【作者】 王晓辉；

【导师】 韩博平；

【作者基本信息】 暨南大学 ， 水生生物学， 2009， 博士

【摘要】 为了解水库自然放养鱼类和开展生态方法改善水库水质的可能性,根据水库鱼类放养情况和生态特征,在甘村水库进行大型围隔实验,对显岗水库进行局部大水面放养殖结构调整,在大镜山水库实施浮床植物为核心的水质改善措施。本论文以浮游动物为对象,了解实验和自然条件下,鱼类放养殖模式和以浮床植物为主体的生态工程措施下浮游动物群落结构的变化和响应。于2007年3月至5月在甘村水库进行大型围隔实验,实验设置鲢、鳙生物量比为7:3、3:7和无鱼三个实验组,每组三个平行。围隔中鲢、鳙混养密度与水库养殖密度相同,为16.7g m~3,以每周一次的频率采样,共9次采样。分析比较了鲢、鳙混养对浮游动物群落的影响。有鱼围隔与无鱼围隔中共检到轮虫33种、枝角类6种和桡足类5种。轮虫主要以热带地区常见的角突臂尾轮虫(Brachionus angularis)、剪形臂尾轮虫(B.forficula)、对棘异尾轮虫(Trich.stylata)、裂痕龟纹轮虫(Anuraeopsis fissa)、螺形龟甲轮虫(Keratellacochlearis)、广生多肢轮虫(Polyarthra vulgaris)和叉角拟聚花轮虫(Conochilus dossnarius)为优势种;枝角类以微型裸腹溞(Moina micrura)为优势种;桡足类成体以台湾温剑水蚤(Thermcyclops taihokuensis)为优势种。有鱼围隔和无鱼围隔中的后生浮游动物的种类数和丰度均以体长在200μm以下的小型浮游动物为主,主要是轮虫和无节幼体。有鱼围隔与无鱼围隔中轮虫优势种更替不明显。鲢鳙鱼的捕食,导致养鱼围隔中的轮虫相对丰度较无鱼围隔中的轮虫相对丰度高;轮虫、枝角类和桡足类丰度、生物量显著下降。可能由于鲢鳙食性上的重叠,两种鲢鳙放养比例围隔中的浮游动物丰度、生物量和个体大小差异不明显。显岗水库是广东省典型高产水库,水库相对较浅,处于中度富营养化水平。2007年6月至2009年2月对显岗水库湖泊区进行每月一次的浮游动物采样,共19次,分析水库中浮游动物群落结构特征。显岗水库的后生浮游动物共有41种,其中30种为轮虫,轮虫优势种主要是角突臂尾轮虫、剪形臂尾轮虫、广生多肢轮虫、螺形龟甲轮虫和对棘异尾轮虫。枝角类7种,长额象鼻溞(Bosmina longirostris)为优势种。桡足类4种,台湾温剑水蚤为桡足类成体优势种。与同地区其它水体相比,轮虫的种类数较少,但丰度较其它水体高。丰度表现为丰水期丰度低,枯水期丰度相对较高。生物量表现出了与丰度相反的季节性变化。CCA结果表明降雨量为影响浮游动物群落季节变化的主要非生物因子。于2007年6月至2009年2月在显岗水库的小型库湾(28公顷)进行大水面养殖实验,实验设置鳙单养(2007年9月-2008年7月)、鲢、鳙生物量比为7:3(2008年9月-2009年7月),密度为15g m~2,与水库鲢、鳙实际养殖密度(30g m~2)、生物量比为3:7比较,以每月一次的频率采样,共19次采样。分析比较了不同比例和密度下鲢、鳙混养对浮游动物群落的影响。不同鲢鳙混养下的轮虫优势种更替不明显。2007年9月-2008年7月库湾内鳙单养较同期库湾外鲢鳙3:7下的枝角类和台湾温剑水蚤及其桡足幼体的丰度和生物量显著性降低,可能由于库湾外12月和3月捕鱼,使鲢、鳙和野杂鱼对浮游动物的捕食压力降低所致。水库存留的大量罗非鱼及其它野杂鱼对浮游动物的捕食可能是导致2007年9月-2008年2月库湾内鳙单养与2008年9月-2009年2月库湾内鲢鳙7:3以及2008年9月-2009年2月库湾内鲢鳙7:3和2008年9月-2009年2月库湾外鲢鳙3:7下的后生浮游动物丰度和生物量差异不显著的原因。于2006年7月至2008年12月,对大镜山水库非植物工程区、植物工程区内的浮游动物采样,分析了探讨了以浮床植物为核心的水质改善工程对浮游动物群落的影响。36次采样共检到轮虫36种、枝角类5种和桡足类9种。角突臂尾轮虫和剪形臂尾轮虫为轮虫最主要的优势种。长额象鼻溞为枝角类的优势种,中华窄腹剑水蚤(Limnoithona sisnensis)为桡足类第一优势种,该种对咸水有较强的适应能力,是通过河流调水引入大镜山水库。抽水入库量、降雨量是影响后生浮游动物丰度季节变化的主要因子。植物工程区与非植物非工程区丰度以200μm以下的小型浮游动物为主,轮虫和无节幼体是丰度的主要贡献者。植物工程区与非植物工程区轮虫、甲壳类丰度和生物量无显著性差异。可能是不同工程区相通,但由于条件限制,未能进行鱼类结构调整所致。郝氏皱甲轮虫(Ploesoma hudsoni)、污前翼轮虫(Proales sordida)和高跷轮虫(Scaridium longicaudum)三种寡营养指示种出现在以浮床植物为核心的水质改善工程后期。而富营养化水体中的优势种如角突臂尾轮虫、剪形臂尾轮虫、对棘异尾轮虫和长额象鼻溞的丰度降低。更多还原

【Abstract】 Reservoirs are man-made water bodies that play a critical role in mitigating the conflict between water demand and supply in industrial,agricultural and daily life.Since there are many reservoirs in Guangdong Province and the majority is becoming more and more eutrophic,we conducted manipulation experiments in Gangcun Reservoir,Xiangang Reservoir and Dajingshan Reservoir with an objective of regulating ecosystem structure against eutrophication.This thesis aims to understand response of zooplankton community to experimental manipulations.Silver carp and bighead carp are the most common fish in tropical reservoirs;their mixed culture is typical of the fishery in tropical reservoirs.The responses of zooplankton to this culture mode were assessed in large enclosures from March 2007 to May 2007.The ratio of silver carp and bighead carp biomass levels was set as follows:0:0,3:7 and 7:3.The density of fish in the fish group was 16.7g.m^-3.The meta-zooplankton was composed of 33 species of rotifers,6 species of cladocerans and 5 species of copepods.Rotifers were dominated by Brachionus angularis,Brachionus forficula,Trichocerca stylata,Anuraeopsis fissa,Polyarthra spp., Conochilus dossuarius and Keratella cochlearis.Moina micrura was the dominant species of cladocera.In Copepoda,Thermocyclops taihokuensis was the most abundant species.The species and abundance was contributed by small-sized species with a body size less than 200μm, such as rotifers and copepod nauplii.The dominant species did not show an evident temporal succession.Relative abundance of rotifers in fish enclosures was higher than that in fishless enclosure due to predation of fishes on big zooplankton,and the abundance of rotifers,cladocera and copepods decreased significantly in fish enclosures.But the abundance and biomass of zooplankton at different ratios of silver carpand bighead carp were similar as the food niche of silver carp and bighead carp overlaps.Xiangang Reservoir is a high fishery yield reservoir,in which silver carp and bighead are mixedly cultured in a biomass ratio of 3:7.In order to understand the community structure of the zooplankton in tropical shallow reservoirs with high fishery yield,zooplankton was sampled in the pelagic zone of this reservoir from June 2007 to February 2009.The meta-zooplankton was composed of 30 species rotifers,7 species cladocerans and 4 species of copepods.Rotifers was dominated by Brachionus angularis,Brachionus forficula,T.stylata,Polyarhtra sp.and K. cochlearis.Bosmina longirostris was the dominant cladoceran.In copepoda,T.taihokuensis was the most abundant species.In the above three groups,the rotifers dominate in species number and total abundance.The total abundance of zooplankton was higher in dry season than flood season,but the total biomass changed inversely.The analysis with CCA showed the precipitation was the most important factor influencing the dynamics of meta-zooplankton.We examined the impact of different stocking levels of fish and different ratios of silver carp and bighead carp in a large scale（667 ha.） and an small enclosured bay（28 ha.） from september 2007 to February 2009 in Xiangang Reservoir.The inside fish biomass of the experimental bay was about 15gm²,the outside one about 30gm².The biomass ratio of silver carp:bighead carp of small enclosured bay was 0:10（september,2007-July,2008） and 7:3（September,2008-February,2009）,the large scale one was 3:7.Samples of zooplankton were collected monthly to analyze species composition,abundance,biomass,body size and dominant species.The dominant species of rotifer did not show an evident temporal succession with different stocking levels of fish and different ratios of silver carp and bighead carp.The abundance and biomass of crustacean small enclosured bay decreased significantly than ones of large scale because of low predation induced fishing from september 2007 to July 2008 in large scale.The abundance and biomass of zooplankton at small enclosured bay between from September 2007 to February 2008 and from September 2008 to February 2009,and ones of between small enclosured bay and large scale from September 2008 to February 2009 were not significant difference,which resulted from the low predation of Tilapia nilotica and other rough fishes.To understand the effect of floating macrophyte rafts on zooplankton in Dajingshan Reservoir, pelagic zooplankton was investigated monthly or biweekly inside in experimental zones with macrophyte and without macrophte from July 2006 to December 2008.The meta-zooplankton was composed of 36 species of rotifers,5 species of cladocerans and 9 species of copepods. Rotifers were dominated by Brachionus,such as Brachionus angularis and Brachionus forficula. Bosmina longirostris was the dominant species of cladocera.In copepoda,Limnoithona sinensis was the most abundant species,Limnoithona sisnensis is a small-sized species.It can adapt to high salinity,and invade Dajingshan Reservoir with water pumped from the Xijiang River. Precipitation and pumped water were the most important factors influencing the dynamics of the meta-zooplankton,and they significantly modified the effect of temperature.The zooplankton abundance of three zones was composed of small-sized species with a body size less than 200^tm, such as rotifers and copepod nauplii.The abundance and biomass ofrotifers and cructacean were not significant difference between experimental zones with macrophyte and without macrophyte because three experimental zones were not isolated absolutely and the composition of fishes were adjusted.Towards the third years after the bio-engineering,some oligotrophy indicators, such as Ploesoma hudsoni,Proales sordida,and Scaridium longicaudum occurred,and the abundance of eutrophic indicators such as B.angularis,B.forficula,T.stylata,and B. longirostris,decreased.更多还原