Great Scallop

• It is a simultaneous hermaphrodite, with a single gonad that is part male and part female at once.
• It can 'jump' by clapping its shells together to expel water and escape a predator.
• A three-year-old female can release as many as 21 million eggs in a single spawning.

Skeleton type

Invertebrate - external calcareous bivalve shell

Habitat & environment

Sandy and gravel bottoms of the north-eastern Atlantic and the Mediterranean, between 0 and 125 m deep

Birth weight

A microscopic egg; a trochophore larva after external fertilisation

Size at birth

A microscopic planktonic larva that turns into a veliger (a miniature clam) after several weeks

Sexual maturity

2-3 years, on reaching 80-90 mm of shell length

Gestation / incubation

No gestation; over a month as a planktonic larva after external fertilisation

Litter / clutch size

Up to 15-21 million eggs released by a 3-year-old female at each spawning

Sources consulted: SeaLifeBase; MarLIN (biology and sensitivity review); ScienceDirect Topics; Animalia.bio; The Wildlife Trusts; Institute of Marine Research (Norway); Aquarium La Rochelle; Grokipedia (Pecten maximus)

Best time: All year round on sand and gravel bottoms of the north-eastern Atlantic, between 10 and 100 m deep; spawning is concentrated in spring and summer.