The invasive bryozoan, Tricellaria inopinata d'Hondt & Occhipinti Ambrogi, 1985 was first recorded in European waters in the early 1980's and has since been reported from 166 locations from the Mediterranean Sea to the north-east Atlantic coastline. This species is typically associated with human activity, including commercial and recreational vessels and aquaculture, where it has been found in abundance on boat hulls and propellers, floating pontoons and structures associated with shellfish cultivation. Tricellaria inopinata has a high tolerance to a wide range of salinities and temperatures, although following the harsh winter of 2010, populations disappeared in Germany suggesting that this species is near the northern limit of its range under current climatic conditions. It is expected to continue to disperse though, throughout the Mediterranean, English Channel, North and Celtic Seas.