EAPSI: Determining the Response of Migratory Fish to Environmental and Climatic Variability

这项研究将与奥塔哥大学的主要鱼类洄游专家Gerard Closs博士合作完成，并将确定影响鱼类成功洄游的因素和条件。这项研究的意义可以广泛地理解在快速变化的环境和气候条件下影响洄游物种的因素，这将是确定经常受到威胁的洄游鱼类未来种群动态的基础，并将为这些受威胁种群的保护和管理提供信息。气候变化可以影响淡水和海洋水生系统中可用的营养物质，从而影响迁移生物在这两种环境之间的成功移动，称为二生境。此外，河流流量可受到气候/环境变化的影响，直接影响迁徙个体的成功。在这项研究中，我们将评估气候过程（如El Niño）如何影响溪流流量以及海洋和淡水营养物质的可用性，以确定两种洄游鱼类Gobiomorphus cotidianus和galaxas argentius的迁徙成功是否受到影响。这项研究将评估从代表不同溪流流量和养分生产力的溪流中收集的样本，并将使用MODIS卫星图像来确定海洋环境中养分可用性的变化如何影响迁移成功。气候变率可影响淡水和海洋系统的生产力，从而影响这些系统之间水生移徙者的成功（即二栖）。迁徙的成功会随着环境条件的变化而波动，比如水流或生产力。本研究的主要假设是，气候变化（即El Niño）通过沿溪流流量和生产力梯度采样两种二栖物种，Gobiomorphus cotidianus和galaxas argentius，通过影响溪流流量状况以及海洋和淡水生产力，改变了移民和居民的成功。耳石微观结构和微化学分析将用于确定个体在不同气候条件下从淡水溪流迁移到海洋环境的速率（ENSO指数）。MODIS卫星图像将用于分析沿海生产力对跨越养分/生产力梯度的迁移倾向的影响，而土地利用/土地变化卫星图像将用作河流生产力的代理，以确定跨越陆地养分梯度的迁移速率动态。该奖项由美国国家科学基金会和新西兰皇家学会共同资助，隶属于东亚和太平洋暑期学院项目，支持一名美国研究生进行暑期研究。

This research will be completed in collaboration with leading fish migration expert, Dr. Gerard Closs at the University of Otago, and will identify factors and conditions influential to the success of migration in fishes. The implications of this study can be drawn broadly to understand the factors that influence migratory species under rapidly changing environmental and climatic conditions which will be foundational in determining future population dynamics of, often threatened, migratory fishes and will provide information for conservation and management of these threatened populations. Climate variability can influence the nutrients available in freshwater and marine aquatic systems which can subsequently affect the success of migratory organisms to move between those two environments, called diadromy. Additionally, stream flow can be influenced by climatic/environmental variability directly influencing the success of migratory individuals. In this study, we will evaluate how climatic processes, like El Niño, affect stream flow and marine and freshwater nutrient availability to determine if migration success is influenced in two migratory fish species, Gobiomorphus cotidianus and Galaxias argentius. This study will evaluate samples collected from streams representative of varying stream flow and nutrient productivity and will use MODIS satellite images to determine how changes in nutrient availability in the marine environment might influence migration success. Climate variability can affect the productivity of freshwater and marine systems influencing the success of aquatic migrants between those systems (i.e., diadromy). Migratory success can fluctuate in response to variable environmental conditions such as stream flow or productivity. The primary hypothesis of this study is that climate variation (i.e., El Niño) alters the success of migrants and residents by affecting stream flow regimes and marine and freshwater productivity by sampling two diadromous species, Gobiomorphus cotidianus and Galaxias argentius along stream flow and productivity gradients. Otolith microstructure and microchemistry analysis will be used to determine the rate at which individuals migrate from freshwater streams to marine environments under different climatic conditions (ENSO index). MODIS satellite images will be used to analyze the influence of coastal productivity on migration propensity across a nutrient/productivity gradient while land use/land change satellite imagery will be used as proxy for stream productivity to determine migration rate dynamics across a terrestrial nutrient gradient. This award, under the East Asia and Pacific Summer Institutes program, supports summer research by a U.S. graduate student and is jointly funded by NSF and the Royal Society of New Zealand.