湛江东海岛鲍鱼养殖场水质分析

为了监测湛江东海岛鲍鱼养殖场的水质状况,2011年春季对湛江东海岛九孔鲍养殖场的水质进行采样分析,并应用单项指标评价和富营养化评价等方法,对水质状况进行了评价。结果表明,该养殖场水体采样点的水温为16.0～17.5℃,盐度是22,pH值在7.83～7.90之间,均符合我国第二类海水水质标准。各采样点的溶解氧(DO)和生化需氧量(BOD5)也符合第二类海水水质标准,但化学需氧量(COD)值在14.88～15.36 mg/L之间,与第二类海水水质标准相比严重超标;各采样点的无机氮(DIN)均以NO 3--N为主,DIN值在1.053～1.569 mg/L之间,DIN含量严重超过我国第二类海水水质标准。该养殖场水体属于氮富营养化。     

昌黎县海湾扇贝养殖海域水质调查与评价

根据2018年9月10日对昌黎县海湾扇贝养殖海域的水质调查数据,分析了该海域水体基本理化因子,并采取营养状态质量指数评价法(NQI)、营养状态指数法(E)、有机污染指数评价法(A)及内梅罗环境质量综合评价指数法(P)对水质进行综合评价。结果表明:昌黎县海湾扇贝养殖海域各站位的水温、盐度、pH、DO、COD和DIP含量均符合海湾扇贝养殖水质标准,但是DIN含量严重超标。评价结果显示昌黎县海湾扇贝养殖海域已受到有机污染且水体呈现富营养化,养殖区内比养殖区外情况更为严重,其中N7站位最甚。DIN为该海域主要污染因子。     

海陵湾口海水水质的综合分析与评价

根据2015—2016年4个航次的调查数据,对海陵湾口海水温度、盐度、p H、溶解氧(DO)、化学需氧量(COD)、无机氮(DIN)、无机磷(DIP)、叶绿素a(Chl-a)、石油类、硫化物和重金属质量浓度等16项水质指标进行分析,并通过综合污染评价指数(P)、富营养状态(E)和质量评价指数(NQI)对该区域渔业环境质量进行综合评价。结果显示,对海陵湾海域污染贡献率最高的因子依次是石油类、DIN、COD和DO,不同季节海水受污染程度和主要污染物水平存在显著差异(P0.05);春季海水中DIN污染贡献率最高(0.27~0.69 mg·L~(–1)),仅达到国家四类海水标准;夏季水质清洁,达到国家二类海水标准,但DO质量浓度(4.69~5.93 mg·L~(–1))显著低于其他三季;秋冬两季海水均受到一定程度的石油污染,海水中石油类质量浓度分别达0.069 mg·L~(–1)和0.143 mg·L~(–1),均超过国家二类海水标准限量值,综合评价结果为轻度污染;冬季海水中COD值(3.67 mg·L~(–1))和Chl-a质量浓度(13.07 mg·m–3)均显著高于其他季节,11个调查站位(90%以上)NQI值大于3,水质呈现明显的富营养化状态。     

不同氨氮和溶解氧条件下循环海水养殖系统生物滤池对氨氮、化学耗氧量及颗粒悬浮物的处理效果

为了建立优化的循环海水养殖系统,采用水质国标检测方法分析了珊瑚石生物滤池在不同氨氮和溶解氧(DO)负荷实验条件下对养殖废水中氨氮、化学耗氧量(COD)及颗粒悬浮物(SS)的处理效果。结果显示,进水氨氮浓度对出水氨氮(正相关)、COD(正相关)均有极显著的影响(P0.01),对SS处理效果影响不显著。当进水氨氮浓度为0.45~0.65 mg/L时,滤池对水体处理效果最优(氨氮平均清除率为82.1%±3.3%;COD平均清除率为7.1%±1.5%;SS平均清除率为5.8%±1.6%)。DO浓度对水体氨氮(负相关)和COD(负相关)处理效果的影响显著(P0.05),对SS处理效果影响不显著。DO浓度为5.0~7.0 mg/L时,水体处理效果最优(氨氮平均清除率为78.7%±3.5%;COD平均清除率为23.0%±5.3%;SS平均清除率为7.1%±2.0%)。因此,本实验环境下的循环海水养殖系统珊瑚石生物滤池在氨氮浓度为0.45~0.65 mg/L,DO浓度为5.0~7.0 mg/L时,对水体中的氨氮、COD、SS的综合处理效果最优。     

辽宁盘锦增养殖区水质调查与评价

根据2017年的实测数据对辽宁盘锦海水增养殖区海域的水质状况进行分析,结果表明,所有监测站位中10月份DO含量最高,5月份次之,7月和8月最低,所有站位在这4次监测中有25%出现超标现象。COD含量在夏季出现最大值,8月和10月份所有站位COD均超出第一类海水水质标准,其余月份有部分站位也超出了第一类海水水质标准。除10月份的7号站位外,各监测月份盘锦增养殖区DIN均受到污染,污染程度较重,大部分站位超出了第二类海水水质标准。8月份DIP污染物最高,10月份次之,但均超出第一类海水水质标准,7月份有个别站位超出第一类海水水质标准,5月份所有站位水质状况良好,均未超出第一类海水水质标准。从季节变化分析可以发现,DO变化特征为秋季>春季>夏季,COD存在夏季>秋季>春季的变化特征,夏季DIN含量明显高于其它季节。     

杂交青虾“太湖1号”繁育池塘水质监测及分析

2011年6月9日-7月7日,对江苏扬州地区三家杂交青虾"太湖1号"繁苗单位3口繁育池池水的pH、DO、氨氮、TN、TP和COD的变化进行了监测。结果表明:(1)繁育池水pH的变化范围7.8～8.9,均值8.4;DO的变化范围4.5～6.5mg/L,均值5.3mg/L;氨氮的变化范围:0.172～0.635mg/L,均值0.398mg/L;TN的变化范围:0.938～2.340mg/L,均值1.584mg/L;TP的变化范围0.049～0.235mg/L,均值0.127mg/L;COD的变化范围5.00～16.35mg/L,均值10.90mg/L。(2)3口池塘水质的pH、DO基本符合养殖规范要求;氨氮値高于渔业水质标准及青虾养殖水质要求;COD总体偏高;但Ⅰ、Ⅲ号池仍取得了较好的生产实绩。在监测后期,Ⅰ、Ⅲ号池的TN/TP値12.47∶1～15.37∶1,高于Ⅱ号池的7.82∶1～10.25∶1,Ⅰ、Ⅲ号池的浮游植物的生长状态比较符合幼虾的生长需要。     

湛江港沙湾对虾养殖场虾池水质状况分析

2002年4～7月,对湛江港沙湾对虾养殖场虾池的水质及对虾的生长情况进行连续监测,应用单项指标评价、富营养化评价等方法,对该养殖场的水质状况进行了评价和营养分级。结果表明,该养殖场的水质呈高N低P状态,水温、DO和大部分池的pH、DRP符合第二类海水水质标准,DIN超标,超标率达70%,该养殖场目前处于P中等限制潜在性富营养水平阶段。     

闭合循环水产养殖-植物水栽培综合生产系统的工艺设计及运行效果

闭合循环水产养殖-植物水栽培综合生产系统主要由鱼类养殖池、蔬菜和花卉水培渠、循环水处理系统构成,是一种新型"养殖-种植-水质净化"生产模式。在上海市青浦区的实践表明:①单位水体红罗非鱼(Tilapiamossambica(♀)×Tilapianilotica(♂))和暗纹东方(Fuguobscurus)的产量分别达到58kg·m-3和12.28kg·m-3,养殖期间,氨氮浓度<1.5mg·L-1,亚硝氮浓度<0.8mg·L-1,DO>5.0mg·L-1;②水栽培蔬菜生长良好,对氨氮、亚硝氮、硝氮、总氮、磷酸盐和COD的最大去除率分别为57.46%、51.72%、3.7%、10.67%、9.72%和21.78%,水培蔬菜渠进水和出水的平均N/P分别为6.60∶1和6.53∶1;③生物过滤器对流经水体的NH 4 N、NO-2 N、COD一次性去除率分别为44.79%、20.31%、20.10%;④泡沫分离—臭氧消毒装置对养殖水体中异养细菌的去除率为93.58%,NH 4 N、NO-2 N的去除率为39.00%、38.10%,能明显提高水体中的pH和DO。     

湛江市东海岛对虾养殖池水质污染状况分析

本文对湛江市东海岛对虾养殖场虾池水质的pH值、溶解氧（DO）、氨氮、化学需氧量（COD）和无机磷（DIP）进行连续监测。实验结果表明：对虾养殖池水质pH值为7．8—9．0,溶解氧浓度为6．23—10．34mg／L,氨氮浓度为0．038—0．112mg／L,无机磷浓度为0．017～0．042mg／L,化学需氧量浓度为8．23—14．57mg／L。应用单项指标评价法和综合指数法进行评价,其化学需氧量超出富营养化阈值,需要对水体进行增氧等措施,降低水体有机物负荷等,其它指标基本适合对虾养殖的要求．     

江苏泗阳青虾养殖中期水体的理化环境和浮游植物

2018年7月12日采样分析江苏省泗阳县9处青虾( Macrobrachium nipponense )养殖中期水体的理化环境、浮游植物种类组成和密度,并比较不同养殖模式对养殖环境的影响。结果显示:青虾养殖水体中,溶氧(DO)>8.44 mg/L、pH 7.91~9.26、总氮(TN)1.030~1.571 mg/L、总磷(TP)0.174~0.421 mg/L、高锰酸钾指数(COD Mn )4.39~8.16mg/L,说明青虾养殖水体具有DO和pH较高,N、P及有机质较低的特点。养殖水体内共观察到浮游植物64属/种,以蓝藻和绿藻为主,浮游植物多样性指数较高,群落结构较稳定;浮游植物密度为0.06×10^8~3.06×10^8个/L。RDA分析显示,水温、亚硝酸盐氮(NO2^--N)和COD Mn 是影响青虾养殖水体中优势浮游植物密度的主要环境因子。不同混养种类对青虾养殖水体理化指标和浮游植物具有一定的影响,但管理模式对环境因子的影响更显著。鉴于所调查的青虾养殖水体内pH和Ca 2+质量浓度低于青虾生长最适值及TP和COD Mn质量浓度升高会增加蓝藻水华暴发的风险,建议适当施加生石灰来提高养殖水体中的pH和Ca 2+质量浓度,并通过建立构建生态沟渠、生态塘等生态工程化设施控制养殖水体中TP和COD Mn的增加。     

Rare serotype occurrence and PFGE genotypic diversity of Streptococcus agalactiae isolated from tilapia in China

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.     

Growth hormone (GH) and reproduction: a review

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.     

Purification and partial characterization of GtHs (cfLH and cfFSH) from Indian walking catfish (Clarias batrachus) (L.) and development of a homologous ELISA for cfLH

Two gonadotropins (GtH; Qa and Qb) were purified by gel filtration and ion exchange chromatography from the pituitaries of Indian walking catfish (Clarias batrachus). The presence of GtH during purification was assessed by in vitro oocyte maturation and in vivo steroidogenic activity, and their identities were determined by elution profiles, molecular weight, biological activities and yield. The molecular weights of Qa and Qb were 37 and 42 kDa, respectively, and composed of distinct subunits (Qa: 20 and 14 kDa and Qb: 26 and 18 kDa). Polyclonal antibodies raised against Qa immunostained Qa, Qb and pituitary GtH cells. A competitive Qa‐ELISA was developed whose sensitivity was 6.25 ng mL^?1 (1.25 ng well^?1) with intra‐ (3.5%) and inter‐ (12.4%) assay coefficients of variation. Displacement curves parallel to the standard were obtained with plasma and pituitary extracts of catfish, Qb and carp GtHII. The assay was validated by measuring the plasma Qa levels after LHRH treatment and in relation to ovarian growth in the female catfish during different reproductive phases. Based on the results, Qa and Qb corresponded to fish LH and FSH respectively. The findings will increase the knowledge of the mechanisms controlling fish reproduction and identification of sensitive phases in fish in captivity for hormonal manipulation.     

Controlled infection of Poecilia reticulata Peters (guppy) with Tetrahymena by immersion and intraperitoneal injection

Tetrahymena is a protozoan parasite, which infects guppy, Poecilia reticulata Peters, and causes substantial economical losses in commercial farms worldwide. Studies of guppy infected by Tetrahymena require standardized infection protocols. The LD50 for Tetrahymena infection of guppies by intraperitoneal (IP) injection was calibrated, and the level obtained was 946 parasites per fish. Guppy infection with Tetrahymena by immersion, imitating the natural route of infection via the integument, was studied under normal or stress conditions. Exposure to cold and netting (CNI) and to cold only (CI) followed by immersion exposure to 10 000 Tetrahymena per mL resulted in 22.5% and 19.2% mortality, respectively, as compared to 14.2% and 10% in groups that were netted only (NI) or non‐stressed (I). Histopathology revealed that immersion infection resulted in a systemic infection. Lysozyme levels, measured 3 weeks after infection, were significantly higher in the CNI group (288 μg per mg protein) compared with CI‐, NI‐ and I‐treated groups (94.5, 64 and 62.3 μg mg^?1, respectively). There was no evident parasite immobilization activity in body homogenates, suggesting no development of acquired immunity. Re‐infection by IP injection revealed no increase in protection in any of the treatment groups, mortality range of 56.3–75%, higher than in the non‐exposed control (40.6% mortality).     

Imported ornamental fish are colonized with antibiotic‐resistant bacteria

There has been growing concern about the overuse of antibiotics in the ornamental fish industry and its possible effect on the increasing drug resistance in both commensal and pathogenic organisms in these fish. The aim of this study was to carry out an assessment of the diversity of bacteria, including pathogens, in ornamental fish species imported into North America and to assess their antibiotic resistance. Kidney samples were collected from 32 freshwater ornamental fish of various species, which arrived to an importing facility in Portland, Oregon from Colombia, Singapore and Florida. Sixty‐four unique bacterial colonies were isolated and identified by PCR using bacterial 16S primers and DNA sequencing. Multiple isolates were identified as bacteria with potential to cause disease in both fish and humans. The antibiotic resistance profile of each isolate was performed for nine different antibiotics. Among them, cefotaxime (16% resistance among isolates) was the antibiotic associated with more activity, while the least active was tetracycline (77% resistant). Knowing information about the diversity of bacteria in imported ornamental fish, as well as the resistance profiles for the bacteria will be useful in more effectively treating clinical infected fish, and also potential zoonoses in the future.     

Effect of iodophor disinfection of non‐hardened Salmo trutta eggs on their bacterial and fungus load

This study investigated the efficiency of iodophor disinfection (135 ppm active iodine for 15–30 min) of non‐hardened Salmo trutta eggs against different groups of bacteria and against fungus. Egg samples were taken from non‐disinfected and from disinfected eggs, microorganisms were cultured on specific nutrient media and their mass was measured by turbidimetric methods. Bacteria and fungus mass of non‐hardened eggs could be reduced but not eliminated by iodophor disinfection with 135 ppm active iodine for 15 min. The extent of reduction was 47–65% (Experiment 1). The efficiency of disinfection increased with disinfection time as the reduction in bacteria and fungus mass was 40–55% after 15 min and 58–74% after 30 min (Experiment 2). Disinfection efficiency of iodophor solution diluted in water (reduction 49–57%) and of iodophor solution diluted in sodium chloride solution iso‐osmolar to the oocytes (reduction 52–61%) was similar (Experiment 3). The reduction in bacteria and fungus mass was persistent as it was 39–72% lower in embryos deriving from disinfected eggs than in embryos deriving from non‐disinfected ones (Experiment 4). In conclusion, the tested disinfection method is inadequate to eliminate pathogens completely but it could positively influence immune defence of eggs and embryos.     

Nitrogenous waste excretion and accumulation of urea and ammonia inChalcalburnus tarichi (Cyprinidae), endemic to the extremely alkaline Lake Van (Eastern Turkey)

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.     

Influence of the antibacterial herbs, Solanum trilobatum, Andrographis paniculata and Psoralea corylifolia on the survival, growth and bacterial load of Penaeus monodon post larvae

The indiscriminate use of antibiotics and chemicals in shrimp hatcheries has led to biomagnification and that in turn could lead to rejection of a whole consignment. The application of the bioencapsulation technique as a tool for curative treatment in shrimp larvae was investigated. Herbs having antibacterial properties such as Solanum trilobatum, Andrographis paniculata and Psoralea corylifolia (methanolic extracts) were bioencapsulated in Artemia and fed to Penaeus monodon post larvae PL 1–25. The post larvae were reared in a medium inoculated with pathogenic bacteria such as Pseudomonas aeruginosa, Staphylococcus aureus, Salmonella typhi and Vibrio sp. Post larvae reared in the non-inoculated water and fed with non-enriched Artemia exhibited 90% survival, highest specific growth rate (12.43%) and reduced bacterial load. P. monodon reared in the bacterial inoculated water and fed with the non-enriched Artemia exhibited the lowest survival (10–30%), specific growth rate (8.42–9.1%) and increased bacterial load (2.86 × 10³ to 3.76 × 10⁵ cfu/g). The methanolic extracts of the herbs helped to increase survival and specific growth rate and reduced bacterial load in the P. monodon culture system. Among the three herbal extracts, P. corylifolia enriched Artemia fed post larvae showed the tendency to higher survival (>50%), growth rate (11.5 averaged) and low bacterial load (1.12 × 10⁵ cfu/g). This revised version was published online in August 2006 with corrections to the Cover Date.