@article{oai:meio-u.repo.nii.ac.jp:00000844,
 author = {Arakaki, Yuji and Yamazato, Kiyoshi},
 issue = {3},
 month = {2020-12-03},
 note = {Large scale coral bleaching in Japanese waters, extending from the Ryukyus to southern Kyushyu, occurred in 1998 owing to high seawater temperature. In this study, the authors show population fluctuations of Acanthaster planci before and after this bleaching event, and try to explain the reason for these fluctuations in relation to this event. A. planci, a strong coral predator, prefers to prey on acroporid corals. These corals are easily bleached, and most of them died from the bleaching during the last bleaching event. Thus, it is easy to believe that the decrease of A. planci in the year of coral bleaching is due to the lack of acroporid corals as food for this animal. The data of exterminations at Busena Cape, however, show decreases began in mid-June when seawater temperature began to rise, and about three months before the extensive death of acroporid corals. Adult A. planci have a very narrow tolerance range for temperature, and water temperature above 30℃ has a very big effect on its behavior. Therefore, one could consider the abnormally high seawater temperature starting in mid-June, 1998, as the immediate cause for the sudden decrease in the number of exterminations at Busena Cape in 1998, and the shortage of food for A. plancidue to the subsequent death of coral from bleaching as a contributing cause., 1998年には､高水温が原因であると思われる大規模なサンゴの白化が起こり､日本での白化の規模は琉球列島から九州南部まで及んでいる｡本研究では､サンゴ白化の前後でオニヒトデ個体数の変動を示し､この変動の原因を白化との関連で説明して行くことを試みる｡ミドリイシ類を好んで捕食するオニヒトデは最も強力なサンゴ捕食者の一種である｡ミドリイシ類は白化し易いサンゴ類であり､その殆どは白化により死滅している｡これらより､オニヒトデが餌としているミドリイシ類が白化により殆ど死滅することにより､オニヒトデの餌がなくなりオニヒトデが減少したと考えることができる｡しかし､部瀬名岬におけるオニヒトデ駆除の記録では､オニヒトデ駆除数の減少はミドリイシ類の大規模な斃死の約3ケ月前で､水温の上昇し始めた6月中旬であることを示している｡成体のオニヒトデは温度耐性が極めて狭く､約30℃でオニヒトデの行動に大きな影響を与える事がわかっている｡これより､部瀬名岬で行なわれたオニヒトデ駆除数の急激な減少の第一の要因は1988年6月中旬に始まった異常高水温であり､サンゴの白化後の餌不足が第二の要因であると考察される｡, application/pdf},
 pages = {1--11},
 title = {Coral bleaching, rise in sea temperature, and the population of Acanthaster planci in Okinawa},
 year = {}
}