| Shuangpai Reservoir is located at the lower reachers of Xiaoshui River,the main branch of Xiangjiang River.The exact location of the reservoir,which chiefly functions in irrigation combined with power-generating,transportation and flood control, is the village called Zhouchong at the upper reachers,Hupo town(ever called Chengguan town),Shuangpai county,Yongzhou city.Shuangpai Reservoir is one of the two biggest reservoirs.Its existence is the comprehensive development as well as utilization of water resources.It plays an important role in utilizing the advantages of the water resources in this city,solving the drought and flood problems as well as in the development of the agriculture and industry production and the improvement of the life level of our people.In this thesis,the author aims at the discussing and exploring the way of development and utilization the fishery ecological resources of Shuangpai Reservoir through investigating the natural water conditions of Shuangpai Reservoir, surveying and analyzing the chemical factors of the reservoir,as well as the surveying of the circumstances of the aquatic life and the fishery resources of Shuangpai Reservoir.There are ten years in which the average temperature of the reservoir is above 18℃. The average temperature of the water is 20.9℃.The change range of the transparency is 1.9~2.8m,and the average value is 2.37m.The difference of the transparency,among the upper reachers,the middle reachers and the lower reachers,is unobvious.The soils of the reservoir area are mainly red soil and yellow soil.Then its salinity saturation degree is low,accordingly the microorganism mineralization is rapid.The very high rainfall causes the severe eluviations.The average pH value is 6.87,and the change range of the pH value of the whole reservoir waters is between 6.74~7.13.The reservoir water quality is inclining to acidity or approaching neutral.The water in the reservoir is rich in stable and well-distributed oxygen.The average dissolved oxygen value is 9.15mg/L,and the vertical distribution has little obvious difference from the upper reachers to the lower reachers,with the change range of 8.95~9.26mg/L.The dissolved oxygen are generally in the state of saturated or over-saturated.The dissolved oxygen value of the upper and the middle layer is a little higher than the lower layer; however,it can also arrived at 3.0mg/L on the lower layer.Moreover it varies little from day to night as well as at the vertical level.The general hardness of the water of Shuangpai Reservoir is 1.20mmol/L.The general basicity is 1.11mmol/L.The calcium content and the magnesium contents are respectively 21.64mg/L and 2.16mg/L.The content of nitrogen in nitroso state,nitrogen in ammonium state and the phosphate are relatively lower,the average value of which are respectively 0.0052mg/L,0.035mg/L,0.0038mg/L.The value of the oxygen consuming by the organic substance is 2.33mg/L,with the little change though unobvious.Sixteen genera of five phyla phytoplankton,totaled 854.9thousand/L,are founded in Shuangpai Reservoir.Among them,Chlorophyta has an absolute advantage in the term of quantity,next Bacillariophyta,Cyanophyta,Chrysophyta and Pyrrophyta,and their percentages are respectively 50.74%,32.55%,11.55%,3.33%and 1.83%.The biology amount gained from the four times sampling of the phytoplankton is 0.785mg/L, the relatively smaller quantity shows that the water quality is of the kind of nutrition inadequate.As to the content of the biology amount,Bacillariophyta,Chlorophyta, Pyrrophyta,Chrysophyta and Cyanophyta take the percentage of 51.33%,24.46%, 22.17%,1.4%,0.64%respectively.There are obvious changes in the process of season alternation:in the spring,Bacillariophyta take the percentage of 53.72%,then is Chlorophyta 25.94%;in summer,the percentage of Pyrrophyta is 33.76%, Bacillariophyta take the second place of 29.58%;in autumn,Chlorophyta 37.65%,the next is Bacillariophyta 26.91%,Pyrrophyta 21.37%.What's more,the predominant groups of the biology amount also show evident alternation:in the spring,the predominant groups are Cyclotella and tabellaria;in summer,it is mainly Pyrrophyta; in autumn,they are Cosmarium and Oocystis,while in winter,due to the nadir value, the predominant group is not so obvious.The average zooplankton amount of Shuangpai Reservoir is 1.126mg/L,mostly including rotifer,Cladocera,Copepoda and Protozoa.In the aspect of quantity,rotifers take the percentage of 16.53%;Cladocera 17.06%,Copepoda 8.85%and the Protozoa 57.56%;in the aspect of biology amount,rotifers take the percentage of 6.39%, Cladocera 76.82%,Copepoda 16.61%and the Protozoa 0.18%.The change of the biology amount of the zooplankton along with the season alternation follows the rule: the amount is bigger in autumn than in summer;in summer it is bigger than in spring; and in spring its amount is bigger than in winter.The smallest amount of the biology turns up in January or February,while the biggest arise in summer or autumn.The biology amount gained from the four times sampling of the benthos is 2.87g/m~2,and the exact quantity is 1213.8个/m~2.The biology amount and quantity of the bottom-dwelling creature at the lower reachers is much bigger than at the upper reachers.,among which,Chironomide larva take the percentage of 91.75%,water earthworm 8.25%,and no clam and snail have been found.The individual of the Chironomide larva and water earthworm are very small,among about 10~65mm in length,most of them have the length of 15~35mm.According to the category component,distribution,rate of coverage as well as the appearance frequency in the water space,we can find that Shuangpai Reservoir's hydrophytes community consists of Wolffia arrhiza,Vallisneria spiralis,Najas minor, Nelumbo nucifera,Heleocharis dulcis,Azolla imbricate,Trapanatans var.bispinosa, Scirpus triangulates,Ceratophyllum demersum,Eichhornia crassipes,phragmitis communis,Hydrilla varticillata,Alternanthera pHiloxeroides,Potamogeton malainus, Sagittaria sagittifolia var.sinensis,Saluinia natans,NympHaea tetragona and Ottelia alismoides.The fish community of Shuangpai Reservoir consists of Hypophthalimichthys molitrix,Aristichthys nobilis,Cyprinus carpio,Carassius auratus,Megalobrama amblycepHala,Ctenopharyngodon idellus,Mylopharyngodon piceus,Cirrhinus molitorella,Xenocypris argentea,Distoechodon turmirostris,parasilurus asotus, Siniperca chuatsi,OpHiocepHalus argus,Pseudolaubuca sinensis,Pseudobagrus fulvidraco and pseudorasbora parva. |
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