Invasive SpeciesGreen crab

Carcinus maenas
FOUND by 2018cdf
Falmouth Maine
ID Confirmed
Quality checked by Eliza S
Peer reviewed by
Field Notes
On Thursday, October 4, our crew traveled to Mackworth Island on our search of invasive species. It was partly cloudy and misty with a temperature of 65 degrees. That morning A and C blocks traveled to the beach to try to find the species that they were assigned. Each group got an approximate 10x10 meter zone were they tried to find the species we had. Our study area was 43.4125 latitude and -70.1337 longitude. My zone was on a point and everything I could see was covered in rockweed. That was the place I found my species, under the rockweed and under the rocks. My species was Carcinus Maenas, more commonly known as the Green Crab. I found 17 Green Crabs that morning, I knew they were green crabs because they had a pentagon-shaped carapace, 5 spines on either side of each eye, and had thin claws also have very thin sharp-pointed legs. The green crab looked to be having a negative impact on that ecosystem. This was because I saw it eating a mussel and there were only approximately 1/10 of the mussels alive in the area. The green crab is very hazardous to this habitat and if someone does not eradicate them soon then this ecosystem will be in trouble.
Supporting Evidence
Photo of my evidence.
The first characteristic of a green crab is 5 spines on either side of each eye. This is different from a similar species the rock crab because that crab has 8-10 spines beside each eye.
Photo of my evidence.
The second characteristic of a green crab is the pentagon-shaped carapace. This is different than similar species the rock crab because that crab has an oval carapace.
Photo of my evidence.
The last piece of evidence I found was the shape of claws. The green crab's claws were thin and very sharp. This is different from its similar species the rock crab because that crabs claws are thick and bulky.
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 43.412500 °
W -70.133700 °
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: 


I liked how you used the pentagon to show the shape of the shell.

Your coordinates put you way out in the Gulf of Maine, not in the intertidal on Mackworth Island. Please post updated coordinates here in the comments so we can get you in the right spot on the map.

Thank you,
-the VS team

Thank You very much for commenting on my vital signs, sorry about the google maps it is not working right now and I will try to fix it ASAP.