Work begins to prevent spread of invasive marine species in WA waters

The Western Australia Department of Primary Industries and Regional Development (DPIRD) has begun implementing a State-wide Array Surveillance Program (SWASP) in cooperation with port authorities in Fremantle, Albany, Esperance, Geraldton, Port Hedland, Dampier, Broome, and other ports to reduce the risks of invasive species being introduced to local waters from visiting ships.

The DPIRD also managed a recent response to an invasive marine pest, carpet sea squirt (Didemnum vexillum) at Henderson, which can smother native marine species like shellfish, sea sponges and algae.

Carpet sea squirt can also foul vessels and marine infrastructure. Thus, ongoing surveillance along WA’s 11,000-kilometre coastline is being implemented as an important biosecurity measure to detect and manage any spread.

In the past year, the DPIRD has carried out biosecurity surveillance around WA with research and development into eDNA (environmental DNA) to help better detect and identify species present in water, plankton, and biofouling.

Aquatic biosecurity officers also worked under agreement with the commonwealth government to carry out surveillance at Christmas Island and the Cocos Keeling Islands.

The team also inspects and monitors freshwater locations, conducting surveillance around the state, as well as water and plankton collection for eDNA analysis. They also undertake containment and localised eradication work when there is a clear environmental benefit; however, the best form of management is prevention, so it is important that aquarium fish are not released into WA’s environment.

DPIRD Aquatic Pest Biosecurity Technical Area Manager Justin McDonald said the freshwater ecosystems of WA were historically challenged by many introduced species, which, based on currently available data, has been on a more rapid growing trajectory since the late 1990s.

"Many of the introductions stem from the global aquarium fish trade, through deliberate release or escape," Dr McDonald said. "Some fish, like carp, are known ecosystem modifiers and can have a detrimental impact on water quality and native fish populations.

"Native fish in South West WA are generally quite small and vulnerable to predation and fin-nipping by larger, introduced fish. Due to the connectivity of aquatic systems and biology of the introduced species, it is exceedingly difficult to eradicate these invaders."

Any concerns regarding aquatic pests in WA’s inland waterways and ocean environments can be reported to the 24-hour FISHWATCH hotline on 1800 815 507.