Invasive SpeciesRapa whelk

Rapana venosa
NOT FOUND by muffinbuses
Cape Elizabeth Maine
Not Yet Reviewed by Expert
Quality checked by Pp
Peer reviewed by Ib,kh
Field Notes
Field notes : We are at Crescent Beach. The weather is pretty nice, but there is a brisk autumn breeze in the air.The weather outside was cloudy, the sun was hiding through the clouds. I see the very low tide and wet, slippery rocks I could also see kids walking and looking for things. I could hear kids discussing what they found. I smell strong saltwater and dead fish. When we went to the beach I was surprised that I didn't find the species I was looking for (Rapa Whelk) because I think I may have assumed that there would be an ample amount of them, much like common periwinkles. Some problems I ran into were that I felt like every snail I lifted up to look at (which was a lot) it seemed to be the same species (Common Periwinkle).
A sketch of our study site.
Supporting Evidence
Photo of my evidence.
This is not the Rapa Whelk we were looking for, but the common periwinkle. A small, white aperture (opening) is a feature that helps us tell the two apart. The species that we were looking for, Rapa Whelk, has a large dark orange aperture with small teeth along the outer lip. We got this evidence from the Vital Signs ID cards.
Photo of my evidence.
Another piece of evidence is that shell of the Common Periwinkle is smooth, small, and has a couple of bumps. But the Rapa Whelk is supposed to be very bumpy, and the shell is supposed to be thick with moderate sized knobs moving up the sides in a spiral shape. We got this evidence from the vital signs ID sheets.
Photo of my evidence.
The short pointed spire with flattened whorls is the final piece of evidence that helps us to tell the Rapa Whelk and Common Periwinkle apart. The Common periwinkle has a small spiral. The Rapa Whelk Has a big spiral. We also got this evidence from the vital signs ID cards.
Species Observation: Species Looked For
Did you find it?: 
I think I did not find it
Scientific name:
Rapana venosa
Common name:
Rapa whelk
Sampling method: 
Just looking around
Photo of our sampling method.
Place Studied
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Map this species
N 43.562149 °
W -70.219315 °
Observation Site Information
A photo of our study site.
Coastal - Rocky intertidal
Trip Information
Kettle Cove (CEMS 7th Grade)
Trip date: 
Tue, 2014-10-28 09:22
Town or city: 
Cape Elizabeth Maine
Type of investigation: 
Species Survey
Time of low tide: 
Tue, 2014-10-28 08:25


Nicely done! I think you presented a really good argument for why you did not find rapa whelk. Also, that's a lovely sketch!

Cheers and happy observing,