1. Shell and devein shrimp, leaving tail part of shell on; rinse. Scrub clams and mussels with running cold water to remove any sand; remove beards from mussels. Cut snapper into 2-inch chunks.

2. Peel and cut each potato into quarters. Cut zucchini into bite-size chunks. Mince onion and garlic.

3. In 4-quart saucepan, cook potatoes with water to cover until almost tender, about 15 minutes. Add zucchini; cook until just tender, about 5 minutes. Drain.

4. Meanwhile, in 8-quart Dutch oven over medium heat, in hot salad oil, cook onion until tender. Add garlic, chicken broth, clams and mussels; heat to boiling. Cover and cook about 5 minutes, removing them to large bowl as shells just open.

5. To broth in Dutch oven, add tomatoes with their liquid, wine, sugar and salt; heat to boiling. Stir in clams, mussels, potatoes, zucchini, shrimp, and red snapper; heat to boiling. Reduce heat to medium; cook uncovered, until shrimp turn opaque and snapper flakes when tested, about 5 minutes. Sprinkle with chopped basil. Makes 4 main-dish servings.