Macroalgal beds have been suggested to be an important settlement habitat for a diversity of reef fishes, yet few studies have considered how the composition or structure of macroalgal beds may influence fish settlement. The aim of this study was to investigate how the physical characteristics of Sargassum beds, a common macroalga on inshore coral reefs, influence the abundance of recently-settled rabbitfishes (Siganidae) on Orpheus Island, Great Barrier Reef. The abundance of recently-settled rabbitfish (< 3 cm total length), the density and height of Sargassum thalli, and benthic composition were quantified within replicate 1-m2 quadrats across 15 mid-reef flat sites. A total of 419 recently-settled rabbitfish from three species (Siganus doliatus, S. lineatus and S. canaliculatus) were recorded across 150 quadrats (range 0–16 individuals m−2), with S. doliatus accounting for the majority (85.2%) of individuals recorded. The abundance of S. doliatus and S. lineatus was greatest at moderate Sargassum densities (ca. 20–30 holdfasts m−2) and generally increased with Sargassum height and the cover of ‘other’ macroalgae. These findings demonstrate the potential importance of the physical characteristics of macroalgal beds to the settlement of rabbitfishes on inshore reef flats.

中文翻译：

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马尾藻的密度和高度影响大堡礁近海礁滩上的比目鱼 (f. Siganidae) 定居

大型藻床被认为是多种珊瑚鱼的重要定居栖息地，但很少有研究考虑大型藻床的组成或结构如何影响鱼类的定居。本研究的目的是调查马尾藻床（近海珊瑚礁上常见的大型藻类）的物理特征如何影响大堡礁奥菲斯岛最近定居的兔鱼（Siganidae）的丰度。最近定居的比目鱼的丰度（总长度 < 3 厘米）、马尾藻的密度和高度以及底栖组成在 15 个中礁平坦地点的重复 1 平方米样方内进行了量化。来自三个物种（Siganus doliatus、S. lineatus 和 S. canaliculatus）的 419 条最近定居的比目鱼被记录到 150 个样方（范围为 0-16 个个体 m-2），S. doliatus 占记录的个体的大多数（85.2%）。S. doliatus 和 S. lineatus 的丰度在中等马尾藻密度（约 20-30 保持 m-2）时最大，并且通常随着马尾藻高度和“其他”大型藻类的覆盖而增加。这些发现证明了大型藻床的物理特征对兔鱼在近海礁滩上定居的潜在重要性。