Invasive SpeciesAsian shore crab

Hemigrapsus sanguineus
FOUND by GhillieCrab
York, ME
ID Confirmed
Quality checked by StubbyStarfish
Peer reviewed by
Field Notes
While we were at the York Harbor Beach looking for invasive and native species, we discovered three Asian shore crabs hiding beneath the rocks. We knew they were Asian shore crabs when we inspected them closely, because they had square shaped shells, banded legs, and three spines on the outside of each of their eyes. Along with the Asian shore crabs, we also found a Rough periwinkle and a Smooth periwinkle. They were fairly easy to identify because of the texture and shape of their shells. We also found lots of seaweed and kelp, clumps of it lined the beach. The weather was warm but cool at the same time, and it was cloudy and very misty. It was hard to see very far down the beach on account of the mist and fog. The air smelled of salt and was damp. While we were looking for species, the tide stared to come in, and we had to retreat farther up the rock on the beach so that we did not fall in.
A sketch of our study site.
Supporting Evidence
Photo of my evidence.
We found it under one of the larger rocks on the beach when we were looking for species, and it met all of the requirements of being an Asian shore crab. The evidence we gathered when we looked closely at it was that it had three spines outside each eye, a square shell and banded legs. All traits of the Asian shore crab. In this photo you can see the Asian shore crab and can see its banded legs and square shell shape. It has long legs and matches other written and photographic evidence of Asian shore crabs.
Photo of my evidence.
In this picture you can really make out the yellow and black pattern on the Asian shore crab's legs. You can clearly see the long legs and the square shaped shell, which supports the claim that it is an Asian shore crab. You may not be able to make it out in the picture because they are so small, but when we examined the crab closely we could see the three spines that bordered the outside of each of its eyes.
Species Observation: Species Looked For
Did you find it?: 
I think I found it
Scientific name:
Hemigrapsus sanguineus
Common name:
Asian shore crab
Is it alive?: 
All alive
Count of individuals: 
How big is it?: 
2 - 5 cm
Is it male or female?: 
Can't tell
Sampling method: 
Just looking around
Quadrat (user-placement)
Time search
Photo of our sampling method.
Place Studied
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Map this species
N 43.131417 °
W -70.638053 °
Observation Site Information
A photo of our study site.
Coastal - Beach or dune
Trip Information
York Harbor Beach
Trip date: 
Thu, 2012-05-24 07:57
Town or city: 
York, ME
Type of investigation: 
Species and Habitat Survey
Time of low tide: 
Thu, 2012-05-24 08:16
Habitat Observations
Species diversity: 
Evidence of vectors: 
Paved road
Walking trail
Recent disturbance
Water temperature: 
Dissolved oxygen: 


I really liked your very detailed description of the crab and how you identified it.