Scallops are sea-dwelling bivalve mollusk of the family Pectinidae found in many of the world’s oceans

Anatomy

Scallops have a central. large, well developed abductor muscle which allows them to swim.  They are the only migratory bivalve.  Scallops have up to 100 simple eyes appear around the edges of their shells. The eyes are reflector eyes, with a complex retina which includes two types, one responding to light and the other to abrupt darkness. They detect changing patterns of light and motion.

Food and digestion

Scallops are filter feeders, and eat plankton. Their siphons conduct water over a filtering structure, where food becomes trapped in mucus.  The cilia on the structure then move the food toward the mouth. The food is digested in the stomach and waste is passed through the intestine.

Life habits

Florida scallops are free-living and can flee from predators by opening and closing its shell.

Reproductive cycle

The scallop family consist of some species are dioecious – which means the males and females are separate, while others are simultaneous hermaphrodites – which means both sexes in the same individual, and a few are protoandrous hermaphrodites – which means they are males when young then switch to females when they get older.  A Florida bay scallop has the  ability to develop both female and male sexual organs; and the scallop produces both eggs and sperm.

A rapid change in water temperature generally brings about spawning. In Florida, most spawning occurs in the fall after the water temperature drops, or in the spring when water temperature warms.  A single scallop is capable of producing millions of eggs at once, but the mortality rate is extremely high. Only 1 egg out of 12 million may survive to adulthood.

Sperm and eggs are released  into the water during mating season and fertilized eggs sink to the bottom. In several weeks, the scallop larvae hatches and drifts in the plankton until settling to the bottom again to grow. Different species of scallops, such as the bay scallop are short lived, while others can live 20 years or more. Age can often be judged by the concentric rings of their shells.