The enhanced or reduced growth of juvenile masu salmon (Oncorhynchus masou masou) may result from climate changes to their environment and thus impact on the eco-evolutionary dynamics of their life-history choices. Male juveniles with status, i.e., if their body size is larger than a threshold, stay in the stream and become resident males reproducing for multiple years, while those with smaller status, i.e., their body size is below the threshold, migrate to the ocean and return to the stream one year later to reproduce only once. Since juvenile growth is suppressed by the density of resident males, the fraction of resident males may stay in equilibrium or fluctuate wildly over a 2-year period. When the threshold value evolves, the convergence stable strategy may generate either an equilibrium or large fluctuations of male residents. If environmental changes occur faster than the rate of evolutionary adaptation, the eco-evolutionary dynamics exhibit a qualitative shift in the population dynamics. We also investigated the relative assessment models, in which individual life-history choices are made based on the individual’s relative status within the juvenile population. The eco-evolutionary dynamics are very different from the absolute assessment model, demonstrating the importance of understanding the mechanisms of life history choices when predicting the impacts of climate change.

幼体马苏鲑鱼（Oncorhynchus masou masou）可能是由于气候变化对其环境造成的，从而影响了他们的生活史选择的生态进化动力学。具有状况的雄性少年，即如果其体形大于阈值，则留在溪流中并成为繁殖多年的常住雄性，而具有较小状况的雄性少年，例如其体形小于阈值，则迁移到海洋中并在一年后返回信息流，仅复制一次。由于常住雄性的密度抑制了幼年的生长，所以常驻雄性的比例可能在两年内保持平衡或剧烈波动。当阈值变化时，收敛稳定策略可能会导致男性居民均衡或大幅波动。如果环境变化发生的速度快于进化适应的速度，生态进化动力学在人口动力学上显示出质的变化。我们还研究了相对评估模型，其中基于个体在青少年群体中的相对地位来选择个体的生活史。生态进化动力学与绝对评估模型有很大的不同，表明在预测气候变化的影响时，了解生活史选择机制的重要性。