May 15, 2026
.jpg)
Austrominius modestus, commonly known as the Beaked Barnacle, is also known as New Zealand's Barnacle and Darwin’s Barnacle. The species was first described by Darwin (Charles Darwin) in 1854. They are native to the Australasia continent (including Australia and New Zealand), and were first sighted between 1940-1943 in Britain, in Chichester Harbour, Hampshire. On iNaturalist, there are currently over 1,900 research-grade observations, and on the Global Biodiversity Information Facility (GBIF), over 14,000 observations.
To accurately identify them, you must examine the number of outside plates and the shape of the operculum (the central opening). Because several barnacle species share similar plate numbers it is vital to observe whether the plates are of uniform size or if specific ones are significantly larger.
Due to their small size- average of 1cm in diameter, a high-quality camera or macro lens is essential to capture the detail required for a Research Grade identification on iNaturalist.
.png)
Austrominius modestus is commonly found in rock pools along the mid- and lower-shore, as well as in subtidal waters. Alongside being found in seawaters, they are found in estuaries, therefore tolerating wider salinity levels compared to most barnacles.
Worms, whelks, winkles, fish, birds, crabs, and some sea slugs and starfish.
Austrominius modestus, the same as it’s relatives, are filter feeders, feeding on microscopic bacteria, plankton and more! They are vital for keeping our oceans clean. The filer the water by using their cirri, which are fan-like structures, as shown from the video below:
They have adapted to continuously breed throughout most of the year, and in peak conditions (24°C) they release broods every 10 days! This species is very fast-growing, making it outcompete slower-growing native barnacles. As planktonic larvae they are transported by water currents or by ships (through ballast water). They live as plankton for about a month before settling on rocky substrates or man-made structures such as buoys.
Austrominius modestus are native to Austrialia and New Zealand, and spreading across West of Europe.
For the most up-to-date distribution records, see:
Modest barnacle (Austrominius modestus) - MarLIN - The Marine Life Information Network - Europe (mostly UK) database of species occurrence (best for historical records).
Austrominius modestus (Beaked Barnacle) · iNaturalist- most up to data records of the current species occurrence worldwide.
NNSS (2012) Darwin’s barnacle Austrominius modestus. GB non-native species secretariat. [Online] Available from: https://www.nonnativespecies.org/non-native-species/information-portal/view/1301 [Accessed 6 May 2026]
