When clam processing companies turn the natural product into food for canning, they split the clam into two parts. What we know as the "tongue" has the most meat in it. The soft remains inside the shell are the "belly." The manufacturers freeze the bellies and sell them to bait wholesalers. Some bellies, however, are reaching the food market as with some restaurants frying and selling them.
Bait on a Hook
If you're using clams for bait, the tongue is the more useful part to use on a hook. The meat of the tongue is tougher, and it will hold onto the hook longer. If you're fishing in choppy waters or going after fish the size of a bass or larger, clam tongues come in handy. The bellies, on the other hand, are too soft to be useful on a hook. After more than one bite, even in calm waters, bellies can come off hooks easily. In rougher waters, and with bigger fish, your quarry can get away with the belly meat fairly easily without getting hooked.
Bait as Chum
Rich Johnson with The Fishing Line is one outdoor sports writer who recommends chum as the better way to use clam bellies as bait. If you drop anchor near the banks of a marsh or under a bridge and set up shop, you'll see a lot of bass coming to feast. You can set the bellies out in a chum pot, or you can squeeze the bellies right out into the water.
Fried Clam Bellies
Some Asian restaurants serve clam bellies as an appetizer. When deep-fried, they have the same texture as pork bellies, although the flavor of clam is richer. According to food writer Hugh Merwin, fried clam bellies go well on sandwiches or in meal-sized baskets. They are chewier and have a bit rougher texture than the tongue, which is the more commonly served part of the clam. While they look similar to fried calamari, you'll find that the calamari has a slightly smoother texture going down. Tartar or cocktail sauce are the two most common accompaniments.
Clam Bellies in Soups and Appetizers
The Dean & Deluca gourmet grocer lists clam bellies as an option in their clam chowders; fresh, they can be a fine substitute for whole clams. Renowned seafood restaurants such as Gage & Tollner have long served clam bellies as appetizers, most commonly either broiled or baked, on buttered toast or still on the half-shell.