Using this image and additional resources, the Nature Guardians conducted a periwinkle population survey to gain practical skills in marine species identification and survey techniques!

Periwinkles originally came from the Atlantic coast of Europe but have been in our waters for centuries. Periwinkles are adapted to live both in and out of water. They spend most of their time underwater eating food, and when they are not in the water, they have to survive desiccation (drying out) under the pressures of the sun and air. Periwinkles are mollusks and are essentially marine snails. They come out of their shell underwater, crawling along the ocean floor and rocks. To eat food like diatoms and species of algae, they use a tooth-like structure called a radula. When the tide goes out, the periwinkles find a safe place, like between rocks, tidal pools, or under seaweed, where they have as much moisture as possible. They then squeeze tightly into their shell and move so that their operculum acts as a door, protecting them from the external environment. They also secrete a sticky mucus substance that allows them to stick and seal themselves safely to rocks.