栉孔扇贝夏季大规模死亡的神经网络（ANN）预测模型

根据2002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（ANN）的原理和误差反相传播（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0.0091。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％。本研究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。     

栉孔扇贝病害防治技术

栉孔扇贝是我国北方海水养殖的主要品种,近些年来在生产上遇到的一个重要问题是病害,给生产造成很大损失,为了解决这个难题,我们从1985—1991年对长岛水域养殖的栉孔扇贝的病害进行了调查研究,认为防治扇贝死亡主要应采取以下防治方法: 1.秋天拣苗暂养时间应在10月上旬开始到11月中旬结束,拣苗过程中,动作要快,干露时间要短,一般不超过一小时。拣     

胶州湾栉孔扇贝大规模死亡的流行病学调查

2 0 0 0年 1月 - 12月 ,跟踪调查了胶州湾养殖栉孔扇贝大规模死亡情况 ,对养殖海域环境因子进行了测定 ,并对大规模死亡期间发病栉孔扇贝进行了病理学观察。调查结果显示 ,胶州湾养殖栉孔扇贝大规模死亡呈暴发性并集中在 7月下旬的高水温期。发病高峰期在 7月 2 1日至 7月 2 7日 ,最高时点患病率达 14 .5 % ,7月份的月死亡率为 5 8.0 %。至 8月 3日累积死亡率达 90 .0 % ,患病贝死亡率接近 10 0 %。发病期扇贝壳高平均为 5 .0± 0 .9cm。,养殖栉孔扇贝半数死亡时间在 7月 2 3日。通过对水环境因子、病原性生物因子的调查分析及病理学观察表明 ,栉孔扇贝的大规模死亡可能是由生物性因子 (病毒 )所致 ,而与环境中理化因子可能无直接的相关关系     

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。     

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     

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…     

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.     

Selection of a new scallop strain,QN‐2, from the backcross of Peruvian scallop × bay scallop F1 hybrids with bay scallops

Cross‐breeding has been successfully applied in agriculture and aquaculture industries to improve important production traits. In our previous studies, we produced the F₁ hybrids with high heterosis in growth by crossing the bay scallops with the Peruvian scallops and selected a new strain, Bohai Red, from the F₁ hybrids. In this study, we selected another new strain from the backcross (BC₁) of the F₁ hybrids with bay scallops. The base cohort (G₀) was size‐selected from the BC₁, and the G₁, G₂, G₃ and G₄ cohorts were produced with size‐selected brood stocks from the G₀, G₁, G₂ and G₃ cohorts respectively. Our results showed that average shell height, shell length, shell width and whole body weight of the G₄ cohort were increased by 16.8%, 16.8%, 11.5% and 43.6%, respectively, compared with the unselected control group of bay scallop. This new strain has now become one of the major cultured Argopecten scallops in northern China waters and was later named QN‐2.     

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。     

主养草鱼与主养黄颡鱼池塘沉积物—水界面氮磷营养盐通量变化及与环境因子的关系

为了探讨不同主养模式池塘养殖期间沉积物—水界面氮磷营养盐通量变化特征以及与环境因子之间的相互关系,利用沉积物—水界面营养盐扩散通量的原位观测装置,分析了2013年4—10月主养草鱼和主养黄颡鱼池塘沉积物—水界面营养盐交换通量,并探讨了影响营养盐交换通量的因素。结果发现:(1)在养殖初期,各种形态氮磷在养殖池塘沉积物—水界面主要表现为从上覆水向沉积物的沉积,养殖中后期,由于温度升高以及池塘沉积物中营养物质的大量累积,各种形态氮磷表现为以沉积物向上覆水扩散为主,表明池塘沉积物是氮磷营养盐的源与汇;(2)两种不同主养模式池塘氮磷通量的统计结果表明,沉积物—水界面-N、-N和-P通量变化无显著差异,而-N、TN和TP通量有显著差异;(3)上覆水中DO含量的升高显著促进界面间-N和-N释放通量,而-N和-P释放通量与上覆水DO浓度成显著负相关;温度的升高对各种无机形态的氮磷通量有显著的促进作用。     

Enzymatic Hydrolysis of Alaska Pollock Proteins Based on Kinetics Model and Lysine Biosensor–Neural Network Model

Controlled proteolysis is important for target hydrolysates. The hydrolysis kinetics of pollock bone protein (PBP) was obtained by mathematic deduction and experimental analysis. The equation of degree of hydrolysis was as follows: DH = 2.801 ln|1 + (0.06044E₀/S₀?0.1005)t|, which could predict the hydrolysis process of PBP when hydrolysis condition was strictly controlled. However, the hydrolysis reaction was affected by several factors, and the predicted value may be against the experimental result. Therefore, online monitoring was necessary for obtaining the target peptides. Biosensor and artificial neural network (ANN) were employed for monitoring hydrolysis process online. Free lysine level was chosen as the monitoring factor determined by immobilized lysine oxidase electrodes. Based on the lysine biosensor and ANN, the hydrolysis monitoring model LYS-ANN was built, including 3 input layer nodes (E₀, S₀, and LYS), 1 output layer node (DH), and 11 hidden layer nodes. R² value between sample value and simulation value was 0.9964. Simulation error was in the range of 0–4.56%, and the average relative error was 0.94%. The verification tests of PBP hydrolysis showed that the LYS-ANN model could forecast hydrolysis process successfully with high efficiency and accuracy even if the hydrolysis conditions varied.     

Mathematical model for goldfish recirculating aquaculture system (GRAS)

A mathematical model is framed for a goldfish recirculating aquaculture system based on unsteady-state mass balance for prediction of the concentration of total ammonia nitrogen (TAN), nitrite-nitrogen (NO₂-N), nitrate-nitrogen (NO₃-N), dissolved oxygen (DO) and total suspended solids (TSS). The goldfish were stocked at 100 numbers per m³ of rearing water volume of 5 m³ tank capacity in the years 2009 and 2010 and the model was calibrated and validated. The recirculation flow rate was fixed at 29,000 L/day. The model parameters were estimated as k_TAN (mg of TAN generated per kg of feed): 20,000, M (mortality rate): 0.002 day⁻¹, α (percentage of feed conversion to suspended solids): 23.8, k_oxy (mg of oxygen required for fish respiration per kg of feed applied in unit time): 300,000, k_b (partial nitrification in the culture tank): 0.86 and the reaction rate constants, k₁ and k₂: 84.65 day⁻¹ and 42.03 day⁻¹ respectively and temperature growth coefficient (TGC): 5.00 × 10^-5. The model efficacy was adjudged by estimation of the coefficient of determination (R²), root mean square error (RMSE), Nash-Sutcliffe modelling efficiency (E_NS) and graphical plots between predicted and observed values.     

凡纳滨对虾养殖塘叶绿素a与水质因子的多元回归分析

2009年4-9月期间,对上海市奉贤区某凡纳滨对虾养殖场22个养殖池塘水体叶绿素a、水温、pH、溶解氧、透明度、悬浮物(SS)、总有机碳(TOC)、五日生化需氧量(BOD₅)、高锰酸盐指数(COD_Mn)等15项水质因子进行测定。取164组测定数据,进行描述性统计,分析叶绿素a与各项因子的相关性系数。分析结果显示,与叶绿素a呈极显著线性正相关的水质因子为SS、TOC、BOD₅、COD_Mn、TN、TP;呈显著正相关的为DO;而叶绿素a与透明度呈极显著线性负相关,与PO^3-₄-P呈显著线性负相关;与水温、pH、NO^-₂-N、 NO^-₃-N、NH₃-N则未呈现显著相关性。根据多元线性回归选择自变量的原则,选择了TOC、TN、PO^3-₄-P和TP₄项水质因子,建立了叶绿素a与4项水质因子的逐步回归模型:Chl.a =-0.054 5+0.0034 9 TOC+0.015 3 TN-0.418 PO^3-₄-P+0.276 TP(r=0.715 5)。利用偏回归系数检验各水质因子对叶绿素a的影响,结果表明,对叶绿素a影响从大到小依次是TP、TOC、PO^3-₄-P和TN。研究结果对进一步探讨养殖池塘生态系统的变化规律及水环境质量保护提供了依据。     

Assessing the population transmission dynamics of tilapia lake virus in farmed tilapia

A novel virus, tilapia lake virus (TiLV), has been identified as a key pathogen responsible for disease outbreak and mass mortality of farmed tilapia. We used a deterministic susceptible‐infectious‐mortality (SIM) model to derive key disease information appraised with published TiLV‐induced cumulative mortality data. The relationship between tilapia mortality and TiLV exposure dosages was described by the Hill model. Furthermore, a disease control model was proposed to determine the status of controlled TiLV infection using a parsimonious control reproduction number (R_C)‐control line criterion. Results showed that the key disease determinants of transmission rate and basic reproduction number (R₀) could be derived. The median R₀ estimate was 2.59 in a cohabitation setting with 2.6 × 10⁵ TCID50 fish^?1 TiLV. The present R_C‐control model can be employed to determine whether TiLV containment is feasible in an outbreak farm by quantifying the current level of transmission. The SIM model can then be applied to predict what additional control is required to manage R_C < 1. We offer valuable tools for aquaculture engineers and public health scientists the mechanistic‐based assessment that allows a more rigorous evaluation of different control strategies to reduce waterborne diseases in aquaculture farming systems.     

Aquaculture wastewater quality improvement by water spinach (Ipomoea aquatica Forsskal) floating bed and ecological benefit assessment in ecological agriculture district

The current ecological situation of aquaculture water quality in Wushe (Songjiang district, Shanghai city) district is not up to mark. In the present study, characteristic of ecological agriculture park was first investigated and then water spinach floating bed was used to improve the aquaculture wastewater quality. The results showed significant improvement in the aquaculture water quality at the experimental site with removal rates of TN, NH₄⁺-N, NO₂⁻-N and TP were 11.2%, 60.0%, 60.2% and 27.3%, respectively. Moreover, we found that the removal mechanism of ammonia nitrogen and nitrate nitrogen by water spinach was mostly by microorganism, whereas the removal mechanism of phosphorus was mainly by plant absorption. In addition, water spinach could be harvested at regular time intervals, which could achieve good economic benefits. This research could provide a good case study for sustainable development in ecological agricultural park for other cities around the world.