Oysters have experienced severe declines from overharvesting, disease, and environmental degradation. For the successful renewal of populations, oyster larvae require suitable water parameters and a well-balanced, but lipid-rich diet. Water samples were taken and environmental data measured over six historically abundant and present oyster reefs in the Western Mississippi Sound during the 2024 spawning season. The water samples were analyzed for seston food quality in terms of total lipids, proteins, and carbohydrates. The seston was also size-fractionated, with measures of lipid, protein, and carbohydrate obtained for a series of size divisions set at 20, 10, 5, and 2 μm. Water temperature peaked in late August, at 31 °C, and then declined through October. Salinity remained low, 2.93 to 8.14‰, until late June, then quickly increased to a maximum of 25‰ in late August, declining thereafter. Dissolved oxygen remained high, 5 to 9 mg/L, with the lowest values in the summer months. Particulate matter and particulate organic matter followed a similar pattern, spiking in late June and early August. Protein concentrations remain around 1-2 mg/L except in late June when concentrations dramatically increased, shadowing the first spike in particulate organic matter. Carbohydrate concentration increased through the summer, peaking in August at over 1 mg/L, at the same time as the second peak in particulate matter. Lipid concentration was generally high from May to June, then declined sharply in the following months. Understanding how food quality fluctuates spatially and temporally has critical implications for larval success. The environmental data and food quality parameters will be input into a larval performance model to estimate the influence of food quality available during the 2024 spawning season on larval survival; comparison will be made between model predictions and the observed timing and intensity of larval settlement on the reefs.