During the winter of 2003–2004 a large number of the warmer water barnacle Perforatus (Balanus) perforatus were found in North Wales well beyond the normal rocky shore range of the species. They were found attached to plastic fish boxes and other plastic flotsam stranded on beaches after storms. Evidence from markings as well as oceanographic and meteorological conditions suggests that the flotsam with the barnacles may have originated in north-western Spain. Plastic flotsam that does not readily degrade could provide a means for range extension in sessile benthic organisms such as some barnacles.
