Bivalves · Arcida · Arcidae

Noah's Ark

Arca noae

Not Evaluated

It has not yet been assessed against the IUCN criteria. See full glossary

Noah's ark clam is a bivalve mollusc of the family Arcidae. This bivalve species is marine.

Size

5 cm – 9 cm

Lifespan

15 years

Diet

Omnivore

Combines animal and plant food depending on availability.

Social structure

Colony

Lives in large concentrations, often for breeding reasons.

Sighting difficulty

Unknown

Fun facts

It is eaten raw on the Dalmatian coast, where it is considered a delicacy, and its outline recalls a ship's hull, which is where the name Noah's ark shell comes from.
Unlike most bivalves, its blood contains haemoglobin, which gives its tissues a reddish colour.
The name comes from its outline: seen edge-on, the paired shell suggests a decked boat, or Noah's ark.
It has pallial eyes along the edge of the mantle, mostly at the rear, which detect shadows and warn it of a predator.
It is a protandrous hermaphrodite: it matures as a male and may change sex later.
Its shell is a remarkable material: one of the most complex and compact biomineral forms among molluscs, with little organic matrix and excellent resistance to bending and fracture.
It was hugely abundant in the Adriatic until the Second World War. A catastrophic, unexplained collapse in 1949 and 1950, and bottom trawling afterwards, drove it down; it has recovered slowly since, and in 2002 densities of up to 13 individuals per square metre were recorded.

Habitat & environment: Rocks and boulders of the Mediterranean and the nearby Atlantic, from 0 to 60 m
Sexual maturity: Matures at two years old

Sources consulted: https://es.wikipedia.org/wiki/Arca_noae