Invasive SpeciesGreen crab

Carcinus maenas
FOUND by 2018aib
Falmouth Maine
ID Confirmed
Quality checked by Ms. Leier
Peer reviewed by Ms. Leier
Field Notes
I was looking for the green crab on Mackworth Island. It was 61ºf and I was on a rocky shore with seaweed covering every rock until it reached the water. It was a little wavy. On the seaweed, if you looked close enough, you can see periwinkles in different colors like yellow, mostly grey, and white. The seaweed was really slippery so I did not go that far off. There were clouds in the sky blocking out the sun. We did not see many crabs but the majority of the crabs we found were green crabs.
A sketch of our study site.
Supporting Evidence
Photo of my evidence.
Green crabs have thin claws and this crab has thin claws.
Photo of my evidence.
The green crab can come in different colors like brown, green, and red, the crab in this picture is brown.
Photo of my evidence.
A green crab can be as long as 10 cm wide, with a hexagon-shaped shell.
Species Observation: Species Looked For
Did you find it?: 
I think I found it
Scientific name:
Carcinus maenas
Common name:
Green crab
Sampling method: 
Photo of our sampling method.
Place Studied
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Map this species
N 43.690130 °
W -70.226560 °
Observation Site Information
A photo of our study site.
Coastal - Beach or dune
Trip Information
2018 Mackworth Coastal
Trip date: 
Thu, 2018-10-04 07:26
Town or city: 
Falmouth Maine
Type of investigation: 
Species Survey
Time of low tide: 


Great work identifying this crab! Don't forget to count the spines - that's always a big clue.