SREL Reprint #3637

Short-term exposure to elevated suspended sediment increases oxygen uptake of gilled larval Eastern Hellbender (Cryptobranchus alleganiensis) salamanders

S.D. Unger1, R.R. Goforth2, O.E. Rhodes Jr.3, and T.M. Floyd4

1Biology Department, Bridges Science Building, Wingate University, Wingate, NC 28174, USA
2Department of Forestry and Natural Resources, Purdue University, 195 Marsteller Street,
West Lafayette, IN 47907-2033, USA
3Savannah River Ecology Laboratory, P.O. Drawer E, Aiken, SC 29802, USA
4Wildlife Resources Division, Wildlife Conservation Section, Georgia Department of Natural Resources,
116 Rum Creek Drive, Forsyth, GA 31029, USA

Abstract: Freshwater ecosystems are increasingly impacted by anthropogenic elevated levels of suspended sediment that may negatively affect aquatic organisms, including salamanders. Although increasing fine sediment in streams has been suggested as a reason for population declines, to date no study has empirically assessed the effect of suspended sediment on gilled larval Eastern Hellbenders (Cryptobranchus alleganiensis (Sonnini de Manoncourt and Latreille, 1801)), a critical life-history stage and a species of conservation concern. We used custom respirometers to elucidate effects of suspended sediments on larval Eastern Hellbender oxygen uptake in trials conducted in situ in Georgia (USA) streams. Mean oxygen uptake increased and was significantly higher in trials when larval salamanders were exposed to suspended sediment (mean = 5.06 mg O2/L for 800 mg/L of sediment treatment vs. 2.25 mg O2/L for 0.00 mg/L of sediment control). This may indicate elevated physiological stress in response to short-term exposure to suspended sediments. Qualitatively, individuals in both groups exhibited rocking behavior in response to low oxygen (hypoxia), albeit at different frequencies (sediment exposure = 7.6 rocks/min and control = 2.1 rocks/min). Larval salamanders may be able to temporarily compensate for low oxygen through increased rocking behavior when high suspended sediment loads are present, with future respirometry research needed.

Keywords: respirometry, sedimentation, salamander conservation, physiology, amphibian, hypoxia, Eastern Hellbender, Cryptobranchus alleganiensis

SREL Reprint #3637

Unger, S. D., R. R. Goforth, O. E. Rhodes Jr., and T. M. Floyd. 2021. Short-term exposure to elevated suspended sediment increases oxygen uptake of gilled larval Eastern Hellbender (Cryptobranchus alleganiensis) salamanders. Canadian Journal of Zoology 99(6): 531-538.

This information was provided by the University of Georgia's Savannah River Ecology Laboratory (srel.uga.edu).