Master of Science (MS)


Renewable Natural Resources

Document Type



Crayfish are important for stability, determining ecosystem structure, and ecosystem functions in freshwater habitats. Louisiana has many endemic species of crayfish, but most are poorly described. This study investigated the populations of some of the lesser known crayfishes in the South Central Plains. Specifically, the goals were to examine movement, movement across anthropogenic barriers, and estimate population size of 10 species reported from the area: Procambarus natchitochae, P. vioscai, P. clarkii, P. acutus, P. zonangulus, P. tulanei, P. kensleyi, Orconectes maletae, O. lancifer, and O. palmeri. In combination with a field team, I sampled twelve wadeable streams with DC backpack electrofishers and traps at least twice at 2-3 month intervals during summer, fall, and winter of 2014. Although all sampled crayfish of sufficient size were double marked, recaptures were minimal, thus, generalized N-mixture models were performed on the three most widely captured species to generate population and transience estimates based on sampling unmarked animals over time. All population estimates were very low and were dependent on river basin, specific conductance, and stream width. Although the relationship among species and river basins has been previously described, relationships with stream size and specific conductance were novel. P. natchitochae and P. vioscai appeared to spatially segregate along a gradient of stream size. Specific conductance, which is an indicator of available calcium, had a positive association with abundance for P. vioscai, P. natchitochae. P. natchitochae and P. vioscai showed the possibility of seasonal transience and potential relationships with dissolved oxygen. These results give conservation scientists and managers more information for conservation of Louisiana crayfishes.



Document Availability at the Time of Submission

Release the entire work immediately for access worldwide.

Committee Chair

Kaller, Michael