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15 Types of Ocean Mollusks

by Stephanie

In the ocean there are so any kind of living beings with different species exist. Starts from the small size living beings until the big size of living beings. And one of the ocean living being is known as and classified as mollusks. Mollusks is known as invertebrate animals. And maybe you only knew that mollusks is being treated as a delicacy by human

. Some of it edible to eat but some species of mollusks also not edible to eat. There are some types of ocean mollusks that can be found beneath the ocean. And maybe there are some mollusks that you never knew before.

The existence of mollusks can be found in the world’s ocean like nearly everywhere. Talking about its species there are about 120,000 different species of mollusks. Because there are so many types of ocean mollusks, I would like to share you with some of the types of it.

1. Abalone

There are so many types of abalone in the ocean. Abalone has another common name such as ear shells, sea ears, and muttonfish.

This species of ocean mollusks is still classified as snail. This mollusks is considered as an edible food where people can actually eat abalone both raw or cooked. Talking about the size of abalone, this animal can actually grow up to 200 mm or equal to 7.9 inches.

2. Clams

Clam is actually classified as a bivalve mollusks. It is called clams because it is edible. There are also some largest clams in the world that you probably don’t know before.

The life cycle of clam itself is actually short because it live for only a year but there are some species that can live longer. Unlike any other mollusks, clam does not live by attach in the substrate.

3. Mussels

Just like clams, mussels is also classified as bivalve mollusks. You may find mussels both in the salt water and fresh water and it feeds on plankton. Since it feeds on plankton the existence of mussels can be found around the rock near the water surface or coastline.

Not only plankton, it also feeds on microscopic organism. Since it is edible, human eat it as delicacy but its predator is not only human but also including seabirds and starfish.

4. Octopus

Another types of ocean mollusks is octopus. This type of mollusks has eight arms that will be trailed behind when it swims.

Even though the size and the habitat of octopus can be found in almost any depth of the ocean but this types of mollusks can be classified as a mollusks that has a short life cycle.

5. Oysters

Oysters can be found in the saltwater and brackish water. It is harvested by human and being served as delicacy both raw and cooked.

There are some oysters that can produce pearls and those oysters are harvested for their pearls. The shapes of oysters itself is irregular compared to another mollusks.

See also: Types of Ocean Habitats – Threats to Marine Habitats


Just like octopus, squid also has eight arms. It is a strong swimmer in the ocean and can “fly” beneath the ocean due to its ability to swim.

Talking about the squid size, most of them is not longer than 60 cm. But there is also a giant squid which is a species of  squid that can reach its length up to 13 m.

7. Scallops 

Scallops is also one of many ocean seashells. Although we know that scallops become one of the delicacy but there are so much more that we need to know about scallops.

We may find scallops in the world’s ocean which means we nearly can find it anywhere but not in the freshwater.

Most of the scallops population can be found in the Indo-Pacific region until 100 m depth.

8. Sea Slugs

Basically sea slugs is a snail that has been through an evolutionary process where it lost its shells.

There are so many variation of size, shape, and color of the true sea slugs which makes it looks even prettier. To consume its food better, sea slugs has a small sharp teeth known as radula.

See also: Water Snails Facts

9. Nautilus

Nautilus is known because of its shells that is smooth which is creating a whorl sections.

Because of its shape that look like a circle, Nautilus movement in the water is helped by the jet propulsion system inside its body. What is amazing about this species of mollusks is that its life span can exceeding 20 years.

See also: List of Marine Invertebrates

10. Chiton

Even though chiton doesn’t look like it has a shell but it actually has. Its shell is made up from eight separate shell valves.

The existence of chiton itself also can be found nearly everywhere starts from the cold water area until tropical area.

Most of the population if you want to find them is living in the rocky area because they inhabit there.

11. Sea Hare

Sea hare or sea hares is named hares because of its rhinopores that is rounded and shaped like a hare. Sea hares shells is so soft since it is made of proteins.

And if another mollusks will have an external shells, this species of mollusks has internal shell. Since it is classified as mollusks, sometimes we are wondering how big the mollusks can grow.

And for sea hares, it can grow up to 75 cm long. What you need to know about sea hares is that even though some species of it looks creepy but it actually feeds on seaweed and they are classified as herbivore.

See also: Herbivores in The Pacific Ocean – Herbivores in the Coral Reef

12. Bubble Shell

Bubble shell is the other types of ocean mollusks. Compared to another mollusks bubble shell has a medium size. Bubble shell is also has a scientific name of Bulla.

And it is classified as a nocturnal animals since its activity will began during the nights. You may find it in the shallow sandy bottom area. And probably near the algae population since it feeds on it.

13. True Limpets

To find true limpets you need to take a look closer into the seagrass because they like to stay or inhabit there. The existence of true limpets almost can be found in all ocean zone.

Starts from the shallow area to the deepest part of the ocean. It feeds on algae that grows in the rock so you may also find it there too. True limpets or limpets in general is consumed by fish, starfish, shore birds, human, and seals.

See also: Importance of Algae in Ocean – Types of Algae

14. Cockles

Cockles is another species of bivalve mollusks that is edible. It lives in all around the world and you can find it easy in the sandy coastlines that has a shelter.

One fun fact about cockles is that its shells can close completely unlike the other species of clams. Throughout the world’s ocean there are about 205 different species of cockles.

15. Cuttlefish

Cuttlefish or known as cuttle is known as a species of fish that is still related to octopus and squid. Even though the name has the word “fish” but cuttlefish is classified as a mollusks. The size of cuttle fish on average can reach the number of 25 cm for its mantle length.

But, the largest species of cuttlefish which is Sepia apama can reach its mantle length up to 50 cm. Talking about its life cycle actually cuttlefish has a short life cycle where they can only live up to 2 years.

So those are the types of ocean mollusks that I can share you with. Hopefully by reading this article you can actually know that there are a rich diversities beneath the ocean that is so beautiful to be preserved.

The diversity may not only include a large species of animal but also a small species of animals like mollusks. Thank you for keep following our website and reading our articles, this means that you are aware towards the deep ocean ecosystems.

We might not can do the huge steps to save the ocean but simple act of caring from us can actually save the ocean environment.

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