富藻养殖水体中金鱼藻和篦齿眼子菜的抑藻效果研究

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。     

千岛湖浮游植物群落结构时空分布及其与环境因子的关系

研究千岛湖浮游植物群落结构特征及其与主要环境因子的关联性,为了解千岛湖水环境变动规律及水环境的保护与管理提供依据。沿水流方向在水库上中下游依次设置5个采样点,2010年对千岛湖浮游植物群落开展了周年调查。共鉴定出浮游植物8门223种,其物种数、密度和生物量均主要由硅藻、蓝藻和绿藻组成。不同浮游植物门类物种数、密度和生物量组成比例站点间无显著差异;群落总密度和生物量站点间无显著差异,但有显著的季节变化,它们的垂直分布均呈现先增加后下降的趋势,在4~8 m水层具有最大值。Shannon多样性和Pielou均匀度指数在空间和季节间均无显著差异,但Margalef丰富度指数存在显著的季节和空间差异。聚类分析(CA)和多维尺度分析(MDS)表明,藻类物种组成在站点间无显著差异,但具有显著的季节变化,即分化为春季、冬季和夏秋季3种群落类型,春季群落主要特征种为颗粒直链藻及其狭窄变种和尖尾蓝隐藻,冬季为水华鱼腥藻、颗粒直链藻狭窄变种和脆杆藻,夏秋群落为网状空星藻、水华鱼腥藻和梅尼小环藻。相关性分析表明,浮游植物密度和生物量与水温、pH值、CODMn和Chl-a显著正相关,与SD和DO显著负相关;生物量与Si O2-3-Si显著正相关。典范对应分析(CCA)显示,水温、DO和NO-3-N及pH值是影响浮游植物时空分布的主要因子。     

应用特征色素研究淡水鱼不同养殖模式对浮游植物群落结构的影响

为探究鲢鱼(Hypophthalmichthys molitrix)对草鱼(Ctenopharyngodon idellus)-鲢鱼复合养殖水体中浮游植物群落结构的影响,2011年8月到10月在山东省淡水水产研究所,利用高效液相色谱技术(HPLC)和显微镜计数法定量研究了单养草鱼(G组)、单养鲢鱼(S组)、草鲢混养(GS组)三种养殖模式下水体中浮游植物群落结构的变化。结果表明:在不同养殖水体中,浮游植物的群落结构存在显著性不同。S组浮游植物生物量远低于G组和GS组,且不同水体中的优势种也有所不同,S组以绿藻门的栅藻(Scenedesmaceaespp.)、新月藻(Closterium Nitzsch spp.)和硅藻门的曲壳藻(Achnanthes sp.)为优势种;G组以蓝藻门的席藻(Phormidium spp.)、束丝藻(Aphamnizomenon sp.)和硅藻门的针杆藻(Synedra spp.)为优势种;GS组以绿藻门的栅藻(Scenedesmaceae spp.)为优势种。在测定出的光合色素中,含量最高的为叶绿素a(Chlorophylla),其次为叶绿素a酸酯(Chlorophyllide a)。除别黄素(Alloxanthin)与隐藻的生物量不显著相关外,其他被鉴定出的特征色素如岩藻黄素(Fucoxanthin)、叶黄素(Lutein)、玉米黄素(Zeaxanthin)、叶绿素b(Chlorophyllb)、多甲藻黄素(Peridinin)分别与硅藻、绿藻、蓝藻、绿藻、甲藻的生物量显著相关(P<0.01)。将特征色素与营养盐进行相关性分析,结果显示,在S组内,TN含量与TChla、Chlb、Fuco和Lut均显著负相关(P<0.05),NH4+-N含量与TChla、Fuco显著负相关(P<0.05),TP含量与Fuco显著负相关(P<0.05)。在S组和GS组内,NO3--N含量与Fuco显著负相关(P<0.05)。所有处理组与NO2--N和PO34--P均无明显相关性(P>0.05)。鲢鱼的排泄活动对浮游植物群落结构也有影响。     

Nualgi营养素、硅藻藻种对池塘水质和浮游植物的短期效应研究

为探讨短期内Nualgi营养素对池塘水质和藻类群落结构的影响,本研究在池塘中的不透水有底帆布围隔内共设计了4个试验组,依次分别添加Nualgi营养素(M1组)、补充硅藻藻种(M2组)、同时添加Nualgi营养素并补充硅藻藻种(M3组)、不做任何处理的空白对照(C组)。经过近一个月的试验,结果显示:各组的pH值、DO、TN、TP之间没有显著性差异;Nualgi可以显著降低水体中IP的含量,M1组和M3组的IP显著低于M2组和C组;M1组、M2组和M3组中的NH_4~+-N、NO_2~--N和CODMn含量显著低于C组,表明Nualgi和硅藻藻种都可以显著降低水体中NH_4~+-N、NO_2~--N和CODMn的含量,对养殖水质具有显著的调控效果。试验各组的藻类种群极为丰富,试验期间共检出浮游植物7门109属186种,其中绿藻门47属86种,硅藻门26属48种,蓝藻门18属27种,裸藻门11属17种,甲藻门3属3种,隐藻门2属3种,金藻门2属2种。结果显示:添加Nualgi和补充硅藻藻种都可以有效提高水体中硅藻的生物量并抑制绿藻和蓝藻的生长,同时可以改变水体中浮游植物的群落结构,试验进行到第20天时,M1组、M2组和M3组中硅藻的生物量均显著高于C组,绿藻和蓝藻的生物量显著低于C组。试验中,颗粒直链藻在M1组、M2组和M3组中成为优势藻种,但并未在C组中成为优势藻种,小空星藻和四足十字藻仅在C组中成为优势藻种,四尾栅藻在M1组、M2组和C组中均成为优势藻种。在试验期内,各试验组之间的多样性指数没有显著差异,香农-威纳指数均在2.00以上,表明Nualgi和硅藻藻种并没有影响到水体中藻类的多样性。     

不同种类浮游植物对CO2浓度升高的响应

本研究采用实验生态学的方法，以金藻、硅藻、绿藻3个门中的4种常见饵料藻叉鞭金藻(Dicrateria sp.)、三角褐指藻(Phaeodactylum tricornutum)、小球藻(Chlorella vulgaris)和亚心形扁藻(Platymonas subcordiformis)为研究对象，分析比较不同浮游植物的细胞数量和质量对CO2浓度升高引起的海水酸化的响应情况。结果显示，与对照组相比，(1) CO2浓度升高显著提高了这4种藻的生长速率(P<0.05)；其中，亚心形扁藻平均比生长速率最高，比对照组高出13.5%；小球藻次之，为5.9%；叉鞭金藻和三角褐指藻均为2.2%。(2) CO2浓度升高使浮游植物细胞内的碳(C)含量增加、氮(N)含量降低，C/N提高；种间差异较大，其中，亚心形扁藻的C/N、C/P值、小球藻的C/P值和三角褐指藻的C/N值显著提高，叉鞭金藻不显著。(3) CO2浓度升高使小球藻单位细胞叶绿素a含量显著提高，小球藻通过提高光合作用能力促进生长，而另外3种藻叶绿素a含量与对照组无显著差异；三角褐指藻最大光化学量子产量(Fv/Fm)在实验初期显著升高；叉鞭金藻非光化学淬灭(NPQ)显著降低，快速光曲线初始斜率(α)显著增加；三角褐指藻和亚心形扁藻潜在的最大光合作用能力(rETRmax)显著升高(P<0.05)，但CO2浓度升高对4种藻的光化学淬灭(qP)均没有显著影响(P>0.05)。可见，亚心形扁藻、小球藻和三角褐指藻在高CO2浓度下虽然生长速率加快，但营养质量降低。不同种类的浮游植物对CO2浓度升高的响应不同，这种差异可能会使未来海洋浮游植物群落结构发生变化；浮游植物C/N、C/P值的改变可能通过食物链对次级生产者，诸如浮游动物、滤食性贝类等产生影响。     

不同种类浮游植物对CO_2浓度升高的响应

本研究采用实验生态学的方法,以金藻、硅藻、绿藻3个门中的4种常见饵料藻叉鞭金藻(Dicrateriasp.)、三角褐指藻(Phaeodactylumtricornutum)、小球藻(Chlorellavulgaris)和亚心形扁藻(Platymonas subcordiformis)为研究对象,分析比较不同浮游植物的细胞数量和质量对CO_2浓度升高引起的海水酸化的响应情况。结果显示,与对照组相比,(1)CO_2浓度升高显著提高了这4种藻的生长速率(P0.05);其中,亚心形扁藻平均比生长速率最高,比对照组高出13.5%;小球藻次之,为5.9%;叉鞭金藻和三角褐指藻均为2.2%。(2) CO_2浓度升高使浮游植物细胞内的碳(C)含量增加、氮(N)含量降低,C/N提高;种间差异较大,其中,亚心形扁藻的C/N、C/P值、小球藻的C/P值和三角褐指藻的C/N值显著提高,叉鞭金藻不显著。(3)CO_2浓度升高使小球藻单位细胞叶绿素a含量显著提高,小球藻通过提高光合作用能力促进生长,而另外3种藻叶绿素a含量与对照组无显著差异;三角褐指藻最大光化学量子产量(Fv/Fm)在实验初期显著升高;叉鞭金藻非光化学淬灭(NPQ)显著降低,快速光曲线初始斜率(α)显著增加;三角褐指藻和亚心形扁藻潜在的最大光合作用能力(rETR_(max))显著升高(P0.05),但CO_2浓度升高对4种藻的光化学淬灭(qP)均没有显著影响(P0.05)。可见,亚心形扁藻、小球藻和三角褐指藻在高CO_2浓度下虽然生长速率加快,但营养质量降低。不同种类的浮游植物对CO_2浓度升高的响应不同,这种差异可能会使未来海洋浮游植物群落结构发生变化;浮游植物C/N、C/P值的改变可能通过食物链对次级生产者,诸如浮游动物、滤食性贝类等产生影响。     

光合细菌强化对精养鱼塘藻类群落结构的影响

通过定期向池塘投加光合细菌,研究了有益微生物强化对精养鱼塘浮游藻类群落结构的影响。结果显示:光合细菌强化塘(试验塘)藻类组成以绿藻、硅藻为主,养殖前期(5—6月初),以针杆藻、直链藻等占优势,中后期(7—9月)则以绿球藻、栅藻、盘星藻、小环藻、菱形藻等为优势种,水色呈淡绿、黄褐色等良好状态;而对照塘藻类组成在前期与试验塘没有明显差异,但在中后期出现明显变化,以微囊藻、颤藻、鱼腥藻、席藻等蓝藻占优势。试验塘藻类生物量显著低于对照塘(P<0.05),且对照塘生物量波动变化大,蓝藻数量所占比例可高达77.6%,远高于试验塘蓝藻比例(均值低于25.0%);此外,藻类Shannon-Wiener指数、Pielou指数试验塘均大于对照塘。结果表明:光合细菌的定期添加有效控制了蓝藻增值,保持了藻类多样性,使精养鱼塘藻相趋于稳定,有利池塘养殖。     

微藻饵料对紫海胆浮游幼体生长及存活影响的研究

文章采用湛江叉鞭金藻(Dicrateria zhanjiangensis)、纤细角毛藻(Chaetoceros gracilis)、绿色巴夫藻(Pavlova viridis)、扁藻(Platymonas subcordiformis)、小球藻(Chlorella vulgaris)及混合藻(金藻和角毛藻1∶1混合)投喂紫海胆(Anthocidaris crassispina),研究了微藻饵料对紫海胆浮游幼体生长发育的影响。结果表明,不同饵料对紫海胆浮游幼体生长发育的效果有差异,金藻是最佳饵料品种,角毛藻次之,其后分别为巴夫藻、小球藻和混合藻,扁藻不适于作为紫海胆浮游幼体的开口饵料。就饵料种类而言,金藻作为紫海胆浮游幼体饵料的成活率可达(23.12±1.8)%,显著高于其他单胞藻类(P<0.05)。就发育速度而言,以角毛藻和金藻混合喂食的海胆浮游幼体整体发育速度最快,幼体平均体长为(885.25±30.49)μm,显著高于其他5种处理(P<0.05);投喂巴夫藻的浮游幼体前期生长较慢,体长为(337.98±24.56)μm,后期较其他单胞藻类生长快,体长可达(580±32.95)μm,适宜作为紫海胆浮游幼体后期饵料。     

天目湖沙河水库水质时空分布特征及其与浮游植物群落的关系

基于2012年天目湖沙河水库逐月水质及浮游植物群落结构的监测,采用主成分分析及典范对应分析,对沙河水库水质时空分布特征及其对浮游植物群落演替的影响进行了分析。结果表明,沙河水库透明度(SD)、悬浮物(SS)、高锰酸盐指数(CODMn)、叶绿素a(Chl a)、总磷(TP)、总氮(TN)等主要水质因子既有明显的季节变化,也存在显著的空间分布差异,浮游植物生物量和群落结构也表现出显著的季节演替。从丰度上看,蓝藻门的席藻全年都是优势种,但冬、春季节硅藻门和隐藻门藻类丰度显著增高。从生物量上看,春季的优势种为硅藻门的针杆藻,是沙河水库水体透明度的主要影响因子。主成分分析表明,沙河水库的氮和磷具有明显不同的时间变化规律。典范对应分析表明,水温、pH、溶解性总氮、SD与藻类生物量的季节演替关系密切,蓝藻、硅藻生物量与水温、溶解性总磷呈正相关,与硝态氮浓度呈负相关。研究结果表明,天目湖沙河水库水质时空差异与浮游植物种群结构的时空分布关系密切,降低氮、磷浓度对沙河水库富营养化控制及水质的保护都非常重要,但在不同季节氮、磷的相对重要性不同。农业活动,如茶园的大面积开发及旅游业活动是影响天目湖水质的两个重要因素。     

长江口东滩湿地不同盐沼植被样地内浮游植物群落结构的差异

根据2015年5-12月在长江口东滩盐沼湿地水域采集的浮游植物监测数据,分析了海三棱藨草[Scirpus mariqueter(编号:HS)]、互花米草(Spartina alterniflora)入侵早期(编号:HZ)和互花米草入侵后期阶段(编号:HH)、芦苇[Phragmites australis(编号:LW)]等4种植被样地浮游植物群落结构的时空差异。结果表明,共发现浮游植物64种(或属),隶属4个门。硅藻门种类最多,有48种(或属),占总种类数的73.8%;其次为蓝藻门种类,有10种(或属);绿藻门有6种。优势种为中肋骨条藻(Skeletonema costatum)(Y=0.76)、洛氏菱形藻(Nitzschia lorenziana)(Y=0.03)和近缘斜纹藻(Pleurosigma affine)(Y=0.02)等3种。5-8月盐沼植被区浮游植物的种类数相对较高,而9-12月(秋季至冬初)种类数明显下降。各个植被样地中硅藻的月平均丰度均明显高于其它藻类,而甲藻丰度最低。HS和HZ植被样地中的浮游植物群落的种类数和丰度并无显著性差异(P0.05),HH和LW样地浮游植物的种类数和丰度同样无显著性差异;前2种生境浮游植物的月平均丰度是后2种生境的3.8倍,这主要是由于硅藻的丰度差异较大造成的。从物种丰富度指数(D)来看,两两生境间物种丰富度指数未发现显著性差异(P0.05)。Shannon指数(H')变化趋势类似于均匀度指数(J),5-8月和12月H'值相对较高。从群落聚类和排序结果来看,在空间上4种植被样地浮游植物群落难以区分开;而在时间上大致分为2组[即5-8月(春初至夏末)与9-12月(秋季至冬初)]。总体来说,不同植被样地浮游植物群落动态月份差异较大,同一高程植被样地浮游植物群落差异不显著。研究表明,长江口盐沼植被生境浮游植物群落组成与邻近水体有着较大的不同,具有独特的生态功能。     

Survival, growth, food conversion efficiency and plasma osmolality of juvenile Siganus guttatus (Bloch, 1787): experimental analyses of salinity effects

We studied the effects of salinity on survival, growth, food conversion efficiency and plasma osmolality of juvenile Siganus guttatus in two independent experiments. In the first experiment, fish were transferred from 30 ‰ salinity to freshwater, 5, 10, 20 and 30 ‰ salinities for 192 h. No fish died when transferred directly from 30 ‰ to salinities >5 ‰. However, all fish died in the freshwater treatment. In the second experiment, survival, growth, feeding rate, food conversion efficiency and plasma osmolality of fish were analyzed during 6 weeks in salinities of 5, 10, 20 and 30 ‰ (control). At the end of this experiment, the final weight and the specific growth rate of fish were significantly greater at 10 ‰ than fish in all other treatments. Feeding rate increased significantly with decreasing salinity: 10 ‰ > 20 ‰ > 30 ‰. However, the food conversion efficiency was not significantly different between fish in any treatment. Plasma osmolality of fish in 20 and 30 ‰ salinity was significantly greater than fish reared at 10 or 5 ‰. A salinity of 13.95 ‰ (411.88 mOsmol/kg) was the point of isosmolality for juvenile S. guttatus.     

水体营养水平及附着藻类对苦草生长的影响

为研究不同水体营养水平及附着藻类对沉水植物生长的影响,选择苦草(Vallisneria natans)作为研究对象,在4种水体营养水平下进行42 d的室内试验。结果表明:试验结束时,中营养及富营养处理组苦草的相对生长率、超氧化物歧化酶(SOD)活性、丙二醛(MDA)含量和附着藻类生物量与贫营养及重富营养处理组具有显著性差异(P<0.05);贫营养处理组苦草的可溶性糖含量显著高于其它处理组(P<0.05);苦草氮磷含量及可溶性蛋白含量与水体营养水平呈明显正相关,且贫营养及中营养处理组与富营养及重富营养处理组之间差异显著(P<0.05);各处理组水体叶绿素a含量差异不明显。表明在中营养(TN=0.8 mg/L,TP=0.08 mg/L)条件下,苦草的生长情况最佳。     

Effects of different salinity and temperatures on the growth,survival, haematocrit and blood biochemistry of Goldfish (Carassius auratus)

The aim of the present study was to investigate the effects of different salinities (0‰, 6‰ and 12‰) and temperatures (23, 27 and 31 °C) on the food consumption, growth, blood biochemistry and haematocrit of Goldfish. After 45 days of exposure to different salinities and temperatures, Goldfish showed a good adaptation to these salinities and temperatures in terms of blood biochemistry (glucose and triglyceride) and haematocrit. Salinities (0‰ and 6‰) and temperatures (23 and 27 °C) did not affect the weight gain, specific growth rate, final biomass and feed conversion rates, but these parameters were significant (P<0.05) at 12‰ salinity and 31 °C temperature. Plasma total protein levels decreased with the increase in salinity (P<0.05), while they were independent of temperature. In conclusion, Carassius auratus, a freshwater stenohaline fish, showed good growth in saline waters with maximum 12‰ salinity and 31 °C temperature.     

Low salinity increases survival,body weight and development in tadpoles of the Chinese edible frog Hoplobatrachus rugulosus

Water salinity affects survival, growth and metamorphosis of anuran tadpoles. Hoplobatrachus rugulosus is considered not only as a freshwater amphibian but is also found in brackish wetlands. However, whether salinity change interferes with hatching, survival, body mass and development of H. rugulosus tadpoles is unknown. We found that salinity levels of <4‰ did not affect of survival or hatching of H. rugulosus eggs. At an early larval stage, tadpoles could tolerate up to 9‰ salinity for 96 h; however, body water content decreased when salinity was >5‰. After a 3‐week experiment, body weights of tadpoles exposed to 2‰ and 4‰ salinities were higher but that of the 6‰ group was lower compared with the 0‰ group. More than 90% of tadpoles exposed to 2‰ and 4‰ salinity showed complete metamorphosis. Salinity levels <4‰ promoted survival of tadpoles better than 0‰, whereas none of tadpoles in the 6‰ group became juvenile frogs in 50 days. Time taken to reach metamorphosis was shorter for 2‰ and 4‰ (47.22 ± 0.28 and 47.26 ± 0.33 days, respectively) than for 0‰ (49.31 ± 0.35 days). Juvenile frogs in the 2‰ group had greater body weight than the control. It could be concluded that salinity of <4‰ increased survival and body weight of H. rugulosus tadpoles, and shortened the time taken to reach metamorphosis.     

Osmoregulation,growth and moulting cycles of the giant freshwater prawn (Macrobrachium rosenbergii) at different salinities

The giant freshwater prawn, Macrobrachium rosenbergii, is a species with a high commercial value in aquaculture. Two experiments were performed to determine the effects of salinities on the osmoregulation, growth and molting cycles of M. rosenbergii during growout. The first experiment was designed to determine whether these animals are capable of adapting to the changes in salinity seen in salinity intrusions in tropical deltas, with an incremental increase in salinity of 3‰ per day from 0‰ to 30‰ Haemolymph osmolality was rapidly regulated up to salinities of 15‰ , whereas animals conformed at higher salinities. The second experiment determined the growth, moulting cycle, osmolality, muscle water content and mortality during a 4‐month experiment at 0‰, 15‰ or 25‰ salinity. The weight gains in 0‰ and 15‰ were not significantly different and were comparable to the growth rates achieved in production farms with body mass increases of 2.6 and 2.3‐fold their initial body mass, respectively, after 4 months. The 25‰ group suffered from low growth, high mortality and a significantly lower moulting frequency. These data show that this species can be reared in brackish water up to 15‰, allowing for farming in the large areas impacted by salt water intrusions in tropical deltas.     

Nutritional Properties of the Marine Rotifer Brachionus plicatilis Fed the Freshwater Microalgae Selenastrum capricornutum

This study examined the effects of storage time on the fatty acid composition of freshwater Selenastrum capricornutum algal paste under 4 C refrigeration, the fatty acid composition of rotifers fed the fresh and stored algal paste, and the toxicological properties of the algal paste. Microalgae were produced in a hydraulically integrated serial turbidostat algal reactor (HIS-TAR), harvested as a paste, refrigerated and analyzed every 2 wk. Fresh Selenastrum capricornutum paste had almost three times greater concentration of unsaturated fatty acids than saturated fatty acids. Over 50% of the unsaturated fatty acids were made up of n-3 and n-6 fatty acids. Total unsaturated, n-3 group and n-6 group fatty acids decreased ( P 0.05) during storage, including the nutritionally important fatty acids (C20:4n6, C20:5n3, C22: 6n3). Rotifers fed 2– and 4-wk-old algal paste had a significantly lower ( P 0.05) total unsaturated fatty acid percentage and significantly greater ( P 0.05) total saturated fatty acids than those fed fresh algae. There were no significant changes in the n-6 group fatty acid level in the 4-wk-old paste feeding study or for the n-3 or n-6 groups in the 2-wk-old paste feeding study as compared to fresh algae. The levels of the three nutritionally important fatty acids (C20:4n6, C20:5n3, C22:6n3) did not differ between rotifers fed fresh and stored algae. Stored algae did not present toxicity to rotifers and Daphnia at the normal feeding concentration. These results indicated that the use of refrigerated freshwater algal paste for production of rotifers results in live feed with adequate nutritional properties for marine larviculture. This could eliminate the costs associated with production of marine algae, which could be replaced with freshwater algae, and may provide an alternative to cryopreservation.     

中华鳖不同生态养殖模式对池塘水环境及养殖效果的影响

利用条件相近的两组池塘,对中华鳖(Trionyx sinensis)的两种生态模式(Ⅰ组:中华鳖-吃食性鱼类鲤和草鱼模式;Ⅱ组:中华鳖-杂食性水生动物鲫和螺模式)对池塘水环境以及养殖效果的影响进行对比试验。结果表明,Ⅱ组CODMn在7、8、和9月显著低于Ⅰ组(P<0.05),NH3在6、7、8和9月显著低于Ⅰ组(P<0.05),TP在7月和8月显著低于Ⅰ组(P<0.05),TN在6、7和8月显著低于Ⅰ组(P<0.05),NO2--N在6月和7月显著低于Ⅰ组(P<0.05),Ⅱ组水环境质量较Ⅰ组好。Ⅱ组检出藻类47种,Ⅰ组34种,Ⅱ组种类显著增多(P<0.05);Ⅰ组蓝藻重量占83.18%,硅藻2.98%,隐藻2.65%,甲藻0%,Ⅱ组蓝藻58.59%,硅藻13.44%,隐藻14.00%,甲藻7.07%,Ⅱ组蓝藻明显下降,而硅藻、隐藻、甲藻明显上升(P<0.05)。6月Ⅰ组平均生物量4.18mg/L,Ⅱ组2.57mg/L,8月Ⅰ组29.04mg/L,Ⅱ组5.41mg/L,6月和8月Ⅰ组生物量均显著高于Ⅱ组(P<0.05)。Ⅰ组Shannon-Wiener指数H’在6月和8月均值分别为2.117和0.7467,Ⅱ组均值分别为2.5427和1.0178,Ⅱ组6月和8月H’均明显增加(P<0.05);在6月,Ⅱ组Margalef丰富度指数d为1.8516,Ⅰ组为1.2499,Ⅱ组较Ⅰ组上升明显(P<0.05);两组的Pielou匀度均指数J差别不大。Ⅱ组中华鳖平均产量11782.5kg/hm2,显著高于Ⅰ组11482.5kg/hm2(P<0.05)。     

鱼蚌混养对池塘水质、藻相结构及三角帆蚌生长的影响

2012年4月26日—2012年12月12日通过在鲢鳙鱼养殖池塘中放养不同密度的三角帆蚌,研究不同三角帆蚌放养比例对鲢鳙鱼养殖池塘中水质、藻相结构及三角帆蚌生长的影响。实验中,鲢鳙放养比例统一为3∶7,总密度为1.5尾/m3。三角帆蚌放养密度则设置4个水平,分别为单养鲢鳙鱼池塘(0只/m3),低密度三角帆蚌混养池塘(0.8只/m3),中密度三角帆蚌混养池塘(1.0只/m3)和高密度三角帆蚌混养池塘(1.2只/m3)。结果显示,混养三角帆蚌池塘的水化指标(TP、PO4-P、NH3-N、NO2-N和NO3-N)均显著低于单养鱼池塘。中密度三角帆蚌混养池塘除NH3-N和化学需氧量(COD)与低密度三角帆蚌混养池塘无显著差异外,其他各项水化指标均显著低于其他3个池塘,并且极显著低于单养鲢鳙鱼池塘。单养鲢鳙鱼池塘藻类平均密度均极显著高于鱼蚌混养池塘,其中在鱼蚌混养池塘中浮游植物密度与三角帆蚌密度成负相关关系。单养鲢鳙鱼池塘的浮游植物生物量均极显著低于中、高密度鱼蚌混养池塘,并且显著低于低密度混养池塘。浮游植物生物量与三角帆蚌密度成正相关关系,鱼蚌池塘中绿藻和裸藻的生物量在养殖过程中上升显著。低、中密度三角帆蚌混养池塘三角帆蚌存活率均显著高于高密度三角帆蚌混养池塘;低密度混养池塘中蚌湿重、壳长及壳宽相对增长率均为最大,显著高于中、高密度三角帆蚌混养池塘。研究表明,养鱼池塘混养三角帆蚌不仅能改善养殖池塘的水质,还能控制藻类数量,促使绿藻和裸藻等大型藻类的生长,提高养殖水体浮游植物的生物量总量,最终还能有效提高三角帆蚌的存活率及生长率。从改善水质,藻相结构,蚌成活率及生长等指标角度考虑,在鲢鳙鱼养殖池塘中,三角帆蚌最佳放养密度为1.0只/m3。     

Effect of Salinity on Growth,Feed Utilization,and Survival of Tilapia rendalli Under Laboratory Conditions

ABSTRACT

Juvenile T. rendalli were evaluated for 10 weeks to determine the effect of salinity on growth, feed utilization, and survival in tanks. Fish weighing 3.94 ± 0.44 g were stocked into twelve 50-L rectangular tanks at 15 fish /tank. The fish were raised in three salinity levels (5, 10, 15‰, and freshwater as a control). There were three replicate tanks per treatment. After the feeding experiment, a digestibility trial was conducted for two weeks. After 70 days, fish in the 10‰ treatment grew significantly larger (P < 0.05) than those in 5‰, 15‰, and freshwater. T. rendalli cultured in 10‰ had significantly lower feed conversion ratios and higher feed conversion efficiency and protein efficiency ratios. Survival of the fish was significantly (P < 0.05) different and depended on salinity level. The apparent digestibilities of crude protein, fat, ash, and gross energy were significantly higher (P < 0.05) in T. rendalli cultured in the 10‰ salinity treatment. However, apparent digestibility of dry matter did not differ significantly (P < 0.05) between 10‰ and 5‰. The results obtained indicate that 10‰ is optimal for T. rendalli in tank culture.     

发酵豆粕替代藻粉对刺参(Apostichopus japonicus)生长及体组成的影响

为研究发酵豆粕替代藻粉对刺参(Apostichopus japonicus)生长及体组成的影响,以发酵豆粕分别替代基础饲料中的藻粉及鱼粉藻粉混合物(2:15),配制9组等氮实验饲料,饲喂初始体重为17.7 g左右的刺参幼参70 d.结果显示,随替代藻粉比例的升高,实验刺参的增重率及特定生长率先升后降(P＜0.05);随替代混合物比例的升高,D8、D9组增重率及特定生长率显著低于前3组(P＜0.05),但前3组之间无显著差异(P＞0.05);替代藻粉降低了体壁粗脂肪含量(P＜0.05);替代混合物降低了粗灰分含量(P＜0.05);替代藻粉降低了体壁甘氨酸、蛋氨酸及半胱氨酸含量(P＜0.05),提高了苯丙氨酸和组氨酸含量(P＜0.05);替代混合物降低了丝氨酸、苏氨酸、甘氨酸、蛋氨酸、赖氨酸及组氨酸含量(P＜0.05),提高了精氨酸、脯氨酸、苯丙氨酸及半胱氨酸含量(尸＜0.05);替代藻粉降低了体壁Ca、Mg、Fe、Zn、Cu、Cr、Mn及Pb含量(P＜0.05);替代混合物降低了Ca、Mg、Zn、Cu、Cr及Pb含量(P＜0.05),提高了Fe及Mn含量(P＜0.05).以增重率为评价指标,经SAS REG曲线拟合,发酵豆粕替代藻粉的最佳比例为29.75％;经SAS NLIN曲线拟合,替代46.46％的鱼粉藻粉混合物对刺参生长无显著影响.