Ecosystem models forced by future climate simulations outputs from the Coupled Model Intercomparison Project Phase 5 (CMIP5) simulate a substantial decline of tropical marine animal biomass over the course of the 21st century. Regional projections are however far more uncertain because of well-known biases common to most CMIP5 historical simulations that propagate within the food web. Moreover, the model outputs for high trophic levels marine fauna suffer from lack of validation based on in situ data. In this study, we implement a “bias-mitigation” strategy to reduce the physical oceanography and biogeochemical biases simulated by three CMIP5 models under the future RCP8.5 scenario. We force two very different micronekton models with these “bias-mitigated” outputs to infer the future micronekton changes in the Coral Sea: a 3-D deterministic population dynamics model; and a 3-D statistical model based on in situ hydro-acoustic data. These two models forecast a consistent pattern of micronekton abundance changes in the epipelagic layer (0–150 m) by 2100 for three different climate forcing used, with a marked decrease south of 22°S and a smaller increase further north mostly related to temperature and chlorophyll changes. In contrast, changes in the vertical patterns of micronekton predicted by the two models considerably differ in the upper mesopelagic layers (150–450 m) and lower mesopelagic layer (450–1000 m), highlighting the structural sensitivity in model type. Since micronekton are prey of all larger marine predators, those discrepancies in vertical structures of micronekton may hamper our potential to predict how top predators may evolve in the future.

未来的气候模拟所推动的生态系统模型是耦合模型比较项目第5阶段（CMIP5）的输出，模拟了21世纪热带海洋动物生物量的大幅下降。然而，由于在食物网中传播的大多数CMIP5历史模拟所共有的众所周知的偏差，因此区域预测的不确定性要大得多。此外，高营养水平海洋动物的模型输出缺乏基于原位的验证数据。在这项研究中，我们实施了“缓解偏见”策略，以减少在未来的RCP8.5方案下由三种CMIP5模型模拟的物理海洋学和生物地球化学偏见。我们用这些“偏向缓解”的输出结果来强制使用两种截然不同的微神经元模型，以推断珊瑚海中未来的微神经元变化：3-D确定性种群动力学模型；和基于原位的3D统计模型水声数据。这两个模型预测，到3100年使用的三种不同的气候强迫作用，上表层（0-150 m）内微核丰度变化的模式将保持一致，在22°S以南明显下降，在更北的较小上升主要与温度和温度有关。叶绿素变化。相比之下，两种模型预测的微神经元垂直模式的变化在中上弹性层（150-450 m）和中下弹性层（450-1000 m）上有很大差异，突出了模型类型的结构敏感性。由于微浮游生物是所有较大的海洋捕食者的猎物，因此，微浮游生物的垂直结构中的差异可能会妨碍我们预测未来顶级捕食者可能如何进化的潜力。