Fish and Shellfish

Fish Fish is a classification for aquatic animals that have fins for moving through water, gills for breathing, and an internal bone structure with a backbone (or vertebrae). Fish are classified by their external shape and bone structure as well as by habitat (freshwater or saltwater).

Composition and Bone Structure Fish have a naturally tender flesh consisting of protein, carbohydrates, fat, water, and trace amounts of vitamins and minerals. A significant difference between fish and meat is that fish does not have connective tissue. Because fish has no connective tissue it highly fragile and comes apart easily. Fish are different from one another both externally and internally and are therefore classified as either round, flat, or boneless based on external shape and internal bone structure.

Round Fish Are fish with a long, cylindrical body and an eye located on each side of the head. A backbone runs from head to tail along the upper length of the body, just below the dorsal fin. The is the most common shape for fish. Found in both freshwater and saltwater. Large round fish have inedible scales and are removed prior to preparation.

Types of Round Fish Trout Perch Pike Smelt Tilapia Catfish Salmon Tuna Cod Bass Red Snapper Orange Roughy

Flatfish Thin, wide fish with both eyes located on one side of the head. A backbone runs from head to tail down the center of the body, rather than at the top edge as in round fish. Flatfish swim with the body horizontal, parallel to the surface of the water, with one side facing down and the other side having both eyes facing toward the surface.

Flatfish Cont. The skin on the top is usually dark and may change colors to blend in with its environment, the bottom is usually light in color. Flatfish lay hidden on the ocean floor, with the colorless side down to catch food and avoid prey. The are called either left-handed or right-handed depending on what side of the body their eyes are.

Types of Flatfish Flounder Sole Halibut Skate (Ray)

Boneless Fish Are shaped like round fish; however, they have thick cartilage skeletons instead of bones. Boneless fish often have smooth, tough outer skin without scales. Examples are: Shark Sturgeon Monkfish Swordfish

Lean Fish and Fat Fish Fish are categorized as lean or fat (oily) fish, based on the amount of fat contained in the flesh. Lean fish contain as little as 0.5% fat. Walleye is an example of lean fish. Fat fish contain up to 20% fat and are rich in omega-3 fatty acids and vitamins A and D. Examples include orange roughy, tuna, and salmon. Fat content can affect both taste and cooking methods required. Lean fish are often best prepared using moist-heat methods, while fat fish can be prepared using dry-heat methods.

Fat Content of Common Fish Bluefish 4g Codfish 1g Croaker 3g Sole 1g Flounder 1g Perch 1g Hake 0 Halibut 2g Pike 1g Red Snapper 1g Sea Bass 2g Brook Trout 6g Butterfish 7g Catfish 6g Lake Trout 6g Pompano 8g Rainbow Trout 5g Salmon 9g Shad 12g Mackerel 5g Whitefish 5g

Freshwater Fish Most common types of fish found in restaurants. Some are so popular they are being aquafarmed. Aquafarming is the raising of fish or other seafood in a controlled environment. “Farm-Raised” this is a label you might see at the store if it has been aquafarmed.

Saltwater Fish There are multitudes of saltwater fish on menus, some more popular than others. They may be round, flat, or boneless. Some round fish begin their lives in freshwater but spend most of their time in saltwater, returning to fresh water to spawn.

Market Forms of Fish Each form has certain advantages and disadvantages in terms of cost, convenience, and labor. There are 6 types of market forms of fish. Whole – nothing has been done to the fish. Drawn – only the viscera is removed, with the scales still on. Dressed – a fish that has had the viscera, scales, fins, and gills removed.

Market Forms of Fish Cont. Steaks – is a cross-sectional slice of a larger-size dressed fish. Examples are tuna, salmon, and shark. Fillet – is the fleshy side of a fish. Round fish have 2 and flatfish have 4. Butterfly Fillets – two single fillets from a dressed fish that are held together by the uncut back or belly of the fish.

Shellfish Is a classification for aquatic invertebrates that may have a hard external skeleton or shell. Meaning that they do not have an internal skeleton. Shellfish are commonly categorized as mollusks or crustaceans.

Crustaceans A shellfish that has a segmented, hard external shell. The external shell functions as a skeleton and is called an exoskeleton. Crustaceans are found both in fresh and saltwater. They can breathe underwater, and unlike fish, can survive on land for a few days but need to be kept moist. Examples include lobster, shrimp, crabs and crayfish.

Shrimp and Prawns White tender meat. Both are found in fresh and saltwater. Prawns are more commonly identified with freshwater and shrimp with saltwater. The terms are used interchangeably. In the US and Asia the term prawn is used for larger shrimp. In other parts of the world they are almost always referred to as prawns. The four most common types sold are white (most common), brown (Brazilian), pink (coral), and black tiger shrimp (largest).

Lobster Tail contains a sweet tasting white meat. The colors of lobsters range from brown to bluish-black. All lobsters turn red when cooked. The whole lobster is edible except for the stomach located by the eye. Most often lobster is prepared by poaching, boiling, or steaming. The four main types of lobster are Maine (most common), Spiny (small claws, only the tail is eaten), Slipper (no claws), and Langoustines (similar to shrimp, only the tail is eaten).

Crabs Have tender, sweet tasting meat. Edible crabs can be distinguished from inedible crabs based on the # of legs they have. Edible have 5 pairs and inedible have 4 pairs. Crabs are available fresh (live), frozen, or in canned products. There are 5 varieties taken from the North American Costal waters.

5 Types of Crab Blue – found off the Atlantic Coast. Typically used as soft-shell crab. Usually used fresh within 6 hours of the molting period. Molting is the process by which a crab will shed its hard shell to grow a larger shell. Marketed live, precooked, or frozen. Dungeness – Pacific Crab. Most commonly used as frozen or canned. Meat comes from the body rather than the leg Snow – Also called the spider crab. Similar to king crab but smaller and less expensive. Sold as cooked, or as frozen leg clusters.

5 Types of Crab Cont. King – Largest variety. Weigh between 6 and 20 pounds. Usually sold as cooked or frozen. They are not usually available live as the legs are removed at sea and flash-frozen to preserve quality. Stone – Atlantic crab. Only the claws are harvested. Stone crabs that are caught have one claw removed and are then placed back into the water. In 12 to 16 months they generate a new one larger than before. They are usually served cold.

Crayfish Also known as crawfish or crawdad. Freshwater crustacean that resemble a small lobster. Range from 3” to 7” long. About 98% of crayfish are from aquafarming in Louisiana and the Pacific Northwest. Most commonly used in Creole, Cajun, and French cuisine. Only the tail has edible meat.

Mollusks Is a shellfish with a soft unsegmented body. Some mollusks, such as clams and oysters, have a hard external shell to protect the soft inner body. Other mollusks have a thin internal shell called a cuttlebone. Mollusks can be divided into three classifications: univalves, bivalves, and cephalopods.

Univalves Is a mollusk that has a single solid shell and a single foot. The foot is used to move along the surface of underwater structures. They include adalone and conch. Adalone – Bowl-Shaped shell with a brown exterior. Has a sweet slightly salty flesh and is similar to a clam. Conch – Has a pinkish-orange tail and resembles a large snail. Found in the Caribbean and Florida keys. It has a rubbery flesh and a sweet flavor similar to that of a clam.

Bivalves Have a top and bottom shell connected by a central hinge, which the animal can close for protection. A live bivalve should close when gently tapped. Those that do not or are heavier than normal are dead. The most common types are clams, mussels, oysters, and scallops.

Cephalopods A mollusk with arms that extend from the base of a distinct head. They do not have an outer shell; however, squid and cuttlefish have an internal flat shell referred to as a cuttlebone. Derived from the Greek word meaning from head-foot. They have distinct heads, well-developed eyes, and a mouth that is surrounded by a sharp beak used for cracking shells of shrimp, crab, loster, and other prey. The most common types are squid, octopus, and cuttlefish.