Dissertation Research: Morphology and Swimming Ability of Trout: Do Body Shape and Swimming Stamina Differences Mediate the Invasion of Native Cutthroat Trout Populations?

非本地鱼类对世界范围内许多鱼类种群的减少和灭绝负有责任。在北美西部，引进非本地虹鳟鱼（Oncorhynchus mykiss）经常导致本地切喉鳟鱼（O. clarki）种群的减少和灭绝。这些物种在溪流中有着相似的生态环境，因此它们被认为是在争夺有限的资源。与亲缘关系密切的鱼类一样，切喉鳟鱼和虹鳟鱼能够杂交产生可育的杂交后代。杂交鳟鱼的竞争能力可能对剩余的本地凶猛种群的入侵有很强的影响。初步结果表明，虹鳟鱼和与黄石赤喉鳟鱼杂交的第一代虹鳟鱼比黄石赤喉鳟鱼更有竞争力。除了行为差异外，体型对鲑科鱼类的竞争互动和游泳能力也很重要。这项提议的目的是研究黄石赤喉鳟鱼、虹鳟和它们的杂交品种在形态和游泳能力上的差异。亲本鳟鱼和杂交鳟鱼将在一个共同的环境中饲养，以确定形态学的遗传基础，并确定非本地和杂交鳟鱼是否具有更高的持续游泳能力，从而提供竞争优势。这项研究的广泛影响将是更好地了解引进鳟鱼取代本地鳟鱼的机制。本项目将支持一名博士研究生的论文研究。

Nonnative fishes are responsible for declines and extinction of many fish populations worldwide. In western North America, the introduction of nonnative rainbow trout (Oncorhynchus mykiss) frequently leads to the decline and extinction of native cutthroat trout (O. clarki) populations. These species share a similar ecology in streams, thus they are thought to compete for limited resources. As is common in closely related fish species, cutthroat and rainbow trout are able to interbreed producing fertile hybrid offspring. The competitive abilities of hybrid trout may have strong effects on the invasion of remaining native cutthroat populations. Preliminary results indicate that rainbow trout and first generation hybrids with Yellowstone cutthroat trout (O. c. bouvieri) are better competitors for feeding territories than native Yellowstone cutthroat trout. In addition to behavioral differences, body shape is important to competitive interactions and swimming ability in salmonid fishes. The goal of this proposal is to investigate differences in morphology and swimming abilities between Yellowstone cutthroat trout, rainbow trout, and their hybrids. Parental and hybrid trout will be raised in a common environment to determine the genetic basis of morphology and to determine if nonnative and hybrid trout have a higher sustained swimming ability which could provide a competitive advantage. The broader impact of this research will be to provide a better understanding of the mechanisms by which introduced trout are replacing native trout. This project will support the dissertation research of a doctoral candidate.