基于图像处理的鱼卵计数方法研究

针对传统的鱼卵计数方法效率低、精度差、对鱼卵有损伤等缺点,提出了基于图像处理的鱼卵计数方法：通过Matlab软件中强大的图像处理功能,对经过Photoshop预处理的图像进行灰度化、去除噪音、二值化和形态学处理,采用连通图计数和面积计数法进行鱼卵的计数,精确性在95%以上。该方法减轻了操作者劳动强度,弥补了人视觉的不足之处,可以有效地提高工作效率和计数精度,并且可避免鱼卵损伤,有利于后续工作的开展,具有一定的理论和应用价值。     

基于荧光效应和调色板均衡化的小球藻自动计数方法研究

为实现藻类的自动计数,以小球藻为对象,提出一种基于荧光效应和调色板均衡化的小球藻自动计数方法。首先对小球藻荧光显微图像进行预处理,将真彩色小球藻荧光图像转换为256色图像,再采用调色板均衡化算法增强小球藻荧光图像对比度,并利用基于调色板的阈值分割算法将目标藻类与背景进行分割,同时进行计数。结果表明,该计数方法能够避免杂质影响,直接对藻类彩色图像进行图像增强和阈值分割,可以增强图像对比度,避免彩色图像灰度化过程中图像信息损失;采用连通区域标记方法结合连通区域的大小识别低重叠度藻类,可降低重叠藻类对计数结果的影响,从而提高小球藻的计算准确度。研究表明,该方法实现了针对藻类彩色图像的自动计数,且对小球藻的计数精度准确率达到95%以上,高于只使用灰度图像计数的方法。     

基于计算机视觉的大菱鲆鱼苗计数方法研究

对单帧大菱鲆鱼苗计数时,由于鱼苗的重叠,导致图像中的鱼苗粘连。为此采用计算机视觉的方法,提出了一种基于曲线演化的图像处理方法来解决鱼苗图像粘连问题,并完成对鱼苗的准确计数。将图像预处理后的二值化鱼苗粘连图像的轮廓曲线作为初始演化曲线,通过水平集方法对曲线进行常值演化,统计演化过程中最大轮廓曲线数作为鱼苗数量。对选取的10帧粘连比较严重的二值化鱼苗图像分别采用面积法、连通域法、曲线演化法进行分离计数研究。结果表明:曲线演化法在鱼体数目增多时仍有很好的分离计数效果,有利于使用数鱼机对鱼苗进行准确计数。     

虾苗光电计数器在国内首次研制成功

山东省海洋水产研究所组织机械、电子、生物等多学科的科技人员联合攻关,历经一年的努力,研制成功新式虾苗光电计数器。日前,山东省水产局组织专家对这项成果进行技术鉴定。该所科技人员着重对计数精度、计数速度和计数损伤等技术指标,进     

基于计算机视觉的鱼苗自动计数系统研究

为了在鱼苗的饲养、运输和销售过程中对一定数量或批量的幼苗进行精确计数,提出了一种基于计算机视觉的鱼苗自动计数系统。利用流体力学中伯努利原理(Bernoulli principle)设计了一个稳定流速的稳流水箱,使鱼苗和水一起以平稳恒定的速度流过过流计数箱体的拍摄区;使用电荷耦合元件(CCD)高速摄像头以与水流速度成比例的帧速采集图像,并传送给计算机进行图像处理;对图像进行阈值分割和目标提取后,计算出每帧图像中不重叠区域的幼苗数量,累加求得幼苗总量。结果表明,该系统计数的相对误差在15%以内,具有较高的精度。该研究不仅解决了目标粘连、连续计数和重复计数的问题,还可推广到虾苗、蟹苗等生物幼苗计数,具有通用性强、可行性好、推广范围大的特点。     

一种基于机器视觉的鱼苗自动计数方法

提出了一种基于机器视觉的鱼苗计数方法.对采集到的鱼苗灰度图像进行分析,通过数据拟合方法建立图像中鱼苗所占像素点数与鱼苗数的关系,并由此对鱼苗进行计数.采用常用的数字CCD摄像头,配合自行编写的图像处理软件,建立鱼苗计数试验系统.试验结果表明,点算图像内45尾、50尾鱼苗时,计数的准确率可达95%以上,计数时间在3 s以内.     

水流对控制虹鳟鱼卵真菌感染的作用

在鱼类养殖上,孵化用水中普遍存在的水生真菌对鱼卵的感染是一个值得重视的问题。真菌爆发感染的发生及严重程度取决于水源、水温、水中有机物含量和孵化时间的长短。一旦真菌感染发生,会迅速向健康的鱼卵蔓延(Piper等,1982)。孵化管理人员通常是采用化学药物来控制真菌对鱼卵的感染。但是,用化学药物处理不仅会提高成本,也会直接导致鱼卵死亡。因此,为了最大限度地减少对化学药物的依赖,研究它种处理培育方法是十分必要的。     

用(生物)酶分离鱼皮和鱼卵

<正> 特罗姆瑟大学所属水产学院(挪威北部)发明了能脱去鲑鱼鱼卵的外套膜,剥去枪乌贼的表皮和大西洋鲱鱼的皮和鳞片,丝毫不损伤体表的“生物刀”。这把“刀”就是从废鱼残屑中发现的消化酶,目前这些酶在工业生产上还不能正常地进行分离合成。这些酶具有破坏生物结缔组织的特性。过去在处理鲑鱼鱼卵时,都是借助机器进行剥离操作的,加     

漂流性鱼卵的孵化特性及水动力需求研究进展

明晰鱼卵运动规律是鱼类产卵场位置推算、水库生态调度和鱼类资源保护等研究的基础。尤其是对于产漂流性卵鱼类,当流水环境不足以维持鱼卵漂流时,鱼卵便下沉死亡而无法孵化成幼鱼。对照中国内陆鱼类名录,查阅了国内重要流域及地方鱼类志中有关产漂流性卵鱼类的繁殖条件,列举了典型产漂流性卵鱼类产卵水温、产卵月份和孵化时长等相关信息。针对现有鱼类志中对于鱼卵基本物理性质及鱼卵安全漂流孵化所需水动力条件几乎没有记载的情况,补充查阅了国内外相关文献,总结梳理了漂流性鱼卵安全漂流水动力条件的研究进展。一种观点认为鱼卵在水体中是否能安全漂流取决于水体的流速,另一种观点认为控制漂流性鱼卵悬浮或下沉的关键参数是湍流或剪切速度,而不是水流的线速度。现有漂流性鱼卵漂流的关键水动力条件和阈值尚有争议,仍需对鱼卵运动规律进行机理实验研究。在此基础上,总结梳理了目前国内外对鱼卵在水中漂流输移的研究方法和手段,主要是通过野外观测、室内实验和模型模拟三种方式进行。以上研究极大推进了对鱼卵运动机制的理解,但大多数研究都仅仅针对鱼卵运动规律本身进行单一的实验或模型研究,而对于如何通过水利工程生态调度创造满足漂流性鱼卵孵化所需的流水环境,提出水利水电工程生态环境效应多维调控方法是未来产漂流性卵鱼类保护研究的重要方向。     

利用two-stage GAM研究海州湾及其邻近海域小黄鱼鱼卵的时空分布特征

为分析海洋环境变化对鱼类繁殖的影响,深入了解小黄鱼(Larimichthys polyactis)补充机制,本研究基于2015 年、2017 年、2018 年 5 月海州湾及其邻近海域产卵场调查数据,利用两阶段广义可加模型(two-stage Gener-alized Additive Model)研究了小黄鱼鱼卵分布与海洋环境因子之间的关系。结果显示小黄鱼鱼卵丰度的年际变化较大,鱼卵高丰度区集中分布在 33.5°N^34.5°N、水深 10~20 m 的近岸河口区。海水温度和盐度是影响小黄鱼鱼卵分布重要的因素。鱼卵集中分布区表层温度为 17℃,表层盐度为 29.5~30.5;底层温度为 16~18℃,底层盐度为 29。水温的年际变动也影响了小黄鱼鱼卵丰度,在水温较高的年份鱼卵丰度明显较高。本研究揭示了小黄鱼鱼卵的时空分布特征和环境因子之间的关系,为小黄鱼产卵场保护区、资源量化管理等措施提供科学依据。     

Egg and larval quality of natural and induced spawns of red snapper, Lutjanus campechanus

Egg and larval quality of red snapper, Lutjanus campechanus from natural spawns of domesticated brooders and hormone-induced spawns of wild fish were compared. Eggs and larvae from natural spawns were found to be more viable in terms of fertilization, hatching and survival rate. Also, eggs from natural spawns were larger, and eggs and recently hatched larvae had larger oil-globule. These findings indicate that natural spawning of red snapper can be a sustainable and reliable source of good quality eggs.     

Reproductive biology of a hillstream catfish, Glyptothorax madraspatanum (Day), from the Garhwal, Central Himalaya, India

Abstract. This paper studies maturity and spawning tendency of a hillstream catfish, Glyptothorax madraspatanum (Day), in the Western Nayar River, Garhwal, Central Himalaya, India. The fish is a protracted spawner as it spawns only once during the limited period from July to August. Fecundity ranges from 1640 to 6830 eggs and is more closely related to ovary weight and fish weight than ovary and fish length. There was a non-significant sex ratio of 1:1·24 between males and females.     

Reproductive biology of the carp, Labeo bata (Ham.) from the River Kali,India

Spawning in Labeo bata occurs during July and August. Each individual spawns only once, with the onset of spawning directly dependent on the monsson season. Its success depends upon the access of gravid fish to a suitable spawning ground. The average fecundity is 192 785.     

斑尾复鰕虎鱼的成熟与产卵

斑尾复鰕虎鱼卵巢发育分为Ⅵ期，在繁殖季节产两次卵，属多次产卵类型。产卵期从２月开始，延续到５月，３月和４月为盛产期。在卵巢第一次成熟时进行人工繁殖，成功的可能性较大。     

冰冻杂鱼切块机精准自动控制技术研究

为提高渔业养殖效率,改变现有杂鱼块不平整和破碎率较高等缺点,研制了一种自动化程度较高的冰冻杂鱼切块机。采用变频调速技术,以通用串行通信接口通讯协议实现西门子PLC与MM440变频器通讯,用普通齿轮减速电机进行杂鱼切块宽度调节,用测距传感器进行精确测距,对射式光电计数器进行切块计数。通过PLC控制变频器参数,设置减速电机的运行参数,再运用PLC与上位机之间的串口通讯,实现良好的人机交互,从而完成切块机精准自动控制。性能测试结果显示,在额定电压400 V条件下,切块速度25~35块/min,可将600 mm×400 mm×80 mm的杂鱼板切成宽60~90 mm,宽度可调;空载状态下,功率0.26 k W,负载运行时的转速、功率、扭矩成正比。在指定宽度下,切块精度为±5%,切块个数准确。研究表明,该控制系统可靠,适合在沿海渔业养殖中应用推广。     

Effects of salinity on growth and mortality of migratory and resident forms of Eurasian perch in the Baltic Sea

Abstract – In the coastal areas of the Baltic Sea, there are two forms of perch (Perca fluviatilis). One of the forms is migratory and spawns in streams entering the Baltic Sea. The other form is resident and spawns in brackish water. Both forms utilise the coastal habitat for foraging. We examined the spawning success of the two forms in fresh and brackish water (7‰, equal to salinity in the south Baltic Sea). The experiments showed that hatching success was equally high in freshwater and in brackish water despite female origin. The survival of yellow‐sac and free swimming fry was significantly reduced in brackish water, which was independent if the fish was of migratory or brackish resident origin. Further, growth rate of perch fry was severely reduced in brackish water. The results indicate that perch has not developed any tolerance to brackish water in the young life stages. The migratory life strategy of perch can thus be explained by higher survival of fry in freshwater.     

Multiple GnRHa injections to induce successful spawning of wild caught greater amberjack (Seriola dumerili) matured in captivity

Reliable reproduction and sufficient amounts of juveniles obtained in captivity constitute a main bottleneck for mass production of greater amberjack. The aim of the present study was to combine several aspects of broodstock management and hormonal induction, to obtain a large number of high quality spawns. Captured Seriola dumerili sub‐adults were kept for three years in 10 m³ tanks. When fish were larger than 75 cm, they were individually tagged, periodically explored to determine gonad maturation and injected with gonadotropin releasing hormone analogue from June to October. A total of 15 inductions to four males and two females produced 330 821 ± 219 519 eggs/induction and a total of 22 spawns. The number of spawns and female fecundity (2.48 millions eggs/female/spawning season) were similar to those of free wild populations and higher than those previously obtained in captivity for this species. Egg quality increased from an initial low in the first two spawns in June to give, during July to October, a mean of 96.01 ± 6.50% fertilized eggs, 92.58 ± 17.56% hatched eggs, 78.66 ± 12.60% larval survival at day 3 after. These results showed that intramuscular injections of 20 μg kg^?1 body weight GnRHa under natural temperature and photoperiod conditions in the Canary Islands produced a high induction efficiency.     

Dietary vitamin C and E supplementation and reproduction of milkfish Chanos chanos Forsskal

Milkfish Chanos chanos Forsskal broodstock (11 years old, average body weight 5.23–5.73 kg) reared in 10‐m‐diameter by 3‐m‐deep floating net cages (31–36 fish per cage) at SEAFDEC AQD's Igang Marine Substation in Guimaras Island, central Philippines, were fed daily at 3% of total body weight formulated diets (36% protein, 7–8% lipid) supplemented with 0.1% vitamin C, 0.05% vitamin E, both vitamin C and E or no vitamin supplementation (control) for 3 years. Reproductive performance was assessed in an attempt to determine the optimum nutrition for successful spawning of milkfish. The total egg production, mean number of eggs per spawning, number of spawns and mean egg diameter were not affected by dietary vitamin C and E supplementation. However, broodstock given dietary supplementation of vitamin C alone or in combination with vitamin E had a higher percentage of spawns with higher (> 90%) percentage egg viability, hatching and cumulative survival rate than those of the control. Broodstock given dietary vitamin E supplementation alone had few spawns, which made the results difficult to analyse. The results confirm the essentiality of vitamin C supplementation in producing more spawns with good egg and larval quality. The production of an adequate volume of good quality eggs and larvae to support hatchery operation is necessary to offset the huge investment in broodstock development, as it takes at least 5 years for milkfish to attain sexual maturation and spawning.     

An automatic counting system for transparent pelagic fish eggs based on computer vision

Alive eggs of marine species with pelagic eggs float, while dead eggs usually sink. A non-invasive method for counting the number of floating eggs therefore gives the possibility to track survival throughout experiments. In this paper we present an automatic image analysis method for counting live pelagic eggs of marine fish. Pelagic fish eggs are typically transparent and difficult to detect in images. Current image analysis methods for counting pelagic fish eggs are therefore done on eggs transfixed in a polymer to create contrast between the eggs and the background. This kills the eggs. The main advantage of the presented method is that it is non-invasive and only requires a minimum of handling of the eggs. As case studies we collected images of Atlantic haddock (Melanogrammus aeglefinus) and Atlantic cod (Gadus morhua) eggs. The eggs in the images were manually counted for verification of the methodology. The average counting error of false positives was 6% and the average counting error of false negatives was 2%. This demonstrates that the method is objective and accurate.