Salmon has tender flesh, and to prevent it from sticking to the grates, there are a couple of things to keep in mind. First, make sure the grates are nonstick. You can achieve this by rubbing the grates with half of a potato, which helps create a nonstick surface. Second, ensure that the salmon fillets are well coated with the spice mix. This creates a layer between the flesh and the grates, reducing the chances of the fish sticking to the grill.