Strontium/Calcium Ratios in Robust Redhorse Otoliths

David J. Coughlan
Duke Power Company Huntersville, NC (704) 875-5236 (704) 875-5032 djcoughl@duke-energy.com

W. Mark Rash
Duke Power Company Huntersville, NC (704) 875-5451 (704) 875-5032; wmrash@duke-energy.com

Dr. Karin Limburg
State University of New York College of Environmental Science & Forestry 133 Illick Hall Syracuse, NY 13210 (315) 470-6741 (315) 470-6934

The robust redhorse (Moxostoma robustum) is a rare catostomid fish that is currently found only in Georgia. Biologists surmise its historic range was the Atlantic slope from Georgia to North Carolina. Numerous, though not exhaustive, surveys in this range have collected several catostomid species though robust redhorse have yet to be collected above the Fall Line. The authors present some information on saline water use by catostomids that may indicate why current robust redhorse populations have not been found above the first impassable barrier.

Otolith microchemistry is an analytical technique that may answer the question of saltwater exposure by robust redhorse with material already 'on-hand'. The ratio of strontium to calcium (Sr/Ca) in fish otoliths has demonstrated exposure to saline waters for various fish species and was employed in this study. Preliminary analyses of Sr/Ca ratios in robust redhorse otoliths are presented with implications for future research.