Construction of artificial habitats has recently received attention as a technique for environmental remediation. In order to collect fundamental information that is required to develop efficient artificial habitats for remediation, an artificial habitat with experimental units (including plates of various densities), was set-up on the sea floor of the shore of Awaji Island, Japan. We observed the transition in the composition and biomass of the benthic community that inhabited the artificial habitat over three years. The artificial habitat was inhabited by 85 sessile and 218 mobile species. The number of species and biomass differed among the experimental units. Initially, the number of species was large ; and the biomass per surface area of the plates increased as the density of the plates decreased. The temporal changes in the biomass of the species were classified into four pattems, namely 'initial increase', 'later increase' , 'seasonal fluctuation' and 'irregular fluctuation'. Although the composition of the benthic communities that formed on the experimental units differed in the early stage, the proportion of large and camivorous species was high and the communities were similar in every experimental unit by the end of the experiment. We concluded that the climax community was hardly affected by the density or surface area of the plates in the artificial habitat within the context of the experiment.
