Giant Acorn Barnacle

Giant Acorn Barnacle

Balanus nubilus

Physical Description

The Giant Acorn Barnacle is one of the largest barnacle species in the region, growing up to 11 cm in diameter. It features a broad aperture relative to its base and distinct beaks on its opercular plates.


These barnacles are commonly found in clusters on rocks, particularly on isolated rocky pinnacles and wharf pilings.

Geographical Range

The Giant Acorn Barnacle is distributed from Alaska to San Diego along the eastern Pacific coast.


As filter feeders, Giant Acorn Barnacles primarily consume plankton and other organic particles suspended in the water.

Other Species