Pallid sturgeon (Scaphirhynchus albus) is a native North American fish that was listed as a federally endangered species in 1990 due to failure in spawning and recruitment, perhaps as a result of human modifications to their habitat. The upper Missouri River basin pallid sturgeon have been shown to be genetically distinct from other pallid sturgeon. Since there has been no natural recruitment in the upper Missouri River for several decades, perpetuation of this genetically distinct unit is reliant on propagation using remaining wild fish as broodstock. The expense associated with acquiring unique individuals from the remaining wild broodstock is causing wild collection to become a less viable option each year. It has been proposed that rearing progeny of wild broodstock fish in a hatchery setting as captive broodstock may be feasible alternative to wild collections. The genetic risks associated with the creation of a captive broodstock need to be investigated and a captive management plan needs to be developed prior to the implementation of a captive broodstock program. The relatedness values and the effective population size for the wild caught founders were determined by genotyping wild upper Missouri River pallid sturgeon at 16 previously developed microsatellite loci. The founding wild broodstock were shown to encompass an ample amount of genetic variation and a sufficiently large effective population size. The broodstock currently housed as Gavin's Point National Fish Hatchery can be exclusively used for the propagation of pallid sturgeon to be stocked in the upper Missouri River with the caveat that descendents from each wild fish will be spawned in the future and that the reproductive variance of the broodstock be controlled to maximize Ne and thus reduce inbreeding.

Growth rates and diet patterns for sympatric pallid sturgeon Scaphirhynchus albus and shovelnose sturgeon S. platorynchus throughout the Missouri River and lower Mississippi River were examined. Pallid sturgeon growth in the Great Plains Management Unit (GPMU) was slower than in other river reaches until age 9 and pallid sturgeon from the Interior Highlands Management Unit (IHMU) and Coastal Plain Management Unit (CPMU) did not differ. No differences in growth between management units were detected for shovelnose sturgeon. Observed differences in growth between pallid sturgeon and shovelnose sturgeon were generally dependent upon which growth model was used, but pallid sturgeon were typically larger after age 4. Diet is considered a primary driver of growth. Stable isotopes are capable of examining diet over longer time periods than gut content studies, but that time frame is dependent on which tissue is selected. Using fin clips, diet of both pallid sturgeon and shovelnose sturgeon was evaluated via stable isotopes. Pallid sturgeon and shovelnose sturgeon trophic position (TP) was influenced by management unit. There was a slight, but not significant, latitudinal trend with pallid sturgeon TP increasing by approximately one full TP between the GPMU and CPMU. Pallid sturgeon growth was negatively related to TP but was unrelated to δ13C in the Missouri River. Shovelnose sturgeon growth was not related to TP, but was negatively related to δ13C in the Missouri River. Dissimilarity in TP combined with differences in δ13C between species suggests low diet overlap between these sympatric species, and neither species should be used as a surrogate for the other for prey consumption studies. Further, pallid sturgeon differences between the GPMU and the rest of the management units suggest that individuals from the GPMU could be managed separately from those in other management units.