Correlation Between Plankton Community Structure And Environmental Factors And The Distribution Of Acetes Chinensis Yield In Haizhou Bay In Summer

In this study,a plankton sampling survey was conducted from June 15 to July 15in 2021 and 2022,during the implement quota fishing measures for Acetes chinensis.with 6 stations designed in 2021 and 31 stations in 2022.The spatial differences in biology parameters were analyzed in detail during the survey period,while relevant environmental factors were collected in 2022 to understand the relationship between the changes in plankton community structure and environmental factors through statistical analysis and finally,the correlation between plankton and A.chinensis in Haizhou Bay was initially speculated by combining the distribution of A.chinensis resources in Haizhou Bay.To provide basic data for the protection of the living habit of A.chinensis in the coastal area of Haizhou Bay,and to provide a scientific basis for the rational exploitation and control of biological resources in the area.The main results of the study are as follows:1.By collecting a large number of Acetes chinensis in Haizhou Bay,and the use of traditional morphology of their species identification,tentatively determined that the sea A.chinensis.2.In 2021,a total of 43 species of phytoplankton from 7 phyla were identified in the coastal area of Haizhou Bay.Among them,Bacillariophyta had the largest number of species,with 15 species,accounting for 35%of the total number of species;Chlorophyta came second,with 12 species,accounting for 28%of the total number of species;Cyanophyta had 7 species,accounting for 16%of the total number of species;the Pyrroptata and Euglenophyta had 3 species each,the Xanthophyta had 2 species and Chysophyta had 1 species,accounting for 21%of the total number of species.The abundance of phytoplankton ranged from 41,775.00×10~4cells/m~3to 168,850.00×10~4cells/m~3,with an average abundance of 76,183.33×10~4 cells/m~3,with Bacillariophyta being the most dominant.In 2022,a total of 57 species of phytoplankton from 5 phyla were identified in the coastal area of Haizhou Bay.Among them,Bacillariophyta had the largest number of species,with 48 species identified,accounting for 84%of the total number of species;5 species of the Pyrroptata,2 species of Cyanophyta,and one species each of Chysophyta and Chlorophyta,accounting for 16%of the total number of species.The abundance of phytoplankton ranged from 50.00×10~4cells/m~3to 950.00×10~4 cells/m~3,with an average abundance of 435.49×10~4 cells/m~3,and Bacillariophyta was dominant.Combined with the 2022 environmental factors,the canonical analysis(CCA)showed that the main environmental factors affecting the abundance and distribution of phytoplankton in Haizhou Bay and its adjacent waters were surface salinity,surface water temperature,and water depth in order,especially the abundance and distribution of some major phytoplankton in this survey were closely related to the above environmental factors.3.In 2021,a total of 23 species of zooplankton from six categories were identified in the coastal waters of Haizhou Bay.Copepods were the most abundant species,with13 species,accounting for 57%of the total number of species;Pelagic larvae were the second most abundant species,with 4 species,accounting for 17%of the total number of species;medusae and Cladocera were each two species,and protozoa and Chaetognatha were each one species,accounting for 26%of the total number of species.The abundance of zooplankton ranged from 162.83 ind./m~3to 973.21 ind./m~3,with an average abundance of 562.38 ind./m~3.In 2022,a total of 36 species of zooplankton in six categories were identified in the inshore waters of Haizhou Bay.There were 20 species of copepods,accounting for56%of the total number of species,followed by 7 species of Pelagic larvae,accounting for 19%of the total number of species,5 species of medusae,accounting for 14%of the total number of species,2 species of Cladocera,1 species of protozoa and 1 species of Chaetognatha,accounting for 11%of the total number of species.The abundance of zooplankton ranged from 249.49 ind./m~3to 7221.09 ind./m~3,with an average abundance of 2623.94 ind./m~3.Combined with the environmental factors in 2022,the redundancy analysis(RDA)showed that the main environmental factors affecting the abundance and distribution of zooplankton in Haizhou Bay and its adjacent waters were surface salinity,water depth,silica and phosphorus in that order.In particular,the abundance and distribution of some dominant zooplankton species are closely related to these environmental factors.4.The close correlation between A.chinensis population density and phytoplankton abundance may be because,since A.chinensis feed on phytoplankton,especially Bacillariophyta,and thus A.chinensis population density and phytoplankton abundance are correlated;and small and medium-sized zooplankton abundance are mutually exclusive,probably due to a competitive feeding relationship between the two.The trends in phytoplankton and zooplankton communities differed at small spatial scales from previous studies in other waters of Haizhou Bay.This study showed that there was a high overlap between the high phytoplankton abundance areas and the high prawn production areas,while the correlation between zooplankton abundance and prawn production was not significant and the spatial distribution of the two did not overlap,which may be due to phytoplankton feeding by prawn and food competition between prawn and the dominant zooplankton species,Calanus sinicus.The plankton survey and analysis in this study will help to provide basic data on the survival environment of A.chinensis and to achieve spatial prediction of the A.chinensis fishery and sustainable use of its resources in China.