Fast facts about freshwater mussels | Things to Know

There are hundreds of mussels species worldwide. But in the United States, the number of native freshwater species has dwindled. Watch this video to learn more about the important role mussels play in freshwater ecosystems, how scientists are trying to help them and some of the surprising ways that they trick fish into helping distribute their young.

And check out our article “The hidden strengths of freshwater mussels.”

Video Transcript:

If you’ve ever slurped down an oyster or dug for clams, you’ve encountered a bivalve. Bivalves are a large class of shellfish. They have a two-parted shell that opens and closes with a hinge. They live in waters all over the world, from the Arctic to deep ocean and sandy beaches.

Freshwater mussels live in fast-flowing streams and rivers. Ecologists refer to these bivalves as “ecosystem engineers,” because they play a big role in shaping their environment. Their breathing and feeding filters the water, removing dirt and pollution, and allowing sunlight to greater depths, which helps oxygen-producing plants and the aquatic life that depends on them.

But many native freshwater mussels are in trouble. Their habitat has been changed dramatically by dams, which alter the water’s temperature and how fast and deep a river flows. Scientists are trying to help by raising young mussels in tanks and releasing them back into the wild.

Freshwater mussels have evolved a fascinating way to give their young a head start. Mama mussels have tricks to attract fish that will temporarily host her baby mussels, called glochidia, in their fins or gills. Some mamas, like this lampsilis, make fleshy lures that resemble crayfish or minnows. The mom releases her glochidia in a cloud, and the young mussels harmlessly grow in the fish for several months until they drop out and burrow into a new home, in a new location. Other mussels, like the Ouashita kidneyshell, package their young in a sac that resembles a small fish to prompt a real fish to snap it up. Being a mama mussel like this riffleshell requires patience.

Scientists are still learning about which host fish each mussel species prefer, and investigating how much mussels can help restore waterways that have been degraded by dams and pollution. In the future, mussels might be able to help save the rivers and streams they depend on.