Ecology of stress in wild fish in a changing world

鱼类生态及保育生理实验室的长远目标，是建立对环境与个体生理、行为和健康之间相互关系的清晰认识。换句话说，我们对压力的生态学很感兴趣。压力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重要作用。神经-内分泌应激轴（尤其是糖皮质激素的刺激、合成和释放；GCs）整合了影响生命史决策的环境信息，如与能量使用和分配相关的决策，最终影响健康和生存。我们专注于硬骨鱼，但与大多数以前的研究不同，我们是在野外环境中使用野生鱼类的生态背景下进行研究的。在过去的五年中，我们的实验室在了解野生鱼类的压力方面取得了实质性进展。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于多种压力源，其中一些是新的。因此，我们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，试图理解（主题a）非生物和生物因素如何介导应激反应，以及（主题B）应激和应激反应对机体状况、行为和适应性的影响。将用于假设检验的科学方法将包括在自然领域（如湖泊、河流）和生态环境（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，我们将高度依赖非致命性血液采样和电子标签。我们将通过评估硬骨鱼中主要GC皮质醇的变化来评估种群特异性的应激反应变化，并考虑栖息地质量如何影响GC反应。在一些实验中，我们将把鱼暴露在不同的保存环境中（例如，操纵热环境和流量），并评估GC的响应性。对于主题B，我们将主要在释放鱼之前使用外源性皮质醇操纵并观察GC升高的后果。在一些实验中，我们将评估压力源如何影响野生鱼类的伤口愈合，而在其他研究中，我们将重点关注繁殖成功率和生存终点。我们还将操纵环境压力源，并考虑跨季节和生活史转变的潜在延续效应。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，特别是在面临环境变化的情况下。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，同时阐明生理过程与种群下降之间的机制关系。例如，这项工作将揭示在新的应激源和GC反应之间是否存在不匹配。拟议的工作具有培训高素质人才的巨大空间，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，有相当大的机会让公众和有关的利益相关者参与进来，并产生对环境管理人员有用的知识。

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.