During the past 30 years, shellfish has become more and more popular with a growing abundance of available choices. Today squid, oysters, mussels, and other varieties of shellfish that were once considered ethnic or exotic are as common as shrimp on menus and in local markets.

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Shellfish cookery is basically simple. Success depends more on the quality of the ingredients than on the talents of the cook. This article will provide a few guidelines to help you select the best shellfish and store it properly.

Shellfish Varieties

Despite the many types of shellfish on the market, they are really separated into only two categories -- crustaceans and mollusks.

Crustaceans have elongated bodies with jointed, external shells that are periodically shed as they grow. Crab, lobster, and shrimp are examples of crustaceans.

Mollusks are invertebrates with soft, tender bodies that are covered by a shell. Mollusks are classified as univalves, bivalves, and cephalopods. Univalves have a single shell. Abalone, sea urchins, and conch are examples of univalves. Clams, oysters, and mussels are examples of bivalves, or mollusks with two shells. Cephalopods, such as octopus and squid, have tentacles that are attached to the head and ink sacs. They move by expelling water through a tubular siphon located under the head.

Buying Shellfish

As with all food, fresh is best for shellfish. Shellfish should have a fresh, mild, sea-breeze odor. In addition to noticing the odor, there are several other things to look for that are specific to each type of shellfish.

Lobsters and crabs should be purchased live and as close to the time of cooking as possible. Both should actively move their claws; lobsters should flap their tails tightly against their chests or, when picked up, curl their tails under their shells. However, if the lobsters and crabs have been refrigerated, they will not be very active. Do not purchase any lobsters or crabs that do not show these signs of life.

Shrimp should feel firm to the touch.

A fresh shrimp should feel firm to the touch.
A fresh shrimp should
feel firm to the touch.
Hard-shell clams, mussels, and oysters, purchased live in their shells, should have tightly closed shells or snap tightly closed when tapped. If they do not close when tapped, they are dead and should be discarded.

Soft-shell clams are unable to close their shells completely. To determine if they are alive, gently touch the protruding neck of each clam to see if it will retract. If the neck does not retract slightly, discard the clam. Discard any clams, mussels, or oysters that have cracked or broken shells.

Freshly shucked clams, sold in their liquor, should be plump, moist, and shiny. The color varies from grayish green to beige to light or dark orange, depending on the variety.

Freshly shucked oysters should be surrounded by a clear, slightly milky, white or light gray liquid. Oysters are usually creamy white but the color varies depending on the variety.

Freshly shucked scallops vary in color from creamy white to tan to a light pink color. Bay scallops, generally found on the East Coast, are about 1/2 inch in diameter. Sea scallops are larger, about 11/2 inches in diameter.

Squid should have cream-colored skin with pinkish patches.

Frozen shellfish should be packaged in a close-fitting, moisture-proof package that is intact at the time of purchase. To learn more about freezing and storing freshly purchased shellfish, check out the next page.

Want more information? Try these:
  • Cooking: Learn the ins and outs of some basic cooking techniques in this helpful article. 
  • How to Cook Fish: There are several different ways to prepare fish, and most of them are quite easy to master. In this article, you'll find tips for many of the methods, including poaching, baking, and pan-frying.
  • Shellfish Recipes: Dive into the many amazing shellfish recipes featured in this article.
  • How to Cook Clams: Clams are a mollusk that are only available in the summertime and are delicious when steamed or eaten raw. Learn all about cooking clams here.