Some reading material for you
http://www.bluecrab.info/forum/index.php?topic=24801.0also,
A lobster/crab permit is required of all persons to fish for lobster and edible crabs in coastal waters. To sell lobster and crabs, a commercial lobster/crab permit is required. However, no permit is required to take edible crabs for use by immediate family, provided that the number of crabs does not exceed fifty(50) in one day and that no pots or traps are used.
found at
http://www.mass.gov/dfwele/dmf/commercialfishing/lobsters.htm