Perna viridis has been detected at Mornington Island, Amrun Port and Escape River in northern Queensland. These were individual detections and ongoing surveillance in these areas indicated no established populations. The Mornington Island detection was on driftwood. Please report any sightings via Report a Pest or visit Biosecurity Queensland for more information. 

P. viridis has not successfully established in Australia to date (Stafford et al., 2007). Wells, (2017) questioned whether the species is actually highly invasive in Australia given the numerous opportunities it has had to establish populations. The species was introduced into Ambon in eastern Indonesia by a ferry. Mussels on the ferry were in poor condition, having survived transit through oligotrophic (nutrient poor) waters (Huhn et al., 2015, 2017). The generally oligotrophic waters of northern Australia may be at least part of the reason why the species has not established in northern Australia (Wells, 2017).

McDonald (2012) reported a possible spawning event on a vessel at Garden Island, WA, based on growth rates from tropical and subtropical waters. An alternative explanation is that the mussels had been spawned in Asia and the growth rates depressed in oligotrophic open ocean and cold New Zealand waters where the vessel had been operating before it arrived in Australia.

Summary Description
Asian green mussels are regularly found on ships arriving from Asia, particularly in niches such as anchor wells, sea chests, bow thrusters and internal seawater pipes. A few have also been found on driftwood or settled on surfaces in northern Australian waters,especially around Cape York Peninsula and the Gulf of Carpentaria. To date they have not established in Australia.

Perna viridis is one of six species on the Australian Priority Marine Pest List (DAWE, 2020) that currently do not occur in Australia. It was also on previous national lists (NIMPCG, 2009a, 2009b) and various state and territory lists.

The species is widespread and of considerable fisheries importance in Southeast Asia. Heersink et al. (2014) reported that P. viridis is regularly found on ships with biofouling that arrive from Southeast Asian ports, a process that has been occurring for many years but increased as shipping expanded in recent years. Occasional individuals have been found in some parts of northern Australia, or small numbers on driftwood in the Gulf of Carpentaria. The mussel established a small colony briefly in Cairns in 2001 but that infestation died out naturally (Stafford et al., 2007).
Perna viridis is a large mussel, 80-100 mm in length, occasionally reaching 185 mm (Vakily, 1989). The shell tapers to a sharp, downturned beak and has a smooth surface covered with a periostracum (skin) that can be vivid green to dark brownish-green near the outer edge and olive-green near the attachment point. The ventral margin of the shell is straight or weakly concave. The interior of the shell valves is shiny and pale bluish green. The ridge which supports the ligament connecting the two shell valves is finely pitted. The beak has interlocking teeth: one in the right valve and two in the left. The wavy posterior end of the pallial line and the large kidney-shaped adductor muscle are diagnostic features of this species.

As many vessels are now cleaned before entering Australian waters, P. viridis on them are likely to be small juveniles, so their bright green colour should make them readily identifiable. The species lives on hard surfaces, such as rocks, jetties and wood. If introduced to Australia P. viridis are most likely to be found in or near ports in the northern half of the continent. It can develop dense populations, clogging pipes and fouling other industrial infrastructure.