Have you ever seen rocks covered in barnacles along the shoreline on the North Shore? Have you ever scraped your bare foot on walking in a tide pool? It was most likely a patch of Pacific Acorn Barnacles! Although small individually, these white and light grey cone-shaped barnacles cluster together in patches on solid surfaces in inter-tidal areas. Pacific Acorn Barnacles filter feed on plankton. Once stuck to a surface, these barnacles are sessile. This means that they cannot move. Hardened barnacles can be a problem for ships because once barnacles become attached, they are very difficult to remove. They can slow down the ship and use up extra fuel.
Information from E-Fauna BC: https://linnet.geog.ubc.ca/efauna/Atlas/Atlas.aspx?sciname=Balanus%20glandula&ilifeform=106