Short-term population dynamics of high-latitude <i>Alveopora japonica</i> in Tateyama Bay, Japan

Abstract

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's short-term population dynamics in Tateyama Bay, Chiba, Japan. We measured coral cover, colony density 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 abundance 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 addition, 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.Keywords Alveopora japonica, coral population, fluo rescence, typhoon, substrate IntroductionTateyama Bay, Chiba, Japan is at the northern limit of zooxanthellate coral distribution on the western side of the Pacific Ocean. Twentyfour scleractinian coral species (20 genera) have been recorded around Tateyama (Veron 1992). Alveopora japonica, an endemic species around Korea and Japan (Veron 2000), is one of the dominant temperate scleractinian coral species in this region (Hagiwara 2003). The species is found at Tanegashima (Veron 1992), Miyake-jima (Tribble and Randall, 1986) and Tateyama (Veron 1992) on the western side of the Pacific Ocean, and in the Amakusa Islands (Nozawa et al. Denis et al. 2013Denis et al. , 2015, which was also suspected to be due to a seawater temperature rise (Denis et al. 2015). High-latitude corals can be used as impact indicators of environmental changes, especially seawater temperature rise caused by global warming (Yamano 2008). Information on population structure and short-term dynamics is necessary to assess the effectiveness of a coral species as an impact indicator; however, such information on A. japonica is currently limited (Nozawa et al. 2008; Denis et al. 2013 Denis et al. , 2015 Vieira et al. in press).In this study, we examined the effects of various environmental variables on the short-term population dynamics of A. japonica. We measured coral cover, colony density and colony size of A. japonica along the coast of Tateyama Bay, and analyzed the relationships am...

The complete mitochondrial genome of Alveopora japonica (Scleractinia: Acroporidae)

“…Alveopora japonica Eguchi 1968 is a zooxanthellate scleractinian coral belonging to the family Acroporidae. This species is generally distributed in high-latitude regions of East Asia, such as Korea (Jeju Island), Japan, and Taiwan (Denis et al 2013;Matsumoto et al 2016;Vieira et al 2016). Growth forms of A. japonica are hemispherical or massive with ellipsoidal skeletons, and its colonies are dark green to brownish green (Veron and Stafford-Smith 2000).…”

“…Alveopora japonica is designated as Vulnerable on the IUCN Red List (IUCN 2008) and included in CITES Appendix II (CITES 1990) with other scleractinian corals. Their Threatened status is primarily because of the susceptibility to bleaching, harvesting for the aquarium trade, and typhoon-induced sedimentation or physical damage (Matsumoto et al 2016). However, due to the effects of climate change, the population of A. japonica is actually increasing in Jeju Island in Korea, at odds with the general trend of coral populations (Denis et al 2014).…”