California Cioppino

2 freshly cooked whole crabs,
    approximately 1 1/2 to 2 pounds each
24 clams, well scrubbed
3 cups dry white wine
1/3 cup olive oil
1 medium onion, finely chopped
3 large cloves garlic, minced
1 green bell pepper, coarsely chopped
2 pounds fresh tomatoes, peeled, seeded, and chopped
3 ounces tomato paste
1 teaspoon freshly-ground pepper
1/2 teaspoon dried Mexican oregano
1/2 teaspoon dried basil, or 1 tablespoon finely chopped fresh basil
2 pounds fresh white fish such as sea bass, rock cod,
    halibut or ling cod, cut into large pieces
3/4 pound scallops
3/4 pound raw shrimp, peeled and de-veined
Chopped fresh parsley

Remove the legs and claws from the crab and break the body in half, reserving as much of the soft, mustard-colored center (crab butter) as possible. Set crab pieces aside and force the crab butter through a sieve into a small bowl. Set aside.

Place the clams in a pan, add 1 cup of wine, and steam, covered, over medium heat for 4 to 6 minutes or until clams open. Remove clams, discarding any that do not open. Strain the stock through cheesecloth and reserve.

In an 8-quart heatproof casserole or a kettle, heat the oil. Add the onion, garlic and bell pepper and saut