Abstract:The community of macrobenthos was investigated at 32 stations in the southern coastal waters nearby the Shandong Province in August 2006. A total of 182 species were identified, including 92 species of Polychaeta, 29 species of Mollusca, 42 species of Crustacea, 9 species of Echinodermata, and 10 species of minor phyla. Nine of the top ten dominant species (Nephtys oligobranchia, Mediomastus sp., Aricidea fragilis and Sigambra bassi, Leptomya minuta, Paralacydonia paradoxa, Sternaspis scutata, Eudorella pacifica, Lumbrinereis debilis, Prionospio sp.) were polychaetes. The average abundance of the macrobenthos was 2001 ind./m2, and the average biomass was 15.92 g/m2 in the investigated area. The value of Shannon-Wiener index (H¢) of macrobenthos was 2.20~4.59 with an average of 3.92. The value of Margalef’s richness index (d) was 0.99~5.39 with an average of 3.98. The value of Pielou's evenness index (J) was 0.61~0.89 with an average of 0.80. According to the results of CLUSTER analysis, the macrobenthos at the 32 stations could be clustered into two infaunal communities at 36% similarity, which were Mediomastus sp.-N. oligobranchia-Prionospio sp. Community (Community Ⅰ), and N. oligobranchia-A. fragilis-S. bassi Community (Community Ⅱ). The dissimilarity between Community Ⅰand CommunityⅡwas 77.21%. Analysis on Shannon-Wiener index (H¢) showed that all stations were unpolluted except for the 147th station, which suggested that the macrobenthic environment in the investigated area was generally clean. Pearson correlation analysis showed that the abundance and the depth of the water were significantly and negatively correlated (r=–0.38, P<0.05). BIOENV analysis indicated that the most crucial combination of environmental factors for the structure of community was silt + depth + organic carbon (r=0.46). Compared to the results of other previous reports, the average abundance value in our study was the highest. while the average biomass value was the lowest
