Northern Rock Barnacle
Scientific name: Balanus balanoides
Description: Northern Rock Barnacles have variable shape but are usually have a white coloured, rough, folded shell (carapace). They are often found in colonies and can grow up to sizes of 25mm.
Distribution: They are usually found in inter-tidal areas in relatively undiluted seawater, and sometimes they extend sub-tidally into shallow water.
Locomotion: Adult Northern Rock Barnacles are sessile. Their distribution depends on the movement and in the larval stages.
Food gathering: Barnacles are suspension feeders and use their “cirri” to catch food.
Gas exchange: Their gas exchange is based on simple diffusion across the thin parts of the body.
Reproduction: Northern rock barnacles are hermaphroditic and copulation is followed by internal fertilization. After hatching there is a free-swimming nauplius larval stage which is followed by a unique cyprid larval stage. After settling, the develope into an adult.
Interesting facts: Northern rock barnacles often compete with blue mussels and rockweeds for space o rocks and pilings.