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Studies on the conservation and management of coral reefs and the control of Acanthaster planci juveniles.

珊瑚礁保护管理及棘蛉幼体控制研究。

基本信息

批准号：
60440017
负责人：
HABE Tadashige
金额：
$ 10.56万
依托单位：
Tokai University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (A)
财政年份：
1985
资助国家：
日本
起止时间：
1985 至 1988
项目状态：
已结题

项目摘要

This primary study was made for conservation and management of coral reefs and control of Acanthaster Planci during the years 1985 to 1988 in the northwestern Iriomote Island, Ryukyu Islands. Coral reefs of the area has been badly damaged by the starfish by 1985. At present, coral recovery are in progress.Weight increment of four common Acroporid corals was faster in shallow or clear waters (around 0.7 %/day) than in deep or turbid waters (around 0.4 %/day). Acropora nobilis was calculated to increase 0.79 - 1.08 m^2 of surface area in a year.Breeding season of A. planci was from late May to the middle of June. Its embryos developed faster at temperatures of 28 - 32 ゜C than at 20 - 26 ゜C. Its hatching occurred 11 - 13 hours after the insemination at 28 - 32 ゜C and 33 hours at 20 ゜C. Planktonic larvae of starfishes occurred from June to August. The algae-feeding Acanthaster juveniles were collected mostly on the reef slopes from July. Its density was highest (0.82/ind./m^2) in 1986 and much lower in the following years. The cohorts of 1986 and 1987 switched their food to coral at ages of 9 - 11 months (15 - 25 mm in diameter). Their growth rates were 2 - 3 mm/month in algae-feeding phase and 8 - 15 mm/month in coral-feeding phase. A part of the 1986 cohort matured in two years.Drupella cornus was the commonest among 11 species of coral-feeding gastropods identified. Its maximum feeding rate for Acropora was 5.8 cm^2/ind./day.The present findings of Acanthaster juveniles would contribute to the forecast of the outbreaks and to the possibility of commencing the control program in earlier stage of the outbreaks. Though A. planci is the most harmful to the reef corals, other predators including the gastropod should be taken into account when coral reefs are recovering.

1985 ~ 1988年在西表岛西北部海域进行了珊瑚礁的保护与管理以及浮游植物的控制等方面的初步研究。到1985年，该地区的珊瑚礁已被海星严重破坏。目前，珊瑚正在恢复中，四种常见的顶孔珊瑚在浅水或清澈的沃茨中的重量增长（约0.7%/日），较深水或浑浊的沃茨中（约0.4%/日）为快。通过计算，鹿角珊瑚每年可增加表面积0.79 ~ 1.08 m^2。planci为5月下旬至6月中旬。它的胚胎在28 - 32摄氏度的温度下比在20 - 26摄氏度下发育得更快。受精后11 ~ 13小时，28 ~ 32 ℃孵化，20 ℃孵化33小时。海星浮游幼虫发生在6 - 8月。从7月开始，主要在礁坡上采集了食藻的海葵幼鱼。其密度最高（0.82个/只）。1986年为m^2，随后几年更低。1986年和1987年的队列在9 - 11个月大时将食物改为珊瑚（直径15 - 25毫米）。摄食期的生长速率为2 ~ 3 mm/月，摄食期为8 ~ 15 mm/月。1986年的一部分在两年内成熟。在11种已鉴定的以珊瑚为食的腹足动物中，角螺是最常见的。对鹿角珊瑚的最大摄食率为5.8cm^2/ind.本研究结果将有助于预测该病的发生，并为在该病发生的早期开展防治工作提供依据。虽然A.对珊瑚的危害最大，珊瑚礁在恢复时，应考虑其他掠食者，包括腹足类。