Although they could be mistaken for a molluscs, gooseneck barnacles, (also known as goose barnacles) are actually crustaceans and are related to lobsters and crabs!
Molluscs are soft-bodied invertebrates with no backbone, and many have a protective shell, such as mussels. Crustaceans have a hard exoskeleton with legs and antennae, such as crabs.
Although they could be mistaken for a mollusc with their pipi-like shells, gooseneck barnacles, also known as goose barnacles (Lepas spp.) are actually crustaceans, and are more closely related to lobsters and crabs – they have jointed legs called cirri which they use to gather microscopic food from the water.
Why ‘gooseneck’ barnacle? When extended, a long rubbery stalk, called a peduncle, topped with shell-like valves opens, allowing the cirri to emerge. They do look a little like a goose head and neck, but the name actually comes from the Middle Ages when people thought they were the egg cases of migrating geese!
Lepas spp. species are mostly pelagic, and will attach themselves to other highly mobile species. They will also attach themselves to anything that floats in the open ocean, such as the rope in the photo above. You will also find them clinging onto driftwood and other flotsam, and even cuttlebone.
Being a stalked barnacle, and not sessile (fixed in one location) goosenecks are designed to be more flexible. They can extend into the water column and withstand wave action.
There are some species of gooseneck barnacles that live in the intertidal zone, but these are rare in metropolitan Western Australia. Intertidal zones can be a harsh environment, so to live there organisms need to be able to adapt to being out of water for a period of time, and survive a large temperature range.
Gooseneck barnacles are found in most states of Australia, including New south Wales, Queensland, South Australia, Victoria and Western Australia. They are also common in other parts of the world.
Fast facts:
- Sizes range up to 2.5 cm (in WA), age up to 20 years
- Lepas pectinata was given its scientific name in 1793
- Goose barnacles are hermaphrodites, with both male and female reproductive organs.