Mussels are a type of clam that have a long shell. Mussels live in the same place their entire lives (they are “sedentary”) and fix themselves in place by their byssal threads. Byssal threads, which are also known as “beards”, are made by the mussel as a liquid, but mix with the seawater to latch onto rocks.

Mussels change size throughout the year! They are the biggest in October but shrink and are the smallest in March.

Range and Habitat

Mussels live on the coast of North America from California to Alaska. Mussels live in the intertidal zone, which can be under water or on dry land, depending on the tide. This habitat has dramatic changes in sunlight, salinity (salt levels), and oxygen availability. To survive these changes, mussels seal themselves closed, trapping sea water within their shells.

Life Cycle

The lifespan of a mussel depends on the specific species. Mussels in British Columbia usually live 2-3 years.

Animal Uses

Mussels play an important role in marine food webs. The Dog Whelk, a type of sea snail, is one of the main non-human predators of mussels. To attack the mussel, Dog Whelks create a hole in the mussel’s shell and consume the mussel through the hole. However, mussels can fight back! If the mussel reacts fast enough, it can use the same tool it uses to attach to rocks – its byssal threads – to trap the Dog Whelk onto its shell. The Dog Whelk can still eat the mussel but stays stuck to its shell and also dies.

Traditional Uses by Indigenous Peoples

Common traditional food source

Other Uses

Mussels’ byssal threads are incredibly strong and can stick themselves to most surfaces! Scientists are now attempting to develop a glue based on mussels’ byssal threads for use in surgery. Mussels are also a popular food, often cooked in broth. Mussel meat is very rich in protein. In fact, it contains more protein than beef stock! It also is relatively low in fat and calories, making it a nutritious choice of seafood.


COSEWIC: Not at Risk
CDC: Yellow

Photo: Andreas Trepte