Ecology of stress in wild fish in a changing world

鱼类生态和养护生理学实验室的长期目标是清楚地了解环境与个体层面的生理、行为和健康之间的相互关系。换句话说，我们对压力的生态很感兴趣。应激是生态学功能基础的一部分，在确定动物分布和丰度方面起着基础性作用。神经内分泌应激轴(尤其是糖皮质激素的刺激、合成和释放；GC)整合了影响生活史决策的环境信息，例如与能量使用和分配相关的决策，最终影响健康和生存。我们的重点是硬骨鱼，但与之前的大多数研究不同，我们是在生态环境中使用野外野生鱼类进行这一研究的。在过去的五年里，我们的实验室在了解野生鱼类的压力方面取得了实质性的进展。然而，由于人类活动，世界正在迅速变化，这意味着鱼类越来越多地暴露在多种应激源中，其中一些是新奇的。因此，我们的NSERC探索基金的五年目标是在不断变化的世界背景下研究野生鱼类的应激生态学，试图了解(主题A)非生物和生物因素如何调节应激反应和(主题B)应激和应激反应对机体状况、行为和健康的影响。将用于假设检验的科学方法将包括在自然田野(如湖泊、河流)和中生态系统(如实验池塘和溪流)环境中进行广泛的实验和比较调查。对于主题A，我们将在很大程度上依赖于非致命性血液采样和电子标签。我们将通过评估硬骨鱼的主要GC皮质醇的变化来评估种群特定的压力响应变化，并考虑栖息地质量如何影响GC响应。在一些实验中，我们将鱼暴露在不同的保存环境中(例如，操纵热环境和流动)，并评估GC响应性。对于主题B，在放生鱼和观察GC升高的后果之前，我们将主要使用外源性皮质醇处理。在一些实验中，我们将评估应激源如何影响野生鱼的伤口愈合，而在其他研究中，我们将专注于繁殖成功和生存终点。我们还将操纵环境应激源，并考虑季节性和生活史过渡期间可能产生的遗留影响。这项拟议的研究是新颖的，有可能对理解生态过程产生重大影响，特别是在面对环境变化的情况下。综合研究主题跨越基础-应用连续体，将提供对人为环境变化对生物体影响的功能性理解，同时阐明生理过程和种群下降之间的机制关系。例如，这项工作将揭示新的压力源和GC反应之间是否存在不匹配。拟议的工作为培训高素质人员提供了很大的空间，并将有助于确保下一代科学家了解和欣赏人类活动如何影响动物种群以及这些种群提供的生态系统服务。此外，还有相当多的机会让公众和相关利益攸关方参与进来，并为环境管理人员提供使用知识。

The long-term goal of the Fish Ecology and Conservation Physiology Laboratory is to establish a clear understanding of the inter-relationships between the environment and individual-level physiology, behaviour, and fitness. In other words, we are interested in the ecology of stress. Stress is a part of the functional underpinning of ecology and plays a fundamental role in defining animal distribution and abundance. The neuro-endocrine stress axis (particularly the stimulation, synthesis, and release of glucocorticoids; GCs) integrates environmental information that influences life-history decisions such as those related to energy use and allocation, which ultimately influence fitness and survival. We focus on teleost fish, but unlike most previous research, do so in an ecological context using wild fish in field settings. Over the past five years our lab has made substantial progress in understanding stress in wild fish. However, the world is changing rapidly as a result of human activity, which means that fish are increasingly exposed to multiple stressors, some of which are novel. As such, our five-year goal for this NSERC Discovery Grant is to study the ecology of stress in wild fishes in the context of a changing world, attempting to understand (Theme A) how abiotic and biotic factors mediate stress responsiveness and (Theme B) the consequences of stress and stress responsiveness on organismal condition, behaviour, and fitness. The scientific approaches that will be used for hypothesis testing will include extensive experimentation and comparative surveys in natural field (e.g., lakes, rivers) and mesocosm (e.g., experimental ponds and streams) environments. For Theme A we will rely heavily on non-lethal blood sampling combined with electronic tagging. We will evaluate population-specific variation in stress responsiveness by assessing changes in cortisol, the principal GC in teleost fish, and also consider how habitat quality influences GC responsiveness. In some experiments we will expose fish to varied holding environments (e.g., manipulating thermal environment and flow) and evaluate GC responsiveness. For Theme B we will primarily use exogenous cortisol manipulations before releasing fish and observing the consequences of GC elevation. In some experiments we will evaluate how stressors influence wound healing in wild fish, while in other studies we will focus on reproductive success and survival endpoints. We will also manipulate environmental stressors and consider the potential for carryover effects across seasonal and life-history transitions. The proposed research is novel and has the potential to have a substantial influence on understanding ecological processes, particularly in the face of environmental change. The integrative research themes span the fundamental-applied continuum will provide a functional understanding of the effect of anthropogenic environmental change on organisms while elucidating the mechanistic relationships between physiological processes and population declines. For example, the work will reveal whether there is a mismatch between novel stressors and the GC response. The proposed work has substantial scope for training of highly qualified people and will help to ensure that the next generation of scientists has an understanding and appreciation for how human activities influence animal populations and the ecosystem services that these populations provide. In addition, there is considerable opportunity to engage the public and concerned stakeholders and generate knowledge of use to environmental managers.