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Whitecap limpet

Acmaea mitra


This limpets shell is smooth, white and circular with its apex near the center. The two that I found were about 3 cm in dia. and 3 cm tall. They are covered in pink encrusting alga, which ironically is its favorite food.


Spotted in tide pools at Tongue Point. Range: Aleutian Islands, Alaska to Baja California.


The scientific name means "pointed cap". This species eats coralline aglae using its radula. A. mitra is also fairly unique amoung limpets as it does not appear to have any defense response system to predators. Predators include the seastar Orthasterias koehleri and birds such as black oystercatchers and white-winged scoters. Formerly nearly all our intertidal limpets were classified in family Acmaeidae. Now most of the others have been moved to family Lottiidae, and this is the only species left in family Acmaeidae.

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Machi 10 months ago

Yes it really adds a surreal touch when you see a tide pool that is bubblegum pink! Especially next to all the other fantastic colors.

Brian38 10 months ago

Thank you so much Machi. I couldn't agree more - I was sort of mesmerized by all the pink algae in some pools. In a few of the calmer pools it had completely covered large mussels as well.

Machi 10 months ago

Nice find! I am always in awe of how much that pink algae takes over in tide pools here as well. That little urchin is lovely too!

Spotted by

Washington, USA

Lat: 48.17, Long: -123.71

Spotted on Apr 20, 2019
Submitted on Apr 27, 2019

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