Study On Fishery Community Structure Characteristics And Niche In Zhoushan Coastal Fishing Ground

We studied the fishery community and species biodiversity by performing a survey of the bottom-trawling fishery resources in Zhoushan coastal fishing ground in November 2015 and May 2016.we studied the species composition,dominant species,resource density,biological diversity,similarity community structure,ecological niche and interspecific association of fishery by used relative importance index,biodiversity index,hierarchical cluster,non-metric multidimensional scaling(nMDS)analyses,abundance-biomass comparison curve(ABC curve),inter-species coupling measure and so on.The results were as follows:(1)A total of 130 species of fishery were identified,belonging to 99 genera in 62families of 17 order.There are 81 fish species belonging to 63 genera in 39 families of12 order,21 shrimp species belonging to 15 genera in 8 families of one order,20 crab species belonging to 15 genera in 11 families of one order,one mantis shrimp species and 7 cephalopods species belonging to 5 genera in 3 families of 3 order.The number of species is 88 in spring and 95 in autumn.The number of fishery species was higher in autumn than in spring.Dominant species in the spring were Amblychaeturichthys hexanema,Acetes chinensis,Exopalaemon annandalei and Collichthys lucidus.Dominant species in the autumn were Harpodon nehereus,Exopalaemon annandalei and Portunus trituberculatus.According to hierarchical cluster and non-metric multidimensional scaling(nMDS)analyses,the fishery can be divided into 4communities in spring,and it can be divided into 3 communities in autumn.And the similarity of community in autumn was higher than that in spring.The Shannon-Wiener diversity index,the Pielou’s evenness index and the species richness index were higher in the spring than in the autumn.The abundance-biomass comparison curve(ABC curve)showed that the fishery communities in the survey area were unstable and disturbed.(2)The species whose relative importance index of fishery resources in the survey area is greater than 100 are selected as the important fishery resources to study their niche and interspecific association.Based on the niche breadth cluster analysis,the important fishery can be divided into three groups.They were wide niche breadth species,moderate niche breath species and narrow niche breath species.The niche overlap value of them ranged from 0 to 0.99,indicating that these species were of great similarity in resource utilization,and there was a certain degree of competition between them.The values of VR and W indicated that there was significantly positive correlation between the communities of the main fishery.TheΧ~2-test suggested that there was significantly interspecific association for 31 species pair(Χ~2≥3.841).The results of IO and JI index revealed that the association of interspecific was strong.