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The pyura sea squirt has a sack-like body with a brown, or reddish-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 on and around them. Adults grow up to 15 cm or more in height and around 3–5 cm in diameter.
The pyura sea squirt is native to Australia. It generally inhabits the low- to mid-intertidal zone as well as shallow subtidal areas less than 12m deep. In New Zealand, it mainly colonises rocky platforms and outcrops, rock pools and the underside of rock overhangs, but it is also found on artificial structures such as oyster farms and wharf piles. Aggregations are often in very exposed areas with strong wave action.
The pyura sea squirt is an aggressive competitor for space and has the potential to significantly alter the structure and composition of intertidal communities. Dense mats have already engulfed and displaced native green-lipped mussel beds in some areas of the Far North.
Pyura sea squirts are hermaphrodites and are believed to self-fertile. They release both eggs and sperm into the water column where fertilisation and development of the embryos occurs. The larvae hatch approximately 12 hours after fertilisation and are free-swimming for 1-3 hours before they settle.
Please contact the Northland Regional Council if you think you have seen this pest.