American Oceans

What’s The Difference Between Clams and Oysters?

Clams and oysters are two of the most popular shellfish in the world. Although they have some similarities, they are also different in many ways.

an exposed oyuster bed at low tide

Both clams and oysters are bivalves, which means they have two shells that are hinged together. They are also both filter feeders, meaning they extract food particles from the water that surrounds them.

The two have some key differences, though. Read on below to learn all about them, and more!

Differences Between Clams and Oysters

lots of clams in a pile

One of the most noticeable differences between clams and oysters is their size. Clams are generally smaller than oysters, with an average size of about 2-3 inches in length.

Oysters, on the other hand, can grow to be much larger, with some species growing up to 12 inches in length.

This size difference can also be seen in their shells, with oyster shells being thicker and more irregularly shaped than clam shells.


In addition to their size, clams and oysters also have different appearances. Clams typically have a more elongated shape, with a slightly curved shell that is symmetrical in appearance.

Oysters, on the other hand, have a more irregularly shaped shell that is often rough and bumpy in texture.

Oyster shells can also be more colorful, with shades of blue, green, and purple, while clam shells are usually a more uniform brown or gray color.

Texture and Taste

While clams and oysters may look different, they also have distinct differences in texture and taste.

Clams are known for their tender, chewy texture and a mild, slightly salty flavor. Oysters, on the other hand, have a firmer, meatier texture and a briny, almost metallic taste.

Some people describe oysters as having a creamy texture, while others find them to be slimy or gritty.

Similarities Between Clams and Oysters

a pile of live oysters

Clams and oysters are both bivalve mollusks that can be found in both freshwater and saltwater habitats.

They are filter feeders that live in the sediment at the bottom of bodies of water.

Clams and oysters are often found in intertidal zones, where they are exposed to air during low tide and submerged in water during high tide.


Both clams and oysters have two shells that are connected by a hinge. The shells are made of calcium carbonate and are used for protection.

The shape and size of the shells vary depending on the species and habitat.

Clams and oysters can also produce pearls, which are formed when a foreign object becomes trapped inside the shell.


Clams and oysters belong to the same phylum, Mollusca, and the same class, Bivalvia. There are many different species of clams and oysters, each with its own unique characteristics.

Some of the most common species of clams include quahogs, littlenecks, and razor clams, while some of the most common species of oysters include Pacific oysters, Eastern oysters, and Olympia oysters.

Bivalve Mollusks

As bivalve mollusks, clams and oysters share many similarities in their anatomy and physiology.

Both have a muscular foot that is used for movement and digging in the sediment. They also have a siphon that is used for filter feeding, and a mantle that secretes the shell.

Types of Oysters and Clams

different types of clams at the seafood market

Oysters are a popular type of edible mollusk that come in various types and sizes. Some of the most common types of oysters include the Eastern oyster, European flat oyster, Atlantic oyster, and Olympia oyster.

Each type has its own unique appearance, flavor, and texture.

The Eastern oyster is the most common type of oyster found in North America. It has a hinged shell and a shiny appearance.

The European flat oyster, on the other hand, has a flatter and more elongated shell. It is typically saltier and has a more pronounced flavor than other types of oysters.

The Atlantic oyster is another popular type of oyster that is known for its sweet and buttery flavor.

It is typically smaller in size than the Eastern oyster and has a slightly chewy texture. The Olympia oyster is the smallest type of oyster and is known for its briny flavor and chewy texture.

Types of Clams

Clams are another type of edible mollusk that come in various types and sizes. Some of the most common types of clams include razor clams, Atlantic surf clams, and littleneck clams. Each type has its own unique appearance, flavor, and texture.

Razor clams are long and narrow with a gray appearance. They are typically sweeter and more tender than other types of clams.

Atlantic surf clams, on the other hand, have a more chewy texture and a slightly briny flavor.

Littleneck clams are the smallest type of clam and are known for their hinged shell and sweet flavor. They are typically served raw on the half shell and are a popular ingredient in clam chowder.

Harvesting and Threats to Clams and Oysters

a person harvesting oysters on cape cod

Both clams and oysters are harvested from the ocean floor, but the methods used to harvest them differ.

Clams are often harvested by hand or with small rakes, while oysters are usually harvested with tongs or dredges.

In some areas, oysters are also grown on artificial reefs, which can provide a more sustainable source of oysters.

Harvesting clams and oysters can have an impact on the surrounding ecosystems. For example, dredging for oysters can damage oyster reefs and other habitats, while hand harvesting can disturb the ocean floor and harm other marine life.


Both clams and oysters face threats from pollution and overfishing. Pollution can make them unsafe for human consumption, while overfishing can deplete populations and damage ecosystems.

In addition, both clams and oysters can be sources of foodborne illness if they are not handled and cooked properly.

Restaurants and other food service establishments must take care to ensure that the clams and oysters they serve are safe for consumption.

Frequently Asked Questions

What are the similarities between clams and oysters?

Clams and oysters are both bivalve mollusks that live in saltwater and are often harvested for food. They both have two shells that protect their soft bodies, and they both filter water to feed. Additionally, both clams and oysters are low in fat and high in protein.

Do oysters and clams taste the same?

Although both clams and oysters have a briny taste, they do not taste the same. Clams have a slightly sweeter taste and a chewy texture, while oysters have a more delicate, buttery taste and a softer texture.

What is the difference between opening oysters and clams?

Opening oysters and clams requires different techniques. Oysters have a rounder, flatter shell, and are typically opened with an oyster knife by prying the shell open at the hinge. Clams, on the other hand, have a more elongated shell, and are often opened with a clam knife by inserting the blade into the shell and twisting it to separate the two halves.

What are some facts about clams and oysters?

Clams and oysters are both filter feeders, which means they filter water to extract food. Oysters can filter up to 50 gallons of water per day, while clams can filter up to 10 gallons. Additionally, both clams and oysters are known for their ability to produce pearls, although pearls from oysters are more valuable.

How do clams and oysters differ in terms of nutrition?

Clams and oysters have similar nutritional profiles, but there are some differences. Clams are slightly higher in calories and fat than oysters, but they also contain more iron and vitamin B12. Oysters are higher in zinc and vitamin D.

What are the differences between the pearls found in clams and oysters?

The pearls found in clams and oysters differ in size, shape, and value. Clam pearls are typically smaller and more irregular in shape, while oyster pearls are larger and rounder. Oyster pearls are also generally more valuable and sought after for use in jewelry.

Add comment