To assess the effectiveness of the temperate coral, Alveopora japonica as an impact indicator, we examined the effects of various environmental variables on the coral’ short-term population dynamics in Tateyama Bay, Chiba, Japan. We measured coral cover, colony den-sity and colony size of A. japonica in June, August and November 2013. Newly identified colonies were recorded separately. We analyzed the relationships between colony density, substrate types, and seawater temperature using a generalized linear mixed model. Both coral cover and colony density decreased between August and November, showing high mortality during this period. In November, a decrease in mean colony size and skewness of colony size distribution, compared with August, was attributed to mortality of large colonies and an increase in the abun-dance of small colonies. Newly identified small colonies were observed in August and November. The presence of these colonies may be in part due to accelerated planulation (i.e., recruitment). The generalized linear mixed model showed a significant trend of increasing colony density with seawater temperature rise, potentially resulting from recruitment during the high-temperature period. In addi-tion, there was a negative effect of sand substrate on colony density. Since the sand substrate abundance was significantly correlated with typhoon occurrence, we sug-gest that typhoons could be one of the major factors affecting the short-term population dynamics of A. japonica in Tateyama Bay.