Pyura sea squirt
Pyuridae - Pyura praeputialis

What does it look like?

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.

Native to Austrialia, the Pyura sea squirt, 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.

Why is it a problem?

An aggressive competitor for space, the Pyura sea squirt 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.

Control Methods

You must notify the Northland Regional Council if you think you have seen this pest

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.

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