Entry #72

Oregon’s native turtles are Conservation Strategy species of concern due to habitat loss and degradation and threats from invasive species, including Red-eared Sliders (Trachemys scripta elegans). Although population trends have been documented in both native and invasive turtles in Oregon, the physiological health of turtles, and how this might be impacted by habitat quality has been less well-studied.  In this study, we examined how common water quality metrics including temperature, pH, and turbidity, affect baseline physiological stress (corticosterone levels), immune function, and capture success rate in both native Western Painted Turtles (Chrysemys picta bellii) and invasive Red-Eared Sliders at Minto Brown Island Park in Salem, OR, from July-September 2024. We used baited hoop nets and recorded water temperature, pH, and turbidity at the time of capture. A blood sample was taken within 5 minutes of capture of each turtle to accurately examine baseline corticosterone levels and immune function (bacterial killing ability and heterophil: lymphocyte ratio). Most of the water quality metrics did not predict turtle capture, corticosterone levels, or immune function. However, water temperature positively predicted turtle capture, with a small positive trend of increased corticosterone with increased temperature. These preliminary findings contribute to broader conservation efforts by enhancing our understanding of the factors that affect freshwater turtle capture, as well as how water metrics may influence physiological health in these species.