Shellfish are a fascinating topic for anyone interested in learning English vocabulary related to sea creatures. They come in many shapes and sizes, from clams and mussels to shrimp and crabs. Understanding the different types of shellfish and their uses can expand your vocabulary and enhance your language skills.
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List of Shellfish
Shellfish come in a multitude of shapes and sizes, varying from the familiar to the utterly alien. Some have pincers that can break bones, others have eyes that can see wavelengths of light well beyond the range of the human visible spectrum, and some have claws that can punch so hard it boils the water around them. Others are regularly eaten as a delicacy, and others are deadly poisonous. But all of them are interesting. Here’s a list of some of our favorites:
- Brown Crab
- American Lobster
- Mantis Shrimp
- Butter Clam
- Sea Urchin
- Whelk
- Scallop
- Oyster
- Mussel
- Abalone
- Crawfish
- Cockle
- Prawn
What Are Shellfish?
The term “shellfish” is commonly used to describe a wide range of aquatic animals that inhabit both saltwater and freshwater environments and have a hard outer shell, often made of a material called chitin. However, definitions can vary depending on context.
For example, many food regulatory authorities narrowly define shellfish as mollusks (animals like clams and limpets) that filter their food from their environment. Notably, this does not include animals like crabs or lobsters, sometimes called ‘Crustaceans‘, yet many of us would call them shellfish in common speech.
The reason for this confusion is that the word “shellfish” is not used in scientific classification systems, which are collectively known as taxonomy. This is because life underwater is dangerous, and many unrelated branches of the tree of life have independently developed hard outer shells as protection. As a result, no single taxonomic group can claim the name shellfish. This process is known as convergent evolution, in which unrelated species develop similar characteristics because those traits are highly useful in their environment.
For example, both the sea turtle and the mantis shrimp benefit from having a hard shell, yet it is difficult to place them within the same biological group. In fact, many people would not classify the sea turtle as a shellfish at all.
Shellfish List with Facts and Pictures
The Brown Crab (Cancer Pagurus)
Also known as the edible crab, the brown crab is perhaps one of the most familiar shellfish species. Found in the North Atlantic, the North Sea, and sometimes in the Mediterranean, the brown crab has become the image many people most strongly associate with the word “crab.”
With over 60,000 metric tonnes caught annually, the brown crab is the most fished crab in Western Europe.
The American Lobster (Homarus americanus)
Another widely eaten shellfish is the American lobster, most commonly found in the colder northern waters of the eastern seaboard and the seas surrounding the coastal regions of eastern Canada. Commonly weighing up to 9 lbs (4 kg), the American lobster is considered a delicacy across the continent and is often served as an expensive luxury dish.
However, this was not always the case. In the early days of European settlement in North America, lobsters were so abundant that they were farmed and mulched to make fertilizer for crops. In desperate times, they were even eaten by the poor in regions where they were heavily fished.
Mantis Shrimp
Mantis shrimp are a group of shrimp-like species found in the temperate regions of the Indian and Pacific Oceans. One of the few shellfish that actively hunt their prey, mantis shrimp are equipped with extremely powerful front claws and remarkable eyes.
The mantis shrimp’s claws can strike at tremendous speeds—up to 51 mph—to attack prey or deter predators. This strike is so fast that it creates a cavitation bubble, which collapses and produces a powerful shockwave capable of stunning or killing prey on its own.
A mantis shrimp’s claws can take the form of either hard clubs or sharp spears. Mantis shrimp kept in captivity have been known to smash aquarium glass and seriously injure human hands when handled carelessly.
The mantis shrimp’s eyes are equally remarkable. They are compound eyes, similar to those of flies, and are mounted on separate eye stalks. Each eye is divided into three sections, giving the animal trinocular vision on each stalk and extremely precise depth perception. In addition, mantis shrimp can see deep into the ultraviolet spectrum and detect polarized light. All this allows them to use their claws with deadly accuracy.
The Butter Clam (Saxidomus gigantea)
The butter clam is a large species of saltwater clam found along the western coast of North America, from the Bering Strait as far south as San Francisco Bay. They can be eaten raw or steamed, like many other clams; however, the butter clam has a deadly secret.
Butter clams can contain neurotoxins known as saxitoxins, which cause paralytic shellfish poisoning. As their name and classification suggest, these toxins interfere with nerve function, preventing nerve cells from transmitting signals properly through the nervous system. This can lead to serious medical conditions, most notably paralysis, and in severe cases, heart failure.
To make matters worse, the concentration of saxitoxins in butter clams increases during the summer months due to algae blooms caused by increased sunlight. As delicious as they may be, would you risk it?
