Examining the Influence of Genetics on Migration and Habitat Preference in Callinectes sapidus

The Atlantic blue crab (Callinectes sapidus) is an ecologically and commercially fundamental species. At various life stages, crab migrations are influenced by environmental cues including light, salinity, chemistry, depth change, turbulence, and water flow. Though adult and juvenile blue crabs live in estuaries, the larval stages of all genotypes are mixed and develop in the coastal ocean. The objective of this study is to determine whether blue crab habitat use, and migration patterns are reflected in the mitochondrial cytochrome c oxidase 1 (CO1) gene region. This will be determined by examining resident blue crabs from Carrot Island, NC (29-35 PSU) and Lake Mattamuskeet, NC (0 PSU), and spawning female crabs from Beaufort Inlet, NC (29-34.5 PSU). Carrot Island had a relatively lower haplotype diversity (0.7260 ± .03900) compared to Beaufort Inlet (0.9841 ± .00021) and Lake Mattamuskeet (0.94154 ± .00118). Significant pairwise differences were found between Carrot Island and Beaufort Inlet (Nm = 0.26018, p < 0.001), as well as between Carrot Island and Lake Mattamuskeet (Nm = 0.19482, p < 0.001), indicating a lack of gene flow. Overall, blue crabs from Carrot Island had high, significant genetic differentiation when compared to crabs from both Beaufort Inlet (Fst = 0.11830, p < 0.001) and Lake Mattamuskeet (Fst = 0.09689, p < 0.001). These results support the hypothesis and provide initial evidence that genetics influence habitat preference and migration patterns in blue crabs.