CCW tackles invasive sea squirt in Holyhead harbour
The Countryside Council for Wales has started
work to eradicate an invasive sea squirt in Holyhead harbour, which
is threatening to smother native marine life in Wales.
the alien invader...carpet seasquirt
Photo by Ronan Holt©CCW
The carpet sea squirt (Didemnum vexillum), which originates from
Japan, has established itself on the marina’s floating pontoons and
mooring chains and mooring buoys in the harbour.
If left unchecked, it could spread rapidly, colonising natural
habitats and threatening the important mussel industry in the Menai
The carpet sea squirt has had devastating impact on marine life
in other parts of the world where it has been accidentally
introduced, such as New Zealand.
There, it has literally carpeted acres of sea bed, making these
areas unsuitable for native marine plants and animals.
The sea squirt was most likely brought into Holyhead harbour on
the hulls of leisure craft. The Countryside Council for Wales made
a pilot attempt to clear the seasquirt in the winter 2009. Now,
building on this experience, CCW’s marine staff will be working
intensively to completely eradicate the creature.
The work involves fixing massive bags around the underwater
structures of the marina. By stopping clean flows of water from
reaching the sea squirts, they will suffocate and die. If
eradication techniques are successful here, CCW could advise other
affected areas in the UK on how to get rid of the species.
The owners of Holyhead Marina are supporting CCW’s efforts. The
target is to completely rid the harbour of sea squirt by spring
2012 before it can spread more rapidly in the spring and
Diver fixes massive bag to smother the invasive
seasquirt-Holyhead marina. Photo by Ronan Holt©CCW
Rohan Holt, CCW marine biologist managing the project said: “If
we successfully eradicate the sea squirt, we will work hard to make
sure that it does not recolonise. This will mean careful monitoring
in Holyhead marina and other marinas and popular mooring areas
throughout Wales to check that it hasn’t reappeared.
“Guidelines for small boat owners on how they can help will be
an important part of this, as well as regular checks.”
Have you seen this creature?
- Didemnum vexillum is a spongy textured sea squirt with a
leathery feel. It does not feel slimy.
- It is a distinctive mustard or pale orangey/yellow or beige
- It often appears like pale flat patches or wax dripping from
artificial structures just below water level;
- Its surface has leaf-like veins with tiny pores.
This project is funded by the Welsh Government.
Contact the Countryside Council for Wales’ Enquiry Unit for more
NOTES TO EDITORS
For further information, please contact Helen Evans, CCW PR
Officer on 01248 387377 or 07717225589. email@example.com; or Brân
Devey on 02920 772 403; 07747767443 or firstname.lastname@example.org .
The Countryside Council for Wales is a Welsh Government
Sponsored Body, working for a better Wales where everyone values
and cares for our natural environment. More information about our
work is available on www.ccw.gov.uk