Edible Sea Urchin

• It is the only sea urchin listed as Near Threatened by the IUCN.
• It scrapes algae off rocks with its Aristotle's lantern, made up of five calcareous teeth.
• A large female can release as many as 20 million eggs.
• It is the largest sea urchin on European coasts, with a test that can exceed 17 cm.
• Its grazing is intense: it keeps the rock clear of algae, and where it abounds it prevents kelp forests from establishing. A rise in its population can turn a kelp forest into an urchin barren, the same mechanism documented in the Pacific with the purple sea urchins.
• It scrapes the rock with its Aristotle's lantern, a chewing apparatus of five teeth that grow continuously to offset the wear.
• Its empty test, pink and spherical, is a much-collected object, and fishing for food and for the shell trade has reduced it in accessible areas.
• The IUCN classifies it as Near Threatened, something unusual for a sea urchin, precisely because of that pressure.
• It is protected in the United Kingdom under wildlife legislation in some areas.

Skeleton type

Invertebrate - rigid calcareous endoskeleton (echinoderm)

Habitat & environment

Rocky coastal bottoms of the north-eastern Atlantic, from Iceland and Norway to Portugal, down to 1,200 m

Birth weight

A tiny egg released into the water by external fertilisation

Size at birth

A planktonic echinopluteus larva after hatching, developing over 45-60 days in captivity

Sexual maturity

Not precisely known (fast growth in the first year, slowing markedly afterwards)

Gestation / incubation

45-60 days of larval development in captivity

Litter / clutch size

Up to 20 million eggs in a large female

Sources consulted: SeaLifeBase; Diving Guru; EBSCO Research Starters; Wikipedia (European edible sea urchin); MarLIN; CABI Compendium; Animal Fact