By Vihan Dalal, Local Democracy reporter A mystery aquatic plant found in Jackson Bay has been tentatively identified as Potamilla alba, a species of marine worm. A biosecurity report tabled at the West Coast Regional Council's Environmental Management Committee says divers conducting surveillance on behalf of the council found the "unidentified species" in February this year.  Biosecurity NZ aquatic team manager Mike Taylor told Local Democracy Reporting the same species was first found at Banks Peninsula in 1951. According to the World Register of Marine Species, Potamilla alba is typically found in New Zealand waters, although this is the first time it has been identified on the West Coast. West Coast Regional Council environmental science group manager Shanti Morgan said the worms were "dead white" in colour and 75mm long, with gills up to 10mm long. They were "unlikely" to be harmful. Mr Taylor concurred, saying the species "does not represent a biosecurity concern".…