Assessing the spatio-temporal genetic stock structure of red drum (Sciaenops ocellatus) across the northern Gulf of Mexico

Understanding population structure is important and necessary in order to effectively manage fisheries. Although relatively little is known about the population structure of stocks of many important marine species, especially in the Gulf of Mexico, molecular technologies allow for a more comprehensive assessment. The red drum (Sciaenops ocellatus) is a marine-estuarine fish that is of great recreational importance in estuarine waters of many Northern Gulf coast states. This study incorporated twenty microsatellite markers (short stretches of tandomly repeated nucleotides in a bi-parental fashion commonly used as markers in fisheries science) and a 367bp fragment of mitochondrial DNA (D-Loop region) to examine spatial aspects of stock structure of red drum populations across the major estuaries and offshore areas of the Northern Gulf of Mexico from Texas to Florida. Data from both inshore (juveniles/sub-adult) populations and offshore (adult) populations were gathered. Migration patterns, genetic diversity, and genetic structure will be compared and examined between the inshore and offshore populations. Furthermore, temporal changes in genetic structure and effective population size will be examined (pre vs. post oil spill) to investigate the potential genetic impacts of the 2010 Deepwater Horizon (DWH) oil spill on inshore population structure in Louisiana waters. Red drum exhibited no population structure along the Northern Gulf of Mexico inshore and offshore and showed high levels of connectivity among populations. There was no observable impact from the DWH oil spill on red drum in terms of genetic diversity, population structure, and migration patterns.