Paul Schueller is an aquatic population ecologist. In his research, he is interested in learning about how populations of aquatic animals, mainly fish, change through time and what influences this change. Additionally, he is very interested in how human activities influence aquatic population processes. More importantly, he is interested in quantifying these effects in a manner that can help prioritize remediation. Currently, Paul is researching how fragmentation of stream networks effects fish movement within headwater streams of the Connecticut River basin. In the Connecticut River basin, stream networks can become fragmented in several ways. The major causes of habitat fragmentation are poorly constructed road culverts and dams, but old fish weirs and even stone walls can cause obstructions to fish movement. Brook trout, Salvelinus fontinalis, are found in most streams within the Connecticut River basin. This makes them a good species to study when trying to understand how stream connectivity affects populations. Other species, that are not as widespread, may not be as useful when trying to understand how the obstruction of stream connection affects fish populations because they are not found in all streams and therefore, are less likely to try to move between streams. Paul will use both genetic techniques and radio telemetry to determine how impassable structures are limiting movement and gene flow between stream segments. The results of this study will help managers make more informed decisions in prioritizing remediation of impassable structures.