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本文根据对台湾北部渔场中上层鱼类为期三年的生产性探捕试验结果,着重分析了莆田市现有灯光围网作业渔船采用的渔具渔法在该渔场的适应情况和生产性探捕试验的经济效益。指出了该渔场中上层鱼类的渔期、中心渔场位置和渔获组成。 相似文献
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根据山东圣海渔业集团公司渔轮赴几内亚比绍海域生产过程中有关石斑鱼延绳钓渔具使用的试验情况,简述了渔场自然环境及目前应用的钓捕石斑鱼效果较好的延绳钓网具主要参数,重点探讨了渔具改进的主要措施。 相似文献
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<正> 海洋捕捞是一门综合性的应用技术科学。其范畴包括捕捞对象、渔场、渔具和渔法以及技术管理。广义而言,尚包括渔船、渔业机械和探鱼仪器,以及捕捞作业中进行渔具性能测试的有关仪器。然而,其核心应是研究渔具和渔法对捕捞对象习性行动和渔场环境条件变动的适应性问题。亦即以渔法 相似文献
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远洋大型中下层单拖网,是目前较为主要的渔具渔法之一,本文对我公司大型远洋单拖加工船“明昌轮”在生产作业中,渔具渔法,渔期渔场,网具在拖曳过程中有关注意事项及今后的设想与建议等问题,作了较为详细的阐述,供参考。一、渔具渔法（一）渔具1．网具规格：52目X25M网具 相似文献
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定置网是沿岸及内陆水域的重要渔具之一，在世界渔业中占有一定的比重。由于定置网是一种被动性的渔具，因此定置网的渔获，大都取决于渔场里洄游鱼群的行动与数量，特别是鱼群的洄游量．实验证明，只有当渔场里的鱼群洄游量超过一定数量时，定置网才开始有渔获。因此，在鱼群洄游量少的水域，是无望得到渔获的。由此表明鱼群洄游量少的水域，不能形成定置网渔场。 相似文献
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南海区拖网和张网渔具对渔业资源的影响 总被引：1，自引：0，他引：1
南海自然地理环境优越，生物资源丰富，渔场广阔，为发展海洋渔业提供了有利的条件和良好的物质基础。南海渔民在长期的生产实践中，根据资源和渔场的特点，开发出各种具有南海特色的适应性渔具渔法，大大地推动着南海区海洋渔业飞速发展。 相似文献
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本文探讨了中国渔船在印度尼西亚海域使用的拖网渔具,从渔具使用规格、缩结状态和结构等方面进行了分析,指出这类渔具在浅水渔场捕捞带鱼时有良好适应性,但局部配纲不当,网具贴底程度未达到最佳状态。由于网目大,有些局部改革可能导致敏感的负面反应。作者认为,这类网具今后的改革应着眼于提高拖速,以增加对某些优质鱼的兼捕比例。 相似文献
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Three-dimensional underwater shape measurement of tuna longline using ultrasonic positioning system and ORBCOMM buoy 总被引：1，自引：0，他引：1
Yoshinori Miyamoto Keiichi Uchida Reiko Orii Zhen Wen Daisuke Shiode Toshiharu Kakihara 《Fisheries Science》2006,72(1):63-68
ABSTRACT: The installation depth of the hook in longline fishing gear has previously been measured with micro depth loggers. Research that assumes the catenary shape of longline fishing gear by a simulation based on these data has been done. However, it was not known whether the branch line was tangled with the main line or flowed with the current. In this research, an ultrasonic positioning system generally used to investigate the underwater behavior of marine organisms, and a buoy with a communications satellite, have been used, and the 3-dimensional underwater shape of tuna longline fishing gear was measured. It was possible to monitor changes in fishing gear in real time. The possibility of high precision measurement was suggested with future technical improvement. 相似文献
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Gebremeskel Eshetu Kebede Chun Woo Lee Subong Park Mun Kwan Kim 《Fisheries Science》2018,84(6):939-952
We investigated the underwater shapes of trolling lines for the improvement of hairtail fishing efficiency. Two sets of experiments were carried out, one on a small scale, where flume tank tests of four models were scaled down by a ratio of 1:10 and trolled at different speeds, and another at full scale, comprising a survey on board a commercial fleet. In situ trials were conducted off the coast of Jeju Island, South Korea, at 33°27′57.528″N, 126°55′48.846″E, a potential fishing ground for hairtail fishing. The full-scale gear was set by altering sinker weights whilst changing the length of the warp line at different towing speeds. A dynamic method using a mass-spring technique and full-scale gear was developed. External and internal forces that govern the motion of the gear were considered. A non-linear differential equation of motion was developed, solved by a fourth-order Runge–Kutta method at a time step of 5?×?10?4 s for each trial. A static method was also developed using full-scale gear to predict the equilibrium gear configuration under all fishing conditions. The dynamic method better predicts the actual underwater performance of trolling line gear in real time. 相似文献
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ABSTRACT: The underwater shape and hook depth of tuna longline gear are important factors determining fishing performance. In this study, how the shape of tuna longline gear changes in response to sea conditions and gear rigging is explained. Physical models of underwater gear shape were made to simulate fishing gear and analyzed according to the direction and velocity of currents. Then experiments with small-scale models were conducted in a flume tank to confirm the accuracy of the simulation analysis. Finally, the simulation was examined relative to actual longline fishing gear. This approach provided an improvement over previous analytical methods that did not consider fishing gear shape in response to different sea conditions. A useful result is an improved understanding of the relationship between ocean currents and the configuration of longline gear (the shortening ratio, and number of hooks per basket). These factors affect hook depth which, in turn, affects selectivity. Application of these results could lead to more effective and efficient fishing under different sea conditions. 相似文献
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Abandoned, lost or otherwise discarded fishing gear (ALDFG) represents a significant, yet ultimately unknown amount of global marine debris, with serious environmental and socioeconomic impacts. This study reviews 68 publications from 1975 to 2017 that contain quantitative information about fishing gear losses. Gear loss estimates reported by the studies ranged widely, with all net studies reviewed reporting annual gear loss rates from 0% to 79.8%, all trap studies reporting gear loss rates from 0% to 88%, and all line studies reporting gear loss rates from 0.1% to 79.2%. Information obtained from this review was used to perform a meta‐analysis that provides the first synthetic, statistically robust estimates of global fishing gear losses. The meta‐analysis estimates global fishing gear losses for different major gear types. We estimate that 5.7% of all fishing nets, 8.6% of all traps, and 29% of all lines are lost around the world each year. Furthermore, we identified key gear characteristics, operational aspects and environmental contexts that influence gear loss. These estimates can be used to support sustainable fisheries development through informing risk assessments for fisheries and monitoring and assessment efforts to reduce gear losses. 相似文献
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幼鱼及非目标种类兼捕已成为许多网具作业共同存在的问题,提高网具选择性能是降低这种兼捕的重要途径。但是选择性能研究主要是基于从网具中逃逸后的鱼类较轻遭受到网具损害并最终存活。如果逃逸死亡率较高,即使选择性提高也是无宜的,因此应当将鱼类逃逸后生存能力作为网具改进效果的评价指标。本文主要由以下三个部分组成:(1)逃逸后死亡的主要影响因素概述,主要包括网具特征、作业时间、作业深度、渔获种类及体长、渔获量及环境因子等;(2)逃逸死亡对资源量和渔业管理决策的影响;(3)总结了近年来通过网具革新措施提高存活率的最新研究概况,如逃逸网片、分离栅及新型材料的应用等。综合分析,认为采取保护幼鱼和非目标种类的一系列措施尽管能够提高鱼类从网具的逃逸几率,但是并不能降低遭遇网具的概率,实施禁渔区、禁渔期制度管理,避免在幼鱼资源高密度区和产卵季节作业是降低这种未报告死亡的最重要的途径。 相似文献
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Leokadia Swierzowska 《Aquaculture (Amsterdam, Netherlands)》1980,20(1):71-75
The paper discusses briefly eel exploitation and traditional methods of catching eel. Attention is drawn to changes taking place in eel exploitation in Polish lakes, and to their causes. Most effective methods of eel catching are reviewed. It is pointed out that utilization of active fishing gear, mainly seine nets and electric aggregates, creates significant possibilities of increasing eel catches. Eel yields up to 40 kg/ha are not unusual with this type of gear. Furthermore, active fishing gear is more effective and can be used also in lakes in which it is difficult to apply traditional eel traps. The latter fact is of special significance in view of the increasing number of lakes stocked with eel, and improvement of eel stocking effectiveness. 相似文献
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- 1. Artisanal fishing on coral reefs in Papua New Guinea is an important livelihood activity that is managed primarily at the level of local communities. Pockets of overexploitation exist and are expected to increase with plans for increased commercialization.
- 2. This paper provides a current assessment of the artisanal multi‐species coral reef fishery by examining selectivity of the dominant gear, namely line fishing, spearguns, and gill nets. Each gear has its own strengths and weaknesses in terms of use and conservation of resources, with no clear problem gear.
- 3. The three gears utilize different resources but there was moderate overlap in the species caught, particularly between gill nets and line fishing and marginally between lines and spearguns. Gill nets have the disadvantage of being destructive to coral and the advantage of catching commercial species. Line fishing catches an intermediate number of species but mostly large‐bodied and predatory species that could potentially reduce predation and the mean trophic level of the fishery. Spearguns catch the highest numbers of species, including many non‐commercial and herbivorous fish and could reduce the diversity of fish and encourage algal growth.
- 4. This information could be used in combination with scientific monitoring and traditional ecological knowledge to develop an adaptive management framework that uses local restrictions on the various gears to restore or balance the fishery and ecosystem. Restrictions could be selectively imposed: on gill nets when coral cover is low, line fishing when large‐bodied predators are depleted, and spearguns when biodiversity is reduced and algal abundance high.
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帆式张网是东海渔业区的主要捕捞作业渔具。本论文根据37艘不同功率帆式张网渔船1999－2000年的渔业生产实态，按功率大小分类汇总了不同渔船生产成本，非生产成本，产值和利润等经济指标，比较分析了不同功率渔船的成本和效益。同时，还讨论了税费和资金成本对渔船经济效益的影响，比较分析了不同功率渔船的经营效果。 相似文献
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利用几何相似原理将传统的过滤性渔具选择性曲线转化为选择性曲面。运用选择性方程，并假设不同网目大小的渔具对相同尺寸渔获个体的渔获服从多项分布后，对过滤性渔具的网目选择性建立模型。使用极大似然估计法对模型进行拟合，同时，通过假设检验对模型进行简化。使用平行作业法试验条件下的张网渔具的黄鲫(Setipinrm taty)渔获数据进行模型拟合。结果显示，所建模型可以在没有对照网的情况下估算出各不同网目大小网囊的选择率，并同样适用于套网法试验条件下的选择性分析。模型的建立为今后进行过滤性渔具网目选择性试验方法改革提供了理论参考。通过与SELECT模型比较，认为模型使用选择性方程并区分渔获能力和捕捞努力量使得模型更具普遍性。 相似文献