ABSTRACT: Determining predator diets is essential for understanding the strength of top-down processes and how they cascade through food webs. This is especially important for sponges, key members of benthic communities, whose dominance has increased in recent years on some coral reefs. However, the diversity of spongivorous fishes and the sponges they consume are relatively unknown. Here, we estimated sponge consumption by spongivorous fishes in the Wakatobi Marine National Park, Indonesia. We deployed cameras to identify fish biting at the dominant reef sponge Xestospongia spp. and then used gut content analysis and fish abundance estimates to quantify sponge consumption. In total, 33 species from 10 families of reef fish were identified taking bites from Xestospongia spp.; however, the 2 most prolific sponge-grazers, Ctenochaetus binotatus and Chaetodon kleinii, had no sponge in their guts, showing that for some fish, bites on sponge surfaces are not reliable evidence of sponge consumption. Gut contents indicated that Pygoplites diacanthus was an obligate spongivore, while Pomacanthus imperator, P. xanthometopon, Zanclus cornutus and Siganus punctatus regularly consumed sponges. Sponge consumption by these 5 spongivores was estimated at 46.6 ± 18.3 g sponge 1000 m^-2 d^-1. Molecular approaches developed to sequence the 18S gene for sponges consumed by angelfishes led to the successful amplification of 14 consumed sponges representing 6 orders of Porifera. We provide the first estimate of sponge consumption in the Indo-Pacific and are the first to successfully sequence partially digested sponges from fish stomachs, identifying several sponges previously unknown to be consumed by spongivores.

中文翻译：

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对印度-太平洋珊瑚礁海绵消耗率的估计

摘要：确定捕食者的饮食对于了解自上而下过程的强度以及它们如何通过食物网级联是必不可少的。这对于底栖群落的关键成员海绵尤其重要，近年来它们在一些珊瑚礁上的主导地位有所增加。然而，肉食性鱼类及其消耗的海绵的多样性相对未知。在这里，我们估算了印度尼西亚 Wakatobi 海洋国家公园中食虫鱼类的海绵消耗量。我们部署了摄像头来识别鱼类在占主导地位的珊瑚礁海绵Xestospongia spp 上的咬伤。然后使用肠道内容分析和鱼类丰度估计来量化海绵消耗。总共确定了 10 个珊瑚鱼科的 33 个物种被Xestospongia咬伤属; 然而，两种最多产的海绵食草动物，Ctenochaetus binotatus和Chaetodon kleinii，它们的内脏中没有海绵，这表明对于某些鱼来说，海绵表面的叮咬并不是海绵消费的可靠证据。肠道内容物表明Pygoplites diacanthus是专性海绵动物，而Pomacanthus imperator、P. xanthometopon、Zanclus cornutus和Siganus punctatus经常食用海绵。这 5 种食肉动物的海绵消耗量估计为 46.6 ± 18.3 g 海绵 1000 m ^-2 d ^-1. 开发用于对神仙鱼消耗的海绵的 18S 基因进行测序的分子方法导致代表 6 个 Porifera 目的 14 只消耗的海绵的成功扩增。我们提供了印度-太平洋地区海绵消费的首次估计，并且是第一个成功对鱼胃中部分消化的海绵进行测序的人，确定了几种以前未知的海绵动物消费的海绵。