Sizing Ocean Giants

What are the greatest sizes that the largest marine megafauna obtain? This is a simple question with a difficult and complex answer. Many of the largest-sized species occur in the world’s oceans. For many of these, rarity, remoteness, and quite simply the logistics of measuring these giants has made obtaining accurate size measurements difficult. Inaccurate reports of maximum sizes run rampant through the scientific literature and popular media. Moreover, how intraspecific variation in the body sizes of these animals relates to sex, population structure, the environment, and interactions with humans remains underappreciated. Here, we review and analyze body size for 25 ocean giants ranging across the animal kingdom. For each taxon we document body size for the largest known marine species of several clades. We also analyze intraspecific variation and identify the largest known individuals for each species. Where data allows, we analyze spatial and temporal intraspecific size variation. We also provide allometric scaling equations between different size measurements as resources to other researchers. In some cases, the lack of data prevents us from fully examining these topics and instead we specifically highlight these deficiencies and the barriers that exist for data collection. Overall, we found considerable variability in intraspecific size distributions from strongly left- to strongly right-skewed. We provide several allometric equations that allow for estimation of total lengths and weights from more easily obtained measurements. In several cases, we also quantify considerable geographic variation and decreases in size likely attributed to humans.

何为海洋巨型生物所能达到的最大体型？此问题看似简单，实则答案复杂而深邃。众多体型最大的物种分布在全球各大洋之中。对于其中许多物种，其稀有性、地理位置的偏远性以及测量这些巨兽的物流难题使得获取准确的体型测量数据变得异常困难。关于最大体型的不准确报告在科学文献和大众媒体中广泛流传。此外，这些动物体型内的种间变异与性别、种群结构、环境以及与人类的相互作用之间的关系尚未得到充分认识。在本研究中，我们对25种来自动物王国的海洋巨型生物的体型进行了回顾和分析。对于每个分类群，我们记录了已知最大海洋物种的体型数据。我们还分析了种内变异，并确定了每个物种中已知最大的个体。在数据允许的情况下，我们分析了种内体型随空间和时间的变化。同时，我们还提供了不同尺寸测量之间的异速生长方程，以供其他研究人员参考。在某些情况下，由于数据不足，我们无法对这些主题进行全面考察，因此我们特别强调了这些数据缺陷和数据收集存在的障碍。总体而言，我们发现种内体型分布存在显著的变异性，从显著左偏到显著右偏均有涉及。我们提供了几个异速生长方程，这些方程允许根据更易获取的测量值来估算总长度和体重。在几个案例中，我们还量化了地理变异以及体型减小，这很可能与人类活动有关。