Along the world's miles of coastline, man has always had a readily available food source - high in protein and trace minerals, because of the many kinds of molluscs to be found there. Mussel and oyster beds, clam-flats and other abundant shellfish have always provided an easy source of food.

Today, fisheries in Europe, Japan and the US alone produce over 1 billion pounds of oyster meat each year. Abalone, a great delicacy, can fetch up to three hundred dollars per pound. Could you imagine a world without Clam Chowder? 

*One problem does exist; however. At certain times of the year, (usually the warmer months) many species of marine molluscs become very poisonous due to an algal bloom known as "red tide" The molluscs filter feed on these tiny animal-like plants (called "dinoflagellates" which produce toxins. Eating shellfish during "Red Tide' can cause serious illness and even death to humans. This could be one explanation why in the Jewish and Muslim cultures, shellfish are considered unclean and forbidden.
(Note: Algae are a diverse group of organisms including many which are one-celled and can swim like animals, and all the many kinds of seaweed.)

Tastes in molluscan food vary tremendously from one person to the next and from culture to culture; however, when it comes to a question of survival, most molluscs are edible. Some are considered delicacies such as oysters and escargot, while others such as the clams and mussels of fresh water ponds and streams are less likely to be consumed due to taste - but none-the-less are very edible!  Terrestrial molluscs are also eaten. France alone consumes 5 million pounds of escargot (a large tree-snail, Helix aspersa Moller)
every year.

Here are some more examples of molluscs commonly eaten:

clams (Family Myidae and Veneridae) - particularly honored in the New England States of the USA!! Veneridae includes the Quahogs (Mercenaria sp.) that are also to be found up and down the eastern U.S coastline.

Protothaca staminea Little neck Clam

Argopecten gibbus Atlantic Calico Scallop

scallops (Family Pectinidae): There are many different kinds ("species") of scallops eaten in many parts of the world.(Note: The "scallops" you purchase in the supermarket are in fact the muscle which the animal uses to close the two halves of its shell tightly together - called the "adductor" muscle.)

oysters (Family Ostreidae): When eaten raw (something I personally can't imagine doing, but many do!), are often thought to be an aphrodisiac.  Oysters can get expensive, which is probably why there is a recipe known as Oysters Rockerfeller!"

Crassostrea virginica Atlantic or Eastern oyster

Perna viridis Green mussel Mytilus edulis common blue mussel

mussels (Family Mytilidae):  (Note: These are especially prone to poison people with "Paralytic Shellfish Poisoning", which is caused by a tiny, one-celled animal called a dinoflagellate which infects mussels and other bivalves from time to time.  During these times, they produce a strong neuro-toxin (i.e., it affects the nervous system) called "demoic acid", which has killed many and made millions of people sick: NEVER eat mussels or any other bivalve when you don't know if the area has a problem with this deadly kind of food poisoning!!!  In a long-term survival situation, you could perhaps eat a very small nibble, then wait a day or two to see if you get ill , before going "whole quahog" (a little in-joke - it is a New England and Atlantic Canadian clam - pronounced "cohog"!) over them.

whelks (Family Buccinidae:- VERY big in Japan, and the French pickle them for winter eating!

Buccinum undatum Common Northern Whelk

Cerastoderma edule Common edible cockle

cockles (Family Cardiidae): (Europe & Malaysia) - as in Mary Molone, who cried "Cockles and mussels, alive, alive-o!" (shellfish are one of the few kinds of food that are kept alive right up to the moment of cooking: this is because they go bad very quickly, once dead!)

conchs (Family Strombidae): produce a large amount of meat, and are especially treasured in the Caribbean region, where the giant Pink (or Queen) Conch (Strombus gigas Linne) is farmed extensively. Strombus gigas in the Bahamas is heavily exploited for food, and along with two species of Cassis (Helmet shells), are often cultivated in Aquaculture farms.

Stombus gigas Giant Pink or Queen Conch

Loligo spp, Illex illecebrosus California or Market squid

squid & octopus: Particularly popular in Japan (where squid are called "Calamari"), but they are catching on in parts of the Western World.  In Newfoundland (Canada), they are used by the ton as bait for several kinds of fish. (Note:  These are cephalopods - a totally different Class of molluscs from the gastropods or bivalves.  They are the most developed molluscs, and some are regarded as the most intelligent invertebrates (animals without a backbone) in the world!) For more information on the cephalopods, see An Advanced Introduction to the Molluscs for details on the taxonomy of the Mollusca phylum)

pen shells (Family Pinnidae): Japan and the Mediterranean and occasionally in the USA). They reportedly taste similar to scallops.

Pinna nobilis Pen or Fan Shell

Bathybembix bairdii Baird's topsnail

top Shells (Family Trochidae: Caribbean especially, where the West Indian Top Shell (Cittarium pica Linne, 1758). is considered a delicacy by some of the locals.

abalone (Haliotis spp): a well-known Tasty Morsel in many parts of the world.  Some rare species can sell for up to $300 a pound ($760 per Kilo)!

Haliotis corrugata Pink Abalone

Littorina angulifera Angulate or Mangrove Periwinkle

periwinkles (Family Littorinidae): These, once again, are much loved by the French, who like their seafood, even when it is very small!

coquinas (Donax spp)(Caribbean): - Tiny clams, for chowder!

Donax variabilis Southern or variable coquina

Cellana exarata Hawaiian Opihi

limpets (Families Patellidae, Fissurellidae, and Acmaeidae:  Example: "Opihi" (Cellana exarata (Reeve)) lives on the rocks in Hawaii.

Chitons (Class Polyplacophora): several families used for food). Example: Pacific Northwest Native Americans ate the Giant Pacific Chiton (Cryptochiton stellari (Middendorf)), which gets up to 300mm (12") long!

Cryptochiton stelleri Giant gumboot chiton

Turbo cornutus Spiny top shell

turban shells  (Family Turbinidae:( Entire Indo-Pacific, but especially Japan, where, most of the time, if it comes from the sea, they will eat it!)

helmet shells (Family Cassidae: These can grow very large indeed: a 300 - 350mm (12-14") Horned helmet (Cassis cornuta Linne, 1758) could feed a whole family!

Cassis madagascariensis King conch or Emperor Helmet

Tridacna gigas Giant clam

giant clams (Family Tridacnidae: Although they are rare and protected today, just imagine the amount of meat a fat, 1300mm (nearly 4 feet!) Giant Clam (Tridacna gigas (Linne)) could produce!  The Bear Paw clam (Hippopus hippopus Linne) is still popular today in kitchens in the Philippines.

Busycon carica: is an important ingredient in the Italian dish of "scungilli marinara", and is commonly referred to as the Bulot shell.

Busycon carica Knobbed Whelk

Only a few molluscs are actually poisonous. A wide variety of molluscs end up in cooking pots around the world every day.- Most of the animals that once created and lived in most ornamental shells sold in stores probably ended up that way!