Endangered Species
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Tubercled-Blossom Pearly Mussel(Epioblasma torulosa torulosa)


photo of tubercled-blossom pearly mussel


Deforestation and intensive agriculture from the time of early settlement were dominant factors in the demise of these mussels.


Status: Endangered


Habitat: This mussel is found in large rivers, in shallow sand and gravel shoals with rapid current.


Behavior: Reproduction requires a stable, undisturbed habitat and a sufficient population of host fish to complete the mussel's larval development. When the male discharges sperm into the current, females downstream siphon in the sperm in order to fertilize their eggs, which they store in their gill pouches until the larvae hatch. The females then expel the larvae. Those larvae that manage to attach themselves to the gills of a host fish grow into juveniles with shells of their own. At that point they detach from the host fish and settle into the streambed, ready for a long (possibly up to 50 years) life as an adult mussel.


Why It's Endangered: This mussel was once quite abundant throughout all the major rivers of the eastern U.S. and southern Ontario. It was particularly numerous in the Ohio River Valley. Increased turbidity and siltation caused by deforestation, and the spread of intensive agriculture were major factors in the decline of this species. The last individual collected was a freshly dead one found below Kanawha Falls, West Virginia in 1969. There have been no sitings since. The species may well be extinct.


Other factors that probably helped do in this mussel include the building of dams and reservoirs and pollution from agricultural and industrial runoff.


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Last updated: October 10, 2018