Carpet sea squirt

Didemnum vexilum



Due to the recent destruction of structures within the marina at Holyhead, by Storm Emma, there is a concern that mobile debris will bring Didemnum vexillum (D. vex) to the eastern seaboard of Ireland. Some of the debris has turned up already on shores in Wicklow in the form of numerous small pieces of polystyrene.  However, D. vex is most likely to be found on resin or timber components of the marina structures that have been fouled with marine life. (see image below)  If you do think you have found some of the debris in question, please endeavour (safely) to prevent it from returning to the open sea by moving it to above the high tide line and then report it by entering a record at: if you are in RoI and,

at if your location is in Northern Ireland.

N.B. Please use the full species name Didemnum vexillum when entering your records online.

It will be especially helpful if you can submit photos with your record.  If necessary somebody will try to visit the site to check for the presence of D. vex.

Species Description;

Carpet Sea Squirt Didemnum vexillum is an immobile tube-like sea creature that forms colonies, mainly on hard surfaces.  It can form mats that smother other marine life.  It is difficult to identify and requires an expert to confirm identification.


             Image:Resin-coated polystyrene from Holyhead Marina. Photo credit @Paul Brazier Natural Resources Wales


Remains of floating pontoon with surface resin (Photo credit: @Ashley Williams)

Invasive Species Ireland

Invasive Species Ireland