Shellfish

Shellfish is a broad culinary and fisheries term for aquatic invertebrates with shells or shell-like coverings, especially molluscs and crustaceans.

Shellfish is a broad culinary and fisheries term for aquatic invertebrates with shells or shell-like coverings, especially molluscs and crustaceans. It is used most often for edible species such as clams, oysters, mussels, scallops, shrimp, crabs, and lobsters, and sometimes also includes echinoderms like sea urchins and sea cucumbers. Shellfish are important to Canada’s seafood industry and coastal diets, especially along the Atlantic and Pacific coasts, and Canadian food labelling and allergy guidance treat shellfish as a significant allergen category.

Definition and usage

Shellfish is a broad term rather than a scientific classification. It usually refers to edible aquatic invertebrates with shells, including molluscs and crustaceans, and sometimes echinoderms. The term is not a single scientific group; it is a common name used in food, fisheries, and everyday speech.

Major groups

Common shellfish are divided into bivalve molluscs, gastropod molluscs, crustaceans, and, in some usages, echinoderms. Examples include oysters, clams, shrimp, crabs, sea urchins, and sea cucumbers. Commercial shellfish include bivalves such as oysters, mussels, clams, and scallops, and crustacean shellfish commonly eaten include shrimp, prawns, crabs, and lobsters.

Food and fisheries

Shellfish are an important part of global seafood production and trade. Bivalves are among the most commercially important, and many species are harvested from wild fisheries or aquaculture. Some authorities use a narrower regulatory definition that focuses on molluscs, especially filter-feeding bivalves.

Allergy and regulation

Shellfish is a major food-allergy category, which makes the term important in labelling and public health. Regulatory usage may be narrower than everyday usage and sometimes excludes crustaceans. Shellfish are among the most common food allergens.