| Summary: | Two prevalent bacterial diseases in catfish aquaculture are enteric septicemia of catfish and columnaris disease caused by <i>Edwardsiella ictaluri</i> and <i>Flavobacterium covae</i>, respectively. Chronic and recurring outbreaks of these bacterial pathogens result in significant economic losses for producers annually. Determining if these pathogens can persist within sediments of commercial ponds is paramount. Experimental persistence trials (PT) were conducted to evaluate the persistence of <i>E. ictaluri</i> and <i>F. covae</i> in pond sediments. Twelve test chambers containing 120 g of sterilized sediment from four commercial catfish ponds were inoculated with either <i>E. ictaluri</i> (S97-773) or <i>F. covae</i> (ALG-00-530) and filled with 8 L of disinfected water. At 1, 2, 4-, 6-, 8-, and 15-days post-inoculation, 1 g of sediment was removed, and colony-forming units (CFU) were enumerated on selective media using 6 × 6 drop plate methods. <i>E. ictaluri</i> population peaked on Day 3 at 6.4 ± 0.5 log<sub>10</sub> CFU g<sup>−1</sup>. Correlation analysis revealed no correlation between the sediment physicochemical parameters and <i>E. ictaluri</i> log<sub>10</sub> CFU g<sup>−1</sup>. However, no viable <i>F. covae</i> colonies were recovered after two PT attempts. Future studies to improve understanding of <i>E. ictaluri</i> pathogenesis and persistence, and potential <i>F. covae</i> persistence in pond bottom sediments are needed.
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