An Easy Guide to Shellfish
The term shellfish denotes two primary groups: molluscs and crustaceans. The primary way of identification is by the external shell. These animals don’t have backbones, only shells. However, it can get a little complicated. Some molluscs, for example, squids and cuttlefish, have shells inside their bodies.
Molluscs have a soft fleshy body and either one shell or a pair of shells. This is where identification of molluscs splits down into two. Molluscs with one shell are known as Gastropods. The shell is coiled and carried on the back. Examples of Gastropods include whelks and winkles. Molluscs that have a pair of shells are called Bivalves. The shells are hinged together and closed by internal muscles. Examples of bivalves include oysters and scallops.
Crustaceans are the other type of shellfish. The body of a crustacean can be divided into 3 separate parts: head, thorax, and abdomen. A crustacean is made up of these segments, and the legs are also jointed. Many crustaceans can be called decapods, as most have 10 legs. The first pair of legs is generally larger than the others as they’re the claws. All decapods’ have their head and thoraxes covered by the carapace. A lobster has a large carapace stretching across the abdomen and head, and a crab has the large carapace across its body.
All shellfish will generally look the same, and if not, it probably is in a bad condition. Always check your seafood before cooking for the best flavour and ensure it’s in a good condition.