Tombigbee River Fishes Before and After the Tennessee-Tombigbee Waterway

Roberts, M. E., Millican, D. S., Calloway, M. T., Turnage, G., Strongin, K., Altig, R., Brooks, C., Slack, W. T., & Taylor, C. M. (2011). Tombigbee River Fishes Before and After the Tennessee-Tombigbee Waterway. Mississippi Chapter of the American Fisheries Society. Starkville, MS.

The physical template of the biologically diverse Upper Tombigbee River was altered in the late 1970’s through its incorporation into the Tennessee-Tombigbee Waterway (TTW). Museum vouchers archived pre-TTW (1953-1983) provided a contrast for collections describing contemporary fish assemblages (2002-2010). We have documented differences in pre- and post-TTW assemblages. Fluvial specialists in the East Fork Tombigbee River declined while habitat generalists such as the western mosquitofish, Gambusia affnis became more prominent in the assemblage. Some fishes occurring throughout the system during both time periods exhibited dietary shifts. Most notable is that of the crystal darter, Crystallaria asprella. It fed primarily on macroinvertebrates pre-TTW and consumed more zooplankton post-TTW. Preliminary data suggest altered interactions between fishes and mussels. The percentage of longear sunfish, Lepomis megalotis, bearing a glochidial load has increased post-TTW. Future work will determine the taxonomic structure of glochidia infestations in these sunfish to provide insight into how mussel assemblages have changed. Also, stable isotopes may be used to characterize the history of trophic structure in the system.