Preliminary study on inter annual variations of macrobenthos in Yangshan sea area

Abstract:

According to the results of macrobenthos survey,the inter annual variation of macrobenthic species composition,biomass,density,community diversity and structure are discussed with parameters including Y，C，d，H′，J， by using the method of cluster analysis.The result showed that,in 2003,2004 and 2005,the numbers of benthic species were 21,17 and 16,the biomass were 426g/m2,062g/m2 and 218 g/m2，and the average inhabit densities were 3110 ind/m2,1250 ind/m2 and 1100 ind/m2,respectively.The result indicated that benthic species numbers,biomass,inhabit densities,and diversity indexes were all reducing year by year,while the purity index increased accordingly.Cluster analysis revealed that the results of three surveys in February,May and August,2003 were in one cluster,while the results of 6 surveys in 2004~2005 were in one cluster.This may indicate that the ecological changes between 2003 and 2004~2005 were obvious,and the ecological changes of macrobenthos were affected by the construction of Yangshan deepwater port.