Characterizing the Genetic Population Structure of Spotted Seatrout (Cynoscion nebulosus) Along the Southeast United States

Spotted seatrout, a recreationally important fish in SC, has recently suffered substantial population declines during the cold winters of 2000, 2009, and 2010 when water temperatures dropped substantially below long term averages.  These winter-kills appear to result in population bottlenecks and their repetitive occurrence over a short time scale has prompted the SCDNR to consider a stock enhancement program.  Prior to implementation of any management tactics, a full understanding of the population structure is required.  The first goal of my thesis research is to determine the genetic population structure across eight estuaries along the southeast U.S. spanning NC to GA using a suite of 13 microsatellite markers. Results suggest significant population differentiation between fish in NC compared to SC and GA.  Although we see a significant break in gene flow between these areas, the overall pattern throughout the sampling range represents a gradient in genetic diversification with the degree of geographic separation.  A lack of appropriate habitat between SC and NC is likely driving the differences as some gene flow is still occurring across the barrier. The use of a powerful suite of markers has allowed higher structure detection than previous projects, which will improve future management of spotted seatrout in SC.