Common Barnacle Balanus perforatus
These sessile crustaceans live in big populations along the shoreline and have hard conical shells. They can be seen all year round, particularly along the Norfolk coast.
Conservation status in Norfolk
Barnacles are not presently threatened.
How to help
The marine environment is under pressure and by supporting campaigns for better protection of marine ecosystems we can help the common barnacle and other marine invertebrates. You can also help by joining the Wildlife Trust Living Seas campaign.
David North
Information on the Common Barnacle
How to recognise
Barnacles are sessile crustaceans that live in large populations along the shoreline. They have a hard conical shaped shell which is made up of overlapping plates. They are able to glue themselves to different substrates such as wood, rock, and boats etc. where they live a sedentary lifestyle. Barnacles are able to open their shells allowing them to expose their fan shaped limbs known as cirri. These move rhythmically in the water sweeping up suspended food particles in a sieve like fashion. When disturbed they will quickly withdraw their limbs back into their shells to avoid any potential danger. The common barnacle is up to 2cm in diameter.
Where to see
Barnacles are very common all along the coast of Norfolk. They live on the shore zone and can often be seen at low tide on rocks and other strata.
Did you know?
Barnacles are hermaphrodites but at mating time take on the role of either male or female. The female stores the eggs until they hatch and are released as free swimming larvae known as nauplii which form part of the plankton population. After several moults the larvae fixes itself head first to a rock and metamorphoses into the adult form.
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