Aim:Methodology: Results:Interpretation: Key words:The present study was performed to understand the macrobenthic community in 49 stations of intertidal at Garolim Bay during summer.The surface layer sediments and macrobenthos were collected by using the methods employed for the study conducted by Shin et al. (2004) to compare changes in the community of macrobenthos and components of the sediment in the intertidal at Garolim Bay. The improved model of Van 2 Veen grab sampler of 0.045 m of its sampling area was used for sampling of surface layer sediments conducted on a ship in June 2015 at 49 stations placed in the intertidal at Garolim Bay.The sediment environment analysis revealed the mean ratio of sand at 55.50% followed by 41.72% silt and 2.78% clay, respectively. A total of 120 species of intertidal macrobenthos with a density of 630 -2 -2 individuals m were investigated. The mean biomass thereof was 22.59 g wwt m . The most dominant species was polychaetes, Heteromastus filiformis (68.58%), Mediomastus californiensis (9.43%), crustaceans Ilyoplax pingi, crustaceans Macrophthalmus japonicus and so on. After analyzing the correlation coefficient between biotic in and sediment, the abundance and species evenness were found significantly related to environment factors.In this study, six species of polychaete appeared on the top 10 dominant species; and among them, two species of H. filiformis and M. californiensis belonging to Capitellidae were found with 50% habitation density and more than 75% occupancy.

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Swimming crabs, Portunus trituberculatus(Miers) are commercially important off the coasts of Korea, Japan and China. Harvest of swimming crabs has been fluctuated along their distribution ranges. Fluctuations in the interannual harvest of swimming crabs may be correlated with the survival rate during the larval period.The survival rates, intermolt periods, and growth of larval swimming crabs were investigated in the laboratory. Larval swimming crabs are released and undergo development from April to August off the western coast of Korea in the Yellow Sea. Sea surface temperatures off the western coast of Korea during the larval season were used for the laboratory experiments, and ranged from 22 to 26 C. Larvae were individually cultured at four different temperatures, 22 C, 24 C, 26 C, and 28 C. Zoea molted to megalopa at all temperatures and developed to the first crab stage at 24 C, 26 C, and 28 C. Survival rates from zoea I to the first crab stage increased with increasing temperatures. Intermolt period and the growth rate of the mean carapace length were inversely correlated with temperature. Our research helps understand the changes in survival rate and growth of larval swimming crabs resulting from changing oceanic temperatures. Further, our study suggests that the fluctuations in fishery harvest of swimming crabs off the coast of Korea may be related to changes in larval survival affected by changing ocean conditions.

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