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Wait and snap: eastern snapping turtles (Chelydra serpentina) prey on migratory fish at road-stream crossing culverts

September 23, 2020

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.

Citation Information

Publication Year 2020
Title Wait and snap: eastern snapping turtles (Chelydra serpentina) prey on migratory fish at road-stream crossing culverts
DOI 10.1098/rsbl.2020.0218
Authors Derrick James Alcott, Michael Long, Theodore R. Castro-Santos
Publication Type Article
Publication Subtype Journal Article
Series Title Biology Letters
Series Number
Index ID 70222610
Record Source USGS Publications Warehouse
USGS Organization Eastern Ecological Science Center