The 3 Types of Shellfish & Their Unusual Friendship with Salmon

Despite the name, shellfish are not a type of fish! They are actually small, boneless creatures that live in their own shell house or shell-like partial exterior, dwelling in seas and oceans.

Scientists call them aquatic invertebrates and recognize three different families of shellfish: molluscs, crustaceans, and echinoderms. Don’t worry, you don’t need to remember the names!

Molluscs are the richest group of shellfish with more than 85,000 living species, including clams, mussels, oysters, winkles, and scallops.

Crustaceans are a group of multi-legged shellfish with skeletons on the outside of their bodies. This family has more than 50,000 different types, among which are shrimp, prawn, lobsters, crayfish, and crabs.

Echinoderms are not quite as common for eating, although you may enjoy them! This species lives mainly on the seafloor in saltwaters. Among them are sea cucumbers and sea urchins.

Shellfish are a popular food all over the world. They are rich in iron, zinc, magnesium, and vitamin B12—all of which have a positive effect on the physical health of the body. For example, only 85 grams / 3 ounces of oysters have almost 100% of the daily value for zinc. Most types of shellfish are eaten steamed, baked, or fried, while some—such as oysters and clam—can be eaten raw or partially cooked.

In addition to being nutritious for humans, shellfish also have a very important role in keeping seas and oceans clean and healthy.

In aquaculture, we have discovered that salmon and shellfish live well together, sharing the same water space. They thrive in a very effective state of symbiosis.

Sea cucumbers and sea urchins usually inhabit the bottom under the salmon cages and eat available leftovers. Scallops and mussels filter the water around the salmon cages through their shells. And seaweed absorbs unnecessary nitrogen and phosphorus.

Check out our coloring page on aquaculture and this helpful illustration by National Geographic.

And one last curious fact: “finfish” is a term used to describe ordinary fish and to differentiate it from the shellfish species!