避风型渔港避风因素浅析

我国的东南沿海是最容易遭受热带气旋影响的脆弱地带,每年的5-11月,都会遭受热带气旋的影响,对渔港、渔船和渔民构成严重威胁.而渔港的避风能力是渔民最为关心的问题,通过近几年登陆我国的强台风等级以上的热带气旋对渔港、渔船及渔民造成损失的实例分析,从防波堤设计标准、避风锚地的底质、锚泊方式等3个方面对避风型渔港的避风因素展开讨论,得到了有价值的结论,为渔港、渔船和渔民减少灾害,为政府建设避风型渔港决策提供科学依据.     

台山市重视沙堤渔港的建设

沙堤渔港是广东省五大渔港之一，位于台山市是川岛西南端，是避风补给的天然良港。港口距南海渔场较近，渔业资源丰富，港池面积2平方公里，水深10米，可供5至10万吨级轮船停泊。每年进入该渔港补给、避风的国内外和台、港、澳渔船达20万船次。     

烟台又一国家级中心渔港项目获批

日前，烟台市长岛中心渔港建设项目初步设计获得国家农业部批复，这是烟台市继蓬莱、牟平养马岛中心渔港之后第三座国家级中心渔港。该项目概算总投资4660万元，其中，中央预算内资金2900万元，地方配套资金1760万元。项目建设内容主要包括：建设防波堤兼码头350m、防波堤150m、护岸190m、     

广东全面推进标准渔港体系建设

本刊讯 广东省在十年渔港建设人大议案基础上,全面推动标准渔港体系建设,从2009年起连续5年,建设100个标准渔港,为全省6多万艘渔船,100多万渔民构筑平安港、幸福港,得到了各地政府、渔民群众的充分肯定.广东省主要通过财政支持、简化审批、减免费用等多项举措,以现有渔港的改造、扩容、升级为重点,以提高避风能力为核心,增加有效避风港池面积,完善渔港配套设施,全面提高渔港建设等级.     

广东最美渔港

<正>不仅是渔船的避风地还有令人向往的风景今年四月召开的全国渔船渔港综合管理改革现场会议指出,渔港是今后渔业管理的主战场。要充分发挥渔港在渔业资源管理、安全监管、产业兴旺和渔区振兴中的特殊关键作用,推动渔港渔村振兴。广东省沿海现有各类渔港136座,在完善渔港管理体制,加快推进渔港信息化管理建     

农业部国家安全监管总局联合部署开展“文明渔港”创建活动

渔港是渔民生产生活的重要场所和渔船避风停泊的主要基地,是渔业安全生产的重要基础环节。为进一步提高渔港管理和服务水平,保障渔船停泊安全需要,促进渔业安全生产和可持续发展,农业部、国家安全监管总局近日联合下发通知,部署开展"文明渔港"创建活动。     

浅谈渔港环境保护档案管理

正渔港是重要渔业基础设施,承载了渔获物装卸、渔需物资供给、渔船避风等诸多功能。伴随着渔港相关产业的迅速发展,渔港生产与环境保护的关系愈加紧密,有关环境保护的活动也愈加频繁。本文分析了渔港环境保护档案管理工作的重要性,立足渔港建设、运营、环保等实际情况,提出了加强渔港环境保护档案管理工作的思路和措施,更好地促进渔港生产与环境的协调统一。     

完善港务设施确保渔民渔船生产安全

渔民、渔船、渔港是渔业生产发展最活跃的重要因素，渔港是渔民、渔船赖以生存和扩大再生产活动的重要场所．必须具备渔船避风、停泊、装卸渔货、渔需物资、渔民生活补给等功能。渔港设施完善与否直接关系到广大渔民、渔船的生产安全。     

乡村振兴战略下渔港建设探究

<正>党中央国务院一直重视渔港建设在渔业发展中的作用,出台了一系列支持政策,我国渔港基础设施避风、生产、补给及辐射带动水平得到不断提升,乡村振兴战略的实施为加快现代渔港建设带来了新的机遇和挑战。本文在总结近年来我国渔港建设发展的基础上,提出从依托渔港推进建设现代渔业产业园、渔人码头、特色渔业风情小镇和渔港经济区建设四个方面着手,助力乡村振兴,并对渔港经济区建设支持体系进行了思考。     

渔港 渔区振兴的重要依托

<正>一场"广东十佳最美渔港"评选,大家都把目光聚焦在了渔港的"美"上来。其实,广东渔港不仅仅只有赏心悦目的"美",还是沿海众多中小城镇发展的重要依托,也是渔村振兴的重要抓手。众所周知,渔港是集渔船停泊与避风、渔获物装卸、物资补给、冷藏加     

Hydrodynamic responses of longline aquaculture facility with lantern nets in waves

To prevent occurrences of structure failure, it is essential to study the mooring line tension and motions of the longline aquaculture facilities with lantern nets. This study describes a physical model experiment that attempts to determine an optimal structure design. The experiment investigated effects of three facility design factors on the mooring line tension and movement of the lantern net and mainline: incident wave angles, lantern net layout depths, and lantern net layout forms (horizontal arrangement/staggered arrangement). The experimental results indicate that the mooring line tension decreases with increasing wave periods. The amplitude and variation of windward mooring line tension are much larger and more complex than that of leeward. The vertical movement amplitude and variation range of the lantern net and mainline are much larger than that of horizontal movement amplitude. Decreasing the incident wave angle, deepening the arrangement depth of lantern nets or adopting staggered arrangement can reduce the mooring line tension in the case of longer wave period. The analysis indicates that increasing the layout depths of the lantern nets and applying the staggered layout form are beneficial in reducing the vertical motion amplitude and elliptical excursion of the mainline. The incident wave angle has a relatively weak effect on the motion of the main and lantern net. Increasing the layout depths of lantern nets will reduce the horizontal and vertical movement amplitudes and elliptical excursion of the lantern nets. Changing the layout forms of the lantern nets from horizontal to staggered will increase the horizontal motion amplitude and decrease the vertical motion amplitude and elliptical excursion of the lantern nets.     

临高县深水网箱养殖存在问题及发展对策

深水网箱养殖是临高县从国外引进并因地制宜进行改造的一种新兴养殖方式,具有高投入、高风险、高产出的特点。1998年至今,临高县深水网箱养殖业经历了起始、徘徊、发展等三个阶段,深水网箱养殖集约化程度高、经济效益好、抗风浪能力强的优势得到明显发挥。在这个过程中,高成本、高风险、技术落后、布局不合理等问题日益凸显,急需政府引导企业进行技术创新、合理规划布局、多方融资、建立风险补贴和监督制度,完善深水网箱养殖产业链,建立深水网箱养殖示范基地和信息平台,助力我国水产品转型升级。     

基于FUNWAVE-TVD模型的离岸养殖围网内外波浪场数值模拟研究

本研究利用完全非线性Boussinesq数值模型FUNWAVE-TVD耦合多孔介质模型,建立了模拟围网波浪场的数值模型。将计算结果和实验数据进行对比分析,验证了该模型计算规则波在穿过网箱后传播过程的准确性。进一步研究了波高和周期等因素对围网内外波浪场特性的影响,探讨了围网波浪场特性与这些水动力因素的内在联系。结果显示,离岸养殖围网的存在使波浪场背浪侧出现衰减,波高衰减率受波浪周期影响较大,最大波高衰减达到93.3%。同时,较低频规则波的波高衰减区域呈辐射状趋势扩散,并随着波浪进一步传播,最大波高衰减位置开始向两侧扩散,围网背浪侧的波高衰减程度减小,波高有恢复趋势,而高频波浪的波高衰减区域则较为集中。本研究可为实际海域桩网围护的位置和构造提供分析依据。     

沿海地区海洋产业布局的现状评价

文章首先构建了沿海地区海洋产业发展的综合评价指标体系，运用因子分析对沿海地区海洋产业竞争力进行了评估。在此基础上，利用集中度和均衡度分析，从产业和区域两个角度进行测算，分析了全国的海洋产业布局情况，为调整海洋产业结构及优化产业布局提供政策建议。     

Experimental study on the effect of horizontal waves on netting panels

The effect of horizontal waves on flexible netting panels is examined in this study, to evaluate the testing method of pretensioned mooring, radial systems, and flexible netting structures. The netting was suspended at a specific hanging ratio for six polyethylene panels with different characteristics. The aim was to evaluate the calculation method for horizontal wave forces on flexible netting panels. A regular wave was used in the experiment, with wave period 0.8–2.0 s and wave height 50–250 mm. The force on the netting structure was recorded by a tension transducer and digital signal recorder, and was simulated by a cubic spline in terms of the wave experiment under different wave conditions. The horizontal wave force on the netting panel changed periodically and asymmetrically, which was similar to the surface wave elevation. The horizontal wave force was related to the netting panel height and width (l), wave height (H) and wave length (L), twine diameter (d) and bar length (a) of the mesh. Using dual series relations, least-squares approximation, and multiple stepwise regression analysis, the following formula was obtained for the horizontal wave average apex value (F) on the netting panel: F=0.13ρgl(H/2)²(d/a)(H ^0.64 L ^0.77/0.9a ^0.44).     

潜浮式船型桁架结构深海养殖网箱避浪性能研究

深海网箱作为现代海洋渔业拓展外海养殖空间的重要养殖装备，其布设环境一般较近海更为复杂恶劣，对于保障其安全性和稳定性提出了更高的要求。本研究针对一种单点系泊潜浮式船型桁架网箱开展了模型比尺为1︰40的波浪流水池试验，重点围绕该网箱在不同吃水深度受波浪作用的系泊受力、升沉、纵摇和横摇等水动力学特性进行了比较分析。试验结果显示，波高为7.5~12.5 cm时(原型3~5 m)，网箱漂浮状态即可以满足养殖需求，其系泊力及运动响应均较小，具备较高的安全性和稳定性；恶劣海况时，即本试验中波高为15.0和17.5 cm (原型6 m和7 m)，通过整体下潜的方式网箱具有良好的避浪性能，其中，系泊力减幅达70%以上，升沉、纵摇和横摇等运动分量减幅也达20%~60%；波流试验中，海流对网箱避浪性能存在一定的影响，但总体上仍然具有较好的避浪效果。研究结果可为单点系泊潜浮式深海网箱的安全运行与日常管理提供理论依据和数据参考。     

Biomass management in recirculating aquaculture systems using queuing networks

Queuing network contains a series of service facilities (in our case, culture tanks or ponds), at some or all of which, a customer (fish) must receive service; it is, therefore, necessary to study the entire network. A culture tank or pond can be seen as a queuing system in which neither a queue (“over-holding” of fish in tank A before being moved to tank B), nor an idle pond is allowed, and arrival and departure rates are equal. The entire farm can be seen as a queuing network. A queuing model for optimizing the management parameters of a recirculating aquaculture system was developed. The model validity was statistically tested and was not rejected within the 95% confidence level, therefore, the model can be useful for both research and practical applications. The model aims to optimize: (1) the system layout, (2) the fish batch arrival frequency, (3) the number of fingerlings in a batch, (4) the number of days in each culture tank, and (5) grading criteria along the production lines. Under our local farm conditions we found that: the “2, 4, 8 layout” was a superior layout; the optimal operating parameters were: arrival of a batch every 36 days; 72 days at the nursery stage (up to 25 g); followed by 144 days (up to 200 g) at each successive growth phase. The optimal values maintain biomass density criterion of 80 kg m^− 3 and tank utilization criterion of never below 99%.     

Water-tank experiment and static numerical analysis of the mooring system of a controllable depth cage

Recent variations in marine environments have increased the risk of aquaculture accidents at sea. This risk can be reduced by installing fish cages at the desired depth, based on environmental conditions such as wave height, the vertical profiles of water temperature, algal concentration, and dissolved oxygen concentration. Most submergible fish cages can be located at only two depths: the sea surface and a submerged depth. In the present study, a fish cage installed at various depths, i.e., a controllable depth cage (CDC), is proposed for avoiding undesirable environments. A water tank experiment is conducted to measure the drag of the cage and the static deformation of the mooring system using a scale model of the actual cage. Then, a simple numerical model based on the balance of forces on each component is developed to analyze the position and the attitude of the cage and the mooring tension of the system. The numerical model is verified by comparing the experimental and numerical results. The outcome showed that the cage and floats moved downstream at an increasing velocity. The results of the numerical simulation supported those of the water tank experiment. However, the simulated vertical positions of a cage and floats were higher compared with experimental results. Additionally, the inclination of angle increased alongside increasing velocity in the numerical simulation, whereas a complex variation was observed in the experiment. This happened because of underestimating the drag on the mooring rope in lower water current velocities; additionally, cage lift was not considered in the numerical model. Despite these discrepancies, the tension of each mooring rope was well predicted because of the dominant tension of the horizontal component. In future studies, the balance of forces on the rope should be predicted more precisely, and variations in cage drag and inclination angle should be included in the numerical model. Additionally, the effect of waves should be considered alongside water currents to ensure the safety of the CDC.     

Numerical study on wave attenuation inside and around a square array of biofouled net cages

In this study, waves propagating through a square array of 16 net cages with different levels of biofouling are numerically studied using a three-dimensional computational fluid dynamics (CFD) model. A porous-media fluid model is adopted to simulate both clean and biofouled netting of a cage array in waves. A numerical wave tank is built, and the oscillating-boundary method is adopted to generate waves. The flow motion is solved by the Navier-Stokes equations, and the free water surface is captured using the volume of fluid (VOF) method. The numerical model is validated by comparing the numerical data with corresponding experimental measurements of a net-cage model with clean netting. To analyze wave attenuation, a numerical analysis of wave elevation both inside and around the cage arrays is presented, which considers the effect of biofouling. Based on the results of the present study, the effect of biofouling on wave elevation is noticeable; the damping effect of the cage array increases with increasing level of biofouling. Furthermore, the incident angle of waves has a noticeable effect on the wave field inside and around the cage array.     

Automatic submerging and surfacing performances of model submersible fish cage system operated by air control

An automatic, submersible fish cage system using air control was developed and a set of model experiments were conducted to examine the automatic submerging characteristics of the cage. The components of the fish cage consist of a rigid frame assembly with 6 variable ballast tanks and 6 fixed ballast tanks. The variable ballast tanks were used to change the buoyancy characteristics of the system by air control so that the fish cage can either be placed at the surface or submerged. The cage is free to move vertically within a water column by adjusting the weight and the buoyancy with an air control system. The model of this system, with dimensions of 2.20 m in diameter and length and 1.04 m in net cage depth, was constructed to be 1/10 the size of the full-scale system. In the model experiments, the submerging and surfacing characteristics of the cage were regulated with measurements from a water-pressure gauge and a gyroscope incorporated into the automatic control system. Model tests were performed in a still water tank and a large wave tank to develop the algorithm required to control the cage system and to verify the ability of the automatic submersion mechanism to function. The control system was designed so that when the variable ballast tanks were flooded with water, the model descended. To raise the system, compressed air is injected into the tanks by opening the main evacuation valve on the manifold. After the required amount of compressed air is supplied, the main evacuation valves can be shut and as a result, the fish cage becomes buoyant. Measured performance results in a still water tank are then compared with calculations from a previously developed numerical technique. The submerging and surfacing characteristics of the fish cage were relatively similar to the measurements obtained with the physical model experiments using air control. The cage was submerged to a target depth when incidence wave heights were higher than the critical wave height and raised when little wave actions were detected in a wave tank. On the other hand, the cage was placed at the surface when incidence wave heights were the same as the critical wave height or lower.