Some clam juices are high in sodium. Look for brands such as Bar Harbor, Blue Crab Bay, Bookbinder’s, and Look’s clam juice because they are lower in sodium.
Season salmon with salt and pepper. In a nonstick skillet, sprayed with nonstick cooking spray, brown salmon on both sides about 2 minutes. Remove salmon from skillet and set aside. Meanwhile, trim the greens off the fennel and reserve for a garnish. Thinly slice bulb of fennel, discarding the inner core. In a large, deep skillet heat the olive oil over medium heat. Add fennel and cook until tender, about 4 minutes. Add garlic and lightly brown. Add tomato, clam juice, wine, and saffron. Bring to a gentle boil and add salmon fillets. Cover and cook for 8 minutes. Uncover and cook for 1 more minute. Remove salmon to a shallow bowl and turn the heat to medium-high. Reduce tomatoes and fennel broth until thickened, about 5 minutes. Serve broth over fish. Garnish with chopped fennel fronds.