Size structuring and allometric scaling relationships in coral reef fishes

Temperate marine fish communities are often size structured, with predators consuming increasingly larger prey and feeding at higher trophic levels as they grow. Gape limitation and ontogenetic diet shifts are key mechanisms by which size structuring arises in these communities. Little is known, however, about size structuring in coral reef fishes.
Here, we aimed to advance understanding of size structuring in coral reef food webs by examining the evidence for these mechanisms in two groups of reef predators. Given the diversity of feeding modes amongst coral reef fishes, we also compared gape size—body size allometric relationships across functional groups to determine if they are reliable indicators of size structuring.
We used gut content analysis and quantile regressions of predator size—prey size relationships to test for evidence of gape limitation and ontogenetic niche shifts in reef piscivores (n=13 species) and benthic invertivores (n=3 species). We then estimated gape size—b...

温带海洋鱼类群落通常具有体型结构特征，即捕食者随着个体生长，会捕食体型逐渐增大的猎物，并在更高营养级进行摄食。颌骨限制（gape limitation）与个体发育食性转变（ontogenetic diet shifts）是这类群落形成体型结构的核心机制。然而目前对珊瑚礁鱼类的体型结构特征仍知之甚少。

本研究旨在通过对两类礁栖捕食者的上述两种机制开展验证，加深对珊瑚礁食物网体型结构的认知。鉴于珊瑚礁鱼类摄食模式的多样性，我们还比较了不同功能群的颌骨大小与体型的异速生长关系，以判断其是否可作为体型结构的可靠指示指标。

我们通过胃含物分析以及捕食者体型-猎物体型关系的分位数回归（quantile regressions），验证了礁栖食鱼动物（n=13种）与底栖无脊椎动物捕食者（n=3种）存在颌骨限制与个体发育生态位转变的证据。随后我们估算了颌骨大小—b……