Organismic and Evolutionary Biology Program, University of Massachusetts Amherst, 230 Stockbridge Road, 204C French Hall, Amherst, MA 01003, USA.
US Geological Survey, Leetown Science Center, S.O. Conte Anadromous Fish Research Center, One Migratory Way, Turners Falls, MA 01376, USA.
Biol Lett. 2020 Sep;16(9):20200218. doi: 10.1098/rsbl.2020.0218. Epub 2020 Sep 23.
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 δC stable isotope analyses to investigate predator-prey interactions at a road-stream crossing culvert. Eastern snapping turtles () were found to regularly reside within the culvert to ambush migratory river herring ( 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-溪流交叉口的涵洞可以通过减少溪流宽度和鱼类移动速度来增加鱼类密度，使这些通道成为理想的捕食者伏击地点。在这项研究中，我们使用录像和 δC 稳定同位素分析的组合来调查道路-溪流交叉口涵洞处的捕食者-猎物相互作用。东方 snapping 龟（）被发现经常在涵洞内栖息以伏击洄游的河鲱（ spp.）。居住的鱼类物种对 snapping 龟表现出回避行为，导致这些鱼类没有受到攻击。相比之下，河鲱没有回避行为，在 79%的接近中被 snapping 龟攻击，捕获率为 15%。稳定同位素分析表明，在来自涵洞的海龟中，海龟的饮食明显转向了河鲱的消耗，而在来自非涵洞的个体中没有观察到这种情况。这些发现表明，设计用于允许通行的人为障碍物，如涵洞，可能会通过成为居民和洄游鱼类移动的瓶颈，创造捕食机会。
