Data from: A statistical framework to explore ontogenetic growth variation among individuals and populations: a marine fish example

Growth is a fundamental biological process, driven by a multitude of intrinsic (within-individual) and extrinsic (environmental) factors, that underpins individual fitness and population demographics. Focussing on the comprehensive information stored in aquatic and terrestrial organism hard parts, we develop a series of increasingly complex hierarchical models to explore spatial and temporal sources of growth variation, ranging in resolution from within individuals to across a species. We apply this modelling framework to an extensive data set of otolith increment measurements from tiger flathead (Platycephalus richardsoni), a demersal commercially exploited fish that inhabits the warming waters of south-east Australia. We recreated growth histories (biochronology) up to four decades in length from seven fishing areas spanning this species' range. The dominant pattern in annual growth was an age-dependent, allometric decline that varied amongst individuals, sexes, fishing areas, years and cohorts. We found evidence for among-area differences in growth rate selectivity whereby younger fish at capture were generally faster growers. Temporal growth variation was partitioned into two main sources: extrinsic year-to-year annual fluctuations in environmental conditions and persistent cohort-specific growth differences, reflecting density dependence and/or juvenile experience. Despite low levels of among-individual growth synchrony within areas, we detected a regionally coherent signal of increasing average growth rate through time, a trend related to oceanic warming. At the southerly (poleward) range limit, growth was only weakly related to temperature, but further north in warmer waters this relationship strengthened until at the species' equatorward range limit, growth declined with increasing temperatures. We partitioned these species-wide and area-specific phenotypic responses into within and among-individual components using a reaction norm approach. Individual tiger flathead likely possess sufficient growth plasticity to successfully adapt to warming waters across much of their range, but increased future warming in the north will continue to depress growth, affecting individual fitness and even population persistence. Our modelling framework is directly applicable to other long-term, individual-based, data sets such as those derived from tree rings, corals, and tag-recapture studies, and provides an unprecedented level of resolution into the drivers of growth variation and the ecological and evolutionary implications of environmental and climatic change.

生长是一项基础生物学过程，由众多内在（个体内部）与外在（环境）因素共同驱动，为个体适合度与种群人口统计学提供核心支撑。本研究聚焦水生与陆生生物硬组织中留存的全面信息，构建了一系列复杂度逐步提升的层级化模型，以探究生长变异的时空来源，其分析分辨率覆盖从个体内部到整个物种种群的尺度范围。我们将该建模框架应用于一套涵盖范围广泛的虎鲬（Platycephalus richardsoni）耳石增量（otolith increment）测量数据集——该物种为栖息于澳大利亚东南部变暖海域的底栖商业捕捞鱼类。我们从覆盖该物种分布范围的7个捕捞区域中，重建了最长可达40年的生长历史（生物年代学，biochronology）。年度生长的主导模式为年龄依赖的异速生长衰减，且该模式在个体、性别、捕捞区域、年份以及同生群（cohort）间均存在差异。我们发现了区域间生长速率选择差异的证据：被捕捞时的幼龄个体通常为更快生长者。时间维度的生长变异可划分为两大主要来源：环境条件逐年波动的外在因素，以及反映密度制约（density dependence）或幼体经历的、持续存在的同生群特异性生长差异。尽管区域内个体间的生长同步性较低，但我们检测到了一个区域一致性信号：平均生长速率随时间稳步提升，这一趋势与海洋变暖密切相关。在该物种最南端（向极方向）的分布边界，生长与温度仅存在微弱关联；而在更北侧的暖水环境中，这一关联逐渐增强，直至在该物种的赤道方向分布边界，生长随温度升高而出现下降。我们采用反应规范（reaction norm）方法，将这些全物种及区域特异性的表型响应划分为个体内与个体间两个组分。单个虎鲬个体大概率具备足够的生长可塑性（growth plasticity），以在其分布范围内的大部分变暖海域成功适应，但北部海域未来进一步的变暖将持续抑制生长，进而影响个体适合度乃至种群存续（population persistence）。本研究的建模框架可直接推广应用于其他长期、基于个体的数据集，例如源自树木年轮、珊瑚以及标记重捕（tag-recapture）研究的数据集，其为生长变异的驱动因素，以及环境与气候变化的生态及进化影响，提供了前所未有的解析水平。