The carpet sea squirt (Didemnum vexillum) is a rapidly spreading marine animal that forms large colonies. These colonies attach to infrastructure, rocks and grow over and smother other marine organisms like algae, shellfish, and sea sponges. Typically yellow in colour, the carpet sea squirt may also appear pink, tan, or pale orange with rope-shaped tendrils. Despite its sponge like leather texture, it is not slimy to touch.
This highly resilient species can tolerate a wide range of water temperatures and is able to quickly establish in new environments.
While thought to be native to Japan, this invasive species has now spread to the northeast pacific, USA, New Zealand, the Netherlands, northwest France, Ireland, the United Kingdom and recently Australia.
Carpet sea squirt was first detected in Australia at Garden Island in Western Australia in 2021. Last year there was another detection in Western Australia, Henderson and followed by a detection in Sydney harbour.
While carpet sea squirt cannot be eradicated from Australia, it is possible to help limit its spread by adopting strong biosecurity practices such as cleaning and drying your fishing, boating and diving gear after use and regularly cleaning your marine vehicle. If you see something unusual, report a marine pest sighting.
Find out more about Australia’s response activity by visiting the outbreak website.
