Routine DNA barcoding of Canadian Gracilariales (Rhodophyta) reveals the invasive species Gracilaria vermiculophylla in British Columbia.

As part of an extensive DNA-based floristic survey of marine macroalgae in Canadian waters, an unexpected sequence for a Gracilaria sp. was generated from British Columbia. Before further molecular analyses and corresponding morphological/anatomical observations this mystery sequence was temporarily entered into our database as Gracilaria BCsp. Continued sampling uncovered this species from four additional locations. A timely collaboration with international colleagues introduced sequences from the invasive Gracilaria vermiculophylla into our cytochrome c oxidase I alignments - these a perfect match to BCsp indicating that this species occurs in British Columbia. A discussion of the origin of this taxon in Canadian waters, whether natural or introduced, is provided.