Population irruptions of crown-of-thorns starfish (Acanthaster spp.) contribute greatly to the degradation of coral reefs throughout the Indo-Pacific. Effective management of these population irruptions is limited, in part, by incomplete knowledge of their early life history. Importantly, there are very limited data on the distribution and abundance of newly settled crown-of-thorns starfish (0 + starfish, in their first year since settlement). Extensive sampling was conducted around the circumference of three distinct mid-shelf reefs (at 1–18 m depths) in the central Great Barrier Reef (GBR), during active population irruptions, in May–June 2017, to quantify the occurrence and densities of settlement-stage starfish (2–65 mm diameter) and relate patterns of abundance to distinct habitat features at the scale of individual reefs. Overall, 140 settlement-stage starfish were detected across 1242 quadrats (1 m2). Settlement-stage starfish were recorded from 31 out of 42 sites (73.8%) at mean densities of 0–0.77 starfish m−2. Both estimated densities and the likelihood of occurrence of settlement-stage starfish within quadrats increased overall with the proportion of coral rubble (and dead intact corals), were greatest at intermediate depths (8–14 m), but decreased with the proportion of live hard coral. At the scale of individual reefs, settlement-stage starfish occurred most frequently in south-western and northern fore reef habitats. Our results suggest that settlement and/or early post-settlement survival of crown-of-thorns starfish is greatest in relatively shallow waters of obliquely exposed fore reef habitats where there is high cover of coral rubble. The specific occurrence of these habitat types (within spur and groove systems and rubble slips) provides an opportunity to concentrate searches and increase effective sampling of settlement-stage starfish, though these habitats are relatively widespread and unlikely to constrain the population replenishment or population irruptions of crown-of-thorns starfish on the GBR.

中文翻译：

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澳大利亚大堡礁定居阶段棘冠海星的栖息地协会

棘冠海星（Acanthaster spp.）的种群数量激增对整个印度-太平洋地区的珊瑚礁退化起到了很大的作用。有效管理这些人口暴发的部分原因是对其早期生活史的了解不完整。重要的是，关于新定居的棘冠海星（0 + 海星，自定居后的第一年）的分布和丰度的数据非常有限。2017 年 5 月至 6 月期间，在大堡礁 (GBR) 中部的三个不同的中架礁石（深度 1-18 m）周围进行了广泛的采样，以量化珊瑚礁的发生率和密度。定居阶段的海星（直径 2-65 毫米），并将丰度模式与单个珊瑚礁规模的不同栖息地特征联系起来。全面的，在 1242 个样方（1 平方米）中检测到 140 只沉降阶段海星。从 42 个地点中的 31 个地点（73.8%）记录了沉降阶段海星，平均密度为 0-0.77 海星 m-2。估计密度和在象限内出现沉降阶段海星的可能性总体上随着珊瑚碎石（和死亡的完整珊瑚）的比例增加，在中间深度（8-14 m）最大，但随着生活硬珊瑚的比例下降珊瑚。在单个珊瑚礁的尺度上，沉降期海星最常出现在西南和北部的前礁栖息地。我们的结果表明，在珊瑚碎石覆盖率高的倾斜暴露的前礁栖息地的相对较浅的水域中，棘冠海星的沉降和/或早期沉降后存活率最高。