Striped Bass with Salsa Verde

Name: Striped Bass with Salsa Verde
Ingredients: 1 lemon; 1 whole cleaned striped bass (about 2 lbs.); 3⁄4 cup plus 1 tbsp. extra-virgin olive oil; Kosher salt and freshly ground black pepper, to taste; 1⁄2 cup chopped flat-leaf parsley leaves, stems reserved; 2 tbsp. chopped tarragon leaves, stems reserved; 3 inner ribs celery, halved crosswise; 1⁄2 cup chopped celery leaves; 1⁄4 cup capers, rinsed and chopped; 1⁄4 cup crème fraîche; 4 tsp. Dijon mustard; 6 scallions, white and light green parts only, thinly sliced; Large pinch of crushed red chiles