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1.
《中国海洋湖沼学报》2016,(1)
Dam construction alters natural flow regimes which,in turn,cause significant changes in fish communities during and after impoundment. The construction of the Three Gorges Reservoir,from impoundment of the Changjiang(Yangtze) River,China,may have affected native fish species. Thus,the status of two lotic freshwater fish species,Coreius heterodon and C.guichenoti,were monitored in the Three Gorges Reservoir,including fish abundance,individual composition,growth,condition,and mortality. Data on both species were gathered from upstream,midstream and downstream areas of the reservoir and,where available,from studies published before and after dam construction. Lower abundance,slower growth,a less diversified age structure,poorer fish condition(indicated by hepatosomatic index) and higher mortalities were recorded in sites nearest the dam compared with upstream areas. Furthermore,after final impoundment,individual Coreius species inhabiting the area changed,with young individuals becoming more abundant,while upstream of the reservoir the two Coreius species became smaller at a given age. The results show that the status of the two Coreius species was subject to dramatic changes after impoundment. 相似文献
2.
报道了鲢、鳙鱼溶血性腹水病的病原和防治方法。研究结果表明，该病无病毒性病原存在，病原为嗜水气单胞菌嗜水亚种（Aeromonashydrophilasubsp.hydrophila）。采用作者研制的鱼康乐（Y·K·L）进行治疗。治愈率达86．5‰。 相似文献
3.
ＩＮＴＲＯＤＵＣＴＩＯＮＭｉｃｒｏｃｙｓｔｉｓａｅｒｕｇｉｎｏｓａｗａｓｔｈｅｍａｉｎｂｌｏｏｍ ｆｏｒｍｉｎｇｓｐｅｃｉｅｓｉｎＤｏｎｇｈｕＬａｋｅ;ｏｃｃｕｒｒｅｄｏｎｌｙｓｐｏｒａｄｉｃａｌｌｙｉｎｔｈｅ 1 950ｓ,ｉｎｃｒｅａｓｅｄｒａｐｉｄｌｙｉｎｎｕｍｂｅｒｉｎｔｈｅ 1 960ｓ.Ｆｒｏｍｔｈｅｍｉｄｄｌｅｏｆｔｈｅ 1 970ｓｔｏｔｈｅｍｉｄｄｌｅｏｆｔｈｅ 1 980ｓ,ｔｈｉｃｋｌａｙｅｒｏｆｉｔｓｂｌｏｏｍｃｏｖｅｒｅｄｔｈｅｌａｋｅｓｕｒｆａｃｅｅｖｅｒｙｓｕｍｍｅｒ,ａｔｔｒａｃｔ ｉｎｇｆｏ… 相似文献
4.
长江下游江段铜鱼肌肉营养成分分析 总被引：7，自引：0，他引：7
对采自长江下游江段的铜鱼(Coreius heterodom)肌肉营养成分进行了测定和分析。结果表明,铜鱼肌肉水分、粗蛋白质、粗脂肪和粗灰分占鲜样的比例分别为:70.03%、20.54%、6.82%和1.38%;按照氨基酸评分(Amino Acid Score,AAS)和化学评分(Chemical Score,CS)标准,铜鱼限制性氨基酸为缬氨酸和异亮氨酸,必需氨基酸指数(EAAI)为81.52;不饱和脂肪酸和ω-3多不饱和脂肪酸含量分别为63.03%和2.0%;肌肉中常、微量元素含量最高分别为钾(3135μg/g)和铁(5.46μg/g),锌铜比和锌铁比分别为8.85和0.65。 相似文献
5.
We characterized variations in bacterioplankton community composition(BCC) in mesocosms subject to three different treatments. Two groups contained fish(group one: Cyprinus carpio; group two: Hypophthalmichthys molitrix); and group three, the untreated mesocosm, was the control. Samples were taken seven times over a 49-d period, and BCC was analyzed by PCR-denaturing gradient gel electrophoresis(DGGE) and real-time quantitative PCR(q PCR). Results revealed that introduction of C. carpio and H. molitrix had a remarkable impact on the composition of bacterioplankton communities, and the BCC was significantly diff erent between each treatment. Sequencing of DGGE bands revealed that the bacterioplankton community in the different treatment groups was consistent at a taxonomic level, but differed in its abundance. H. molitrix promoted the richness of Alphaproteobacteria and Actinobacteria, while more bands affiliated to Cyanobacteria were detected in C. carpio mesocosms. The redundancy analysis(RDA) result demonstrated that the BCC was closely related to the bottom-up(total phosphorus, chlorophyll a, phytoplankton biomass) and top-down forces(biomass of copepods and cladocera) in C. carpio and control mesocosms, respectively. We found no evidence for top-down regulation of BCC by zooplankton in H. molitrix mesocosms, while grazing by protozoa(heterotrophic nanoflagellates, ciliates) became the major way to regulate BCC. Total bacterioplankton abundances were significantly higher in C. carpio mesocosms because of high nutrient concentration and suspended solids. Our study provided insights into the relationship between fish and bacterioplankton at species level, leading to a deep understanding of the function of the microbial loop and the aquatic ecosystem. 相似文献
6.
互花米草是中国东部河口滩涂湿地主要入侵物种之一,其与本地物种芦苇竞争生长,形成了大范围的混合交错带。该交错带是研究湿地生态系统动态变化的重要信息,但因2种物种光谱的相似性及其在交错带的组成复杂性,使利用遥感技术提取交错带难度较大。因此,本文提出了一种将二者生长物候差异与其光谱特征相结合,考虑二者海陆位置分布差异,运用实测剖面观测数据确定光谱指标和阈值的综合提取方法。运用高分一号多光谱遥感数据,通过分析不同时相互花米草与芦苇冠层光谱差异,确定用来提取混合交错带的高分遥感影像,实现了研究区互花米草-芦苇混合交错带的提取。结果表明：不同时相宜选用不同的提取指标,本研究中在春季选择了近红外波段反射率,而秋季则选择了红波段反射率;2个时相的混合交错带范围存在明显差异,客观反映了互花米草与芦苇在不同季节的竞争状况。 相似文献
7.
The temporal and spatial distributions of zooplankton communities in the upper, middle, and lower reaches of the Xin＇anjiang Reservoir, Zhejiang, China, were investigated monthly, between 2009 and 2010. Silver carp （Hypophthalmichthys moBtrix） and bighead carp （Aristichthys nobilis） dominated the pelagic fish community of this large, deep reservoir. Cladocerans were distributed evenly throughout the reservoir. Rotifers were mainly found in the upper reaches, while copepods tended to assemble in the lower reaches. The Pearson correlation analysis and stepwise multiple regression were used to identify the major physicochemical gradients influencing community variations. Zooplankton community distributions were influenced by water temperature, dissolved oxygen, phosphorus, nitrogen, and silicon. Excess nutrients, in particular silicon, stimulated rotifer growth. Based on these findings, it is possible to use rotifer density as a bioindicator of eutrophic status in deep reservoir ecosystems. 相似文献
8.
Erhai Lake is the second largest freshwater lake on the Yunnan Plateau, Southwest China. In recent decades, a number of exotic fish species have been introduced into the lake and the fish community has changed considerably. We evaluated the status of the fish community based on surveys with multimesh gillnet, trap net, and benthic fyke-net between May 2009 and April 2012. In addition, we evaluated the change in the community using historical data (1952–2010) describing the fish community and fishery harvest. The current fish community is dominated by small-sized fishes, including Pseudorasbora parva, Rhinogobius giurinus, Micropercops swinhonis, Hemiculter leucisculus, and Rhinogobius cliffordpopei. These accounted for 87.7% of the 22 546 total specimens collected. Omnivorous and carnivorous species dominated the community. A canonical correspondence analysis (CCA) plot revealed that the distribution of fishes in the lake is influenced by aquatic plants, water temperature, pH, and season. The abundance of indigenous species has declined sharply, and a majority of endemic species have been extirpated from the lake (a decrease from seven to two species). In contrast, the number of exotic species has increased since the 1960s to a total of 22 at present. The fishery harvest decreased initially following the 1960s, but has since increased due to the introduction of non-native fish and stocking of native fish. The fishery harvest was significantly correlated with total nitrogen, not total phosphorus, during the past 20 years. Based on our results, we discuss recommendations for the restoration and conservation of the fish resources in Erhai Lake. 相似文献
9.
五种鲤科鱼类生长激素cDNA的克隆和序列分析 总被引：1，自引：0，他引：1
通过RT-PCR方法,以草鱼、鳙鱼、鲫鱼、鲤鱼、齐口裂腹鱼等5种鲤科重要经济鱼类的垂体总RNA为模板扩增出其生长激素(fish growth hormone,fGH)的完整ORF序列,并克隆到pMD18-T载体上,命名为pMD-1(草鱼)、pMD-2(鳙鱼)、pMD-3(鲫鱼)、pMD-4(鲤鱼)、pMD-5(齐口裂腹鱼)。测序结果显示,ORF序列其长度均为633 bp。序列分析表明,所有ORF序列均以ATG为起始密码,以TAG为终止密码,编码210个氨基酸残基,推导的生长激素前体由22个氨基酸的信号肽和188个氨基酸的成熟肽组成。同源性分析表明,草鱼、鳙鱼、鲤鱼、鲫鱼和齐口裂腹鱼的fGH同源性在93.3%~99.5%之间。 相似文献
10.
《中国海洋大学学报(英文版)》2019,(6)
Co-occurrence pattern of fish species plays an important role in understanding the spatio-temporal structure and the stability of fish community. Species coexistence may vary with time and space. The co-occurrence patterns of fish species were examined using the C-score under fixed-fixed null model for fish communities in spring and autumn over different years in the Haizhou Bay, China. The results showed that fish assemblages in the whole bay had non-random patterns in spring and autumn over different years. However, the fish co-occurrence patterns were different for the northern and southern fish assemblages in spring and autumn. The northern fish assemblage showed structured pattern, whereas the southern assemblage were randomly assembled in spring. The co-occurrence patterns of fish communities were relatively stable over different years, and the number of significant species pairs in northern assemblage was more than that in the southern assemblage. Environmental heterogeneity played an important role in determining the distributions of fish species that formed significant species pairs, which might affect the co-occurrence patterns of northern and southern assemblages further in the Haizhou Bay. 相似文献
11.
Fish assemblage structure in the hypoxic zone in the Changjiang (Yangtze River) estuary and its adjacent waters were analyzed
based on data from bottom trawl surveys conducted on the R/V Beidou in June, August and October 2006. Four fish assemblages were identified in each survey using two-way indicator species analysis
(TWIA). High fish biomass was found in the northern part, central part and coastal waters of the survey area; in contrast,
high fish diversity was found in the southern part of the survey area and the Changjiang estuary outer waters. Therefore,
it is difficult to maintain high fishery production when high fish diversity is evenly distributed in the fish community.
Fish became smaller and fish size spectra tended to be narrower because of fish species variations and differences in growth
characteristics. Fish diversity increased, the age to maturity was reduced and some migrant species were not collected in
the surveys. Fish with low economic value, small size, simple age structure and low tropic level were predominant in fish
assemblages in the Changjiang estuary and its adjacent waters. The lowest hypoxic value decreased in the Changjiang estuary
and its adjacent waters. 相似文献
12.
Hu Zhaoliang 《中国地理科学(英文版)》1997,8(4):326-334
The seven economic zones are multiple economic zones, with the characteristic of both long-range economic zone and categorical
economic zone. They are the transitional regions between the categorical economic zone and the comprehensive economic zone.
The phenomena of overlapping are only allowed to appear in categorical economic zones. The influence of Hongkong return back
to China should be considered when doing research on economic zones. Hongkong is the center of the southeastern coasts and
will become an offshore banking center of the mainland. According to the theory of economic zoning, the division of the whole
country into seven economic zones demonstrates the transitional nature clearly. With the further development of the economy,
the deeper maturity of the central cities and the stronger connection of the regional economy, the composite economic zones
will gradually turn into more integrated comprehensive economic zones. 相似文献
13.
胡兆量 《中国地理科学(英文版)》1998,8(4):326-334
Ｉ．ＴＨＥＮＡＴＵＲＥＯＦＳＥＶＥＮＥＣＯＮＯＭＩＣＺＯＮＥＳＯｎｍａｒｃｈ１７ｔｈ,１９９６,ｔｈｅｆｏｕｒｔｈｍｅｅｔｉｎｇｏｆｔｈｅＥｉｇｈｔｈＮａｔｉｏｎａｌＰｅｏｐｌｅ’ｓＣｏｎｇｒｅｓｐｕｔｆｏｒｗａｒｄａｐｒｏｐｏｓａｌｏｆｃｏｎｓｔｒ... 相似文献
14.
A Comparative Study of Fish Assemblages Near Aquaculture,Artificial and Natural Habitats 总被引：1，自引：0，他引：1
Habitat plays a critical role in regulating fish community structure. Using the data collected from a monthly trammel net survey in Ma’an archipelago off the east coast of China, we evaluated impacts of five different habitats(artificial reefs, mussel farms, cage aquaculture, rocky reefs and soft bottom) on fish assemblages. This study suggests that artificial reefs(AR) have significantly higher species richness, abundance and diversity than mussel farms(MF) or soft bottom(SB) habitats during most seasons, and that fish taxa in the AR habitats are similar to those in the rocky reef(RR) habitats. Two different fish assemblage patterns were revealed in the study area using non-metric multidimensional scaling ordination: an assemblage dominated by reef fishes(especially by Scorpaenidae species) in AR, RR and cage aquaculture(CA) habitats and an assemblage dominated by Sciaenidae species in MF and SB habitats. We suggest that reef fishes play a key role in differentiating fish community structures in the study area. Although few differences in fish abundance and diversity were found between the CA and SB habitats, a more diverse age structure was observed in the CA habitats. A much more complex fish assemblage and enhanced population of local species were established as a result of the presence of both floating and fixed artificial structures, probably through improved survival rates. 相似文献
15.
Chinese sturgeon (Acipenser sinensis) is the flagship species of the Changjiang River. The migration route of this species is blocked by the first dam, the Gezhou Dam, and its reproduction is affected by the Three Gorges Dam (TGD), one of the largest dams in the world. We studied the impact of the impoundment of the Three Gorges Reservoir (TGR) since 2003 on the spawning stock and the natural reproduction of the Chinese sturgeon by using our monitoring data from 1997 to 2013. Results indicate that TGR impoundment has delayed the first spawning dates of the fish from middle-late October to late November, decreased the amount of spawning activities from twice to only once each year, and significantly reduced egg production. In particular, the fish did not demonstrate any spawning activities in 2013. Therefore, TGR impoundment significantly affects the natural reproduction of the fish downstream of the TGD. The spawning stock size of the fish is also predicted to further decrease in the future, which will lead to a risk of population extinction. Ecological regulations must be imposed on decreasing the water temperature to 20°C before mid-October and increasing water discharge downstream of the TGD in October to induce spawning of the Chinese sturgeon. 相似文献
16.
ZHANG Man SMYTH Rebecca Ashley ZHU Weixia ZHANG Li LI Yuncong WANG Yifan LI Xuejun GU Qianhong GAO Yunni 《中国海洋湖沼学报》2019,(4)
Studies of Daphnia distribution and function could help people manage and protect water quality.We investigated how spatial distribution and filtering efficiency of Daphnia in the transition and lacustrine zones of the Nanwan Reservoir(China).Samplings were conducted seasonally for 2 years from six sites in the reservoir.Daphnia abundance and biomass were significantly higher in the lacustrine zone than in the transition zone.Similar composition and biomass of edible phytoplankton were found in the two zones,suggesting that food quantity could not explain high Daphnia distribution in the lacustrine zone.The variations of water velocity and food quality could help explaining Daphnia patchy distribution in the reservoir.On the one hand,rapid water velocity can cause the Daphnia decrement in the transition zone.On the other hand,the ratio of particulate organic carbon(POC)to chlorophyll a(chl a)concentration was significantly higher in the transition zone,indicating more allochthonous material constituted the food source for Daphnia.The lower quality food likely suppressed Daphnia development in the transition zone.A linear regression between Daphnia abundance and Secchi depth(SD)may suggest a cause-effect relationship where increased filtering efficiency was responsible for increased water clarity to some extent. 相似文献
17.
Tintinnid ciliates are important pelagic microplankton.Most studies previously conducted in the Amundsen Sea have covered a relatively small latitude range and provided minimal information about tintinnid species composition and distribution.The present study was conducted to investigate tintinnid assemblages from the Antarctic zone(AZ)northward through the polar front(PF)to the subantarctic zone(SAZ).A total of 17 tintinnid species belonging to seven genera were collected,and 16 were identified.Results show that nine of the species are endemic to the Southern Ocean and they mainly inhabit the AZ near Antarctic continent with an abundant proportion exceeding 60%of total tintinnid.According to the tintinnid abundance distribution,the species were divided into four groups:Group I includes Acanthostomella norvegica,Codonellopsis glacialis,C.pusilla and Cymatocylis antarctica and mainly occurs in the northern boundary of the PF;Group II includes Cymatocylis convallaria forma calyciformis,an unidentified species,and Amphorellopsis quinquealata and mainly inhabits the PF;Group III includes Salpingella costata,Cymatocylis vanhoeffeni,C.convallaria forma cristallina,C.convallaria forma drygalskii,C.convallaria,Codonellopsis gaussi,and Laackmanniella naviculaefera and mainly occurs in the AZ near the Antarctic continent;and Group IV,which comprises Salpingella sp.and inhabits all zones.The new species of tintinnid(belonging to Group II)primarily inhabit the AZ but also are distributed in the PF,and they have large lorica-oral-diameter(LOD).The distribution ranges of tintinnid assemblages from the AZ to PF were determined,in addition to the different assemblages mixed in the PF.The information provided in this study increases our understanding of tintinnid assemblages from the Antarctic continent in the Antarctic Circumpolar Current and Antarctic waters. 相似文献
18.
Microcystis bloom, one of the most objectionable characteristics of eutrophication in tropical and subtropical waters, occurred in Donghu Lake (East lake) of Wuhan every summer from the 1970s up to 1984, but from 1985 up to now failed to occur there. The cause of its disappearance rema-ined in obscurity until recently. In situ enclosure experiments in the lake for three years showed that the stocking of the filter-feeding silver carp ( Hypophthalmichthys molitrix ) and big-head carp (Aristichthys nobilis ) played a decisive role in eliminating Microcystis bloom from the lake; but that recurrence of the bloom is possible under certain conditions. This paper presents the details and the results of enclosure ex-periments. The authors‘ analysis of fish biomass data obtained by echo-sounding and the fishery produc-tion of the lake over the years, revealed that the recurrence of Microcystis bloom can be prevented so long as the combined biomnss of silver carp and big-head carp remains at or exceeds 50 g per cubic meter of lakewater, as was the case in the lake‘s 1985 fish yield of 1015 t. 相似文献
19.
Status of two <Emphasis Type="Italic">Coreius</Emphasis> species in the Three Gorges Reservoir,China
Dam construction alters natural flow regimes which, in turn, cause significant changes in fish communities during and after impoundment. The construction of the Three Gorges Reservoir, from impoundment of the Changjiang (Yangtze) River, China, may have affected native fish species. Thus, the status of two lotic freshwater fish species, Coreius heterodon and C. guichenoti, were monitored in the Three Gorges Reservoir, including fish abundance, individual composition, growth, condition, and mortality. Data on both species were gathered from upstream, midstream and downstream areas of the reservoir and, where available, from studies published before and after dam construction. Lower abundance, slower growth, a less diversified age structure, poorer fish condition (indicated by hepatosomatic index) and higher mortalities were recorded in sites nearest the dam compared with upstream areas. Furthermore, after final impoundment, individual Coreius species inhabiting the area changed, with young individuals becoming more abundant, while upstream of the reservoir the two Coreius species became smaller at a given age. The results show that the status of the two Coreius species was subject to dramatic changes after impoundment. 相似文献
20.
《中国海洋湖沼学报》2021,(5)
Although intestinal fungi play important roles in host health and disease,the composition and diversity of fungal communities remain poorly reported in fish.In this study,fungi in the fore-,mid-,and hindintestine of tilapia(Oreochromis mossambicus) and bighead carp(Aristichthys nobilis) from Hongchaojiang Reservoir in Guangxi,China were investigated by ITS sequencing.Based on this,we obtained 1 763 478 high-quality tags,which clustered into 1 089 operational taxonomic units(OTUs).In total,404 OTUs were annotated,of which 310,68,and 26 belonged to Ascomycota,Basidiomycota,and other,respectively.Results show significant differences in the community composition of intestinal fungi between tilapia and bighead carp but not within their different intestinal segments.Furthermore,154 of the 404 annotated OTUs were considered reliable and were classified into three trophic modes and nine guilds.The three trophic modes consisted of 108 OTUs of saprotrophic fungi,41 OTUs of pathotrophic fungi,and five OTUs of symbiotrophic fungi.The top three most abundant OTUs overall(i.e.,Otu000002,Scopulariopsis acremonium; Otu000018,Alternaria palandui; Otu000034,Aureobasidium pullulans) showed lower abundance in the hind-intestinal segments of bighead carp,suggesting uneven distribution of these fungi in this species.In addition,saprotrophic and pathotrophic fungi were markedly decreased in the hindintestine.It is indicated that the fungal community was not only related to host species specificity but also to the respective physiological functions of different intestinal segments.These findings provide valuable information on the composition,structure,and potential function of the intestinal fungi community associated with different intestinal segments in tilapia and bighead carp under natural conditions,thus highlighting the importance of fungi as an integral part of the inte stinal microbiota in maintaining host health. 相似文献