Place berries in a small saucepan and heat on medium-low heat. Crush berries with a spoon (or potato masher) to release juices. Cook until the liquid reduces by half (about 1/2 hour), stirring often enough to keep from burning.
You can add 1 tsp sugar to the sauce if you want to, but it isn't necessary.
Meanwhile, salt the non-skin side of the salmon fillets and then baste with olive oil. Grill on low heat until meat flakes easily.