Population dynamics in fishes: recruitment processes, environmental variation, adaptation and harvest

鱼类种群的丰富程度是高度可变的，无论是在不同水体之间还是在一个单一水体内进行比较。我的研究计划的目标是了解环境特征和收获控制这些变量种群的程度。似乎这种变异性的大部分来源于鱼类在生命的第一年中生长和生存的变化。因此，我正在研究幼鱼的行为和生理如何影响它们在生长，能量储存和生存方面的早期成功。幼鱼面临着许多挑战，因为它们在第一个冬天很容易受到捕食者和饥饿的影响，如果它们没有储存足够的能量来度过一段几乎没有猎物的时期。我研究了幼鱼如何权衡觅食的时间，这使得它们容易受到捕食者的影响，以及冬季生存所需的足够能量储存的能量限制。通过对比鱼类在不同环境中如何进行这种权衡，我们正在了解这些过程对鱼类生存和适应其家庭环境的重要性。此外，我们感兴趣的是鱼类种群对捕捞的适应能力如何，以及当我们过度捕捞鱼类种群时，幼鱼的产量如何减少。我们对这项工作的一般方法是使用现场实验，观测和模型相结合，以评估环境变化和收获对鱼类种群生存能力的贡献。在不同的环境条件下，我们可以操纵猎物和捕食者的密度和收获率的湖泊中的实验提供了必要的对比，以评估这些因素对鱼类种群变异的贡献。这一基础生物学研究对气候变化和捕捞对鱼类长期可持续性的影响等问题具有重要意义。

The abundance of fish populations is highly variable, whether comparing across water bodies or within a single water body over time. The goal of my research program is to understand the degree to which environmental characteristics and harvest control these variable populations. It appears as if the majority of this variability originates from variation in fish growth and survival during their first year of life. I am therefore studying how the behaviour and physiology of young fish impacts their early success in terms of growth, energy storage and survival. Young fish face many challenges in that they are very susceptible to predators and to starvation during their first winter if they have not stored sufficient energy to survive a period with little prey available. I study how young fish trade-off time spent foraging, which makes them susceptible to predators, with the energetic constraints of sufficient energy storage for winter survival. By contrasting how fish make this trade-off in different environments we are learning the importance of these processes to survival and of adaptation of fish to their home environments. In addition we are interested how resilient fish populations are to harvesting and how the production of young fish is curtailed as we overharvest fish populations. Our general approach to this work is to use a combination of field experiments, observations and models to assess the contribution of environmental variability and harvest to fish population viability. Experiments in lakes which vary in environmental conditions and within which we can manipulate prey and predator density and harvest rate provide the contrasts necessary to assess the contribution of these factors to fish population variability. This fundamental biological research has important implications to issues such as impacts of climate change and harvest on the long-term sustainability of fishes.