Native SpeciesSmooth periwinkle

Littorina obtusata
FOUND by The Golden Ratio
Cape Elizabeth
Not Yet Reviewed by Expert
Quality checked by Mr. Werner
Peer reviewed by JebronLamers
Field Notes
The cold wind greeted us like a cannon when we stepped off the bus. We were there to collect data for the scientists at Gulf of Maine Research Institute. It was about 62° degrees with the wind blowing 15 miles an hour from the south. The weather felt damp and foggy with the clouds covering 75% of the sky. There was a huge number of periwinkles on a rock bank covered in knotted wrack. We took two specimens, a smooth periwinkle and a rough periwinkle for comparison purposes. Taking photos proved difficult with the wind blowing the specimens off the page every minute, but we got a small victory when the specimen cooperated and stayed still in the sand and let us take pictures. The study site was a large group of tide pools that sat next to a grass-covered point in Kettle Cove.
Supporting Evidence
Photo of my evidence.
This is the smooth periwinkle because this specimen has a tear shaped aperture (opening). This characteristic is specific to the smooth periwinkle. The rough periwinkle has a round opening unlike this specimen.
Photo of my evidence.
Another reason this specimen is the smooth periwinkle is this specimen has a flat spire which is a characteristic of the smooth periwinkle. The periwinkle on the left is our specimen which has a very flat spire compared to the rough periwinkle on the right with a tall spire(tip.)
Photo of my evidence.
The final reason this specimen is a smooth periwinkle is the specimen is the correct size. A smooth periwinkle’s shell can grow to about 1.3 centimeters long, this periwinkle’s shell is slightly smaller than that. This periwinkle falls in the correct size range.
Species Observation: Species Looked For
Did you find it?: 
I think I found it
Scientific name:
Littorina obtusata
Common name:
Smooth periwinkle
Sampling method: 
Just looking around
Photo of our sampling method.
Place Studied
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Map this species
N 43.561329 °
W -70.218501 °
Observation Site Information
A photo of our study site.
Coastal - Rocky intertidal
Trip Information
Kettle Cove Moniz 2017
Trip date: 
Tue, 2017-10-24 09:30
Town or city: 
Cape Elizabeth
Type of investigation: 
Species Survey
Time of low tide: 
Fri, 2014-10-24 08:26


Hi good work