Watersipora subatra

Bryozoans

Watersipora subatra is an encrusting bryozoan, but colonies can become erect and leaf-like, with extensively overlapping calcareous crusts and curled edges. Colors range from red to black. It has been frequently confused with W. subtorquata, W. arcuata, and Watersipora n. sp. The native region of Watersipora subatra is unknown, but it is widely distributed in the temperate and tropical Pacific, from Japan and China to Northern Australia. Introduced populations in the northeastern Pacific range from Sinaloa, Mexico to Ketchikan, Alaska. In Europe, W. subatra is found from Northern Ireland to Atlantic and Mediterranean Spain. This bryozoan has a brief larval period, so hull fouling and transport with Pacific oysters are the most likely vectors.