Smoky Salmon and Fennel Chowder

Name: Smoky Salmon and Fennel Chowder
Ingredients: 1 tablespoon olive oil; 1 tablespoon unsalted butter; 1 medium yellow onion, chopped; 1 medium fennel bulb, fronds removed and reserved, halved lengthwise, thinly sliced; Salt; 2 tablespoons all-purpose flour; 4 cups water; 1/2 pound yukon gold potatoes cut into 1/2-inch pieces (peeling optional); 1 pound salmon filet, skin and pin bones removed, cut into 1/2-inch pieces; 6 ounces warm smoked salmon, flaked; 1 cup heavy cream; 1 teaspoon freshly ground black pepper