Long-term changes of Zoanthus spp. in the infra-littoral zone at Taisho Lava Field, Sakurajima, Kagoshima, Japan

Abstract

Changes in the surface cover and distribution of the encrusting anemone Zoanthus spp. in the infra-littoral zone at Sakurajima, Kagoshima, Japan were investigated in 1982, and during the period between 1995 and 2002. A belt transect (1×50m) was marked off, and using a 1×1m quadrat with 10cm×10cm subdivisions and scuba gear, the cover, colony size, and distribution data were collected. Data were analyzed in relation to seawater temperature and Sakurajima volcanic ash-fall data. It is most likely that abnormally high observed seawater temperatures (almost 30°C) in the summer of 1998 had a detrimental effect on the subject Zoanthus. In addition, it is conceivable that irregular scattered volcanic ash fall may also have a detrimental effect.