The Community Structure Of Phytoplankton Of Marine Higher-place Ponds Cultivating Litopenaeus Vannamei In Jinzhou

The reasonable water quality in the ponds is very important for the growth of the Litopenaeus vannamei Boone,1931.Plankton play a vital role in material circulation,energy flowing and information delivery in the water ecosystem,they are the indicator of environment because they have very close relationship with water quality.In order to improve the feasibility of large-scale cultiviting L.vannamei through higher-level ponds in north china..This experiment studied the changes of plankton structure and the indexes of water quality of the higher-level ponds which is high salinity that cultivating L.vannamei in Jinzhou in 2015 and 2016,analyzed the relationship between the dominant species of plankton and water quality.The results showed that,the water temperature in 2015 and 2016 were 26.8 and 27.2? ?,The pH were 8.16 and 8.67.The salinity were 23.0 and 20.3.The main species of phytoplanktons in 2015 were Bacillariophyta,Euglenophyta,Chlorophyta,which accounted for 39.58%,20.83% and 18.75 %,besides,some species of Pyrrophyta,Cyanophyta and Cryptophyta were also appeared in the higher-level ponds.The main species of phytoplanktons in 2016 were Bacillariophyta,Pyrrophyta,Chlorophyta,which accounted for 58.82%,17.65% and 11.76 %,besides,some species of Euglenophyta and Cyanophyta were also appeared in the higher-level ponds.The phytoplankton density in 2015 and 2016 were 1.11×108 cells·L^-1 and 6.22×1010 cells·L^-1,The phytoplankton biomass were 22.39 mg·L^-1 and 18.81 mg·L^-1.The shannon-weiner indexes?H??of phytoplanktons in 2015 and 2016 were 0.58 and 2.08,the evenness indexes?J?were 0.16 and 0.73.The zooplankton density in 2015 and 2016 were 24.72 ind·L^-1 and 62.26 ind·L^-1,the zooplankton biomass were 0.56 mg·L^-1 and 0.46 mg·L^-1.The shannon-weiner indexes?H??of zooplanktons in 2015 and 2016 were 0.68 and 1.43,the evenness indexes?J?were 0.52 and 0.73.According to the results of CCA/RDA,the main factors that affecting the dominant phytoplanktons in 2015 were TN,S,PO43--P;the main factors that affecting the dominant phytoplanktons in 2016 were TH,the main factors that affecting the dominant zooplanktons in 2015 were S,NO₂^--N,the main factors that affecting the dominant zooplanktons in 2016 were NH₄⁺-N.The experiment showed that,cultiviting L.vannamei through higher-level ponds in north china is feasible if the conditions,such as larvae,water quality,feed are all good.