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.

这项初步研究是在 1985 年至 1988 年间，在琉球群岛西表岛的珊瑚礁保护和管理以及棘蚶控制方面进行的，该地区的珊瑚礁到 1985 年已受到海星的严重破坏。珊瑚恢复正在进行中。四种常见顶孔珊瑚的重量增长在浅水或清澈水域中比在浅水或清澈水域中更快（约 0.7%/天）据计算，Acropora nobilis 一年内表面积增加 0.79 - 1.08 m^2。 Acropora planci 的繁殖季节是从 5 月下旬到 6 月中旬。在 28 - 32 °C 的温度下比在 20 - 26 °C 的温度下孵化更快，孵化后 11 - 13 小时。 6 月至 8 月期间，在 28 - 32 °C 和 20 °C 下授精 33 小时。 ./m^2) 在 1986 年，并且在接下来的几年中要低得多 1986 年和 1986 年的队列。 1987 年，在 9 - 11 个月龄时将其食物改为珊瑚（直径 15 - 25 毫米）。在藻类摄食阶段，它们的生长速度为 2 - 3 毫米/月，在珊瑚摄食阶段为 8 - 15 毫米/月。 1986 年群体的一部分在两年内成熟。Drupella cornus 是已确定的 11 种以珊瑚为食的腹足动物中最常见的一种，其最大摄食率为鹿角珊瑚为 5.8 厘米^2/ind./day。目前对棘蚴幼虫的发现将有助于预测爆发以及在爆发早期阶段开始控制计划的可能性，尽管棘蚴是最有害的。对于珊瑚礁来说，当珊瑚礁恢复时，应考虑包括腹足动物在内的其他捕食者。