There are 53 extant Unionids in Texas, six of which are petitioned for federal protection under the Endangered Species Act of 1973. The Louisiana Pigtoe, Pleurobema riddellii, has recorded distribution in Texas, Arkansas, and Louisiana. In Texas P. riddellii historically occurs as far west as the San Jacinto and Trinity rivers, eastward to the Neches, Sabine and Red rivers. Its abundance is low, and an understanding of their life-history and reproductive characteristics is imperative for establishing federal protection status. During the larval stage of Unionid mussels’ life cycle, juveniles are obligate parasites of fish. This study sought to determine the host fish for P. riddellii by collecting wild infected fish from the upper Neches River, and observing each species separately in the laboratory. Juvenile mussels that metamorphosed from the fish were preserved, cataloged, and analyzed genetically. This research indicated the blacktail shiner (Cyprinella venusta) was a host-fish of P. riddellii glochidia, supporting claims that P. riddellii are Cyprinid specialists. Data also characterize adult spawning and juvenile abundance throughout the season. Additionally, I collected gonadal fluid samples of P. riddellii throughout the year to provide insight into population structure, reproductive size, fecundity potential, and spawning. Analyses indicate that P. riddellii exhibit an equilibrium life-history strategy of low to moderate growth rates, and low but variable fecundity throughout their life.

Date of publication

Fall 8-8-2018

Document Type




Persistent identifier


Committee members

Neil Ford, Lance Williams, John S. Placyk, Jr.


Masters of Science in Biology

Included in

Biology Commons