Distributional Pattern of Macrobenthic Invertebrates on the Shallow Subtidal Sandy Bottoms near Kangrung, East Coast of Korea

This study was carried out to investigate the distribution pattern of macrobenthos in the subtidal sandy bottoms of the east coast of Korea, and seasonal samplings were performed from April 1993 to February 1994. The species number of macrobenthos was in the range from 70 in winter to 109 in spring season. Polychaete worms were the most dominant faunal group in species richness and abundance, but mollusks showed the highest biomass. The mean density of macrobenthos fluctuated from 631 individuals/m in autumn to 1,995 individuals/m in summer. The major macrofauna in abundance were polychaetes, Spiophanes bombyx which occurred all seasons with top rank and Prionospio sp. and a mollusk, Alvenius ojianus, and crustaceans, Wecomedon sp. and Urothoidae spp. were also numerically dominant macrobenthic fauna. The macrobenthos in the study area were classified into two assemblages by water depth. However, they showed a different community structure near small rivers in autumn and winter seasons.