The way of life of periwinkles
Just like seaweeds, periwinkles are distributed along the foreshore according to the preferences of each species. The life styles of periwinkles vary according to their place on the foreshore !
Seaweed and periwinkles
In the middle of the large brown seaweed present on the rocks, you will find many shells with multiple shapes and colors. The seaweed shelters them and brings them the food they need. The different species of algae are distributed in layers according to the conditions of exposure to humidity, desiccation, salinity, the different species of periwinkles are generally distributed according to these algal layers.
Each one has its own home and preferences! Some species can only be found on the top of the seashore, because they prefer the dryness when the sea withdraws at low tide. This is the case, for example, of the rock littorine which lives at the level of the pelvéties, the first brown algae that can be found on the top of the foreshore.
Staying a little longer underwater
Other species are fond of more humid environments and stay underwater longer during low tides. These species will therefore be found lower down on the foreshore, in the middle of denser algal species. This is the case, for example, of the obtuse littorine which feeds on bladderwrack. This small shellfish strongly resembles the floaters of the seaweed where it lives, which allows it to go unnoticed in its habitat.