2004, RPS Hydrosearch, Thames Array Analysis of Seabed Videos - For Presence of the Reef-Building Ross Worm, Sabellaria spinulosa series https://portal.medin.org.uk/portal/start.php?tpc=015_81b9876a8fa358418e10c774c2e2c63a Author: David Levell - RPS. The objective of this report is to review a series of seabed video files which have been obtained by Osiris Projects from sites within the proposed Thames Array offshore renewables project survey area. The review was to specifically assess whether the video footage contained any evidence of the presence of the tube-dwelling, reefbuilding marine worm, Sabellaria spinulosa. A total of 18 video files, amounting to 3.25 hours of footage were reviewed. All were obtained from sites subjected to high current speeds, large quantities of suspended organic solids within the water column and associated backscatter from the ROV camera lighting arrays. None of the video sequences contained any evidence of the presence of Sabellaria species. Subsequent to the analysis of the video footage further information on the occurrence of S. spinulosa in beam trawl samples obtained by CMACs was made available. It appears that none of the seabed video locations correspond to the sites where S. spinulosa was recorded by CMACs. It is recommended that, if the opportunity arises, the acquisition of video footage at a selection of the locations where CMACs have recorded the presence of S. spinulosa within beam trawl and macrobenthic grab samples, is attempted using a seabed ROV. This will enable the further investigation and clarification of the extent and degree of reef formation, if any, that is present within the Thames Array survey. The survey operations report is also provided. 20041018