Situation update
Throughout the past two years, DPIRD worked with the Australian Government Department of Defence, the Department of Agriculture, Fisheries and Forestry, Fremantle Port Authority and local stakeholders to respond to the detection of CSS.
The CSS response has now transitioned to management after a 12-month transition to management phase following the determination at the national level that it was not feasible to eradicate CSS from Australia.
The Quarantine Area Notice issued on 15 March 2024 for the Australian Marine Complex Common User Facility (AMC CUF) and BAE Systems Australia Pty Ltd is no longer in place, however, CSS remains a noxious fish under the Fish Resources Management Act 1994 (FRMA) and a declared pest under the Biosecurity and Agriculture Management Act 2007 (BAM Act).
During the emergency response phase of the CSS incident, CSS was assigned a control category of C1 – Exclusion for the whole of the state except for the area surrounding the known incursion sites within Cockburn Sound. The control category for the Cockburn Sound area has been amended to C3 – Management. The C3 area map and supporting Management Guidelines can be found to the right-hand side of this page under Documents.
About Carpet sea squirt
CSS is native to east Asia, likely Japan, and has been introduced to New Zealand, North America and Europe.
CSS is a marine invertebrate animal that can overgrow and smother native species. It can overgrow rocks, shellfish, sea sponges and man-made structures such as wharves, jetty pylons, pontoons, buoys and vessels.
What can I do to prevent CSS from spreading in WA?
Recreational boaters, fishers and divers can assist in stopping the spread of marine pests and aquatic disease by keeping their boats, trailers, wetsuits and equipment clean.
When you clean your equipment, make sure that any bait, debris and seaweed is removed and not returned to the water. Check wheel arches on trailers, boat propellers, fishing tackle and footwear. Do not clean in the water or allow run off to enter the ocean.
Use soapy water to clean your boat and trailer, fishing rods and other equipment, and allow them to dry completely before using them at another location, even if it is on the same day.
There are many native species that look like carpet sea squirt so expert taxonomic identification and molecular techniques are required to confirm the identity of the species.
If you find unusual marine species attached to vessels, sub-merged infrastructure or in the marine environment in Western Australia, report it to Aquatic.Biosecurity@dpird.wa.gov.au.
More information
A carpet sea squirt factsheet and FAQ documents are available for download. More detailed and technical information on CSS is found at the National Introduced Marine Pest Information System (NIMPIS).
Contact information
Phone 1800 815 507 (FishWatch 24-hour hotline)
Email Aquatic.Biosecurity@dpird.wa.gov.au