The diversion of freshwater from the Mississippi River is intended to mitigate saltwater intrusion from the Gulf of Mexico and to lessen the concomitant loss of wetland areas. Though effective, freshwater diversion can affect wildlife and habitat; therefore, prediversion and postdiversion data collections are necessary to identify effects. The Davis Pond freshwater diversion area is located between the Mississippi River and Bayou Lafourche and extends to Barataria Bay Basin, Louisiana. Results and interpretations from the prediversion biomonitoring done in 2001 - which included data on fish, eagles, and bivalves - are presented in the U.S. Geological Survey (USGS) Scientific Investigations Report 2008-5067, "Davis Pond Freshwater Prediversion Biomonitoring Study: Freshwater Fisheries and Eagles." The postdiversion data generated approximately 6 years later from the sampling of fish whole bodies are presented here in this USGS Data Series. An accompanying log of postdiversion study site photographs was also produced in USGS Data Series 605, "Photographic Images Captured While Sampling for Bald Eagles near the Davis Pond Freshwater Diversion Structure in Barataria Bay, Louisiana (2009-10).This table presents the results of statistical analysis of variance of organic contaminants in fish sampled pre- and postdiversion of Davis Pond. Data collected consist of measurements of organic contaminants detected in largemouth bass, blue catfish and striped mullet samples collected in 2001 (prediversion) and 2007-2009 (6-8 years postdiversion). Total amounts of organic contaminants were compared using two-way and three-way analysis of variance (ANOVA) tests. Organic contaminants tested for include aliphatic hydrocarbons (AHs), polycyclic aromatic hydrocarbons (PAHs), organochlorines (OCs), DDT, DDE, and polychlorinated biphenyls (PCBs). A four-site analysis was performed to compare levels of contamination in fish drawn from the Mississippi River, and those collected from three marsh sites (Lake Cataouatche, Bayou Couba, and Lake Salvador).