-management.  相似文献   

FAO's statistic data and sustainability of fisheries and aquaculture: Comments on Pauly and Zeller (2017)     

《Marine Policy》2017

In a recent commentary, Pauly and Zeller disagreed with the Food and Agriculture Organization's interpretation of its global capture fishery production records, arguing that trends were distorted by unreliable statistics in some countries. They criticized FAO for not having used their “catch reconstructions” in the 2016 State of the World Fisheries and Aquaculture (SOFIA) report and questioned the interpretation and significance of FAO's aquaculture production statistics. In this paper, we refute their claims and demonstrate that their critique is based on fundamental misunderstandings caused by mixing up statistical metrics and using simple normative explanations to interpret highly complex datasets. We explain how FAO maintains, curates and updates the only validated source of global fisheries landings, describe our capacity building projects and activities underpinning the annual updates for the over 231 different sources of fisheries data, and clarify such updates include dialogues with member countries to improve and revise present and historical records. FAO will continue to work closely with member states, IGOs, NGOs, academia and civil society, to further improve fishery and aquaculture databases, while calling on states to make renewed efforts to improve data quality. It also welcomes research efforts that contribute to the improvement of statistical data which are critical to the sustainable management of fisheries and aquaculture.  相似文献   

深切河谷斜坡地带岩溶地下水的赋存特征及开发利用——以石阡县安家寨地下水系统为例          下载免费PDF全文

胡仁发  王明章  肖腾 《贵州地质》2017,34(2):116-122

本文以石阡县安家寨片区开放型岩溶地下水系统为研究对象,以石阡县安家寨地区的实际勘查成果为基础,指出了在该类型地区受地质构造控制,可能存在局部封闭型的阻水型蓄水构造,成为该类型地区寻找和开发利用地下水的有利地带。并在此提出在深切河谷斜坡地带寻找有开发价值的地下水源地的方向为:在"开放型"水文地质系统中寻找局部的"封闭型的地下水蓄水构造",可作为该类型地区勘查和开发岩溶地下水的借鉴。  相似文献   

萨拉乌苏河流域MGS2层段主要氧化物变化及其指示的气候波动   总被引：4，自引：2，他引：2  

李后信  李保生  温小浩  欧先交  李志文  牛东风  杜恕环 《中国沙漠》2010,30(4):808-815

萨拉乌苏河流域与MIS2相同时代的MGS2地层段记录了5.5个由风成砂与河流相或湖沼相构成的沉积旋回,通过对各沉积旋回的主要氧化物分析表明：河湖相中Al2O3、TOFE、K2O、MgO、CaO、Na2O、TiO含量通常明显高于风成砂,而SiO2含量则呈现相反的变化,构成了与沉积旋回相对应的5.5个主要氧化物变化旋回。结合各主要氧化物的化学迁移特性和剖面所在区域的地貌特征进行分析,认为该剖面的主要氧化物变化旋回是气候波动的反映,一个主要氧化物含量变动旋回指示了一个干冷-暖湿旋回,也即一个冬夏季风先后演替的气候旋回。MGS2持续的时间仅为12 ka,一个冬夏季风环境的变化大致平均仅需要2 ka,一个冬季风或者夏季风环境的平均持续时间大约1 ka。显然,这是一个千年尺度的环境变化。研究还表明,MGS2气候波动与晚冰期气候变化以及相关的Heinrich事件具有良好的对应关系。可以推断,MGS2记录的千年尺度环境变化是全球环境变化在本区域的反映。  相似文献   

哀牢山——元江河谷对区域地理分异的影响   总被引：1，自引：1，他引：0  

冯彦  李运刚 《地理学报》2010,65(5):595-604

基于对哀牢山是云南东西部自然界线的认识,对比分析哀牢山-元江河谷东西两侧5个纬度带、近几十年的重要自然要素、农业种植结构、农民收入来源及区域经济发展水平特征,结果表明:西部较东部地形高差较大、≤15°宜农土地比重较少、水汽和热量资源更丰富,形成东西部间显著自然环境差异;东部较西部的经济作物、旱作种植比重更高,表明东西部在农业生产结构方面存在明显分异,而各部的种植结构(以旱作种植比例为例)在各纬度间呈近纬向的相似性变化;东部较西部的人均农业产值、农民纯收入及人均GDP更高,表明东西部经济发展水平存在较大时空差异,而东西各部内则存在较好的相似性。从区域社会经济发展方面佐证了哀牢山作为云南东西部界线的存在。  相似文献   

基于ALOS遥感数据的新丰江流域生态安全GIS评价     

孙彩歌  钟凯文  刘旭拢  解靓 《地球信息科学学报》2010,12(2):301-308

基于ALOS遥感影像,采用10m×10m的栅格精度,以乡镇行政区划作为综合评价单元,在G IS的支持下,获取了18种评价因子信息。通过建立生态安全指数模型,计算出每个栅格和每个乡镇区域的生态安全指数并将其划分为6个等级,即Ⅰ级到Ⅵ级(生态安全状况由非常安全到极不安全)。结果表明,新丰江流域内的生态安全状况整体上较好,但安全等级分布不平衡,具有明显的区域性特征,生态堪忧地区为居民及工矿用地密集区,主要分布在流域的北部、东南部和中部的采矿区,如上坪镇、元善镇和上莞镇等;生态较为安全的区域主要分布在流域中部,如新丰江库区附近的锡场镇、半江镇等。该方法为流域的生态安全评价、预警、保护及管理提供了有效手段,具有积极的实用价值。  相似文献   

Biosorption of Methylene Blue from Aqueous Solution Using a Bioenergy Forest Waste: Xanthoceras sorbifolia Seed Coat     

Zengyu Yao  Lihua Wang  Jianhua Qi 《洁净——土壤、空气、水》2009,37(8):642-648

Xanthoceras sorbifolia seed coat (XSSC), a bioenergy forest waste, was used for the adsorption of methylene blue (MB) from aqueous solutions. The effects of adsorbent dosage, pH, adsorbate concentration and contact time on MB biosorption were studied. The equilibrium adsorption data was analyzed by Langmuir and Freundlich isotherm models. The results indicated that the Langmuir model provided the best correlation with the experimental data. The adsorption capacity of XSSC for MB was determined with the Langmuir model and was found to be 178.6 mg/g at 298 K. The adsorption kinetic data was modeled using the pseudo‐first order, pseudo‐second order, and intraparticle diffusion kinetic equations. It was seen that the pseudo‐second order equation could describe the adsorption kinetics, and intraparticle diffusion was not the sole rate controlling factor. Thermodynamic parameters were also evaluated. Standard Gibbs free energy was spontaneous for all interactions, and the biosorption process exhibited exothermic standard enthalpy values. The results indicated that XSSC is an attractive alternative for removing cationic dyes from wastewater.  相似文献   

Valley confinement as a factor of braided river pattern for the Platte River   总被引：2，自引：0，他引：2  

Lisa M. Fotherby   《Geomorphology》2009,103(4):562-576

The Platte River in Nebraska has evolved in the twentieth century from a predominantly braided river pattern to a mélange of meandering, wandering, anastomosed, island braided, and fully braided reaches. Identifying the factors that determine the occurrence of a fully braided main channel was the objective of this study. Aerial photography, gage flow data, ground-surveyed cross sections, bed material samples, and the results of sediment transport modeling were used to examine factors that control spatial change in main river pattern of the central Platte River. Valley confinement is identified as the determining factor of braided river in nine of eleven divisions of the central Platte River. Flow reduction and the interruption of sediment supply are identified as determining factors preventing fully braided river in the remaining two of eleven reaches.Valley confinement, the topography which limits the width of the floodplain, was initially measured as width between historical banks (predevelopment river banks). This metric was later refined to width between confining features (historical banks, remnant bars, bridge abutments, protected banks and levees). Under existing conditions, the main channel of the central Platte River is fully braided when valley confinement (width between confining features) is 600 m or less and begins to divide into the multiple channels of an anastomosed pattern when valley confinement (width between confining features) exceeds 600 m When Platte River flow is divided between two to four major anabranches, a fully braided pattern in the main channel of the main anabranch requires a more confined valley of 400 m or less.Valley confinement is demonstrated to be the dominant factor in determining river pattern in the central Platte River, although this factor is not normally considered in the continuum of channel pattern model. Conclusions from this study can be used to increase the occurrence of fully braided main channel in the central Platte River, to aid habitat recovery for endangered or threatened bird species that favor this river pattern. Consideration of valley confinement with river continuum factors can aid river managers by improving predictions of river pattern in response to management actions.  相似文献   

元谋干热河谷强侵蚀区土桥发育特征与演化过程     

舒成强  何政伟  张斌  蒋良群  罗明良  林叶彬 《热带地理》2014,34(3):344-350

元谋干热河谷区的土桥地貌是当地常见的一种潜蚀地貌,是区域地貌的重要组成部分。元谋土桥是造成当地水土流失的重要原因之一,研究其形态特征及演化过程对于认识区域地貌演化及生态地质环境的治理具有重要的现实意义。2009―2013年,通过多次对土桥形态特征、分布区域的地形地貌的现场测定,对土层进行了分析。结果表明：1）元谋土桥大部分分布于冲沟中上游的沟底,少部分分布于冲沟边缘的峭壁下,有连续出现,也有单独出现;2）土桥发育的土层具有层间差异性,即桥洞所在土层较其顶部土层抗崩解性弱,易受侵蚀;3）地层构造节理及冲沟坡度的变化等因素对土桥的形成具有一定的影响作用;4）元谋土桥的形态、结构与一般天生桥或人工桥梁具有相同的桥体结构,形态规模一般都不大;5）演化过程遵循一般事物的发展规律,分为萌芽期、年轻期、成熟期、消亡期４个阶段;6）元谋土桥与陷穴、冲沟等地貌具有一定的耦合关系。  相似文献   

长江流域稻田生态系统的水分和养分转换过程   总被引：4，自引：0，他引：4  

周卫军  王克林  王凯荣  谢小立  刘鑫  王勤学  渡边正孝 《地理学报》2004,59(1):25-32

田间模拟施肥进步和灌溉模式的定位试验在中国科学院桃源农业生态试验站进行。结果表明施肥制度和水分管理模式显著地影响水分和养分的转化过程和生产效益。单施N的产量效应为4.5 kg/kg,而NP或NPK配施养分总的产量效应分别为8.8 kg/kg和8.0 kg/kg;有机物料循环的增产率为56.8%,在有机物料循环的基础上配施NPK化肥最大的增产率可达到80.1%;化肥应用的进步可使水稻产量增长62.5%或通过施肥实现的水稻产量中由于化肥应用所占的贡献份额为38.4%,有机无机肥配合水稻产量增长80.1%,或通过施肥达到的产量中有机无机肥配合所占的份额为44.4%。本区双季稻年灌溉需水量为5838 m³/hm²,年变异C.V = 8.3%。晚稻灌溉占全年的71%,7~9月是灌溉需水高峰期,占全年灌溉量的68%。生产灌溉效率 (灌溉水量与产量之比)：生物量3.67 kg/m³,精谷量1.48 kg/m³。常规管理田间水分分配为：蒸散占1/2,翻耕整地占1/6,植物构成占1/21,田间渗漏占1/14,其它环境耗水 (维持) 占1/5。耕灌雨养管理翻耕整地和田间渗漏比例过高。不同灌溉处理试验表明：双季稻生产的灌溉,以早稻保持水层灌溉,晚稻按需配额灌溉的模式比较适宜。  相似文献