Pyura
Pyura stolonifera praeputialis
Pyura (known in its native Australia as Cunjevoi)
This species is in New Zealand. It has been detected growing on rocks near Cape Reinga in the far north.
If you suspect you have found this organism in any other location in New Zealand, please report this by calling 0800 80 99 66.
Pyura
Photo: Bruce Hayward
Description
Pyura (known in its native Australia as Cunjevoi) is a marine animal known as an ascidian (a type of sea squirt). Individual Pyura live in dense colonies or groups which form a mat over rocks and are often highly visible at low tide. Pyura adults are comprised of a sack-like body, with a brown, leathery skin.
There is sometimes sand and shell material incorporated into the outer skin, and other sea life such as sea lettuce can grow in and around the individuals. The body is supported by a thick, tough stalk which attaches the whole animal to the rocks and other hard surfaces. Each individual has two siphons or holes for inhaling and exhaling water. Adults grow to about 15 cm or more in height and around 3 - 5 cms in diameter.
Pyura at low tide, Te Werahi Beach
Photo: Bruce Hayward
Habitat - where Pyura is found
Pyura can be found in rocky intertidal and shallow tidal areas growing on rocky surfaces.
In New Zealand populations have been identified on Twilight and Te Werahi beaches near Cape Reinga in Northland. It is also present in Australia, Chile and South Africa.
There are other species of Pyura and stalked sea squirts that are native to New Zealand - e. g. Pyura pachydermatina - which is subtidal in cooler temperate waters and is known as 'sea tulip'.
Impact
The species forms dense populations or mats, and can survive in a wide geographical range. In its native Australia, it occurs from southern Queensland to Western Australia and Tasmania. The species is also found in Chile where in one area, it has become the dominant organism of the lower rocky shore.
Its likely impact in the New Zealand environment is not known, but as it is an aggressive invader in Chile, there is concern that should it spread, it could displace important native New Zealand species, including green mussels. There are also concerns Pyura could be inadvertently spread to marine farms.
MAF Biosecurity New Zealand response
MAFBNZ’s priority is to determine the size and spread of the population to inform potential management action. A delimiting survey to scientifically assess the extent of the Pyura population will be underway as soon as practical (as at September 2009).
Pyura on rocks at Twilight Beach.
Note organisms squirt water when compressed.
Photo: Bruce Hayward
What can I do?
Pests such as Pyura can be spread from location to location on fouled boat hulls. Please ensure you keep your moored boat’s hull clean and your antifoul coating in good condition.
Until more is known about Pyura and how much of a pest it is in New Zealand, MAFBNZ advises that it is not touched or moved as this may further spread the population.
If you believe you have seen Pyura in any other location, please advise MAF Biosecurity New Zealand on 0800 80 99 66.
Page last updated: 30 October 2009