Those more familiar with cooking meat than seafood should simply remember that the rules are turned upside down. Unlike with meat, seafood does not need to be tenderized by cooking. In fact, cooking seafood too long has the opposite effect, making it tougher as its natural juices are lost.
When cooking whole fish, steaks or fillets, cook for 10 minutes per inch, as measured at the thickest part. For less than an inch, shorten the time accordingly; i.e. half-inch, five minutes.
Color is the best sign for determining the cooking time for shrimp, lobster and scallops. Shrimp and lobster turn red and the flesh becomes white. Scallops firm up and turn a milky white color
The shells of other shellfish are the best gauges. Clam, mussel and oyster shells will open when they are done cooking. Those that stay closed should not be used.
When buying shellfish, make sure they are coming only from reputable sources. Shellfish bought live should be kept alive and refrigerated properly until ready to prepare. Live clams, mussels and oysters should be stored in well-ventilated refrigeration, not air-tight bags or containers.
Differences in nutrition
Remember that how seafood is prepared can make all the difference when counting calories and fat.
A recent article in the Dallas-Forth Worth Star-Telegram gave the following examples:
Two cups of Manhattan clam chowder have 256 calories, 8 grams of fat, 32 grams of carbs and 14 grams of protein. By comparison, New England clam chowder has 542 calories, 40 grams of fat, 29 grams of carbs and 16 grams of protein. Lobster bisque weighed in at 710 calories, 58 grams of fat, 32 grams of carbs and 16 grams of protein.
While shrimp is typically low-calorie, not so when served with scampi sauce. A typical shrimp scampi dish (eight shrimp with pasta and sauce) contains 830 calories. An eight-ounce broiled halibut, by comparison, has 317 calories.
Finally, what you put on your fish makes a difference, too. One tablespoon of tartar sauce, with its mayonnaise base, has 74 calories and 7.5 grams of fat. The same amount of cocktail sauce, by comparison, has 15 calories and 0.1 gram of fat.