Dissertation Research: Evaluating changes in food web linkages and mercury bioaccumulation by top predators in response to the removal of an introduced predator

这个项目将调查移除一种在北方湖泊中发现的广泛引入的非本地捕食者的食物网效应。50多年前，小嘴鲈鱼被引入研究湖，这导致了本地猎物鱼类丰度的减少和主要食物网的变化。2000年实施的一项小嘴鲈鱼清除计划导致了本地猎物鱼类丰度的增加，食物网联系的恢复（使用鱼类组织中的稳定同位素测量），以及顶级捕食者中汞浓度的变化。项目目标是：1）量化湖泊鱼类群落、食物网联系和汞生物累积的变化，这些变化是由于正在进行的清除工作而发生的，2）评估造成这些变化的过程，3）评估捕食者清除/控制作为管理湖泊生态系统的一种工具。其通常用于在北美湖泊中提供休闲垂钓机会。这项研究的结果将提供一个改进的能力：1）使用稳定的同位素在鱼类组织作为湖泊恢复的度量，2）了解和改变过程中负责汞积累的运动鱼类，和3）实施管理方法，以恢复本地鱼类群落的影响占主导地位的非本地物种。

This project will investigate the food web effects of removing a widely introduced non-native predator found in northern lakes. Smallmouth bass were introduced into the study lake more than 50 years ago, which resulted in reduced abundance of native prey fish and major food web changes. A smallmouth bass removal program implemented in 2000 resulted in increased native prey fish abundance, restoration of food web linkages (measured using stable isotopes in fish tissue), and changes in mercury concentrations in top predators. Project goals are to: 1) quantify changes in lake fish communities, food web linkages and mercury bioaccumulation that have occurred in response to the ongoing removal effort, 2) evaluate the processes responsible for these changes, 3) and evaluate predator removal/control as a tool to manage lake ecosystems.Limited information is available regarding the effects of large-scale predator manipulations, which are commonly implemented to provide recreational angling opportunities in North American lakes. Results from this study will provide an improved ability to: 1) use stable isotopes in fish tissue as a metric for lake restoration, 2) understand and alter processes responsible for mercury accumulation in sport fish, and 3) implement management approaches to restore native fish communities impacted by dominant non-native species.