Environmental influences on juvenile Atlantic Croaker (Micropogonias undulatus) growth in the Western Gulf of Mexico

Spatial and environmental variation in finfish growth has important implications for fisheries management. Atlantic Croaker ( Micropogonias undulatus ) is a valuable sportfish and baitfish throughout the Gulf of Mexico and U.S. western Atlantic coast; however, growth throughout the juvenile stage, when most growth occurs, is largely understudied in the Western Gulf of Mexico. Therefore, this study aimed to model Atlantic Croaker young-of-the-year growth, determine spatial growth variation along the Texas coast, and evaluate environmental influences on growth rate. Length frequency data for juvenile Atlantic Croaker was collected from all major Texas bays as part of the Texas Parks and Wildlife Department’s long-term fishery-independent monitoring program from 1990-2023. Multiple growth models were evaluated to compare juvenile growth curves among regions, and generalized additive models assessed the influence of salinity, temperature, turbidity, and dissolved oxygen on growth. Richard’s model provided the best fit for juvenile growth and described clear spatial differences in growth among bays. Growth rate increased substantially from north to south, following trends of increasing salinity and temperature and decreasing turbidity and dissolved oxygen. Salinity and dissolved oxygen were significant predictors of growth in the generalized additive model, with higher salinity promoting faster growth in larger juveniles (approximately ≥ 70 mm). These findings suggest salinity plays an important role in the growth of juvenile Atlantic Croaker and likely contributes to spatial variation in growth along the Texas coast. As anthropogenic effects continuously alter estuarine conditions throughout the Gulf of Mexico, understanding juvenile growth dynamics will be essential for effective management.