Common periwinkle

Can survive in ice

Even if the common periwinkle can survive being frozen in, most individuals usually wander into deeper water during the winter. They do not hibernate, but their metabolic rate decreases because their body temperature decreases to that of their surroundings.
    The common periwinkle is found from the Barents Sea to Portugal and along the Atlantic seaboard of America from Labrador to Virginia.

Eats brittle algae

The common periwinkle eats many types of algae, but mainly short-life and fast-growing specie, i.e. sea-lettuce, brunslick and purpurhinnor. It cannot eat large and healthy brown algae, but dying plants that collect on the bottom, in seaweed banks and in crevices and depressions are often eaten.
    Many fully grown perennial algae have the ability to protect themselves from grazing periwinkles by the use of chemical repellants or a hard calcareous skeleton, which the young (1 mm) sprouts are unable to do. Even small larvae that have recently fallen to the bottom, i.e. barnacles, can be eaten by the grazing periwinkles. Common periwinkles even eat diatoms and larvae. Grazing periwinkles can be so intensive that the rock surface can appear quite bare (devoid of algae) where they have rampaged in large numbers.
    Periwinkles are often seen grazing in mucus tracks after other snails. The reason is believed to be that extra good food is found there. The mucus itself contains nutritious substances, that has furthermore been enriched by the addition of organic material being stuck in the mucus, and of the rich microflora that find this comfortable environment congenial.

The shell protects against crabs, fish and birds

Young periwinkles run a great risk of being eaten by i.e. the common shrimp, the shore crab and eiders. Large adult periwinkles are well protected in their thick shells that can only be broken by their largest enemies.

Previous page

Page 2 of 4

Next page

Returns home?

Glue their shell

Can survive in ice

Eats brittle algae

The shell protects

Worms in their shell

Pelagic larvae

Many are


Common periwinkle     More facts     Other names
Home    Contents    Inspiration    Facts    Collaboration   
© Aquascope 2000   Tjärnö Marine Biological Laboratory, Strömstad, Sweden
Bo Johannesson | Martin Larsvik | Lars-Ove Loo | Helena Samuelsson