Development of the Escape Response in Xyrauchen Texanus: Do Razorback Suckers have Poor Escape Performance?

逃跑反应是一种反射性行为，它使鱼类能够迅速地游离捕食者。这种行为被认为对幼鱼特别重要，因为它们经常被其他鱼类和无脊椎动物捕食。事实上，人们认为，许多本地鱼类目前正在从科罗拉多河消失的主要原因是它们的幼虫被引进的鱼类吃掉了。因此，逃逸反应的表现可能对本地鱼类的持续生存至关重要。本项目将研究一种本地鱼类——刺背吸盘（Xyrauchen texanus）的幼虫的逃逸反应的发展。此外，另一种底栖鱼类虹鳟鱼（Oncorhynchus mykiss）的逃避反应性能也将在发育过程中进行测量，并与虎背鱼的表现进行比较。虹鳟鱼提供了一个有趣的生态对比，有几个原因：(1)它们不是原产于科罗拉多河，但目前大量生活在那里；(2)它们的幼虫可以与其他掠食性鱼类一起在栖息地生存；(3)众所周知，它们成年后会捕食小的虎背吸盘。对于这两个物种，肌肉骨骼和神经系统的发育将被量化，以确定它们对逃避反应性能的潜在贡献。最后，本研究将使用两个实验温度来评估科罗拉多河近期温度变化对逃逸反应性能的作用，并允许将这些研究中收集的数据与先前为其他硬骨鱼收集的数据进行直接比较。

The escape response is a reflexive behavior that allows fish to swim rapidly away from predators. This behavior is believed to be particularly important for larval fishes, which are contstantly preyed upon by other fish and invertebrates. In fact, it is thought that the main reason many species of native fish are currently disappearing from the Colorado River is that their larvae are consumed by introduced fish species. Thus, escape responses performance may be of critical importance in the continued survival of native fish species. This project will examine the development of the the escape response in the larvae of a native fish species, the razorback sucker (Xyrauchen texanus). In addition, escape response performance of another fish with benthic larvae, the rainbow trout (Oncorhynchus mykiss), will also be measured during development and compared to the performance of the razorback sucker. Rainbow trout provide an interesting ecological comparison with the razorback sucker for several reasons: (1) they are not native to the Colorado River, but currently live there in large numbers, (2) their larvae can survive in habitats with other predatory fishes, and (3) they are known to prey on young razorback suckers as adults. For both species, the development of the musculoskeletal and the nervous systems will be quantified to determine their potential contributions to escape response performance. Finally, two experimental temperatures will be used in this study to assess the role of recent temperature changes in the Colorado River on escape response performance, and to allow direct comparisons of the data colleted in these studies with data collected previously for other teleosts.