May 042010
Home – Western temperate and cold seas
Habitat – Coasts, estuaries
Niche – Filter feeder
Favorite Food – microscopic food particles
Length – up to 3 inches

Also called common mussels, blue mussels are a familiar sight on the shores of most temperate and cold seas in the western hemisphere. Anyone who’s climbed over beach rocks knows to be careful where they step, lest they cut themselves on sharp clusters of black and blue shells.

Mussels are delicious relatives of clams in a class of ocean creatures called bivalves. A hinged shell is their primary protection, opening while the animals are feeding, and closing when they’re threatened by predators or receding tides. Mussels anchor themselves to rocks with fibrous tissue made of filaments called byssal threads, which taken together are five times stronger than human tendon. The threads make it nearly impossible for mussels to be nipped away or pounded off the rocks by waves, inching them one step closer to living life happy as a clam, so to speak.

Because they rarely move, mussels need their food to come to them. They are filter feeders, capturing tiny bits of food floating in the currents with their feathery gills. They also obtain oxygen in the same way, and can process nearly 20 gallons of water a day, consuming most everything in it. As far as filter feeders go, blue mussels are among the most successful in the ocean.

Unlike their cousins, the freshwater zebra mussels, blue mussels are economically important and are a staple seafood dish worldwide. Because of their high rate of reproduction, wide range, and lack of many natural predators, blue mussels are still common. However, like anything else in the ocean, they’re prone to changes in currents, availability of food, and especially pollution. When an animal lives by sucking water into its body, it won’t live long if there’s crap in the water. So long as we respect that notion, we’ll likely continue to see the shores littered with thousands of those black and blue shells.