They are called Surf Barnacles because they prefer to live in areas of medium to high energy wave action.

Small invertebrates that live inside hard circular or pyramid-like structures made from calcium-carbonate. They have eight main side plates, surrounded by many smaller ones, giving them a scaly appearance and are usually grey with a greenish tinge.

Size

20 mm high, 25-30 mm diameter.

Field Guide

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  • Species Category: Marine
  • Species origin: Other
  • Conservation status: Common
  • What to Observe

    Search area for 30 minutes and record the following:

    • Abundant: found easily with little searching

    • Frequent: found with minimal searching

    • Rare: only 1 or 2 individuals found with intensive searching

    • Not found: not present during search

    Climate Adaptations

    Surf Barnacles are under increasing stress due to ocean acidification which can weaken their calcium carbonate shells and reduce body condition. This makes them more prone to disease, predation and low reproduction. Increasing water temperature as a result of climate change will likely affect their abundance and cause a southward shift in their distribution.

  • When and Where

    When To Look

    • Throughout the year

    Where To Look

    • Southern Western Australia, South Australia, Tasmania and NSW
    • Common on rocky shores, from mid to low tide, particularly areas of high wave exposure
  • What Else?

    Similar Species

    Limpets can resemble Barnacles as both are round, pyramid-shaped and cream in colour but Limpets always have shells that consist of only one singular plate. Limpets are also free moving whereas barnacles are always fixed to a hard surface.

  • Trails: Bellarine Peninsula - Barwon Coast & Ocean Grove Nature Reserve VIC, Cape Conran VIC, Killalea State Park NSW, Randwick Coastal Walkway NSW, Ricketts Point VIC
  • Species Region: Australia