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Frid C. L. J; Harwood K. G.; Hall S. J.; Hall J. A. 《ICES Journal of Marine Science》2000,57(5):1303-1309
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New Zealand seamounts support major fisheries for several deepwater fish species, including orange roughy (Hoplostethus atlanticus) and smooth oreo (Pseudocyttus maculatus). Although a high proportion of features in the depth range 500–1000 m have been fished, very little is known about the ecological impacts of bottom trawling on seamounts. The potential impact is likely to be influenced by the spatial extent and frequency of fishing. A new index is presented to assess the relative intensity of trawling on New Zealand seamounts. The fishing effects index (FEI) incorporates information on the density of fishing on the seamount as a proportion of the seabed area and also on tow direction. Detailed fisheries data from more than 250 000 tows were examined to calculate FEI for New Zealand seamounts. The most intensively fished seamounts were on the south Chatham Rise, an area characterised by a large number of relatively small features which were fished serially for orange roughy in the 1980s and 1990s. Other seamounts with high FEI were on the north Chatham Rise, Challenger Plateau, and off the east coast of the North Island. A range of sensitivity analyses indicated that the general rankings of seamounts were relatively robust to the choice of arbitrary thresholds used to assign tows to seamounts. 相似文献
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黄渤海区捕捞结构的研究 总被引：4，自引：0，他引：4
根据2010年对黄渤海沿海32个主要渔港、渔村和5家网具生产厂家的实地调查和现场测量资料,结合2009年度三省一市(河北、辽宁、山东、天津)的渔具渔法调查报告以及1983~2009年中国渔业年鉴中记载的捕捞产量分类统计资料,对黄渤海区捕捞结构进行了研究.研究结果表明,黄渤海区主要捕捞品种有30种之多,其中年渔获量超过万吨的有14种鱼类、5种甲壳类、4种头足类、2种海蜇和6种贝类.渔业资源品种的多样性决定了黄渤海区捕捞结构的多样化和多层次的特点,现有9大类19型23式130种网型或作业方式,同时受渔业资源变动的影响,捕捞网具也在变化,不断有旧的渔具消失和新的网具出现.其中,拖网是主要作业方式,贡献率为38.47%~51.79%,且近几年还有上升的趋势;其次为刺网,贡献率从1983年最低时的7.66%逐步上升到目前的30.14%;第三为张网,贡献率从1985年最高时的34.31%下降到目前的10.49%;围网和钓具的贡献率一直较低,均不足4%,其他渔具的贡献率为5.98%~13.30%.目前黄渤海区渔业结构的调整方向应当是减少拖网作业,控制刺网总量,限制张网、陷阱类渔具和地笼,鼓励发展钓渔业 相似文献
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Despite its legal prohibition since 1998, the nylon monofilament net is still widely used in Senegalese artisanal fisheries. To achieve a complete ban on monofilament use, it is necessary to understand the main arguments for its continued use and what alternatives exist. Using a field experiment among local fishers as well as empirical knowledge and a literature review, this article highlights the challenges to the eradication of nylon monofilament. Our study shows that in a context where decision-makers pay too much attention to social, economic and political stakes, the efficiency of nylon monofilament nets confers a major advantage upon which fishers rely, and this counters any regulatory action against this type of gear. Moreover, numerous studies globally have indicated that communication campaigns that focus on the ghost-fishing power of this type of net seem to be inappropriate. We concluded that the issue of continued use of monofilament should be addressed through an integrated fisheries management programme that reduces overcapacity and fosters sustainable fishing practices. 相似文献
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Definitions of overfishing from an ecosystem perspective 总被引：8，自引：11，他引：8
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《Marine Policy》2016
Iceland׳s fishing industry has outperformed fishing industries in neighboring countries in recent years. This paper identifies key factors in market structure in recent decades that contribute to long run profitability of the Icelandic fishing (and fish processing) industry using semi-structured interviews with industry participants, and compares those with similar results from Norway. Further, the development of profitability in the Icelandic and Norwegian demersal fishing industries is used to assess the long run effects of different management systems on quality, product focus and profitability. The results indicate that three key changes in Icelandic regulation during the 1980s were important to the development of long run profitability within the fishing industry: the abolition of export barriers, the introduction of an individual transferable quota (ITQ) system and the establishment of fish auctions. A large and growing literature supports the role of ITQs in ensuring long run profitability. The importance of market structure for profitability has only recently been identified, affecting the ability of value chains to become market oriented and supply homogenous product flow from heterogeneous raw material. Comparison with Norway indicates that while individual transferable quota management does improve profitability in fishing to a certain extent, management systems must facilitate a strong market connection from consumers, through the stages of retail and processing, to fishers for the full realization of profit potential in the fishing industry. 相似文献
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两种结构延绳钓渔具使用效果的比较研究--以金枪鱼(Thunnus)为例 总被引：3，自引：1，他引：2
分析比较两种不同结构的延绳钓渔具 1998年 2～ 9月期间在印度洋东部作业的生产效果。结果显示 ,钓具 A(平均放钓水深 90 .8m)与钓具 B(平均放钓水深 72 .7m)相比 ,钓捕效果差异显著 ,在渔获尾数、渔获重量、上钓率三个指标上 ,A钓具分别高于后者 2 9.52 %、30 .2 1%和9.80 %。提出了符合印度洋生产需要的钓具优化设计方案。 相似文献
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海洋捕捞产业是浙江省舟山市的传统基础支柱产业，但由于中日和中韩渔业协定的签订和生效，成千上万的渔民面临着转产转业问题。本文通过几年来的实践分析，提出了四点建议和措施，为舟山市的渔业可持续健康发展提供建设性意见。 相似文献
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通过对玻璃钢渔船的五种船体骨架结构形式的弯曲试验,测得其力学性能。并且运用加权因素法对试验结果进行优化。研究结果表明按断面形状,梯形优于矩形;按断面结构,木质芯材优于泡沫芯材,泡沫芯材优于空心结构。 相似文献
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水流作用下渔网养殖空间变化的计算方法 总被引：1，自引：0，他引：1
渔网的动力分析是养殖网箱设计和优化的基础。通过把一系列杆相互铰接在一起,建立网的模型,模拟网在来流作用下的变形。作用在杆上的水动力可以通过Morison公式来计算,采用有限单元的离散方法,并利用网目合并的方法来减少总的自由度数目。模型的计算结果同试验成果做了对比,计算与试验在柔性网的变形方面,结果吻合良好。 相似文献
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Carlos A. Perez-Labajos 《Marine Policy》2012,36(3):630-635
In the period 1983-2007, The European Union controlled the evolution of the capacity of its fishing fleet through the so-called Multi-Annual Guidance Programmes (MAGPs). As a result, The European Union reduced the number of fishermen, fishing vessels, gross tonnage and power. However, the end of this period saw an increase in the average size of the fishing vessel and a reduction in crew size. The new “average fishing-vessel” was a more technologically advanced vessel with a greater fishing capacity and a higher degree of autonomy. The aim of the study presented here is to determine the degree of inequality to be found between the fishing capacities of the fleets of the European Union, and to verify whether the evolution of the “average fishing-vessel” responds to a homogenous trend shared by all of the fishing fleets of the European Union or whether it is in fact more unequal. The study formalises a methodology, using Theil indices, which enables the inequalities found between the capacities of the fishing fleets during the period of application of the MAGP adjustment polices to be analysed. The study uses data on fishermen, boats and tonnages from 13 countries of the European Union and results are obtained for the inequality indices of the average size of the fishing vessels, their degree of technological advance and their average crews. 相似文献
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High sea industrial longline fishing can be understood as a case study of the cultural, economic, environmental and social impacts of unsustainable fishing technology. While much attention has been attributed to the impact of industrial longlines on the marine ecosystem, little is known about the impact of longline fishing on local food security, employment, cultural belief systems and traditions, revenue generation from marine tourism and climate change. New data demonstrate that the contributions of Marine Protected Areas, marine tourism and recreational fishing to local coastal economies dwarf the contributions of longline fishing. When combined with the impact of overfishing on coastal fishing communities and fish consumers, policies promoting sustainable fisheries must be expanded to take these other factors into account along with issues of biodiversity. 相似文献