High Genetic Diversity and Implications for Determining Population Structure in the Blue Crab Callinectes sapidus

ABSTRACT Understanding the population structure of a commercially fished species and how those populations change over time is essential for proper management. Although the blue crab Callinectes sapidus (Rathbun, 1896) covers a large geographic range spanning two continents and several distinct ecosystems, there are no clear morphological characters and a paucity of genetic data that can be used to distinguish populations within and among management areas. In this study, diversity indices were calculated for four loci in the mitochondrial genome of C. sapidus using specimens collected from the Rhode River in Maryland during the summers of 2003 to 2005. The locus with the highest diversity, which occurs within the open reading frame of the nad2 mitochondrial gene, was then used as a marker to determine population structure for samples collected from the Atlantic locations of the Chesapeake Bay; Raleigh, North Carolina; Meadowlands and Tuckerton, New Jersey; and Massachusetts, as well as locations in the Gu...