Sustainability of fish pond culture in rural farming systems of Central and Western Cameroon

In Sub-Saharan Africa, fish ponds are often an integral part of farming systems but have suffered from a lack of viability and sustainability. The present study aims to understand the strategies used by fish farmers to overcome economic and environmental constraints. In 2008 and 2009, fish farmers were surveyed in Central and Western Cameroon, and the fish production systems were classified by cluster analysis. Four broad types were identified according to the complexity of household operations. The development of extensive systems (large-scale and low-input) in rural areas of central Cameroon is induced mainly by abundant available land. For semi-intensive systems in both regions (small-scale and high-input in the Western Region, large-scale and high-input in peri-urban areas of the Central Region), horizontal integration is not sufficient to make fish production profitable and sustainable. More intensive fish farms tend towards vertical integration, in which farmers establish close links with input suppliers. Main causes of low productivity of semi-intensive systems (1–2?t/ha/yr) are both lack of knowledge of fish farming principles by farmers and lack of technical improvement by extension agents and researchers which need to consider the local complexity of farming systems to develop and intensify fish production. The adaptation of development strategies to socio-economic and environmental contexts is a necessity to hope for an increase in fish pond aquaculture production in Africa.     

利用湿地废水资源化的效益分析——以八湖镇荷塘湿地为例

根据我国对湿地废水资源化利用的现状,阐述利用人工湿地净化污水的理论基础。以临沂市八湖镇荷塘湿地为例,对荷塘湿地净化蔬菜加工废水进行经济效益、社会效益和环境效益分析。结果表明,应用荷塘湿地净化蔬菜加工废水技术可有效缓解水资源危机,维持生态平衡,进而实现经济、社会和生态环境的协调及可持续发展,其产生的效益较大,可为我国类似地区开展蔬菜加工废水资源化利用提供借鉴。     

舟山市对虾养殖业可持续发展的问题及对策

近几年来，舟山市的对虾养殖业发展迅速，为舟山市的粮食安全、食物供给、经济增长、就业做出了很大贡献。然而，对虾养殖所产生的环境、社会和经济问题也不断暴露，对虾养殖业的可持续发展问题面临巨大挑战。论文首先阐述了水产养殖业可持续发展的理论由来，接着分析了舟山市对虾养殖业目前的发展状况，最后针对舟山市对虾养殖业中出现的各种问题，提出了相应的政策建议，为舟山市对虾养殖确定科学的发展方向提供了一定参考。     

水池裂缝防治

介绍了该企业在河南中平能化集团供水总厂四分厂水池裂缝防治方面的一些做法,具有较好的推广价值。     

Neoliberal Wave Rocks Chilika Lake, India: Conflict over Intensive Aquaculture from a Class Perspective

Since the beginning of the 1990s, Chilika Lake, situated on the coast of the Indian state of Orissa, has been the scene of a conflict over intensive aquaculture practices, culminating in a process of de facto privatization of the lake. This conflict can be divided into two distinct phases that have seen the involvement from village to state level of different actors: in particular the traditional fishing people and the dominant classes in Orissa. This article analyzes the socio-economic dynamics governing the conflict. The specific aim is to investigate the dynamics of class reproduction, new forms of class oppression and the emergence of new forms of class consciousness related to the transformations caused by the new aquaculture practices. The role of class in India today is discussed and related to a fieldwork-based analysis of the two phases of this movement against intensive aquaculture.     

高滩位区花蛤反季节高效池塘生态养殖模式经济效益分析

2007～2009年，在莆田市后海垦区高滩位区采用复合池塘生态系统生态调控养殖技术开展了花蛤反季节高效池塘生态养殖。2007。2008年，13．33hm2示范塘收获花蛤平均规格为59粒／500g，销售平均价格为4．93元／500g，单位产量为5415．75kg／hm2，养殖净利润较传统养殖模式（按照净利润18000元／hm2）的养殖净利润提高了26．80％，投入产出比和净投入产出比分别为1：1．67和1：0．75。2008．2009年，13．33hm2示范塘和33．33hm2推广塘生产的花蛤单位产量分别为6042．49kg／hm2和5850．75kg／hm2，收获规格分别为50粒／500g和54粒／500g，平均价格为4．8元／500g，较福建省花蛤集中大量上市时的价格3．2元／500g有大幅度提高，示范和推广池塘的养殖净利润较传统养殖模式的养殖净利润（按照净利润18000元／hm2）分别提高了58．31％和44．82％，投入产出比分别为1：1．97和1：1．87，净投入产出比分别为1：0．97和1：0．87。结果表明：采用花蛤反季节高效池塘生态养殖模式可以大幅度提高高滩位区花蛤池塘养殖的经济效益。     

我国水产养殖业环境污染防治研究

随着渔业的发展,水产养殖业已经成为我国粮食安全保障以及实施"紧缺资源替代"战略的重要组成部分,但是水产养殖业环境污染也越来越受到关注,保护渔业资源和环境成为实现水产养殖业可持续发展的关键因素。本文从水产养殖业环境污染防治的战略角度出发,结合我国水产养殖业污染的现状,分析了水产养殖污染产生的各种机理,提出水产养殖业环境污染防治的战略性政策建议。     

流沙湾海域水产养殖结构与布局调查分析

本文对流沙湾水产养殖结构与布局进行了调查分析。结果表明,流沙湾水域养殖面积过大,占总面积的19.7%;养殖品种单一,贝类养殖面积占水域养殖面积的91.9%;贝类主要采用长桩式吊养模式,局部养殖密度大,导致海区流速减缓,水流不畅,养殖自身污染严重。近年来,流沙湾贝类养殖产量为22238吨,珍珠产量为18.5吨,占全国海水珍珠总产量的50%以上。分析认为应降低海湾养殖密度,调整养殖结构,合理规划养殖布局,实施海域有偿使用和养殖许可证制度,从而确保流沙湾水域生物资源可持续利用。     

撬动罗非鱼国内销售市场的几点思考

罗非鱼是联合国粮农组织特别推荐养殖的优良鱼种,罗非鱼自身的特点决定了罗非鱼非常适合大规模人工养殖。我国已经成为最大的罗非鱼养殖国家。由于市场因素、国际金融危机等因素,使我国罗非鱼养殖产业出现了增产不增收的恶性循环现象。本文通过分析罗非鱼养殖和加工现状、罗非鱼系列产品开发、罗非鱼废弃物综合利用、政府制定优惠政策、培育规范的罗非鱼国内销售市场等,提出了切实可行的促进我国罗非鱼产业快速发展的途径,为我国罗非鱼产业的快速发展提供了参考。