Native SpeciesJonah crab

Cancer borealis
FOUND by StubbyStarfish
2012-05-24
York, ME
ID Questioned
Quality checked by GhillieCrab
Peer reviewed by
Field Notes
We found a multitude of species on our school trip to York Harbor Beach. While searching the cliffs on the left side of the beach, we found a blooming Rosa Rugosa or beach rose. We continued to check the pools of the left side and found a few green crabs, an Asian shore crab, a jonah crab ("The first native crab a student has found in 2 or 3 years," said our teacher), and a limpet or a Chinese Hat. We migrated to the right side, also a rocky cliffside, and found a "baby" sea urchin (about cm long/wide, not really a juvenile) and a tiny starfish with 3 of its appendages replaced with growing stumps, and thus our group name, Stubby Starfishes, was created. After doing some water testing, our entire party gathered on the rocks to share our findings. As we all stood on the pile of rocks, we noticed the beach pea.
A sketch of our study site.
Supporting Evidence
Photo of my evidence.
We found this little guy (or girl) under a rock in one of the groups of tide pools closer to the sea.
Photo of my evidence.
It was about 2-4 cm wide, with 8-10 spines on the sides of its carapace.
Photo of my evidence.
It actually moved slower than the other crabs that we found, and seemed to be less indignant when we picked it up.
Species Observation: Species Looked For
Did you find it?: 
I think I found it
Scientific name:
Cancer borealis
Common name:
Jonah crab
Is it alive?: 
All alive
Count of individuals: 
1-10
Coverage: 
Less than 1/4 covered
Reproduction: 
How big is it?: 
0 - 2 cm
Is it male or female?: 
Can't tell
Sampling method: 
Quadrat (user-placement)
Time search
Photo of our sampling method.
Place Studied
We’re sorry, JavaScript is required to view the map. If JavaScript is you may wish to upgrade to a newer browser in order to view this map.
Map this species
Latitude: 
N 43.133889 °
Longitude: 
W -70.630000 °
Observation Site Information
A photo of our study site.
Habitat: 
Coastal - Beach or dune
Trip Information
Name:
York Harbor Beach
Trip date: 
Thu, 2012-05-24 07:57
Town or city: 
York, ME
Type of investigation: 
Species and Habitat Survey
Ecosystem: 
Coastal
Watershed: 
Time of low tide: 
Thu, 2012-05-24 08:16
Habitat Observations
Species diversity: 
11 different species
Evidence of vectors: 
Boats
Paved road
Walking trail
People
Recent disturbance
Water temperature: 
15.0°C
pH: 
8.1
Dissolved oxygen: 
8.0mg/L
Salinity: 
27.0ppt

Comments

I saw your observation linked to on the best of VS observations page (http://vitalsignsme.org/best-observations) and i had to come check it out. Great photos, great sketch, and you successfully were able to tell that this was one of the two natives (they're so hard to tell apart!).

Nice work!!

~sniffly

You definitely do have a native Maine crab here. But, it can be tough to tell the difference between a Jonah crab and a rock crab. If you look at each spine on this crab, it is pretty smooth and comes to one point, which is why I think this is a rock crab. The spines of a Jonah crab are each very rough and jagged.

Good luck with your field work!