Macrobenthos In Jiaozhou Bay Ecological Studies

The ecological study of macrofauna was conducted on four typical sampling stations selected in the northern muddy bottom area of Jiaozhou Bay, estuary of Dagu River, culturing and nearby area in Hangdao in Mar., Jun., Aug. and Dec., 2002. Abundance and biomass of macrofauna were investigated by quantitative study. The macrobenthic community structure and biodiversity were analyzed through multivariate statistic analysis. The ABC method (abundance biomass comparison) was used to detect pollution-induced disturbance in marine benthic communities.Total of 138 species were identified. The total mean abundance, biomass and secondary production were l,719inds.-m-2, 27.17gw.w.-m-2 and 2.24gC-m-2-a-1, respectively. The estimated total annual secondary production of macrobenthos was 28,000tC in Jiaozhou Bay. Compared with the data published on macrobenthic ecology in this area, there was a significant increase in the present abundance and a remarkable decrease in the biomass. There was a big change in the macrobenthic community structure in Jiaozhou Bay during the last two decades. Some dominant species were disappeared. The present diversity index was same as that of investigation in 1995. The comparison curves of the abundance and biomass indicate that the macrobenthic community in the northern muddy bottom area has been disturbed moderately. There was no disturbance detected in culturing area, but the abundance of some species with small size was dominant there.Compared with the studies on macrofauna in Bohai Sea and Southern Yellow Sea,the macrobenthic abundance and biomass in Jiaozhou Bay were less than those of two seas. But the macrobenthic secondary production in Jiaozhou Bay was more than that of the Bohai Sea.Using the sieves with 0.5mm aperture mesh in sorting quantitative macrobenthic samples shows more advantages than that of using sieves with 1mm aperture mesh.