Steamed to a brilliant red, these blue crabs are ready to eat at Captain White’s, one of four businesses at the Maine Avenue Fish Wharf. In winter, the off-season for Chesapeake Bay crabs, D.C. seafood businesses obtain crabs from the Carolinas and Louisiana. That’s happening a lot these days: Many Chesapeake Bay crabs never grow larger than a bottle cap, before they’re gobbled up by a thriving population of Chesapeake rockfish, or striped bass, which have rebounded heartily from their low numbers a decade ago. Consequently, the price of ever popular crabs is on the rise.