栉孔扇贝夏季大规模死亡的神经网络预测模型

根据2002年和2003年对山东荣成桑沟湾栉孔扇贝养殖海区的水温、盐度、pH、氨氮浓度、亚硝氮浓度等环境因子和扇贝血清中的蛋白浓度、酸性磷酸酶活力、碱性磷酸酶活力、超氧化物歧化酶活力和过氧化氢酶活力等免疫学指标及栉孔扇贝养殖密度和死亡率的监测数据,运用人工神经网络(artificial neurd network,ANN)的原理和误差反相传播(back propagefion,BP)网络的方法,利用MATLAB软件初步建立养殖栉孔扇贝夏季大规模死亡的BP人工神经网络预测模型.预测模型经过300次的学习训练,误差平方和由67.46下降至0.009 1.该预测模型对未参与模型构建的样本预测的结果与实际监测结果的符合率达到87.5%.首次将人工神经网络与水产动物病害死亡的预测相结合,建立的预测模型具有对数据适应能力强,可适时学习,预测结果准确等突出优点,为水产养殖动物病害死亡程度的预测提供了一个新的研究方法.     

一种RNA球形病毒是导致栉孔扇贝大规模死亡的直接病原

本刊讯：栉孔扇贝养殖是我国沿海地区主要的支柱性产业。自1997年起，连续几年暴发的大规模死亡症，导致了该产业的巨大损失。中国水科院黄海水产研究所栉孔扇贝养殖课题组自2000年起分别从统计病学、病理学、病原学以及环境理化、生物因子等开展了深入、全面的研究，研究结果证实，一种RNA球形病毒是导致栉孔扇贝大规模死亡症的直接病原。     

栉孔扇贝病原感染与病害发生关系探讨

利用电镜负染技术检测自然海区养殖和人工感染试验的栉孔扇贝组织提取液,分别发现病毒和类立克次氏体(RLO)两种病原体。动态检测两类病原体感染状况与整个养殖期间栉孔扇贝发病死亡情况,结果表明,养殖期间病毒感染率在80％—100％之间,最大感染强度出现在栉孔扇贝大规模死亡的7、8月份。人工感染病毒的栉孔扇贝,其病毒感染率和感染强度与养殖栉孔扇贝大规模死亡时期相当。而两种情况下栉孔扇贝类立克次氏体的感染率和感染强度均未见明显变化。综合分析表明,病毒可能是造成栉孔扇贝大规模死亡的直接病原体。     

栉孔扇贝死亡的主导原因及其对策

1997、1998两年,山东省和辽宁省沿海养殖的栉孔扇贝发生大规模死亡,许多海区绝产,造成的经济损失超过20亿元,给沿海渔业经济造成了很大的困难。实际上,早在1997年之前,鲁、辽沿海养殖的栉孔扇贝就不断发生较大面积的死亡,没有发生死亡的海区的栉孔扇贝也出现生长缓慢、规格小、质量低劣等问题。     

一例栉孔扇贝D形幼体大量死亡的诊治

<正>栉孔扇贝(Chlamys Farreri),具有很高的经济价值、粮食安全价值和医药价值。近年,我国贝类养殖业快速发展,在辽宁、河北、山东等地均有养殖,其产品主要出口日本、韩国和美国等国家。随着养殖规模的扩大,栉孔扇贝病害问题日益严重,在苗种的选育阶段病害问题尤为突出,导致育苗出苗率低甚至选育完全失败。近日,大连海洋大学、大连市海珍品疾病防控重点实验室接诊了一例以纤毛掉落、面盘肿胀、伸缩困难为主要病征的栉孔扇贝D形幼体大量死亡的病例,现将该病例的情况报告如下。     

加快水产优良品种选育促进苗种的健康生产

据估计,我国每年因水产养殖病害而造成的直接经济损失达百亿元之巨,且有上升的趋势。对虾病毒病在我国广大海区连续10余年的肆虐,至今还无良策可根治。自1997年以来由于球形病毒等造成的栉孔扇贝大规模死亡连年发生,其它如鲍、牡蛎、海带、紫菜等的病     

人工养殖栉孔扇贝和海湾扇贝血淋巴中部分免疫因子的比较研究

采用分光光度技术对人工养殖的栉孔扇贝和海湾扇贝血淋巴中部分免疫因子进行了比较研究。结果表明,海湾扇贝血清和血细胞中溶菌酶、非特异性酯酶(NSE)、过氧化氢酶(CAT)、髓性过氧化物酶(MPO)、一氧化氮(NO)、一氧化氮合酶(NOS)、活性氧和H2O2的活力或含量均高于栉孔扇贝,两种扇贝除血清中MPO活力差异不显著外,其他各组均差异极显著或显著。表明人工养殖海湾扇贝较栉孔扇贝的免疫力强。     

栉孔扇贝质量及其参数测定

栉孔扇贝是珍贵的海水贝类,自上世纪80年代以来,扇贝养殖已成为我国海水养殖的支柱产业之一,我国养殖扇贝约2．7万hm2（40万亩）,产量约110万t。但1997～1999年我国连续3年发生养殖扇贝大量死亡现象,死亡率高达70％-80％,造成重大经济损失,并且至今没有得到根本性转变。为了指导生产,保持该养殖品种的优良性状,做好栉孔扇贝选种育种工作,对栉孔扇贝亲贝提出质量要求和进行质量参数测定是很有必要的。     

栉孔扇贝一种球形病毒的分离纯化及其超微结构观察

栉孔扇贝是我国北方沿海贝类养殖的重要经济种类 ,目前已成为我国北方海洋经济的支柱性产业之一。但随着近年来病害的不断加剧 ,养殖期栉孔扇贝的大规模死亡现象频繁发生 ,极大地威胁着这一产业的可持续发展。因此 ,国内围绕扇贝大规模死亡的致病因子及病原学的探讨已引起养殖界各方的高度关注[1-4] 。2 0 0 0年我们对山东省内主要扇贝养殖海区开展了系统的病原学和流行病学调查。通过病贝组织超薄切片的电镜观察 ,在病害高发期的病贝体内大量发现一种球形病毒样颗粒。在此基础上 ,我们进一步完成了该病毒粒子的分离和纯化 ,现将有关结果报…     

栉孔扇贝换季养殖方法

近几年来，山东省日照市东港区浅海筏式养殖的栉孔扇贝连续几年出现大面积的死亡现象，死亡率高达９０％，部分海区甚至绝产。针对这种情况，我们及时进行了养殖结构的调整，推广栉孔扇贝的换季养殖，就是改变“春放秋收”的传统养殖方式为“秋放春收”，避开夏季高温死亡期和台风期，有效地制止了浅海养殖栉孔扇贝的滑坡现象，取得了较好的经济效益。现把我区林孔扇贝换季养殖的做法介绍如下： １、海区及器材养殖海区和养殖器材均与原养殖方式相同。 ２、苗种栉孔扇贝换季养殖的关键因素之一是购得大规格的苗种。大规格扇贝苗来源有二种，…     

神经网络在养殖水质精准预测方面的研究进展

目前神经网络研究文献成果较多，虽然在水质精准预测方面起到了一定的参考，但由于文献缺少科学分类，使用率不高，导致学者难以找到研究切入点。针对这一问题，本文将神经网络方法在养殖区水质精准预测方面的文献按照海水和淡水两大领域进行分类，主要对每个领域所应用的预测模型从正反馈架构、循环架构和混合架构三个方向对海水时空序列文献进行分类研究和综述，发现混合架构模型的预测性能优于正反馈模型和循环架构模型，有利于提升不同深度水质预测模型的精度。另外，本文对基于神经网络方法的三维水质预测模型进行了初步探讨，发现学者的研究成果更多地集中在水表层和水中层的不同位置水质参数的变化方面，而神经网络方法对水表层水质预测精度比水中层和水深层水质预测精度高。     

A BIOECONOMIC MODEL FOR CHAM SCALLOP (PATINOPECTEN YESSOENSIS) AQUACULTURE IN KOREA

A bioeconomic model of cham scallop aquaculture in Korea was used to determine an optimal farm grow-out strategy. The model used estimated cost functions for two culture methods and growth functions based on three environmental characteristics for each region (Kojin and Chumunjin). Stochastic growth was incorporated using probabilities of alternative environmental states (based on expected levels of water temperature, salinity, and dissolved oxygen) by region, culture method, and month. The model revealed a 26% potential increase in net present value from altering management of a single rotation. Optimal multiple rotations required up to four different rotations depending on the region and culture style. Farmers could increase economic returns by delaying harvest and subsequent plantings in order to market larger, more valuable scallops. Resource managers could increase resource rents by adjusting the licensing system to account for regional-style differences and by targeting the planned aquaculture investments.     

池塘植藕对沉积物养分和酶活性的影响

为了揭示池塘种植莲藕(Nelumbo nucifera)对沉积物养分吸收及其养分转化相关酶的作用效果,将基本情况完全相同的养殖池塘分为植藕组(Tl)和非植藕对照组(CK),观察2组池塘在黄颡鱼(Pelteobagrus fulvidraco)苗种培育过程沉积物中养分和4种酶(脲酶、磷酸酶、蛋白酶、蔗糖酶)活性变化。结果显示,与CK相比,Tl沉积物中的总氮(TN)、氨态氮(NH⁺₄-N)和硝态氮(NO^-₃-N)在莲藕苗期后均显著降低,在莲藕休眠期分别降低了8.5%、54.1%和52.7%,其中NH⁺₄-N减少是沉积物中TN降低的主要原因;莲藕苗期至花果期的总磷(TP)明显下降,最大降幅达22.6%;苗期后的有机质(OM)开始显著降低,休眠期相较对照组降低8.4%。对2组池塘而言,沉积物的酶活性均呈现先增加、后降低的变化趋势,Tl沉积物中4种酶的平均活性均高于CK,酶活性的差异在莲藕苗期和休眠期达显著水平(P<0.05)。研究表明,4种酶之间存在着显著正...     

Polyculture of sea scallops (Placopecten magellanicus) suspended from salmon cages

Commercial and developmental operations for the culture of the seascallop, Placopecten magellanicus, are present in AtlanticCanada and New England. In an experiment designed to examine the commercialfeasibility of polyculture of scallops with Atlantic salmon(Salmo salar), we measured growth andsurvival of sea scallops grown in suspension at two salmon aquaculture sites innortheastern Maine (Johnson Cove (JC) and Treats Island (TI)). Sea scallop spatwere grown in pearl nets and deployed on drop lines containing ten nets inAugust 1994. One drop line of ten nets was sampled about every four months andscallops were counted, measured and weighed. Scallop tissues were also analysedfor paralytic shellfish toxins (PSP). The maximum level of PSP recorded duringthe study was 1174 g STX equiv.·100 gtissue^–1 (excluding adductor muscle weight). After one year,shell heights were 53.6 and 56.4 mm, growth rates were 0.11 and0.12 mm per day and wet adductor muscle weights were 3.3 and 4.1g (TI and JC, respectively). These growth rates were comparable tosea scallops grown in suspension culture to a nearby scallop aquaculture siteand other areas in Atlantic Canada. Reduced rates of survival were found duringthe latter part of the experiment and were attributable, in part, to heavyfouling, predators and high stocking density. The potential for supplementalincome, diversification of the salmon aquaculture industry, and feasibility ofculturing scallops at adjacent sites to salmon operations does exist.     

Suspension-feeding aquaculture systems: Effects of phytoplankton concentration and temperature on growth of the bay scallop

The growth rate of the bay scallop Argopecten irradians was studied in relation to temperature and phytoplankton concentration. Results suggest that normal variations in phytoplankton concentration do not influence the growth rate of scallops in their natural habitat. Increasing the concentration of phytoplankton above natural levels did not result in increased growth rates while decreasing the phytoplankton concentration resulted in a decrease in growth rate of the scallops. Under extremely low phytoplankton concentrations, such as those that characterize ‘clean water’ effluent from a culture system, the animals ceased growing. A mathematical model of scallop growth rate as a function of phytoplankton concentration is proposed as a tool for comparing the functioning of different suspension feeders in aquaculture systems.     

Effects of temperature on non-specific immune parameters in two scallop species: Argopecten irradians (Lamarck 1819) and Chlamys farreri (Jones & Preston 1904)

The effect of chronic (2 weeks) temperature (19, 22, 25, 28 and 31°C) on certain non‐specific immune parameters of two species of scallops, Argopecten irradians (Lamarck 1819) and Chlamys farreri (Jones & Preston 1904) were studied. The survival ratio of the two species of scallops at 31°C was the lowest. Haemocyte concentration of C. farreri in the 19 and 22°C treatment groups was significantly lower than that of the 25 and 28°C treatment groups but significantly higher than that of the 31°C treatment group. With elevation of seawater temperature, the alkaline phosphatase (ALP) and acid phosphatase (ACP) activities in sera of two scallop species increased and reached the peak at 25°C and then decreased. However, the specific activity of ALP and ACP of the 31°C treatment group was the highest. The results demonstrated that temperature of seawater significantly affected immunity of scallops. The concept that the stress of high environmental temperature on C. farreri may be partially responsible for the mass mortality of the organism is also introduced.     

封闭循环水养殖系统中池塘覆膜对水质的影响

2005—2010年,对天津市天祥水产有限公司封闭循环水养殖系统水质进行了检测。结果显示:养殖池塘是否覆膜、覆膜面积大小,均会使整个养殖系统中的总硬度(TH)、总碱度(AT)、NH3-N和PO4-P在时空上产生差异。时间上,它们年份间差异极显著(P<0.01);空间上,各采样点的AT和NH3-N差异显著(P<0.05)。覆膜使系统的TH和AT稳定性减弱,CV上升了166.5%～241.7%,这种情况在养殖中期尤为突出,但对NH3-N和PO4-P稳定性的影响并不明显。养殖系统中较大面积的覆膜(43.65%)对养殖池塘TH、AT和NH3-N稳定性的影响比非覆膜池塘的大,CV分别高出了75.9%、135.6%和21.6%;而小面积(19.2%)覆膜的养殖池塘相对非覆膜池塘稳定,CV分别降低了71.9%、41.5%和91.4%。导致它们间差异及稳定性变异的原因主要归结于覆膜影响了物质与土壤间的物质交换及其间的生物活性强度。     

Impact of short‐term climate effects and sea ice coverage variation on Japanese scallop aquaculture in Saroma Lake,Japan

Saroma Lake is the southernmost lagoon exhibiting seasonal sea ice coverage in the Northern hemisphere and one of the most important aquaculture areas for Japanese scallops (Mizuhopecten yessoensis). Under conditions of adequate food and appropriate temperature, scallops grow well from the time of ice melting in April to harvesting starting in July. However, over the past decade, Saroma Lake frequently has not been completely covered by ice in winter, and the production of Japanese scallops has shown significant changes. Therefore, this study integrated data from satellite remote sensing, buoys, and in situ observations with climatic events [the winter East Asian Monsoon (EAM) and El Niño/La Niña–Southern Oscillation events] to investigate the impact of ice coverage variations on scallop growth in Saroma Lake between 2007 and 2015. Daily ice conditions were detected using Moderate Resolution Imaging Spectroradiometer false colour images and an unsupervised classification method. The results indicated that EAM strongly influenced the ice coverage variation in Saroma Lake through their effects on temperature during winter. Ice coverage variations show a strong correlation with water temperature and spring phytoplankton blooms, which are the two most important environmental factors for scallop growth. In addition, extreme climate events could cause water temperature anomalies (as in 2015) which are unfavourable for scallop growth. Monitoring ice conditions should be considered when developing plans and management strategies for scallop aquaculture in Saroma Lake.     

3种填料对集装箱循环水养殖废水处理的初步研究

为探讨聚丙烯塑料发泡材料(EPP)、悬浮球填料和海绵填料对集装箱循环水养殖废水中细菌吸附性能的差异,以及3种填料挂膜启动和挂膜成熟后对氨氮(NH_4~+-N)、亚硝酸盐氮(NO_2~--N)和硝酸盐氮(NO_3~--N)的净水效果,以集装箱循环水养殖废水为研究对象,采用自然挂膜的方式进行了为期3个月的试验,并对相关指标进行测定。结果显示:EPP填料对养殖废水中细菌的吸附能力最好,另外两种填料对细菌的吸附能力次之并且差异不显著(P0.05);3种填料自然挂膜成熟的时间分别为21 d、26 d和30 d;各填料挂膜成熟后处理高浓度NH_4~+-N养殖废水时,NH_4~+-N浓度与NO_2~--N浓度之间的关系可以用多项式y=ax~2+bx+c进行拟合,NH_4~+-N浓度与NO_3~--N浓度之间的关系可以用对数式y=aln(x)+b进行拟合。研究表明:EPP填料、悬浮球填料和海绵填料均可作为生物填料用于集装箱循环水养殖系统。