Lots of local [Maryland] diners have a taste for blue crab. Lots of chefs and restaurateurs have good crab-based recipes. Lots of home cooks enjoy hosting crab-related events and have their own preferred methods of crab preparation. Over time, as the region's population has grown, this local crab economy's ferocious demand for crab has outstripped the local ecosystem's [Chesapeake Bay] sustainable level of crabbing. So the market demands that crabs [from Louisianna] be shipped not to crabless parts of America but to America's crab-production heartland [Maryland]—the place where the secondary and tertiary elements of the crab economy are in place, and the finished product has maximum value.
What's next? Are they going to tell me that Natty Boh is produced in North Carolina.
Oh, the horror!
Increased demand causes increases in quantity supplied. When the local economy can no longer supple the quantity demanded, non-local producers will increase the quantity supplied (because the relative willingness to pay is higher).