Photos From the Field

FRESHWATER MUSSELS LIVING ON OTHER SPECIES & OTHER SPECIES LIVING WITHIN MUSSELS

By Michael Davenport, Marine Species & GIS Programs Manager

Left: a killifish with attached glochidia.  Right: a crayfish taking shelter within a mussel shell.  © Mike Davenport
Left: a killifish with attached glochidia. Right: a crayfish taking shelter within a mussel shell. © Mike Davenport

The images above were taken during a recent survey of the Raritan River in Somerset County.  The image on the left is a Banded Killifish with the larval stage of freshwater mussels attached (the small black dots on the side of the fish are the larval mussels, known as glochidia).  Glochidia are parasites of fish, and some other aquatic animals, which will drop-off at the end of their larval stage, and then complete their life cycle in the bottom of the river, stream, or lake as the adult mussels most people are familiar with.  The host fish not only provides a meal for the glochidia, but also enables mussels to travel further than they can as an adult.

The image on the right is a crayfish which took shelter within the old shell of a freshwater mussel, in this case an Eastern Elliptio.  Other freshwater invertebrates may reside within old mussel shells, such as snails and aquatic insects.

To learn more about freshwater mussels in New Jersey, visit our Freshwater Mussel site.