Momigliano Paolo, Harcourt Robert, Robbins William D, Stow Adam
Department of Biological Sciences, Macquarie University, Sydney, 2109 New South Wales, Australia.
Sydney Institute of Marine Science, 19 Chowder Bay Road, Mosman, 2088 New South Wales, Australia.
Sci Rep. 2015 Aug 28;5:13229. doi: 10.1038/srep13229.
Grey reef sharks (Carcharhinus amblyrhynchos) can be one of the numerically dominant high order predators on pristine coral reefs, yet their numbers have declined even in the highly regulated Australian Great Barrier Reef (GBR) Marine Park. Knowledge of both large scale and fine scale genetic connectivity of grey reef sharks is essential for their effective management, but no genetic data are yet available. We investigated grey reef shark genetic structure in the GBR across a 1200 km latitudinal gradient, comparing empirical data with models simulating different levels of migration. The empirical data did not reveal any genetic structuring along the entire latitudinal gradient sampled, suggesting regular widespread dispersal and gene flow of the species throughout most of the GBR. Our simulated datasets indicate that even with substantial migrations (up to 25% of individuals migrating between neighboring reefs) both large scale genetic structure and genotypic spatial autocorrelation at the reef scale were maintained. We suggest that present migration rates therefore exceed this level. These findings have important implications regarding the effectiveness of networks of spatially discontinuous Marine Protected Areas to protect reef sharks.
灰礁鲨（Carcharhinus amblyrhynchos）可能是原始珊瑚礁上数量占优势的高阶捕食者之一，然而即使在管理严格的澳大利亚大堡礁海洋公园，它们的数量也在下降。了解灰礁鲨在大尺度和精细尺度上的遗传连通性对于其有效管理至关重要，但目前尚无遗传数据。我们沿着1200公里的纬度梯度，对大堡礁的灰礁鲨遗传结构进行了调查，并将实证数据与模拟不同迁移水平的模型进行了比较。实证数据未显示在所采样的整个纬度梯度上存在任何遗传结构，这表明该物种在大堡礁的大部分区域有规律地广泛扩散和基因流动。我们的模拟数据集表明，即使有大量迁移（高达25%的个体在相邻珊瑚礁之间迁移），大尺度遗传结构和珊瑚礁尺度上的基因型空间自相关仍然得以维持。因此我们认为目前的迁移率超过了这个水平。这些发现对于空间上不连续的海洋保护区网络保护礁鲨的有效性具有重要意义。
