Carpet Sea Squirt (Didemnum vexillum)
Key features
Didemnum vexillum AKA the carpet sea squirt (CSS) is listed on the National Priority List of Exotic Environmental Pests, Weeds and Diseases (EEPL).
Key features of CSS include:
Impacts
CSS can:
Overgrow man-made structures such as aquaculture equipment, vessels, buoys, pontoons, jetty pylons and wharves
Grow over mussels and oysters
Modify habitats
Compete with native species for space and food.
Habitat
CSS inhabits:
Marine waters
Fully submerged hard structures
The lower intertidal region of estuaries
It prefers cooler temperate waters.
Distribution
CSS is not found in Tasmania
It has become established in ports in Western Australia (Garden Island and Henderson) and in New South Wales (Sydney).
Further information on Didemnum vexillum can be found on NIMPIS.
Chinese Mitten Crab (Eriocheir sinensis)
Key features
The Chinese mitten crab is an Australian Priority Marine Pest.
Key features of the Chinese mitten crab include:
furry 'mittens' on claws
smooth, squarish shell up to 8 cm wide
four sharp spines in between eyes
brownish-orange-green shell with four spines along each side.
Impacts
The Chinese mitten crab:
competes with native species for space and food
causes erosion by burrowing into river banks and shorelines
damages aquaculture
can host liver fluke which harms human health
can carry several crustacean diseases including crayfish plague.
Habitat
freshwater rivers, estuaries and coastal areas
favour compacted clay-silt banks with some vegetative cover.
Distribution
The Chinese mitten crab is not known to be in Australia.
Further information on the Chinese mitten crab can be found on NIMPIS.
Black-Striped False Mussel (Mytilopsis sallei)
Key features
Key features of the Black-striped false mussel include:
unequal sized shells - one side overlaps the other
smooth, small and easily crushed
grows up to 2.5 cm long
forms dense clusters
sometimes zig-zagged or stiped.
Impacts
The Black-stiped false mussel:
causes major fouling on wharves, marinas, vessels, seawater systems and aquaculture equipment
displaces native species.
Habitat
shallow waters, up to a few metres deep
estuarine to open marine waters
subtropical to tropical waters
attaches to hard surfaces like rocks, vessels, wharves, and intake pipes.
Distribution
The Black-striped false mussel was discovered in Darwin in 1999 but was later eradicated. Since then, the species has not been found in Australia.
Further information on the Black-striped false mussel can be found on NIMPIS.
Brown Mussel (Perna perna)
Key features
The Brown mussel is an Australian Priority Marine Pest.
Key features of the Brown mussel include:
dark brown
smooth shell with evenly spaced grooves
straight and long hinge
shell thin at edges and thickens towards narrow end
around 9 cm long, but can be 5 to 17 cm long
forms dense colonies.
Impacts
The Brown mussel:
Habitat
shores and shallow waters up to several metres deep
attaches to hard surfaces like rocks, wharves, marinas and port infrastructure, but may form colonies on soft surfaces.
Distribution
The Brown mussel is not present in Australian but it is occasionally detected during on arrival vessel inspections.
Further information on the Brown mussel can be found on NIMPIS.
New Zealand Green-Lipped Mussel (Perna canaliculus)
Key features
The New Zealand green-lipped mussel is an Australian Priority Marine Pest.
Key features of the New Zealand green-lipped mussel include:
around 10 to 17 cm long but can grow up to 24 cm
bright green to dark brown shell
thin reddish-brown coloured rays on shell
smooth shell with evenly spaced grooves
shell thin at edges and thickens towards narrow end
long, straight hinge line.
Impacts
The New Zealand green-lipped mussel:
Habitat
shores and shallow waters
attaches to hard surfaces like rocks, wharves, vessels, marinas and port infrastructure.
Distribution
The New Zealand green-lipped mussel is not present in Australia, but it has been detected on vessels on numerous occassions and much less often, growing in the environment.
Further information on the New Zealand green-lipped mussel can be found on NIMPIS.
Harris' Mud Crab (Rhithropanopeus harrisii)
Key features
The Harris' mud crab is an Australian Priority Marine Pest.
Key features of the Harris' mud crab include:
greenish-brown to olive green
white-tipped, unequal sized claws
hairy abdomen
four spines on each side of body
shell about 1 to 2 cm wide.
Impacts
The Harris' mud crab:
competes with native species
can spread crustacean diseases
fouls water intake pipes
damages commercial catch in fishing nets.
Habitat
shallow brackish, fresh or marine waters
rocky, muddy or sandy environments, under rocks and stones, in vegetation and oyster beds and in water.
Distribution
The Harris' mud crab is not known to be in Australia.
Further information on the Harris' mud crab can be found on NIMPIS.
Report a marine pest sighting
If you think you've seen a marine pest that is not known to the location:
Report the location through a screen shot of your location on a map, or the exact address, or GPS coordinates, or enable geo-tagging on your camera.
Take a photograph of the suspected marine pest. If possible: take multiple photos from different angles; include an object for size reference; take a photo in situ, including some habitat.
Report the sighting to the Invasive Species Branch.