Frequently asked questions about oysters


Oysters, male or female?

There is no way of telling male oysters from females by examining their shells. While oysters have separate sexes, they may change sex one or more times during their life span. The gonads, organs responsible for producing both eggs and sperm, surround the digestive organs and are made up of sex cells, branching tubules and connective tissue.

How do oysters breathe?

Oysters breathe much like fish, using both gills and mantle. The mantle is lined with many small, thin-walled blood vessels which extract oxygen from the water and expel carbon dioxide. A small, three-chambered heart, lying under the abductor muscle, pumps colorless blood, with its supply of oxygen, to all parts of the body. At the same time a pair of kidneys located on the underside of the muscle purify the blood of any waste products it has collected.

What is that crab sometimes seen in oysters?

It is a species of crab (Pinnotheres ostreum) that has evolved to live harmoniously inside an oyster’s shell. These dime-sized crabs, much sought after by gourmands, are not abundant.

How do pearls end up inside of oysters?

An oyster produces a pearl when foreign material becomes trapped inside the shell. The oyster responds to the irritation by producing nacre, a combination of calcium and protein. The nacre coats the foreign material and over time produces a pearl.

Some history about oysters

The oyster has existed since pre-historic times and has a fossilized history of over 200,000 years. Oysters have been farmed since the time of ancient Rome. Oysters, rich in folklore, have always been linked with love. When Aphrodite, Greek goddess of love rose from the sea on an oyster shell and gave birth to Eros, the word ‘aphrodisiac’ was born. As everybody knows, oysters have been linked with Casanova’s success. He was rumoured to have eaten at least 50 off the breasts of his mistress every morning.


Frequently asked questions about seafood


What is “tomalley”?

Tomalley is the lobster’s liver. It turns green when cooked and is considered a delicacy.

How old is a one-pound lobster?

No one knows exactly, but aquarium studies suggest 5 to 7 years.

What is the difference between soft and hard shell crabs?

They are the same species. A soft-shell crab is one that has just discarded its shell. Crabs which have just shed their shell hide in rocks or bury themselves in sand and mud to escape predators. They emerge after the new shell hardens, a quick process.

What are the small crabs found inside oysters? Are they harmful to oysters? May humans eat them?

These are “pea” crabs. They live, often in pairs, inside the oyster shell, eating food collected on mucous strands in the oyster. Because they do cause damage to oyster mantle and gills, the crabs are considered parasites. Pea crabs are not harmful to man.

How long do shrimp live?

The life cycle varies geographically and by species. Some live as long as 6-1/2 years, others live only a year.

How big do shrimp grow?

Depending on the species, size ranges from about 1/2 inch long on the west coast of the United States, to almost 12 inches elsewhere.

Is there more than one kind of shrimp?

Numerous varieties exist, among them brown, white, pink, royal red, brine, and rock shrimp.

What do oysters and clams eat?

Called filter feeders, oysters and clams eat plankton. By pumping water through their bodies, the mollusks strain the microscopic organisms hrough their gills, which act as sieves.

What is the largest lobster ever caught?

The Massachusetts Lobstermen’s association claimed a record when they caught “Big George” in 1974 off Cape Cod. The lobster weighed 37.4 pounds with a total length of 2.1 feet.