Reproductive physiology in eastern snapping turtles (Chelydra serpentina) exposed to runoff from a concentrated animal feeding operation.

The eastern snapping turtle (Chelydra serpentina) is widely distributed throughout the eastern and central US and is a useful model organism to study land-use impacts on water quality. We compared the reproductive condition of turtles from a pond impacted by runoff from land applied with animal manure from a concentrated animal feeding operation (CAFO) relative to animals from a control pond. Turtles from the CAFO site were heavier and had higher plasma concentrations of vitellogenin (VTG, mean ± SE; females; 859 ± 115 vs. 401 ± 127 ng/mL from controls) and testosterone (T, males; 39 ± 7.0 vs. 3.8 ± 6.9 ng/mL from controls). No VTG was detected in males. Body mass was positively correlated with VTG and T. Our results suggest that nutrient pollution of the CAFO pond indirectly resulted in higher plasma VTG in females and T in males because of an increase in body mass. The population-level consequences of these effects are not clear, but could result in females producing larger clutches.