Eastern Fan Shell
The Eastern Fan Shell
is rounded, solid and inflated. This mussel is found in medium to
large rivers. It buries itself in sand or gravel in deep water with
only the edge of its shell and its feeding siphons exposed. To its fish
host, a fanshell larva looks like a worm. When the fish host attacks,
the larva attaches itself to the gills, and stays there while it grows
a shell and is a small fanshell.
The Eastern Fan Shell need undisturbed water and a supply of fish hosts for reproducing. The male discharges sperm into the water, the females downstream siphon the sperm to fertilize their eggs, which they store in their gill pouches until the larvae hatch. The females discharge the larvae clusters, which resemble spiral worms, which attach themselves to the fish's gills. Once they grow their shells, they seperate from the fish and settle into the riverbed. They can live for as long as 50 years.
Reason for the species decline in population:
Most of the mussel's locations have been reduced by dams and reservoirs changing the gravel and sand habitat. Dredging the river channels and sand and gravel mining also destroys fanshell habitat. Erosion caused by strip ming, logging and farming adds silt to many rivers.Pollution for agricultural and industrial run-off can damage the mussels. Chemical and toxic metals can become concentrated in the body tissues of the mussels eventually poisoning it ot death.
To save the Fanshell, the State and Federal laws must be enforced. Some of the habitats need to be restored. Research is needed to determine the required habitat and the fish hosts.