日本养殖渔场赤潮的现状、发生机理及防除对策

赤潮乃植物浮游生物异常增殖引起海水变色的现象。 60年代以来 ,日本发生赤潮有次数增加 ,成因多样化及地域扩大的趋势。特别是近岸海域的赤潮造成养殖鱼贝类大量死亡 ,给水产业带来很大的危害。1　赤潮的定义及成因生物赤潮现象由古而来 ,但定义并不明确 ,各有其说。 1 966年召开的有关赤潮研究会上才正式将赤潮的定义定为“赤潮即海水中微小生物 (主要是植物浮游生物 )异常增殖 ,引起海水变色现象的总称”赤潮并非一定为红色 ,按浮游生物的种类可呈褐、绿等各种颜色。对水产生物鱼贝类也并非一定有害 ,也有无害的赤潮。有关赤潮中应有多少…     

大连湾丹麦细柱藻赤潮的主成分分析

2002年8月，在黄海北部大连湾棉花岛海域发生的丹麦细柱藻赤潮中，跟踪测定了赤潮生消过程的生物数量及各环境要素。用主成分分析的方法，分析该海域丹麦细柱藻赤潮与环境因子的相关关系。结果表明，pH、叶绿素a、水色、DO、活性磷酸盐、COD以及透明度是指示(影响)赤潮生物细胞总量的关键因子。     

赤潮生物夜光藻及其相关海水理化因子研究

赤潮是在特定的环境条件下,海水中某些浮游植物、原生动物或细菌发生暴发性增殖或高度集中而引起水体变色的一种有害生态现象,能形成赤潮的浮游生物叫赤潮生物.发生赤潮时如果只有一种赤潮生物占绝对优势,称为单相性赤潮,如果两种生物共存占优势,称为双相型赤潮.     

略谈我国的赤潮及对策

赤潮是由于海域环境条件的改变，尤其是有机污染导致海域富营养化，促使浮游生物，特别是微小的藻类细胞异常增殖和聚集，引起海水变色，危及鱼、虾、贝和藻等的一种生态异常现象。我国最早有关赤潮的记载是1933年。解放后，渤，黄、东、南海邻近港湾均陆续有过赤潮的报道。香港地区，1975-1984年共发生84次赤潮，     

海水养殖环境赤潮生物的发生与控制

近年来赤潮的发生越来越频繁,危害也越来越大。我们在海洋调查的基础上发现我省沿海海域主要有17种造成赤潮的浮游生物,而在养殖池中发现的赤潮生物有23种。针对如潮发生的生物化学因子,我们试用天然沸石粉和化学药品相混合,制成混合药剂用来改善养殖池水环境,控制赤潮的发生取得了一定的效果。     

饶平县发生罕见的赤潮

赤潮是由于某些浮游生物急剧地繁殖或高度集结，使水体变色、带粘性和腥臭味等，渔民称为“臭水”或“赤水”。不同的赤潮生物引起的赤潮颜色各不相同。由夜光虫引起的赤潮呈粉红色；由某些双鞭毛虫引起的赤潮呈绿色；由蓝藻毛的淡红束毛藻引起的赤潮呈黄褐色；由蓝藻类的淡红束毛藻引起的赤潮呈黄褐色。     

日本研究赤潮引起的鱼类死因

日本长崎大学水产学部和医学部组成的“赤潮引起的鱼类死因研究小组”已查明赤潮致使鱼类死亡的原因是鳃部受浮游生物的侵害，而发生组织病变，窒息而死。有关赤潮的研究，以往只是以研究发生赤潮的环境条件及防止发生为主的，而对引起鱼类窒息死亡的生理机制，原因物质，     

密度流扩散装置对闭锁海域的搅拌净化

光照、特别是夏季造成海域垂直方向的温度差,从而会形成不同的密度差层,使海水上下循环受阻.这样从河川流入的有机物极易造成富营养污染,表层因强阳光和丰富营养盐使赤潮和微胞藻等植物浮游生物疯长,底部却因细菌分解有机物耗氧而处于贫氧状态.贫氧水团与污泥反应产生硫化氢等使生物无法生存,特别在海洋内湾、湖沼等与外部水交换困难的闭锁性水域更易引起污染.     

南海北部湾主要鱼类食物网

1997-2000年在南海北部湾渔场调查中搜集了49种鱼，共计2080尾。对其食性分析，并依其食料生物的生态类群以及消化器官特点，将其划分为5种食性类型：浮游生物食性、底栖生物食性、游泳动物食性、浮游生物兼底栖生物食性、底栖生物兼游泳动物食性。根据食物网中各营养级的相互关系，初步将这49种鱼划分为3个营养级：（1）草食性动物和杂食性动物，营养级分别为1．0～1．3级和1．4～1．9级。（2）低级肉食性动物和中级肉食性动物，营养级分别为2．0-2．8级和2．9～3．4级。其中，属于低级肉食性营养级的种类数量最多，共有30种；属于中级肉食性营养级的种类较少，共有12种。（3）高级肉食性动物，营养级为3．5～4．0级。属于该营养级的种类数量最少，只有7种。     

赤潮现象及其对养虾的危害

由于一些单细胞浮游生物的大量繁殖并高密度集中所引起的海水变色现象,称为“赤潮”。赤潮的海水并不一定都呈现红色,不同的赤潮生物种群所引起的赤潮颜色也不相同,但在赤潮盛期一般都伴随着明显     

Muscle activity as a key indicator of welfare in farmed European sea bass (Dicentrarchus labrax L. 1758)

Groups of adult sea bass were reared at either low (10 kg m^?3) or high (50 kg m^?3) stocking densities respectively for 84 and 116 days. To monitor the red muscle activity, about 20 fish from both densities were surgically implanted with EMG (Electromyograms) radio transmitters, after EMG calibration during exhaustive swimming exercise (U_crit test). Blood samples and morphometric measurements were also taken. EMG showed that the muscle activity of fish reared at 50 kg m^?3 was on average twofold higher than fish kept at lower density. Cortisol was significantly more elevated at higher density and haemoglobin, haematocrit and RBCC (red blood cells count) showed the same trend, while lysozyme decreased. Patterns for glucose and lactate were less clear. The results showed that the contemporary use of functional (EMG) and physiological (haematological and biochemical) profiles could give a more comprehensive view of the fish status validating the diagnosis of fish stress induced by culture practices.     

Non‐permissive C6/36 cell culture for the Australian isolate of Macrobrachium rosenbergii nodavirus

Macrobrachium rosenbergii nodavirus (MrNV) that causes white tail disease (WTD) is an emerging disease that contributes to serious production losses in Macrobrachium hatcheries worldwide. Mosquito cell lines (C6/36) have been reported to support the growth of MrNV and used to observe the cytopathic effects (CPE) in infected cells. This study determined the susceptibility of C6/36 mosquito cells to the Australian isolate of MrNV in order to use fewer animals in further investigations. Different staining methods were used to observe MrNV viral activity in C6/36 cells. Typical cytopathic effects such as vacuolation and viral inclusion bodies were observed in infected C6/36 cells with H&E and Giemsa staining. With acridine orange, it was easier to detect presumptive MrNV messenger ribonucleic acid in the infected cells. Using neutral red staining to measure mitochondrial activity showed light absorption of infected cells maximized at day 4 (O.D. = 0.6) but was significantly lower (chi‐square = 41.265, df = 1, P < 0.05) than control groups (O.D. = 2) which maximized at day 12. Using trypan blue staining to count the number of cells with disrupted cell membranes, the maximum number of presumptively dead cells at day 8 (4 × 10⁵ cells) in infected treatments was higher than the control treatment at day 10 (1.8 × 10⁵ cells). However, TaqMan real‐time PCR did not confirm the replication of MrNV in the cells over 14 days. The mean viral copies and mean cycle times of positive samples were stable at 2.07 × 10⁴ and 24.12, respectively. Limited evidence of viral replication was observed during four serial passages. This study determined the mortality of the C6/36 cell line to the Australian isolate of MrNV but suggests limited patent replication was occurring. Trying different cell lines or adapting the virus to the C6/36 cells may be necessary to successfully replicate Australian MrNV in cell lines.     

The isolation of intestinal microflora of farmed red seabream (Pagrus major) and black seabream (Acanthopagrus schlegeli) at larval and juvenile stages

The aerobic bacterial flora in the intestine of farmed red seabream and black seabream was investigated at their larval and juvenile stages in relation to the microflora of ambient water and diets. The total bacterial number in the intestine was 7.4×10⁴ and 3.4×10⁴ colony-forming units (CFU)/fish for red seabream and black seabream, respectively. Among the intestinal flora, Vibrio (ca. 45%) and Pseudomonas (30%) were the most dominant bacteria.The total bacterial counts were 3.1×10⁴ CFU/ml for rearing water, 2.1×10⁷ CFU/g for live diets (rotifer and brine shrimp) and 1.2×10⁴ CFU/g for artificial diets. Among the water bacteria, Pseudomonas (22%) and Moraxella (29%) constituted dominant groups, and in the live diets Pseudomonas (48%) was predominant. The incidence of Vibrio in waters and live diets was 7% and 11%, respectively.     

Growth and Survival of Blackslip Pearl Oyster Larvae Fed Different Densities of Microalgae

This paper reports on an experiment to determine growth and survival of blacklip pearl oyster, Pinctada margaritifera (L.), larvae fed a 1:1 mixture of Isochrysis aff. galbana clone T-ISO and Pavlova salina at six different densities (1, 2, 5, 10, 20 and 30 × 10³ cells ml^-1. Larval growth and survival were assessed every four days over a 20–day period. Exponential and logistic regression models were fitted to the growth and survival responses, respectively. Overall growth of larvae fed 5 × 10³ cells ml^-1 was significantly greater (p > 0.01) than growth of larvae reared at other algal densities. The optimal food ration for maximum larval growth was 20 × 10³ cells ml^-1, which resulted in larvae with antero-posterior shell length of 230 m after 20 days. These larvae were significantly larger (p > 0.05) than those in all other treatments at the end of the experiment. Survival of larvae fed 0, 1 and 2 × 10³ cells ml^-1 was significantly lower than that of larvae in all other treatments at the end of 15 days (p > 0.01). Maximal survival (8%) over the 20 day period was shown by larvae fed 10 × 10³ cells ml^-1, while lower survival was shown by larvae fed 2 × 10³ cells ml^-1 (2%) and 1 × 10³ cells ml^-1 (0%).     

Effects of adrenaline on ionic equilibria in red blood cells of rainbow trout (Salmo gairdneri)

Effects of adrenaline on the equilibrium distributions of Na⁺ , K⁺ , H⁺ , Cl^– , and H₂O across the cell membrane of rainbow trout (Salmo gairdneri) erythrocytes were determinedin vitro, as a function of P CO₂ (1.76–7.77 torr). CO₂-carrying capacity of the blood was also examined. Plasma catecholamine concentrations inunanaesthetized, unrestrained trout were 3.1 nM adrenaline and 1.2 nM noradrenaline. Elevation of the plasma adrenaline concentrationin vitro to 4.6 × 10³ nM resulted in net gains of Na⁺ , Cl^– and H₂O by red cells, a net loss of H⁺ from red cells, and a pronounced red cell swelling. Adrenaline also reduced the CO₂-carrying capacity of trout bloodin vitro. The magnitudes of these effects increased with P_CO2 and, thus, were sensitive to blood HCO₃ ^– concentrations. The distribution of K⁺ between red cells and plasma was unaffected by adrenaline. Adrenergic-mediated ion movements and red cell swelling were sensitive to both propranolol and SITS. These results are consistent with the symport NaCl uptake model for adrenergic-mediated swelling of Baroinet al. (1984). The adrenergic response of fish erythrocytes may function to ameliorate the effects of blood acidoses on O₂-carrying capacity by maintaining red cell pH in the face of a decrease in plasma pH.     

The use of Pseudoalteromonas sp. F15 in larviculture of the Yesso scallop,Patinopecten yessoensis

A 49‐day rearing trial was conducted to investigate the effects of Pseudoalteromonas sp. F15 on growth, survival, digestive and immune‐related enzyme activities in larval and juvenile Yesso scallop, Patinopecten yessoensis. Larvae (Day 2 post‐fertilization) (d2 PF)) were provided with a diet only of microalgae (control) and supplemented with F15 at final concentrations of 1×10⁴ and 1×10⁶ cells/mL, respectively. Results indicated that the specific growth rates and survival rates of umbo larvae (d13 PF), crawling pediveliger larvae (d28 PF) and juveniles (d51 PF) fed the F15 supplementation diets at 10⁴ and/or 10⁶ cells/mL were significantly higher than those fed the diet of microalgae. Larvae and juveniles fed 10⁴ and/or 10⁶ cells/mL F15 supplementation diets showed a significant increase in pepsin, amylase and cellulase activities compared with the control group. The lysozyme, superoxide dismutase and catalase activities of larvae and juveniles fed the F15 supplementation diets at 10⁴ and/or 10⁶ cells/mL significantly increased compared to those fed the diet of microalgae. In addition, F15 protected juveniles against challenge with Vibrio splendidus. These data suggest that F15 can be useful in scallop larviculture.     

低剂量对虾白斑综合征病毒粗提液对斑节对虾体内潜伏期病毒及血细胞的影响

利用含3×103、6×102、2×102copies/mL的对虾白斑综合征病毒(white spot syndromevirus,WSSV)粗提液和PBS液人工注射感染携带病毒量约1×105copies/g的斑节对虾,通过实时定量PCR法、显微镜观察法研究了感染后斑节对虾发病死亡率、肌肉内WSSV含量及总血淋巴细胞数和不同种类血细胞的比例组成变化。结果表明,3种浓度下斑节对虾累积死亡率分别为93.33%±2.89%、56.67%±5.77%和45.00%±5.00%,对照组没有发生死亡。注射3×103copies/mL的浓度组,在注射后30 min时,对虾肌肉内的病毒含量达到最低值(3.54×104copies/g),而后持续上升至48 h时达到最高值(3.12×108copies/g)后再次下降;另两个感染组,在注射后1 h时,肌肉内病毒含量达到最低值(分别为1.11×105、9.54×104copies/g),在感染后6 h时出现一个次高值(分别为1.58×105、1.11×105copies/g),而后又降低,在48 h时达到最高值(分别为1.48×107、5.46×106copies/g)后下降;对照组对虾肌肉内病毒含量没有出现显著变化。不同感染浓度组,斑节对虾总血淋巴细胞数波动幅度和出现峰值的时间不同,特别是注射3×103copies/mL组,对虾总血淋巴细胞数在12和48 h时出现极低值(分别为3.48×106、4.05×106/mL);3个感染组除个别时间点外,对虾总血淋巴细胞数的变化规律与肌肉中WSSV的扩增规律成负相关。4个处理组,半颗粒细胞比例在感染初期呈现明显上升的趋势,后期比例虽有起伏但均维持在较高水平;颗粒细胞和透明细胞比例在感染初期均呈现明显下降的趋势,中期均略有上升,但后期颗粒细胞比例显著低于初期,而透明细胞比例则与初期无显著性差异。     

Experimental infection of Atlantic halibut, Hippoglossus hippoglossus L., yolk-sac larvae with infectious pancreatic necrosis virus: detection of virus by immunohistochemistry and in situ hybridization

Three different concentrations (10⁷, 10⁵ and 10³ TCID₅₀ ml^-1) of infectious pancreatic necrosis virus (IPNV) serotype Sp isolated from Atlantic halibut, Hippoglossus hippoglossus L., were used to bath-challenge Atlantic halibut yolk-sac larvae. The larvae challenged with 10⁷ TCID₅₀ ml^-1 suffered significantly higher cumulative mortality than the other challenged groups and the control group, and affected individuals displayed necrosis of the intestine, liver and kidney. In larvae from the groups challenged with 10⁷ and 10⁵ TCID₅₀ ml^-1, IPNV was detected by immunohistochemistry and in situ RNA/DNA hybridization in the intestine, liver and kidney. In addition, some individuals stained IPNV-positive in the heart and eye/brain region. Detection by in situ hybridization did not appear to be more sensitive than immunohistochemistry. However, background staining was virtually absent in comparison with immunohistochemistry, and the staining seemed to be more distinctly localized to the cytoplasm of infected cells. The results show that farmed halibut yolk-sac larvae can be infected by IPNV immediately after hatching, with resulting high mortality. As the larvae are not immunologically mature at this stage of development, vaccination is not recommended.     

澜沧江源区浮游植物群落特征及其对水质的指示作用

为了探究澜沧江源区水生态现状与变化趋势,在干流囊谦段布置多昌、扎曲大桥及香达3个监测点,支流选择子曲的下拉秀、尕麻和野吉尼玛3个监测点,共计6个监测点位,于2016年7月(夏季)和10月(秋季)对澜沧江源区干流及其支流浮游植物进行了调查,以期为三江源区水生态保护与管理提供科学依据。结果表明:(1)记录浮游植物7门、47种,其中硅藻(21种)和绿藻(14种)为主要成分,分别占总种类数的45%和30%;时空差异明显,夏季较秋季种类丰富,支流较干流种类丰富;优势种以硅藻为主,其中针杆藻(Synedra sp.)为两季度绝对优势种;(2)澜沧江源区浮游植物密度为5.4×10~4～230×10~4个/L,平均密度为79×10~4个/L,硅藻贡献最大;时空差异明显,秋季高于夏季,支流高于干流;(3)浮游植物Shannon-Wiener多样性指数(H)夏季为2.32,秋季为2.72,Pielou均匀度指数(J)夏季为0.73,秋季为0.70。研究显示,澜沧江源区水质介于极贫营养至中营养之间,处于轻度污染至无污染状态,水生态状况整体优良。     

Experimental infection of Atlantic halibut,Hippoglossus hippoglossus L., yolk-sac larvae with infectious pancreatic necrosis virus: detection of virus by immunohistochemistry and in situ hybridization*

Three different concentrations (10⁷, 10⁵ and 10³ TCID₅₀ ml^?1) of infectious pancreatic necrosis virus (IPNV) serotype Sp isolated from Atlantic halibut, Hippoglossus hippoglossus L., were used to bath-challenge Atlantic halibut yolk-sac larvae. The larvae challenged with 10⁷ TCID₅₀ ml^?1 suffered significantly higher cumulative mortality than the other challenged groups and the control group, and affected individuals displayed necrosis of the intestine, liver and kidney. In larvae from the groups challenged with 10⁷ and 10⁵ TCID₅₀ ml^?1, IPNV was detected by immunohistochemistry and in situ RNA/DNA hybridization in the intestine, liver and kidney. In addition, some individuals stained IPNV-positive in the heart and eye/ brain region. Detection by in situ hybridization did not appear to be more sensitive than immunohistochemistry. However, background staining was virtually absent in comparison with immunohistochemistry, and the staining seemed to be more distinctly localized to the cytoplasm of infected cells. The results show that farmed halibut yolk-sac larvae can be infected by IPNV immediately after hatching, with resulting high mortality. As the larvae are not immunologically mature at this stage of development, vaccination is not recommended.