Life Cycle

Born of a Puff
In order to reproduce, female mussels must take in the sperm from a nearby male mussel and then fertilize her eggs internally. Once eggs are fertilized, they become glochidia which are mussel larvae. Female mussels must find a suitable fish host to carry her glochidia upstream. During fish migrations, females release their glochidia into the water in hopes they attach to fish gills and fins. This is a very difficult task as different mussel species use different fish species as hosts. In our case, the Alewife mussel needs an Alewife fish as a host. Some mussel species have evolved part of their body as special lures that they wave around to attract specific fish.

Babies on the Move
If a glochidium manages to attach to the fins or gills of a fish, it stays attached for a few weeks up to a few months depending on the species. Once the glochidium has undergone metamorphosis into a juvenile mussel (similar to a butterfly), the mussel falls off its fish and sinks to the bottom of the stream. Using fish to transport juvenile mussels is quite a clever endeavor since fish are powerful swimmers and can swim against strong currents. This means mussels can move upstream to areas it could not reach by itself and helps spread mussels throughout rivers and tributaries. As more mussels populate our rivers, the healthier and more diverse they become.

Settling into a new home
Life for a juvenile mussel is not easy. Mussels live in ponds and lakes as well as in small streams and large rivers. They live in water that is 4 feet deep to over 40 feet deep! Some natural predators of freshwater mussels include muskrats, otters, raccoons, birds, fish, and other animals that can find and open their shells! Smaller mussels like juveniles are readily eaten by predators because they are easier to crack open. Juveniles that avoid being eaten will continue to grow and live more than 100 years in some cases!