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Introduced Marine Aquatic Invaders - a field guide
Introducted Marine Species - Green Crab
Carcinus maenas
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| Green Crab - Carcinus maenas Photo: CSIRO Marine Research |
Australia Invasion
- Tasmania, Victoria, New South Wales, South Australia and Western Australia
- discovered in Western Australia during 1965, in the Swan River, but no recent records of sightings
Habitat
- protected marine embayments and estuaries
- migrate between subtidal (to 6 metres) and intertidal zone
- seagrass, clean sand, mud or under rocks
- crab shells may be found washed up on local beaches
ID Features
- two claws and eight legs
- no flattened swimming flippers
- three spines between the eyes and five spines either side of the eyes
- colour green and black through to orange and red, although small juveniles can be much paler in colour (almost sand coloured)
- carapace up to 8 cm wide, but commonly 5 to 6 cm
- deeply sculptured broad triangular-shaped carapace which covers the back of the body
More information
More detailed information on this Marine Invader is available here.
...More Information on this Invader
Similar Native Marine Species
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| Sand Crab - Ovalipes australiensis Photo: Australian Marine Life, G Edgar |
Sand Crab - Ovalipes australiensis
- sandy beaches
- flattened swimming flippers*
- grey in colour with two red oval patches towards the rear*
- carapace up to 10 cm wide
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| Red Swimmer Crab - Nectocarcinus tuberculosus Photo: Australian Marine Life, G Edgar |
Red Swimmer Crab - Nectocarcinus tuberculosus
- shallow, exposed rocky areas and reefs
- no flattened swimming flippers but rear legs wider than in Green Crab
- reddish-brown in colour and claws with black tips*
- four spines either side of eyes*
- small notch along front edge of carapace, midway between eyes*
- carapace up to 9 cm wide and covered in tough hairs
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| Nectocarcinus integrifrons Photo: Melissa Hewitt/ WA Museum |
Nectocarcinus integrifrons
- sheltered seagrass and seaweed
- no flattened swimming flippers, but rear legs wider than in Green Crab
- front half carapace purple-brown colour and rear half light brown (picture of preserved specimen which has lost colour)
- four spines either side of eyes*
- carapace smooth between the eyes*
- carapace up to 8 cm wide and covered with tough hairs
* distinguishing feature
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