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To elucidate the organic matter sources in soft-bottom macrozoobenthos at Tongyeong, Korea, macrozoobenthos and their potential food sources were sampled in May 2004, and their C and N stable isotope compositions were analyzed. In total we collected 128 macrozoobenthic species, which ranged from 465 to 3,775 individuals/(average 2,108 ind.) in density and from 47.8 to 539.9 gwwt/(average 366.0 gwwt/) in biomass. Cluster and multi-dimensional scaling analyses indicated that the macrozoobenthic community was divided into two distinct groups. Coastal inner stations, where commercial fish cages were established, were dominated by Amphioplus ancistrotus, Scoletoma longifoila and Tharyx sp., whereas open sea stations were dominated by Chaetozone spinosa, Scoletoma longifolia and Capitella capitata. values of sedimentary organic matter showed a distinct gradient in the range of -18.4 to , with a declining trend from the coastal inner stations to open sea stations. This probably reflects the settling rate of organic wastes such as feces and pellets from fish cages near the coastal inner stations. The macrozoobenthos showed a broad range from -19.5 to at the coastal inner stations, and a relatively narrow range from -21.3 to at the open sea stations. values of macrozoobenthos paralleled those of sedimentary organic matter, Our isotope results suggested that macrozoobenthos near the coastal inner stations used organic wastes derived from fish cages along with phytoplankton, whereas the macrozoobenthos near the open sea stations used organic wasters derived mainly from phytoplankton.

This study examined distributional patterns of Asterias amurensis in Tongyeong, the central South Sea of Korea. The density of the sea star was estimated at 10 chosen sites in the inner and the outer parts of the Tongyeong coast from December 2000. The mean density of the species in this area was . The seasonal surveys conducted at 3 arbitrary chosen sites (i.e., sea cage, reef and soft sediment) also showed that the abundance of the species at the sea cage site was significantly higher than at the reef site and the soft sediment site . Densities were higher at sea cages areas than at reefs and soft bottom sites. At sea cage site, A. amurensis population exhibited a strong aggregated distributional pattern. In contrast, at reef and soft bottom sites, A. amurensis population showed a random distributional pattern. The spatial difference in prey species and its abundance was the primary factor determining the spatial heterogeneity of the sea star in its behavior characteristics. Experiments on the feeding preference indicated that A. amurensis had a strong selectivity on its prey, but this selectivity varied between populations living in different sites. In particular, A. amurensis populations at the reef site showed a strong selectivity on various sessile and mobile animals living in reef areas, suggesting that these animal groups may play a role as "windows for the survival of A. amurensis". These results suggest that the distribution of A. amurensis in Tongyeong is closely associated with abundance of prey species and the bottom composition.

The fauna associated with mussel (Mytilus galloprovincialis) beds and vertical distribution of macrobenthos were studied on the Goijeong rocky shore in Jinhae Bay, Korea. Sampling was conducted seasonally using a quadrate from January to October, 1998. In the first experiment, to reveal the community structure of macrobenthos in mussel bed, a total of 62 species were identified, which included polychaetes molluscs (16 spp.), crustaceans (10 spp.), and others. The density-dominant species were Pseudopolydora antennata, Nereis heterocirrata, Littorina brevicula and Balanus kondakovi. And the density of associated fauna was correlated with that of mussel (r

Seasonal variations of species composition and density of caprellids was accomplished in eelgrass beds around Daedo Island, a south coast of Korea. Sampling was performed monthly using an epifaunal sampler at two stations from June 1996 to May 1997, Caprellids were comprised of 6 species belong to a family Caprellidae, Mean density was 402 ind./. The numerically-dominant species were Caprella tsugarensis (216 ind./) and C. kroeyeri (129 ind./). High density was occurred in the early summer, and lows in autumn and winter. The density of caprellids was correlated with the biomass of the eelgrass. Predation pressure by fish was also correlated with the density of caprellids in spring.