Invasive SpeciesCommon periwinkle

Littorina littorea
FOUND by Partywinkles
Cape Elizabeth
ID Confirmed
Quality checked by Mrs. Moniz
Peer reviewed by Potato Finders
Field Notes
We stepped off the bus and were welcomed to Kettle Cove Beach with the thundering sound of the waves crashing on the shore of the sandy beach at 9:16 AM on October 24th, 2017. It was a cloudy day with the sun only slightly peeking through a small opening in the clouds. It was a flood tide, the tide was rising up on the shore, just coming back from low tide. The wind was rough, pushing materials and people around. The scent of seaweed was distinct and strong, and it was everywhere, a thick layer of it covering the rocks. Water was coating the rocks causing them to be slippery and wet, this was an obstacle we had faced during our time at Kettle Cove. Above us, the sky was filled with seagulls flying and squawking. It was slightly cold, being at 62 degrees fahrenheit, but the lack of sun made it more of a brisk day. We were searching through the rocks and seaweed for the Common Periwinkle, and it was plentiful and surprisingly easy to find, being all over the rocks in almost everywhere. We are doing this to help Vital Signs and the Gulf of Maine Research Institute to find the invasive species in Maine so they can recognize and handle them.
A sketch of our study site.
Supporting Evidence
Photo of my evidence.
We think we found the Common Periwinkle. The Periwinkle had the features we were looking for; horizontal lines on the shell and the purple-brown color. The reason that we know this is the Common Periwinkle and not the Rough Periwinkle is because the Rough Periwinkle has vertical lines, and the Common Periwinkle has horizontal lines.
Photo of my evidence.
One more reason we believe that the organism we found is the Common Periwinkle is because of this photo. It helps us to support this statement because you can see the spiraled and pointed tip, and those are both important features of the Common Periwinkle. One of the Common Periwinkles shows the pointed tip while the other shows the spiraled end.
Photo of my evidence.
This last photo shows the Common Periwinkle. The ID sheet made by Vital Signs states that the Common Periwinkle has a white opening in the shell, and this photo shows that bright white aperture (opening) inside the shell of the organism. The Common Periwinkle is the only Periwinkle with this feature, showing that this cannot be the rough or smooth periwinkle.
Species Observation: Species Looked For
Did you find it?: 
I think I found it
Scientific name:
Littorina littorea
Common name:
Common periwinkle
Sampling method: 
Quadrat (user-placement)
Photo of our sampling method.
Place Studied
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Map this species
N 43.561286 °
W -70.217796 °
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


is gorgeous!