内蒙古典型湖泊夏季浮游植物群落特征及与环境变量的关系

2011年8月对内蒙古岱海、乌梁素海和呼伦湖3个典型湖泊的浮游植物群落结构及水环境状况进行了调查.结果表明,3个湖泊共采集到浮游植物92种,隶属于6门、24科、47属,未采集到黄藻门和金藻门种类.岱海、乌梁素海和呼伦湖分别采集到浮游植物19种、55种和55种.岱海优势种为绿藻中的卵囊藻(Oocystis sp.),占浮游植物总密度的73％;乌梁素海和呼伦湖的优势种群均为蓝藻,但优势种不同,乌梁素海的优势种依次为颤藻(Oscillatoria sp.)、假鱼腥藻(Pseudanabaena sp.)和阿氏项圈藻(Anabaenopsis arnolodii),三者占到浮游植物总密度的76％;呼伦湖的优势种依次为点状平裂藻(Merismopedia minima)、螺旋鱼腥藻(Anabaena variabilis)和柔细束丝藻(Aphanizomenon issatschenkoi),三者占到浮游植物总密度的53％,反映出浮游植物群落结构之间的差异.3个湖泊均已达到富营养水平,部分指标超过Ⅴ类水标准.典范对应分析(canonical correspondence analysis,CCA)表明,Cd和CODMn是影响夏季岱海浮游植物群落演替的重要因子,TP和BOD5是乌梁素海的重要因子,浊度、DO、TN和pH等因子对呼伦湖的影响作用较大,其中浊度的影响作用最大.     

冰封期乌梁素海浮游植物生态位和种间联结性分析

为了解乌梁素海冰封期浮游植物群落结构和生态位特征，于2018年和2019年冬季（1月）进行浮游植物采样调查。根据乌梁素海污染源分布、水文及环境特征，在湖泊入水口（N1~N6）、湖泊中部（N7~N14）和湖泊出水口（N15、N16）选取了16个典型样点，进行浮游植物和水样采集；运用改进的Levins公式和Petraitis指数测定浮游植物优势种的生态位宽度和生态位重叠度。结果表明，2018年和2019年冰封期共鉴定出浮游植物优势种2门6种和6门8种，伪鱼腥藻是2018年的绝对优势种，2019年的绝对优势种为蓝隐藻和旋转囊裸藻。2018年冰封期优势种生态位宽度为0.0711~0.5971，宽度最大的为球衣藻，其次是绿柄球藻和衣藻；2019年冰封期优势种生态位宽度为0.1265~0.5455，宽度最大的为绿柄球藻，其次是具尾逗隐藻和蓝隐藻。2018 年和2019年乌梁素海冰封期各优势种的生态位重叠值分别为0.0078~0.7967 和0.0448~0.9248，整体上重叠值小；2018年冰封期浮游植物优势种绿藻门的衣藻与球衣藻的重叠值最高，2019年隐藻门的具尾逗隐藻与蓝隐藻的重叠值最高。生态位重叠度和生态响应速率显示，2018年乌梁素海冰封期浮游植物群落整体上呈发展趋势，而2019年呈衰退趋势。方差比率法分析显示，优势种整体呈正关联；卡方检验发现，各优势种间的联结性均不显著，大多数藻类种间为负关联，少数为正关联。     

黄河一级支流泽曲河春秋季浮游植物群落结构及多样性评价

于2012年春季(4月)和秋季(9月)对黄河一级支流泽曲河的浮游植物群落结构进行了调查,并应用多样性指数H、均匀度指数J、丰富度指数d,对泽曲河进行了多样性评价。结果显示:浮游植物共4门52种(属),以硅藻门最多,37种(属),占71.2%,其次是蓝藻门9种(属),占17.3%,绿藻门5种(属),占9.6%,裸藻门1属,占1.9%。浮游植物优势种为普通等片藻(Diatoma vulgare)、尖针杆藻(Synedra acus)、曲壳藻(Achnanthes sp.)、舟形藻(Navicula sp.)、桥弯藻(Cymbella sp.)、脆杆藻(Fragilaria sp.)、异极藻(Gomphonem sp.)、小环藻(Cyclotella sp.)、小颤藻(Oscillatoria tenuis)、席藻(Phormidium sp.)和小球藻(Chlorella sp.)11种(属),其中硅藻门8种(属),占优势种类的72.7%。浮游植物平均数量23.08×104 L-1,平均生物量0.088 9mg/L,硅藻数量和生物量分别占总数量的92.3%和总生物量的98.8%,为优势种群。Shannon-Wiener指数平均值2.56,Pielou指数平均值0.79,Marggalef指数平均值0.75。结合浮游植物各项评价指标,得出泽曲河浮游植物群落结构比较稳定,种类分布较为均匀,水体属贫营养型。通过生物多样性指数法对水质进行评价,得出该河段水质属轻度污染。     

基于形态学和高通量测序的海水池塘生态养殖系统中浮游植物多样性比较

利用形态学鉴定方法结合高通量测序技术,对2018年12月海水池塘生态养殖系统中浮游植物群落组成及多样性进行研究,结果显示,2种方法共鉴定浮游植物8个门,绿藻门(Chlorophyta)和隐藻门(Cryptophyta)为主要优势类群.共鉴定浮游植物39个属,仅有5个属,包括裸藻属(Eutreptiella)、颤藻属(O...     

海河干流浮游植物群落及其与环境因子的典范对应分析

2009—2013年选取春末、夏中、秋初3个季节对海河干流浮游植物群落进行了调查,共检出浮游植物8门92属181种,浮游植物主要由绿藻、蓝藻和硅藻组成。主要优势种为:绿藻门的四尾栅藻、小球藻、卵囊藻、月牙藻、卡德藻;蓝藻门的微囊藻、胶鞘藻、螺旋藻、颤藻、蓝纤维藻;硅藻门的小环藻、菱形藻、舟形藻;隐藻门的啮蚀隐藻、卵形隐藻。运用典范对应分析研究该水域各站点主要浮游植物与6个环境因子之间的相互关系,综合分析5年研究结果,总氮、总磷和pH值是影响海河干流浮游植物物种分布的重要因素。     

淡水浮游藻类与鱼体异味关系的初步研究

通过在北京市通州区，昌豆区和海淀区几家渔场采集浮游藻类定量并结合对相应池塘养殖鱼类口感的品尝，初步筛选出以下十个属的种类与养殖鱼体异味有关：篮球藻（Chroococcus)，蓝纤维藻（Dactylococcopsis),颤藻（Oscillatoria)，鱼腥藻（Anabaena)，席藻（Phormidium)，颗粒直链硅藻（Mgranulata)，针杆藻（Synedra)，舟形藻（Navicula)，菱形藻（Nitzschia)和栅藻（Scenedesmus)。     

澜沧江囊谦段夏秋季浮游植物群落结构初步研究

2011年夏季(6月)和秋季(9月)对澜沧江囊谦段的浮游植物进行初步研究。结果表明,澜沧江囊谦段浮游植物共计4门、57种(属);其中,硅藻门种类最多,为33种(属),占总种类数的57.9%;其次是绿藻门,为13种(属),占22.8%,蓝藻门10种(属),占17.5%,甲藻门仅检到1种,占1.8%。夏秋两季澜沧江囊谦段均以喜低温的硅藻为主,绿藻、蓝藻种类秋季多于夏季,甲藻仅在夏季出现。浮游植物优势种以硅藻为主,占75.0%,种类有尖针杆藻(Synedra acus)、普通等片藻(Diatoma vulgare)、舟形藻(Navicula sp.)、桥弯藻(Cymbella sp.)、曲壳藻(Achnanthes sp.)、异极藻(Gomphonem sp.)、颤藻(Oscillatoria sp.)和席藻(Phormidium sp.)。浮游植物数量为13.26×104～375.59×104个/L,平均数量99.36×104个/L;生物量为0.0445～1.9972mg/L,平均0.4915mg/L。浮游植物数量和生物量均以硅藻最高,分别占总数量的61.2%和总生物量的71.3%。分析显示,各采样点浮游植物多样性指数、均匀度指数较高,均值分别为2.24、0.48;表明该河段浮游植物群落比较稳定,种类分布较为均匀,体现了贫营养型河流的特征,水域环境良好。     

新疆大泉沟水库浮游植物群落特征及其与环境因子的关系

为了探究大泉沟水库浮游植物群落结构的动态变化特征及综合水质状况,为库区水资源保护和渔业可持续发展提供参考依据,于2015年10月(枯水期)、2016年4月(丰水期)和7月(平水期),对库区内4个采样点进行了浮游植物群落与水质调查。结果表明,本次调查共鉴定出浮游植物8门161种,其中绿藻67种、硅藻48种、蓝藻26种、裸藻6种、隐藻6种、黄藻6种、金藻1种、甲藻1种,浮游植物群落结构组成属于绿藻-硅藻型;浮游植物主要优势种为小球藻(Chlorella vulgaris)、尖针杆藻(Synedra acus)、拟气球藻(Botrydiopsis intercedens)、四尾栅藻(Scenedesmus quadricauda)、细小平裂藻(Merismopedia minima)等;浮游植物密度为0.86×106~5.54×106个/L、平均值为2.13×106个/L;浮游植物的Shannon-Wiener指数(H)、Margalef指数(Dm)及Pielou均匀度指数(J)变化范围分别为1.97~2.56、1.83~3.01和0.68~0.77。研究显示,大泉沟水库目前处于中污染状态;相关分析表明,水温、总磷、透明度和溶解氧是大泉沟水库浮游植物群落结构变化的主要影响因子,大泉沟水库属中营养至中度富营养水库。     

重盐碱地南美白对虾池塘浮游植物的研究

于2007年6月至9月对利津县陈庄重盐碱地南美白对虾养殖池塘浮游植物的种类组成和生物量进行了研究。共采集水样48个。结果表明,利津重盐碱地养殖池塘浮游植物主要是淡水普生种类,一些是典型的盐水种。浮游植物的优势种为小色球藻、小席藻、针晶兰纤维藻、微小平列藻、铜绿微囊藻、类颤藻鱼腥藻;绿藻门的尖细栅藻、卵形衣藻、湖生卵囊藻和普通小球藻;硅藻门的星肋小环藻、近缘针杆藻;金藻门的卵形单鞭金藻;裸藻门的绿色裸藻;隐藻门的卵形隐藻、啮蚀隐藻和尖尾兰隐藻等。浮游植物的平均密度为6.98×107L-1,变化范围在0.05×107~17.4×107L-1之间;平均重量为51.7 mg/L,变化范围在0.23~207.72mg/L之间。     

西藏色林错-普若岗日国家公园潜在建设区夏季浮游植物群落生态特征

为了探究色林错-普若岗日国家公园潜在建设区夏季浮游植物群落及优势种生态特征,于2015年和2016年8月对浮游植物群落进行了调查分析,并运用生态位宽度、生态位重叠及生态响应速率等方法测定优势种的生态位量度。结果表明：（1）色林错-普若岗日国家公园潜在建设区共鉴定出浮游植物127种,隶属于3门5纲11目18科35属,其中优势种5种,隶属2门5属,优势种丰度和优势度在不同区域均有差异;（2）泉生菱形藻（Nitzschia fonticola）生态位宽度最大,嗜盐舟形藻（Navicula halophila）生态位宽度最小;（3）浮游植物优势种生态位重叠程度不高,种间竞争弱,群落结构较为稳定;（4）浮游植物优势种呈发展或衰退趋势是不同浮游植物优势种间竞争的必然结果。本研究结果为色-普国家公园潜在建设区浮游植物多样性积累基础数据,为探讨生态位分化理论下的种间关系、资源利用及生态适应机制提供参考。     

Protein and amino acid composition from the mantle of juvenile O ctopus vulgaris exposed to prolonged starvation

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.     

美人鱼发光杆菌对凡纳滨对虾非特异性 免疫功能及抗病力的影响

在基础饲料中分别添加0.1%和1%美人鱼发光杆菌灭活菌、0.1%美人鱼发光杆菌活菌配制成3种免疫实验饲料,以基础饲料为空白对照组饲料,每组设3个平行样。对个体质量为(4.83±0.36)g的凡纳滨对虾进行为期20 d的饲养实验,分别在0、5、10、15和20d进行取样,以血清中的酚氧化酶(PO)、酸性磷酸酶(ACP)、碱性磷酸酶(AKP)、超氧化物歧化酶(SOD)和溶菌酶(UL)活性为免疫指标,探讨了美人鱼发光杆菌作为免疫制剂对凡纳滨对虾非特异性免疫效应的影响;在投喂免疫饲料后的第22天,按0.004 2 kg/kg体重的剂量,直接投喂对虾白斑综合征病毒(WSSV)病料,并记录累积死亡率。结果表明,美人鱼发光杆菌免疫实验组对凡纳滨对虾血清中PO、ACP、AKP、UL和SOD活性影响明显高于对照组,并且在饲料中添加美人鱼发光杆菌后,明显提高了对虾抵御WSSV感染的能力。其中0.1%美人鱼发光杆菌活菌实验组的抗病毒感染能力最强,WSSV感染14d内累计死亡率为63.3%±5.8%;而对照组为96.7%±3.3%。研究表明,美人鱼发光杆菌添加在对虾饲料中能提高凡纳滨对虾非特异性免疫水平,增强抵抗疾病的能力,将其作为对虾免疫增强剂具有良好的应用前景。     

Effects of Spirulina platensis as a feed additive on growth and coloration of blue dolphin cichlids (Cyrtocara moorii Boulunger, 1902)

This study was carried out to investigate the effects of replacing fish meal with dietary Spirulina as a feed supplement on the growth performance and coloration of blue dolphin cichlids (Cyrtocara moorii). Five isonitrogenous (47% crude protein) and isocaloric (17.36 kJ/g digestible energy) diets were for formulated to replace FM with 0, 5, 10, 15 and 20% Spirulina (designated as Control, SP5, SP10, SP15 and SP20 respectively) and fed to the fish (initial body weight, 3.15 ± 0.01 g). Fish were randomly distributed into fifteen 120 L aquariums (26.5 ± 1.00°C), 15 fish per aquarium. The diets were tested in triplicate for 12 weeks. Experimental groups were fed twice daily (09:00 and 17:00) by hand to satiation. At the end of the feeding trial, significantly (p < 0.05) higher weight gain (WG), specific growth rate (SGR), protein efficiency ratio (PER) and lower feed conversion ratio (FCR) were observed in fish fed the SP10 diet when compared to the SP20 diet. There was no significant difference in these parameters between the other groups. The skin coloration of blue dolphin cichlid fed a diet containing Spirulina meal was enhanced. The best coloration was observed in the SP15 group. These impressions were objectively validated by chemical determinations of carotenoids extracted from fish skins and passed statistical tests of significance. The study findings show that Spirulina meal does not diminish growth rates except at very high levels.     

Sea bream culture in Egypt; status, constraints and potential

Marine fish farming in Egypt began in 1976 with the culture of gilthead sea bream, (Sparus aurata) as this fish was notably adaptable to brackish and marine pond conditions. Today, marine fish and shrimp farms amount to about 19,000 ha, out of which 42% is already in production while the rest, i.e., 58% is still under construction. In 1997, cultured gilthead sea bream production of 2,250 tons made up 3% of the 75,000 tons total aquaculture catch. In polyculture, usually with the grey mullet and sea bass, gilthead sea bream contributed 440 kg ha^–1 to the total yield of 1,700 kg ha^–1 (26%) over a period of 16 months. For the same period, the yield of monoculture ponds averaged 100 kg ha^–1, while in marine cages, yields ranged from 4–10 kg m³. In 1996–1997, fry of 0.25–1 g and fingerlings 1–10 g with a total of 3 million, were collected from the wild and 1 million fry were produced in the three marine hatcheries out of the four existing ones. The development of sea bream culture in Egypt is now severely inhibited by the shortage of seeds and adequate feeds. Exports of both sea bream and sea bass, during 1994–1996 averaged 1,300 tons per year.     

Dietary thiamin and pyridoxine requirements of fingerling Indian major carp,Cirrhinus mrigala (Hamilton)

Two experiments were conducted to quantify the dietary thiamin (experiment I) and pyridoxine (experiment II) requirements of fingerling Cirrhinus mrigala for 16 weeks. In experiment I, dietary thiamin requirement was determined by feeding seven casein–gelatin‐based diets (400 g kg^?1 CP; 18.69 kJ g^?1 GE) with graded levels of thiamin (0, 0.5, 1, 2, 4, 8 and 16 mg kg^?1 diet) to triplicate groups of fish (6.15 ± 0.37 cm; 1.89 ± 0.12 g). Fish fed diet with 2 mg kg^?1 thiamin had highest specific growth rate (SGR), protein retention (PR), RNA/DNA ratio, haemoglobin (Hb), haematocrit (Hct), RBCs and best feed conversion ratio (FCR). However, highest liver thiamin concentration was recorded in fish fed 4 mg thiamin kg^?1 diet. Broken‐line analysis of SGR, PR and liver thiamin concentrations exhibited the thiamin requirement in the range of 1.79–3.34 mg kg^?1 diet (0.096–0.179 μg thiamin kJ^?1 gross energy). In experiment II, six casein–gelatin‐based diets (400 g kg^?1 CP; 18.69 kJ g^?1 GE) containing graded levels of pyridoxine (0, 2, 4, 6, 8 and 10 mg kg^?1 diet) were fed to triplicate groups of fish (6.35 ± 0.37 cm; 1.97 ± 0.12 g). Fish fed diet containing 6 mg kg^?1 pyridoxine showed best SGR, FCR, PR, RNA/DNA ratio, Hb, Hct and RBCs, whereas maximum liver pyridoxine concentration was recorded in fish fed 8 mg kg^?1 dietary pyridoxine. Broken‐line analysis of SGR, PR and liver pyridoxine concentrations reflected the pyridoxine requirement from 5.63 to 8.61 mg kg^?1 diet. Data generated during this study would be useful in formulating thiamin‐ and pyridoxine‐balanced feeds for the intensive culture of this fish.     

A Minchinia mercenariae‐like parasite infects cockles Cerastoderma edule in Galicia (NW Spain)

The cockle Cerastoderma edule fishery has traditionally been the most important shellfish species in terms of biomass in Galicia (NW Spain). In the course of a survey of the histopathological conditions affecting this species in the Ria of Arousa, a haplosporidan parasite that had not been observed in Galicia was detected in one of the most productive cockle beds of Galicia. Uni‐ and binucleate cells and multinucleate plasmodia were observed in the connective tissue mainly in the digestive area, gills and gonad. The parasite showed low prevalence, and it was not associated with abnormal cockle mortality. Molecular identification showed that this parasite was closely related to the haplosporidan Minchinia mercenariae that had been reported infecting hard clams Mercenaria mercenaria from the Atlantic coast of the United States. The molecular characterization of its SSU rDNA region allowed obtaining a fragment of 1,796 bp showing 98% homology with M. mercenariae parasite. Phylogenetic analysis supported this identification as this parasite was clustered in the same clade as M. mercenariae from the United States and other M. mercenariae‐like sequences from the UK, with bootstrap value of 99%. The occurrence of M. mercenariae‐like parasites infecting molluscs outside the United States is confirmed.     

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.     

A novel approach to denitrification processes in a zero-discharge recirculating system for small-scale urban aquaculture

This paper presents an innovative process to solve the nitrate build-up problem in recirculating aquaculture systems (RAS). The novel aspects of the process lie in a denitrification bioreactor system that uses solid cotton wool as the primary carbon source and a unique degassing chamber. In the latter, the water is physically stripped of dissolved gaseous O₂ (by means of a Venturi vacuum tube), and the subsequent denitrification becomes more efficient due to elimination of the problems of oxygen inhibition of denitrification and aerobic consumption of cotton wool. The cotton wool medium also serves as a physical barrier that traps organic particles, which, in turn, act as an additional carbon source for denitrification. Operation in the proposed system gives an extremely low C/N ratio of 0.82 g of cotton wool/g of nitrate N, which contributes to a significant reduction of biofilter volume. The additional advantage of using solid cotton wool as the carbon source is that it does not release organic residuals into the liquid to be recycled. Operation of the system over a long period consistently produced effluents with low nitrate levels (below 10 mg N/l), and there was only a very small need to replace system water. The overall treatment scheme, also incorporating an aerobic nitrification biofilter and a granular filtration device, produced water of excellent quality, i.e., with near-zero levels of nitrite and ammonia, a sufficiently high pH for aquaculture, and low turbidity. The proposed system thus provides a solution for sustainable small-scale, urban aquaculture operation with a very high recovery of water (over 99%) and minimal waste disposal.     

Fertilization by refrigerator stored sperm of the Indian major carp, Labeo calbasu (Hamilton, 1822)

This study reports on the spermatological properties, and on the development of a protocol for refrigerator storage (4°C) of Labeo calbasu (Hamilton, 1822) sperm for artificial breeding. Volume, motility, concentration and pH of the freshly collected sperm were 2.21 ± 0.53 (μL g^?1 of fish weight) (mean ± SD), 95 ± 1 (%), 1.93 ± 0.44 × 10⁹ (cells mL^?1) and 7.56 ± 0.17 respectively. Sperm activation was evaluated at different osmolalities of NaCl solution, and motility ceased completely when osmolality of the extender was ≥287 mOsmol kg^?1. Sperm retained motility for 24, 72 and 108 h, after refrigerator storage when sperm were undiluted, suspended in Alsever's solution and suspended in Alsever's solution containing 5% methanol respectively. Fertilization rate of fresh eggs with sperm stored at 4°C in Alsever's solution and Alsever's solution containing 5% methanol was 77% and 60% with a hatching rate of 60% and 43% respectively. The fertilization and hatching success of the stored sperm suggests potential to use refrigeration for transporting genetic material to hatcheries for artificial breeding of L. calbasu in Bangladesh.