What does it look like?
The clubbed tunicate has a long, club-shaped body on a short, tough stalk. Its surface is tough, leathery, rumpled, and knobbly, and its colour ranges from brownish to white, it can be distinguished from the native species, which is white to purple with a much longer stalk (2/3 to 3/4 the overall length of the animal).
Why is it a problem?
Clubbed tunicate forms dense colonies, competing for space and food with native species (e.g. mussels, oysters). It’s a highly effective filter feeder often preying on larvae of commercially important fisheries species.
It can grow rapidly, reaching densities of up to 500-1,500 individuals per square metre. It can withstand sub-zero temperatures and up to 23 degrees meaning it can invade a wide range of places.
It fouls marine farming lines, vessel hulls and other marine structures.
Control methods
Clubbed tunicate is not known to be in Hawke’s Bay, but it’s present in other regions. If you have seen or suspect the presence of clubbed tunicate, you must report the sighting to us immediately.
You can help prevent the spread of marine pests by:
- Regularly cleaning your boat’s hull – ideally keep fouling growth to no more than a light slime layer
- Applying a thorough coating of antifouling paint and keep it in good condition
- Ensure your hull is clean and free of fouling before you travel to a new area
- Clean and dry any marine equipment (e.g. ropes, lines and pots) before using in a new area
- Inspect areas on your boat that retain water for signs of marine life
- Check for aquatic weeds tangled around anchors, trailers and other equipment
Related links
Clubbed Tunicate — Clean Below? Good to go
Notify Council
If you think you've found this pest, please get in touch with our Biosecurity Team at biosecurity@hbrc.govt.nz or call us on 0800 108 838.
Management Programme
Exclusion Programme
Exclusion pest plants are organisms known in other parts of the country but are not thought to exist in Hawkes Bay. An Exclusion Programme aims to prevent a specific pest from establishing in the region before it arrives. With economic returns of around 1:100, prevention is always the most cost-effective strategy available. The faster we can detect an incursion, the more economical and successful our response efforts are likely to be. If an organisms listed under an exclusion programme was to establish, it has the potential to cause adverse effects on production, economic wellbeing, and environmental values.
More informationUnwanted Organism
An unwanted organism is any organism that's capable of causing harm to natural or physical resources (like forests and waterways) or human health. A number of introduced pests in New Zealand are classed as unwanted.
More informationRules
Plan Rule 1
The operator of a vessel entering the waters of the Hawke's Bay Regional Council must ensure the hull (includes hull area, niche areas and wind and water line) or any structure or navigation aid of any origin, is sufficiently cleaned and antifouled so that there is no more than a slime layer and/or goose barnacles
More informationSections 52 and 53 of the Biosecurity Act (1993)
No person shall knowingly communicate, cause to be communicated, release, or cause to be released, or otherwise spread any pest or unwanted organism, in accordance with Sections 52 and 53 of the Biosecurity Act 1993
More informationTaxonomies
FamilyStyeladae
TypeAnimals
GroupSea squirt
HabitatMarine
Management ProgrammeExclusion ProgrammeUnwanted Organism
RulesPlan Rule 1Sections 52 and 53 of the Biosecurity Act (1993)
