Native SpeciesRock crab

Cancer irroratus
Cape Elizabeth
ID Confirmed
Quality checked by Mrs. Moniz
Peer reviewed by Supreme Seals
Field Notes
The day was warm and windy when we went looking for the Rock Crab. Clouds covered the sky. A scent of salt accompanied the consistent, comforting sound of the waves crashing on the shore. There was a slight mist to the air, not enough to limit your sight, but enough to make it feel colder. We went to Kettle Cove, a small, rocky beach in Cape Elizabeth, Maine. We were looking for the native species so we could prove that it had not been crowded out of its natural habitat by invasive species and find evidence. One-hundred twenty kids accompanied our group to find a native or invasive species. My group found a rock crab quickly. The high tide time was 2:41 and low tide was 8:30 AM so at 9:30 AM, which was the time of our visit, it was at a flood tide. A flood tide is when the water is coming up and the beach is shrinking. The precipitation was 0.16 inches throughout the day, but 0 inches when we were there. The air temperature was 61ºF and the wind was going west at 13 mph.
Supporting Evidence
Photo of my evidence.
This photo shows a rock crab. The rock crab has 8-10 spines on each side of its eyes. Spines are the parts of the shell that protrude from the rest. This particular crab had 9 spines on each side. We circled the spines in green. The spines are also one of the main factors that lead me to believe that this crustacean is a rock crab and not a Jonah crab. Jonah crabs have multiple points per spine, while rock crabs only have one. This photo is underwater which is responsible for the shading.
Photo of my evidence.
This photo shows a rock crab. We know that it is a rock crab because rock crabs have purple spots on their shell. This crab has so many spots that it appears red/purple. We circled the spots in red.
Photo of my evidence.
This photo shows a Rock crab. We know that this is a rock crab because the underneath of it's legs are white, which is a characteristic of the rock crab.
Species Observation: Species Looked For
Did you find it?: 
I think I found it
Scientific name:
Cancer irroratus
Common name:
Rock crab
Sampling method: 
Just looking around
Photo of our sampling method.
Place Studied
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Map this species
N 43.561100 °
W -70.217500 °
Observation Site Information
A photo of our study site.
Coastal - Rocky intertidal
Trip Information
Kettle Cove
Trip date: 
Tue, 2017-10-24 09:30
Town or city: 
Cape Elizabeth
Type of investigation: 
Species Survey
Time of low tide: 
Tue, 2017-10-24 08:26


Very well presented evidence!