Length–weight relationships (LWRs) are a fundamental tool for the non-intrusive determination of biomass, a unit of measure that facilitates the quantification of ecosystem and fisheries productivity. LWRs have been defined and broadly applied for many marine species across a range of ecosystems, especially regarding fishes. However, LWRs are yet to be determined for the majority of marine taxa, particularly for small cryptic organisms that are difficult to census and poorly described. On coral reefs, the motile cryptofauna represent the greatest density and diversity of metazoan taxa that likely support critical steps in trophic pathways, but little empirical data exist beyond biodiversity assessments. We evaluated LWRs for 42 groups of motile cryptofauna across four microhabitats (live Acropora, live Pocillopora, dead branching coral and coral rubble) in Palau, Western Micronesia. We employed a robust methodology to determine LWRs by comparing the suitability of a series of linear, quadratic, polynomial and power models. Using the best-fit equations for each group, we provide the first documented LWRs for motile cryptofauna, namely at the level of family. LWRs were well fit (R2 > 0.90) for 45% of the groups and reasonable (R2 > 0.70) for 76%. The presence, size and weight of cryptofauna varied among microhabitats with the size distribution of 13 groups significantly influenced by habitat type. Establishment of these LWRs provides critical baseline information regarding an overlooked group on coral reefs, making population data on the cryptofauna more accessible to support future research aiming to characterise the roles of these taxa in ecosystem functioning and trophodynamics.

中文翻译：

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量化活动珊瑚礁隐匿动物生物量的长度-重量关系

长度-重量关系 (LWR) 是非侵入式确定生物量的基本工具，生物量是一种促进生态系统和渔业生产力量化的度量单位。轻水堆已被定义并广泛应用于一系列生态系统中的许多海洋物种，尤其是鱼类。然而，大多数海洋分类群的 LWR 尚未确定，特别是对于难以普查和描述不充分的小型隐蔽生物。在珊瑚礁上，能动的隐匿动物代表了后生动物类群的最大密度和多样性，它们可能支持营养途径中的关键步骤，但除了生物多样性评估之外，几乎没有经验数据。我们评估了四个微型栖息地（活鹿角目、活 Pocillopora、死分枝珊瑚和珊瑚碎石）在西密克罗尼西亚帕劳。通过比较一系列线性、二次、多项式和功率模型的适用性，我们采用了一种稳健的方法来确定 LWR。使用每个组的最佳拟合方程，我们提供了第一个记录在案的活动隐匿动物 LWR，即在家庭级别。45% 的组的 LWR 拟合良好 (R2 > 0.90)，76% 的组合理 (R2 > 0.70)。隐匿动物的存在、大小和重量在微生境之间存在差异，其中 13 个群体的大小分布受生境类型的影响显着。这些 LWR 的建立提供了关于珊瑚礁上被忽视的群体的关键基线信息，