Invasive SpeciesCommon periwinkle

Littorina littorea
FOUND by 18as
ID Confirmed
Quality checked by Anne
Peer reviewed by Jonas
Field Notes
Marine site: We researched in a transect line, collecting evidence by capturing crabs and periwinkle, then putting them in one bucket until we collecting the evidence about them. Our transect area was cloudy and rocky, and there was a strong wind coming from the north. The area was covered in seaweed and the coastal creatures were hidden under them. There were almost no native crabs found, only green crabs, but there were hundreds of common periwinkles and smooth periwinkles. Only one Rapa Whelk was found and no “live” rough periwinkles were spotted. There was an abundance of knotted wrack clinging to the rocks and ground. We noticed that this was an important hiding spot for the crabs, so we grabbed large chunks of the knotted wrack and pulled it away to find the hidden crabs. Using this method we were also able to find several hidden rough periwinkles and Rapa Whelks. Forest Trail site: The path itself was well maintained, but the foliage around the path was dipping in and out of invasive and native. There were well-maintained areas where the plants were co-existing, and there were places where only one plant could be found. The trail was sunny and warm, providing us with great lighting for the photos. We had about around an hour and a half to walk around the island and record each clump of invasive species. We didn't’ do that much species control, because this was more of a research trip. There was around a hundred Japanese Barberry visible from the path, while other plants like the Glossy Buckthorn were almost non-existent.
Supporting Evidence
Photo of my evidence.
The Spiral tip was blunt yet well defined with no jagged spikes. The Periwinkle's shell was no bigger than an inch and its color spanned from off-white to light tan.
Photo of my evidence.
The opening of the periwinkle is large (compared to the shell) and the aperture is mostly white. This is different from the yellow to orange openings of the rough periwinkles and Rapa Welks.
Photo of my evidence.
The tentacles are clear with black stripes traveling up and down the periwinkle. The body of the periwinkle came out after around 5 minutes of humming.
Species Observation: Species Looked For
Did you find it?: 
I think I found it
Scientific name:
Littorina littorea
Common name:
Common periwinkle
Sampling method: 
Photo of our sampling method.
Place Studied
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N 43.691981 °
W -70.230358 °
Observation Site Information
A photo of our study site.
Upland - Forest
Trip Information
Mackworth Marine Transect Investigation
Trip date: 
Tue, 2018-10-09 07:36
Town or city: 
Type of investigation: 
Species Survey
Time of low tide: 
Wed, 2018-10-03 10:15


Wow! 5 minutes of humming, that takes dedication. I love doing that whenever I am on the coast.