Post-glacial population expansion of the Monterey Spanish mackerel Scomberomorus concolor in the Gulf of California

The level of genetic homogeneity and demographic history of the Monterey Spanish mackerel Scomberomorus concolor was assessed by analyses using sequences of the mitochondrial (mt)DNA-control region of samples from the two oceanographic regions of the Gulf of California in order to define the stock structure for this exploited vulnerable species. The data were consistent with a single homogeneous population and revealed the hallmark of fluctuations in population size; these fluctuations appear to have occurred during glacial events of the middle to late Pleistocene, which may in turn be related to the colonization and expansion of S. concolor populations in the gulf.