Each ring on a scallop’s shell represents a year of growth, although a ring might also record a stressfulincident in the scallop’s life.
In early Christian times, the scallop shell was often incorporated into baptismal fonts as a symbol of rebirth
The word "scallop" is derived from the old French "escalope" meaning "shell".
They are mainly found at depths of 18-46 m, preferring substrates of clean firm sand, fine gravel or sandy gravel. King scallops recess into the sediment to a level with the upper shell and sometimes they are partially covered.
Like other bivalve molluscs, scallops are filter feeders removing natural phytoplankton (microscopic algae or plant cells) and organic particles from sea water as it passes over the gills. The gills have the dual function of respiration and feeding. They act like fine, intricate nets that trap food particles from the water.
Scallops spawn in the summer and they may spawn more than once in a season. They are hermaphrodite; the proximal white part of the gonad is the male testis, the distal part of the gonad is the ovary which is bright orange in ripe scallops. Sperm are released before the eggs and this helps to prevent self-fertilisation.
Fertilisation of the eggs takes place in the sea and the resulting larvae drift in the plankton for around 3 to 6 weeks (depending on whether in southern or northern parts of the UK), feeding on microscopic algae.
When mature, the larvae sink out of the plankton, attach to stones, empty shells, bryozoans, filamentous algae and hydroids by their byssal threads and develop into the first ‘immature’ adult stage (called spat or seed) which are 0.25-0.4 mm shell length.
Later, they detach again to live on the seabed. They remain mobile as adults and can swim short distances by clapping the shell.