Whether steak and lobster or linguine and clams, shellfish is a popular choice.

Shellfish comprise two main categories: crustaceans and mollusks. I will concentrate on crustaceans and mollusks separately in my next columns.

All shellfish are invertebrate, meaning they do not have an internal bone structure as do vertebrates like fish. Almost all shellfish have hard outer shells that protect soft bodies. Crustaceans include crabs, lobsters, shrimp, crayfish, etc.

Buying shellfish live is almost always preferred, but it's not always an option. When live is an option, it is usually only crabs and lobsters that are available.

The most common way to cook a live crab or lobster is to submerse it headfirst into a pot of boiling water to kill it instantly.

Crabs are boiled for about 6-10 minutes depending on their size, and lobsters are usually cooked 5-6 minutes per pound.

Trying to extract raw flesh from a crab is more difficult than cooked.

An option for killing a lobster is to hold it down firmly on a cutting board and plunge the tip of a chef's knife into the head. It should be done immediately before cooking, to ensure optimal freshness and flavour, as the rule of thumb for raw crab or lobster is to cook it live. Raw flesh of crabs and lobsters deteriorates very rapidly.

Lobsters are also very tasty if split in half and opened up, brushed with oil, lemon juice, and seasonings, and then grilled on the barbecue. Cut it right through, to serve as two halves, or cut it from the underside, but not all the way through the top shell, to serve as a whole split lobster.

To prepare it split whole, weigh down the tail, as it will curl up and lose contact with the grill, or cut the tail section right through while leaving the body halves connected by the top shell. This way you can curl the tail to the sides of the lobster.

With either grilling option, the large claws should be cracked beforehand, to assist in cooking the claw meat at the same speed as the exposed body and tail flesh.

Crabs' and lobsters' stomachs are located just behind the eyes, and should be removed and discarded before eating. Crabs' feathery gills, on each side of the body under the shell, are also discarded.

Chef Dez is a food columnist and culinary instructor in the Fraser Valley. Visit him at www.chefdez.com. Send questions to dez@chefdez.com or to P.O. Box 2674, Abbotsford, B.C. V2T 6R4