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1.
调查了凡纳滨对虾养殖池塘水体中微囊藻毒素的含量及其与环境因子间的关系,为凡纳滨对虾健康养殖提供理论依据.本实验室采用固相萃取(SPE)和高效液相色谱(HPLC)测定其微囊藻毒素MC-LR的含量;研究了MC-LR浓度与氨氮(NH3-N)、总氮(TN)、总磷(TP)和水温等环境因子间的关系.结果发现其水样检测出微囊藻毒素MC-LR的最高浓度为23.15μg/L,氨氮、TN、TP与MC-LR均呈显著性正相关,氨氮、TN、TP、MC-LR与水温均呈显著性负相关.该实验结果验证了在发病的凡纳滨对虾养殖池塘中检出微囊藻毒素MC-LR的现象,初步推论凡纳滨对虾养殖池塘中微囊藻毒素MC-LR的含量与相关环境因子有关.  相似文献   

2.
夏季高温时,养殖水体水华现象频繁发生,给养殖业带来巨大的损失。常见水生植物释放的活性物质在低浓度下可以起到抑藻作用,对藻类调控具有重要意义。本研究采用实验室静态模拟方法,取养殖池塘暴发蓝藻水华的水体,与沉水植物金鱼藻(Ceratophyllum demersum)及篦齿眼子菜(Potamogeton pectinatus)进行共培养,研究这2种沉水植物对养殖水华水体营养水平、藻类生长、藻类结构及浮游藻类生物多样性的影响。结果显示,金鱼藻和篦齿眼子菜可显著降低水华水体氮、磷等营养水平(P<0.05);金鱼藻和篦齿眼子菜可有效抑制水华蓝藻(Cyanobacteria)生长,尤其对颤藻和微囊藻(Microcystis sp.)效果显著(P<0.05),且篦齿眼子菜对水华蓝藻抑制效果更为显著。实验结束时,篦齿眼子菜培养组藻密度下降93.6%,生物量下降98.9%,叶绿素a含量下降60.5%;金鱼藻培养组藻密度下降72.5%,生物量下降86.8%,叶绿素a含量下降54.3%;金鱼藻和篦齿眼子菜的存在可促进养殖水体浮游藻类生物多样性增加,且金鱼藻提高浮游藻类生物多样性效果更显著。金鱼藻培养组浮游藻类生物多样性升高98.4%,篦齿眼子菜培养组浮游藻类生物多样性升高50.3%。本研究结果可为未来生态养殖提供理论依据和参考。  相似文献   

3.
采用固相萃取(SPE)和高效液相色谱-串联质谱法(HPLC/MS-MS)对湖州某淡水青虾养殖池塘水体中溶解态微囊藻毒素(MC-LR,MC-RR)浓度进行了监测,研究了微囊藻毒素浓度变化及其与总氮(TN)、总磷(TP)、氨氮(NH3-N)、水温、叶绿素a(Chl-a)等水体环境因子之间的关系。结果显示:养殖水体藻毒素浓度在监测期间波动明显,游离的MC-LR的最高浓度达到了102.3 mg/L,MC-RR的最高值为32.6 mg/L,MCLR的浓度要高于相应时段的MC-RR。MC-LR和MC-RR的浓度变化呈显著性正相关。在整个监测周期内TN、TP与MC-LR均呈显著性正相关,NH3-N、TN与水温均呈显著性负相关,TP与MC-RR呈显著性正相关,Chl-a与TP、MCs呈显著性正相关。  相似文献   

4.
浙江诸暨三角帆蚌养殖池塘浮游植物群落结构和理化环境   总被引:1,自引:0,他引:1  
2011年8月29日—9月1日采样分析了浙江省诸暨市枫桥镇10口三角帆蚌(Hyriopsis cumingii)养殖池塘中的浮游植物种类组成、生物量和理化环境因子。结果显示,三角帆蚌养殖池塘内共观察到浮游植物51属(种),优势种为平裂藻、微囊藻、腔球藻和栅藻;浮游植物生物量为0.71~8.01×108cell/L,71%~97%为蓝藻。池塘内的透明度(SD)平均值为33 cm、溶氧(DO)为4~12 mg/L、总氮(TN)为1.933~4.062 mg/L、总磷(TP)为0.154~1.010 mg/L、高锰酸钾指数(CODMn)为6.49~10.06 mg/L,说明三角帆蚌养殖池塘具有DO较高,SD、TN、TP、CODMn和TN/TP较低的特点。RDA分析显示水温是影响池塘中浮游植物常见种类生物量的主要环境因子,说明相近池塘的浮游植物群落接近。鉴于所调查的池塘内TN、TP、CODMn和TN/TP较低,建议适当增加杂食性鱼类放养密度和配合饲料投喂量并降低鸭粪施肥量。  相似文献   

5.
为了解蓝藻水华期间微囊藻毒素在罗非鱼体内的分布及累积传递过程,2008年6~8月采集了高密度蓝藻池塘及太湖网箱内的鱼样及水样,用ELISA法对鱼样和水样进行微囊藻毒素MC-LR含量的检测。结果表明,池塘水体微囊藻毒素MC-LR含量在0.123~0.514μg/L,MC-LR含量随着藻密度的下降而降低,对照组水体MC-LR浓度显著高于实验组MC-LR含量。池塘鱼体肌肉组织微囊藻毒素MC-LR累积含量在1.194~3.615ng/g,肝脏组织微囊藻毒素MC-LR累积含量显著高于肌肉组织。将池塘与网箱罗非鱼转至无微囊藻水体中暂养,跟踪检测MC-LR含量变化,池塘和网箱鱼体肌肉组织微囊藻毒素MC-LR含量均低于人体每日可耐受摄入量,而肝脏组织藻毒素MC-LR含量则分别需要经过10~20d自然生物降解后降低至安全摄入量之下。讨论了微囊藻毒素在鱼体组织分布与食物链中的累积传递。  相似文献   

6.
为了解蓝藻水华期间微囊藻毒素在罗非鱼体内的分布及累积传递过程,2008年6~8月采集了高密度蓝藻池塘及太湖网箱内的鱼样及水样,用ELISA法对鱼样和水样进行微囊藻毒素MC-LR含量的检测.结果表明,池塘水体微囊藻毒素MC-LR含量在0.123~0.514 μg/L,MC-LR含量随着藻密度的下降而降低,对照组水体MC-LR浓度显著高于实验组MC-LR含量.池塘鱼体肌肉组织微囊藻毒素MC-LR累积含量在1.194~3.615ng/g,肝脏组织微囊藻毒素MC-LR累积含量显著高于肌肉组织.将池塘与网箱罗非鱼转至无微囊藻水体中暂养,跟踪检测MC-LR含量变化,池塘和网箱鱼体肌肉组织微囊藻毒素MC-LR含量均低于人体每日可耐受摄入量,而肝脏组织藻毒素MC-LR含量则分别需要经过10~20d自然生物降解后降低至安全摄入量之下.讨论了微囊藻毒素在鱼体组织分布与食物链中的累积传递.  相似文献   

7.
为了解蓝藻水华期间微囊藻毒素在罗非鱼体内的分布及累积传递过程,2008年6月至8月采集了高密度蓝藻池塘及太湖网箱内的鱼样及水样,用ELISA法对鱼样和水样进行微囊藻毒素MC-LR含量的检测。结果表明:池塘水体微囊藻毒素MC-LR含量变化范围在0.123~0.514ug/L间,MC-LR含量随着藻密度的下降而降低,对照组水体MC-LR浓度显著高于实验组MC-LR含量。池塘鱼体肌肉组织微囊藻毒素MC-LR累积含量在1.194~3.615ng/g间,肝脏组织微囊藻毒素MC-LR累积含量显著高于肌肉组织。将池塘与网箱罗非鱼转至无微囊藻水体中暂养,跟踪检测MC-LR含量变化,池塘和网箱鱼体肌肉组织微囊藻毒素MC-LR含量均低于人体每日可耐受摄入量,而肝脏组织藻毒素MC-LR含量则分别需要经过10~20天自然生物降解后降低至安全摄入量之下。并讨论了微囊藻毒素在鱼体内的组织分布与食物链中的累积传递。  相似文献   

8.
郑州郊区精养池塘微囊藻毒素检测分析   总被引:1,自引:0,他引:1  
雷庆铎  马宁  陈志冉 《水利渔业》2007,27(5):72-72,82
选择郑州郊区黄河南岸成片精养池塘5口,在养殖高峰期的8月份和养殖淡季的3月份各取水样1次。8月份藻毒素的检出率为100%,检出质量浓度范围为0.12~0.32μg/L,平均0.21μg/L;3月份5口精养池塘有3口检出藻毒素,检出率为60%,检出质量浓度范围为0.08~0.16μg/L,平均为0.08μg/L。总体上郑州郊区精养池塘的藻毒素含量较低,但应注意养殖高峰季节暴发蓝藻水华和天气突变。  相似文献   

9.
近年来,我国不少地区水质日趋富营养化,藻类水华频繁暴发,危害水产养殖,其中微囊藻是我国池塘养殖中最常见,危害最严重的藻类之一。现就我国微囊藻的控制研究作一介绍。 一、微囊藻水华暴发的机制  相似文献   

10.
南太湖入湖口叶绿素a时空变化及其与环境因子的关系   总被引:2,自引:0,他引:2  
根据2010年1-12月专项监测数据,分析南太湖入湖口水域叶绿素a含量的时空变化特征以及与水温和营养盐等主要环境因子的相关性.研究表明,叶绿素a含量随时间变化明显,夏季最高,秋冬季次之,春季最低;在空间分布上,太湖西南入湖口水域的叶绿素a含量明显高于太湖南部入湖口水域.叶绿素a含量全年平均值为(15.71 ±11.24) μg/L,变化范围在1.50~74.3μg/L.叶绿素a含量与水温、pH、高锰酸盐指数(CODMn)、总磷(TP)、氨氮(NH4+-N)呈极显著正相关,与溶解氧(DO)、总氮(TN)、TN/TP呈极显著负相关.叶绿素a含量变化受多个因子共同影响,水温是叶绿素a含量变化的关键因子.氮磷比平均值为17.8,在藻类生长氮磷比的最佳范围内,易发生蓝藻水华.叶绿素a含量的对数与TP的对数呈极显著正相关,与TN和TN/TP的对数呈极显著负相关.磷是南太湖入湖口水域浮游植物生长的限制因子.  相似文献   

11.
12.
Growth hormone (GH) and reproduction: a review   总被引:5,自引:0,他引:5  
Interaction between growth and reproduction occurs in many vertebrates and is particularly obvious at certain stages of the life cycle in fish. Endocrine interactions between the gonadotropic axis and the somatotropic axis are described, the potential role of GH being emphasised. A comparative analysis of these phenomena in mammals, amphibians and fish, suggests a specific role of GH in the physiology of puberty, gametogenesis and fertility. It also shows the original contribution made by studies on the fish model in this field of investigations.  相似文献   

13.
The environmental processes associated with variability in the catch rates of bigeye tuna in the Atlantic Ocean are largely unexplored. This study used generalized additive models (GAMs) fitted to Taiwanese longline fishery data from 1990 to 2009 and investigated the association between environmental variables and catch rates to identify the processes influencing bigeye tuna distribution in the Atlantic Ocean. The present findings reveal that the year (temporal factor), latitude and longitude (spatial factors), and major regular longline target species of albacore catches are significant for the standardization of bigeye tuna catch rates in the Atlantic Ocean. The standardized catch rates and distribution of bigeye tuna were found to be related to environmental and climatic variation. The model selection processes showed that the selected GAMs explained 70% of the cumulative deviance in the entire Atlantic Ocean. Regarding environmental factors, the depth of the 20 degree isotherm (D20) substantially contributed to the explained deviance; other important factors were sea surface temperature (SST) and sea surface height deviation (SSHD). The potential fishing grounds were observed with SSTs of 22–28°C, a D20 shallower than 150 m and negative SSHDs in the Atlantic Ocean. The higher predicted catch rates were increased in the positive northern tropical Atlantic and negative North Atlantic Oscillation events with a higher SST and shallow D20, suggesting that climatic oscillations affect the population abundance and distribution of bigeye tuna.  相似文献   

14.
Previously, we reported 10 PEGE types of 85 tilapia Streptococcus agalactiae(GBS), which shifted from Streptococcus iniae in China, by using PEGE method. Presently, larger and more representative tilapia GBS were isolated, for the ?rst time in China, to characterize their serotypes and genetic diversities more precisely than had done before. 168 GBS strains were distributed in ?ve provinces of China, in which Guangdong, Guangxi and Hainan were the major ones, holding36.9%(62/168), 37.5%(63/168) and 19.6%(33/168), respectively. Serotypes, Ia, Ib and III, were observed in these strains and the most predominant one was Ia(95.2%), which mainly distributed in Guangdong, Guangxi and Hainan. Ia initially occurred in 2009, it shoot up to 32.1% in 2010,but decreased to 16.1% in 2011 before went up to 45.2% in 2012. Ib sporadically occurred during2007–2011, III onlyoccurred in 2012. 14 different PFGE types, including 4 new types(N, O,P and Q), were observed, in which B, D, F and G were the predominant types, holding 83.9%(141/168) of the total GBS strains. Ia corresponded to 11 PFGE types(A–H, N–P), in which type D predominated(51%). Ib represented 3 genotypes(I, J and Q) and III harbored only 2genotypes(N and F). Type N and Fsynchronously presented in Ia and III. In summary, the genetic diversity of tilapia GBS varied by serotypes and changed with geographical locations and years.Although Iastillpredominated, new rareserotypeIII alreadyoccurred in China.  相似文献   

15.
16.
Protein and amino acid composition of the mantle of juvenile O ctopus vulgaris (Cuvier, 1797) during fasting for 27 days were determined. Average protein content of octopus mantle was of 711.19 ± 46.80 g kg?1 DW, and it decreased with increasing fasting days. The non‐essential amino acids content was higher (486.18 ± 11.08 g kg?1 protein) than essential amino acids (425.82 ± 9.15 g kg?1 protein) at the start of the experiment (unstarved animals). The results suggest that the amino acid profile of the mantle where the most abundant amino acids are Arg, His, Lys, Gly, Leu and Pro could indicate a prolonged fasting condition (>20 days) or poor nutrition of O . vulgaris. This study supports the idea of using mantle for metabolic needs of starved O . vulgaris suggesting that the degradation pathway of amino acids to pyruvate and tricarboxylic acid cycle intermediates was favoured contrary to the degradation pathway of ketogenic amino acids. Special considerations should be taken concerning Thr, Ile, Ser, Ala, Asx (Asp, Asn), Glx (Glu, Gln) (because of their fast intake) and Lys and His (due to their stable contents) during a prolonged period of fasting.  相似文献   

17.
The endemic, anadromous cyprinidChalcalburnus tarichi is the only fish species known to occur in alkaline Lake Van (Eastern Anatolia, Turkey). EightC. tarichi were maintained individually in Lake Van water (17 – 19°C; pH 9.8; 153 mEq·I–1 total alkalinity; 22 total salinity) and tank water samples analyzed for 24 h in 2 to 4 h intervals. At zero time, < 1µM ammonia was present and urea was undetectable in the tank water; at 24 h, total ammonia and urea made up 114±32 and 35±25µM, respectively. Over the experimental period, ammonia-N and urea-N excretion averaged 1041±494 and 607±169moles·kg–1 fish·h–1, respectively. The extent of urea excretion was highly variable between specimens. Uric acid excretion was not detectable.Urea was present at high concentrations in all tissues and plasma (25 – 35moles·g–1·ml–1) of freshly caughtC. tarichi; total ammonia content of the tissues was by a factor of 1.9 (liver) to 3.0 (brain) lower. High arginase activity (2.4±0.2 U·min–1·g–1) was detected in the liver ofC. tarichi but ornithine carbamoylphosphate transferase, a key enzyme of the ornithine-urea-cycle, was absent. Ureagenesis is likely through degradation of arginine and/or uricolysis. High glutamine synthetase activity (11±0.6 U·min–1·g–1) and low ammonia content in brain suggest that, like other teleosts,C. tarichi has an efficient ammonia detoxification in the brain, but in no other tissue.Nitrogenous waste excretion at alkaline pH is discussed. The ability ofC. tarichi to excrete high levels of ammonia at extremely alkaline pH is unique among teleosts studied so far. The mechanism of ammonia excretion under Lake Van conditions remains to be elucidated.  相似文献   

18.
In this experiment, a feeding trial was performed to determine the effects of fructooligosaccharide (FOS) on growth performance, digestive enzyme activity and immune response of Japanese sea bass, Lateolabrax japonicus juveniles (initial weight 38.3 ± 0.5 g), and the fish were examined following feeding with six levels of FOS (0, 0.5, 1, 2, 4 and 6 g/kg) for 28 days. Significant enhancement of weight gain (WG) and specific growth rate (SGR) was found in fish fed 1 g/kg FOS incorporated diets (p < .05), while the feed conversion ratio (FCR) in the 1, 2 g/kg FOS groups reduced significantly compared with the control (p < .05). Besides, the crude lipid in the 4, 6 g/kg FOS groups increased significantly compared with the control (p < .05). On the other hand, the erepsin and lipase activities significantly elevated in intestine of fish fed 2 g/kg FOS (p < .05) and the lysozyme activity in serum of fish fed 2 g/kg FOS were significantly higher than that in the control (p < .05). Moreover, the alkaline phosphatase activities in serum of fish fed 0.5, 1, 2 g/kg FOS were significantly higher than in control (p < .05). Regression analysis showed that the relationships between dietary FOS levels and either SGR, FCR, erepsin or lysozyme activities were best expressed by regression equations, and the optimal inclusion levels are 1.37, 1.80, 3.06, 3.11, 1.93 and 1.80 g/kg for SGR, FCR, erepsin, lipase, lysozyme and total superoxide dismutase activities, respectively. Overall, this study revealed that FOS incorporated diets could beneficial for L. japonicus culture in terms of increasing the growth, digestion and immune activities. Under the present experimental condition, the optimal supplementary level of FOS in the diet of L. japonicus is 1–3 g/kg.  相似文献   

19.
  1. Humanity is facing a biodiversity crisis, with freshwater-associated biodiversity in a particularly dire state. Novel ecosystems created through human use of mineral resources, such as gravel pit lakes, can provide substitute habitats for the conservation of freshwater and riparian biodiversity. Many of these artificial ecosystems are subject to a high intensity of recreational use, however, which may limit their biodiversity potential.
  2. The species richness of several taxa (plants, amphibians, dragonflies, damselflies, waterfowl, and songbirds) was assessed and a range of taxonomic biodiversity metrics were compared between gravel pit lakes managed for recreational fisheries (n = 16) and unmanaged reference lakes (n = 10), controlling for non-fishing-related environmental variation.
  3. The average species richness of all the taxa examined was similar among lakes in both lake types and no substantial differences in species composition were found when examining the pooled species inventory. Similarly, there were no differences between lake types in the presence of rare species and in the Simpson diversity index across all of the taxa assessed.
  4. Variation in species richness among lakes was correlated with woody habitat, lake morphology (surface area and steepness), and land use, but was not correlated with the presence of recreational fisheries. Thus, non-fishing-related environmental variables had stronger effects on local species presence than recreational fisheries management or the presence of recreational anglers.
  5. Collectively, no evidence was found that anglers and recreational fisheries management constrain the development of aquatic and riparian biodiversity in gravel pit lakes in the study region; however, the conservation of species diversity in gravel pit lakes could benefit from an increasing reliance on habitat enhancement activities.
  相似文献   

20.
The aim of this study was to describe two epizootics of high mortalities from infection with Streptococcus agalactiae, occurring in captive rays held in a marine display aquarium in south‐east Queensland, Australia, in 2009 and 2010. Five different species of rays were affected, including mangrove whiprays (Himantura granulata), estuary rays (Dasyatis fluviorum), eastern shovelnose rays (Aptychotrema rostrata), white‐spotted eagle rays (Aetobatus narinari) and blue‐spotted mask rays (Neotrygon kuhlii). This report describes the history of both epizootics including collection, quarantine and husbandry of rays, the disease epizootics, clinico‐pathological features of the disease, antimicrobial therapy, autogenous vaccine production, and laboratory studies including clinical and histopathology, bacteriology, PCR, molecular serotyping and sequencing of the bacterium S. agalactiae.  相似文献   

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