1. Preheat oven to 400°F.
2. Lightly season the black cod fillets with kosher salt and black pepper.
3. Lightly dust the fillets in flour, shaking off excess. In a large cast iron skillet, over medium-high heat, preheat the vegetable oil until just smoking.
4. Sear the fillets on the side that was connected to the bone until lightly browned, about five minutes. Using a wide stainless steel spatula, turn the fillets over, and transfer to oven to cook for about 5 minutes more.
5. In a large mixing bowl, toss the 4 fresh herbs. To serve, divide the herb salad equally among four large, warm plates.