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Suppressing bullfrog larvae with carbon dioxide

Mark Abbey-Lambert·Andrew Ray·Megan J. Layhee·Christine L. Densmore·Adam Sepulveda·Jackson A. Gross·Barnaby J. Watten
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Abstract

Current management strategies for the control and suppression of the American Bullfrog ( Lithobates catesbeianus = Rana catesbeiana Shaw) and other invasive amphibians have had minimal effect on their abundance and distribution. This study evaluates the effects of carbon dioxide (CO 2 ) on pre- and prometamorphic Bullfrog larvae. Bullfrogs are a model organism for evaluating potential suppression agents because they are a successful invader worldwide. From experimental trials we estimated that the 24-h 50% and 99% lethal concentration (LC 50 and LC 99 ) values for Bullfrog larvae were 371 and 549 mg CO 2 /L, respectively. Overall, larvae that succumbed to experimental conditions had a lower body condition index than those that survived. We also documented sublethal changes in blood chemistry during prolonged exposure to elevated CO 2 . Specifically, blood pH decreased by more than 0.5 pH units after 9 h of exposure and both blood partial pressure of CO 2 (pCO 2 ) and blood glucose increased. These findings suggest that CO 2 treatments can be lethal to Bullfrog larvae under controlled laboratory conditions. We believe this work represents the necessary foundation for further consideration of CO 2 as a potential suppression agent for one of the most harmful invaders to freshwater ecosystems.

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Mark Abbey-Lambert, Andrew Ray, Megan J. Layhee, Christine L. Densmore, Adam Sepulveda, Jackson A. Gross, Barnaby J. Watten. 2014. Suppressing bullfrog larvae with carbon dioxide. https://doi.org/10.1670/12-126

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