Gooseneck Barnacle

• GeneralIt is not a mollusc but a barnacle, a crustacean, and it filter-feeds with legs modified into cirri.
• It is a crustacean, not a mollusc: it is related to crabs and prawns, even though it looks like a shell stuck to the rock. Charles Darwin proved it, devoting eight years to the study of barnacles.
• It lives head down, attached to the rock by a stalk, and feeds by extending its cirri — its modified legs — to filter the plankton carried by the waves.
• It depends on wave action: it thrives only on the most exposed points, and that makes harvesting it one of the most dangerous jobs at sea. Galician percebeiros work roped up and against the tide.
• It is hermaphroditic and needs cross-fertilisation, so it only grows in dense aggregations where individuals can reach one another.
• In Galicia the harvest is regulated by annual plans with closed seasons, quotas and rotating zones managed by the fishermen's guilds, a co-management model cited as an international example.

Skeleton type

Invertebrate - articulated calcareous exoskeleton (crustacean)

Habitat and environment

Intertidal rock in the full force of the surf

Sources consulted: https://es.wikipedia.org/wiki/Pollicipes_pollicipes; ScienceDirect (Hughes 1989); Science Advances, How colonial animals evolve; Wikipedia, Zooid

The pins mark the parks and dive sites where its presence is documented.