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Species Description

Florida Floater

Utterbackia peggyae


Phylum: Mollusca
Class: Bivalvia
Order: Unionoida
Family: Unionidae


The Florida Floater is a small to medium sized freshwater mussel that usually measures between 1.2 and 3.5 inches (30-90 mm) in length. Its shell is thin and rounded in appearance. The posterior ridge is broadly rounded. The periostracum (outer shell surface) is yellow-green and becomes dark green or brown with age.

Life Cycle

Many of the specific details about the complex life cycle of this rare mussel are not currently known, but the life history of Utterbackia peggyae is presumed to be similar to related species. Male Florida Floaters release sperm into sluggish streams, ponds and lakes. Sperm enters females through siphon-like regions and fertilization of eggs occurs within female shells. These fertilized eggs develop into special larva called glochidia. Glochidia continue to develop and are released into the water column when fully matured. The parasitic glochidia must find and attach to the gills or fins of the appropriate host fish to complete development. The required host species for the Florida Floater are not known at this time. The glochidia parasitize a fish host for a variable length of time, likely depending upon water temperature, fish species and other factors. Larvae transform into juvenile mussels on the fish and then release from the host to find a suitable substrate, often the mud or sand bottom of a sluggish pond, lake or stream.

Natural History

Florida Floater l arvae (glochidia) are parasitic upon tissue of fish hosts while completing the metamorphosis into juvenile mussels. Adult mussels are typically sessile and are found attached to the sand or mud bottom of ponds and lakes. Mussels are also often found buried deeply within sand or mud. Adult mussels are filter feeders and usually feed upon plankton and detritus from their aquatic environment. Florida Floaters bring water from their habitat into their shells through specialized regions that are similar to the true siphons of clams. The water is then filtered over its gills and food particles are trapped and eventually digested.


The Florida Floater is native to the Apalachicola region. Its historical range included the Chipola, Flint and Apalachicola Rivers and tributaries of South Georgia , Alabama and Florida . Today it can be found within the Flint and Apalachicola Rivers of southwestern Georgia .

Conservation Status

The Florida Floater is Rare and Imperiled within Georgia . However, populations appear to be fairly stable. Although this species prefers sluggish waters and is rather tolerant of impoundments, it has presumably been affected by pollution and excess sedimentation.

Similar Species

In appearance, the Paper Pondshell (Utterbackia imbecilis) is the most similar species to the Florida Floater. However, the Paper Pondshell is more elongate in shape and is marked with numerous fine green rays.