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1.
以东湖郭郑湖为研究对象,将其生态系统中在质和量方面占重要地位的浮游植物-鲢作为亚系统,研究它们之间的相互作用。比较了夏季两个月中鲢的生长和让其充分摄食后的生长,发现最初20天没有差异,20天后两者开始出现差别。将两者的相互作用模型化,计算的结果是,浮游植物被鲢摄食后密度下降,而鲢得不到充足的饵料,导致生长缓慢。观察此期间的氮平衡,浮游植物所生产的氮几乎全部被鲢利用,但浮游植物所需要的78%的氮又是鲢提供的。这说明在湖区整个生态系统中,此相互作用系统在量的方面是很重要的。  相似文献   

2.
1. We performed two field experiments using different cage sizes to determine the direct and indirect effects of carp on macrophytes and invertebrate community composition in a shallow lake. 2. The presence of carp produced a significant decrease in macrophyte abundance, changes in species composition and decreased abundance and diversity of invertebrates in small (2.5 × 2.5 × 2.0 m) cages. In large exclosures (15 × 5 m), only macrophyte stem length was significantly affected by carp. 3. There was considerable variation in the macrophyte and invertebrate responses to carp on different sides of the lake in the large exclosures, suggesting that wind and wave action are also important variables affecting macrophyte growth and persistence. 4. The data suggest that carp can significantly affect species abundance and diversity of macrophytes and some macroinvertebrates.  相似文献   

3.
围隔中鲢和菹草控藻效果及其生态学意义   总被引:11,自引:0,他引:11  
在滇池沿岸的池塘中 ,构建了面积为 10 0m2 ,水深为 85cm ,底质均为淤泥的四个围隔 ,其中在三个围隔内分别放养密度为 10 0g/m3 、75g/m3 、5 0g/m3 的鲢。它们均在一定程度上控制浮游植物的生物量并改善水体透明度 ,其中初始放养鲢 75g/m3 的围隔控制效果最明显。放养三种密度的鲢在有效控制微囊藻水华的同时 ,原先水体的优势种类发生质的变化 ,水体中浮游植物的多样性也明显增加。放鱼 2个月后 ,在生物操纵的围隔中同时种入菹草 ,在75g/m3 的鲢控藻的围隔中 ,菹草长势良好 ,浮游动物大量出现 ,透明度进一步增加  相似文献   

4.
不同生境草鱼肠道微生物组成和群落特征分析   总被引:1,自引:0,他引:1  
[目的]分析不同生境来源的草鱼前肠、中肠和后肠的微生物组成和群落特征.[方法]利用16S rRNA高通量测序技术比较河流、湖泊、高密度池塘养殖与水库低密度养殖4种不同生境来源的草鱼其前、中、后肠的微生物组成和群落特征.[结果]Venn图、稀释性曲线和Alpha指数分析结果显示,前肠微生物群落多样性以养殖生境草鱼更高,而...  相似文献   

5.
SUMMARY 1. Silver carp, Hypophthalmichthys molitrix (Val.), feeds on both phyto- and zooplankton and has been used in lake biomanipulation studies to suppress algal biomass. Because reports on the effects of silver carp on lake food webs have been contradictory, we conducted an enclosure experiment to test how a moderate biomass of the fish (10 g wet weight m−3) affects phytoplankton and crustacean zooplankton in a mesotrophic temperate reservoir.
2. Phytoplankton biomass <30 μm and particulate organic carbon (POC) <30 μm were significantly higher in enclosures with silver carp than in enclosures without fish, whereas Secchi depth was lower. Total copepod biomass declined strongly in both treatments during the experiment, but it was significantly higher in fish-free enclosures. Daphnid biomass was also consistently higher in enclosures without fish, although this effect was not significant. However, the presence of fish led to a fast and significant decrease in the size at maturity of Daphnia galeata Sars. Thus, the moderate biomass of silver carp had a stronger negative effect on cladoceran zooplankton than on phytoplankton.
3. Based on these results and those of previous studies, we conclude that silver carp should be used for biomanipulation only if the primary aim is to reduce nuisance blooms of large phytoplankton species (e.g. cyanobacteria) that cannot be effectively controlled by large herbivorous zooplankton. Therefore, stocking of silver carp appears to be most appropriate in tropical lakes that are highly productive and naturally lack large cladoceran zooplankton.  相似文献   

6.
Fish behaviour was monitored in 1-m2 tanks each stocked with three 67-g rohu (Labeo rohita). In addition, 80-g common carp (Cyprinus carpio) were stocked at 0, 1 or 2 fish per tank. All tanks were fertilized prior to stocking to stimulate natural food production. In addition, half of the tanks were fed a supplemental diet. Results confirm the general view that rohu mainly lives and feeds in the water column, while common carp is a bottom feeder. In the presence of common carp, rohu increased the time spend grazing on tank wall and bottom, and decreasing grazing time in the water column. Supplemental feeding had a similar, be it less pronounced effect. When both present, rohu and common carp spend 47–52% of their time together. Rohu spends more time close to the bottom in the presence of common carp than when no common carp is present, presumably to profit from increased zooplankton production, triggered by the resuspension of nutrients by burrowing common carp. This was reflected in a higher growth rate of rohu in the presence of carp. These effects were stronger with one common carp per tank than with two common carp. In this study, the results from behavioural observations in tanks nicely complemented results from a pond study analyzing growth, production and food availability. Behavioural observations in tank yielded useful additional information helpful to clarify species interactions and feeding ecology in polyculture ponds.  相似文献   

7.
Biological invasions are projected to be the main driver of biodiversity and ecosystem function loss in lakes in the 21st century. However, the extent of these future losses is difficult to quantify because most invasions are recent and confounded by other stressors. In this study, we quantified the outcome of a century‐old invasion, the introduction of common carp to North America, to illustrate potential consequences of introducing non‐native ecosystem engineers to lakes worldwide. We used the decline in aquatic plant richness and cover as an index of ecological impact across three ecoregions: Great Plains, Eastern Temperate Forests and Northern Forests. Using whole‐lake manipulations, we demonstrated that both submersed plant cover and richness declined exponentially as carp biomass increased such that plant cover was reduced to <10% and species richness was halved in lakes in which carp biomass exceeded 190 kg ha?1. Using catch rates amassed from 2000+ lakes, we showed that carp exceeded this biomass level in 70.6% of Great Plains lakes and 23.3% of Eastern Temperate Forests lakes, but 0% of Northern Forests lakes. Using model selection analysis, we showed that carp was a key driver of plant species richness along with Secchi depth, lake area and human development of lake watersheds. Model parameters showed that carp reduced species richness to a similar degree across lakes of various Secchi depths and surface areas. In regions dominated by carp (e.g., Great Plains), carp had a stronger impact on plant richness than human watershed development. Overall, our analysis shows that the introduction of common carp played a key role in driving a severe reduction in plant cover and richness in a majority of Great Plains lakes and a large portion of Eastern Temperate Forests lakes in North America.  相似文献   

8.
浅水湖泊牛山湖和月湖均位于长江中游武汉市境内,前者水质清澈、沉水植物茂盛,属典型的草型湖泊;后者长期受生活污水和工业废水排放的影响,水质恶劣、沉水植物稀少,属典型的藻型湖泊。文章选择这两个湖泊的共同优势鱼类——鲫(Carassius auratus)作为研究对象,通过比较两类不同湖泊环境条件下鲫种群结构和生长上的差异,评估人类活动引起的水环境改变对鱼类种群生存状况的影响。2006年春季(3—5月),于牛山湖和月湖各采集鲫种群样本713尾和641尾,研究结果表明:(1)牛山湖和月湖鲫种群的全长频数分布经kolmogorov-Smirnov检验均符合正态分布,但前者的分布范围(63—271 mm)大于后者(72—191 mm),前者的全长峰值(190 mm)亦大于后者(110 mm);(2)牛山湖鲫种群的年龄组成(6个年龄组)较月湖(仅3个年龄组)完整,但月湖各龄鲫的全长均显著大于牛山湖(P<0.05);(3)两个湖泊性成熟鲫的雌、雄鱼比均随全长的增长而增加,即小个体性成熟鲫以雄鱼为主,大个体性成熟鲫以雌鱼为主,该现象在月湖更为明显;(4)牛山湖和月湖鲫全长–体重回归关系(W=a Lb)分别为W=0.00001 L3.060(R2=0.989)和W=0.000006 L3.246(R2=0.971),协方差分析表明两个湖泊鲫种群的b值差异极显著(P<0.01);另一方面,月湖鲫种群各全长组雌、雄鱼的肥满度均显著大于牛山湖(P<0.05)。作者认为影响牛山湖和月湖鲫生长和种群结构的主要因素是两个湖泊饵料组成和捕捞压力等方面的差异。  相似文献   

9.
长江中下游鲢鳙草青四大家鱼线粒体DNA多样性分析   总被引:74,自引:2,他引:74  
对长江中、下游湖北石首、江西九江、安徽芜湖三江段鲢、鳙、草鱼、青鱼天然群体共365尾鱼的线粒体DNA(mtDNA)的ND5/6、Cytb基因和D-Loop区片段进行了限制性内切酶酶切片段长度多态(RFLP)分析。结果表明:(1)长江中、下游鲢、鳙和青鱼的遗传多样性丰富,草鱼不甚丰富。发现鲢、鳙和青鱼的mtDNA基因型分别有28、19、27种,草鱼mtDNA基因型仅见7种;鲢、鳙和青鱼的基因型多样性  相似文献   

10.
1. We conducted enclosure experiments in a shallow eutrophic lake, in which a biomass gradient of the filter-feeding planktivore, silver carp, Hypophthalmichthys molitrix Valenciennes, was created, and subsequent community changes in both zooplankton and phytoplankton were examined.
2. During a summer experiment, a bloom of Anabaena flos-aquae developed (≈ 8000 cells mL−1) solely in an enclosure without silver carp. Concurrent with, or slightly preceding the Anabaena bloom, the number of rotifer species and their abundance increased from seven to twelve species (1700–14 400 organisms L−1) after the bloom in this fish-free enclosure. Protozoans and bacteria were generally insensitive to the gradient of silver carp biomass.
3. During an autumn experiment, on the other hand, large herbivorous crustaceans were more efficient than silver carp in suppressing the algae, partly because the lower water temperature (≈ 24 °C) inhibited active feeding of this warm-water fish and also formation of algal colonies. Heterotrophic nanoflagellate and bacterial densities were also influenced negatively by the crustaceans.
4. Correspondence analysis (CA) was applied to the weekly community data of zooplankton and phytoplankton. A major effect detected in the zooplankton community was the presence/absence of silver carp rather than the biomass of silver carp, whereas that in the phytoplankton community was the fish biomass before the Anabaena bloom, but shifted to the presence/absence of the fish after the bloom.  相似文献   

11.
Forty‐four microsatellite DNA markers were developed for silver carp, and used to investigate polymorphisms of 41 wild silver carps and seven wild bighead carps collected from Jingzhou fragment of Yangtze River. In silver carp, 40 markers were polymorphic. A total of 297 alleles were detected at 40 polymorphic loci. The number of alleles per locus varied from two to 16 with an average of 7.4 and the expected heterozygosities of each locus ranged from 0.07 to 0.91 with an average of 0.69. All markers amplified both silver carp and bighead carp DNAs.  相似文献   

12.
不同日照时数对鲤,鲢,鳙鱼苗生长和存活的影响   总被引:4,自引:0,他引:4  
不同日照时数对鲤、鲢、鳙鱼苗生长和存活的影响王吉桥,赵德树,张景全(大连水产学院养殖系,116023)(大连市碧流河水库渔场,116428)EffectofPholoperiodontheGrowthandSurvivalofSilverCarp,B...  相似文献   

13.
草鱼出血病病毒对其它鱼的感染性研究   总被引:3,自引:0,他引:3  
用草鱼出血病病鱼分离出的草鱼出血病病毒(Grass carp hemorrhage virus,GCHV)感染其它常见鱼并用ELISA方法检查感染鱼组织提取液,结果表明:青鱼、鲢鱼、布氏鳌条对GCHV抗体呈阳性反应;鲤鱼、鳙鱼、鲫鱼、团头鲂、泥鳅则呈阴性反应。综合感染鱼发病症状及死亡特征,初步认为:青鱼对GCHV是易感的,GCHV能在鲢鱼、布氏蟹条体内增值,但毒力较低,鳙鱼、鲫鱼、团头鲂、鲤鱼、泥鳅能抗GCHV感染。  相似文献   

14.
青草鲢鳙四种鱼同工酶的比较研究   总被引:16,自引:0,他引:16  
姜建国  熊全Wei 《遗传》1998,20(2):19-22
采用聚丙烯酰氨垂直板状连续电泳方法,对青草鲢鳙6种组织、10种同工酶和蛋白质进行了电泳研究,并结合作者以前做的工作,对所研究的共21种同工酶和蛋白质在4种鱼中的组织分布,位点表达及活性作了分析和总结。结果表明:4种鱼同工酶的种内组织分布差异大于种间差异;ADH、AMY、CAT、EST、ME、POX、SDH存在不同程度的种间差异,可作为种类的遗传标记;4种鱼MDH、GOT、ALP、AO、SOD同工酶谱非常相似,只在活性上略有差异;LDH、G6PDH和COX的酶谱特征可作为青草和鲢鳙两个亚科的鉴别标记。  相似文献   

15.
传统稻鱼系统中“田鲤鱼”的形态特征   总被引:1,自引:0,他引:1  
稻田养鱼是一种重要的传统农业系统,养殖在稻田中的鲤鱼,在长期的自然选择和人工选择下逐渐形成了适应于稻田浅水环境的“田鲤鱼”.本研究以具有千年历史的全球重要农业文化遗产系统“青田稻鱼共生系统”和“从江稻鱼鸭系统”的青田田鱼和从江田鱼为范例,通过采样对两种“田鲤鱼”进行传统形态学分析和地标几何形态学分析;采用线粒体基因构建系统发育树;通过数据库数据提取和采样测量对两种“田鲤鱼”和其他常见鲤鱼种群或品系进行传统形态学聚类分析.传统形态学分析和地标几何形态学分析表明,青田田鱼和从江田鱼在形态上存在差异,与青田田鱼相比,从江田鱼尾部长而窄,体型较细长,尾部长度占身体长度比例小.对这两种田鱼及养殖于其他水体的其他鲤鱼种群进行系统发育树分析表明,青田田鱼和从江田鱼在遗传上是独立的种群;但形态聚类分析表明,这两种田鱼归为一类,明显不同于其他鲤鱼种群或品系,与其他鲤鱼种群的差异主要表现在背鳍和尾鳍上.这些研究结果说明,长期生活在稻田环境的青田田鱼和从江田鱼在遗传和形态上均明显不同于其他水体养殖鲤鱼种群,且青田田鱼和从江田鱼之间形态上存在差异.  相似文献   

16.
Silver carp and bighead carp exhibited size-selection for food particles in aquarium experiments, but did not select their preferred species of plankton actively when they were distributed evenly in the water. They also possessed the capacity of selection for feeding area. The removal rates (% g−1 fish weight) of silver carp for smaller plankton (phytoplankton) were higher than those of bighead carp. The removal rates by the latter for bigger plankton (zooplankton) were higher than those of silver carp, but for plankton about 70 μm dia. the rates by the two species were almost equal.  相似文献   

17.
采用组织块移植培养技术,分别用DMEM和RPM11640培养基对青海湖裸鲤肝胰组织细胞进行原代培养。培养48h组织块周围有细胞迁出,并形成生长晕。培养一周可形成单层细胞。对原代培养的单层细胞用胰蛋白酶-EDTA消化后,传代培养至第四代。确立青海湖裸鲤肝胰细胞培养条件为:培养基为DMEM,培养温度为27℃,pH值为7.0—7.5,原代培养血清浓度为20%,传代培养的血清浓度为10%,无需通入CO2和添加细胞生长因子。  相似文献   

18.
线粒体控制区在鱼类种内遗传分化中的意义   总被引:14,自引:0,他引:14  
线粒体DNA(mtDNA)作为分子标记已被广泛应用于各物种系统发生的研究。mtDNA控制区序列(D-Loop)以其较高的突变积累对于研究物种种内的遗传分化具有重要价值。鱼类是脊椎动物中最原始但在种属数量上又最占优势的类群,其物种繁多,分布广泛,起源复杂,研究其系统发生历来是令人饶有兴趣的课题。D-Loop在研究鱼类种内遗传分化中具有多方面的重要意义。近年来,已有越来越多的研究工作将D-Loop作为分子标记来探讨各种鱼类的种内遗传分化,并且获得了许多有启发性的结果。青海湖是我国内陆最大的咸水湖,湖中主要鱼类为青海湖裸鲤(Gymnocypris przewalskii),D-Loop分析初步结果显示青海湖及其周围河流中的裸鲤似乎没有新的种内遗传分化现象。   相似文献   

19.
20.
长江水系钱草鱼遗传结构及变异性的RAPD研究   总被引:34,自引:10,他引:34  
采用随机扩增多态性DNA(RAPD)技术对长江中游的湖北嘉鱼与江西瑞昌两个地理群体和中游的汉江和湘江两大水系的鲢和草鱼的群体进行了遗传学研究。发现长江水系链的遗传变异要高于草鱼,与现今生物量成反比的反常现象。鲢遗传多样性从大到小的分布是嘉鱼→湘江→瑞昌→汉江。草鱼遗传多样性从大到小的分布是瑞昌→汉江→湘江→嘉鱼,鲢和草鱼的遗传多样性地理分布并不一致。遗传分化指数Gst分别为12.3%和17.5%,表明鲢和草鱼的四个地理群体的遗传分化度较低,可能与地理较近和基因交流频繁有关。  相似文献   

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