Your best bet is to visit your local tackle shop and purchase your bait. If you choose to dig or trap your own crabs, be aware that many towns & villages on Long Island require you to purchase a permit for harvesting any species of crab, even if you are using them for bait. For about $4 bucks, you can buy a pint of fiddler crabs. For a buck or two more, you can purchase a dozen nice-sized green crabs. Trust me, when the temps start to drop, the last thing you want to be doing is wasting your time catching crabs when you can be out fishing.