Seafood in the kitchen is almost like French pastry-it is quite a challenge to many cooks. While creating French pastries is difficult and it takes enormous experience and knowhow, preparing good seafood is easy. It takes only some basic knowledge and a little experience.

Here is some additional specific information about each of the 4 species of shellfish that you are likely to find at the fish market:

Abalone is a large single-shelled mollusk with a proportionally large creamy white, firm muscle that has a mild and wonderful flavor. The muscle that cooks commonly cut it into slices as steaks, is tough and rubbery when fresh and needs some tenderizing, either in a tenderizing bath or with a meat mallet.

This mollusk was in high demand in the 1970s and as a result fishermen severely over fished it. It virtually disappeared from markets through the 1980s, but aquaculturing abalone began in the 1990s. You’re still not likely to find it in any but the most exclusive seafood markets. It is a slow-growing mollusk (takes four years to develop 3½ ounces or 100 g of meat), and the appetite for abalone, especially in sushi bars in Japan, is insatiable.

Expect to pay $40 to $50 a pound (half a kilo) (U.S. price in late 1990s), including the shell! Count on 4 to 5 ounces (110 to 140 g) of abalone meat per person. About 30 percent of abalone in the shell is edible meat.

Clam is a bivalve mollusk. This means its shell has two halves, and the muscle that holds them together is the one we love so much. You can buy clams live in the shell, shucked (which means they have been removed from the shell) or pasteurized in cans.

Live is the best choice if you don’t mind the extra work of shucking. Steaming in a large pot loosens the grip of the muscle and the shells fall open. The best indication of a live clam is a tightly closed shell.

The major culinary division for clams is soft-shell and hard-shell (this one is also called quahog). The names refer to the thickness of the shells. Soft-shell varieties have shells so thin that you can push your finger right through them. The hard-shell varieties, on the other hand, are so thick you may need a hammer to break them. The best way to prepare soft-shell clams is to steam or fry them. You can eat small hard-shell clams raw.

If they are large, processors chop or mince them and use them in a preparation like chowder. Different kinds are available in different areas, but within the two major categories, you can substituted them for each other.

Occasionally you come across cockle, a species of clam. It may incorrectly be called winkle, a shortened name for periwinkle, which is an edible snail-like mollusk not commonly available. Cockles are far more popular in Europe and Southeast Asia than in Amercia.

Only 20 to 30 percent of the gross weight of clam in the shell is edible meat, more for larger clams, less for smaller ones. The giant geoduck clam (pronounced GOO-y-duck) for instance, is 70 percent edible muscle.

For most clams, 6 to 8 shells per serving is enough but ask the clerk if you are unfamiliar with the specific clam you are buying. Geoduck, however, has so much meat that count on 5½ to 7 ounces (160 to 200 g) of weight, including the shell, per person. Geoducks are huge, some weigh over 5 pounds (2¼ kg).

Conch (pronounced KONK) is a single-valved mollusk. It is locally available along south Florida shores and in the Caribbean, though you may find it in some restaurants in other areas. It is the large muscle of the foot that is edible, and it needs tenderizing, like abalone, or cooking it as ground meat. The flavor is mild, suitable for salads and chowders. Count on 2 or 3 conchs per serving or, if already shelled, 4 to 5 ounces ( 110 to 140 g) of meat.

Crab is one of the three most popular shellfish consumed. There are 20 commercially significant crabs species, eight of which are common in North America. In some species we use the claw meat mainly. In others, it is the body meat, and in a few it is the leg meat that is prized. Fresh crab is an excellent meat, but the canned variety is in an entirely different league.

Raw crab does not freeze well, so when you see frozen crab, it had been cooked or otherwise processed. Frozen crab can be very good.

The versatility of this shellfish contributes to its popularity. Different species have different textures, and some lend themselves more to certain cooking methods than others. In the kitchen, crab is in three main categories:

¨ Lump meat is a solid chunk of meat from the crab’s body. Use it in dishes where appearance is important.

¨ Flake meat is smaller pieces from other parts of the body, not as wholesome in looks as lump meat but still suitable for most crab recipes.

¨ Claw meat comes in still smaller pieces. Use it when appearance is not critical, such as in soups and in some salads.

Blue crab from the eastern U.S. is the most common species. Like all crabs, blue crab sheds its shell when it runs out of room. The new shell grows in just a few days, but while that is taking place, the crab is very vulnerable to predators. During those few naked days the rest of the crab, including the meat, also grows very quickly.

This is the ideal time for human predators to nab them, having extra meat and very little shell to fight on the plate. These are called soft-shell crabs. Experienced crabbers and distributors separate out crabs that are about to shed their shells

(they tell by a reddish coloration) and market them at premium prices as soon as the old shell comes off. About 25 percent of the total weight of a crab is edible meat. In the shell, 1 to 1¼ pound (450 to 570 g) of live crab per person is a generous serving, or 4 to 5 ounces (110 to 140 g) of crab meat if you buy it shelled.