The community structure of macrozoobenthos and its temporal change on the Gapo artificial tidal flat in Masan Bay, Korea

Abstract

The surface sediment consisted of fine particles, but the grain size at the tidal flat has changed from mud to muddy sand by adding coarse particles for manila clam aquaculture by local fishermen from 2002. A total of 35 faunal species including 23 species at the upper tidal flat, 28 species at the lower tidal flat and 30 species in the tidal channel were collected during the study period. Polychaete worms were the most dominant fauna in species number and total faunal density, but mollusks were the most dominant in biomass. There was a specific species composition along tidal level. At the upper tidal flat, Prionospio japonicus, Sigambra tentaculata, and Neanthes succinea were dominant and at the lower tidal flat, N. succinea, P. japonicus, Corophium sinensis, and Ruditapes philipinarum were dominant while S. tentaculata, Paraprionospio coora, and C. sinensis were dominant at the tidal channel. In the feeding guild composition of the community, the surface deposit feeder (SDF) was the most abundant functional group followed by carnivores. The abundance and biomass showed a seasonal fluctuation they decreased during summer seasonal and recovered in autumn. The benthic pollution index (BPI) reflecting the trophic composition of macrozoobenthic community at each site remained in a very low level during most study period, which indicates the macrobenthic community of the Gapo artificial tidal flat has been in a disturluding 23 species at the upper tidal flat, 28 species at the lower tidal flat and 30 species in the tidal channel were collected during the study period. Polychaete worms were the most dominant fauna in species number and total faunal density, but mollusks were the most dominant in biomass. There was a specific species composition along tidal level. At the upper tidal flat, Prionospio japonicus, Sigambra tentaculata, and Neanthes succinea were dominant and at the lower tidal flat, N. succinea, P. japonicus, Corophium sinensis, and Ruditapes philipinarum were dominant while S. tentaculata, Paraprionospio coora, and C. sinensis were dominant at the tidal channel. In the feeding guild composition of the community, the surface deposit feeder (SDF) was the most abundant functional group followed by carnivores. The abundance and biomass showed a seasonal fluctuation they decreased during summer seasonal and recovered in autumn. The benthic pollution index (BPI) reflecting the trophic composition of macrozoobenthic community at each site remained in a very low level during most study period, which indicates the macrobenthic community of the Gapo artificial tidal flat has been in a distur