Preparation Sauté bacon in large pot over medium-high heat until crisp, about 10 minutes. Transfer 1/3 of bacon to bowl. Add onion to remaining bacon and drippings in pot; sauté 5 minutes. Add potato and fennel bulb; sauté 5 minutes. Add wine; bring to boil. Add broth, clam juice, tomatoes with juices, thyme, and reserved fennel fronds; bring to boil. Reduce heat and simmer until potato is tender, about 5 minutes. Add halibut and shrimp to pot; cover and cook until opaque in center, about 3 minutes.
Preparation Sauté bacon in large pot over medium-high heat until crisp, about 10 minutes. Transfer 1/3 of bacon to bowl. Add onion to remaining bacon and drippings in pot; sauté 5 minutes. Add potato and fennel bulb; sauté 5 minutes. Add wine; bring to boil. Add broth, clam juice, tomatoes with juices, thyme, and reserved fennel fronds; bring to boil. Reduce heat and simmer until potato is tender, about 5 minutes. Add halibut and shrimp to pot; cover and cook until opaque in center, about 3 minutes.