深水网箱多波束水声鱼群状态监测仪的改进设计

针对离岸深水网箱养殖的鱼群安全问题,采用多波束水声技术监测鱼群状态的方法.结合信号处理技术、通用分组无线业务(GPRS)无线传输技术及串口通信技术,开发了一套多波束水声鱼群状态监测仪.监测仪完成1次网箱扫描只需5s;实现了监测数据的即采即发功能,提高了系统的实时性;改进了电路结构,降低了系统复杂度,减小了系统体积,降低...     

深水网箱鱼群监测仪换能器转向驱动机构的设计

深水网箱养殖是目前国内外海水鱼类养殖业可持续发展的总体趋势,就我省的情况而言,深水抗风浪网箱养殖已发展到99组396口。面临众多的深水养殖网箱,鱼群在网箱中的安全问题一直困扰着养殖户,比如网衣是否完好?鱼是否逃逸?鱼的摄食情况怎样?针对这些问题,厦门大学海洋学院研发出     

深水网箱需求式自动投饵装置的初步研究

深水网箱的自动化控制是我国网箱事业发展的趋势。本文对现有投饵装置进行了分析，在此基础上，设计了一种需求式自动投饵装置，旨在提高投饵效果。网箱养殖鱼群经过驯化，有求食需求时自动触动水下金属管，并通过传感器启动下料机构。该装置通过可编程控制器(PLC)实现投饵过程控制，其优点是能根据养殖鱼类需求，实时投饵，饵料利用率高，水体污染少，满足当前深水网箱自动化发展的需求。     

一种基于前视声呐的养殖网箱内鱼群数量评估方法

为准确、高效评估养殖网箱场内鱼群数量，科学指导网箱养殖，提出了一种基于前视声呐的养殖网箱内鱼群数量统计方法。方法应用时，以声呐图像处理技术为基础，首先以目标网箱内养殖鱼类在消声水池实验室的声学标定结果为依据，对前视声呐测量声图进行单个鱼体的声学图像阈值划分；其次凭借云台控制声呐旋转，对围栏区域进行遍历探测，随后将声学标定结果确定的阈值作为划分依据，将不同角度所测声学图像中鱼类进行划分、统计，估算得到整个养殖网箱内的鱼类数量；最后结合探测角度以及位置信息，得到网箱养殖区域内的鱼类空间分布特征，用于指导渔民进行后续的网箱养殖。此方法在舟山青浜岛大黄鱼养殖网箱中得以应用。结果显示：该方法估计得到的养殖网箱内大黄鱼数量与人工评估结果基本一致，经多次计算，平均相对误差仅为2.45%,且实现过程更加高效、便捷。本研究能够有效为养殖网箱提供鱼类数量信息，为亟待进行鱼类数量监管的网箱养殖产业提供科学、可靠的数量统计方法，具有广泛的应用场景。     

基于Zigbee和GPRS技术的深水网箱系缆力远程监测系统设计

为提高深水网箱安全性,研究锚泊系统系缆受力情况,提出了一种基于Zigbee和GPRS技术的深水网箱系缆力远程监测系统。该系统由传感器节点对缆绳的受力信息进行实时采集,然后将各传感器节点采集到的信息汇聚到Zigbee协调器节点,再通过GPRS网络发送到陆地监控中心,最后通过基于Visual Studio2010平台搭建的监控中心,实现数据的实时显示、分析及存储调用。模拟测试表明,该系统测量相对误差≤1.533 3%,扩展方便,能够实时、准确地监控网箱缆绳受力。该系统为网箱结构设计以及评估网箱的安全性和可靠性提供了一种监测手段。     

信息集萃

浙江省扶植深水网箱养殖研究开发今年以来 ,浙江省海洋学院承担的国家“十五”第一批“863”计划———深海抗风浪网箱研究开发项目进展顺利 ,省国产化深水网箱养殖基地正在定海长峙岛东北海域紧张有序地建设。浙江省科技厅 2 0 0 1年将国产化深水网箱及高效养殖技术研究列入重大科技攻关项目。该研究与调整海洋渔业结构 ,解决数十万浙江渔民生活出路的重大问题相一致。省党政领导要求把深水网箱设备的研制及高效养殖研究作为一项长期的研究开发任务 ,抓紧深入研究 ,迅速实现产业化 ,还提出“把舟山建成全国规模最大的深水网箱设备制造基地…     

基于无线网桥与ZigBee技术的深海网箱养殖环境监测系统

为解决传统网箱养殖水质检测周期长、实时性差、数据误差大、维修成本高等问题,设计了一种基于无线网桥与ZigBee进行数据传输的深海网箱养殖水质与环境监测系统。该系统主要通过水质传感器获取网箱内海水的温度、盐度、浊度、pH以及溶氧等水质参数,同时利用水下摄像机采集水中鱼群状况、水面环境信息等图像信息,并通过无线网桥将监测的水质参数与图像信息实时传输至岸基数据监控中心,由监控系统实时监测养殖环境参数变化,并且可以通过无线接入点向设备发送控制指令来进行相关操作,如通过控制图像采集设备的云台来实现对网箱水面或水下环境的监控。结果显示:采用该检测系统后,能实时传输图像信息和水质参数,并能实现实时远程控制;操控中心具有数据显示、历史数据查看、水质异常时声光报警等功能。该系统具有操作简便、响应快速、成本较低、可靠性高等优点,具有较好的推广应用价值。     

网箱养殖工程研究中心在浙江海洋学院成立

为了发挥高校科技优势，更好地为发展水产养殖业服务，浙江海洋学院海洋科技学院、海洋科学研究所在承担省重大科技攻关项目“国产化深水网箱设备及高效养殖技术研究”基础上，专门组建了网箱养殖工程研究中心，成为我国目前唯一从事网箱养殖工程研究的专门机构。网箱养殖工程研究中心的主要任务，一方面是为了更好地完成“国产化深水网箱设备及高效养殖技术研究”工作，另一方面是为各地开展网箱养殖尤其是深水网箱养殖进行海洋环境调查、规划养殖园区、提供养殖工程设计、提供深水网箱设备、提供简易消浪与分流设施、开展养殖技术培训、咨…     

深水网箱养殖高体鰤生长与病害防治研究

2002年10月至2003年7月在深圳鹅公湾海域对高体鰤进行了国产深水网箱养殖试验。根据项目试验情况，本对高体鰤在深水网箱的生长与环境因子的关系进行了分析，并做出了生长曲线，中还对高体鰤在深水网箱养殖过程中的主要病害症状及防治进行了研究，提出了病害防治措施。     

我国深水网箱养殖技术及发展展望（上）

深水抗风浪网箱代表着海水网箱养殖的发展方向,是国家今后重点支持的先进的海水养殖方式。为此本刊特邀国内著名的深水网箱养殖专家徐君卓教授就我国深水网箱的发展现状、养殖技术、挪威深水网箱发展情况等内容作一介绍,刊出后收到了很好的效果,很多读者纷纷来电、来函询问深水网箱的有关问题,并希望我刊能多刊登这方面的文章。我刊又邀中国水产科学研究院南海水产研究所深水网箱课题组负责人郭根喜研究员等专家重点就南海区深水网箱发展概况、深水网箱养殖适宜的养殖水域条件、深水网箱养殖技术及今后的发展前景作一系统介绍。     

深水网箱养殖中的声学监测问题探讨

针对深水网箱养殖过程出现的一些诸如网衣安全、鱼类逃逸等问题,介绍了几种类型的监测技术应用:(1)声学警戒带方式构成的被动式网衣安全监测技术,监视声纳可以是单波束,也可以是机械扫描的多波束或电子扫描的多波束,同时采用水下机器人进行巡视;(2)基于网箱中鱼的目标强度,实现对网箱中养殖品种大小、数量的统计监测,鱼的目标强度主要取决于鱼的体态特征,同时也与发射声波的波长有关;(3)数量识别技术以及饵料投饲过程中的声学监测技术,通过将声纳输出信号反馈到投饵机,实现饵料投放自动化。     

Biomonitoring using tagged sentinel fish and acoustic telemetry in commercial salmon aquaculture: A feasibility study

We tested if it is technically feasible to monitor fish in real-time in full-scale commercial fish farms using acoustic telemetry. 31 Atlantic salmon were equipped with acoustic transmitter tags containing depth sensors. Tagged fish were monitored for three months in two industrial scale sea-cages containing 180000 and 150000 fish, respectively. Each cage was fitted with two prototype acoustic receiver units designed to collect, interpret and store the information transmitted by the acoustic transmitter tags. Ten in each cage were also equipped with Data Storage Tags (DSTs) containing depth sensors to record individual-based datasets for comparison with the acoustically transmitted datasets. After compensation for sample loss caused by expected acoustic interference between the transmitter tags, the resulting dataset revealed that the receiver units collected 90–95% of the signals in both cages. Acoustic communication conditions in the sea-cages were not strongly impaired by factors such as fish density and local noise. Further, the dataset from the acoustic transmitters had comparable resolution and quality to that produced by the DSTs. However, acoustic tags provide data in real time and enable farmers to respond to the received information with farm management measures, whereas archival tags such as DSTs need to be retrieved and downloaded and hence have no real-time applications. We conclude that acoustic telemetry is feasible as a method to monitor the depth of fish in real-time commercial aquaculture.     

Observing fish interactions with marine energy turbines using acoustic cameras

Marine current energy converters such as tidal and riverine turbines have the potential to provide reliable, clean power. The risk of collision of fishes with marine energy turbines is not yet well understood, in part due to the challenges associated with observing fish at turbine sites. Turbidity and light availability can limit the effectiveness of optical sensors like video cameras, motivating the use of acoustic cameras for this task. However, challenges persist in collecting and interpreting data acquired from acoustic cameras. Given the limited number of turbine deployments to date, it is prudent to draw on the application of acoustic cameras to monitor fish in other scenarios. This article synthesizes their use for other fisheries applications to inform best practices and set realistic expectations for the results of acoustic camera monitoring at turbine sites. We discuss six key tasks performed with acoustic cameras: detecting objects, identifying objects as fish, counting fish, measuring fish, classifying fish taxonomically and analysing fish behavior. Specific challenges to monitoring fish at turbine sites are discussed. This article is intended to serve as a reference for researchers, regulators and marine energy developers on effective use of acoustic cameras to monitor fish at turbine sites. The studies detailed in this article provide evidence that, in some scenarios, acoustic cameras can be used to inform the risk of fish collision with marine energy turbines but doing so requires careful study design and data processing.     

Determining sediment properties around a marine cage farm using acoustic ground discrimination: RoxAnnTM

Sediment traps collected significant quantities of waste solids beneath marine fish cages at a fish farm site in Greece. Diver observation and the absence of dissolved hydrogen sulphide in the water overlying sediments revealed low benthic impacts despite the very low current speeds measured. An acoustic bottom discrimination system, ground-truthed by conventional remote photography, further confirmed the apparently low benthic impact at this site. These results may be explained partly by the large number of fish present around the cages feeding on farm wastes.     

Reared Atlantic salmon, Salmo salar L., in the catches of a salmon fishery on the western coast of Scotland

Abstract. Atlantic salmon, Salmo salar L., of reared origin were distinguished from putative wild fish In the catch of a single salmon fishery in western Scotland. Fish in seven day-catches made in 1990 totalling 403 individuals were assessed formally for the presence of residual fin damage resulting from culture. Fifty-eight (22%) were classed as being of reared origin, on the basis of previously established criteria. Additional examination of 54 of these fish showed the pigment canthaxanthin to be detectable in the tissues of 35 (65%), which were therefore classed as having escaped from sea cages. Among the fish in which canthaxanthin could not be detected, a further 17 individuals (31% of the total) were classed as having escaped from sea cages on the basis of scale growth patterns. Scale growth patterns in the remaining two fish (4% of the total) were consistent with their having grown in a hatchery before escape or release.     

An automatic fishing machine based on acoustic conditioning

An automatic fishing machine based on acoustic conditioning was developed and tested in a reservoir. The floating fishing machine is remotely and automatically controlled to operate an underwater speaker, a feeder and underwater cameras that monitor fish behavior in real time. An open net pen installed under the system can be automatically closed to capture gathering fish. The dynamics of fish populations in the open net pen was monitored and discussed. Fish were conditioned to associate an acoustic signal with food by classical conditioning. Periodic retraining was used to reinforce the conditioned behavior of fish freely swimming in the reservoir. Fish were captured by calling them to the fishing machine using the acoustic signal and automatically closing the net pen around them: 2.5 times more fish were captured in such capture events than in control events, in which the net pen was automatically closed without calling the fish.     

音响驯化技术在红鳍东方鲀养殖中的应用试验

网箱养鱼对水域所造成的污染,主要表现在两个方面:一是鱼的排泄物污染,二是剩余饵料造成的污染。通过对红鳍东方进行音响驯化,研究了解决剩余饵料对水域污染问题的方法,并求得了鱼类生长(体长与体重)与摄食量之间的关系曲线,从而达到减少剩余饵料沉积量,科学制定投饵量,指导网箱养殖红鳍东方快速、持续发展的目的。     

Field measurements of cage deformation using acoustic sensors

As aquaculture continues to supply an increasing share of the worldwide seafood demand, it will become critical for farmers to maximize their efficiency. Presently, the majority of marine finfish are produced in gravity type net pens which can deform when they are subjected to currents. The water velocity loading affects the overall net shape which results in net cage volume loss and consequently, increases fish stress and decreases growth rates.In this study, an acoustic method is utilized to monitor the deformation of a small-scale fish cage deployed in currents. Twelve acoustic sources and four hydrophones were deployed on and around a small scale net pen for 60 days to monitor the net cage movement and volume. Local current velocities were recorded using two current meters, one inside and one outside the net pen. Three volume approximation techniques were examined, using the positions of the acoustic sources to predict net chamber volume as it responded to the currents. A numerical model of the system was then configured, set with loads under similar water velocities and results between field measurements and the model were compared.The use of acoustic sources and hydrophones to monitor cage deformation was shown to accurately monitor net deformation. Field measurements compared well to numerical model predictions, with errors ranging from −3.8% to 32%, depending upon the number of acoustic sources employed in the volume calculations. At low water velocities, six acoustic sources were found to accurate predict the net pen volume. In higher currents, a minimum of nine acoustic sources was recommended.     

Effect of shelter acclimation on the post-release movement and putative predation mortality of hatchery-reared black-spot tuskfish <Emphasis Type="Italic">Choerodon schoenleinii</Emphasis>, determined by acoustic telemetry

In this study, the effect of shelter acclimation on the post-release movement and putative predation mortality of hatchery-reared black-spot tuskfish Choerodon schoenleinii was examined using acoustic telemetry. We acclimated four 1-year-old fish to shelters in cages before release and compared their movements with six nonacclimated fish. Since it was not possible to compare the behavioral pattern between the former and the latter fish due to the short periods the latter fish were available to be monitored, we also compared their movements with those of large nonacclimated fish that were less likely to be preyed upon. Sixty-seven percent of the nonacclimated fish showed atypical movements before the signals ceased to be detected, a pattern that suggested a predation event had occurred, whereas none of the acclimated and large nonacclimated fish showed the atypical movements. In addition, the probability of detection cessation was about 13 times lower in the acclimated than nonacclimated fish. The signal detection patterns suggest that the acclimated fish utilized night-time shelters from the first night after release, while the large nonacclimated fish started to utilize shelters several days after release. Therefore, it is likely that the shelter acclimation enhanced the shelter utilization by tuskfish, possibly decreasing post-release predation mortality.     

The effect of demand feeding on swimming speed and feeding responses in Atlantic salmon Salmo salar L., gilthead sea bream Sparus aurata L. and European sea bass Dicentrarchus labrax L. in sea cages

Abstract Using underwater cameras, data were collected on the feeding behaviour and swimming speeds of Atlantic salmon Salmo salar L., gilthead sea bream Sparus aurata L. and European sea bass Dicentrarchus labrax L. in sea cages. Comparisons were made between the behaviours of fish fed on demand using interactive feedback systems and those of fish fed under the standard feeding practice of each farm (control). In all three species, swimming speeds were similar before feeding , but they were significantly higher in the control regimes during feeding. When fed on demand, sea bass had reduced swimming speed just before and during feeding compared with that observed during the non‐feeding periods. Higher proportions of feeding fish were observed in the control regime cages than in fish fed on demand for all three species, indicating a greater feeding intensity during meals in the control regimes. This was further supported by observations of an increase in the density of sea bass in the upper water in the control cages during feeding. The results suggest decreased levels of competition between the on demand‐fed fish during feeding, which might be hypothesized to lead to improved growth and production efficiency in aquaculture.