Exploring the larval fish community of the central Red Sea with an integrated morphological and molecular approach

An important aspect of population dynamics for coral reef fishes is the input of new individuals from the pelagic larval pool. However, the high biodiversity and the difficulty of identifying larvae of closely related species represent obstacles to more fully understanding these populations. In this study, we combined morphology and genetic barcoding (Cytochrome Oxidase I gene) to characterize the seasonal patterns of the larval fish community at two sites in close proximity to coral reefs in the central-north Red Sea: one shallower inshore location (50 m depth) and a nearby site located in deeper and more offshore waters (~ 500 m depth). Fish larvae were collected using oblique tows of a 60 cm-bongo net (500 μm mesh size) every month for one year (2013). During the warmer period of the year (June-November), the larval fish stock was comparable between sampling sites. However, during the colder months, abundances were higher in the inshore than in the offshore waters. Taxonomic composition and temporal variation of community structure differed notably between sites, potentially reflecting habitat differences, reproductive patterns of adults, and/or advective processes in the area. Eleven out of a total of 62 recorded families comprised 69–94% of the fish larval community, depending on sampling site and month. Richness of taxa was notably higher in the inshore station compared to the offshore, particularly during the colder period of the year and especially for the gobiids and apogonids. Two mesopelagic taxa (Vinciguerria sp. and Benthosema spp.) comprised an important component of the larval community at the deeper site with only a small and sporadic occurrence in the shallower inshore waters. Our data provide an important baseline reference for the larval fish communities of the central Red Sea, representing the first such study from Saudi Arabian waters.

珊瑚礁鱼类种群动态的一个重要方面是来自远洋幼虫群体的新个体输入。然而，高生物多样性和识别亲缘关系密切物种幼虫的困难，构成了更全面理解这些种群所面临的障碍。在本研究中，我们结合形态学和遗传条形码（细胞色素氧化酶I基因）对红海中部-北部两个靠近珊瑚礁地点的幼虫鱼群季节性模式进行了表征：一个较浅的近岸位置（深度50米）以及一个位于更深且更远海的水域的邻近地点（约500米深度）。使用60厘米的斜向拖网（500微米网目尺寸）每月收集鱼幼虫，持续一年（2013年）。在一年中较温暖的时期（6月至11月），幼虫鱼群在采样地点之间相当。然而，在较冷的月份，近岸水域的丰度高于远海。两个地点的物种组成和群落结构的时空变化差异显著，可能反映了栖息地差异、成鱼繁殖模式以及该区域的平流过程。在总共记录的62个科中，有11个科（占总数的69-94%）构成了幼虫鱼群的重要组成部分，具体取决于采样地点和月份。与远岸相比，近岸站点的物种丰富度显著更高，尤其是在一年中的较冷时期，尤其是对于鲈形目和刺尾鱼目。两种中层远洋物种（Vinciguerria sp. 和 Benthosema spp.）构成了较深地点幼虫群落的一个重要组成部分，在较浅的近岸水域中只有少量且偶尔出现。我们的数据为红海中部的幼虫鱼群提供了一个重要的基线参考，代表了来自沙特阿拉伯水域的首个此类研究。