Azores Barnacle – Megabalanus azoricus
The Azores Barnacle is a species in the order of Sessilia and therefore belongs to the subphylum of crustaceans. Megabalanus azoricus was first described by Pilsbry in 1916.
Description, Anatomy & Characteristics
The shape of the Azores Barnacle resembles a volcanic crater. Its colour is white to beige. It also has fan-shaped tentacles with which it filters the water.
No information on the size of the species can be found. The specimens I photographed had a diameter of 1.5cm at 2cm height.
Habitat & Distribution
Megabalanus azoricus lives on rocky ground or flotsam, such as a buoy. They are mainly found in the tidal zone, at depths of up to about 5m. They are rarely found in depths of up to 40m.
When scuba diving on the Canary Islands we can rarely observe the species.
Apart from the Canary Islands, the Azores Barnacle has a comparatively small distribution area. As their name suggests, they are widespread in the Azores and also on the coast of Portugal.
Biology & Feeding
Megabalanus azoricus lives as an adult animal sessil, so it does not change its location. Usually you will find large colonies of them.
They feed on plankton and detritus that they capture with their fan-shaped tentacles.
Reproduction & Development
The Azores Barnacle are hermaphrodite. Fertilization takes place inside the shell. When the eggs hatch, they live through several larval stages until they find a habitat and settle.