Sealife guideBivalves: shellfish wonders of the oceanThe marine mollusks

Last updated on 09/02/2025 at 12:22 AM

The class of bivalves is characterized by a shell composed of two parts, called valves, which are hinged and more or less symmetrical.

The noble pen shell is a type of bivalve

The most well-known bivalves include oysters, mussels, scallops and clams.

Bivalves have a calcium carbonate shell equipped with strong muscles that can close the two valves tightly in response to external threats.

Bivalves feed by filtering water through their gills. The water current is generated by the action of tiny cilia.

Discover marine bivalves

Giant rock scallop
(Crassadoma gigantea)

Great atlantic scallop
(Pecten maximus)

Noble pen shell
(Pinna nobilis)

Spiny pink scallop
(Chlamys hastata)

Discover marine mollusks

Dotted sea slug
(Peltodoris atromaculata)

Indian nudibranch
(Caloria indica)

Ocellated sea slug
(Plakobranchus ocellatus)

Pharaoh cuttlefish
(Sepia pharaonis)

Red-lined flabellina
(Coryphellina rubrolineata)

Umbilical egg shell
(Calpurnus verrucosus)

Yellow speckled doris
(Hypselodoris godeffroyana)

Zigzag cowry
(Palmadusta ziczac)

Our latestUpdates

Monday, March 2nd 2026

The blueface angelfish

The blueface angelfish is a very colorful fish of the tropical coral reefs of the Indo-Pacific, recognizable by its bright blue head and its bluish body finely reticulated with yellow.

Wednesday, February 18th 2026

The Atlantic tarpon

The Atlantic tarpon is a large coastal fish that can grow up to 8 feet long and weigh over 330 pounds, with a silvery body covered in large, reflective scales. Known as the Silver King, it is famous for its spectacular leaps and fierce fight when hooked by sport fishermen.

Friday, January 30th 2026

The dugong

Discover the dugong, a gentle “sea cow” of tropical waters. Learn about its habitat, diet, reproduction, morphology, and the threats facing this unique marine mammal.

Photo of the Day

Murène tigre
(Enchelycore anatina)