Eudistoma elongatum
Eudistoma elongatum
Eudistoma elongatum
This marine pest is established in Northland.
Photo: Hugh Blomfield
- Eudistoma elongatum factsheet
(262 KB) - Technical report: Biology and ecology of the introduced ascidian Eudistoma elongatum, and trials of potential control options (3061 KB)
Description
Eudistoma elongatum is an Australian native ascidian or type of sea squirt which forms large colonies or groups that attach to hard surfaces.
It looks like clusters of white or cream coloured tubes or 'sausages'. Each rope or 'sausage' is actually a cylinder or tunic, containing numerous small individuals.
The long cylindrical heads are generally between 5 - 30cm long, but in some instances up to 1.5m, and 5-20mm in diameter.
The white tunics contain many small individual organisms and can sometimes appear orange flecked due to the bright orange colour of larvae within them.
This type of sea squirt is generally found in muddy bottomed tidal habitats and on man-made structures such as wharf piles, aquaculture equipment etc. It is generally submerged just below the waterline, but can often be seen at low tide.
It appears Eudistoma elongatum reduces in volume during the winter months, but once water temperatures lift it reappears in large volumes, usually over the summer.
Impact
Eudistoma elongatum has only recently been raised as a concern with Biosecurity New Zealand. It was first reported in New Zealand in early 2005, but was not regarded as an issue at that time given its low density and the fact that it appeared to die off over winter. It is not regarded as a serious nuisance to the aquaculture industry or the environment in its native Australia.
In the summer of 2007/08 the species became more prolific in a number of Northland locations and has continued to appear each year over the summer months. See below for locations.
Spread
Eudistoma elongatum has been reported on several marine farms on Northland's east coast - at Houhora and Parengarenga harbours, as well as in Waikare Inlet, Orongo and Paroa Bays within the Bay of Islands. In the Bay of Islands it has also been reported from rocks near the entrance to the inlet at Waikino Creek, Okiato Point and Paihia.
Images
Photo: Margaret Rasmussen
Photo: Hugh Blomfield
Page last updated: 12 November 2010