With the latest reauthorization of the Magnuson-Stevens Fishery Conservation and Management Act (MSA) and the precarious state of many of the nation's fisheries, it has become essential to incorporate uncertainty in the process of setting annual catch limits (ACLs) and annual catch targets (ACTs). The accuracy with which we predict landings can be thought of as management uncertainty, and it can be estimated by comparing the predicted landings intended by a regulation to the fisheries\' actual landings estimates. The National Standard 1 Guidelines for the MSA state that management regulations should take into account management uncertainty when establishing ACLs or ACTs, prescribing more precaution when management uncertainty is high. This study compared pre-season landings predictions of managed fish species in the South Atlantic to post-season estimates and investigated the existence of management uncertainty, and evaluated its magnitude and direction. Results indicate that the magnitude of management uncertainty for some stocks in the region may be significant. It appears that recreational fisheries have significantly greater management uncertainty than commercial fisheries, and that commercial fisheries are often producing landings smaller than intended or predicted. No relationship was found between regulatory mechanism or the magnitude of a fishery and management uncertainty. The study also revealed that documentation of the methodology used to determine preseason catch estimates is often not sufficient to repeat estimation procedures. The results of this study will have immediate and direct utility in the setting of future management regulations, ACLs, and ACTs in the South Atlantic region, and perhaps beyond. / Master of Science