Nutrition Breakdown. A serving of salmon is 2 to 3 ounces. A salmon steak is usually between 4 and 6 ounces, or about two servings. Like other fish, salmon contains protein. According to the USDA, women should get about 5 ounces of protein daily; men, 6 ounces; and children, 2 to 5 ounces, depending on age. Salmon is high in Omega-3 fatty acids, which are good for your heart.