Britain's Rarest Coral On One of Britain's Most Popular Wrecks

Hoplangia Durotrix

August 2002 saw Newbury Sub Aqua Club members enjoying their “Purbeck Week” which was a week of diving both new sites and old favourites. Mike Markey, of Poole Bay Archaeological Research Group, and Peter Tinsley, of Purbeck Marine Wildlife Trust, joined the group for the Thursday dives. Together they discovered a site on Kimmeridge ledges of a coral which, despite its common name, had not been seen in Dorset since 1994. Unfortunately the positions of the divers were not taken during the dive so only the point where they entered the water was recorded and therefore an estimate had to be made as to where it was found and the sample they obtained was lost.

Hoplangia Durotrix or Weymouth Carpet Coral is a tiny (4 mm across) coral not unlike a cup coral, but with a habit of growing in large colonies and “carpeting” the ceiling of caves in limestone areas. Peter & Mike had described this in great detail following their find.

The following day an NAS and NSAC member was introducing a diver in his first season to the Black Hawk, a much blown up WW2 Liberty Ship which lies in Worborrow Bay. It was a complete surprise to look under some buckled plates and above their heads was something that was very much like what Peter & Mike had described the day before. They took a sample for verification then sketched the plates in the area and how to find the coral using the shot and line as a reference. This had been put in on a position measured by differential GPS (standard equipment on NSAC project dives).

Thanks to their diligence not only was Peter able to confirm that it was indeed Hoplangia Durotrix, but marine biologists with Seasearch were able to return to the site and add it to their records. It is now common practise to track divers with the GPS on project dives as we never know what we might find.