There is growing evidence that culverts at road-stream crossings can increase fish density by reducing stream width and fish movement rates, making these passageways ideal predator ambush locations. In this study, we used a combination of videography and δ¹³C stable isotope analyses to investigate predator–prey interactions at a road-stream crossing culvert. Eastern snapping turtles (Chelydra serpentina) were found to regularly reside within the culvert to ambush migratory river herring (Alosa spp.). Resident fish species displayed avoidance of the snapping turtles, resulting in zero attempted attacks on these fish. In contrast, river herring did not display avoidance and were attacked by a snapping turtle on 79% of approaches with a 15% capture rate. Stable isotope analyses identified an apparent shift in turtle diet to consumption of river herring in turtles from culvert sites that was not observed in individuals from non-culvert sites. These findings suggest that anthropogenic barriers like culverts that are designed to allow passage may create predation opportunities by serving as a bottleneck to resident and migrant fish movement.

越来越多的证据表明，道路与溪流交叉口的涵洞可以通过减少溪流宽度和鱼类移动速率来增加鱼类密度，使这些通道成为理想的捕食者伏击地点。在这项研究中，我们结合使用录像和 δ ¹³ C 稳定同位素分析来研究道路-河流交叉涵洞处捕食者-猎物的相互作用。人们发现东部鳄龟（Chelydra serpentina）经常栖息在涵洞内伏击洄游的河鲱（Alosa ）。属）。常驻鱼类表现出对鳄龟的回避，导致对这些鱼类的攻击企图为零。相比之下，河鲱没有表现出回避，在 79% 的方法中被鳄龟攻击，捕获率为 15%。稳定同位素分析发现，海龟饮食明显转变为来自涵洞地点的海龟食用河鲱鱼，而在非涵洞地点的个体中则没有观察到这一点。这些发现表明，像涵洞这样旨在允许通过的人为障碍可能会成为居民和迁徙鱼类运动的瓶颈，从而创造捕食机会。