Fun facts about mollusks

Published 12:31 pm Tuesday, August 29, 2023

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Last week, we learned of the wonders of kelp. This week’s “food from the sea” is shellfish, and as with many culinary items, shellfish can be subdivided into two categories: mollusks and crustaceans. 

These are two distinct groups of invertebrates that belong to the phylum Arthropoda, whose terrestrial family members include insects, millipedes, centipedes, spiders and scorpions. The mollusk family includes clams, scallops, squid, octopus, oysters and mussels. 

The derivation of the word mollusk comes from the French “mollusque,” which itself originates from the Latin “molluscus,” meaning soft. 

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Nearly all shellfish live in saltwater, but the name also refers to species found in freshwater. Most species of mollusks have a soft body, protected by a hard external shell consisting of calcium carbonate, which is the main ingredient in both eggshells and seashells. 

There are many healthful benefits derived from mollusks. Shellfish provide an excellent source of several valuable vitamins and minerals, including vitamin B12, choline, selenium, iron and zinc. These nutrients play a crucial role in energy production, immune system response, blood cell formation and blood vessel health, brain function and proper bone formation. Molluscan shellfish also provide protein with a high biological value. Biological value is a measure of the proportion of digested protein that can be readily used in the process of protein synthesis by cells of an organism. In other words, mollusk protein provides all amino acids, in ratios that can form all the specific proteins the body needs. 

Additionally, shellfish yield omega-3 fatty acids. Omega 3s are healthful fats that have been demonstrated to prevent heart disease and stroke, help control lupus, eczema and rheumatoid arthritis, and play a protective role in cancer and other conditions. Molluscan shellfish are very lean. In fact, most shellfish contain less than 5 percent total fat, especially saturated fats.        

Fun facts: Most mollusks have more than one heart, and have a lifespan ranging from two to 41 years. Creatures like octopuses and squid are considered advanced mollusks., and there are flying squid, which, like flying fish, jump out of the water at speed and glide through the air for a while. 

Colossal squid are the largest invertebrates on earth, with a combined body and tentacle length of up to 46 feet, with a weight of up to 1,000 pounds. Some mollusks have adapted quite a defense mechanism. When some octopus and squid species feel threatened, they release large amounts of ink into the water, so they can escape. 

Think only oysters produce natural pearls? Not so. Gem-quality pearls are harvested from oysters, clams and mussels. The most ancient jewelry ever found was strings of beads that consisted of sea snail shells.        

David Crocker is a nutritionist and master personal trainer. Questions? Email David at or text (864) 494-6215.