Endangered Species
Midwest Region



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Purple Cat's Paw
(Epioblasma obliquata obliquata)


Photo of three purple cat's paw pearlymussel shells. Photo by G. Thomas Watters, Ohio State University


Of the three known populations of this mussel, only one appears to be reproducing.


Status: Endangered


Habitat: This mussel lives in large rivers of the Ohio river basin. It prefers shallow water and requires a swift current to avoid being buried in silt. It is found on bottom substrates ranging from sand to boulders.


Behavior: Reproduction requires a stable, undisturbed habitat and a sufficient population of fish hosts 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 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: The extreme rarity of this mussel now reduces the chances of successful reproduction. Other threats include gravel dredging of rivers(which disturbs habitat) and pollution. The pesticides and fertilizers used in intensive agricultural practices contaminate rivers and streams-and become concentrated in the body tissues of such filter-feeding mussels as the purple cat's paw.


Most of the purple cat's paw populations were apparently lost when many sections of the bigger rivers in which it lived were converted to a series of large impoundments.


Zebra mussels, an exotic (non-native) species which is spreading rapidly throughout the eastern U.S., also pose a threat. By attaching in great numbers to native mussels such as the purple cat's paw, Zebra mussels suffocate and kill the native species. The purple cat's paw may be doomed.


Back to Freshwater Mussels




Last updated: September 21, 2016