Northern Pacific Seastar (Asterias amurensis)
Key features
The Northern pacific seastar is an Australian Priority Marine Pest.
Key features of the Northern pacific seastar include:
five arms with pointed unpturned tips
yellow or orange with purple markings, yellow underneath
up to 50 cm across when fully grown.
Impacts
The Northern pacific seastar:
is an aggressive predator of native and commercial species including mussels, oysters and scallops.
harms biodiversity, aquaculture and fisheries.
Habitat
bays, estuaries and reefs from high tide mark to 200 m deep
found in a range of habitats including mud, sand, seagrass, mussel beds, artificial structures (marinas, ports, etc.), rock pools and rocky reefs.
Distribution
The Northern pacific seastar:
is an established pest in Tasmania and Victoria
was first introduced into Tasmania in the 1980s
has been recorded from Banks Strait in the north of Tasmania to Recherche Bay in the south. The highest population densities are found in sheltered bays in south east Tasmania, particularly the Derwent Estuary.
Further information on the Northern pacific seastar can be found on NIMPIS.
Asian Kelp / Wakame (Undaria pinnatifida)
Key features
The Wakame is an Australian Priority Marine Pest.
Key features of Wakame include:
green to golden-brown colour
smooth, thin blades that stop well before the kelp's base
obvious strap-like midrib along length of blade
ruffle near base
up to 1 m long, but can be 3 m
usually found in cooler months.
Impacts
The Wakame:
Habitat
shores and shallow waters, from low tide up to 20 m deep
sheltered, rocky areas, reef, artificial structures (marinas, moorings, etc.) and aquaculture equipment.
Distribution
The Wakame:
is an established pest in Tasmania and Victoria
was first reported from eastern Tasmania in 1988, but may have been present since 1982
is a common species along the east coast of Tasmania, growing in large numbers around areas in which sea urchins have depleted stands of native algae.
Further information on Asian kelp / Wakame can be found on NIMPIS.
European Green Crab (Carcinus maenas)
Key features
The European green crab (also known as the European shore crab) is an Australian Priority Marine Pest.
Key features of the European green crab include:
green or brown shell with pale orange underside
five spines on each side of eyes
back legs are sharp and slightly flattened at tips
no swimming paddles on back legs
smooth shell, up to 7 cm wide.
Impacts
The European green crab:
is an aggressive predator of native and commercial species
competes with native species for food and space
can alter the structure of benthos, eelgrass and bivalve communities through burrowing and feeding activities.
Habitat
burrows in mud or sand
shores and shallow water, up to 60 m deep
found in sheltered estuaries and bays, mudflats and rocky reefs.
Distribution
The European green crab:
is an established pest in Tasmania, Victoria, New South Wales and South Australia
was first reported in Tasmania in 1993
is found on the northern and eastern borders of Tasmania, including Georges Bay, Henderson Lagoon, Little Swanport, Maria Island and Blackmans Bay. Localised range expansions have been recorded, including on the western coast of Tasmania.
Further information on the European green crab can be found on NIMPIS.
Soft-Shelled Clam (Mya spp.)
Key features
Key features of the Soft-shelled clam include:
chalky white, rough shell
shells may be discoloured in black or red mud
thin, brittle, oval-shaped shell
different shells - one has a large scooped out projection at the hinge, the other has a pit
gapes at both ends when closed
uneven growth lines
grows up to 15 cm
both species (Mya arenaria and Mya japonica) are very similar.
Impacts
The Soft-shelled clam:
competes with native clams for space
can reduce food availability for oysters, mussels and scallops
can change the characteristics of sediments and the composition of bottom-dwelling communities.
Habitat
Distribution
The Soft-shelled clam is an established pest in eastern Tasmania.
Further information on the Soft-shelled clam can be found on NIMPIS.
Pacific Oyster (Magallana gigas)
Key features
Key features of the Pacific oyster include:
Impacts
The Pacific oyster:
Habitat
Distribution
The Pacific oyster was intentionally introduced to southern Tasmania in the mid-1990s and is now a well established pest.
Further information on the Pacific oyster 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:
Record 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.