Changes in the structure of a fish assemblage following macroalgal overgrowth on an Acanthaster-infested coral reef

棘蚫虫出没的珊瑚礁上大型藻类过度生长后鱼类群落结构的变化

• 批准号: 09660193
• 负责人: SANO Mitsuhiko
• 金额: $ 1.22万
• 依托单位: The University of Tokyo
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1997
• 资助国家: 日本
• 起止时间: 1997 至 1999
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09660193/
• 关键词: Dead corals; Macroalgal area; Acanthaster planci; Fish assemblage; オニヒトデ; 死滅サンゴ

At Amitori Bay of Iriomote Island, one of the Ryukyu Islands of Japan, staghorn corals were completely killed with Acanthaster planci between 1981 and 1982. By 1986, all of the dead corals had collapsed drastically, and a flat plain of low-relief coral rubble remained. Since around 1994, a regular increase in the cover of erect fleshy macroalgae has occurred in an area at the plain, attaining about 36% cover in 1999, although some other areas have undergone recovery of corals. I examined, therefore, the patterns of responses of a fish assemblage to a large increase in macroalgae on a coral reef degraded by an outbreak of A. planci in October from 1997 to 1999.Five transects 20 m long and I m wide were established on the macroalgal area and rubble area without erect algae. Fishes (adults and juveniles) on each transects were counted by direct observation.The mean number of species of adults per transect showed no significant difference between the algal area and rubble area every year from 1997 to 1999. The mean number of adult individuals was significantly greater in the algal area than in the rubble area each year, but the density of the former area remained low. For juveniles, on the other hand, there were no significant differences between the two areas in the mean numbers of species and individuals each year. These facts suggest that dominance of reefs by macroalgae following extensive mortality of corals has only a little effect on the structure of fish assemblages.

1981年至1982年，在日本琉球群岛之一的伊里奥默特岛的阿米托里湾，鹿角珊瑚被阿卡萨斯特（Acanthaster planci）杀死。到1986年，所有死去的珊瑚都急剧倒塌，只剩下一片低矮的珊瑚碎石平原。大约自1994年起，在平原的一个地区，直立的肉质大型藻类的覆盖范围定期增加，在1999年达到约36%，虽然其他一些地区的珊瑚也有所恢复。因此，我研究了在1997年10月至1999年10月因蚤蚤爆发而退化的珊瑚礁上，鱼类群落对大型藻类大量增加的反应模式。在大型藻区和无直立藻的碎石区分别建立了长20 m、宽1 m的5个样带。每个样带上的鱼（成鱼和幼鱼）采用直接观察计数。1997 ~ 1999年，每样带平均成虫种数在藻区和碎石区之间无显著差异。赤潮区每年平均成虫数明显高于碎石区，但赤潮区密度较低。另一方面，幼鱼的年平均种数和个体数在两个地区之间没有显著差异。这些事实表明，在珊瑚大量死亡之后，大型藻类在珊瑚礁中的优势地位对鱼类组合的结构只有很小的影响。

项目成果

Mitsuhiko Sano: "Stability of reef fish assemblages : responses to coral recovery after catastrophic predation by Acanthaster planci"Marine Ecology Progress Series. (印刷中). (2000)

Mitsuhiko Sano：“珊瑚礁鱼类组合的稳定性：对棘蝽灾难性捕食后珊瑚恢复的反应”海洋生态学进展系列（2000 年）。

Mitsuhiko Sano: "Stability of reef fish assemblages: responses to coral recovery after catastrophic predation by Acanthaster planci"Marine Ecology Progress Series. (印刷中). (2000)

Mitsuhiko Sano：“珊瑚礁鱼群的稳定性：对棘蝽灾难性捕食后珊瑚恢复的反应”海洋生态学进展系列（2000 年）。

Sano, Mitsuhiko: "Stability of reef fish assemblages : responses to coral recovery after catastrophic predation by Acanthaster planci."Marine Ecology Progress Series. (in press). (2000)

Sano，Mitsuhiko：“珊瑚礁鱼类群落的稳定性：棘蛉灾难性捕食后对珊瑚恢复的反应。”海洋生态学进展系列。