Pork is high in calories and shrimp has 76% less calories than pork - pork has 297 calories per 100 grams and shrimp has 71 calories. For macronutrient ratios, shrimp is much heavier in protein, heavier in carbs and much lighter in fat compared to pork per calorie.
Shrimp is high in cholesterol, but it's important to look at your overall diet. You are right, shrimp is a low-fat, lower-calorie source of protein. Shrimp is certainly lower in fat and calories than lean beef: Three ounces contains 31 grams of protein, eight grams of total fat, and 3.2 grams of saturated fat.