Preheat the oven to 180 degrees and line a baking sheet with parchment paper. Rinse the broccoli and cauliflower and pat the florets dry with paper towels. Mix the Celtic sea salt, turmeric and black pepper together in a small bowl.
Add the vegetables to a bowl, add the olive oil and half of the spice mixture and toss well. Spread the seasoned broccoli and cauliflower in a single layer on the baking sheet. Pat the salmon fillet dry and rub the fish with the remaining spice mixture. Place the salmon next to the vegetables on the baking sheet.
Slide the baking sheet into the middle of the oven. Roast the salmon and vegetables until cooked through in 15 minutes. The fish is done when it is still light pink inside and the vegetables have light roasted edges.
Remove the baking sheet from the oven. Divide the salmon fillet and roasted vegetables onto a plate and serve immediately.