Causes and consequences of the trade-off between compensatory growth and swim performance in teleost fish

对许多动物来说，体型越大越好。较大的体型减少了被捕食者吃掉的风险，也可以导致动物能够产生的后代数量的增加。尽管增加体型有这些明显的好处，但越来越多的证据表明，大多数生物体并没有以生理上可能的最大速度生长，而且快速生长实际上可能会带来巨大的代价。补偿性生长（许多生物体在一段时间的食物剥夺后发生的快速生长）为研究这些潜在成本提供了有用的手段，在鱼类中，经历了一段时间的生长补偿的个体往往在以后的生活中表现出较低的游泳能力。虽然这种代价可能对生存和繁殖成功都有重要影响，但在补偿性生长和游泳能力受损之间进行权衡的潜在机制尚不清楚。对于鱼类的补偿性生长反应的个体差异，以及个体之间的成本差异程度，我们也一无所知。总的来说，由于缺乏知识，我们不可能准确预测补偿生长对个体鱼的生存和繁殖成功的影响，以及它对野生鱼类种群动态的影响。这类信息很有价值，特别是考虑到由于气候变化等因素，粮食供应波动的可能性越来越大。拟议的研究将检查单个鱼的肌肉纤维结构，生物化学，代谢和游泳性能，以深入了解生长速度和游泳性能之间权衡的机制。将进行更多的实验室研究，以检查捕食者的存在对生长反应中个体差异的影响，并研究补偿性生长对个体冒险行为和繁殖成功的影响。最后，利用基于个体的数学模型的理论研究将通过结合经验推导的变异性估计来研究生长速率变化对个体适合度的影响，从而补充这些实验室实验。总的来说，这项跨学科的研究将使我们更好地理解鱼类快速生长的代价的机制基础，以及这种权衡对行为和进化生态学的影响。

For many animal species, bigger is better. Larger body size reduces the risk of being consumed by predators, and can also lead to an increase in the number of offspring that an animal is able to produce. Despite these apparent benefits of increased body size, mounting evidence suggests that most organisms do not grow at the maximum rates that are physiologically possible, and that there may actually be significant costs associated with rapid growth. Compensatory growth (the rapid growth which occurs in many organisms after a period of food deprivation) provides a useful means to study these potential costs, and in fish, individuals that have undergone a period of growth compensation tend to display reduced swimming performance later in life. While such a cost could have an important influence on both survival and reproductive success, the underlying mechanism responsible for this trade-off between compensatory growth and impaired swimming ability is not understood. There is also nothing known about individual variation in the compensatory growth response in fishes, and the extent to which the costs may differ between individuals. Overall, our lack of knowledge makes it impossible to accurately predict the consequences of compensatory growth for the survival and reproductive success of individual fish, and its effects on the dynamics of wild fish populations. Such information would be valuable, especially considering the increased likelihood of fluctuations in food availability due to factors such as climate change. The proposed research will examine muscle fibre structure, biochemistry, metabolism, and swim performance in individual fish to gain insights into the mechanisms responsible for the trade-off between growth rate and swim performance. Additional laboratory studies will be performed to examine the influence of predator presence on individual variation in the growth response, and also to study the consequences of compensatory growth for individual risk-taking behaviour and reproductive success. Finally, theoretical studies utilizing individual-based mathematical models will compliment these laboratory experiments by incorporating empirically-derived estimates of variability to investigate the implications of variation in growth rate for individual fitness. Overall, this interdisciplinary study will allow us to better understand the mechanistic underpinnings of the costs of rapid growth in fish, and also the consequences of this trade-off for behavioural and evolutionary ecology.