AbstractEvaluation and monitoring of stocking effectiveness is essential to make informed fisheries management decisions. Chemical marking, such as oxytetracycline (OTC), is often used for differentiating stocked from wild fish but has inherent error in mark longevity and otolith evaluation. Genetic analysis of recaptures provides a viable alternative. In this study, fingerlings (~50 mm TL) of F1 intergrade Largemouth Bass Micropterus salmoides (Florida Largemouth Bass M. salmoides floridanus × Northern Largemouth Bass M. salmoides salmoides) were marked with OTC via immersion and stocked into the Chickahominy River, Virginia, from 2005 to 2007 and more recently from 2015 to 2017, totaling 595,000 fish. We collected Largemouth Bass in 2015 and 2017 during long‐term monitoring on the tidal portion of the Chickahominy River in Virginia. Fish were retained for aging, OTC evaluation, and genetic analysis. Although precision (i.e., agreement) was high (95%) when comparing the two methods, by establishing a baseline number of known recaptures (N = 19 samples verified by genetics), we determined that detection probability (accuracy) was 63%. Differentiating stocked from wild fish with genetics provides advantages over OTC immersion for stocking evaluations, including potential cost and labor savings. Future studies should routinely incorporate an evaluation of tagging detection rate to accurately adjust percent contribution estimates.