Acorn barnacle  (Semibalanus balanoides)

Learn about the scientific name of this species and how it fits into the tree of life at Nature Navigator.

Range

Found in the north-east Atlantic from Spitzbergen to north-west Spain, as well as the Pacific coasts of North America reaching south to British Columbia, and on the Atlantic coast south as far south as Cape Hatteras. It is common around all coasts of Britain, but is rare or absent from the south-west of Cornwall and the Isles of Scilly (3).

You can view distribution information for this species at the National Biodiversity Network Gateway.

Habitat

Inhabits rocky shores of all exposures, and forms the distinct greyish-white 'barnacle zone' on the shore with species of Chthamalus barnacles. When the two occur together, Semibalanus balanoides tends to occur lower down the shore than Chthamalus. Fewer barnacles occur where seaweeds dominate the shore, as the sweeping action of the seaweed fronds removes newly settled barnacles from the rock (2).

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