Shovelnose Sturgeon Age and Growth Characteristics and Fish Community Characteristics of the Lower Platte River and Missouri River Near Nebraska

There have been documented widespread losses of freshwater biodiversity over the past several decades. Many of these losses may be due to anthropogenic causes such as habitat alterations, pollution, and overharvest. Shovelnose sturgeon may also be influenced by anthropogenic causes and have experienced declines in population abundance near Nebraska. My objectives were to first to describe the age, growth and mortality of shovelnose sturgeon found in the lower Platte River (LPR). Second, I quantitatively evaluated similarities and differences between the Missouri River (MR) and the LPR fish community composition (presence-absence of species) and structure (abundance of species). We used trammel nets and trotlines to collect shovelnose sturgeon from April through November, 2009. Shovelnose sturgeon in the LPR had high annual mortality (43%) and faster growth characteristics but attained a smaller size than other sturgeon populations throughout its range. I used data collected during summer 2009 using trammel nets (both systems), mini-fyke nets (MR), seines and electrofisher (LPR) to compare communities between the LPR and MR and found that small-bodied fish community compositions were not similar between the LPR and the MR. Conversely, I found that large-bodied fish community compositions were similar between the LPR and the MR, yet using trammel net only data I found community structures were not similar. Shovelnose sturgeon, channel catfish, blue suckers, and goldeye contributed the most to differences in community structure differences. The difference of abundance may be due in part to differences in habitat availability between the LPR and the MR