Temperature Influences Selective Mortality during the Early Life Stages of a Coral Reef Fish
Temperature Influences Selective Mortality during the Early Life Stages of a Coral Reef Fish
复制标题
温度影响珊瑚礁鱼生命早期阶段的选择性死亡
作者：
Tauna L. Rankin;S. Sponaugle
对于具有复杂生命周期的生物体，在生命阶段之间的界面发生的过程可能对生存和种群动态产生不成比例的影响。温度是影响变温动物生长的重要因素，而生长相关过程往往与生存相关。我们研究了水温对从幼虫到早期幼鱼阶段过渡期间的生长相关早期生活史特征（ELHTs）和差异死亡率的影响，在美国佛罗里达群岛上的珊瑚礁上取样了16个月的双色小鲷（stegastuspartitus）。对定居和幼鱼的耳石分析结合环境数据表明，平均近礁水温解释了幼鱼早期生活中上层幼虫持续时间（PLD）、早期幼虫生长、定居时尺寸和生长的重要变化。在所有队列中，幸存的幼体在定居时始终较大，但在定居后的前6 d内生长较慢。对于其他ELHTs，选择性死亡率随季节变化：在冬季和春季，幸存者表现出更快的幼虫生长和更短的PLD，而在温暖的夏季，PLD的选择逆转，幼虫生长的选择成为非线性的。我们的研究结果表明，温度不仅塑造了生长相关性状，而且可以影响选择性死亡的方向和强度。
For organisms with complex life cycles, processes occurring at the interface between life stages can disproportionately impact survival and population dynamics. Temperature is an important factor influencing growth in poikilotherms, and growth-related processes are frequently correlated with survival. We examined the influence of water temperature on growth-related early life history traits (ELHTs) and differential mortality during the transition from larval to early juvenile stage in sixteen monthly cohorts of bicolor damselfish Stegastes partitus, sampled on reefs of the upper Florida Keys, USA over 6 years. Otolith analysis of settlers and juveniles coupled with environmental data revealed that mean near-reef water temperature explained a significant proportion of variation in pelagic larval duration (PLD), early larval growth, size-at-settlement, and growth during early juvenile life. Among all cohorts, surviving juveniles were consistently larger at settlement, but grew more slowly during the first 6 d post-settlement. For the other ELHTs, selective mortality varied seasonally: during winter and spring months, survivors exhibited faster larval growth and shorter PLDs, whereas during warmer summer months, selection on PLD reversed and selection on larval growth became non-linear. Our results demonstrate that temperature not only shapes growth-related traits, but can also influence the direction and intensity of selective mortality.