Environmental Factors and Individual Characteristics Influencing Mussel Survival During a Dewatering Event

Jonathan M. Miller^1,*, Nguyen Tien Anh Quach^1,2,3, Meet Patel^1,4, and Alban Guillaumet¹

¹Department of Biological and Environmental Sciences, Troy University, Troy, AL 36082.²Department of Biological Sciences, Towson University, Towson, MD 21252.³Current address - Department of Geography, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599. ⁴Current address - Department of Biology, University of Kentucky, Lexington, KY 40506. *Corresponding author.

Southeastern Naturalist, Volume 25, Issue 2 (2026): 201–221

First published early online: 31 May 2026

Abstract
We used a 13-week drawdown at Alabama’s Gantt Reservoir to study the consequences of severe drought and dewatering on the survival of a freshwater mussel, Elliptio pullata (Gulf Spike). Once a week, we selected 50 cm × 50 cm soil quadrats at random from 3 different depth zones and excavated and searched for mussels. We collected a total of 875 live or fresh-dead Gulf Spike mussels in 228 unique quadrats. Generalized linear mixed models revealed that survival declined sharply over time, with ~82% live mussels on week 1 and only ~12% on week 13. Survival probability was greater for intermediate-sized mussels, when mussels were buried in sediment, cover or shading was present nearby, and/or quadrat moisture was higher. Thus, it may be that timing controlled drawdowns to coincide with periods of high soil moisture could improve mussel survival, especially in areas that provide cover or refuge.

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