EAPSI: The role of freshwater-marine migratory behaviors on dispersal in Pacific Oceanic Islands fishes

许多鱼类仅限于海洋或淡水环境，但在30,000种有鳍鱼中，约有250种在淡水和咸水之间游来游去，通常是为了繁殖目的，例如鲑鱼和鳗鱼。这一行为很重要，因为海洋岛屿上的许多小溪都会发生变化。风暴、干旱、火山活动和污染往往会使岛上的小溪在一段时间内无法居住，并可能导致当地完全灭绝的淡水物种。随着时间的推移，无法殖民邻近的溪流可能会导致一个物种的灭绝。虽然复水生物将扩散能力限制在特定的生命阶段，但许多复水生物物种的地理分布横跨多个海洋。为了解决这些问题，这项研究旨在了解迁徙模式的变化如何影响鱼类种群中的基因流动。为了确定迁徙行为，将与台湾大学著名的耳石微化学技术专家萧仁杰博士合作，使用耳石微量化学技术。然后，可以将种群之间流动的遗传信息水平与不同的迁徙策略进行比较。物种将从台湾各地的多条溪流中采集(除了关岛和帕劳)。耳石微量化学是一种识别鱼类一生中环境中化合物的技术，将被用于将鱼类分类为水栖、海洋或淡水。为了了解这些不同的生活史模式对扩散的重要性，遗传标记将被用来推断岛状海洋鱼类的基因流和种群结构。DNA序列的变化将被比较，以了解溪流和岛屿之间的运动模式。该项目将有助于弥合生活史变异的生态重要性和基因流动的进化意义之间的挥之不去的鸿沟。这项NSF EAPSI奖是与台湾国家科学委员会合作资助的。

Many fishes are limited to marine or freshwater environments, but about 250 of 30,000 ray-finned fishes are diadromous, or migrate between fresh and saltwater, usually for reproduction purposes, e.g., Salmon and eel. This behavior is important because many small streams on oceanic islands are subject to variation. Storms, droughts, volcanic activity and pollution can often make small insular streams become uninhabitable for periods of time and can lead to local extinction of a completely freshwater species. Over time, the inability to colonize neighboring streams can lead to a species' extinction. While diadromy limits opportunities for dispersal ability to a specific life stage, many diadromous species have geographic distributions which span multiple oceans. To address these issues, this research aims to understand how variations in migration pattern affect the flow of genes across fish populations. To determine migratory behvior, otolith microchemistry techniques will be used, in collaboration with Dr. Jen-Chieh Shiao, a prominent expert in this technique at the National Taiwan University. Levels of genetic information moving between populations can then be compared to varying migration strategies. Species will be collected from multiple streams around Taiwan (in addition to Guam and Palau). Otolith microchemistry, a technique that identifies chemical compounds in a fish's environment over the course of their life, will be used to classify fishes as diadromous, marine, or freshwater. To understand the importance of these different life-history patterns on dispersal, genetic markers will be used to infer gene flow and population structure of insular oceanic fishes. Variation in DNA sequences will be compared to understand patterns of movement between streams and islands. This project will help bridge the lingering gap between the ecological importance of variation in life history and evolutionary significance of gene flow. This NSF EAPSI award is funded in collaboration with National Science Council of Taiwan.