11 Types of Oysters: Species, Facts and Photos

There are various types of oysters, from those found in coastal marshes to those hidden in coral reefs. Biologists, ecologists, and gourmets alike have marveled at the diversity of these mollusks. 

Despite their simple exterior, oysters have unique characteristics and behaviors that warrant study. Let us uncover the hidden mysteries behind these shelled critters!

General Information about Oysters

Oysters enjoy tremendous value for their ecological and gastronomic importance. For instance, you may be familiar with West Coast and East Coast Oysters served in restaurants that are served raw on a half shell or in a stew. 

East Coast oysters tend to have a silky and meaty texture compared to the creamier texture of West Coast oysters. Humans also farm oysters for consumption and sale. In the US, five species of oysters are harvested yearly.

These creatures also come in different sizes and inhabit brackish waters and marine environments. 

Moreover, oysters form dense groups known as oyster reefs in tidal flats, estuaries, and bays. These reefs provide habitats for various marine species, enhancing the biodiversity of their ecosystems.

Related Read: Oyster Facts.

Oyster Taxonomic Classification

Oysters are a mollusk type belonging to the Class Bivalvia, Order Ostreoida. There are two families in this order: Ostreidae and Pteriidae. 

Ostreidae is home to the edible 'true oysters,’ with multiple genera, like Crassostrea and Ostrea. This oyster type can switch sexes, adapt to their environment, and employ filter feeding.

Moreover, their calcified shells protect them from predators and the elements. Seafood lovers also enjoy their diverse flavors, which depend on their habitat and diet.

Pteriidae comprises pearl oysters, with only one genus, Pinctada. They live in the warm waters of the Indo-Pacific region and have a smooth, round exterior and an iridescent lining known as the nacre or mother-of-pearl. 

Unlike the true oysters, pearl oysters produce pearls. Pearl formation results from a biological process where a tiny irritant gets trapped inside the oyster and covered in nacre layers. As more and more research develops techniques, the market for the cultivation of pearls exceeds the demand for natural pearls¹.

Moreover, pearl oysters have tough flesh, and people do not typically consume them.

11 Types of Oyster Species

Quick links to the different types of oysters:

1. Pacific Oyster (Crassostrea gigas)

Pacific Oysters, also called Japanese oysters or Miyagi oysters, originate from the Pacific coast of Asia. It is the most cultivated oyster globally due to its sweet, mild flavor and creamy texture. It is also known for its adaptability to different environmental conditions, which makes it a favorite among oyster farmers².

The Pacific Oyster grows fast and can change gender at different stages of its life, which helps boost its population on farms. However, overharvesting and diseases threaten Pacific Oysters.

2. Kumamoto Oyster (Crassostrea sikamea)

The Kumamoto oyster is a small but popular variety. Biologists have debated whether it should be classified as Crassostrea sikamea or a subspecies of Crassostrea gigas. 

It has a sweet and mild flavor, buttery texture, and melon-like aftertaste. Moreover, its prime season runs from fall to spring. It spawns in warmer waters than other oysters.

Kumamoto Oysters feed on phytoplankton and tiny marine algae. They take up to three years to reach market size and resist common oyster diseases.

3. Atlantic Oyster (Crassostrea virginica)

The Atlantic Oyster–also known as Eastern Oyster–is commonly found in estuaries and intertidal zones along North America's eastern seaboard and Gulf of Mexico coast. They help build extensive oyster reefs that provide homes for various marine species. 

Moreover, Eastern Oysters help keep marine environments healthy by feeding on algae, plankton, and other tiny particles suspended in the water. They are also hermaphroditic–they can change their sex during their lifespan. 

Atlantic Oysters are famous in oyster bars and seafood restaurants due to their rich, salty flavor and firm texture.

4. Olympia Oyster (Ostrea lurida)

The Olympia Oyster is the only oyster native to the Pacific Northwest coast, from Alaska to Baja California, with a distinct coppery taste and sweet metallic finish. It is a rare treat because commercial farms rarely grow them. 

Olympia Oysters are critical water filters, cleaning up to 25 gallons of water per day. Unfortunately, overharvesting, pollution, and invasive species have led to a decline in their population. Conservationists are working hard to restore their numbers.

5. European Flat Oyster (Ostrea edulis)

The European Flat Oyster is native to Europe's waters and known for its distinct shell and delicate flavor profile. These oysters are also known as Belon Oysters. It is a hermaphrodite and feeds on phytoplankton and other particles in the water. 

Humans commercially cultivate European Flat Oysters despite their slow growth compared to other oyster varieties, but overfishing and diseases threaten their populations. The oyster plays an essential role in the ecosystem by providing a habitat for marine life and aiding in water filtration.

6. Sydney Rock Oyster (Saccostrea glomerata)

Sydney Rock Oysters, found in Australia and New Zealand, thrive in brackish waters. They have a sweet and mineral-rich flavor, drawing seafood lovers from all over. They are essential to Australia's aquaculture industry.

7. New Zealand Rock Oyster (Crassostrea gigas)

The New Zealand Rock Oysters were introduced to New Zealand in the 1970s.They are now a prominent part of the country's marine life and aquaculture. 

These types of oysters can live in intertidal and subtidal zones and adapt to various temperatures. Moreover, they have rough and irregular shells that provide homes to other marine creatures. 

The oysters have a sweet and salty taste with mineral undertones. However, disease and overfishing threaten their survival, making sustainable farming practices necessary.

8. Portuguese Oyster (Crassostrea angulata)

The Portuguese Oyster is an oyster species typically found along the coasts of Europe and North Africa. It is well-known in the seafood industry and popular in Portugal due to its unique flavor. 

The oyster’s taste reflects its habitat, intertidal and subtidal zones, where it thrives in muddy or sandy substrates. 

These filter feeders consume plankton and other tiny sea life, keeping their ecosystem clean and balanced. 

9. Pinctada Oyster (Pinctada margaritifera)

The Pinctada oyster is a bivalve mollusk commonly found in the tropical coral reefs of the Indo-Pacific region. These filter feeders grow to an impressive size by consuming plankton and other microscopic organisms. 

Notably, these oysters produce Tahitian pearls, a precious gem in the global pearl industry. Apart from their beauty and pearl production, Pinctada oysters are a delicacy in certain cultures.

Moreover, people repurpose their shells to create mother-of-pearl items like buttons and inlays.

10. Akoya Oyster (Pinctada fucata)

The Akoya oyster lives mainly in the Pacific Ocean on the coasts of Japan, China, and Vietnam. These small oysters produce beautiful pearls. Unlike larger oysters, they do not serve a culinary purpose. 

Creating Akoya pearls begins with inserting a tiny nucleus into the oyster, which gradually coats it with layers of nacre. The result is a beautiful, iridescent pearl. 

Akoya pearls come in whites, creams, silvers, and pinks. However, their blue pearls are always in high demand. These pearls are of the highest quality worldwide.

11. Pearl Oyster (Pinctada maxima)

Pearl Oysters are famous for producing large pearls. They live in tropical seas, ranging from the Bay of Bengal to the Solomon Islands, in the Indian and Pacific Oceans. Moreover, they live in Australia, Indonesia, and the Philippines, where they attach themselves to coral reefs. 

They have thick and robust shells, providing adequate protection against predators. Moreover, their thick and radiant nacre creates their pearls' unique silver or gold hue. This nacre also comes from oyster’s mother-of-pearl. 

Finally, genetic and environmental factors such as water temperature, salinity, and diet determine their pearls' quality, size, and color.