Darwin’s barnacle (Austrominius modestus)
Native to Australasia, Darwin’s barnacle has probably been present in the UK since 1946. It attaches to a variety of surfaces including rocks, stones, hard-shelled animals and artificial structures including ships, and tolerates a wider range of salinity and turbidity than native species. This is a fast growing species that is quick to reach maturity, which, combined with its high reproductive output in water temperatures above 6oC, gives it a competitive advantage over native species. This barnacle can dominate hard surfaces and displace native species; it has largely displaced native barnacles in estuaries in southwest England, although impacts are less significant on exposed rocky shores. In favourable conditions is can be a nuisance as a fouling organism. Spread of this species may be limited by the appropriate treatment of ships’ ballast water and removal of hull fouling communities, but is unlikely to be prevented due to the species’ ability to disperse naturally during the pelagic larval phase.
Environmental risk: LOW
Economic risk: LOW
Image: J. Bishop © MBA