Distribution of macrobenthos in spring and autumn in the East China Sea

This paper presents the results of ecological study of the macrobenthic fauna in the East China Sea in autumn and spring. materials were collected from 30 stations located between 121°～127°E and 26°～32°N in November 2000 and April 2001. For quantitative analysis, samples were collected by 0.1 m 2 box corer. Two successful grabs were regarded as one sample at a station. Samples were prepared by removing the mud and sand by whirlpool mud remover, filtering the specimens through a 0.1 mm sieve, and fixing them in 75% alcohol for small samples or 10% formalin for large. For qualitative analysis, samples were collected with a 1.5 m width×0.5 m height Agassiz trawl, effectively trawling for 15 minute at 2 knots speed, fixing the specimens as per the quantitative analysis. Biomass was measured by weighing the wet specimens with a 1/1000 gram precision electric balance. Altogether in the samples, 392 species of macrobenthos were identified, which belong respectively to Polychaeta, 95 species, Mollusca, 131 species, Crustacea, 118 species and Echinodermata, 48 species. Based upon the analysis of the data obtained during the survey, biomass of the macrobenthos averaged 7.21 g/m 2 in spring and 8.79 in fall, and density averaged 132.95 individuals/m 2 in spring and 101.45 in fall. There were no clear differences in density or distribution of the macrobenthos between spring and fall. In autumn, some species migrate from shore and Changjiang Estuary to the Kuroshio Current. Compared with the benthos research results of The comprehensive resource investigation of Chinese coast and shallow waters (1958～1960) and the Survey of Jinxing Vessel (1975～1976) in the same region, the distribution pattern and the ecological characteristics of the macrobenthos have not changed dramatically, although the biomass in spring of 2001 was lower than that of 1959.